Search

Simple Summary: Plant-derived semiochemicals have attracted considerable attention in recent years as promising attractants for the management of forest pests, mainly due to their safety and low cost. The poplar bark beetle, Trypophloeus binodulus (Ratzeburg, 1837) (Coleoptera: Scolytidae), is a serious pest of poplar trees (Salicaceae: Populus), resulting in significant economic and ecological losses across northern Spain. We tested the hypothesis that Trypophloeus binodulus is attracted to compounds released by its host-plant genus. This study tested adults of T. binodulus using electroantennography and by monitoring their populations in baited traps in northern Spain. The volatiles released by the leaves and bark of clones revealed high emissions of different chemical compounds, including benzenoids, sesquiterpenes, monoterpenes, fatty acids, and alkanes. The benzenoid salicylaldehyde dominated these collections and was more abundant in aerations of poplar leaves than in other odor sources. Field tests showed that traps baited with salicylaldehyde and ethanol captured more adults than all other treatments. These findings highlight the potential of salicylaldehyde for managing T. binodulus and developing environmentally friendly pest control strategies. The poplar bark beetle Trypophloeus binodulus (Coleoptera: Scolytidae) is a key pest of poplar trees (Malpighiales: Salicaceae, genus Populus) across northern Spain. However, among the more than 200 poplar clones available on the market, the clone USA 184-411 has the highest susceptibility to T. binodulus attacks. We tested the hypothesis that compounds released by the most susceptible poplar clone chemically mediate Trypophloeus binodulus behavior. The leaf and bark volatile chemical profile composition of host poplar Populus nigra L. (Salicaceae) clones were analyzed and tested on adult T. binodulus by electroantennography (EAG) and by monitoring their populations in baited traps in northern Spain. The collection of volatiles released by the leaves and bark of both clones by SPME revealed the emission of 53 components from different chemical classes. Salicylaldehyde dominated these collections of leaf volatiles and was more abundant in aerations of the more susceptible poplar clone (USA 184-411). The EAG response of adult beetles to salicylaldehyde was higher than that of any other plant odorants. In field trials, traps baited with salicylaldehyde + ethanol significantly captured more adults than all other treatments, irrespective of other lure components. The present study could aid in developing semiochemical-based management tactics against this important pest. [ABSTRACT FROM AUTHOR]

Seeds and seedlings are particularly vulnerable to herbivory. Unlike mature plants, which can wait until herbivory is experienced to induce defense, seeds and seedlings face mortality if they wait. Slug mucus functions as a kairomone, a non-attack-related substance emitted by consumers that is detected by a prey species (in this case, plants). While snail mucus has been shown to induce defense in seedlings, it is not widely confirmed whether slugs have the same effect and whether seeds can also detect and react to such herbivore cues. We investigated how exposure to Arion subfuscus mucus affected growth and defense in Brassica nigra seeds and seedlings. Seeds exposed to slug mucus germinated 5% faster than control (water only) seeds, but the resulting seedlings weighed 16% less than control seedlings. To test whether this difference results from herbivore-exposed plants allocating energy from growth to defense, we conducted choice bioassays assessing slug preference for control seedlings versus seedlings that were either (A) exposed to mucus only as a seed; or (B) exposed to mucus as a seed and seedling. While slugs did not differentiate between control seedlings and ones exposed to herbivore cues only as a seed, they ate 88% less biomass of seedlings exposed to mucus as both seeds and seedlings. These results suggest that slug mucus induces changes in plant traits related to defense and growth/competitive ability. Future research should determine the chemical mechanisms of this induced defense. [ABSTRACT FROM AUTHOR]

Hibiscus mealybug, Nipaecoccus viridis (Newstead) (Hemiptera: Pseudococcidae), is a recent invasive pest of citrus and many other crops in Florida. Nipaecoccus viridis attacks all above ground parts of citrus trees and heavy infestation can cause leaf drop and premature abortion of developing fruits. We quantified greater captures of N. viridis in cardboard band traps on areas of citrus trees that were intentionally injured by mechanical rasping of epidermal tissues as compared with similar but uninjured citrus branches. Direct field collection of headspace volatiles from mechanically injured or intact citrus branches revealed both qualitative and quantitative differences. Certain volatiles (γ-terpinene, citronellal, citronellyl acetate, β-E-farnesene, α-humulene, and α-E-E-farnesene) were only present in samples from damaged citrus branches. Behavioral assays using a laboratory Y-tube olfactometer revealed attraction of N. viridis to volatiles associated with mechanical damage of citrus including synthetic β-ocimene, γ-terpinene, sabinene, isomers of farnesene, and citronellal when loaded into lures at either of 2 concentrations (0.01 or 0.1 µg/µl). Subsequent field trapping experiments confirmed increased captures of various life stages of N. viridis in cardboard band traps baited with a 10.0 µg/µl concentration of farnesene:ocimene:sabinene blend (in 7:13:17 ratio), as well as those releasing either farnesene or ocimene alone at this same concentration, as compared with the mineral oil (diluent) negative control. Our results indicate that common plant related terpenes released by citrus following mechanical damage may be useful for development of an effective monitoring trap for N. viridis. Graphical Abstract [ABSTRACT FROM AUTHOR]

Environmental cues that predict increased risk of herbivory can prime plant defenses; however, few studies have explored how such cues elicit broader plant responses, including potential effects on plant growth and other resource allocations that may affect tolerance to herbivore damage. We exposed goldenrod plants (Solidago altissima) to varying concentrations of the putative sex pheromone of a gall‐inducing herbivore, which has previously been implicated in defense priming. In experiments with two plant genotypes and three herbivore populations, any level of exposure to the pheromone enhanced tolerance of galling, rescuing flower production to levels observed for ungalled plants. Exposure to low doses of the pheromone elicited greater resistance to galling than exposure to high doses, with unexposed plants exhibiting intermediate resistance, suggesting a nonlinear relationship between exposure and defense priming. These findings suggest plant responses to environmental cues associated with biotic stressors are broader and more complex than previously appreciated. [ABSTRACT FROM AUTHOR]

Mosquitoes are known to choose oviposition habitats actively based on their suitability for survival of their offspring. They thus avoid laying eggs in dangerous habitats with aquatic predators through detection of their cues. Visual, tactile, and chemical cues emitted by certain predators have been shown to reduce oviposition in some mosquitoes, which in turn may affect their adult population sizes. However, those tests tend to be limited to species from temperate regions. Moreover, mosquito oviposition response to predator cues have been shown to be predator specific, but this has not been investigated for many potential predators worldwide. In the African subtropics, temporary ponds can be important mosquito breeding habitats and the same habitats are also used by a group of specialized killifish that can survive dry periods using drought resistant eggs. Although they are reported as mosquito predators, it is unknown whether mosquitoes actively avoid laying eggs in ponds with annual killifish. We investigated this using the mosquito Culex quinquefasciatus and the free and caged killifish Nothobranchius neumanni in the outdoor mesocosm experiments in Tanzania. We found that Cx. quinquefasciatus had 71% lower oviposition in mesocosms with free swimming killifish and 68% lower oviposition in mesocosms with caged killifish. We conclude that predator-released chemical cues alone are enough to explain the observed responses. If the cues can be isolated and chemically identified can be developed into a biological mosquito control strategy and used to safeguard public health in areas where mosquito borne diseases are endemic. [ABSTRACT FROM AUTHOR]

In 2009, we determined the effects of the enantiomeric composition of the kairomone, α-pinene, on trap catches of arboreal beetles (Coleoptera) in stands of eastern pine trees with resin dominated by (+)-α-pinene. We hypothesized that the responses of beetles would correlate with the predominant enantiomer of α-pinene found in host pines. Lures of (+)-, racemic (±), and (−)-α-pinene were added separately to ethanol-baited multiple-funnel traps. Species such as Monarthrum mali (Fitch), Dendroctonus terebrans (Olivier), Ips grandicollis (Eichhoff), and Pachylobius picivorus (Germar) (Coleoptera: Curculionidae) showed a preference for traps co-baited with (–)-α-pinene. α-Pinene enhanced attraction of Hylastes salebrosus Eichhoff, Hylastes porculus Erickson and Hylastes tenuis Eichhoff (Coleoptera: Curculionidae) to ethanol-baited traps with no effects from enantiomeric composition of α-pinene. The attraction of the ambrosia beetles, Xyleborinus saxesenii (Ratzeburg) and Dryoxylon onoharaense (Murayama) (Coleoptera: Curculionidae) to ethanol-baited traps was interrupted by the addition of α-pinene, regardless of enantiomeric composition. Species such as Xylosandrus germanus (Blandford), Cnestus mutilatus (Blandford) and Stenoscelis brevis (Boheman) (Coleoptera: Curculionidae) were unaffected by the presence of α-pinene. Trap catches of some species of longhorn beetles and bark beetle predators (Coleoptera: Cerambycidae, Cleridae, Elateridae, Histeridae, and Trogossitidae) were increased by the addition of α-pinene, although results varied by location. Platysoma spp. (Coleoptera: Histeridae) showed a marked preference for traps co-baited with (+)-α-pinene in Florida and Georgia. In summary, we found that the enantiomeric composition of α-pinene in hosts was not a good predictor of enantiomeric preferences by beetles. [ABSTRACT FROM AUTHOR]

Sea urchins can strongly reduce their mobility, exposure to predation, and feeding rates upon detection of chemical cues produced by predators, driving behavioral effects on grazing activity that may contribute to macroalgal community dynamics. However, the extent of chemically induced antipredator behaviors in urchins can vary by predator–prey species pair and ecological context and is therefore important to characterize in novel settings. Additionally, the effect of predator and prey size on urchin reactions to predator cues has rarely been considered, with the few existing examples yielding mixed conclusions. Here, we used a replicated split‐plot experiment to measure the effects of red rock lobsters (Jasus edwardsii) on consumption of macroalgae by the New Zealand sea urchin (Evechinus chloroticus) across a range of predator and prey body sizes. Overall, per‐capita consumption rates of kelp by urchins declined by 30% in the presence of lobsters, though feeding activity varied widely among individuals. Based on mass‐specific measurements of feeding rates, responses to predator cues appeared similar across all urchin sizes but only yielded distinguishable differences in the amount of kelp consumed in trials with larger urchins due to their considerably higher feeding capacity. Conversely, consumption rates of kelp by urchins had no apparent relationship with lobster size, likely due to chemical cue saturation in our experimental setting or a risk gradient that was insufficient to elicit a graded behavioral response. Our findings provide new evidence for a nonconsumptive effect of lobsters on feeding rates of an important grazer that can potentially reinforce the ecological role of this key predator in New Zealand kelp beds. [ABSTRACT FROM AUTHOR]

Daphnia can avoid predation by sensing fish kairomones and producing inducible defenses by altering the phenotype. In this study, the results showed that the morphological and life‐history strategies of two Daphnia species (Daphnia pulex and Daphnia sinensis) exposed to Aristichthys nobilis kairomones. In the presence of fish kairomones, the two Daphnia species exhibited significantly smaller body length at maturity, smaller body length of offspring at the 10th instar, and longer relative tail spine of offspring. Nevertheless, other morphological and life‐history traits of the two Daphnia species differed. D. pulex showed a significantly longer relative tail spine length and earlier age at maturity after exposure to fish kairomones. The total offspring number of D. sinensis exposed to fish kairomones was significantly higher than that of the control group, whereas that of D. pulex was significantly lower. These results suggest that the two Daphnia species have different inducible defense strategies (e.g., morphological and life‐history traits) during prolonged exposure to A. nobilis kairomones, and their offspring also develop morphological defenses to avoid predation. It will provide reference for further exploring the adaptive evolution of Daphnia morphology and life‐history traits in the presence of planktivorous fish. [ABSTRACT FROM AUTHOR]

The Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), is a crop pest of global economic importance because of its wide range of hosts and its invasiveness capacities. To develop a novel integrated and sustainable crop protection, we have investigated the insecticidal properties of different varieties of kava (Piper methysticum [ Frost]) extracted by two methods and the attractive effects of six plant volatiles identified from B. tryoni host plants to female, mated or not. We did not identify any significant insecticidal effect of the traditional Pacific kava plant at the tested concentrations. Among mated females, ethyl acetate compared to the no odor control elicited the highest attraction (87%, of which 60% for this odor), while ethyl butyrate was preferred compared with ethyl acetate in dual choice assays. Flies' preferences for specific odors depended on their mating status and the odor landscape they were confronted with. Combination with the commercial ingestion insecticide (Success 4: spinosad, 480 g/l, Dow AgroSciences, Valbonne, France) with the plant volatiles were tested to detect an increase in mortality related to the addition of an attractant. The 2-heptanone slightly showed a tend to increase the attractiveness of mated females within 4-6 h to the food bait, but the results were not statistically significant after 8 h. Further tests should be performed with other concentrations or mixtures of the identified host plant volatiles to develop a strong lure and kill strategy. [ABSTRACT FROM AUTHOR]

The southern pine beetle, Dendroctonus frontalis Zimmermann is an important mortality agent of Pinus in the eastern United States of America where it commonly shares hosts with the black turpentine beetle, Dendroctonus terebrans (Olivier), which infrequently kills trees. Unlike D. frontalis , which must kill its hosts to become established in the bark and reproduce, D. terebrans can occupy living hosts as a parasite. Olfactory mechanisms whereby D. frontalis initially locates hosts have not been demonstrated, whereas D. terebrans responds strongly to host odors. Because D. terebrans produces frontalin, the primary aggregation pheromone component for D. frontalis, and commonly arrives on hosts prior to D. frontalis , it has been hypothesized that D. terebrans pheromone components can mediate D. frontalis location of suitable, living trees. We assessed this possibility with studies of the semiochemical interactions between D. frontalis and D. terebrans. Coupled gas chromatography-electroantennographic detection analyses indicated that D. terebrans produces nine different olfactory stimulants for D. frontalis, nearly all of them known semiochemicals for D. frontalis. A trapping experiment designed to address the potentially confounding influence of lure contamination confirmed that the D. terebrans pheromone component exo -brevicomin enhances attraction of D. frontalis and thus could be an attractive kairomone. In ambulatory bioassays, male D. frontalis were strongly attracted to odors of frass of solitary female and paired D. terebrans , indicating their attraction to the naturally occurring semiochemicals of D. terebrans. Cues from D. terebrans may influence host and mate-finding success of D. frontalis and, thereby, the latter's virulence. [ABSTRACT FROM AUTHOR]

The scarab genus Osmoderma (Coleoptera: Scarabaeidae) includes several large species called hermit beetles that develop within dead and decaying hardwood trees. Males of at least three Palearctic species produce the aggregation-sex pheromone (R)-(+)-γ-decalactone, including the endangered O. eremita (Scopoli). However, hermit beetles have received less attention in the western hemisphere, resulting in a large gap in our knowledge of the chemical ecology of Nearctic species. Here, we identify (R)-(+)-γ-decalactone as the primary component of the aggregation-sex pheromone of the North American species Osmoderma eremicola (Knoch). Field trials at sites in Wisconsin and Illinois revealed that both sexes were attracted to lures containing (R)-(+)-γ-decalactone or the racemate, but only males of O. eremicola produced the pheromone in laboratory bioassays, alongside an occasional trace of the chain-length analog γ-dodecalactone. Females of the congener O. scabra (Palisot de Beauvois) were also significantly attracted by γ-decalactone, suggesting further conservation of the pheromone, as were females of the click beetle Elater abruptus Say (Coleoptera: Elateridae), suggesting that this compound may have widespread kairomonal activity. Further research is needed to explore the behavioral roles of both lactones in mediating behavioral and ecological interactions among these beetle species. [ABSTRACT FROM AUTHOR]

Drosophila suzukii (Matsumura) is an exotic pest of economic importance that affects several soft-skinned fruits in Mexico. Previously, we found that yellow or yellow-green rectangular cards inside a transparent trap baited with attractants improved D. suzukii capture. In this study, we evaluated the influence of rectangular cards with different yellow shades inside a transparent multi-hole trap baited with apple cider vinegar (ACV) on D. suzukii capture in the field. Second, we tested whether ACV-baited traps with cards of other geometric shapes affected D. suzukii catches compared to traps with rectangular cards. Third, we evaluated the effects of commercial lures combined with a more efficient visual stimulus from previous experiments on trapping D. suzukii flies. We found that ACV-baited traps plus a yellow-shaded rectangle card with 67% reflectance at a 549.74 nm dominant wavelength captured more flies than ACV-baited traps with yellow rectangle cards with a higher reflectance. Overall, ACV-baited traps with rectangles and squares caught more flies than did ACV-baited traps without visual stimuli. The traps baited with SuzukiiLURE-Max, ACV and Z-Kinol plus yellow rectangles caught 57, 70 and 101% more flies, respectively, than the traps baited with the lure but without a visual stimulus. [ABSTRACT FROM AUTHOR]

The shy-bold behavioral continuum is an element of animal behavior which is often studied for its ecological relevance, particularly in the context of predation risk. How individuals respond to various predation cues is well studied at the individual level, but relatively little is known about how these responses can differ among closely related species. We exposed individual wild-caught juvenile bluegill (Lepomis macrochirus) and pumpkinseed (L. gibbosus) to kairomones of a common predator (Northern pike, Esox lucius), conspecific alarm cues, or a lake water control in a Z-maze trial commonly used to assess relative levels of bold and exploratory behaviors. Neither species exhibited any significant behavioral responses to either predation cue, but bluegill consistently displayed more bold-type behaviors than pumpkinseed. Although the lack of a behavioral response to predation cues in this study is equivocal, we identify clear differences in boldness between these two congeners and discuss the possibility of ecological niche differentiation driving these behavioral differences. Significance Statement: Closely related species exposed to similar predator guilds may differ in their behavioral responses to predation risk, particularly during different life-history stages. We exposed juveniles of two co-occurring sunfish congeners (Lepomis spp.) to chemical predation cues (predator kairomones or conspecific alarm cues) in a Z-maze assay to assess relative levels of bold and exploratory behaviors. Bluegill (L. macrochirus) were consistently bolder and more proactive than pumpkinseed (L. gibbosus). Ontogenetic ecological niche differentiation between these species may be the cause of these observed differences and life-history trajectories should be considered in the design of future research questions. [ABSTRACT FROM AUTHOR]

The 19 species of Dendroctonus bark beetles native to North America include several of the most significant biotic mortality agents of conifers in this region, and they have impacted millions of hectares of forest in recent decades. Semiochemical attractants play several vital roles in the biology of these insects including host finding, host assessment, and mate finding. They are key to the virulence of these insects, since they mediate the mass attacks that enable killing and reproduction within healthy trees. These attractants consist of combinations of thirteen identified pheromone components in three primary chemical classes and at least ten host-associated compounds dominated by monoterpene hydrocarbons in host defensive resin. Due to their potential for use in pest management technologies, semiochemical attractants for Dendroctonus have received extensive research into their chemical compositions and effects on insect behavior. This paper is intended as a synthesis of this research over the past 60 years as well as a critical examination of approaches to investigation of this topic and interpretation of experimental results. Its purpose is to assist practitioners in formulating suitable attractive lures for use in applications and identify gaps in knowledge of the semiochemistry of Dendroctonus that should be addressed if the practical potential of attractants is to be fully realized. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Sea urchins can strongly reduce their mobility, exposure to predation, and feeding rates upon detection of chemical cues produced by predators, driving behavioral effects on grazing activity that may contribute to macroalgal community dynamics. However, the extent of chemically induced antipredator behaviors in urchins can vary by predator–prey species pair and ecological context and is therefore important to characterize in novel settings. Additionally, the effect of predator and prey size on urchin reactions to predator cues has rarely been considered, with the few existing examples yielding mixed conclusions. Here, we used a replicated split‐plot experiment to measure the effects of red rock lobsters (Jasus edwardsii) on consumption of macroalgae by the New Zealand sea urchin (Evechinus chloroticus) across a range of predator and prey body sizes. Overall, per‐capita consumption rates of kelp by urchins declined by 30% in the presence of lobsters, though feeding activity varied widely among individuals. Based on mass‐specific measurements of feeding rates, responses to predator cues appeared similar across all urchin sizes but only yielded distinguishable differences in the amount of kelp consumed in trials with larger urchins due to their considerably higher feeding capacity. Conversely, consumption rates of kelp by urchins had no apparent relationship with lobster size, likely due to chemical cue saturation in our experimental setting or a risk gradient that was insufficient to elicit a graded behavioral response. Our findings provide new evidence for a nonconsumptive effect of lobsters on feeding rates of an important grazer that can potentially reinforce the ecological role of this key predator in New Zealand kelp beds.

Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) is an important parasitoid of lepidopteran pests. Its parasitism success is related to its foraging behavior, mediated by kairomones from its hosts. We aimed to evaluate the chemotactic responses and parasitism of T. pretiosum from Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs as well as the parasitoid maintained for three generations in Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) eggs. Chemotactic responses of T. pretiosum from both hosts were evaluated in a dual choice olfactometer. Females were submitted to a choice between washed vs. unwashed eggs of E. kuehniella or S. frugiperda, as well as to unwashed eggs of both hosts. Egg extracts of both hosts were also contrasted with hexane and with each other. Parasitism of T. pretiosum exposed to eggs of the two species was also evaluated. Females from E. kuehniella were more attracted to odors from eggs of this host whenever it was present. Third generation parasitoids from S. frugiperda eggs were more attracted to eggs and egg extract of S. frugiperda than to those from E. kuehniella. The highest number of parasitized eggs and emerged parasitoids in S. frugiperda was observed in parasitoids coming from the third generation in this host. Therefore, imaginal conditioning could be an alternative to be considered for T. pretiosum learning before releasing, possibly optimizing its search and parasitism process in S. frugiperda eggs. [ABSTRACT FROM AUTHOR]

Effective early detection, monitoring and management methods are critical for reducing the impacts of insect pests in agriculture and forestry. Combining host plant volatiles with sex pheromones could enhance trapping methodologies, whilst the use of non-host volatiles could improve the effectiveness of pest management through repellency effects. In this meta-analysis approach, we analysed 51 studies that used electroantennograms (EAG), wind tunnels and/or field traps to evaluate the antennal and behavioural responses of Lepidoptera to sex pheromones combined with attractant or repellent plant volatiles. Proposed attractant plant volatiles had a positive association with female Lepidoptera responses to sex pheromone, but effects on males were highly variable, with unexpected repellency reported in some studies. Proposed repellent plant volatiles were significantly or near-significantly negatively associated with male attraction to sex pheromones but were scarcely studied. Sub-group analysis identified that male responses to sex pheromone were reduced when the dose of attractant plant volatile relative to sex pheromone was increased. Green-leaf volatiles were associated with the strongest positive effects for males in field traps. Multiple-compound attractant plant volatile blends were less effective than single compounds in field studies. Our analysis demonstrates, (i) the potential value of combining host plant volatiles with sex pheromones to capture females rather than only males, (ii) the importance of identifying appropriate host plant volatiles and optimal relative doses, and (iii) the potential for non-host plant volatile use in pest management strategies. [ABSTRACT FROM AUTHOR]

In 2006, we evaluated the effects of combining lures releasing pine host kairomones (ethanol + α-pinene) with lures releasing bark beetle pheromones (ipsenol + ipsdienol) on trap catches of predators associated with bark and woodboring beetles in Florida, Georgia, Louisiana, and Virginia. Catches in traps baited with all 4 compounds were greater than those in traps baited with either binary blend for the common predators Thanasimus dubius (F.) (Coleoptera: Cleridae), Temnoscheila virescens (F.) (Coleoptera: Trogossitidae), Aulonium tuberculatum LeConte (Coleoptera: Zopheridae), and Lasconotus spp. (Coleoptera: Zopheridae). The same was true for: Enoclerus nigripes (Say) (Coleoptera: Cleridae) at 2 of 3 locations; Platysoma cylindricum (Paykull) (Coleoptera: Histeridae) at 3 of 4 locations; and Corticeus spp. (Coleoptera: Tenebrionidae) at 2 of 6 locations. In contrast, the addition of ethanol + α-pinene to traps baited with ipsenol + ipsdienol reduced catches of Platysoma attenuatum LeConte (Coleoptera: Histeridae) at 2 of 4 locations. [ABSTRACT FROM AUTHOR]

The cypress bark beetle, Phloeosinus aubei (Coleoptera, Curculionidae, Scolytinae) prefers to build breeding galleries in decaying host trees. However, volatile cues specific to decaying or actively infested trees have not yet been reported. Any such information would be useful for the management of this invasive, wood-boring species that has become established across Europe in the temperate zone and is now a key pest of ornamental Cupressaceae in nurseries and urban landscapes. Our objective was to reveal key components in host volatiles specific to stressed trees, which could be potential signals for the pest of its suitability for colonisation. Volatile profiles of arborvitae, Thuja occidentalis 'Smaragd' suffering from either dehydration or fresh infestation of P. aubei was collected and compared to that samples from healthy control trees. Analyses of volatiles by gas chromatography coupled to an electroantennographic detector revealed substantial differences between healthy, dehydrated and infested trees. Structural elucidation of the major antennally active components revealed that both α-pinene and α-thujene were prevalent in the volatiles of infested trees, whilst α-thujone was the major component in volatiles of healthy trees. In volatiles collected from trunks housing fresh P. aubei female nuptial chambers, sharp increases of β-pinene, myrcene, limonene, and p-cymene were noticed, alongside trace amounts of camphene and fenchene. Volatiles collected from fresh frass showed a similar profile, but with a somewhat smaller amount of limonene. Fenchone was present in each type of volatiles, however, only in low amounts. Further studies should be directed to reveal the behavioural role of these components, which could be helpful in developing kairomone-based techniques for monitoring the flight of the pest in stands of scale-leafed trees. [ABSTRACT FROM AUTHOR]

Predatory long-legged flies of the genus Medetera are important, but currently understudied, natural enemies of Scolytinae bark beetles such as Ips typographus. Medetera flies lay eggs on beetle-infested trees, where the developing larvae find their prey, but the chemical cues used by Medetera to locate infested trees are currently unknown. To identify odors attracting Medetera signaticornis, a species in Europe, headspace samples were collected at several time-points through different stages of I. typographus attacks on logs of Norway spruce (Picea abies). The headspace samples were analyzed using combined gas chromatography and mass spectrometry (GC–MS), and gas chromatography coupled with electroantennographic detection (GC-EAD) to determine compounds that stimulate M. signaticornis antennae. Antennae of M. signaticornis males and females were found to detect (–)-cis-verbenol, (+)-trans-verbenol and myrtenol, which are known to be produced by bark beetles. Antennal responses were also observed for verbenene, isoterpinolene, α-pinene oxide, camphor, pinocamphone, terpinene-4-ol, myrtenal, borneol, α-terpineol, geranyl acetone, and verbenone, which are primarily produced by microorganisms, and α-pinene, α-fenchene, β-pinene, camphene, 3-carene, limonene, γ-terpinene, and terpinolene, known spruce tree compounds. In field experiments testing two synthetic blends containing 18 antennal active and two additional compounds 2-methyl-3-buten-2-ol and ipsdienol we observed significant attraction of M. signaticornis within 24 h. These attractive blends can form the basis for development of Medetera monitoring lures for use in future forest and pest management. [ABSTRACT FROM AUTHOR]

Field testing of Biologically Active Substances on the behavior of the entomophagous Trichogramma evanescens Westw. was conducted in two variants: In the first variant, where T. evanescens was released in the center of the plot, four plants were treated with a 30% concentration of kairomones extract of the cereal moth (optimal variant) for 5 minutes in the corners of the plot, and the percentage of cereal moth eggs parasitized varied from 18.43 to 31.0. In the second variant, where T. evanescens was released in the corners of the plot, four plants were treated with the kairomones extract of the cereal moth in the middle of the plot, and the percentage of cereal moth eggs parasitized varied from 11.65 to 27.50. In the control plot, plants were not treated with kairomones, but T. evanescens was released in the center of the plot (C1), where cards with moth eggs were fixed. The percentage of cereal moth eggs parasitized varied from 6.10 to 14.50 in the corners of the plot (C2), and the percentage of cereal moth eggs parasitized varied from 7.10 to 11.10. ACKNOWLEDGEMENTS Research was carried out within the project of the State Program 20.80009.5107.27 "Elaboration of the alternative methods based on environmentally friendly means and procedures for harmful arthropods control in different agricultural crops", financed by the National Agency for Research and Development. [ABSTRACT FROM AUTHOR]

Larvae of some leaf beetles carry masses of feces covering parts or all of the body, which is called a "fecal shield". In general, the shield is thought to be a defense structure against natural enemies. However, some studies have suggested that defense effectiveness varies depending on the natural enemy. In this study, we used a fecal retention leaf beetle Ophrida xanthospilota (Coleoptera: Chrysomelidae), and 2 local generalist predators (an ant, Camponotus japonicus (Hymenoptera: Formicidae) and a stinkbug, Arma custos [Hemiptera: Pentatomidae]) as a system to test the hypothesis that the fecal shield of O. xanthospilota plays different roles in predation behavior of different predators and can provide multiple chemical communication signals in predator–prey interactions. Prey bioassays showed that the fecal shield of O. xanthospilota larvae repelled the ant C. japonicus while attracting the stinkbug A. custos. The results also strongly demonstrated that hexane extracts of the fecal shield significantly repelled C. japonicus, while dichloromethane (DCM) extracts did not inhibit ant predation. Interestingly, DCM extracts attracted A. custos, but hexane extracts did not. Therefore, we suggest that the fecal shield is a double-edged sword for the larvae of O. xanthospilota. Our results also indicated that the risk–benefit tradeoff of an insect should be estimated at a community level involving multiple enemies (predators and parasites) and herbivores, rather than in a single prey–predator pair. [ABSTRACT FROM AUTHOR]

The homoterpenes 4,8‐dimethyl‐1,3,7‐nonatriene (DMNT) and 4,8,12‐trimethyl‐1,3,7,11‐tridecatetraene (TMTT) are volatile products of plant metabolism reported from diverse plant taxa and multiple plant tissues. As such, they have a range of potential ecological functions. Here, we review the key literature to assess evidence for roles in contrasting plant–arthropod interactions. TMTT, and DMNT especially, have been reported as sometimes dominant constituents of floral scents from angiosperm taxa ranging from primitive Magnoliales to more advanced, taxonomic orders of economic significance such as Fabales and Sapindales. Although all taxa producing TMTT and DMNT in floral scents are entomophilous ('insect pollinated'), experimental evidence for an assumed role of these homoterpenes in pollinator attraction is limited. Representing a trade‐off, in some cases, homoterpenes in floral scents have been shown to act as kairomones, attracting herbivores. Additionally, both TMTT and DMNT are released by plant foliage in response to arthropod feeding, mechanical damage simulating feeding, or even egg deposition. Evidence for a functional role in herbivore‐induced plant volatile (HIPV) blends comes from a wide range of angiosperm orders, including anemophilous ('wind pollinated') taxa, as well as from gymnosperms. We conclude by considering how TMTT and DMNT function in community‐level interactions and highlighting research priorities that will reveal how plants avoid trade‐offs from contrasting ecological functions of DMNT and TMTT release and how homoterpene production might be exploited to develop improved crop varieties. [ABSTRACT FROM AUTHOR]

Many blood-feeding arthropods use volatile organic compounds (VOCs) to detect their vertebrate hosts. The role of chemical interactions in mediating the behavior of hematophagous insects and ticks has been investigated before but remains poorly understood in hematophagous mesostigmatic mites. The poultry red mite Dermanyssus gallinae is an obligatory blood-sucking mesostigmatic mite that feeds on birds and causes damage in poultry farms. We characterized the attractive response of D. gallinae to candidate VOCs previously reported from the odor emitted by living hens. We performed in-vitro choice-test bioassays as well as semi-field and field trials using baited and unbaited traps, in the presence and absence of hens. Among different tested combinations of VOCs, a blend of 5 VOCs (mix1.0) was significantly attractive to our reference population of D. gallinae in vitro, whereas the same individual compounds tested alone were not attractive. Ammonia was attractive on its own and increased the mix1.0 attractiveness. The attractiveness of mix1.0 was confirmed at 'natural' spatial scales in the absence of hens both at the lab and on the farm that provided the reference population. The presence of hens inhibited the mix1.0 attractiveness. The attractive power of mix1.0 was not found in other farms. This research is an important step to advance our understanding of host-parasite interactions in hematophagous mesostigmatic mites and paves the way for developing alternative control tools against D. gallinae by interfering with chemical interactions. Moreover, it underlines the importance of assessing kairomonal activity on different pest populations when developing attract-and-kill systems. [ABSTRACT FROM AUTHOR]

Simple Summary: The brown marmorated stink bug, Halyomorpha halys, is an invasive pest of agricultural crops, ornamentals, and human structures. In its native range, populations are suppressed primarily by parasitoid wasps that attack the egg stage. A promising adventive parasitoid, the samurai wasp, Trissolcus japonicus, has become established in the U.S., including Utah. According to ecological models, Utah is marginally suitable for the samurai wasp and poses unique challenges to its establishment from extreme climates and high elevation. Biological control enhancement efforts, such as deploying stink bug kairomones to attract parasitoids, may lead to the enhanced suppression of the brown marmorated stink bug. To evaluate the efficacy of this approach, experimental lures loaded with varying blends and release rates of stink bug kairomones were tested in field and mesocosm trials. This study found low parasitism in the field, while mesocosm trials demonstrated the efficacy of a single- and dual-compound blend at the 10 mg load rate for the attraction of the samurai wasp. These results support the validity of using rubber septa as a release device for kairomones of stink bugs and provide a baseline for future work on attracting samurai wasps with lures in a field environment. In its native range, Halyomorpha halys (Stål) is suppressed by parasitoids in the genus Trissolcus (Hymenoptera: Scelionidae). Trissolcus native to Utah have demonstrated low parasitism of H. halys, while adventive Trissolcus japonicus (Ashmead) have shown parasitism of up to 20%. Custom rubber septa lures containing stink bug kairomones, n-tridecane (attractant), and (E)-2-decenal (repellent), at 100%, 90%, and 80% levels of attractant (10 mg load rate), were placed adjacent to sentinel H. halys egg masses in northern Utah field trials. Egg masses were evaluated for the presence and intensity (proportion of parasitized eggs) of parasitism. Parasitism by T. japonicus and T. euschisti (Ashmead) was low; however, the 100% lure showed double the parasitism of the control and more than three times that of the 90% and 80%. Two-way choice mesocosm trials in the laboratory evaluated previous lures and a lower load rate of 5 mg—100% attractant treatment. Lures of 10 mg at 100% and 80% were more attractive to T. japonicus than the control, while 5 mg at 100% and 10 mg at 90% showed no significant attraction. Our results support a proof-of-concept of rubber septa as release devices for kairomones to attract T. japonicus and provide a baseline for future field-based studies. [ABSTRACT FROM AUTHOR]

In 2011–2013, we determined the interactive effects of the cerambycid pheromones racemic syn -2,3-hexanediol, racemic 3-hydroxyhexan-2-one, and racemic 3-hydroxyoctan-2-one on trap catches of predators associated with bark and woodboring beetles in north Georgia and South Carolina. Temnoscheila virescens (F.) (Coleoptera: Trogossitidae) was attracted to traps baited with 3-hydroxyhexan-2-one; ethanol enhanced attraction. Traps baited with syn -2,3-hexanediol attracted Chariessa pilosa (Forster) (Coleoptera: Cleridae); attraction was interrupted by 3-hydroxyhexan-2-one. An assassin bug Apiomerus crassipes (F.) (Hemiptera: Reduviidae) was attracted to traps baited with 3-hydroxyhexan-2-one and/or 3-hydroxyoctan-2-one. Ethanol had no effect on trap catches of C. pilosa and A. crassipes. We compared response profiles of these predators to those of longhorn beetles captured in these same studies to provide insights on possible ecological interactions between these species. [ABSTRACT FROM AUTHOR]

Spotted cucumber beetle (Diabrotica undecimpunctata howardi; also known as southern corn rootworm) is a pest feeding on many crops, including cucurbits, corn (maize), peanuts, beans, and other crops and wild plants in North America. On cucurbit crops, where it co-occurs with striped cucumber beetle (Acalymma vittatum), both are key pests that vector Erwinia tracheiphila, a destructive pathogen that causes bacterial wilt. Here we deployed synthetic vittatalactone, the male-produced aggregation pheromone of A. vittatum, as lures in the field, to measure attraction of the target and non-target insects. Both sexes of D. u. howardi were strongly attracted to the vittatalactone lures (5–7.5-fold compared to blank trap) throughout the growing season in Maryland and Virginia, USA. Moreover, D. u. howardi was more attracted to live A. vittatum males feeding on squash plants than to plants with females or without any beetles, confirming the genuine organismal cross-attraction between these two key pests. The kairomonal attraction to vittatalactone suggests that it functions as a "keystone semiochemical," mediating the colonization of cucurbits by multiple herbivore species. Such cross attraction could allow for use of vittatalactone in management of multiple pest species, with potential reduction of pesticide use in cucurbit crops. [ABSTRACT FROM AUTHOR]

Planktonic bacteria are an important part of aquatic ecosystems and interact with zooplankton. However, it is still unclear whether different planktonic bacteria differentially interfere with the responses of zooplankton to their predators. Here, we investigated the effects of different planktonic bacteria, which were isolated and purified from natural lakes, on the anti-predation (Rhodeus ocellatus as the predator) defense responses of Daphnia magna. Our results showed that the effects of planktonic bacteria on the induced life-history defenses of Daphnia were speciesspecific. Bacteria which increased (e.g., Escherichia coli, Citrobacter braakii) Daphnia body size also promoted the induced defense of body size, whereas bacteria which decreased (e.g., Pseudomonas spp.) Daphnia body size also inhibited the induced defense of body size. In addition, the same bacteria had different effects on induced defense traits. Some bacteria (e.g., E. coli) promoted the induced defense of body size but reduced the induced defense of offspring number, whereas other bacteria (e.g., Aeromonas hydrophila, Aeromonas veronas) weakened the induced defense of body size but had no significant effect on the induced defense of offspring number. Moreover, the differential effects of planktonic bacteria on Daphnia's induced defenses were not related to the bacterial degradation of kairomone. This study illustrated, for the first time, the species-specific effects of planktonic bacteria on predator- induced responses of Daphnia. [ABSTRACT FROM AUTHOR]

Varroa mite, Varroa destructor is the most important ectoparasite of the honey bee, Apis mellifera worldwide, contributing to colony collapse. The development of alternative non-toxic methods against this pest is needed, as most of the wide-used acaricides in apiculture are banned in the European Union, which increase the risk of developing resistant mite populations against the remaining few products. In order to reveal biological basis of a new, semiochemical-based method, the aim of this study was to search for olfactory stimuli, used by female Varroa mites in orienting to drone brood for egglaying. Volatiles of uncapped drone brood were collected in situ, inside bee-hives, using either charcoal, or HayeSep® Q filters. Collections were analyzed by gas chromatograph linked to an electrotarsogram detector (GC-ETD), using the foreleg of female mite. Results showed that most components were present in collections trapped by any of these filters. However, some components appreared only in charcoal-, while others only in HayeSep® collections, respectively. Out of the large number of components, a few elicited electrophysiological responses. Structure elucidation of these active components are underways. Futher behavioral studies should reveal, which components play role in attraction of Varroa mites. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hydrobiology / Shuisheng Shengwu Xuebao is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Some coniferophagous bark and woodboring beetles overlap spatially and temporally in host trees. These larval interactions have been classified as competitive and predatory in favor of the larger and more mobile woodborer larvae. In some bark beetles, larval traits have been reported that facilitate evasion of woodborer larvae. Both bark beetles and woodborers mediate mating on host material with volatile pheromones. Although it is known that some woodborers eavesdrop on bark beetle aggregation pheromones to facilitate host location, it is not known what effect woodborer pheromones have on bark beetles. The pheromone monochamol is used by most Monochamus spp. Dejean and coniferophagous species from this genus co-occur with bark beetles in host tissues. Because of the negative consequences these larval interactions have for bark beetles, we hypothesized that the woodborer pheromone monochamol would inhibit captures of sympatric and synchronic bark beetles to intercept traps baited with their aggregation pheromones and host volatiles. We tested this hypothesis in 2 systems, 1 in Ontario, Canada, and another in Setúbal, Portugal with field trapping experiments. Trap captures of Ips sexdentatus (Boerner) (Coleoptera: Scolytinae), Orthotomicus erosus (Wollaston) (Coleoptera: Scolytinae) (2 bark beetle species captured in Portugal), and Ips pini (Say) (Coleoptera: Scolytinae) (1 bark beetle species captured in Canada) were reduced by the presence of monochamol. These results suggest that an additional evasion mechanism in some bark beetles is the detection of the woodborer pheromone monochamol and subsequent reduced response to aggregation pheromone and host volatiles in the presence of this woodborer pheromone., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

A preliminary chemical analysis of the OLFE extract did not detect any of the four known pheromone components or precursors, but further study is needed to understand the interaction between the pheromone and the kairomone attractants. In several species, host volatiles mediate male attraction to mating sites in advance of female emissions of sex pheromones or can synergistically increase the attraction of males when they co-occur with the pheromones [[38], [40], [42]]. When tests 1 and 2 were pulled together, no significant differences were noticeable between the concentrated kairomone and the pheromone lures, while the kairomone lure attracted more than the unbaited traps (H SB 3,60 sb = 24.748; I p i = 0.000) (Figure 3). Keywords: cocoa pod borer; Conopomorpha cramerella; kairomone; pheromone; lure development; monitoring tool EN cocoa pod borer Conopomorpha cramerella kairomone pheromone lure development monitoring tool N.PAG N.PAG 11 09/27/22 20220901 NES 220901 1. [Extracted from the article]

The black turpentine beetle, Dendroctonus terebrans, is an economically important pest of pines in the Southeastern U.S., with a high potential for invasion to other pine-rich regions. Dendroctonus terebrans attraction to an injured host tree lessens over time as the host material degrades. Likewise, kairomonal volatiles emitted from the host change as constituents of the defensive resin oxidize. Therefore we hypothesized that volatiles associated with a fresh host would be more attractive to D. terebrans than those associated with a dead or dying host. We replicated the natural oxidation process of turpentine, fractionated the distilled products to isolate the oxidized products, and deployed the complex mixtures to measure field attraction based on the amount of oxidation performed. Contrasting with previous studies, our results suggest that D. terebrans attraction is not primarily based on host tree degradation. In a second experiment incorporating Dendroctonus pheromones, we demonstrate D. terebrans has a displacement-dependent response to endo-brevicomin, a pheromone associated with the sympatric southern pine beetle, D. frontalis. This has implications not only for possible interspecific signaling, but also for the role of endo-brevicomin in D. terebrans colonization behavior. The results from this study broaden the understanding of D. terebrans chemical ecology and directly contribute to the development of an effective lure-based monitoring system that will benefit future research and management efforts. This may become important if the species is established outside its native range, as in the closely related red turpentine beetle, Dendroctonus valens, which caused mass pine tree mortality following its introduction to Asia. [ABSTRACT FROM AUTHOR]

Mosquitoes use chemical codes to locate and discriminate among vertebrate hosts to obtain a blood meal. Recent advances have allowed for the identification of the chemical codes used by mosquitoes to locate and discriminate humans from other vertebrate hosts. Humans are incidental “dead-end” hosts for the West Nile virus, which is maintained in an enzootic cycle, primarily through its transmission between infected birds by Culex mosquitoes. Host-seeking Culex mosquitoes are attracted to the odor of chicken, which are used in sentinel traps to monitor West Nile virus transmission. Using combined gas chromatography and electroantennography and mass spectrometry we identify a blend of volatile organic compounds present in chicken emanates, including mostly salient bioactive compounds previously identified in human emanates. When released at their identified ratios, this blend elicits behavioral responses of Culex pipiens molestus and Culex quinquefasciatus similar to that to the natural chicken odor. Tested under field conditions, this blend attract Culex spp. and other species of mosquitoes using birds among their hosts. This study provides evidence for conserved chemical codes for resource location by mosquitoes, and highlights the intricate role of CO2 for host-seeking mosquitoes. The identification of conserved chemical codes, which drive innate preference behaviors that are fundamental for survival and reproduction, provides important substrates for future control interventions targeting disease vector mosquitoes.

Daphnia can develop a VARIETY of inducible defensive traits when they sense predator kairomone and transmit the predation risk information from females to their offspring. However, limited research has focused on how Daphnia females transmit predation risk information across multiple broods when the mothers and offspring are respectively exposed or not exposed to predation pressure.Here we conducted a prolonged predation risk transmission experiment, where three generations of Daphnia pulex individuals were cultured with or without fish kairomone until they produce six broods of offspring. Life history traits and morphological defensive traits were measured to investigate how inducible defensive traits were transmitted across generations and multiple broods.Our results demonstrated that (1) inducible defensive traits of offspring were mainly determined by the offspring's environment rather than their mothers' experience; and (2) as the mothers produced more broods of offspring, inducible defensive traits of the offspring were gradually increased and then decreased.The present study highlights the reversibility and differences among generations and broods of the transmission of predation risk information via transgenerational effects, which provides a basis for further understanding of transgenerational plasticity across broods. [ABSTRACT FROM AUTHOR]

BACKGROUND: The European tarnished plant bug Lygus rugulipennis Poppius (Hemiptera: Miridae) can cause several types of damage to crops grown in greenhouses and fields, including flower abortion in eggplant, stem and fruit damage in cucumbers, and splits in chrysanthemums. Studies suggest that both male and female L. rugulipennis may be more attracted to traps based on visual attraction than pheromone‐based trap. Therefore, the aim of this study was to evaluate the effectiveness of a water trap with LED lights and semiochemicals in trapping L. rugulipennis in the laboratory and greenhouse. RESULTS: The results showed that water traps equipped with white LED light caught 20– 30 times more bugs than did the sex pheromone‐based traps in greenhouse experiment. During the week of peak flight, the LED water trap caught a total of 29 males and females, whereas the sex pheromone caught only one male. Among the semiochemicals tested in a Y‐tube, both males and females were attracted to ß‐caryophyllene, but not in the presence of the sex pheromone, whereas both males and females were attracted to pentyl butyrate in the presence of the sex pheromone. The pheromone plus bean plant odor was attractive to the insects, suggesting an interaction between plant odor and pheromone. CONCLUSION: Overall, the findings of the study showed that the water trap with LED light could be an effective method for trapping L. rugulipennis in greenhouses. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Trichogramma pretiosum Riley (Hymenoptera Trichogrammatidae) is known to use a wide range of chemical cues to locate its hosts. Its presence in areas where mating disruption control has been used for Grapholita molesta (Busck) (Lepidoptera Tortricidae) has led to questions about the effect of these semiochemicals on the behaviour of this parasitoid. Therefore, we evaluated the chemotactic responses and parasitism of T. pretiosum at different ages to G. molesta sex pheromone, as well as the ability of this parasitoid to learn and to recognize G. molesta eggs volatiles. Chemotaxis of 24, 48, 72, and 96 h-old T. pretiosum mated males and females was recorded using an olfactometer, contrasting the synthetic sex pheromone blend (Z-8-dodecenyl acetate, E-8-dodecenyl acetate, and Z-8-dodecenol - 10 µl at 0.001%) versus hexane. We also observed the response of parasitoids (females with and without experience on the host eggs) to G. molesta rinsed and unrinsed eggs (olfactometry and parasitism). Our results evidenced that T. pretiosum females are able to recognize G. molesta sex pheromone and also that learning process on G. molesta eggs increases their chemotactic response and parasitism in unrinsed eggs. Understanding the interactions between T. pretiosum and G. molesta is the first step to design a rational combination among different sustainable pest control techniques. [ABSTRACT FROM AUTHOR]

The red palm weevil (Rhynchophorus ferrugineus L) is an important pest for date palm plantation in all over the world. The present study deals with the optimization of different parameters for trapping of red palm weevil by utilizing pheromone traps. Different field trials have been performed at district Khairpur Mir's, Sindh-Pakistan. Therefore, different field trials have been performed at date palm orchards of district Khairpur Mir's, Sindh-Pakistan. During the field trials, various parameters such as aggregation pheromone (ferrugineol; 4-methyl-5-nonanol+ 4-methyl-5-nonanone), kairomone (Ethyl acetate, EA) dosages, effect of date fodder, trap density, the effect of trap color and seasonal changes have been optimized. From the results, it has been revealed that the traps baited with 300 g of date fodder, captured more adult red palm weevil as compared to the traps without date fodder. In addition, 3 mg/trap/day pheromone dose and 5 mg/trap/day EA captured the maximum number of adult red palm weevils and effective trap density was found to be 11 traps/ha, while further higher trap density has no significant difference. Moreover, the darker color traps catch a significant higher number of weevils as compared to white or light-colored bucket traps. [ABSTRACT FROM AUTHOR]

Abstract The parasitic mite Varroa destructor devastates honey bee (Apis mellifera) colonies around the world. Entering a brood cell shortly before capping, the Varroa mother feeds on the honey bee larvae. The hormones 20‐hydroxyecdysone (20E) and juvenile hormone (JH), acquired from the host, have been considered to play a key role in initiating Varroa's reproductive cycle. This study focuses on differential expression of the genes involved in the biosynthesis of JH and ecdysone at six time points during the first 30 hr after cell capping in both drone and worker larvae of A. mellifera. This time frame, covering the conclusion of the honey bee brood cell invasion and the start of Varroa's ovogenesis, is critical to the successful initiation of a reproductive cycle. Our findings support a later activation of the ecdysteroid cascade in honey bee drones compared to worker larvae, which could account for the increased egg production of Varroa in A. mellifera drone cells. The JH pathway was generally downregulated confirming its activity is antagonistic to the ecdysteroid pathway during the larva development. Nevertheless, the genes involved in JH synthesis revealed an increased expression in drones. The upregulation of jhamt gene involved in methyl farnesoate (MF) synthesis came into attention since the MF is not only a precursor of JH but it is also an insect pheromone in its own right as well as JH‐like hormone in Acari. This could indicate a possible kairomone effect of MF for attracting the mites into the drone brood cells, along with its potential involvement in ovogenesis after the cell capping, stimulating Varroa's initiation of egg laying.

Spiroacetals such as E-7-methyl-1,6-dioxaspiro[4,5]decane (trans-conophthorin; tC) and acetamides [predominantly N-(3-methylbutyl)acetamide; N3MBA], are two major groups of volatiles discovered in venoms of many Vespidae. In the course of testing the attractiveness of tC and N3MBA to Vespidae using Rescue® Wasp TrapStiks, a significant number of female milichiids, Desmometopa nearctica Sabrosky and D. sordida (Fallén) (Diptera: Milichiidae) were trapped as well. However, the attraction of vespid wasps was not significant at the dosages tested. We found a significant synergistic effect of tC and N3MBA in attracting Desmometopa flies. Both D. nearctica and D. sordida are kleptoparasitic species; and we conclude that females of these two milichiid flies use tC and N3MBA (and likely other volatiles) released from venom glands of the social vespids (yellowjackets, paper wasps and hornets) as kairomones to locate disturbed, injured, or freshly killed insects (vespids and/or their prey) as a protein-rich food source for egg development and production. [ABSTRACT FROM AUTHOR]

One of the major research goals in ecology is to understand predator–prey interactions. However, our understanding of how prey express phenotypic plasticity in response to co‐occurring multiple predators is limited in many systems.Here, we use the rotifer Brachionus calyciflorus as model organism to test how prey responds to co‐occurring predators through a series of related experiments. Firstly, we examined the effects of the density of a fish predator Carassius auratus on morphological traits in B. calyciflorus. Secondly, we examined the effects of larval C. auratus and Asplanchna brightwellii (a rotifer predator) on morphological defensive traits (body length, body width, anterior spine length, and posterolateral spine length) of B. calyciflorus.We show that B. calyciflorus develops smaller body size and shorter spine length when exposed to media conditioned using larval fish, and that high larval fish densities induce more pronounced responses than low densities. We also show that B. calyciflorus is able to discriminate between the two predators by producing opposing morphological adaptations (i.e., larger body size and longer posterolateral spines against A. brightwellii, but smaller body size and shorter spine length when exposed to the visual predator [larval fish]). However, B. calyciflorus develops intermediate, trade‐off responses in all morphological traits when exposed to conflicting threats from a combination of predators with different size and feeding strategies.These results show how prey are not necessarily passive victims, but rather, use countermeasures against predation – they actively develop responses to counteract their vulnerability to different predators by rapidly adjusting their morphology and life‐history traits to the existing predator regimes. [ABSTRACT FROM AUTHOR]

Semiochemicals such as herbivore-induced plant volatiles (HIPVs) and host chemicals serve as communication signals for parasitoids searching for oviposition sites. The braconid koinobiont endoparasitoid Dolichogenidea gelechiidivoris (Hymenoptera: Braconidae) efficiently parasitises larvae of Tuta absoluta (Lepidoptera: Gelechiidae), a major pest of tomato (Solanum lycopersicum). However, the attractive compounds used by the parasitoid to locate T. absoluta on host plants are not known. We therefore performed behavioural assays and chemical analyses to investigate the chemical basis of interactions between the parasitoid, the tomato plant and T. absoluta. Y-tube olfactometer bioassays revealed that D. gelechiidivoris was attracted to T. absoluta larvae-infested tomato plant volatiles and preferred volatiles of plants with a high infestation level than those with a low infestation level. The parasitoid was also attracted to volatiles of larval frass and to the sex pheromone of T. absoluta. Coupled gas chromatography–mass spectrometric analyses were performed on plant and frass volatiles. We found both qualitative and quantitative differences in volatile emission between healthy and T. absoluta larvae-infested tomato plants, where volatile emission rate increased with increasing infestation level. The most characteristic volatile compounds which distinguished T. absoluta larvae-infested plants from healthy plants were α-pinene, sabinene, β-myrcene, 2-carene, α-phellandrene, 3-carene, α-terpinene, β-phellandrene, (Z)-β-ocimene, (E)-β-ocimene, allo-ocimene, (E)-β-caryophyllene and methyl salicylate. With the exception of caryophyllene oxide, all larval frass volatile compounds were also found in tomato plant headspace volatiles. Olfactometer bioassays using synthetic compounds revealed that D. gelechiidivoris was attracted to α-pinene, β-myrcene, α-phellandrene, α-terpinene, β-ocimene, methyl salicylate and (E)-β-caryophyllene, and the 7-component blend of these attractants elicited the greatest attraction in the parasitoid. These findings open new avenues for exploiting these attractants as kairomone-based lures to recruit and retain the parasitoid in tomato fields for the biological control of T. absoluta. [ABSTRACT FROM AUTHOR]