COURTSHIP BEHAVIOUR OF NASONIA VITRIPENNIS: HEAD NODDING, MOUTH‐PART EXTRUSION AND PHEROMONE DISCHARGE BY ABDOMECTOMIZED MALES

Abstract

Courting males of the parasitic wasp Nasonia vitripennis appear to release a pheromone with the extrusion of mouth parts during so-called head-nodding behaviour. This pheromone provokes sexual receptivity in conspecific virgin Q $. Abdomectomized c~ c~ court readily but have lost the ability to induce receptivity. Head nodding, mouth-part extrusion, and presumably also pheromone discharge, are absent from their courtship behaviour. However, plugging the injury results in reappearance of these motor patterns, and restores courtship success to the level of intact controls. We present some evidence for a hydraulic system involved in pheromone discharge (with head nodding and mouth-part extrusion). At the same time we present evidence, based on comparative data, that this system is unlikely to be a simple "on-and-off" type behaviour.

Characterization of male‐biased fatty acid desaturase in the jewel wasp Nasonia vitripennis and its role in pheromone production

“…First, the abdomen dipping frequency showed similar change trends to the protein level of SCD5a either along with the aging process or between unmated and mated males. Considering abdomen dipping behavior should be highly associated with attracting pheromone synthesis and release (van den Assem et al, 1981), we considered that linoleic acid for attracting pheromone production may also originated from the head (Ruther et al, 2011; Steiner & Ruther, 2009). Second, qPCR results indicated a significantly higher level of EH1 in head than in abdomen, indicating that the third step for attracting pheromone synthesis, from 12,13‐epoxy‐octadec‐9Z‐enpic acid to (12R,13S)−12,13‐dihydroxy‐octadec‐9Z‐enoic acid (Figure 1) might mainly take place in head than in abdomen.…”

“…For males, greater reproductive success results from mating with females (Steiner & Ruther, 2009; van den Assem et al, 1981), while for virgin females, their response to pheromones is dose‐dependent, preferring males with higher pheromone stocks (Blaul & Ruther, 2011; Ruther et al, 2009). Increased SCD5a protein level and abdomen dipping frequency from Day 1 to Day 3 suggested that aged males might release more attracting pheromone and possess a higher possibility of successful mating.…”

“…Next, males identify intraspecific females according to their cuticular hydrocarbons or lipids (Blomquist & Bagnères, 2010; Howard & Blomquist, 2005; Lockey, 1988), and release oral sex pheromones (courtship pheromone) onto the female's antenna by continuously squeezing their mouthparts on the female's back to courtship. If successful, virgin females will show receptivity, and copulation follows (van den Assem et al, 1980, 1981). After mating, males return to the female's back and orally release another batch of pheromones (postmating pheromone, or blocking pheromone) on the female's antenna, which can inhibit females from mating with other males.…”

The chemical basis of mate recognition in two parasitoid wasp species of the genus Nasonia

“…After copulation, males perform post‐copulatory courtship including additional series of head‐nodding behavior. A detailed analysis of the courtship behavior in the four Nasonia species revealed some subtle species‐specific differences (van den Assem & Vernel, ; van den Assem et al., , ; van den Assem & Werren, ). Although not completely strict, the females’ choosiness has the potential of playing a major part in maintaining prezygotic reproductive isolation between sympatric Nasonia species.…”