Antiaphrodisiacs in pierid butterflies: a theme with variation!
ABSTRACT Male Pieris napi butterflies previously have been shown to synthesize and transfer an antiaphrodisiac, methyl salicylate (MeS), to females at mating. This substance curtails courtship and decreases the likelihood of female remating. Here, we show that similar systems occur in Pieris rapae and Pieris brassicae. In P. rapae, 13C-labeling studies showed that males utilize the amino acids phenylalanine and tryptophan as precursors to MeS and indole, respectively. These volatiles are transferred to females at mating and function as antiaphrodisiacs, as demonstrated by field tests entailing painting MeS, indole, or a mixture on the abdomens of virgin females and assessing their attractiveness to wild males. With P. brassicae, 13C-labeling studies showed that males use phenylalanine as a precursor to synthesize benzyl cyanide, which was demonstrated to function as an antiaphrodisiac by field tests similar to those for P. rapae. This communication system exhibits both similarities and differences among the three species; in P. napi and P. rapae, males are fragrant but transfer a volatile antiaphrodisiac to females that is completely different from the male odor, whereas in P. brassicae the antiaphrodisiac transferred by male to female is identical with male odor.
- Biological Reviews 01/2008; 45(4):525 - 567. · 10.26 Impact Factor
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ABSTRACT: Sexual selection theory predicts that the different selection pressures on males and females result in sexual conflict. However, in some instances males and females share a common interest which could lead to sexual cooperation. In the pierid butterfly Pieris napi the male and the recently mated female share a common interest in reducing female harassment by other males soon after mating. Here we show that P. napi males transfer an anti-aphrodisiac to the female at mating, methyl-salicylate (MeS), which is a volatile substance which mated females emit when courted and which makes males quickly abandon them. A 13C-labelling experiment demonstrated that only males synthesize MeS. The effect of this antiaphrodisiac is so strong that most males will refrain from mating with virgin females to whom MeS has been artificially applied. In P. napi, males also transfer nutrients to females at mating. This increases female fecundity and longevity and so females benefit from remating. Hence, sexual cooperation gradually turns to conflict. Future research is required to reveal which sex controls the gradual decrease in the MeS titre which is necessary for allowing mated females to regain attractiveness and remate.Proceedings of the Royal Society B: Biological Sciences 08/2000; 267(1450):1271-5. · 5.68 Impact Factor
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ABSTRACT: Success in sperm competition is of fundamental importance to males, yet little is known about what factors determine paternity. Theory predicts that males producing high sperm numbers have an advantage in sperm competition. Large spermatophore size (the sperm containing package) also correlates with paternity in some species, but the relative importance of spermatophore size and sperm numbers has remained unexplored. Males of the small white butterfly, Pieris rapae (Lepidoptera: Pieridae), produce large nutritious spermatophores on their first mating. On their second mating, spermatophores are only about half the size of the first, but with almost twice the sperm number. We manipulated male mating history to examine the effect of spermatophore size and sperm numbers on male fertilization success. Overall, paternity shows either first male or, more frequently, second male sperm precedence. Previously mated males have significantly higher fertilization success in competition with males mating for the first time, strongly suggesting that high sperm number is advantageous in sperm competition. Male size also affects paternity with relatively larger males having higher fertilization success. This may indicate that spermatophore size influences paternity, because in virgin males spermatophore size correlates with male size. The paternity of an individual male is also inversely correlated with the mass of his spermatophore remains dissected out of the female. This suggests that females may influence paternity by affecting the rate of spermatophore drainage. Although the possibility of female postcopulatory choice remains to be explored, these results clearly show that males maximize their fertilization success by increasing the number of sperm in their second mating.01/1998;