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Walaa Ebrahim Abd El Hady,1 Ghada Ahmed El-Emam,1 Nora E Saleh,2 Marwa M Hamouda,2 Amira Motawea1 1Department of Pharmaceutics, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt; 2Department of Medical Parasitology, Faculty of Medicine, Mansoura University, Mansoura, EgyptCorrespondence: Amira Motawea, Email a_metawea@mans.edu.egBackground: Schistosomiasis is a chronic debilitating parasitic disease accompanied with severe mortality rates. Although praziquantel (PZQ) acts as the sole drug for the management of this disease, it has many limitations that restrict the use of this treatment approach. Repurposing of spironolactone (SPL) and nanomedicine represents a promising approach to improve anti-schistosomal therapy. We have developed SPL-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) to enhance the solubility, efficacy, and drug delivery and hence decrease the frequency of administration, which is of great clinical value.Methods: The physico-chemical assessment was performed starting with particle size analysis and confirmed using TEM, FT-IR, DSC, and XRD. The antischistosomal effect of the SPL-loaded PLGA NPs against Schistosoma mansoni (S. mansoni)-induced infection in mice was also estimated.Results: Our results manifested that the optimized prepared NPs had particle size of 238.00 ± 7.21 nm, and the zeta potential was − 19.66 ± 0.98 nm, effective encapsulation 90.43± 8.81%. Other physico-chemical features emphasized that nanoparticles were completely encapsulated inside the polymer matrix. The in vitro dissolution studies revealed that SPL-loaded PLGA NPs showed sustained biphasic release pattern and followed Korsmeyer–Peppas kinetics corresponding to Fickian diffusion (n< 0.45). The used regimen was efficient against S. mansoni infection and induced significant reduction in spleen, liver indices, and total worm count (ρ< 0.05). Besides, when targeting the adult stages, it induced decline in the hepatic egg load and the small intestinal egg load by 57.75% and 54.17%, respectively, when compared to the control group. SPL-loaded PLGA NPs caused extensive damage to adult worms on tegument and suckers, leading to the death of the parasites in less time, plus marked improvement in liver pathology.Conclusion: Collectively, these findings provided proof-of-evidence that the developed SPL-loaded PLGA NPs could be potentially used as a promising candidate for new antischistosomal drug development.Keywords: spironolactone, poly (lactic-co-glycolic acid), nanoparticles, Schistosoma mansoni, egg load, oogram

From a global perspective, soil pests that attack crop roots are amongst the most economically damaging persistent, and difficult to detect and control. Herbivorous insect pests living in the soil represent a significant challenge to food security given their persistence, the acute damage they cause to plants, and the difficulties associated with managing their populations. Using belowground ecology for plant protection from root herbivores, particularly in an integrated way, is a new and challenging frontier. In this respect, the main focus is on ecological mechanisms viz., root tolerance, and root resistance via direct physical and chemical defenses particularly via primary and secondary plant metabolites released into the rhizosphere (alcohols, esters, and aldehydes) underpin host-plant location and recognition with 80% having attractant properties. Thus, investigations were conducted on varietal preference and the reaction of white grub, Holotrichia serrata during 2018-19 with different sugarcane varieties at Bellad Bagewadi, Belagavi district, Karnataka, India. Among the eight sugarcane genotypes screened against H. serrata grub. CoM 265 (0.00 grubs/m²) and CoSnk 09293 (0.67 grubs/m²) recorded a lower number of eggs and grub load coupled with a higher number of roots, maximum root length and high root biomass. [ABSTRACT FROM AUTHOR]

Many insects can decide when and where to lay their eggs. In some species, mature females delay oviposition to optimize their reproductive effort in response to unfavourable environmental conditions, lack of oviposition substrates or lack of mates. This behaviour might be an adaptive decision to gain a higher return on reproductive investment or may occur nonadaptively and result in lower fitness for mothers and their offspring. However, empirical studies investigating consequences of delayed oviposition focus mostly on haplodiploid Hymenoptera, thereby limiting the generalization of findings to other haplodiploid arthropods. Here, we studied this in thrips (Thysanoptera), an insect order that has independently evolved haplodiploidy. We deprived gravid Pezothrips kellyanus females of oviposition substrates for up to 2 days and examined the consequences for early reproductive effort and offspring fitness. Irrespective of a female's mating status, delayed oviposition did not affect egg size, but it increased egg load and number of the first oviposition bout, suggesting that egg development was not interrupted by the oviposition delay and eggs were not reabsorbed. Offspring sex ratio in mated females remained unaffected. Finally, oviposition delay did not affect offspring fitness in terms of survival, development time, adult size and longevity under dehydration stress. This suggests that gravid P. kellyanus females are able to avoid physiological oviposition delay costs in their early reproductive effort. This may be important for the evolution of oviposition behaviour because the capacity to delay oviposition without physiological costs may allow females to search for mates and better oviposition sites. • In insects, gravid females can delay egg laying, yet consequences are rarely studied. • We assessed effects of oviposition site deprivation on fitness in Pezothrips kellyanus. • Early reproductive effort was not affected by the oviposition delay. • Oviposition delay did not inflict any transgenerational costs on offspring fitness. • Cost-free oviposition delays may enable females to locate better oviposition sites. [ABSTRACT FROM AUTHOR]

Female egg parasitoids must optimize their ability to find a suitable host for reproduction in a limited foraging time. Odorant cues associated with the plant–host complex play an essential role in guiding females toward the host. However, parasitoid response is not always identical within the same genotype, and it could be influenced by the environment. This phenotypic plasticity affects parasitoid behavior and morphology and is directly linked to rearing conditions. Yet, how plasticity influences olfactory responses of egg parasitoids toward plant–host odors is largely unexplored. Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) is an effective biocontrol agent of the invasive brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). Laboratory no-choice and choice tests showed T. japonicus potential to develop in eggs of non-target Pentatomidae. In Y-tube olfactometer we evaluated the olfactory responses of T. japonicus reared on different hosts toward plant–host derived volatiles associated with H. halys and two other stink bug species. Parasitoids reared on the main host H. halys positively responded only to odors from V. faba–H. halys complex. When reared on alternative hosts, T. japonicus was smaller and did not exhibit attraction to any stimuli, although egg load was only partially affected. Host-induced phenotypic plasticity should be considered when evaluating parasitoids for classical biological control.

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a major pest of wheat grown on the Northern Great Plains and Canadian Prairies of North America, causing economic losses of as much as $350 million annually. Two species that parasitize wheat stem sawfly larvae in wheat stems are Bracon cephi (Gahan) and B. lissogaster Muesebeck (Hymenoptera: Braconidae). Carbohydrate‐rich diets increase adult parasitoid longevity and reproductive parameters, enhancing their success as natural enemies. In previous studies, these species had increased longevity, egg load, and volume when fed sucrose solutions, encouraging further research on their nutritional needs. Therefore, we conducted experiments with artificial diets using adult females fed sucrose, glucose, and fructose solutions. Females were also fed these sugars in combination with a mixture of amino acids. We assessed individuals daily for longevity. Both species benefited from diets containing carbohydrates, with an increase in longevity from an average of 9 to 51 days for B. cephi, and from 6 to 34 days for B. lissogaster. Additional experiments assessed egg load and volume after 2, 5, and 10 days of cumulative feeding in B. cephi. These females produced 1.4‐fold more eggs when fed amino acids, 2.5‐fold more with sugar, and 2.7‐fold more when fed sugar with amino acids. They had a 1.3‐fold increase in egg volume when fed amino acids, 1.9‐fold with sugar, and 2.1‐fold when fed sugar with amino acids. Our study reveals the nutritional requirements of these braconid parasitoids and the benefits of nutritional sources when implementing conservation biological control strategies. [ABSTRACT FROM AUTHOR]

There are two hypotheses on egg maturation in the invasive chestnut gall wasp, Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae). That it is pro-ovigenic (most or all of its potential lifetime egg complement is mature upon emergence) or facultatively synovigenic (not all eggs are fully developed upon emergence and may be resorbed when suitable hosts are absent). These hypotheses were tested by determining the effects of adult age and food (honey) on egg maturation in D. kuriphilus wasps with no access to host plants. Egg load (the number of mature eggs per female) neither increased nor decreased with adult age in the presence or absence of honey when deprived of host plants. These findings support the pro-ovigenic hypothesis. Some eggs mature during the adult lifetime of cynipoid parasitoids even without hosts, but the cynipoid gall inducer, D. kuriphilus, is pro-ovigenic, probably due to the abundance of chestnut buds available for oviposition under natural conditions. In addition to no competition for oviposition resources, thelytokous reproduction, unintentional introduction of infested chestnut trees and escape from host-specific parasitoids in introduced countries, pro-ovigeny with a high egg load has presumably resulted in D. kuriphilus becoming a global pest of chestnuts. In addition, body length, mesosomal and metasomal lengths and widths, hind femoral length, hind tibial length, and egg load as well as egg width of this wasp were also measured. There was no variation in egg width, but all the other measurements were positively correlated with egg load. Large females of D. kuriphilus had higher egg loads than small females.

Parasitoids are important insects that are commonly released into the environment to reduce the population sizes of pest species. The lifetime reproductive success of parasitoids mainly depends on host availability and the availability of mature eggs. Consequently, it is predicted that female wasps must balance the risk of egg or host (time) limitation with maximized lifetime fecundity. Typically, synovigenic females, which continue to mature eggs throughout their lifetime, have been shown to adjust their egg production rate in response to environmental variations in host availability to reduce the risk of egg limitation. In this study, we found that in a synovigenic egg parasitoid, Anastatus japonicus (Hymenoptera: Eupelmidae), the oviposition experience of Ana. japonicus females significantly enhanced the egg load and increased the rate of mature egg production. However, in contrast to other studies, the experience of contact with a host did not significantly affect the egg load in females. This result suggests that the overall oviposition experience might induce an adjustment and accelerate egg maturation in Ana. japonicus and is likely more important in egg maturation than transitory host contract. In addition to affecting the egg load, oviposition experience influenced Ana. japonicus female reproductive behaviour, which shifted virgin female behavioural preferences from mating to oviposition and laying more eggs per clutch. Our study provides an optimal strategy for the post-oviposition release of Ana. japonicus, an egg parasitoid of several lepidopteran forest pests, to improve biocontrol effectiveness. [ABSTRACT FROM AUTHOR]

Trichogramma parasitoids are the most widely used biocontrol agents and play a crucial role in the biological control of agricultural and forest pests. Many studies have shown that Trichogramma parasitoids feeding on carbohydrate rich diet can effectively improve their egg laying capacity and longevity. However, few studies have reported the impact of carbohydrate-rich diet on the biological parameters of different species of Trichogramma parasitoids. In this study, we compared the differences between the biological parameters of four Trichogramma species (T. dendrolimi, T. chilonis, T. leucaniae and T. ostriniae) before and after feeding on carbohydrate-rich diet. The results showed that all the biological parameters of Trichogramma species improved after feed on carbohydrate-rich diet. After eclosion, T. dendrolimi had the highest egg load (51.89 eggs) followed by T. chilonis (26.86 eggs), T. ostriniae (24.71 eggs), and T. leucaniae (12.44 eggs). Trichogramma dendrolimi showed an increased trend in egg load (66.7–86.21 eggs) after feeding on carbohydrate-rich diet, followed by T. chilonis (33.12–45.56 eggs), as compared to the other three species. Furthermore, T. leucaniae and T. ostriniae benefited much less from the ingestion of carbohydrate-rich diet, as only accelerated egg maturation in T. ostriniae was observed. Most of the egg loads consisted of matured eggs, so the trend of mature eggs was the same as that of the egg load. We also tested the population parameters of the Trichogramma species using the TWOSEX-MSChart. The results showed that the Trichogramma species fed with a honey diet had higher fecundities, i.e., T. dendrolimi (146.64), T. chilonis (173.53), T. leucaniae (83.69), and T. ostriniae (80.45), than when fed with water, i.e., 78.49, 40.15, 32.45 and 35.47, respectively. T. dendrolimi and T. chilonis had a higher intrinsic rate of increase r (0.4178 d−1, 0.3933 d−1), finite rate of increase λ (1.5186 d−1, 1.4818 d−1), and net reproductive rate R0 (130 offspring, 147.4 offspring), than T. leucaniae and T. ostriniae (r = 0.3373 d−1, 0.3317 d−1; λ = 1.4011 d−1, 1.3934 d−1; R0 = 73.2 offspring, 68.1 offspring) after feeding on a honey diet. We conclude that carbohydrate-rich diet significantly enhanced the biological control efficacy of Trichogramma, but the performance differed among different species. The results of this study contribute to improving the efficient application of Trichogramma parasitoids in the field. [ABSTRACT FROM AUTHOR]

Theory predicts that egg load and foraging activity of insects should be positively related. Species that emerge with a low initial egg load and mature additional eggs as they age may limit initial foraging activity to avoid egg limitation. Similarly, females, which deplete their egg supply through oviposition, should decrease activity immediately afterwards and then increase activity as new eggs are matured.The authors used activity monitors to measure daily locomotor activity separately from exposure to host cues with the stink bug egg parasitoid, Trissolcus japonicus. The authors measured activity and egg load as newly emerged wasps aged and tested whether egg depletion from oviposition would reduce activity.Parasitoid activity increased with age in parallel with egg maturation, with both egg load and activity reaching their maximum about 6–7 days after emergence. Newly emerged wasps began activity later in the day and had lower activity intensity compared with older individuals. When given host experience, females that had laid many offspring, and had thus depleted their egg loads, unexpectedly increased their activity for up to 3 days.The present study results challenge the generally accepted positive relationship between foraging activity and egg load, suggesting that this relationship may be secondary to host patch quality. The authors provide evidence that host patch quality can influence not only within‐patch but also between‐patch foraging activity.Plastic responses in activity patterns may allow parasitoids to better exploit rich host environments while minimising foraging costs and decreasing likelihood of egg limitation in low‐quality environments. [ABSTRACT FROM AUTHOR]

The cynipoid wasp Gronotoma micromorpha (Perkins) (Hymenoptera: Figitidae) is a parasitoid of the leaf miner Liriomyza trifolii (Burgess) (Diptera: Agromyzidae). The effects of adult age and body size on egg maturation in G. micromorpha were determined. The results showed that its egg load (number of mature eggs per female) increased when offered honey, water, but not hosts for 3 or 6 days after adult emergence. However, there was no significant difference in the egg loads of 3- and 6-day-old wasps. These findings and the results of previous studies on other cynipoid parasitoids suggest that when hosts are not available, females of parasitoid Cynipoidea enhance their reproductive capacity in anticipation of a future improvement in the availability of hosts by using carbohydrates and reserves stored during the larval stage. Moreover, large female wasps had higher egg loads throughout their lifetime. Given that rapid increases in the population density of L. trifolii are commonly reported in greenhouses, the demographic data of 0- and 3-day-old G. micromorpha females fed honey, need to be compared in the future. The effects of body size on the fecundity and longevity of G. micromorpha wasps should also be determined.

The glassy-winged sharpshooter (Homalodisca vitripennis (Germar); Hemiptera: Cicadellidae: Cicadellinae) is an invasive insect that transmits the plant pathogenic bacterium Xylella fastidiosa Wells et al. (Xanthomonadales: Xanthomonadacae). While adult glassy-winged sharpshooter must feed to produce eggs, the role of nutritional status on initiating oogenesis is poorly understood. To determine the effects of glassy-winged sharpshooter nutrition on nymphal development, oogenesis, and fecundity, glassy-winged sharpshooter were reared on cowpea, sunflower, sorghum, and a mixture of the three plant species. Adults emerging from cowpea, sunflower, or plant mixture treatments had shorter development times, attained larger size, and had greater estimated lipid reserves than females reared on sorghum. In choice tests, nymphs avoided sorghum and preferentially fed on cowpea and sunflower. Adult females provisioned with a single plant species during the nymphal stage were provided with either the same host plant species or a mixture of host plant species (cowpea, sunflower, sorghum) for a 9-wk oviposition period, with 37% of females initiating oogenesis. Ovipositing females had greater juvenile hormone and octopamine levels than reproductively inactive females, although topical application of the juvenile hormone analog Methoprene did not promote oogenesis. Across nymphal diets, reproductively active females produced more eggs when held on plant mixtures than on single plant species. In choice tests, adult females were observed most frequently on cowpea, although most eggs were deposited on sorghum, the host least preferred by nymphs. Results suggest that fecundity is largely determined by the quality of the adult diet, although the stimulus that initiates oogenesis does not appear to be related to nutrition. [ABSTRACT FROM AUTHOR]

Insects exchange respiratory gases with their environment through their gas-filled tracheal system, a branched tracheal tree extending from segmental openings and terminating at fine tissue penetrating tracheoles. It was shown that the tracheal volume increases hyperallometrically with insect body size (M b), both interspecifically and across developmental stages. In this study, we used the sixfold M b variation in adult Batocera rufomaculata (Cerambicidae; Coleoptera) examining the allometry of adult tracheal volume (V tr ). We further explored the effect of sex and sexual maturity on tracheal gas conductance, testing the hypotheses that (i) larger body size and (ii) egg volume in gravid females would result in lower safety margins for tracheal oxygen transport due to structural restriction. We report a hyperallometric tracheal growth in both sexes of adult B. rufomaculata (mean mass exponent of 1.42 ± 0.09), similar in magnitude to previously reported values. Tracheal gas conductance was independent of M b and reproductive state, but was significantly higher in females compared with males. We suggest that females may have pre-adapted a higher tracheal conductance required for the higher flight power output while gravid. Lack of compliant air sacs and rigid trachea may explain how gravid females retain their V tr . However, we show that V tr outgrows thoracic dimensions with increased B. rufomaculata size. Hyperallometric growth of the giant cerambycid thoracic trachea could explain the previously reported hypometric scaling of flight muscles in B. rufomaculata , and the compromised long-distance flight performance of larger compared with smaller conspecifics. [ABSTRACT FROM AUTHOR]

Mohamud A Verjee Weill Cornell Medicine – Qatar, Qatar Foundation – Education City, Doha, QatarCorrespondence: Mohamud A VerjeeUniversity Institution Weill Cornell Medicine – Qatar Qatar Foundation – Education City, Doha P O Box 24144, QatarTel +974 4492 8504Fax +974 4492 8555Email mov2002@qatar-med.cornell.eduAbstract: Tropical diseases remain severe threats to global health with acute or chronic debility. Public health issues are regularly monitored and reported by the WHO. Conditions with high prevalence and virulence such as Schistosomiasis or Malaria still need active treatment. Advances over the decades in the treatment and management of Schistosomiasis have reduced morbidity and mortality in patients. However, poverty, adverse environments, lack of education and awareness, with parasites and vectors that can thrive if uncontrolled, remain issues for the successful global eradication of Schistosomiasis. From the disease’s discovery in 1850, the author relates historical details to its current status. Several countries previously affected, including Japan and Tunisia, have eliminated the disease while others seek the same goal. Africa remains the most severely affected continent with vulnerable women and children, although the infection persists in South America and the Far East of Asia as well. Realistic improvements for continuing health conditions are vogue and emphasized for those at risk or afflicted by the infection, illustrating success models of concerted efforts of extirpation. Constant proximity to infected water, with a parasite host, are hurdles in reducing exposure. Effective medication for acute treatment is available, and prophylaxis by vaccination is promising. Where endemic Schistosomiasis is prevalent, significant morbidity and mortality have far-reaching complications in multiple human organ systems, including irreversible pulmonary hypertension, renal, genitourinary, central nervous system conditions, and neoplasia. Two hundred and thirty million people are estimated to have contracted Schistosomiasis globally, with up to 700 million still at risk of infection, and 200,000 deaths occur annually. The disease may be more prevalent than thought after newer tests have shown increased sensitivity to pathological antigens. The author discusses infectivity risks, investigations, prognosis, treatment, and management, as well as morbidity and mortality. Keywords: cercariae, egg load, granulomas, miracidia, morbidity, mortality, schistosomulae, cestode, trematode

Abstract In variable environments, sampling information on habitat quality is essential for making adaptive foraging decisions. In insect parasitoids, females foraging for hosts have repeatedly been shown to employ behavioral strategies that are in line with predictions from optimal foraging models. Yet, which cues exactly are employed to sample information on habitat quality has rarely been investigated. Using the gregarious parasitoid Nasonia vitripennis (Walker; Hymenoptera: Pteromalidae), we provided females with different cues about hosts to elucidate, which of them would change a wasp's posterior behavior suggesting a change in information status. We employed posterior clutch size decisions on a host as proxy for a female's estimation of habitat quality. Taking into account changes in physiological state of the foraging parasitoid, we tested whether different host qualities encountered previously change the subsequent clutch size decision in females. Additionally, we investigated whether other kinds of positive experiences—such as ample time to investigate hosts, host feeding, or egg laying—would increase a wasp's estimated value of habitat quality. Contrary to our expectations, quality differences in previously encountered hosts did not affect clutch size decisions. However, we found that prior egg laying experience changes posterior egg allocation to a host, indicating a change in female information status. Host feeding and the time available for host inspection, though correlated with egg laying experience, did not seem to contribute to this change in information status.

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a serious pest that prefers fresh fruits and is native to Southeast Asia. In our study, apple cider vinegar bait traps were used to capture and monitor the population dynamics of this native pest in Wuhu City, China, from May/June 2017 to May 2018. The research was conducted at 15 locations in two fruit orchards in Wuhu. Traps caught more adults in general in a Meiling blueberry orchard than in a Xicun mixed orchard, and the highest trap counts occurred near harvest time (October). Females had more mature eggs from September to November, and the number of mature eggs declined thereafter. We found several non‐crop hosts, which can provide food and reproductive resources for D. suzukii and are common in forests and field margins. By comparing the number of captured adults in the Meiling and Xicun orchards, we found that blueberry was preferred by D. suzukii among the fruits in our search. Fruit ripening times differed among crops; therefore, fly populations moved between crop and non‐crop habitats during the year or had varying population dynamics on different crops in different seasons. The D. suzukii population and the number of mature eggs decreased in summer and winter but increased in spring and autumn. Drosophila suzukii had higher survival rates with blueberry than those with other fruits, and D. suzukii could use four non‐crop species growing around the orchards as host plants. [ABSTRACT FROM AUTHOR]

Some plant pathogens are capable of manipulating their insect vectors and plant hosts in a way that disease transmission is enhanced. Aster leafhopper (Macrosteles quadrilineatus Forbes) (Hemiptera: Cicadellidae) is the main vector of Aster Yellows Phytoplasma (Candidatus Phytoplasma asteris) in the Canadian Prairies, which causes Aster Yellows (AY) disease in over 300 plant species including cereals and oilseeds. However, little is known about the host range of Aster leafhoppers or their host-choice selection behavior in this geographical region. Several crop and noncrop species commonly found in the Canadian Prairies were evaluated as food and reproductive hosts for Aster leafhoppers through no-choice bioassays. To study possible effects of pathogen infection, AY-uninfected and AY-infected insects were used. Cereals and some noncrops like fleabane were suitable reproductive hosts for Aster leafhoppers, with numbers of offspring observed in treatments using both AY-uninfected and AY-infected insects, suggesting an egg-laying preference on these plant species. Development was similar across the different plant species, except for canola and sowthistle, where growth indexes were lower. Sex-ratios of Aster leafhopper adults did not differ among the plant species or with respect to AY infection. Potential fecundity differed across plant species and was affected by the infection status of the insect. These findings have implications for AY epidemiology and suggest that while cereals can be suitable host plants for Aster leafhopper oviposition and development, some noncrop species could act as alternate hosts for leafhoppers that migrate into the Canadian Prairies before emergence of cereal and canola crops. [ABSTRACT FROM AUTHOR]

This study examined the ovipositional behavior of Gryon pennsylvanicum Ashmead (Hymenoptera: Scelionidae) on egg masses of two squash bug species Anasa tristis DeGeer and Anasa armigera Say (Hemiptera: Coreidae) by evaluating how parasitoid density and access to nutrition influenced percent parasitism on egg masses of different sizes in laboratory tests. When three parasitoids were exposed to A. tristis egg masses with only three to five eggs, 72.7% of parasitoids became trapped in the eggs and failed to emerge successfully. These results suggest that competition between larvae within the egg may have reduced the fitness of the surviving parasitoid. Continual access to honey water did not significantly influence parasitism rates on A. armigera egg masses and only increased parasitism on A. tristis egg masses with 20–25 eggs. Overall, parasitism rates were higher on A. armigera egg masses than on A. tristis egg masses, and parasitoids were more likely to emerge successfully from A. armigera eggs than from A. tristis eggs. Parasitoids spent the same amount of time probing eggs of the two species, but they spent significantly more time drilling into A. tristis eggs than A. armigera eggs. Measurements taken using transmission electron microscopy determined that the average combined width of the epicuticle and exocuticle of the egg chorion was significantly greater for A. tristis eggs than for A. armigera eggs. This difference may account for the lower rates of parasitism and parasitoid emergence and for the increased time spent drilling into A. tristis eggs compared with A. armigera eggs. [ABSTRACT FROM AUTHOR]

The Nearctic leafhopper Scaphoideus titanus is known to be the main vector of Flavescence dorée phytoplasma (FDP), a serious disease of the grapevine in temperate European areas. Adult lifespan and oviposition rate were investigated under semi-natural conditions to assess potential fecundity of this species. Egg load was detected under field conditions in North Italy. Females lived longer than males, with a sex ratio in their favour during the late season when they are still able to lay eggs. Both sexes have a high average lifespan, females can live over 60 days whilst males over 40 days. Furthermore, 25% of the females lived over 70 days, and laid an average of 60-65 eggs. A number of approximately 70 to 130 eggs was laid by 25% females. The comparison between the egg load trend and the oviposition rate shows that both indices remain constant until September and then decrease in the following months. The presence of the vector was detected until late season in the vineyards. In fact, some females with mature eggs were collected until October 30th, whilst in seminatural condition few individuals were able to lay eggs until the end October to early November. This research shows as S. titanus biological parameters have been largely underestimated so far. A serious implication of the high longevity is the prolongation of the adult inoculation period, and a temporal expansion of the risk of infecting the vineyards no longer protected by insecticide treatments. This suggests to reconsider the phytosanitary management of the vineyards after harvesting. [ABSTRACT FROM AUTHOR]

The reproductive success of many insects is considered to be limited by two main factors: the availability of mature eggs to lay (termed egg limitation) and the time to locate suitable hosts (termed time limitation). High host density in the environment is likely to enhance oviposition opportunities, thereby selecting for higher investment in egg supply. In contrast, a shortage of food (e.g. sugar sources) is likely to increase the risk of time limitation, thereby selecting for higher allocation to initial energy reserves. To our knowledge, the combined effect of host and food availability on these optimal life‐history allocations has never been investigated. We thus modelled their simultaneous effects on a three‐dimensional trade‐off between initial investment in energy reserves, egg number and egg size, while focusing on insect parasitoids. The model was based on Monte Carlo simulations coupled with genetic algorithms, in order to identify the optimal life‐history traits of a single simulated parasitoid female in an environment in which both hosts and food are present in varying densities. Our results reproduced the simple predictions described above. However, some novel predictions were also obtained, especially when specific interactions between the different factors were examined and their effects on the three‐dimensional life‐history surface were considered. The work sheds light on long‐lasting debates regarding the relative importance of time versus egg limitation in determining insect life‐history traits and highlights the complexity of life‐history evolution, where several environmental factors act simultaneously on multiple traits. [ABSTRACT FROM AUTHOR]

Olfaction plays a key role in the location of food and oviposition resources by tephritid fruit flies. Adult females, including oriental fruit fly, Bactrocera dorsalis, can sustain egg production throughout their lives provided they obtain sufficient protein. Thus, preferential attraction to food or oviposition sites (host fruit) will depend on a fly’s particular physiological state. In this study, laboratory bioassays were conducted with mature, mated B. dorsalis (provisioned protein and sugar ad libitum) to evaluate attraction to traps baited with torula yeast versus six host fruit sources (guava, guava juice, mango, orange, Surinam cherry, or white sapote). Females that preferred fruit laid a significant number of eggs around the trap entrance (average 405 eggs/fly), while almost no eggs were laid by females that preferred yeast (0.5 and 1.3 eggs/fly on two occasions). Similar results were observed in a bioassay using headspace extracts of guava juice and torula yeast, supporting olfactory-mediated responses. When individual females were allowed to oviposit in guava juice traps 0–24 h after a choice test, 45.8% of females that chose guava juice laid eggs (average 14.7 eggs/fly), compared with 27.5% that chose yeast (average 6.5 eggs/fly). Dissections indicated that females with a preference for guava juice had an egg load 2.4 times greater than females that preferred yeast. These results suggest there is an olfactory-based behavioral switch in preference from protein to host odors when female B. dorsalis are oviposition-ready. We discuss the implications of our findings for practical behavioral management and detection programs for B. dorsalis.

The amount of waste produced by the population creates general health problems in terms of public health and hygiene. In recent years the common housefly (Musca domestica L. 1758; Dipteran: Muscidae) has been widely used in the treatment of organic wastes. This study aims to assess the effect of egg loading of the common housefly on maggot development and waste reduction. Housefly larvae were reared at four egg loads (1.25, 2.5, 5, 10 mg) under three different diets (wheat bran, millet bran, cow dung). Two-factor ANOVA (α = 0.05) was used to test the effect of two fixed factors (egg load and substrate) on larval biomass, the survival rate from egg hatching until the last larval instar, number of larvae and substrate reduction rate. The comparison of means based on Duncan’s test was performed to compare the means of the different variables measured. Principal component analysis (PCA) was used to determine the relationship between the measured variables (larval biomass, the survival rate from egg hatching until the last larval instar, number of larvae, and substrate reduction rate) on the discrimination of the egg load factor. The results showed that under the same nutritional conditions, the yield of housefly larvae, the number of larvae and the reduction of substrates increased with increasing egg load. Indeed, at each of three substrates, the rearing egg load of 10 mg resulted in the maximum larval yield, maximum number of larvae, and maximum substrate reduction rate. At this optimum load, wheat bran generated greater biomass, greater number of larvae and greater reduction of substrate compared to millet bran and cow dung. The egg load as a whole had no effect on the survival rate from egg hatching until the last larval instar, unlike substrate type. The high egg load for the survival rate (from egg hatching until the last larval instar) for millet bran was 1.25 while there was no difference for the other two substrates. These results can help to make the waste treatment process efficient with the subsequent production of a large larval biomass that can serve as added value in animal feed. The egg load of 10 mg and the wheat bran were superior respectively to the other egg load and substrates type for all parameters tested excepted for the survival rate (from egg hatching until the last larval instar). Ours study indicated that larval biomass, larval number, egg viability and substrate rate reduction of Musca domestica are affected by the egg load, substrate type and their interaction.

In variable environments, sampling information on habitat quality is essential for making adaptive foraging decisions. In insect parasitoids, females foraging for hosts have repeatedly been shown to employ behavioral strategies that are in line with predictions from optimal foraging models. Yet, which cues exactly are employed to sample information on habitat quality has rarely been investigated. Using the gregarious parasitoid Nasonia vitripennis (Walker; Hymenoptera: Pteromalidae), we provided females with different cues about hosts to elucidate, which of them would change a wasp's posterior behavior suggesting a change in information status. We employed posterior clutch size decisions on a host as proxy for a female's estimation of habitat quality. Taking into account changes in physiological state of the foraging parasitoid, we tested whether different host qualities encountered previously change the subsequent clutch size decision in females. Additionally, we investigated whether other kinds of positive experiences—such as ample time to investigate hosts, host feeding, or egg laying—would increase a wasp's estimated value of habitat quality. Contrary to our expectations, quality differences in previously encountered hosts did not affect clutch size decisions. However, we found that prior egg laying experience changes posterior egg allocation to a host, indicating a change in female information status. Host feeding and the time available for host inspection, though correlated with egg laying experience, did not seem to contribute to this change in information status. [ABSTRACT FROM AUTHOR]

Learning ability has been associated with energetic costs that typically become apparent through trade-offs in a wide range of developmental, physiological, and life-history traits. Costs associated with learning ability can be either constitutive or induced, depending on whether they are always incurred or only when information is actively learned and memorized. Using lines of the parasitoid wasp Nasonia vitripennis that were selected for fast associative learning ability, we assessed a range of traits that have previously been identified as potential costs associated with learning. No difference in longevity, lipid reserves, tibia length, egg load, or fecundity was observed between the selected and control lines. All of these traits are considered to potentially lead to constitutive costs in the setup of this study. A gradual reversal to baseline learning after two forms of relaxed selection was indicative of a small constitutive cost of learning ability. We also tested for a trade-off with other memory types formed at later stages, but found no evidence that the mid-term memory that was selected for caused a decrease in performance of other memory types. In conclusion, we observe only one minor effect of a constitutive cost and none of the other costs and trade-offs that are reported in the literature to be of significant value in this case. We, therefore, argue for better inclusion of ecological and economic costs in studies on costs and benefits of learning ability. [ABSTRACT FROM AUTHOR]

Consistent individual differences in behaviour, also called behavioural types, are often observed in animal populations and can correlate to form behavioural syndromes. Behavioural types and syndromes have consequences in various fields of ecology, from species interactions to ecosystem services, notably through the role they can play in the slow–fast life history continuum. Individuals differ in their life history strategies along this continuum according to their relative investment in reproduction or survival, and the pace-of-life syndrome (POLS) hypothesis predicts a coevolution between these life history strategies and behavioural types linked to risk taking. In this framework, the aim of our study was thus to investigate the existence of behavioural types and their links with life history traits in the parasitoid hymenopteran Venturia canescens. We considered two behaviours, exploration and activity, that are linked to risk taking and resource acquisition, and three life history traits, longevity, egg load and offspring production rate. We found consistent individual differences in both exploration and activity. However, contrary to the predictions of the POLS, the behavioural types did not correlate with each other or with the life history traits tested. We thus found no evidence of a POLS in V. canescens. However, the existence of behavioural types in female parasitoids may be of utmost importance for biological control efficiency. • We studied personality and its link to life history traits in V. canescens. • Exploration and activity are repeatable in this insect species. • Exploration and activity do not correlate to form a behavioural syndrome. • Personality traits are not linked with longevity, egg load and offspring production. • There is no evidence of a pace-of-life syndrome in V. canescens. [ABSTRACT FROM AUTHOR]

The influence of female mating status on ovarian development of the ladybird, Propylea dissecta (Mulsant) (Coleoptera: Coccinellidae), was investigated under laboratory conditions. We assessed the extent to which ovariole development was affected by mating and for that we initially created a base line by observing age specific ovariole development. Results show that the number of follicles in each ovariole increased with the age of both virgin and mated females up to the age of 3 days, thereafter, no increase in number of follicles was recorded. Ovariole width also increased with age in both virgin and mated females up to 4 days, thereafter, no increase in ovariole width was recorded. The ovariole width of mated females was significantly greater than that of virgin females. Egg maturation and the egg load started to increase at the age of 8 days in virgin females. Thereafter, it increased with increase in female age. While in mated females, immature eggs were recorded in their ovarioles from the age of 1 to 2 days. In mated females, however, the increase in the number of mature eggs per ovariole and egg load started when they were 3 days old. Egg load continuously increased with increasing female age.

An ovigeny index, which is the initial egg load divided by the potential lifetime fecundity, was developed for the parasitoid, Gronotoma micromorpha (Perkins), on the host Liriomyza trifolii (Burgess) (Diptera: Agromyzidae). The value obtained for the index was estimated to be 0.54, based on the initial egg load (mean ± SD: 41.0 ± 13.5) observed in the present study and the lifetime fecundity (75.6 ± 32.6) estimated in a previous study. Gronotoma micromorpha was previously regarded as being strictly pro-ovigenic based on daily progeny production data; however, the findings of the present study showed that this parasitoid is prosynovigenic. A 3-d cycle in daily progeny production was previously reported to occur during the lifetime of adult females (6.6 d) in this species. The present study showed that the initial egg load is nearly equal to the total number of eggs deposited in 3 d following adult emergence. Therefore, it is considered that the mature eggs stored during the pupal stage are deposited during the first 3 d after adult emergence and that egg maturation in the adult stage starts on day 1 and requires 3 d to complete in G. micromorpha. To clarify the relationship between the daily progeny production and the initial egg load, a reproductive cycle consisting of maturation, deposition, and depletion of eggs is proposed. In G. micromorpha , the reproductive cycle is considered to occur twice during the female lifetime. Furthermore, it is proposed that other prosynovigenic parasitoid species have a similar reproductive cycle. [ABSTRACT FROM AUTHOR]

This study evaluated how the size of the egg mass and the parasitoids prior exposure to eggs influenced parasitism rates by Gryon pennsylvanicum Ashmead (Hymenoptera: Scelionidae) on egg masses of two squash bug species, Anasa tristis DeGeer and Anasa armigera Say (Hemiptera: Coreidae). G. pennsylvanicum is the primary egg parasitoid of A. tristis. There were no published reports available on egg parasitism of A. armigera. In choice tests, there was no difference in host acceptance by G. pennsylvanicum of egg masses of the two squash bug species. In no-choice tests, overall parasitism rates were significantly higher on A. armigera egg masses than on A. tristis egg masses. Naive parasitoids had significantly higher parasitism rates than experienced parasitoids on egg masses of both squash bug species. In a comparison of parasitism rates of field-collected and laboratory-tested A. tristis egg masses of different sizes, parasitism rates were similar in the field and in the laboratory, with the exception of egg masses with > 25 eggs. Only 17.9% of eggs were parasitized in the laboratory, compared with 36.4% in the field. Results of this study indicate that transient egg limitation prevents G. pennsylvanicum from ovipositing in every available host egg in large squash bug egg masses. The low parasitism rate of G. pennsylvanicum on large egg masses may limit its effectiveness as a biological control agent of squash bugs. [ABSTRACT FROM AUTHOR]

1. Acceptance of hosts for oviposition is often hardwired in short‐lived insects, but can be dynamic at the individual level due to variation in physiological state determinants such as ageing and prior oviposition. However, the effect of the oviposition history of resources together with time taken to accept less preferred hosts in ageing insects has rarely been investigated. 2. The time taken by parasitic fig wasps to accept resources with different oviposition histories was recorded in order to investigate the effect of wasp physiological state and resource oviposition history on oviposition behaviour. These wasps, which differ in life‐history traits, oviposit at specific developmental stages of enclosed fig inflorescences called syconia. 3. Behavioural assays were performed with naive wasps and wasps aged with and without prior oviposition experience. Syconia at the same developmental stage but differing in oviposition history were offered in no‐choice assays and the time taken to first oviposition attempt was recorded. 4. One short‐lived pro‐ovigenic galler species exhibited a decline with age in time taken to accept a syconium for oviposition. The exact timing of the transition from non‐acceptance to acceptance of less preferred syconia was determined in terms of the proportion of elapsed life span at the transition; this occurred at 25% of elapsed life span. 5. Longer‐lived parasitoids did not show any decline in specificity despite being aged for 50% of their life span. Therefore, host quality, trophic position, egg load and age may individually affect oviposition decisions or have interaction effects. [ABSTRACT FROM AUTHOR]

In order to maximize the lifetime reproductive success of parasitoids, they should be induced to dynamically accept individual hosts that have different suitability for oviposition. Parasitoids tend to exhibit higher host-selective behavior when their egg load is limited, and are less selective if they are facing time constraints. Here, we evaluated the effects of parasitoid age on egg load, fecundity and host instar preference of a honey-fed aphid parasitoid, Aphelinus asychis Walker (Hymenoptera: Aphelinidae). Host selective experiment was conducted to measure host-preference of honey-fed A. asychis females at different ages, using the second and fourth instars of the green peach aphid Myzus persicae as their hosts. The results showed that the choice of host-instar for oviposition was significantly influenced by the parasitoid age. Honey-fed parasitoids in the age groups of 1, 5, 10 and 20 days tended to parasitize predominantly second-instar aphids, whereas 15-days old parasitoids showed no significant preference of host instars. On the other hand, host-feeding preference was not affected by parasitoid age. Parasitoid females of all ages preferred younger aphids to older aphids. This result could help evaluate the effectiveness of A. asychis for biological control of M. persicae when they encountered mixed-instar aphids in the field. In addition, the results might be helpful in assessing the host killing effects of other host-feeding parasitoids. [ABSTRACT FROM AUTHOR]

The green peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) is one of the most economically important aphid species affecting crops worldwide. Since many natural enemies of this aphid have been recorded, biological control of this pest might be a viable alternative to manage it. Selected plant species in field margins might help to provide the natural enemies with food sources to enhance their fitness. This study aimed to investigate if sweet alyssum, Lobularia maritima (L.) (Brassicaceae), is a potential food source for the parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae) and the predator Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae), and whether this flower could contribute to enhance the biological control of M. persicae. Volatiles produced by alyssum, with and without flowers, attracted both natural enemies. This attractiveness to alyssum flowers was disrupted when compared with peach shoots recently infested with a relatively low number of aphids. When aphids were absent, parasitoids exposed to alyssum survived longer than those that fed on a sugar solution or on water. In the case of the predator, alyssum flowers did not benefit longevity since the nectaries were inaccessible to females. However, our results provide evidence that A. aphidimyza would be able to feed on nectar if accessible. The floral resource did not improve the reproductive capacity of the two natural enemies, but the 10% sugar solution increased the egg load of the predator. Provision of other sugar resources, such as flowers with exposed nectaries and extra floral nectar may also be a viable option to improve the biological control of M. persicae. [ABSTRACT FROM AUTHOR]

Abstract: Mythimna separata (Walker) is a serious cosmopolitan pest. Trichogramma species have been used worldwide as biological control agents of lepidopteran pests. However, no data on the control efficiency of Trichogramma species on this pest have been reported. We evaluated the suitability of M. separata eggs for three Trichogramma species, Trichogramma dendrolimi Matsumura, T. ostriniae Pang et Chen and T. japonicum Ashmead, and compared the suitability with that of Corcyra cephalonica (Stainton) eggs. The parasitism rate, development time, emergence rate, female proportion, body size and egg load of female offspring indicated that the M. separata egg is a suitable host for the three Trichogramma species. On the other hand, the non‐emergence rate and the relationship between egg load and body size reflected that M. separata eggs are less suitable for the three Trichogramma species than C. cephalonica eggs. Egg resorption occurred in T. japonicum 4 days after emergence. [ABSTRACT FROM AUTHOR]

Abstract: Maternal rearing conditions are expected to affect fitness components of progeny so that maternal effects effectively protect offspring from environmental stressors. The objective of this study was to elucidate the interaction between maternal rearing condition, age, and offspring rearing condition in the parasitoid wasp Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae, Aphidiinae). The effects of maternal age, body size, and host instar used for development on fitness components of progeny were evaluated. Host was the black bean aphid, Aphis fabae Scopoli (Hemiptera: Aphididae). Results indicated that small and young mothers (developing in first‐instar hosts) produced progeny with a longer developmental time compared to large and old mothers (developing in second‐instar hosts). Progeny that hatched from larger eggs also had a larger body size. There were, however, no significant differences in the size of progeny that developed in different host instars. Progeny that hatched from large eggs had a higher initial egg load, and progeny produced by younger mothers had larger eggs. These differences were significant only when progeny developed in the first host instar, whereas in the second and fourth instar no differences were observed. Our findings indicate that progeny with larger size at the egg stage had superior fitness. Age‐specific maternal effects were not as strong as the effect of the mother's body size. Although the interaction between host instar of progeny development and maternal rearing condition was not statistically significant, developing in suboptimal instars led to trade‐offs between fitness components in progeny. The ecological significance of these findings is discussed. [ABSTRACT FROM AUTHOR]

The South East Asian salticid,Asemonea tenuipes, lay its eggs like an insect: as individuated capsules in geometrically precise rows. The occurrence of this behaviour is described in a population from Thailand that lays eggs on the underside of mango tree (Mangifera indica) leaves. The rows were vertically arranged at a 90° angle that was parallel to, and varied in relation to the angle of the central leaf rib, indicating that the rib serves as the primary visual cue for orienting the row. Analysis of within-egg row symmetry found evidence that micro-topography – in particular, vertical ‘stepping’ produced by leaf sub-ribs – of the leaf surface plane was responsible for 97% of variability in the relative symmetry of egg placement. Three strategies were identified: (1) crossing the sub-rib and producing localized asymmetry in the egg row; (2) introducing a gap at the sub-rib to maintain symmetry; and (3) ‘compressing’ the egg row into the gap between sub-ribs. The incidence of asymmetry showed a highly significant linear relationship with egg load. It is hypothesized that the use of rows probably represents a solution to the problem of how to surveil temporally staggered clutches of eggs and newly hatched spiderlings simultaneously. [ABSTRACT FROM AUTHOR]

Our knowledge of the main determinants of invasion success is still incomplete. Among these factors, the effects of biological traits, including fecundity, longevity and dispersal in newly colonised regions, are pivotal. However, while numerous studies have considered ecological and evolutionary impacts of non-native species, their biology often remains understudied. Despite the continuous geographic expansion of Merizodus soledadinus (Coleoptera: Carabidae) at the Kerguelen Islands over recent decades, the main life-history parameters of this species are unknown. We determined adult longevity under controlled conditions, monitored seasonal activity through pitfall trappings, and analysed temporal variations of egg load and body reserves in field-collected individuals. The median adult life span (LT) was 241 days, with maximum longevity of 710 days ( N = 500). Females carried eggs throughout the year (8.94 ± 3.56 eggs per female), and it was not possible to pinpoint any clear egg-laying period. Year-round trappings demonstrated continuous activity of adults over seasons, with a peak during the austral summer that may arguably be associated with higher temperatures. Body stores (glycogen and proteins) did not vary significantly through the year, suggesting that adults feed continuously despite different prey availability between summer and winter, possibly via diet shifts. The amount of triglycerides increased at onset of summer, which may be associated with higher summer locomotor activity and/or more intense predation and reproduction. [ABSTRACT FROM AUTHOR]

Body size is a standard criterion of quality control in insect rearing and often assumed to correlate with fitness in parasitoid wasps, but various metrics of body size can be used. The purpose of this study was to determine which morphological feature provides the best correlation with body size and egg load in a thelytokous population of the parasitoid wasp, Lysiphlebus fabarum (Marshall), when reared on Aphis fabae Scopoli under standardized conditions in a growth chamber (21 ± 1°C, 60-70% RH, and 16L : 8D). Candidate metrics included head width, length and width of the pronotum, length and width of the right forewing, and length of the right hind tibia. In the first experiment, correlations were determined between these measurements and overall wasp body length. As head width and hind tibia length emerged as the most suitable proxies for total body length, the next experiment these two variables as proxies for egg load in females reared from different nymphal instars of the host aphid. There was a non-linear relationship between body size and egg load of wasps emerging from hosts parasitized in different nymphal instars. Egg load increased linearly with body size across all host growth stages, but the second nymphal instar was the most suitable stage for parasitism when speed of development was factored in. The results suggest that head width is a suitable morphometric for monitoring quality control in mass-reared cultures of this wasp.

Torymus sinensis Kamijo is the main parasitoid associated with the Asian chestnut gall wasp Dryocosmus kuriphilus Yasumatsu. It was released as biocontrol agent in Asia and many European countries in order to contain the gall wasp outbreaks. It is reported as univoltine, but it also exhibits a prolonged diapause mainly as late instar larva. In the two-year period (2014-2015) we investigated longevity, egg load, ovigeny strategy, and body metrics of T. sinensis under laboratory conditions in order to assess the potential fecundity and the effects of age on the egg load, considering univoltine and diapausing adult wasps. T. sinensis females reached a maximum age of 102 days as univoltine and 73 days as diapausing adults. Newly emerged adult wasps contained 0.5 ± 0.31 and 0.9 ± 0.60 mature eggs in the univoltine and diapausing population, respectively. The total mean egg load (mature + immature oocytes) recorded for the univoltine females at day 0 was 215 ± 2.43 whilst for the diapausing females was 240 ± 2.31. The ovigeny index calculated for univoltine wasps was 0.0023 and 0.0041 for diapausing ones, indicating for both populations an extremely synovigenic behaviour. Except for the first two weeks, diapausing females had a higher egg load that univoltine. Univoltine males, females and their eggs showed to be significantly larger than diapausing ones. A decrease in egg load with an increase in adult female age was found in both populations, probably due to egg resorption. This study demonstrates that the aging of parasitoids plays an important role concerning the egg load, influencing the effectiveness of T. sinensis in the context of biological control programs, and suggesting that 2-3 week-old females have to be preferred during the release stage in order to maximize parasitism. Implications of these reproductive traits for the success of T. sinensis as biological control agents are discussed. [ABSTRACT FROM AUTHOR]

Fitness in parasitoids is generally influenced by host quality. We measured the effects of three tephritid host species that varied in size, the fruits they developed in, and host nutritional content on some measures of fitness such as egg load, individual egg size, body size, and nutrient composition in the braconid Diachasmimorpha longicaudata , a widely used fruit fly biological control agent. The host species were: Anastrepha ludens (large host developing in both grapefruit and an artificial diet), Anastrepha obliqua (small host) and Anastrepha serpentina (small host). Female parasitoid body size was influenced by host size and the number of eggs per female varied significantly with parasitoid age (0–24 h). Female parasitoids that emerged from A. obliqua and those that emerged from A. ludens reared in grapefruit had the largest eggs, whereas those that emerged from A. ludens reared in artificial diet and from A. serpentina had the smallest eggs. While nutrient concentrations differed among fly species, there was little to suggest that resources were more accessible in certain hosts. The largest host did not necessarily exhibit the highest nutrient concentration. Larger hosts represented larger macronutrient pools and the nutrient content of the host generally corresponded to the relative abundance of the same nutrients in the parasitoids that developed within them. Nevertheless, the quality of the various hosts tested had little effect on egg load, egg size and adult nutrient composition of the oligophagous parasitoid, D. longicaudata . This renders D . longicaudata a valuable candidate parasitoid for the biological control of multiple species of Anastrepha. [ABSTRACT FROM AUTHOR]

Drosophila suzukii is a serious pest of several fruit crop systems in California's Central Valley, which is one of the world's major fruit-growing regions. This study followed D. suzukii seasonal population dynamics in multiple cropping and riparian systems in four cherry-producing counties of the Valley. Apple cider vinegar baited traps were used to monitor D. suzukii adults weekly, from April 2013 to July 2014, in 28 fields. Results show peak captures in the spring and fall seasons. In cherry orchards, adult trap counts were the highest near harvest (June) and declined thereafter, as fly populations moved to other crop (e.g., citrus) or non-crop habitats. The number of captured adults was positively related between pairs of sampled sites based on their proximity but was negatively related to differences in fruit ripening periods between different crops, suggesting that fly populations moved among crop and/or non-crop habitats during the year or had varying population dynamics on different crops and in different seasons. Mature egg load per female was higher during the fruiting season but lower during the winter season, with the majority of winter-captured females not containing mature eggs. This survey also reports for the first time the presence of trapped D. suzukii adults bearing melanized and encapsulated parasitoids in North America, non-target captures of larval drosophilid parasitoids in the traps, as well as the occurrence of larvae in the ovaries of adult female D. suzukii. [ABSTRACT FROM AUTHOR]

Knowledge regarding the reproductive status of spotted-wing drosophila, Drosophila suzukii ( Matsumura) ( Diptera: Drosophilidae), is of critical importance in predicting potential infestations of this invasive pest, as eggs are laid in ripe or ripening fruit of several commercially important small-fruit crops. Token environmental stimuli for the induction of reproductive diapause and improved cold tolerance were identified for D. suzukii. Diapause induction was evaluated by assessing, via dissection, the number of mature eggs carried by field-captured D. suzukii and laboratory-reared D. suzukii held under various temperature and photoperiod regimes. Egg load decreased over time in females trapped from July to December at sites in Benton County, OR, and Ontario County, NY, both USA, and reached zero eggs by December at all sites. Photoperiods below 14 h of day length led to reduced egg maturation in laboratory-reared flies held at moderate temperatures (15 or 20 °C). Whereas very few mature eggs were found in females held at 10 °C under short- or long-day photoperiods for several weeks after eclosion, a spontaneous return to ovarian maturity was observed in short-day-entrained females after 7 weeks. Diapause termination was investigated by evaluating fecundity in diapausing females returned to optimal environmental conditions. Whereas long-day-entrained flies began producing offspring immediately upon return to optimal conditions, short-day-entrained flies returned after 1 and 6 weeks at 10 °C were slower to produce offspring than colony flies or short-day-entrained flies returned after 7 weeks. Cold tolerance was evaluated by observing chill coma recovery rates after 24 h exposure to −1 °C. Cold-acclimated (diapausing) females recovered from chill coma faster than cold-hardened or unacclimated females. [ABSTRACT FROM AUTHOR]

The amount of resources available during development often affects body size, causing phenotypic variation in life-history traits and reproductive behaviours. However, past studies have seldom examined the reaction norms of both life-history and behavioural traits versus body size. We measured the phenotypic plasticity of several life-history (age-specific egg load, egg size, longevity) and behavioural (oviposition rate, host marking rate, walking speed) traits of the egg parasitoid Telenomus podisi Ashmead (Hymenoptera: Scelionidae) in response to body size variation. We predicted that life-history traits would show more evidence of size compensation than behavioural traits, resulting in fewer positively-sloped size versus trait reaction norms among the former. As predicted by life-history models, smaller wasps appear to shift resource allocation towards early-life reproduction, having a similar egg load to large individuals 9 days after emergence. Surprisingly, longevity was unaffected by body size. However, egg size, the number of offspring produced during oviposition bouts, and the rate of subsequent egg synthesis were greater for larger individuals. In addition, as predicted, the reaction norms of behavioural traits versus body size were all positively sloped. Thus, despite possible adaptive compensatory plasticity of life-history traits by small individuals, behavioural constraints directly related to body size would contribute to maintaining a positive size-fitness relationship. [ABSTRACT FROM AUTHOR]

Hyssopus pallidus (Askew) (Hymenoptera: Eulophidae) is a gregarious ectoparasitoid of late larvae of the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae). In the present work reproduction and the development and morphology of the immature stages were studied. Five larval instars were differentiated by the shape and size of the mandibles. The larvae are hymenopteriform with a weakly sclerotized head and 13 segments. The first instar has four pairs of spiracles, while the other four instars have nine pairs. Under laboratory conditions of 22-24°C and 60-80% RH the egg stage lasted 1.5 days, the larval instars 6.3 days, and the pupal stage 7.9 days in females and 7.2 days in males. The duration of each of the five larval instars (L1-L5) is approximately 1, 0.5, 0.75, 0.75 and 3.5 days, respectively. Male and female development time does not differ significantly in the egg and larval stages, but differences are highly significant in the pupal stage. Male and female pupae can be differentiated by their sexual rudiments. Copulation takes place immediately upon emergence of the females between siblings, adult males appearing before the females. Females in culture with access to an energy source can survive for more than 60 days. They are synovigenic: they emerge with no mature eggs in their ovaries and take the first two days after emergence to mature the full set of around 24-30 eggs. They continue paralyzing hosts, ovipositing and maturing eggs for as long as they live. After an oviposition a female needs two to three days to mature a new full set of eggs. Age and feeding influence egg load. Oösorption is significant in starved females, but also occurs in older fed females with no host contact.

The parasitoid, Anagyrus kamali Moursi (Hymenoptera: Encyrtidae), has been recently introduced into the Caribbean as a biological control agent against the hibiscus mealybug (HMB), Maconellicoccus hirsutus Green (Homoptera: Pseudococcidae). Storage of A. kamali that is essential for its use in biological control did not affect the longevity of female and male parasitoids (40.3 ± 14.07 and 31.7 ± 9.57 days, respectively) when kept at 20 ± 2°C in absence of hosts and fed ad libitum with droplets of pure honey. At a storage temperature of 27 ± 2°C the longevity decreased by about 10 days. Fed females did not resorb eggs during the first two weeks of storage at 20 ± 2°. Parasitoid ovogenesis ceased when ovarioles/lateral oviducts were full. The lifetime fecundity was not significantly affected by a storage at 20 ± 2°C of up to 14 days. Foraging activities and oviposition were the main factors influencing the lifespan of female A. kamali.