Identification of the contact sex pheromone of Gastrophysa atrocyanea (Coleoptera: Chrysomelidae)

Abstract

The mating behavior of the male Gastrophysa atrocyanea, that is, extrusion of the aedeagus, was elicited by the cuticular hydrocarbons on the surface of the female body. Males attempted to mate with a dummy treated with the female equivalent of the female elytra extracts. After fractionation of the elytra extracts by Florisil column chromatography and reverse phase high performance liquid chromatography, two fractions, consisting mainly of methylheptacosanes and methylnonacosanes were found to elicit the male mating behavior. These compounds, synthetic 9-methylheptacosane, 11-methylheptacosane, 9-methylnonacosane and 11-methylnonacosane, were contained in active fractions and showed high pheromonal activity. Therefore, these monomethylalkanes were considered to be contact sex pheromones of this beetle. However, synthetic 13-methylheptacosane, 13-methylnonacosane and 15-methylnonacosane, positional isomers of active monomethylalkanes, also contained in the active fractions, did not have the activity. A mixture of these seven monomethylalkanes at approximately natural concentrations also had enough activity to elicit the male mating behavior. Furthermore, the results of a bioassay using some related structural monomethylalkanes revealed that the length of the carbon backbone and the position of the methyl branch greatly influenced the pheromonal activity of G. atrocyanea.

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.…”

“…Male contact with the antennae, tarsi, or palpi was considered to be involved in perception of female-specific cues. The importance of direct contact in mating behavior has been demonstrated in other Chrysomelidae: L. decemlineata 9,13,16 , G. atrocyanea 19 , C. cobaltinus 18 , and C. auratus 18 . However, more detailed examinations will be needed to determine the presence of attractant cues in the mating behavior of B. longissima.…”

“…The contact sex pheromone of B. longissima is therefore considered to consist of one or more non-polar compounds, probably saturated hydrocarbon(s). In G. atrocyanea, the monomethyl alkanes 9-methyl heptacosane, 11-methyl heptacosane, 9-methyl nonacosane and 11-methyl nonacosane, 13-methyl heptacosane, 13-methyl nonacosane, 15-methyl nonacosane, and n-alkanes were identified as components of the contact sex pheromone 19 . It will be necessary to elucidate the chemical structure and function of the contact pher- Values in the same response followed by the same letter were not significantly different according to nominal logistic regression analysis.…”

“…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 . Fundamental research is necessary to develop applications using synthetic pheromones; however, biological research concerning mating behavior and sex pheromones is a relatively unexplored area.…”

Deciphering the signature of cuticular lipids with contact sex pheromone function in a parasitic wasp

“…The non-polar CHCs have been extensively investigated over the past three decades with respect to their role as semiochemicals (Howard, 1993;Singer, 1998;Howard and Blomquist, 2005). A multitude of studies have shown that CHCs are not only involved in the diverse interactions of social insects (Greene and Gordon, 2003;Endler et al, 2004;van Zweden and d'Ettorre, 2010) but also used by many solitary insects as contact stimuli when searching for oviposition sites (Colazza et al, 2007;Rostas and Wolfling, 2009;Darrouzet et al, 2010) or sexual mates (Syvertsen et al, 1995;Sullivan, 2002;Steiner et al, 2005;Steiner et al, 2006;Sugeno et al, 2006;Geiselhardt et al, 2009;Ferveur and Cobb, 2010;Ginzel, 2010;Ruther et al, 2011).…”