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The haplodiploid sex determination of honey bees and the multiple mating of queens pose challenges in determining the genetic contribution of drones (male honey bees). This is especially important for breeding programs as, for example, when attempting to reinforce traits governing social immunity against pests and diseases. Here, we focused on breeding aiming at enhancing hygienic behavior, a trait that is known to reduce parasite load in honey bee colonies. To evaluate the contribution of drones versus queens to this trait, we conducted a two-step bidirectional selection program. First, we selected colonies with consistent phenotypes for low- or high-hygienic behavior (generation P). From those, we generated two types of daughter colonies (F1). One type originated from queens that had been artificially inseminated with selected drones that originated from queens of either low- or high-hygienic phenotype. The other type of colonies was set from naturally mated queens. We then compared the hygienic performance of the progeny colonies. In the next step, we used the F1 colonies (from either artificially inseminated or naturally mated queens) to produce naturally mated queens, which subsequently generated F2 colonies. These were then examined for the level of hygienic behavior. The results demonstrate the significant contribution of both parents to the phenotype of offspring. In particular, drones had a consistent and significant influence on the hygienic performance of the progeny throughout generations. These findings emphasize the great potential to propagate the hygienic trait in local populations by selecting lines for drones that carry the high-hygienic trait.

Males of social Hymenoptera spend the first days following eclosion inside the nest before dispersing to find a young queen to mate with. During this period, they must acquire enough nutrients to enable their sexual maturation and store energy to sustain them through their nuptial journey. It was previously argued that adult hornets are unable to process dietary proteins and rely on the larvae to supply them with free amino acids and carbohydrates that they secrete via trophallaxis. Using isotopically enriched diets, we examined nutrient allocation and protein turnover in newly-emerged males of the Oriental hornet during their maturation period and tested the protein digestion capability in the presence and absence of larvae in both males and worker hornets. The results indicated that protein turnover in males occurs during the first days following eclosion, while carbohydrates are incorporated into body tissues at higher rates towards the end of the maturation period. Additionally, we found that males cannot digest protein and depend on larval secretions as a source of nutrition, while workers, in contrast to previous reports, can metabolize protein independently. Our findings demonstrate the contribution of adult male nutrition and larval secretions to colony fitness.

The main challenge facing a parasite of social insects lies in deceiving its host&rsquo, s detection and defense systems in order to enter and survive within the host colony. Sphecophaga orientalis is an ichneumonid wasp that parasitizes the pupae of the Oriental hornet Vespa orientalis. In Israel&rsquo, s Mediterranean region, this parasitoid infects on average 23.48% (8&ndash, 56%) of the host pupal cells. Observation of colonies brought to the laboratory revealed that the parasite moves around within the colony without being aggressed by the host workers. To assess how the parasite evades host detection and defense, we compared the cuticular hydrocarbon (CHC) profiles of both species. There was little similarity between the parasite and the host workers&rsquo, CHC, refuting the hypothesis of chemical mimicry. The parasite&rsquo, s CHCs were dominated by linear alkanes and alkenes with negligible amounts of branched alkanes, while the host workers&rsquo, CHCs were rich in branched alkanes and with little or no alkenes. Moreover, the parasite cuticular wash was markedly rich in oleic acid, previously reported as a cue eliciting necrophoric behavior. Since nests of Oriental hornets are typified by large amounts of prey residues, we suggest that, due to its unfamiliar CHCs and the abundance of oleic acid, the parasite is considered as refuse by the host. We also detected rose oxide in the parasitoid head extracts. Rose oxide is a known insect repellent, and can be used to repel and mitigate aggression in workers. These two factors, in concert, are believed to aid the parasite to evade host aggression.

Honey bees (Apis mellifera) are exposed to a variety of risk factors, but the ectoparasitic mite Varroa destructor and its associated viruses are considered to be the most significant problem worldwide. It has been widely recognized that honey bee stocks resistant to the mites are an essential part of any sustainable long-term management of Varroa. The aim of this study was to evaluate the efficacy of hygienic behavior in a local population of honey bees in order to reduce Varroa infestation. A bi-directional selection for high and low rates of hygienic behavior was carried out in Israel using either queen artificially inseminated or naturally mated. Colonies were screened for performance: population size, honey production, control of Varroa infestation, and the level of hygienic behavior. Furthermore, we examined the costs and benefits of selection using measurements of colony performance. Either way, selected lines should be tested for trade-offs and benefits to ensure their productivity. The selection process revealed that the trait is heritable. Maternal phenotype has a significant effect on Varroa load, as colonies founded by hygienic daughter queens showed a significantly lower parasite load. No major trade-offs were found between the rate of hygienic behavior, honey yield, and population size. Measuring the direct benefits of hygienic behavior through colony performance suggests that breeding for this trait makes bees more resistant to Varroa destructor. These results are promising for our successful local bee breeding programs in a Mediterranean climate.

Simple Summary The wasp Sphecophaga orientalis is a parasitoid of the Oriental hornet (Vespa orientalis) in its subterranean colonies. We describe this parasitoid’s occurrence in hornet nests in Israel and compare the chemical composition of cuticular washes of both species. The dissimilarity between the two excludes the possibility that the parasite uses either camouflage or chemical mimicry to evade host aggression. Because the parasitoid features large amounts of the necrophoric compound oleic acid, we suggest that, due to this compound, the host considers the parasite as refuse and ignores its presence. The parasitoid head also contains rose oxide, a repellent, possibly used to repel aggressive workers and which, combined with its necrophoric odor, enables it to remain in the nest undisturbed. Abstract The main challenge facing a parasite of social insects lies in deceiving its host’s detection and defense systems in order to enter and survive within the host colony. Sphecophaga orientalis is an ichneumonid wasp that parasitizes the pupae of the Oriental hornet Vespa orientalis. In Israel’s Mediterranean region, this parasitoid infects on average 23.48% (8–56%) of the host pupal cells. Observation of colonies brought to the laboratory revealed that the parasite moves around within the colony without being aggressed by the host workers. To assess how the parasite evades host detection and defense, we compared the cuticular hydrocarbon (CHC) profiles of both species. There was little similarity between the parasite and the host workers’ CHC, refuting the hypothesis of chemical mimicry. The parasite’s CHCs were dominated by linear alkanes and alkenes with negligible amounts of branched alkanes, while the host workers’ CHCs were rich in branched alkanes and with little or no alkenes. Moreover, the parasite cuticular wash was markedly rich in oleic acid, previously reported as a cue eliciting necrophoric behavior. Since nests of Oriental hornets are typified by large amounts of prey residues, we suggest that, due to its unfamiliar CHCs and the abundance of oleic acid, the parasite is considered as refuse by the host. We also detected rose oxide in the parasitoid head extracts. Rose oxide is a known insect repellent, and can be used to repel and mitigate aggression in workers. These two factors, in concert, are believed to aid the parasite to evade host aggression.

Can plants sense natural airborne sounds and respond to them rapidly? We show that Oenothera drummondii flowers, exposed to playback sound of a flying bee or to synthetic sound signals at similar frequencies, produce sweeter nectar within 3 min, potentially increasing the chances of cross pollination. We found that the flowers vibrated mechanically in response to these sounds, suggesting a plausible mechanism where the flower serves as an auditory sensory organ. Both the vibration and the nectar response were frequency-specific: the flowers responded and vibrated to pollinator sounds, but not to higher frequency sound. Our results document for the first time that plants can rapidly respond to pollinator sounds in an ecologically relevant way. Potential implications include plant resource allocation, the evolution of flower shape and the evolution of pollinators sound. Finally, our results suggest that plants may be affected by other sounds as well, including anthropogenic ones. published