In haplodiploid organisms, virgin females can produce offspring, albeit only sons. They may therefore face a trade-off between either: (1) searching for hosts and producing sons immediately; or (2) searching for mates and perhaps producing both sons and daughters later in life. Although this trade-off raises a theoretical interest, it has not been approached experimentally. The objective of this article is thus to document the effect of mating status on the foraging behavior of a haplodiploid parasitoid. For this, we recorded the behavior of virgin and mated female Lysiphlebus testaceipes (Hymenoptera: Braconidae) after being released, in the field, on a colony of their aphid hosts. Half of the virgin females were mated by a wild male after less than 10 min of foraging. Evidently, virgin females attract males while foraging on host patches, so that the two activities are not mutually exclusive. Nonetheless, virgin females stayed motionless more often and for longer periods than mated females. Consequently, they attacked aphids at a lower rate, and in turn, attacked fewer aphids on each patch. Moreover, contrary to mated females, virgins did not aggregate their progeny on large patches. We conclude that in L. testaceipes, the trade-off may not be as hypothesized. By dispersing across patches more than mated females, virgins could promote future mating opportunities for their sons and increase their inclusive fitness. However, by moving too frequently, females may lose immediate mating opportunities for themselves and the immediate advantage of producing offspring of both sexes. The observed behavior of virgin L. testaceipes females on host patches could reflect an optimal solution to such a trade-off.

The role of volatile stimuli in the host-searching behaviour of the two parasitoid species Lysiphlebus testaceipes Cresson and Aphidius colemani Viereck (Hymenoptera: Braconidae) was studied in relation to the host Aphis gossypii Glover (Homoptera: Aphididae) on cucumber plants, Cucumis sativa L. (Cucurbitaceae). Experiments were carried out in the laboratory in a wind tunnel, exposing individual parasitoids to signals from three sources simultaneously: (1) a complex of cucumber plants, Cucumis sativa, and A. gossypii; (2) uninfested cucumber plants; and (3) dummy cardboard plants. The flight response of the female parasitoids was considered oriented when they landed on plants and non-oriented when the females landed elsewhere (tunnel floor, sides, or top). Results showed that the proportion of oriented flights was significantly higher than non-oriented flights. A comparison between the two wasp species suggested that A. colemani females may be better able to locate plants than L testaceipes, as the proportion of females that made an oriented flight was higher in this species. For females of both wasp species which made an oriented flight, landing was more often observed on real plants (i.e., with no difference between infested and uninfested plants), than on dummy plants. A description of the flight behaviour of the two parasitoid species is presented. One difference between the species was that flight duration was higher in L. testaceipes than in A. colemani. This work shows that the two parasitoid species respond to stimuli from the host-plants of A. gossypii in a similar way to parasitoids of aphid pests in other crop

Ethological aspects and chemical communication at close-range between the sexes of Lysiphlebus testaceipes Cresson (Hymenoptera: Braconidae) have been investigated through behavioral bioassays and chemical analysis. The attractiveness toward males of whole-body extracts of females and males in hexane and acetone was evaluated, adopting male fanning behavior as a key behavioral component. Also, the activity of polar and nonpolar fraction of female-body extract in hexane obtained using solid-phase extraction technique was investigated. In order to identify cuticular compounds, male and female whole-body extracts with hexane and acetone were analyzed by gas chromatography-mass spectrometry. The results showed that males exhibit a behavior including 4 phases when exposed to virgin females: premount, mount, copulation, and post-copulation. A preliminary courtship of the male included wing fanning, an extension and vibration of the wings for 1 to 2 seconds. Also, some original aspects not described for other species were carried out. The average duration of the entire sequence of events was 138.80 ± 19.51 sec. Also, males displayed significantly more wing fanning behavior in response to female whole-body hexane extracts (70.83%) than female whole-body acetone extracts (33.3%). Furthermore, males did not respond to male-body extracts or to the control (pure hexane and acetone), suggesting that the sex pheromone is composed of cuticular hydrocarbons that are also involved in the male courtship behavior. When hexane extracts of whole females were fractionated on silica gel and exposed to males, more activity was recorded for the nonpolar fraction (50.0%) than the polar fraction (27.7%), but no significant statistical difference was found. Significant differences were detected comparing the control (not fractionated extract) with the polar fraction, but not with the nonpolar fraction. A homologous series of n-alkanes with chain lengths from C19 to C30 carbon atoms was identified and quantified in the solvent extracts of wasp males and females. Between male and female extracts, there was a statistically significant difference in the average quantity of some of these hydrocarbons, such as C27, C28, and C29.

Abstract. Studies were carried out on some biological and behavioral aspects of Cirrospilus diallus Walker and Cirrospilus pictus (Nees) (Hymenoptera: Eulophidae) in relation to their host, the citrus leafminer (CLM), Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae). Adults of both species fed with sugar lived on average 4.45±0.19 days, whereas adults provided with honey survived on average 40.62± 1.97 days. Rates of host mortality due to parasitoid stings without oviposition were as high as 31.25 and 37.73% for C. pictus and C. diallus, respectively. Both species showed arrhenotokous parthenogenesis. Sex ratios of parasitoids emerging from the 2nd and 3rd instar host larvae were male biased, whereas from the 4th instar larvae and pupae sex ratios were female biased. For both species, the duration of the development time of egg, 2nd-3rd instar larva and pupal stages was influenced mainly by temperature. C. diallus required 17-18 days at 26°C to complete development from egg to adult. C. pictus required 11, 16 and 21 days at 26, 21 and 16°C, respectively. A brief description of courtship and mating (only in C. pictus), female oviposition and larval behaviour is reported.

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