Male pheromones were found in many Lepidopteran species, but they have been receiving less attentions than female pheromones [1]. Male pheromones distribute widely in Lepidoptera. In diurnal Lepidoptera, including butterflies and a few moth species, sexual behaviors are most likely rely on male pheromones and visual cues, therefore female don’t have sex pheromone glands [2, 3]. In nocturnal Lepidopteran species, male pheromones were also found to have similar functions with female pheromones [4]. Thus male pheromones might have equally important role as female pheromones in Lepidoptera.
Males of several butterfly species emit odors that are detectable even by the human nose [5]. More than 120 components were identified from wings of Pieris rapae and Pieris brassica, and some of them were shown to be aphrodisiac pheromones in insects of other orders [6]. P-cresol was identified as an aphrodisiac pheromone component in Erynnis montanus [5]. In Pieris napi, citral makes females accept males during courtship [7]. Studies in Ostrinia nubilalis showed that male pheromones function as a display trait influencing mating success, and compositions of male pheromones have relationship with male age [4]. In Bicyclus anynana, males in different age have different composition of male pheromones [8]. Courting males at different ages displayed large differences of one pheromone component, Hexadecanal. Analyses on titres and ratios of male pheromone components showed that the male pheromone compositions are strongly correlated with male age and individuality. Different males with different ages, or even different single male with same ages more or less release different compositions of male pheromones. Mid-aged male receiving higher mating success then young male indicated that females prefer to mate with mid-aged over younger males. By applying different compositions of synthetic male pheromones onto same operated males, it was identified that the ones applied mid-age perfume was shown to have higher mating rate [1, 8].
Besides sexual selection with females, it has been suggested that male pheromones are used in male-male competitions or other activities. However, male P. napi emitted male pheromone component citral not only when interacting with females, conspecific males and heterospecific males, but also when alone [7]. Amount of male pheromones released when male alone was not significant different with that when male interacting with one conspesific male, or one heterospecific male [7]. Similarly, in the diamondback moth, Plutella xylostella, males did not significantly increase the release of male pheromones in the presence of increasing numbers of competitors [9]. These results suggest that the role of male pheromones in male-male competitions is still unsure.
All in all, male pheromones show the specific characters of males and might play important roles in sexual selections [4, 8]. Male pheromones should be payed more attentions as well as female pheromones.
References
[1] Caroline MN, Helene de Vos, Maria V. Schneider, Lassance JM, Estramil N, Andersson J, Bang J, Hedenstrom E, Brakefield PM. (2008) The Male Sex Pheromone of the Butterfly Bicyclus anynana: Towards an Evolutionary Analysis. PLoS ONE July-2008-3-7-e2751
[2] Victor Sarto i Monteys, Patricia Acin, Gloria Rosell, Carmen Quero, Miquel A. Jimenez, Angel Guerrero (2012)Moths Behaving like Butterflies. Evolutionary Loss of Long Range Attractant Pheromones in Castniid Moths: A Paysandisia archon Model . PLOS ONE. DOI: 10.1371/journal.pone.0029282
[3] KonDo Yusuke; Naka Hideshi; Tsuchida Koji. (2012) Pheromones and body coloration affect mate recognition in the Japanese nine-spotted moth Amata fortunei (Lepidoptera: Arctiidae) . JOURNAL OF ETHOLOGY DOI: 10.1007/s10164-012-0327-z
[4] Lassance JM & Christer L. (2009) Concerted evolution of male and female display traits in the European corn borer, Ostrinia nubilalis. BMC Biology. doi: 10.1186/ 1741- 7007-7-10
[5] Omura Hisashi; Honda Keiichi. (2011) Pungent odor of the adult skipper butterfly Erynnis montanus (Lepidoptera: Hesperiidae). APPLIED ENTOMOLOGY AND ZOOLOGY. DOI: 10.1007/s13355-011-0039-9
[6] Yildizhan Selma; van Loon Joop; Sramkova Anna. (2009) Aphrodisiac Pheromones from the Wings of the Small Cabbage White and Large Cabbage White Butterflies, Pieris rapae and Pieris brassicae. CHEMBIOCHEM . DOI: 10.1002/cbic.200900183
[7] Andersson J, Anna-KB-K, Vongvanich N and Christer W. (2007) Male sex pheromone release and female mate choice in a butterfly. The Journal of Experimental Biology 210, 964-970
[8] Caroline MN, Klaus Fischer, Saastamoinen M, Allen CE, Wallin EA, Hedenstrom E and Brakefield PM. (2012) Cracking the olfactory code of a butterfly: the scent of ageing. ECOLOGY LETTERS. DOI: 10.1111/j.1461-0248.2012.01748.x
[9] Davie Lauren C.; Jones Theresa M.; Elgar Mark A. (2010)The role of chemical communication in sexual selection: hair-pencil displays in the diamondback moth, Plutella xylostella. ANIMAL BEHAVIOUR. DOI: 10.1016/j.anbehav.2009.11.015