Limoniic acid is a sex attractant pheromone component of Limonius agonus (Coleoptera: Elateridae)

Recently, (E)-4-ethyloct-4-enoic acid (limoniic acid) has been reported as the major sex attractant pheromone component of L. canus and L. californicus (Coleoptera: Elateridae) in western North America. Our objective was to determine whether limoniic acid is also a sex attractant pheromone component of the eastern field wireworm, Limonius agonus (Say). In gas chromatographic-electroantennographic detection (GC-EAD) analyses of headspace volatiles from L. agonus females, antennae from male L. agonus responded to limoniic acid as a trace component. In field experiments, traps baited with synthetic limoniic acid, or its analog (E)-5-ethyloct-4-enoic acid, afforded captures of male L. agonus 3.6- to 8.9-times greater than unbaited control traps. In long-term field trapping studies, emergence and captures of L. agonus males fluctuated with temperature for more than 5 weeks, with distinctively different emergence patterns at the two study sites. Compared to previous studies with L. canus and L. californicus, limoniic acid as a trap lure afforded relatively low captures of L. agonus males, suggesting that L. agonus populations were low or that other L. agonus pheromone components are yet to be identified

A Meal or a Male: The ‘Whispers’ Of Black Widow Males Do Not Trigger a Predatory Response in Females

Introduction Female spiders are fine-tuned to detect and quickly respond to prey vibrations, presenting a challenge to courting males who must attract a female’s attention but not be mistaken for prey. This is likely particularly important at the onset of courtship when a male enters a female’s web. In web-dwelling spiders, little is known about how males solve this conundrum, or about their courtship signals. Here we used laser Doppler vibrometry to study the vibrations produced by males and prey (house flies and crickets) on tangle webs of the western black widow Latrodectus hesperus and on sheet webs of the hobo spider Tegenaria agrestis. We recorded the vibrations at the location typically occupied by a hunting female spider. We compared the vibrations produced by males and prey in terms of their waveform, dominant frequency, frequency bandwidth, amplitude and duration. We also played back recorded male and prey vibrations through the webs of female L. hesperus to determine the vibratory parameters that trigger a predatory response in females. Results We found overlap in waveform between male and prey vibrations in both L. hesperus and T. agrestis. In both species, male vibrations were continuous, of long duration (on average 6.35 s for T. agrestis and 9.31 s for L. hesperus), and lacked complex temporal patterning such as repeated motifs or syllables. Prey vibrations were shorter (1.38 - 2.59 s), sporadic and often percussive. Based on the parameters measured, courtship signals of male L. hesperus differed more markedly from prey cues than did those of T. agrestis. Courtship vibrations of L. hesperus males differed from prey vibrations in terms of dominant frequency, amplitude and duration. Vibrations of T. agrestis males differed from prey in terms of duration only. During a playback experiment, L. hesperus females did not respond aggressively to low-amplitude vibrations irrespective of whether the playback recording was from a prey or a male. Conclusions Unlike courtship signals of other spider species, the courtship signals of L. hesperus and T. agrestis males do not have complex temporal patterning. The low-amplitude ‘whispers’ of L. hesperus males at the onset of courtship are less likely to trigger a predatory response in females than the high-amplitude vibrations of struggling prey

Almond volatiles attract neonate larvae of Anarsia lineatella (Zeller) (Lepidoptera: Gelechiidae)

Post-diapause overwintered larvae and neonates of any generation of the peach twig borer, Anarsia lineatella (Zeller), seek suitable sites to bore into and mine tissue of their host plants, including almond and peach. We tested the hypothesis that larvae are attracted to the same almond volatiles that elicit antennal responses from adult moths. Of five candidate almond semiochemicals [β-bourbonene, (E,E)-α-farnesene, (E)-β-ocimene, nonanal, decenal] tested singly or in binary combination (nonanal, decenal) in laboratory Y-tube olfactometers, only β-bourbonene attracted neonate larvae. β-bourbonene in combination with (EE)-α-farnesene was as attractive as the complete almond volatile blend, indicating that they are key semiochemicals for foraging larvae

The Innate and Adaptive Immune System of the Common Bed Bug, <em>Cimex lectularius</em>: Current Knowledge and Research Opportunities

The common bed bug, Cimex lectularius (Hemiptera: Cimicidae), is a blood-feeding ectoparasite of vertebrates, primarily humans. In contrast to many other hematophagous arthropods, such as kissing bugs, mosquitoes, sandflies, and ticks that intermittently seek blood meals from vertebrate hosts, C. lectularius does not vector disease-causing pathogens and parasites to their human hosts. In this review, we summarize currently known immune responses by C. lectularius, and propose worthy research topics. Challenged by microbe ingestion or infection, C. lectularius mounts cellular immune responses such as phagocytosis of bacteria, as well as humoral responses such as secretions of antimicrobial peptides into the hemolymph. The functional immune system of the hemimetabolous C. lectularius resembles that of holometabolous insects but exhibits distinct deviations, including a sparser immune repertoire, the production of DNA nets by cells in response to pathogen invasions, and reproductive immune anticipation in the context of sexual reproduction (traumatic insemination). Many components of the C. lectularius immune system still await discovery, including the receptor molecules and immune pathways involved in antiparasitic and antiviral immune responses. Why C. lectularius does not vector pathogens to human hosts is hardly understood. Potential explanations include upregulated antimicrobial peptide activities that help eliminate invading pathogens

Brewer’s yeast, Saccharomyces cerevisiae, enhances attraction of two invasive yellowjackets (Hymenoptera: Vespidae) to dried fruit and fruit powder

The German yellowjacket, Vespula germanica F., and common yellowjacket, Vespula vulgaris L. (Hymenoptera: Vespidae), are pests of significant economic, environmental, and medical importance in many countries. There is a need for the development and improvement of attractive baits that can be deployed in traps to capture and kill these wasps in areas where they are a problem. Yellowjackets are known to feed on fermenting fruit, but this resource is seldom considered as a bait due to its ephemeral nature and its potential attractiveness to nontarget species. We analyzed the headspace volatiles of dried fruit and fruit powder baits with and without Brewer’s yeast, Saccharomyces cerevisiae, using gas chromatography–mass spectrometry, and we field tested these baits for their attractiveness to yellowjackets in Argentina. The addition of yeast to dried fruit and fruit powder changed the volatile compositions, increasing the number of alcohols and acids and decreasing the number of aldehydes. Dried fruit and fruit powder baits on their own were hardly attractive to yellowjackets, but the addition of yeast improved their attractiveness by 9- to 50-fold and surpassed the attractiveness of a commercial heptyl butyrate-based wasp lure. We suggest that further research be done to test additional varieties and species of yeasts. A dried fruit or fruit powder bait in combination with yeast could become a useful tool in the management of yellowjacketsFil: Babcock, Tamara. Simon Fraser University. Department of Biological Sciences; CanadaFil: Gries, Regine. Simon Fraser University. Department of Biological Sciences; CanadaFil: Borden, John. Scotts Canada; CanadaFil: Palmero, Luis. Simon Fraser University. Department of Biological Sciences; CanadaFil: Mattiacci, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas-Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo de Ecología de Poblaciones de Insectos; Argentina.Fil: Masciocchi, Maite. Consejo Nacional de Investigaciones Científicas y Técnicas-Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo de Ecología de Poblaciones de Insectos; Argentina.Fil: Corley, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas-Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo de Ecología de Poblaciones de Insectos; ArgentinaFil: Gries, Gerhard. Simon Fraser University. Department of Biological Sciences; Canad

Compound eyes of the small white butterfly Pieris rapae have three distinct classes of red photoreceptors

The two subspecies of the small white butterfly, the European Pieris rapae rapae and the Asian P. r. crucivora, differ in wing colouration. Under ultraviolet light, the wings of both male and female P. r. rapae appear dark, whereas the wings of male P. r. crucivora are dark and those of females are bright. It has been hypothesized that these sexually dimorphic wing reflections in P. r. crucivora may have induced the evolution of a fluorescing-screening pigment in the violet-opsin-expressing photoreceptors of males, thus facilitating greater wavelength discrimination near 400nm. Comparing the compound eyes of the two subspecies using genetic, microscopical, spectrographic, and histological methods revealed no differences that would meaningfully affect photoreceptor sensitivity, suggesting that the fluorescing-screening pigment did not evolve in response to sexually dimorphic wing reflections. Our investigation further revealed that (i) the peri-rhabdomal reddish-screening pigments differ among the three ommatidial types; (ii) each of the ommatidial types exhibits a unique class of red photoreceptor with a distinct spectral peak; and (iii) the blue, green, and red photoreceptors of P. rapae exhibit a polarization sensitivity >2, with red photoreceptors allowing for a two-channel opponency form of polarization sensitivity

Method for rearing North American yellowjackets

Studying yellowjackets is challenging due to their cryptic nesting behaviour, short field season, and extreme variation in population density. Developing or perfecting techniques for rearing yellowjackets would greatly increase the opportunity of studying the communication ecology of yellowjackets and the evolution of eusociality in the Hymenoptera. Our objective was to assess a method for rearing the five Vespula congeners V. acadica (Sladen), V. alascensis Packard, V. atropilosa (Sladen), V. germanica (F.), and V. pensylvanica (de Saussure). In early spring of 2014, we collected queens of each of the five species from the field and placed them singly in a plywood nest box connected to a mesh cylinder that served as a foraging arena and provided constant access to water and food (honey, live flies, and live caterpillars). For each queen, we recorded nest initiation, the attachment site of the nest pedicel, and the stage of nest development at the end of the experiment, 9 weeks after the last collection date of queens. Queens of V. germanica (n=18), V. alascensis (n=11), V. acadica (n=4), V. pensylanica (n=23) and V. atropilosa (n=11) had nest inititation rates of 61%, 50%, 25%, 17%, and 0%, respectively. The mean number of nest cells built by queens of V. germanica, V. alascensis, V. acadica, V. pensylvanica, and V. atroplisoa were 21.6 ± 4.6, 17.8 ± 6.3, 8.0, 26.5 ± 8.3, and 0, respectively. Two V. germanica queens and one V. pensylvanica queens established nests that produced a few worker wasps. While our rearing method compares favorably to, and in some aspects improves, previous rearing methods, further refinements are needed to generate the large numbers of wasp workers that are essential for experimental testing of hypotheses pertinent to life history traits of yellowjackets