Dynamics of eupyrene and apyrene sperm storage in ovipositing females of the swallowtail butterfly Papilio xuthus (Lepidoptera: Papilionidae)

Abstract

A male swallowtail butterfly, Papilio xuthus , transfers both eupyrene and apyrene sperm during copulation, both of which migrate to the spermatheca via the spermatophore in the bursa copulatrix of the female. Because the spermatheca seems to remain constant in size during the female lifespan, the excess sperm migration may cause the spermatheca to overflow. Approximately 9000 eupyrene and 265 000 apyrene spermatozoa were transferred during a single copulation, and approximately 1000 eupyrene and 1100 apyrene spermatozoa successfully arrived in the spermatheca. The number of both types of spermatozoon decreased in the spermatheca after the onset of oviposition, and no eupyrene spermatozoa were found by 7 days after copulation, partly due to insemination. The spermathecal gland leading from the distal end of the spermatheca was gradually filled by eupyrene spermatozoa. Although the function of the gland remains unclear, the final destination of the sperm is likely to be the gland.

Motility and dynamics of eupyrene and apyrene sperm in the spermatheca of the monandrous swallowtail butterfly Byasa alcinous

“…A similar decline is reported for the monandrous swallowtail butterfly Battus philenor . Watanabe & Hachisuka (2005) report the disappearance of apyrene sperm from the spermatheca moving forward toward the tip of the spermathecal gland in the polyandrous swallowtail butterfly P. xuthus. Because monandrous (a) (b) Fig.…”

“…A similar decline is reported for the monandrous swallowtail butterfly Battus philenor (Konagaya et al , ). Watanabe & Hachisuka () report the disappearance of apyrene sperm from the spermatheca moving forward toward the tip of the spermathecal gland in the polyandrous swallowtail butterfly P. xuthus . Because monandrous butterflies also have a single spermathecal gland, the sperm dynamics in the spermatheca after sperm migration are not so different between polyandrous and monandrous species.…”

“…However, in the present study, approximately 11 000 apyrene spermatozoa remain in the spermatheca 8 days after the termination of copulation, similar to several polyandrous butterflies such as P. napi (Cook & Wedell, ). For P. xuthus , Watanabe & Hachisuka () report that approximately 200 out of 10 000 migrated apyrene sperm remain in the spermatheca of females 7 days after copulation. Therefore, females of B. alcinous store a much larger number of apyrene sperm in the spermatheca than female polyandrous butterflies.…”

Pattern of sperm storage and migration in the reproductive tract of the swallowtail butterfly Papilio xuthus: cryptic female choice after second mating

“…Rutowski et al (1981) state that if a mated female remates before the migration of the first male's sperm to the spermatheca, the first spermatophore is pushed from the entrance to the rear of bursa copulatrix, and then the second spermatophore is in the correct position to release sperm to fill the spermatheca. However, both types of sperm in P. xuthus migrate from the spermatophore to the spermatheca within 1 day of the termination of copulation (Watanabe & Hachisuka, 2005). The present study also shows that sperm migration ends 24 h after the termination of copulation.…”

Spermicide, cryptic female choice and the evolution of sperm form and function

“…, 2003), parasperm have been observed to disappear from the female tract long before eusperm. Also, in the butterfly Papilio xuthus , <1% of inseminated parasperm reach storage compared with 11% of eusperm (Watanabe & Hachisuka, 2005), and in Pieris napi eusperm are more than twice as likely to reach storage and remain there as parasperm (Cook & Wedell, 1999). These results suggest that parasperm may be neutralized more easily or preferentially in these species.…”