Search

Simple Summary: Warm-blooded animals (like mammals and birds) living in colder climates (higher latitudes or elevations) tend to have larger bodies compared to their relatives in warmer areas. This pattern has been interpreted in terms of heat budget: since the surface area-to-volume ratio decreases with increasing size, larger animals need to produce relatively less heat to maintain stable body temperatures (Bergmann's rule). This mechanism cannot operate in cold-blooded animals, like most insects, as they do not produce heat. In these animals, a reverse pattern is frequently observed, as an increased surface area-to-volume ratio may allow for more rapid heating and cooling. However, selection for more stable internal temperatures might lead to smaller surface area-to-volume ratios also in cold-blooded animals, leading to a negative correlation between body size and temperature. An analysis conducted on tenebrionids along an elevational gradient in Central Italy revealed that, on average, their surface area-to-volume ratios decline with increasing elevation, thus indicating the importance of heat conservation. However, while in species living under bark or in rotten wood, body size (mass and volume) tends to increase with elevation, in ground-dwelling species, it declines up to about 1000 m and then increases. This suggests that a reduction in resource availability with increasing elevation limits body size in ground-dwelling species up to a certain elevation but not in those living under bark, which benefit from more microclimatically stable conditions and constant resources and need energy for overwintering. In endotherms, body size tends to increase with elevation and latitude (i.e., with decreasing temperatures) (Bergmann's rule). These patterns are explained in terms of heat balance since larger animals need to produce less heat relative to their size to maintain stable body temperatures. In ectotherms like most insects, where this mechanism cannot operate, a reverse pattern is frequently observed, as a higher surface area-to-volume ratio in colder climates may allow for more rapid heating and cooling. However, patterns of increasing body size with decreasing temperatures can also be observed in ectotherms if selection for more stable internal temperatures leads to smaller surface area-to-volume ratios. Data on tenebrionids from Latium (Central Italy) were used to model elevational variations in average values of body size (total length, mass and volume) and surface area-to-volume ratio. Analyses were performed by considering the whole fauna and two ecological groups separately: ground-dwelling species (geophilous) and arboreal (xylophilous) species. The surface area-to-volume ratios declined with increasing elevation in all cases, indicating that the need for heat conservation is more important than rapid heating and cooling. However, in xylophilous species (which typically live under bark), body size increased with increasing elevation, and in geophilous species, an opposite pattern was observed up to about 1000 m, followed by an increasing pattern. This suggests that a reduction in resource availability with elevation limits body size in geophilous species up to a certain elevation but not in xylophilopus species, which benefit from more climatically stable conditions and constant resources and need energy for overwintering. [ABSTRACT FROM AUTHOR]

Simple Summary: Currently, the optimization of mass rearing conditions for insects is a matter of highly applied and fundamental relevance since insects can be used as a source of protein in feed and feed supplements for farm animals as well as a source of antibacterial compounds for drug development and various insect research activities in laboratory conditions. The quantity and quality of the consumed feed has an effect on insect growth rate, duration of development, body weight, ability to spread, and survival, as well as on the mating success rate and total egg production of females. Suboptimal nutrition, growth, and development can affect beetle viability. We developed an artificial fungi-based diet for rearing an insect group adapted to life in wood and using it as one of their food sources and tested the effect of this diet on various parameters of the insects' development and their immunity. Zophobas atratus (Fabricius, 1775) (Coleoptera: Tenebrionidae) was chosen as a model species (representative of this group of insects). Based on the parameters of development at all stages of Z. atratus and screening of hemolymph antibacterial activity of their larvae, we showed that the cultivation method we developed shortens the development time of beetles and strengthens their immunity. The rearing of saproxylic insects in laboratory conditions is an important task for studying the biology of insects. Through understanding nutritional needs, it is possible to optimize beetle rearing in laboratory conditions. In this study, an artificial fungi-based diet (FD) was developed for the cultivation of the darkling beetle Zophobas atratus (Fabricius, 1775) (Coleoptera: Tenebrionidae) in laboratory conditions as a model object for studying the biology of saproxylophagous beetles. To assess the influence of the diet, a number of physiological parameters were measured, including development time, body size, and weight of all stages of the beetle's life cycle, as well as its immune status. The immune status of Z. atratus was assessed on the basis of larval hemolymph antibacterial activity against six different bacterial strains assessed using disk-diffusion and photometric tests. Our findings show that the FD reduces development time and boosts the immune status as compared to beetles reared on a standard diet (SD). Samples from FD-reared larvae had pronounced antibacterial activity as compared to samples from SD-reared larvae. This work is of fundamental importance for understanding the correlations between nutrition and development of saproxylic Coleoptera and is the first report on immune status regulation in this group of insects. [ABSTRACT FROM AUTHOR]

Simple Summary: Yellow mealworm farming (Tenebrio molitor, Linnaeus, 1758) for food and feed is considered a more sustainable protein production method than livestock farming. Diets have an impact on the environmental and economic sustainability of the entire production cycle; as a result, there is a great interest in by-product-based diets. However, most evaluations of the efficacy of new diets are generally focused on larval performance, neglecting their suitability for the oviposition phase. The aim of this study was to validate diets supplemented with tomato pomace over a full breeding cycle. As an oviposition substrate, all the tomato pomace-supplemented diets outperformed the bran-yeast control diet (95:5 ratio). During the larval growth phase, the bran-tomato pomace-brewer's spent grain diet and the bran-tomato pomace-yeast diet performed similarly to the control diet supplemented with yeast. These diets were found to be suitable for the entire production cycle, demonstrating their efficacy in supporting larval growth. In conclusion, tomato pomace can be a valuable by-product in developing effective diets for T. molitor, most likely due to its contribution to sterols and fatty acids. Furthermore, its use could provide an alternative to the costly yeast-based supplement. By-product-based diets have the potential to improve the environmental and economic sustainability of Tenebrio molitor (Linnaeus, 1758) production. However, evaluations of the efficacy of new diets are generally focused on larval performance, while the effect on adults is poorly understood. This aim of this study was to evaluate diets enriched with tomato pomace over a complete breeding cycle. The results showed that when used as an oviposition substrate, all the tested diets, including tomato pomace (T), outperformed the control bran-yeast diet (WY, 95:5 ratio), possibly due to the presence of cholesterol and linoleic acid. The adults fed with the bran-tomato pomace-brewer's spent grain diet (WTB, 50:27:23 ratio), the bran-tomato pomace-yeast diet (WTY, 50:41:9 ratio), and the bran-tomato pomace diet (WT, 50:50 ratio) produced significantly more larvae than those fed with the WY diet. The WTB diet (despite being yeast-free) performed similarly to the WY control diet during the subsequent larval growth phase, making it suitable for the entire production cycle. In conclusion, the results show that tomato pomace can be used a valid by-product in the formulation of efficient diets for the breeding of T. molitor and also provide an alternative to expensive yeast. [ABSTRACT FROM AUTHOR]

Simple Summary: One of the main differences between the modern fauna of steppe and desert-steppe insects and the similar fauna of the Last Ice Age is the current leading position of darkling beetles (Coleoptera, Tenebrionidae), which are represented in fossil faunas only by singletons. We hypothesize that the reason lies in the insufficient cold resistance of these insects for successful overwintering. We studied the cold resistance of adults from five species of darkling beetles from the Altai Mountains that overwinter in the soil and the larvae from one such species. The ranges of three of these are limited from the north by the desert-steppe margin of Central Asia with extremely low air temperatures. More than 50% of individuals of these species in the experiment did not withstand cooling below −22 °C. Temperatures in the soil of natural habitats at a depth of 10 cm are close to or lower than the above values. Overwintering is therefore possible in places with greater snow thickness (hollows, wind shade of shrubs and large cereals). Since darkling beetles are now on the border of temperature resistance in the Altai, they likely did not exist in the much more severe conditions of the glacial periods in the Altai Mountains, West Siberian Plain, and Northeast Asia. The level of diversity and abundance of darkling beetles (Coleoptera, Tenebrionidae) is the main difference between the late Pleistocene and modern insect faunas of arid regions. In the Pleistocene assemblages they are extremely rare, whereas in the modern ones they predominate. It is assumed that the reason for their rarity in fossil entomological complexes is their lack of cold resistance. The supercooling points (SCP) and low lethal temperatures (LLT) of adults from five species of Altai darkling beetles that overwinter in the soil and larvae from one such species were measured in the laboratory. All beetles supercooled at negative temperatures but could not survive freezing, with the average SCP of the most cold-resistant species between −25.7 and −21.7 °C (Bioramix picipes, Anatolica dashidorzsi, and Penthicus altaicus). However, 50% of the individuals from different species in the experiment died after exposure during two days at temperatures ranging from −22 to −20 °C. The focal species are distributed in parts of Central Asia with an extreme continental climate, and the temperatures measured in the soil of these natural areas turned out to be lower than or close to the limit of cold resistance of the beetles. Overwintering of darkling beetles is therefore only possible in areas with deep snow: in hollows, under bushes, and under large cereals. Darkling beetles with poor cold resistance could not have existed in the colder climate of the late Pleistocene, which explains their absence from fossil fauna. [ABSTRACT FROM AUTHOR]

Simple Summary: Rearing substrates based on agri-food by-products are ideal for converting bioactive-rich waste and increasing insect quality. This approach is limited by the need to provide nutritionally balanced diets for farmed insects. In this study, we evaluated the possible use of tomato pomace (TP), an agro-industrial waste from tomato processing, as a component in rearing substrate for Yellow Mealworm (Tenebrio molitor). We compared bran-based diets with tomato pomace (0%, 27%, 41%, and 100%). As brewer's spent grain and yeast, protein sources are used in mixed diets to ensure equal protein contents to the diet control. The results showed no difference in larval performance between diets, except for a longer time of the development in the TP100 diet. Generally, the efficiency indices worsened in diets with increasing TP. Conversely, lycopene and β-carotene increased in the harvested larvae, and the fatty acid composition wasimproved, with an increase in polyunsaturated fatty acids. Maximum qualitative increases were obtained with the TP100 diet. The TP41 diet is the best balance between larval performance and qualitative improvement. Therefore, tomato pomace is suitable for the formulation of mealworm diets, even in high dosages when supplemented with proteins and carbohydrates. Tomato pomace (TP), an agricultural industrial waste product from the tomato processing industry, is valorized as a rearing substrate for Tenebrio molitor (L.). This study evaluated bran-based diets with increasing tomato pomace (0%, 27%, 41%, and 100%). Protein sources, such as brewer's spent grain and yeast, were used in TP27 and TP41 diets to ensure equal protein contents to the control diet. Results showed no different for larval and pupal weights between diets; however, the time of development significantly increases in TP100 compared to all diets. The feed conversion rate progressively increases from 2.7 to 4.3, respectively, from the control to the TP100 diet. Conversely, lycopene and β-carotene increase in the larvae. The fatty acid composition improves by increasing polyunsaturated fatty acids (mainly α-linoleic acid). Although the best nutritional quality was obtained in T100, the TP41 is the optimal diet for balance between larval performance and qualitative improvement of larvae. Therefore, tomato pomace is suitable for the formulation of mealworm diets, even in high dosages, when supplemented with sustainable protein and carbohydrate sources. [ABSTRACT FROM AUTHOR]

Simple Summary: In recent years, there has been a resurgence of interest in silica-based powders as a non-chemical alternative for safeguarding stored food grains from stored product insects. Previous research has indicated that the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), displays a higher tolerance to inert dusts. Nevertheless, the effectiveness of the inert dusts may be influenced by their elemental composition and physical characteristics. To investigate this further, we conducted contact tests in concrete arenas to evaluate the efficacy of two amorphous silica powders, labeled as silica powder 1 and silica powder 2, which were obtained from Imery's Chemicals in Lompoc, CA, USA. Our findings revealed that exposing T. castaneum adults to silica powder 1, characterized by smaller particle sizes, was significantly more successful in inducing adult mortality and inhibiting the production of adult progeny at lower test concentrations compared to silica powder 2. Our results highlight the potential of these silica powders as a valuable tool for the control of T. castaneum for treating empty bin floors prior to the storage of newly harvested grains. The contact efficacy of two amorphous silica powders 1 and 2 procured from Imery's chemicals, Lompoc, CA, USA, were evaluated against the red flour beetle, Tribolium castaneum (Herbst). The efficacy of the silica two powders was evaluated by exposing 10 adults of T. castaneum to twelve different concentrations of silica powder 1 and 2 for 12, 24, 36, and 48 h. Mortality assessments were made after 14 d, and data on adult progeny production were recorded at 42 d. Complete mortality of T. castaneum was observed when adults were exposed for 36 h to concentrations of 1.5 to 5 g/m2 of silica powder 1. Conversely, in tests with silica powder 2, complete mortality was only achieved when adults were exposed for 48 h to concentrations ranging from 0.75 to 5 g/m2. Silica powder 1 exhibited greater efficacy in inhibiting adult progeny production in T. castaneum, particularly at a concentration of 2.0 g/m2 after 24 h exposure. Overall, silica powder 1 displayed superior performance in terms of adult mortality and the suppression of T. castaneum adult progeny production. This advantage can be attributed to the smaller particle size of silica powder 1 when compared to silica powder 2. [ABSTRACT FROM AUTHOR]

Simple Summary: Lateralization in mating behavior seems to be a common feature among insects, including some pest species. The poultry pest, Alphitobius diaperinus, has a mating behavior and success that is affected by the interplay between its sexual identity and sexual experience. Although it is expected that the directionality of the displacement (i.e., lateralization and non-lateralization) during the mating display affects the mating success in A. diaperinus, it is unknown whether this is the case. In the present study, we evaluated how lateralized and non-lateralized movements of A. diaperinus adults affect mate success in relation to the sex and sexual experience of the mating pairs. The study highlights the impact of lateralization in mating behavior and the superior skills of experienced males to achieve mating success, which seems to be related to beetle learning. Our study addresses the importance of learning in improving beetle fitness and contributes to the growing understanding of lateralized behavior on insect mating behavior. This finding enhances our comprehension of these pests, potentially contributing to the eventual mitigation of their infestation within the poultry facility. In the present study, we explored the effects of displacement directionality in mating behavior (i.e., lateralized and non-lateralized movements) on mating success (i.e., copulation occurs) and efficiency (i.e., time length at which copulation is achieved), and its association with sex and sexual experience in A. diaperinus. To do so, we carried out mating experiments and recorded the behavior of the mating pair during the whole mating sequence (i.e., precopulatory and copulatory phases). During the precopulatory phase, independently of sex and sexual experience, all beetles performed non-lateralized (i.e., backside or frontside) approaches; however, only sexually experienced beetles showed lateralized approaches (i.e., right-side and left-side). Notably, experienced males exhibited greater mating success than virgin males. After the approach, both virgin and experienced males displayed lateralized and non-lateralized mounts on the females with distinct mating success. Regardless of their sexual experience, 100% of successful mating attempts were achieved when males mounted from the females' right side. Furthermore, the development of lateralized approaches and mounts reduces the time of mating sequence span compared with non-lateralized behaviors. We highlight the importance of lateralization in mating behavior and sexual experience to achieve higher mating success, addressing a potential learning ability of beetles based on experience. [ABSTRACT FROM AUTHOR]

Simple Summary: This study evaluated the minimum as well as the maximum label dose of d-tetramethrin plus acetamiprid applied on plastic, glass, metal, wood, and ceramic surfaces, against adults of both species, in terms of immediate and delayed mortality. All T. molitor died after a 7-day exposure to the maximum dose at all tested surfaces when food was absent. In the presence of food, only glass-, metal-, and ceramic-treated surfaces killed all adults at the same dose. Even the minimum dose provided 100% mortality on glass, metal, and ceramic surfaces in both food scenarios. In the case of A. diaperinus, only the maximum dose caused the death of all exposed individuals on glass (with food) and on glass and plastic (no food). Overall, the maximum dose of d-tetramethrin plus acetamiprid is effective against the tested species on certain types of surfaces. Tenebrio molitor L. (Coleoptera: Tenebrionidae) and Alphitobius diaperinus Panzer (Coleoptera: Tenebrionidae) are two common tenebrionids occurring in grain storages. In this study, we assessed the immediate and delayed mortalities caused by d-tetramethrin plus acetamiprid on five different surfaces, i.e., plastic, glass, metal, wood, and ceramic, against adults of the two species. The tests included two label doses of the insecticide (minimum and maximum) and two food scenarios (food and no food). Generally, the maximum dose was more efficient than the minimum dose, and the presence of food resulted in lower observed mortalities than when food was absent. Tenebrio molitor was more susceptible than A. diaperinus, at all dose, food, and surface scenarios. At delayed bioassays, both doses killed all T. molitor on plastic, while on wood, mortality ranged between 80.6 and 100.0%, regardless of the food scenario. Concerning A. diaperinus, delayed mortalities ranged among treated surfaces, food scenarios, and dose from 58.3 to 100.0%. The insecticide killed the most individuals when it was treated on glass, while when it was applied on wood caused the death of the least individuals. Concerning plastic, metal, and ceramic surfaces, no general trend was observed. The maximum dose of the tested insecticide provides elevated mortalities for both species when food is absent. [ABSTRACT FROM AUTHOR]

Simple Summary: We used the geometric morphometrics method to explore whether the exposure of the parental females to pirimiphos-methyl at short exposure times may impact the wings of the F1 generation of Rhyzopertha dominica, Prostephanus truncatus, and Tenebrio molitor. For this purpose, adult females of the three coleopterans were exposed to treated concrete at the label dose for 30 min, 3, 5, 8, 16, 24, and 36 h. Their offspring responded differently to pirimiphos-methyl. The most noticeable deformations were observed in the elytra and hindwings of T. molitor, and males experienced deeper morphological changes than females. The hindwings of P. truncatus exhibited morphological deformations after 36 h of exposure to pirimiphos-methyl. Rhyzopertha dominica proved the least susceptible species since pirimiphos-methyl did not have any effect on both elytra and hindwings. Tenebrio molitor L. (Coleoptera: Tenebrionidae), Prostephanus truncatus (Horn), and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) are noxious insect pests of grains in storages. Pirimiphos-methyl is widely used to protect grains at the post-harvest stage. However, the sub-lethal impact of this active ingredient on the offspring of all three coleopterans remains unknown. Thus, mated females of each species were exposed separately to pirimiphos-methyl at short exposures (30 min, 3, 5, 8, 16, 24, and 36 h), where the elytra and hindwings of the adult progeny were analyzed with the geometric morphometrics method. Males and females of all species were incorporated into the analysis. The results revealed variability among species. Tenebrio molitor was the most sensitive among three species, displaying significant deformations in the elytra and hindwings. Males had more conspicuous morphological changes than females. Prostephanus truncatus hindwings exhibited deformities after 36 h of exposure to pirimiphos-methyl. In contrast, R. dominica offspring were not affected by pirimiphos-methyl. In light of our findings, organophosphorus insecticides may cause variable sub-lethal effects to stored-product insects. This issue may lead to different insecticidal treatments according to the targeted stored-product species. [ABSTRACT FROM AUTHOR]

Simple Summary: A model beetle, Tribolium castaneum, carries a positive single-stranded RNA virus Tribolium castaneum iflavirus (TcIV). This study shows that the TcIV is prevalent among different laboratory cultures, different strains, and the same strain maintained in different laboratories, and in the Tribolium cell line TcA. Transovarial transmissions and their prevalence in the nervous system were supported in this study. The novel TcIV, showing no observable pathogenicity, offers an opportunity to study the interaction between the virus and the immune system in this model beetle species. Iflavirus is a group of viruses distributed mainly in arthropod species. We surveyed Tribolium castaneum iflavirus (TcIV) in different laboratory strains and in Sequence Read Archives (SRA) in GenBank. TcIV is highly specific to only T. castaneum and is not found in seven other Tenebrionid species, including the closely related species T. freemani. The same strains from different laboratories and different strains displayed largely different degrees of infections in the examination of 50 different lines by using Taqman-based quantitative PCR. We found that ~63% (27 out of 43 strains) of T. castaneum strains in different laboratories are positive for TcIV PCR with large degrees of variation, in the range of seven orders of magnitude, indicating that the TcIV is highly fluctuating depending on the rearing conditions. The TcIV was prevalent in the nervous system with low levels found in the gonad and gut. The transovarial transmission was supported in the experiment with surface-sterilized eggs. Interestingly, TcIV infection did not show observable pathogenicity. TcIV offers an opportunity to study the interaction between the virus and the immune system of this model beetle species. [ABSTRACT FROM AUTHOR]

Simple Summary: Growing insects on agricultural wastes is an approach to reduce the amount of waste produced by farming operations and convert it into valuable products such as protein (for food and feed) and fertilisers. The larvae of two insects were fed with substrates that contain hemp residues (welted flowers, old leaves, and stalks) and were able to grow. The produced black soldier fly larvae did not contain the psychoactive ∆-9-tetrahydrocannabidiol (∆9-THC) and contained beneficial cannabinoids such as cannabidiol (CBD), and the amounts were minimal in comparison to the amount found in the initial substrate before given to the larvae. Mealworms were grown on hemp material that is rich in bioactive compounds, none of which was detected in the produced larvae. This study demonstrates that hemp agricultural wastes can be used as feed for these two insects, and the produced larvae do not contain the psychoactive compounds of hemp. The proper treatment of cannabis agricultural wastes can reduce the environmental impact of its cultivation and generate valuable products. This study aimed to test the potential of cannabis agricultural wastes as a substrate for the rearing of black soldier fly larvae (BSFL) and yellow mealworms (MW). In the case of BSFL, replacing the fibre component (straw) in the substrate with the hemp waste can increase the nutritional value of the substrate and led to bigger larvae. The bigger larvae had lower P and Mg, and higher Fe and Ca. Crude protein also varied based on the size of larvae and/or the content of protein in the initial substrate, which was boosted by replacing straw with hemp material. No other cannabinoids than cannabidiolic acid (CBDA), cannabigerolic acid (CBGA), and cannabidiol (CBD) were found in significant amounts in the larvae. In the case of MW, the larvae grew less on the hemp material in comparison to wheat bran. Replacing wheat bran with the hemp material led to smaller larvae with higher Ca, Fe, K, and crude protein content, but lower Mg and P values. No cannabinoids were detected in the MW fed with the hemp material. [ABSTRACT FROM AUTHOR]

Simple Summary: Essential oils (EOs) from plants are promising products for pest management. This paper describes the chemical composition and repellent action of four EOs against Ulomoides dermestoides, a common pest on several stored products. Most abundant chemical components found in the EOs were sabinene, trans-β-caryophyllene, and α-humulene for phellandrene-rich Lippia origanoides; limonene and carvone for carvone-rich Lippia alba; geranial, geraniol, and neral for citral-rich Lippia alba; and α-guaiene, α-bulnesene, and patchoulol for Pogostemon cablin. The repellent bioactivity, carried out utilizing the area preference method, showed that all EOs displayed great repellency with low mortality rates, suggesting these natural mixtures can be used in formulations of repellents against stored grain pests. The essential oils (EOs) from bioactive species can provide an alternative tool for the management of stored grain insects that is less environmentally damaging than synthetic chemicals. The aim of this study was to assess the repellent action and toxicity of EOs obtained from phellandrene-rich Lippia origanoides, carvone-rich Lippia alba, citral-rich L. alba, and Pogostemon cablin aerial parts on adults of Ulomoides dermestoides. These EOs were isolated by hydrodistillation and characterized by gas chromatography coupled to mass spectrometry (GC-MS). The repellency assay was carried out using the area preference method, and the toxicity evaluated utilizing a filter paper contact test. The major components (>10%) of the studied EOs were sabinene (16.9%), trans-β-caryophyllene (18.6%) and α-humulene (10.1%) for phellandrene-rich L. origanoides EO; limonene (40.1%) and carvone (37.7%) for carvone-rich L. alba EO; geranial (24.5%), geraniol (19.0%), and neral (11.9%) for citral-rich L. alba EO; and α-guaiene (13.3%), α-bulnesene (15.7%), and patchoulol (35.3%) for P. cablin EO. All EOs displayed 100% repellency at a concentration of 16 μL/mL, with lower toxicity than that elicited by the commercial repellent DEET. EO concentrations up to 8 µL/mL did not induce any mortality on the beetle. These findings show that the EOs provide active and safe molecules for natural repellent formulations to prevent and control insect infestations of stored products. [ABSTRACT FROM AUTHOR]

Simple Summary: The Tibetan Plateau is the largest and highest plateau in the world. The Tibetan Plateau is widely considered as a large natural experimental area for speciation; its uplift has facilitated allopatric speciation and diversification since the Miocene. In general, the Tibetan Plateau is known for its large number of endemic species. In this study, we revise the systematics of the endemic Tibetan genus Nalepa Reitter, 1887 (Blaptini tribe) and describe six new species based on larval and adult morphology and molecular data. We also provide a diagnostic key to the members of the genus Nalepa. Larvae were associated with the adults using a combined molecular species delimitation, and adult males and females are described and illustrated. Phylogenetic relationships of the members of the genus Nalepa are provided and discussed based on fragments of the mitochondrial and nuclear markers. Further, we applied molecular species delimitation methods to verify the taxonomic status of the new species. Lastly, the status of the genus Nalepa from the Tibetan Plateau is briefly discussed. Nalepa Reitter, 1887 is a monotypic genus of the tenebrionid tribe Blaptini and is endemic to the Tibetan Plateau. In this study, the genus Nalepa was reviewed using a combination of molecular and morphological datasets. Based on the results, six new species were described: N.acuminatasp. n., N. ovalifoliasp. n., N.politasp. n., N. quadratasp. n.,N.xinlongensissp. n., and N.yushuensissp. n. In addition, the larvae of N. cylindracea Reitter, 1887 and N. quadratasp. n. were described and associated with related adults using molecular approaches. This study provides valuable molecular and morphological data for phylogenetic studies. [ABSTRACT FROM AUTHOR]

Simple Summary: Tenebrionoidea, with more than 30,000 described species and 30 currently recognized families, is a superfamily of difficult taxonomy. The aim of this work is to support the basal position of the Mordellidae among the beetle tenebrionoids. They have a low number of sperm cells per cysts, contrary to the more derived families of the group; moreover, their sperm are not distributed in two bundles at the opposite poles of the cysts, as occurs in the higher taxa, but their sperm flagella form a loop in the median region so that sperm nuclei are positioned close to the tail end. The sperm structure of two members of higher families, Oedemeridae and Tenebrionidae, are investigated to confirm the data mentioned above. The sperm looping, which also occurs in the closely related Ripiphoridae, could be the consequence of the growth asynchrony between the cyst size and the sperm length. The Mordellidae sperm are characterized, not by small mitochondrial derivatives and accessory bodies, but by a peculiar stiff and immotile thin flagellar posterior region provided with only accessory tubules. The sperm ultrastructure of a few representative species of Tenebrionoidea was studied. Two species belong to the Mordellidae (Mordellistena brevicauda and Hoshihananomia sp.), one species to Oedemeridae (Oedemera nobilis), and one species to Tenebrionidae (Accanthopus velikensis). It is confirmed that Mordellidae are characterized by the lowest number of spermatozoa per cyst (up to 64), a number shared with Ripiphoridae. In contrast, in the two other families, up to 512 spermatozoa per cyst are observed, the same number present, for example, in Tenebrionidae. Also, as in the other more derived families of tenebrionoids studied so far, during spermatogenesis in O. nobilis and A. velikensis, sperm nuclei are regularly distributed in two sets at opposite poles of the cysts. On the contrary, the Mordellidae species do not exhibit this peculiar process. However, during spermiogenesis, the bundles of sperm bend to form a loop in their median region, quite evident in the Hoshihananomia sp., characterized by long sperm. This process, which also occurs in Ripiphoridae, probably enables individuals to produce long sperm without an increase in testicular volume. The sperm looping could be a consequence of the asynchronous growth between cyst size and sperm length. The sperm ultrastructure of the Mordellidae species reveals that they can be differentiated from other Tenebrionoidea based on the shape and size of some sperm components, such as the accessory bodies and the mitochondrial derivatives. They also show an uncommon stiff and immotile posterior flagellar region provided with only accessory tubules. These results contribute to a better knowledge of the phylogenetic relationship of the basal families of the large group of Tenebrionoidea. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, we used etofenprox, deltamethrin, and the combination of piperonyl butoxide+acetamiprid+d-tetramethrin as surface treatments on concrete (with or without food) to evaluate the short- and long-term mortalities of the lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) small and large larvae. Concerning short-term mortality, etofenprox killed 97.8% and 80.0% of the small and large larvae, respectively, 7 days post-exposure on concrete without food. Deltamethrin caused complete (100.0%) mortality to small larvae without food (3 days post-exposure), small larvae with food, and large larvae without food (5 days post-exposure), and 98.9% mortality to large larvae with food after 5 days of exposure. Piperonyl butoxide+acetamiprid+d-tetramethrin killed all small larvae without food 5 days post-exposure. Concerning long-term mortality, all small larvae exposed to etofenprox died on concrete without food, while piperonyl butoxide+acetamiprid+d-tetramethrin caused 85.0% mortality to small larvae on concrete with food. Overall, deltamethrin was the most efficient active ingredient for the management of both small and large larvae of A. diaperinus. The lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) is an important stored-product pest for the poultry industry as it is a vector of dangerous pathogens for humans. In the present study, we evaluated the short- and long-term mortalities of small and large larvae of A. diaperinus when they were exposed to concrete-covered Petri dishes treated with etofenprox, deltamethrin, and the combination of piperonyl butoxide+acetamiprid+d-tetramethrin. Small and large larvae were exposed to each insecticide applied on concrete surfaces with or without food. The short-term mortality was recorded after 1 day, 3 days, 5 days, and 7 days, while the long-term mortality was recorded 7 days after the transport of the larvae alive to pesticide-free concrete-covered dishes. Regarding short-term mortality levels, 97.8% and 80.0% of the small and large larvae, that were exposed to etofenprox without food, died after 7 days of exposure, respectively. Concerning deltamethrin, all tested small larvae were killed after 3 days (without food) and 5 days (with food) of exposure. For large larvae, deltamethrin caused 98.9% (with food) and 100.0% (without food) mortality levels after 5 days of exposure. The combination of piperonyl butoxide+acetamiprid+d-tetramethrin caused high mortality levels to small larvae, i.e., 84.4% and 100.0% on dishes with and without food, respectively, but low to moderate mortality levels to large larvae that did not exceed 67.8% after 7 days of exposure. Long-term mortality varied vastly among the tested insecticides. Etofenprox killed 100.0% of the small larvae on concrete without food, but 24.0% of the large larvae exposed to concrete containing food. Deltamethrin did not provide long-term mortality to large larvae when food was present. Piperonyl butoxide+acetamiprid+d-tetramethrin caused mortality rates that overall varied from 33.5% (large larvae on concrete with food) to 85.0% (small larvae on concrete with food). In conclusion, deltamethrin killed almost all exposed larvae at exposures of ≤5 days, regardless of their size and the presence of food on the concrete. [ABSTRACT FROM AUTHOR]

The insect growth regulator methoprene can be mixed into the matrix used to comprise bags and other packaging materials. Different methodologies were utilized to evaluate the efficacy of different types of methoprene-treated packaging towards Tribolium castaneum (Herbst), the red flour beetle, and T. confusum Jacquelin duVal, the confused flour beetle, two common insect species that infest stored products. Tests were conducted by creating arenas in which larvae were exposed on the packaging surface along with a flour food source, and assessments were made on adults emerging from the exposed progeny. Tests were also done by exposing adults, again with a flour food source, removing the adults after one week, and assessing adult emergence of progeny from those parental adults. In tests with larvae exposed on methoprene-treated birdseed bags, the outside surface had more activity compared to the inside surface, especially on T. confusum. In other studies with different types of packaging materials, there was generally 100% inhibition of adult emergence of exposed larvae or of progeny adults when parental adults were exposed on the methoprene-treated packaging. The best technique for evaluation was to expose late-stage larvae as the test life stage. Results show the potential of using methoprene-treated packaging for bagged storage of processed grains and grain products. [ABSTRACT FROM AUTHOR]

Entomopathogenic fungi can regulate insect populations. They have extracellular enzymes that degrade cuticle components, mainly hydrocarbons, used as an energy source. The increase in insecticidal activity of fungi in a medium supplemented with cuticular hydrocarbons was assayed and the hydrolytic enzyme profiles of two strains of Purpureocillium lilacinum were evaluated. A spore suspension of P. lilacinum was inoculated in Petri plates with different values (0.99-0.97-0.95) of water activity (Aw) using the substrates gelatin, starch and tween-20. Growth rate on the different substrates and the enzymatic activity index for proteases, amylases and lipases at different incubation times, pH and Aw, was evaluated. Moreover, the insecticidal efficiency of strains grown in media supplemented with n-hexadecane and n-octacosane was analyzed. LT50 was calculated against adults of Tribolium confusum and showed that mortality increased about 15% when the strains grew in amended culture medium. High amylolytic activity was detected, but proteases were the main enzymes produced. Optimal protease production was observed in a range of acid and alkaline pH and lower Aw. The greatest growth rate was obtained in presence of gelatin. Lipase and amylase production was detected in small amounts. Fungal growth in media with hydrocarbon mixtures increased the pathogenicity of the two strains of P. lilacinum, with the strain JQ926223 being more virulent. The information obtained is important for achieving both an increase in insecticidal capacity and an understanding of physiological adaptation of the fungus. [ABSTRACT FROM AUTHOR]

Simple Summary: Young oceanic islands often harbour poor biodiversity because they need time to be colonised. However, some animal species can be abundant, presenting high densities and being widely distributed through different altitudinal habitats of high oceanic islands. This is the case of the darkling beetle Pimelia laevigata costipennis Wollaston, 1864 on El Hierro, the westernmost island of the Canary archipelago. Therefore, this kind of framework is ideal for studying the variation of one insect species in body size, reproductive strategies, and populations in different environments. This study shows how environmental factors related to rainfall and temperature affect the different populations of this flightless beetle. Furthermore, in the more favourable habitats, located at higher altitudes, these beetles were larger in body size, laid clutches with smaller eggs, the reproduction occurred later, and showed the highest population in abundance. Lastly, this is the first study that assesses the changes of an insect along a whole insular altitudinal gradient, demonstrating apparent modifications to each habitat condition. Insects show remarkable phenotypic plasticity in response to changing environmental conditions. The abiotic factors that determine their phenotypes often vary in time and space, and oceanic islands harbour ideal environments for testing predictions on this matter. The ubiquitous beetle Pimelia laevigata costipennis Wollaston, 1864 (Tenebrionidae) is distributed over the entire altitudinal gradient of the island El Hierro (Canary archipelago), from 0 to 1501 m above sea level. Here, we examine how environmental factors (i.e., rainfall and temperature), associated with the altitudinal gradient, affect the body size, reproductive phenology, clutch size and egg volume, and population dynamics of this ectothermic flightless insect. Pimelia l. costipennis populations inhabiting upland localities, typified by lower temperatures, and greater precipitation and vegetation cover, were larger in body size and laid larger clutches with smaller eggs than those in the lowlands. Moreover, reproduction occurred earlier in the year at lower sites and later at higher sites, whereas activity density was highest in the uplands where it increases with temperature. This study first explores the changes in life history patterns along a whole insular altitudinal gradient, and finds interpopulation plasticity. It confirms that environmental factors associated with species spatial distribution act additively as drivers of phenological and phenotypic expression. [ABSTRACT FROM AUTHOR]

Simple Summary: The Namib Desert has a large diversity of darkling beetle species. All these beetles are flightless and feed on plant detritus. The aim of this study was to investigate whether the respiration strategies used by these beetles are linked to their ecology and behaviour. Three beetle species, which are all active during the day, in direct sunshine, running across the sand surface, but found in different parts of the desert, were chosen for this study. All three beetle species used intermittent breathing. They held their breath for several minutes and released CO2 in pulses. The large beetle species, which runs rapidly on the dune slip face when air temperatures are high, used evaporative cooling to prevent over-heating. The water used in the cooling comes from their respiratory surfaces and is replenished from metabolising food and drinking water droplets left on vegetation after a fog event. The two smaller beetle species, which inhabit the gravel plains, limit the area of the respiratory surface exposed to the atmosphere, which reduces body water loss. These two beetle species are not known to drink water, and thus have a greater need to conserve their body water. The respiratory physiology of three diurnal ultraxerophilous tenebrionid beetles inhabiting either the dune slipface or gravel plain in the Namib Desert was investigated. The role of the mesothoracic spiracles and subelytral cavity in gas exchange was determined by flow-through respirometry. All three species exhibited the discontinuous gas exchange cycles with a distinct convection based flutter period and similar mass specific metabolic rates. There was variation in their respiration mechanics that related to the ecology of the species. The largest beetle species, Onymacris plana, living on the dune slipface, has a leaky subelytral cavity and used all its spiracles for gas exchange. Thus, it could use evaporative cooling from its respiratory surface. This species is a fog harvester as well as able to replenish water through metabolising fats while running rapidly. The two smaller species inhabiting the gravel plains, Metriopus depressus and Zophosis amabilis, used the mesothoracic spiracles almost exclusively for gas exchange as well as increasing the proportional length of the flutter period to reduce respiratory water loss. Neither species have been reported to drink water droplets, and thus conserving respiratory water would allow them to be active longer. [ABSTRACT FROM AUTHOR]

Simple Summary: Programmed cell death is a universal mechanism in animal development and tissue maintenance, which facilitates the elimination of surplus or poorly functioning cells. Many conserved regulators of programmed cell death have been identified in model organisms including the fruit fly Drosophila melanogaster. In the latter, the four members of the RHG gene family function as critical inducers of programmed cell death. Despite this important role, RHG genes had thus far only been found in a surprisingly small number of insect groups, i.e., other flies and butterflies. This study reports the much deeper conservation of RHG genes in winged insects, ranging from cockroaches to beetles. In addition to opening new opportunities to study programmed cell death in a wide range of insects, the bioinformatic search strategy developed for this work will be of general use for studying gene families with challenging sequence evolution dynamics. Together with sickle (skl), the Drosophila paralogs reaper (rpr), head involution defective (hid), and grim (RHG) control a critical switch in the induction of programmed cell death. RHG homologs have been identified in other dipteran and lepidopteran species but not beyond. Revisiting this issue with a "taxon hopping" BLAST search strategy in current genome and transcriptome resources, I detected high confidence RHG homologs in Coleoptera, Hymenoptera, Hemiptera, and Dictyoptera. Analyses of gene structure and protein sequence conservation revealed aconserved splicing pattern and highly conserved amino acid residues at both the N- and C-terminal ends that identify hid as the most ancestrally organized RHG gene family member in Drosophila. hid-like RHG homologs were also detected in mosquitoes, redefining their michelob_x (mx) genes as an expansion of derived RHG homologs. Only singleton homologs were detected in the large majority of other insect clades. Lepidopteran RHG homologs, however, stand out by producing an evolutionarily-derived splice isoform, identified in previous work, in addition to the newly detected hid-like isoform. Exceptional sequence diversification of select RHG homologs at the family- and genus-level explain their previous elusiveness in important insect genome model species like the red flour beetle Tribolium castaneum and the pea aphid Acyrthosiphon pisum. Combined, these findings expand the minimal age of the RHG gene family by about 100 million years and open new avenues for molecular cell death studies in insects. [ABSTRACT FROM AUTHOR]

Simple Summary: Rain seldom falls in the extremely arid Namib Desert in Namibia, but when a certain amount falls, it causes seeds to germinate, grass to grow and seed, dry, and turn to litter that gradually decomposes over the years. It is thought that such periodic flushes and gradual decay are fundamental to the functioning of the animal populations of deserts. This notion was tested with litter-consuming darkling beetles, of which many species occur in the Namib. Beetles were trapped in buckets buried at ground level, identified, counted, and released. The numbers of most species changed with the quantity of litter, but some mainly fed on green grass and disappeared when this dried, while other species depended on the availability of moisture during winter. Several species required unusually heavy rainfalls to gradually increase their populations, while others the opposite, declining when wet, thriving when dry. All 26 beetle species experienced periods when their numbers were extremely low, but all had the capacity for a few remaining individuals to repopulate the area in good times. The remarkably different relationships of these beetles to common resources, litter, and moisture, explain how so many species can exist side by side in such a dry environment. Noy-Meir's paradigm concerning desert populations being predictably tied to unpredictable productivity pulses was tested by examining abundance trends of 26 species of flightless detritivorous tenebrionid beetles (Coleoptera, Tenebrionidae) in the hyper-arid Namib Desert (MAP = 25 mm). Over 45 years, tenebrionids were continuously pitfall trapped on a gravel plain. Species were categorised according to how their populations increased after 22 effective rainfall events (>11 mm in a week), and declined with decreasing detritus reserves (97.7–0.2 g m−2), while sustained by nonrainfall moisture. Six patterns of population variation were recognised: (a) increases triggered by effective summer rainfalls, tracking detritus over time (five species, 41% abundance); (b) irrupting upon summer rainfalls, crashing a year later (three, 18%); (c) increasing gradually after series of heavy (>40 mm) rainfall years, declining over the next decade (eight, 15%); (d) triggered by winter rainfall, population fluctuating moderately (two, 20%); (e) increasing during dry years, declining during wet (one, 0.4%); (f) erratic range expansions following heavy rain (seven, 5%). All species experienced population bottlenecks during a decade of scant reserves, followed by the community cycling back to its earlier composition after 30 years. By responding selectively to alternative configurations of resources, Namib tenebrionids showed temporal patterns and magnitudes of population fluctuation more diverse than predicted by Noy-Meir's original model, underpinning high species diversity. [ABSTRACT FROM AUTHOR]

Simple Summary: Tenebrio molitor is a pest of stored grain, causing considerable damage. However, its easy maintenance makes this species also interesting as a food source and as a model for physiological, immunological, ecological and evolutionary studies. We used light and transmission electron microscopy to study the morphology of circulating haemocytes. Prohaemocytes, plasmatocytes, granular cells and oenocytoids were described based on their morphological features and staining affinity. Results are a baseline for further study aimed to clarify the structure and function of haemocytes in insects. The immunocompetence of the mealworm beetle Tenebrio molitor has been well investigated at molecular and physiological levels, but information on morphological and functional characteristics of its immune cells (haemocytes) is still scarce and fragmentary. This study provides an updated overview of the morphology of circulating immune cells from mealworm beetle adults, using light and transmission electron microscopy. Based on their affinities for May–Grünwald Giemsa stain, haemocytes were defined as either eosinophilic, basophilic or neutral. Ultrastructural descriptions allowed to detect four main cell types in the haemolymph: prohaemocytes, plasmatocytes, granular cells and oenocytoids. The morphological plasticity of haemocytes and the evidence of mitotic circulating cells, intermediate cell stages, as well as autophagic activities suggest haemocyte proliferation, turnover and transdifferentiation as constantly active processes in the haemolymph. Cytochemical tests revealed differences in the distribution of carbohydrates among cell types underling the great plasticity of the immune response and the direct involvement of circulating immune cells in the resource allocation. In addition, our results provide a detailed morphological description of vesicle trafficking, macro- and microautophagy, apoptotic and necrotic processes, confirming the suitability of T. molitor haemocytes as a model for studying evolutionarily conserved cellular mechanisms. [ABSTRACT FROM AUTHOR]

Simple Summary: Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) and Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) are major stored-product pests globally. The use of contact insecticides constitutes an option of effective management of these species. Therefore, we evaluated the activity of thiamethoxam, pirimiphos-methyl, alpha-cypermethrin, and deltamethrin for the management of E. kuehniella and T. confusum larvae on three types (plastic and paper) of storage bag materials under three exposure scenarios. In addition to typical linear regression, we introduced a binomial and quasi-binomial modeling approach to analyze our data. Thiamethoxam and pirimiphos-methyl exhibited significantly higher mortality rates on E. kuehniella and T. confusum than alpha-cypermethrin and deltamethrin. Mortality rate of T. confusum larvae was significantly higher than E. kuehniella larvae. Treatments revealed significant differences in the mortalities of both species. Our results indicate that the application of contact insecticides to storage bag materials is an efficient management tool against larvae of E. kuehniella and T. confusum. The Mediterranean flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) and the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) are worldwide spread and notorious organisms of numerous stored-products. Both species are dangerous for bagged commodities as penetrators and invaders. The aim of the current study was to examine the efficacy of thiamethoxam, pirimiphos-methyl, alpha-cypermethrin, and deltamethrin, against E. kuehniella and T. confusum larvae, on different types of storage bag materials, i.e., woven propylene, biaxially oriented polypropylene and kraft paper through a (quasi)-binomial modeling approach. The type of the tested storage bag material did not affect the mortality rates of both species when treated with the tested insecticides. Thiamethoxam and pirimiphos-methyl showed statistically significant higher mortality rates on E. kuehniella and T. confusum (beta coefficient = 0.141; p-value < 0.05) compared to alpha-cypermethrin and deltamethrin. In addition, T. confusum exhibited significantly higher mortality rate in comparison to E. kuehniella. Our results also showed that the tested doses and surface treatments had a significant effect on the mortality E. kuehniella and T. confusum larvae. Significantly higher mortality rates were recorded when larvae were exposed on bag materials having both surfaces treated or on the single treated surface than when they were exposed on the untreated surface. Our findings can be useful towards an effective management strategy against stored-product insect pests. [ABSTRACT FROM AUTHOR]

Simple Summary: The red flour beetle and several other beetle pests consume post-harvest grains and grain products, and are serious pests of flourmills. Fumigation with gaseous pesticides is commonly performed in flourmills. However, fumigation is very dangerous and expensive, and it may not be needed if pest populations are very small. This project used pheromone-baited traps to capture beetles and monitor the pest populations over a two year period in flourmill 1 and a one year period in flourmill two. Traps give information about the relative population size over time at a mill and the variation in beetle numbers across different spaces of the mill. Trapping at both mills found that beetles occurred at similar numbers of beetles per trap across all the locations in the mill, but there were large differences in numbers of beetles over time. However, fumigation did not always show elimination or large reductions in beetle populations when comparing numbers trapped before fumigation with number trapped after fumigation. Traps can therefore give information about the success of a fumigation in reducing or eliminating a pest population. Numbers of beetles caught in traps do not provide the actual density or size of pest populations in food. Analysis of data at one mill compared numbers of beetles caught in traps with numbers of beetles sifted from known amounts of flour milled at the same times. That comparison showed that beetle numbers in traps increased or decreased at the same times that beetle number in the flour also increased or decreased. This research suggests that using pheromone traps for red flour beetles and other pests provide good estimates of pest population sizes to help in decisions about pest control in flourmills. This paper reports beetle pests common to flourmills targeted during a series of trapping studies over a two-year period in flourmill 1 and a one year period in flourmill 2. Objectives were (1) use pheromone-baited traps to detect T. castaneum (Herbst) and other pest species present for their distribution over space and time, (2) monitor T. castaneum activity before and after fumigations to assess efficacy of the treatment, and (3) correlate counts of T. castaneum via trap capture against direct T. castaneum counts from samples of the milled flour to assess the value of trap data to estimate relative size of the pest population. Traps were deployed in two different flourmills over two consecutive years. T. castaneum was the most commonly trapped beetle during both years in mill 1. In mill 2, Typhaea stercorea (L.) and Cryptolestes ferrugineus (Stephens) were both captured in higher numbers than T. castaneum. In mill 1, trap capture was higher overall during Year 2 for most of the species compared with capture during Year 1, likely due to a dust cover modification made for the pitfall trap used in Year 2. Trap capture was also evaluated by location within the mills and a significant difference was found in the capture of T. stercorea during both years in mill 1. T. castaneum captures were significantly reduced following most fumigations, which used methyl bromide in milling areas and phosphine in bulk-stored finished flour. However, in most cases trap catches showed that beetle populations were not eliminated. Trap captures after fumigation suggest either that the fumigations were not entirely effective, or that full grown adult beetles were entering the mill soon after fumigation. When captures of T. castaneum from traps in two spaces of mill 1 during Year 2 were compared with counts of beetles from samples of siftings collected in the finished flour, the correlation coefficients were nearly significant for both sets of traps. [ABSTRACT FROM AUTHOR]

Simple Summary: The sawtoothed grain beetle, the red flour beetle and the rice weevil are three major stored product insects that attack different stored products worldwide. Limited chemical options are available, and eco-friendlier management strategies are needed. Low oxygen treatment can be used as an alternative method to limit chemical treatments. Therefore, we conducted nine trials in commercial nitrogen chambers with phosphine susceptible and resistant populations. The vials with insects were placed in different locations inside the chambers and mortality was recorded after the termination of each trial. The vials were kept at laboratory conditions for 65 days in order to measure progeny production. Low or no survival was recorded in all cases for all species. Moreover, progeny production was suppressed with some exceptions for some species and populations. The current study indicates that low oxygen is effective against phosphine susceptible and resistant populations and can be used as alternative method to chemicals. In this study, we evaluated nitrogen treatment on phosphine-resistant field and -susceptible laboratory populations of different stored product beetles. Nine trials were conducted in commercial nitrogen chambers with the O2 level set at 1.0%. Two different temperatures—i.e., 28 and 40 °C—and three exposure intervals—i.e., 2.5, 3 and 9 d—were used in our tests. Adults of the sawtoothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae); the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae); and the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) were used in the trials. The insects were placed in vials with different commodities per species and population, and their mortality was measured after the termination of each trial. Then, the vials were kept in incubator chambers at 25 °C and 65% relative humidity for 65 d to measure progeny production. Complete parental mortality was observed in all cases for O. surinamensis and S. oryzae, but there was some survival for T. castaneum at 28 °C and 3 d of exposure. In general, progeny production was completely (100%) suppressed, with some exceptions for all species and populations. The results indicate that low oxygen is effective for all species tested, regardless of their resistance status to phosphine, and can be further adopted as an alternative method to mitigate resistance in stored product beetles. [ABSTRACT FROM AUTHOR]

Simple Summary: Insects have been considered as an alternative to fishmeal in animal feed formulations. Current methods for mass producing them remain expensive and, although cost is not the current market driver for insect products, they remain off the main stream. One way to reduce production costs is to lower the cost of insect diets. This could be accomplished by using agricultural by-products as ingredients to formulate insect diets. In this study 20 ingredients were tested as dietary components for the yellow mealworm. Ingredients included dry potato and cabbage; the bran of wheat and rice; by-product meals from vegetable oil production; spent distiller's grains from brewery and ethanol production; and hulls of different grains. A method called self-selection was used to approach the optimal proportion of these ingredients in mealworm diets by measuring their relative consumption. Nine combinations of eight ingredients were presented to groups of mealworms while carefully measuring the relative consumption of each ingredient. Results showed that the most suitable ingredients for mealworm production were dry cabbage and potato, the bran of wheat and rice, the meals of canola and sunflower, and distilled grains from corn and barley. This information will be used to formulate and evaluate diet formulations for the yellow mealworm in future research. Nutrient self-selection was used to determine optimal intake ratios of macro-nutrients by Tenebrio molitor L. larvae. Self-selection experiments consisted of 9 combinations (treatments) of 8 ingredients, from a total of 20 choices, radially distributed in a multiple-choice arena presented to groups of 100 T. molitor larvae (12th–13th instar). Larvae freely selected and feed on the pelletized ingredients for a period of 21 days at 27 °C, 75% RH, and dark conditions. Consumption (g) of each ingredient, larval live weight gained (mg), and frass production were recorded and used to calculate food assimilation and efficiency of conversion of ingested food. The macro-nutrient intake ratios were 0.06 ± 0.03, 0.23 ± 0.01, and 0.71 ± 0.03 for lipid, protein, and carbohydrate, respectively on the best performing treatments. The intake of neutral detergent fiber negatively impacted food assimilation, food conversion and biomass gain. Food assimilation, food conversion, and biomass gain were significantly impacted by the intake of carbohydrate in a positive way. Cabbage, potato, wheat bran, rice bran (whole and defatted), corn dry distillers' grain, spent brewery dry grain, canola meal and sunflower meal were considered suitable as T. molitor diets ingredients based on their relative consumption percentages (over 10%) within treatment. [ABSTRACT FROM AUTHOR]

Simple Summary: The commercially-available traps for the red flour beetle generally have low trapping efficiency, limiting their effectiveness for accurate monitoring of the population density of this cosmopolitan pest in different storage and food processing facilities. Five new traps were developed, and their efficiency for trapping the red flour beetle was tested. These new traps have the option of operating with or without a fan. The new traps generally had higher trapping than the present commercial trap. Further exploration for use in different stored-product facilities would enhance the use of these traps while providing a better estimate of the population present. The red flour beetle, Tribolium castaneum, is an important pest of stored products. We compared an existing standard commercial trap with five experimental trap designs differing from the status quo in shape, surface texture, and in forced air capability provided by fans. We tested the five new traps and a commercial trap with T. castaneum adults with the presence/absence of air flow and the availability of either the pheromone only or both the pheromone and kairomone. Without using the fans and baited with pheromone only, these new trap designs capture beetles three to five times as efficiently as the status quo trap. Use of both pheromone and kairomone doubled the capture efficiency of the status quo trap but did not significantly affect the capture efficiency of the new trap designs, all of which captured significantly more effectively than the status quo trap. Turning on fans for forced ventilation significantly improved trap efficiency of the more effective of the newer traps compared to monitoring with both pheromone and kairomone but no fan. This study provides new insights into factors affecting trap efficiency for monitoring of T. castaneum in grain storage facilities, and suggests ways in which existing traps might be improved. [ABSTRACT FROM AUTHOR]

Simple Summary: Phosphine is one of the most widely used fumigants for the control of stored grain pests in quarantine. However, PH3 resistance to many stored pests has been reported. In this study, the fumigation activity of carbonyl sulfide was researched as an alternative fumigant to control PH3-resistant pests. In PH3 treatment, there was a clear difference in the fumigation activity of domestic strain Tribolium castaneum and resistance strain T. castaneum, but both the d- and r-strains of T. castaneum showed similar results in the carbonyl sulfide (COS) treatment. Furthermore, both PH3 and COS showed no significant difference in fumigation activity in Oryzaephilus surinamensis. Phosphine resistance is occurring among stored-grain pests worldwide. This study investigated the fumigation activity of phosphine (PH3) and carbonyl sulfide (COS) against domestic strain (d-strain) Tribolium castaneum, resistance strain (r-strain) T. castaneum and Oryzaephilus surinamensis. All developmental stages of the pests were exposed to two fumigants (PH3 and COS), and the fumigation activity according to the dose and exposure time was evaluated in a 12-L desiccator and 0.5 m3 fumigation chamber. The rice sorption rate and quality following exposure to thetwofumigants were evaluated. The mortality was 2.9% in r-strain T. castaneum, 49.5% in d-strain T. castaneum and 99.2% in O. surinamensis when 2 mg/L PH3 was used in a 12-L desiccator for 4 h. However, all pest developmental stages showed 100% mortality after 24 h of exposure in the 0.5 m3 fumigation chamber, except for the r-strain T. castaneum. A mortalityof 100% was observed in all of the r-strain T. castaneum developmental stages at an exposure time of 192 h. For COS applied at 40.23 mg/L and 50 g/m3 in the 12-L desiccator and the 0.5 m3 fumigation chamber, respectively, 100% mortality was observed across all developmental stages regardless of species and strain. The sorption of COS was 10% higher than that of PH3, but there was no significant difference in rice quality compared to that in the control. Therefore, this study suggests that COS can be used for controlling T. castaneum resistant to PH3. [ABSTRACT FROM AUTHOR]

Simple Summary: Traps are used to monitor insect pests in stored food product habitats, and information on insects trapped can be used for making control decisions in pest control programs. A special trap is used for adults of the red flour beetle, one of the most serious pests of flourmills worldwide. The red flour beetle trap is a "pitfall" design wherein a walking beetle orients to the trap, it climbs up the inclined side of the trap to the top of a cup, it then slips or walks over the edge of the cup. The beetle falls into the bottom of the cup, where it is retained and killed inside the food oil placed in the bottom of the cup. However, dusty environments can result in the pitfall trap operating poorly and not capturing beetles at an optimum level. This research showed that a dust cover can be applied to the top of a baited pitfall trap and significantly improve capture of beetles in dusty environments of a flourmill. The dust cover was incorporated into the commercial pitfall trap product and now is known as the Dome trap, which is widely used for pest management of flour beetles and other stored product insects throughout the grain and food industries in many countries. A series of laboratory and field experiments were performed to assess the responses of Tribolium castaneum (Herbst) and other stored-product beetles to pheromone-baited traps and trap components. A commercial Tribolium pitfall trap called the Flit-Trak M2, the predecessor to the Dome trap, was superior in both laboratory and field experiments over the other floor trap designs assessed at capturing walking T. castaneum. In field experiments, Typhaea stercorea (L.) and Ahasverus advena (Stephens) both preferred a sticky trap to the pitfall trap. Although the covered trap is effective at capturing several other species of stored product beetles, the synthetic Tribolium aggregation pheromone lure is critical for the pitfall trap's efficacy for T. castaneum. Although the food-based trapping oil used in the pitfall trap was not found to be attractive to T. castaneum when assayed alone, it had value as an enhancer of the pheromone bait when the two were used together in the trap. A dust cover modification made to go over the pitfall trap was effective in protecting the trap from dust, although the trap was still vulnerable to dust contamination from sanitation techniques that used compressed air to blow down the mill floors. Capture of T. castaneum in the modified trap performed as well as the standard trap design in a non-dusty area of a flour mill, and was significantly superior over the standard trap in a dusty area. T. castaneum responded in flight outside a flourmill preferentially to multiple funnel traps with pheromone lures compared to traps without pheromone. [ABSTRACT FROM AUTHOR]

Simple Summary: Lesser grain borer (LGB) and rust red flour beetle (RFB) are two common insect pests that cause severe economic damage to stored grain worldwide. Current treatments rely on chemicals, but both species have developed resistance to most of these. However, by understanding the ecology of these species in regional locations it is possible to develop more targeted pest management strategies. Therefore, we conducted a 2-year trapping study to investigate for the first time the spatial and temporal activity of these two species in a temperate region of southeastern Australia. Traps were located both on and off farms. Of the two species LGB were more common, and higher numbers of both species were found in traps close to grain storages. However, they both had a wide distribution as they were caught in all traps. Both species displayed distinct seasonal trends, with activity stopping over the colder, winter months in both years. The lack of activity is partly a response to the colder temperatures, with flight activity stopping below 14.5 °C for LGB and 15.6 °C for RFB. These results can be used to inform pest management activities such as cleaning of storages, monitoring for insects, resistance management, and site hygiene. The lesser grain borer, Rhyzopertha dominica, and the rust red flour beetle, Tribolium castaneum, are two major beetle pests commonly found infesting stored products worldwide. Both species can cause severe economic damage and their management is complicated by their potential to develop resistance to several of the limited chemical options available. However, pest management strategies can be improved by understanding the ecology of the pest insect. To determine the spatiotemporal activity of R. dominica and T. castaneum, we conducted a trapping study over two years in a temperate region of south-eastern Australia, with traps located near grain storages and fields. We captured higher numbers of R. dominica than T. castaneum, and both species were more prevalent in traps located close to grain storages. Similar and consistent seasonal patterns were displayed by both species with activity ceasing during the winter (June–August) months. We found linear correlations between maximum daily temperatures and trap catches, and minimum threshold temperatures for flight activity were 14.5 °C and 15.6 °C for R. dominica and T. castaneum, respectively. The results are discussed in relation to the ecology of these pests along with their implications for pest management. [ABSTRACT FROM AUTHOR]

Simple Summary: Evaporative water loss during metabolic gas exchange is an unavoidable cost of living for terrestrial insects. This respiratory water cost of gas exchange (the ratio of respiratory water loss to metabolic rate) is suggested to depend on several factors, such as the mode of gas exchange (convection vs. diffusion), species habitat, body size and measurement conditions. We measured this cost for a blaberid cockroach and a tenebrionid beetle using flow-through respirometry. We controlled the factors that affect respiratory water cost of gas exchange, i.e., both species are similar in their mode of gas exchange (dominantly convective), habitat (relatively moist) and body size, and were measured at the same temperature. The cockroaches showed both continuous and discontinuous gas exchange patterns, which had a significantly different metabolic rate and respiratory water loss but the same respiratory water cost of gas exchange. The darkling beetles showed a continuous gas exchange pattern only, and their metabolic rate, respiratory water loss and respiratory water cost of gas exchange were equivalent to those cockroaches using continuous gas exchange. This finding from our study highlights that the respiratory water cost of gas exchange is similar between species, regardless of the gas exchange pattern used, when the confounding factors affecting this cost are controlled. However, the total evaporative water cost of gas exchange is much higher than the respiratory cost because cuticular water loss contributes considerably more to the overall evaporative water loss than respiratory water. We suggest that the total water cost of gas exchange is likely to be a more useful indicator of species distribution with respect to environmental aridity than just the respiratory water cost. Respiratory water loss during metabolic gas exchange is an unavoidable cost of living for terrestrial insects. It has been suggested to depend on several factors, such as the mode of gas exchange (convective vs. diffusive), species habitat (aridity), body size and measurement conditions (temperature). We measured this cost in terms of respiratory water loss relative to metabolic rate (respiratory water cost of gas exchange; RWL/ V ˙ C O 2 ) for adults of two insect species, the speckled cockroach (Nauphoeta cinerea) and the darkling beetle (Zophobas morio), which are similar in their mode of gas exchange (dominantly convective), habitat (mesic), body size and measurement conditions, by measuring gas exchange patterns using flow-through respirometry. The speckled cockroaches showed both continuous and discontinuous gas exchange patterns, which had significantly a different metabolic rate and respiratory water loss but the same respiratory water cost of gas exchange. The darkling beetles showed continuous gas exchange pattern only, and their metabolic rate, respiratory water loss and respiratory cost of gas exchange were equivalent to those cockroaches using continuous gas exchange. This outcome from our study highlights that the respiratory water cost of gas exchange is similar between species, regardless of gas exchange pattern used, when the confounding factors affecting this cost are controlled. However, the total evaporative water cost of gas exchange is much higher than the respiratory cost because cuticular water loss contributes considerably more to the overall evaporative water loss than respiratory water. We suggest that the total water cost of gas exchange is likely to be a more useful index of environmental adaptation (e.g., aridity) than just the respiratory water cost. [ABSTRACT FROM AUTHOR]

Simple Summary: Tribolium castaneum is an important pest of stored products. Most studies are focused on the immediate and/or delayed mortality effects, while there are no data on the effects of insecticides on the population fitness. This study deals with the effect of chlorfenapyr on T. castaneum, investigating the cost of exposure of different developmental stages on population performance, by using life table statistics and a survival analysis method. For this purpose, eggs, larvae, and parental adult females of T. castaneum were exposed to chlorfenapyr and birth or death rates were calculated daily. The exposure of eggs and larvae to chlorfenapyr was detrimental for T. castaneum and they did not complete development. When parental females were exposed to chlorfenapyr, the progeny survival curve, biological features, as well as the life table parameters did not differ significantly compared to the control treatment. We expect these results to have bearing on the management of T. castaneum, since the repeatedly insecticidal applications could be reduced in storage facilities. Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is an important pest of stored products. Insecticidal treatment is a common practice for the control of this notorious insect pest. Most studies are focused on the immediate and/or delayed mortality effects, while there are no data on the effects of insecticides on the population fitness. This study deals with the effect of chlorfenapyr on T. castaneum, investigating the cost of exposure of different developmental stages on population performance, by using life table statistics and a survival analysis method. For this purpose, eggs, larvae, and parental adult females of T. castaneum were exposed to chlorfenapyr and birth or death rates were calculated daily. The exposure of eggs and larvae to chlorfenapyr was detrimental for T. castaneum and they did not complete development. When parental females were exposed to chlorfenapyr, the progeny survival curve, biological features, as well as the life table parameters did not differ significantly compared to the control treatment. Thus, egg hatching, larval and pupal developmental periods, female and male longevities for the control treatment, and the progeny of the females that were exposed to chlorfenapyr were 4.66 and 4.76 days, 25.85 and 25.71 days, 5.00 and 5.26 days, 87.33 and 104.22 days, and 76.87 and 91.87 days, respectively. In addition, the mean values of the net reproductive rate, the intrinsic rate of increase, the mean generation time and the doubling time for the control treatment and the progeny of the parental females which were exposed to chlorfenapyr were 14.3 and 9.3 females/female, 0.038 and 0.028 females/female/day, 1.039 and 1.029, 70.0 and 76.9 days, and 18.5 and 24.9 days, respectively. We expect these results to have bearing on the management of T. castaneum, since the repeatedly insecticidal applications could be reduced in storage facilities. [ABSTRACT FROM AUTHOR]

In community ecology, ensembles are defined as phylogenetically bounded groups of species that use a similar set of resources within a community. Tenebrionids are a conspicuous faunal component of Asian deserts, but little is known about their community ecology. We investigated if tenebrionids associated with different plant species constitute ensembles with a different ecological structure. Sampling was done with pitfall traps placed beneath the most common plant species. Tenebrionid abundance patterns were modelled by fitting rank–abundance plots. The association between tenebrionid species and plant species was tested using contingency tables. Differences in ensemble diversity were investigated by diversity profiles. All ensembles were fitted by the geometric series model. Tenebrionid species were differently associated with different plant species. Diversity profiles indicate that different ensembles have different diversity patterns, because of differences in species relative abundance. Tenebrionids form different ensembles associated with the different dominant plant species. All these ensembles are, however, characterized by similar patterns of dominance, following the "niche pre-emption" model, and a steep decline in the diversity profiles. This indicates that similar environmental conditions lead to similar insect ensemble organization, although the most abundant species may vary, which suggests a role for microhabitat selection. [ABSTRACT FROM AUTHOR]

A study of the biological features and the potential population growth between two laboratory strains of the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) from Greece and Serbia is conducted on cracked barley and cracked white rice. The results show that, at a species level, T. confusum is able to complete development on cracked barley but not on cracked white rice. Therefore, cracked white rice proves to be an unsuitable commodity for T. confusum. Larval development on cracked barley is significantly shorter for the Serbian compared to the Greek strain (37.7 and 49.7 days, respectively), but pupal development does not differ between the two strains (6.2 days for both strains). Additionally, male longevity does not differ between the Greek and Serbian strains (144.4 and 151.4 days, respectively), while female longevity is significantly shorter for the Serbian (151.7 days) compared to the Greek strain (186.6 days). Fecundity does not differ between the two strains (11.3 and 17.7 eggs/female for the Greek and the Serbian strain, respectively), whilst survival is higher for the Serbian strain on both tested commodities. The values of the net reproductive rate, the intrinsic rate of increase and the finite rate of increase on cracked barley are significantly higher for the Serbian (7.27 females/female, 0.025 female/female/day and 1.026, respectively) compared to the Greek strain (2.91 females/female, 0.014 females/female/day and 1.014, respectively). It therefore is expected that different strains of T. confusum may exhibit variable phenology as well as potential population growth. Additionally, we expect our results to have bearing on the management of this species. [ABSTRACT FROM AUTHOR]

In the current study it was investigated the suitability of semolina, cracked wheat and cracked maize as feeding commodities for the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). The pest completed its development on all tested commodities. The developmental time of larvae was lower on cracked wheat (59.6 days) and cracked maize (54.6 days) compared to semolina (72.8 days). The developmental time of pupae did not differ significantly among tested commodities, ranging from 6.2 to 6.6 days. Female and male longevities were 70.9 and 77.1 days, 92.2 and 77.9 days and 177.0 and 183.7 days, when T. castaneum was fed on semolina, cracked wheat and cracked maize, respectively. The highest fecundity (28.7 eggs/female) was recorded when T. castaneum was fed on semolina, followed by cracked wheat (2.7 eggs/female) and cracked maize (1.2 eggs/female). The prolonged adult longevity, which was observed on cracked maize, may be attributed to the absence of the cost of reproduction, due to low fecundity on this commodity. The values of the intrinsic rate of increase were 0.014 and −0.021 females/female/day when it was fed on semolina and cracked wheat, respectively, while no demographic analysis was carried out for cracked maize due to high early larval mortality and low fecundity on this commodity. The net reproductive rate and mean generation time were 6.19 females/female and 127.5 days and 0.16 females/female and 91.9 days, when it was fed on semolina and cracked wheat, respectively. Based on demographic analysis, T. castaneum population growth is favored only on semolina. We expect semolina to act as a suitable commodity for T. castaneum, while cracked wheat and cracked maize allow only its survival by acting as alternative commodities. The estimated demographic parameters of T. castaneum on the tested commodities could be used as a useful tool to predict its population outcome in storage facilities. [ABSTRACT FROM AUTHOR]

The ectoparasitoid Dastarcus helophoroides Fairmaire (Coleoptera: Bothrideridae) is an important natural enemy insect, which is artificially mass-reared and released into woodland to control medium and large longhorn beetle species. This study examined the developmental duration (days) of larvae and adult fitness (including numbers of adults emerging per host and mean body size) by exposing a single substitute host, a pupa of Zophobas morio (Coleoptera: Tenebrionidae), to different densities of D. helophoroides larvae. We showed that there was no significant effect on the rate of successful parasitism and cocoon formation, but emergence success and measures of individual adult body size (length, width, and weight) declined with increasing larval density. Larval period and cocoon period increased with larval density, while total weight of adults emerging per host increased initially before reaching a plateau. Our results suggest that a pupa of Z. morio could be successfully parasitized by a single D. helophoroides larva, but multiple D. helophoroides larvae can share one host. Excessive larval density caused intraspecific competition among D. helophoroides larvae, manifesting in extended developmental duration of immature stage and reduced fitness of adults. Furthermore, the tradeoff between the numbers of adults and body size may stabilize the population dynamics with detectable mutual interference, particularly in competing for limited host resources. These findings suggest six larvae per host would achieve the highest adult fitness and would enhance mass-rearing techniques as part of IPM strategies for longhorn beetles. [ABSTRACT FROM AUTHOR]

Resistance to the fumigant phosphine in Tribolium castaneum occurs worldwide. This study evaluated tests based on adult knockdown time, the time for a beetle to become immobile, when exposed to a high concentration of phosphine. We recorded knockdown times of beetles that remained completely still for 30 s when exposed to 3000 ppm of phosphine in a large, gas-tight glass tube. Beetles were used from 12 populations, of which six were 'susceptible' to phosphine, three were 'weakly resistant', and three were 'strongly resistant'. Knockdown times were determined for single beetles, as well as for groups of ten beetles for which the time to knockdown for either five beetles (KT50) or ten beetles (KT100) were recorded. Similar knockdown times occurred across susceptible and resistant populations. However, the KT100 tests generated conservative times for diagnosing strong vs. weak resistance. The strong resistant populations were all over 100 min with KT100, compared to 60 min or less for susceptible and weak resistant populations. Special tests on single beetles revealed higher knockdown times in insects that were deliberately disturbed compared to those without any disturbances. Work reported here suggests a knockdown test conducted on beetles in a matter of minutes or hours could help classify phosphine resistance status prior to decisions on phosphine fumigation. [ABSTRACT FROM AUTHOR]