A male sex pheromone in a parasitic wasp and control of the behavioral response by the female's mating status

Abstract

SUMMARY Male insects may increase their chance of successful reproduction by releasing pheromones that attract females or elicit sexual acceptance. In parasitic wasps, male pheromones have been suggested for a few species but no chemicals have been identified so far. Here we report the first identification of a male sex pheromone in parasitic Hymenoptera. In abdomens of male jewel wasps, Nasonia vitripennis Walker, we found a mixture of(4R,5R)- and(4R,5S)-5-hydroxy-4-decanolide (HDL), which was released intermittently and attracted virgin females, but no males, in an olfactometer bioassay. However, only a few minutes after copulation mated females avoided the male-derived pheromone. Neither preference nor avoidance was shown by mated females after 24 h and even after they had been allowed to oviposit for 6 days. Nasonia vitripennis females normally mate only once. Thus,their variable response to the sex attractant depending on the mating status makes sense from an evolutionary perspective. Firstly, it increases the chance of virgins to be inseminated. Secondly, by terminating the response or even avoiding the male pheromone, mated females decrease the probability of encountering males and being disturbed by their courtship activities when searching for new oviposition sites.

How parasitoid females produce sexy sons: a causal link between oviposition preference, dietary lipids and mate choice in Nasonia

“…Nasonia vitripennis occurs in two ecotypes, one found in the nests of hole-breeding birds, the other living on and near decaying carcasses [33]. Males of N. vitripennis attract females by releasing a substrate-borne sex pheromone consisting of a mixture of (4R,5R)-and (4R,5S)-5-hydroxy-4-decanolides (HDLs) [34]. The response is shown by virgin females only [34][35][36] and is synergized by the trace component 4-methylquinazoline [37].…”

An epoxide hydrolase involved in the biosynthesis of an insect sex attractant and its use to localize the production site

“…We determined the site of biosynthesis to be the rectal vesicle because this gland contained both HDL and the minor pheromone component 4-MQ (37,38). The line of arguments of our integrative study was closed by the gender-specific cell localization of Nasvi-EH1 gene transcripts in male rectal papillae, which, like the final product HDL, were disrupted by injection of dsRNA into the male abdomen.…”

“…Abdomen and gland extracts were analyzed by GC-MS, using the instrumentation and conditions described in ref. 37. Quantification of pheromone components in the extracts was done by relating their peak areas to the internal standard.…”

“…Females of this parasitic wasp lay their eggs into the puparia of cyclorraphous fly species, where hatching larvae develop gregariously feeding on the host pupa (36). Males of N. vitripennis release a mixture of (4R,5R)-(Athreo-) and (4R,5S)-(Aerythro-)5-hydroxy-4-decanolide (HDL) to attract females (37). This response is shown by virgin females only and is synergized by the trace component 4-methylquinazoline (4-MeQ) (38).…”

Love hangover

“…In rodents, exposure to dominant-male pheromones induces a female preference for dominant versus subordinate males that may involve introduction of new neurons into neural circuits 7 . Similarly, female jewel wasps change their response to male sex pheromones from attraction to aversion after mating 8 , and in D. melanogaster mated females will actively reject courtship, kicking and running away from a new male 9 . This type of 'mate guarding' does not require the continued presence of the successful male, maximizing his ability to mate with other females while still protecting his DNA investment.…”