The Role of Cuticular Hydrocarbons in Male Mating Behavior of the Mustard Leaf Beetle, Phaedon cochleariae (F.)

Abstract

We investigated the role that cuticular hydrocarbons (CHC) play in sexual communication by the mustard leaf beetle, Phaedon cochleariae (Coleoptera: Chrysomelidae). In laboratory bioassays, male P. cochleariae attempted to copulate with living or freeze-killed females as often as with males. However, the duration of copulation with females was longer than with males. To elucidate the impact of CHC on this behavior, cuticular compounds of adults of both sexes were extracted with dichloromethane. Male mating attempts with glass beads treated with the dichloromethane extract were nearly as frequent as with living beetles. The dichloromethane extract was fractionated by silica gel chromatography, and the biological activity of the fractions was tested by applying them to glass beads. A non-polar hexane fraction significantly elicited mating behavior, whereas the polar methanol fraction did not, likely because it contained defensive compounds from exocrine glands located in the elytra and pronota. Interestingly, a mixture of both the non-polar and polar fraction tended to elicit more mating attempts than did the non-polar hexane fraction alone. Further fractionation of the significantly active hexane fraction by silver nitrate column chromatography revealed that saturated CHC elicited mating behavior, but the olefins did not. GC-MS analyses of dichloromethane cuticular extracts showed that the male and female CHC profiles were qualitatively identical, but differed in their relative composition. Canonical discriminant analysis showed that CHC profiles of males and females formed separate clusters. Nevertheless, the results of our bioassays demonstrated that male and female CHC did not elicit sex discriminative male behavior, but induced mating by males regardless of the sex of the partner.

Mating Sequence and Evidence for the Existence of a Female Contact Sex Pheromone in Brontispa longissima (Coleoptera: Chrysomelidae)

“…Since the five phases of male behavior are conducted step by step, this mating sequence is considered to be behavior formulated with extremely high probability. Similar mating sequences were observed after encounters between males and females in several other Chrysomelidae: L. decemlineata 9,13,16 , G. atrocyanea 19 , and P. cochleariae 5 . When the male B. longissima attempted to mate, some females walked away.…”

“…However, among the Chrysomelidae, the presence of contact sex pheromones has been reported in only a few species: the Colorado potato beetle, Leptinotarsa decemlineata 9,13,16 , the Japanese green duck leaf beetle, Gastrophysa atrocyanea 19 , the blue milkweed beetle, Chrysochus cobaltinus 18 , the dogbane leaf beetle, Chrysochus auratus 18 , and the mustard leaf beetle, Phaedon cochleariae 5 . Although contact sex pheromones play an important role in mating behavior, they have been chemically identified in only one species, G. atrocyanea 19 .…”

Böcek yumurtası ve konukçu bitki arasındaki karşılıklı ilişkiler

“…Örneğin, Phyllotreta albionica (J. L. LeConte) (Coleoptera: Chrysomelidae) yaprağı mum tabakası ile kaplı olan lahana çeşitlerinde, mum tabakası ile kaplı olmayan çeşitlere göre daha az zarar yaptığı, bazen de hiç zarar yapamadığı, böylelikle de yumurta bırakımında bir azalma olduğu gözlenmiştir (Pehlivan, 1978). Böceklerin bitki üzerine yumurta bırakması, yukarıda da değinildiği gibi, bitki tarafından çeşitli morfolojik yollarla engellendiği gibi, bazı kimyasal yollarla da engellenebilmektedir (Hilker et al, 2002;Stotz et al, 2002;van Poecke & Dicke, 2002;Traw & Bergelson, 2003;Bruinsma et al, 2007;Geiselhardt et al, 2009;Zhao et al, 2009;Hilker & Meiners, 2011;Chamarthi et al, 2011;Fürstenberg-Hägg et al, 2013;War et al, 2013).…”

“…Örneğin, Phaedon cochleariae (F.) (Coleoptera: Crysomelidae)'nin kütikülar hidrokarbon profili, üzerinde beslendiği konukçu bitki türleri tarafından önemli bir şekilde etkilenir. Yapılan bir çalışmada bu türe ait iki farklı konukçu bitki (Çin lahanası, tere) üzerinde beslenen iki farklı erkek birey grupları çiftleşmek için, aynı konukçu bitki türü üzerinde beslenen dişi bireyleri, 4 farklı konukçu bitki türü üzerinde beslenen dişi bireylere göre daha çok tercih etmiştir (Geiselhardt et al, 2009). Ayrıca yine aynı çalışmada, erkek bireylerin, tercih edilen dişi bireylerin kütikülar hidrokarbon ekstraktı ile muamele edilmiş cam mankenlerle daha sık çiftleşme girişiminde bulunduğu gözlenmiştir (Geiselhardt et al, 2009).…”

Reflectance-based identification of parasitized host eggs and adult Trichogramma specimens

“…A recent review article claims that UAVs (unmanned aerial vehicles) will revolutionize research methods in spatial ecology (Anderson (Dowell et al, 1999;Roux et al, 2008), (2) in relative composition (Geiselhardt et al, 2009) or in actual composition (Howard and Pérez-Lachaud, 2002) among males and females within a species, (3) during the lifespan of insect individuals (Butler et al, 2009;Howard and Baker, 2003;Lapointe et al, 2004;Roux et al, 2008;Zhu et al, 2006), (4) among eusocial individuals with different tasks (Ferreira-Caliman et al, 2010;Nunes et al, 2009), (5) according to mating behavior and status (Howard and Baker, 2003;Howard and Pérez-Lachaud, 2002;Steiner et al, 2007), and (6) in response to environmental conditions (Howard and Baker, 2003;Howard and Pérez-Lachaud, 2002;De Loof et al, 2010). Thus, there is ample evidence of the composition of the insect cuticula being highly dynamic and tightly associated with complex internal physiological processes in insects.…”