Matings without spermatophore transfer and with transfer of two spermatophores in Callophrys xami (Lycaenidae)

摘要

In Lepidoptera, males normally transfer one spermatophore during copulation (Drummond 1984). However, some studies indicate that in some matings no spermatophore is transferred (although this does not necessarily means that the female is not inseminated; Drummond 1984). There are several possible explanations for this fact: (a) exhaustion of substances necessary for building spermatophores as a result of frequent mating (Drummond 1984); (b) male or female disabilities, such as deformations in filegenitalia or in the reproductive tract resulting from disease or defective development; or (c) mate choice (rejection) after initiation of copulation by females (i.e., females somehow inhibit or prevent the transfer of spermatophores by certain males; Eberhard 1996) or by males (i.e., males avoid to transfer spermatophores to certain females). Mate rejection could be achieved by interrupting copulations before successful sperrnatophore transfer; in this case copulations are expected to be of short duration (Cordero 1993). On the other hand, it has been found that sometimes males transfer more than one spermatophore in one copulation (Drummond 1984). This type of mating may be a male adaptation to sperm competition if the transfer of multiple spermatophores decreases female receptivity during a longer period (in several species there is a negative correlation between female receptivity and the degree of distention of the corpus bursa) (Drummond 1984) or if permits the transfer of more sperm (for example, if spermatophores earl contain only a certain maximum amount of sperm). However, the transfer of multiple spermatophores may be disadvantageous for many species, since the last spermatophore needs to be at least partially digested before re-mating because sperm migration to the spermatheca requires proper alignment of the spermatophore tube with the ductus seminalis and this alignment is more difficult in the presence of another spermatophore (Drummond 1984, Simmons & Siva-Jothy 1998). Thus, an alternative hypothesis is that the transfer of more than one spermatopbore in one copulation is result of a male disability.