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The article discusses the results of a study that examined the role of the female-released sex pheromones on the courtship behavior of Lysiphlebus testaceipes males. It evaluated the attractiveness toward males of whole-body extracts of females in males in hexane and acetone. Some preliminary courtship behavior of male included wing fanning with an extension and vibration of the wings lasting for 2 seconds.

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 crops. [ABSTRACT FROM AUTHOR]

Flowering plants can be introduced in modern agroecosystems to support resident natural enemies in the context of Conservation Biological Control (CBC). Buckwheat (Fagopyrum esculentum) (Polygonales: Polygonaceae) has been shown to enhance the longevity of several parasitoids through the provision of high quality and easily accessible floral nectar. Yet floral nectar is ubiquitously colonized by microbes which can change nectar chemistry with consequences for parasitoids. Nonetheless, how bacteria associated with buckwheat floral nectar affect parasitoid performance is not known. In this study, adult females of Trissolcus basalis (Hymenoptera: Scelionidae) and Ooencyrtus telenomicida (Hymenoptera: Encyrtidae), two parasitoids of Nezara viridula (Hemiptera: Pentatomidae), were provided with synthetic nectar fermented by 14 bacterial isolates originating from buckwheat nectar. We recorded the effect of bacterial fermentation on female longevity and nectar chemistry. In the case of T. basalis, females consuming nectar fermented by Bacillus sp., Brevibacillus sp., Brevibacterium frigoritolerans, Saccharibacillus endophyticus, and Terribacillus saccharophilus significantly enhanced their longevity compared with females fed with non‐fermented nectar. For O. telenomicida, enhanced longevity was recorded only in the case of B. frigoritolerans and Pantoea dispersa. For both parasitoids, no negative effects due to bacterial fermentation of nectar were recorded. Chemical investigations of bacteria‐fermented nectars revealed an increased diversity in the composition of sugars and sugar alcohols, whereas non‐fermented nectar only contained sucrose. Our findings show that nectar‐inhabiting bacteria are important “hidden players” in the interactions between flowers and parasitoids, an indication that a better understanding of plant–microbe–insect interactions could improve CBC programmes. [ABSTRACT FROM AUTHOR]