DURATION OF COPULATION IN 
POANES HOBOMOK 
(LEPIDOPTERA: HESPERIIDAE) 
AND SOME BROADER SPECULATIONS* 
By John M. Burns 
Museum of Comparative Zoology, Harvard University 
Many aspects of diurnal lepidopteran reproductive biology are 
still poorly known. Duration of copulation — an awkward phrase 
which, for convenience, is here symbolized T f — can readily be de- 
termined in various species but rarely has been. It is of interest 
not only as a behavioral element of possible taxonomic value but 
also as a highly critical time in the life cycle : copulation is, of course, 
required for insemination ; but copulating individuals, being mutually 
occupied and encumbered, must often be more vulnerable to preda- 
tion than separate ones are. Since the act of copulation is vital for 
contributing genetic material to the succeeding generation but is 
not performed without risk, one may ask, What fraction of adult 
life is, on an average, spent copulating? Answers depend on knowing 
such attributes as Tf and mating frequency, as well as adult longev- 
ity for each sex. 
Progress has recently been made in gathering comparative data 
on mating frequency by counting spermatophores dissected from 
reproductive tracts of wild females and in interpreting these data 
(Burns 1966, 1968; Shields 1968; Pliske, in prep.). On the other 
hand, T f has received scant attention. Scattered observations include 
the following. An interspecific copulation involving pierid butterflies, 
Colias interior cf X C. eurytheme 9, lasted 67 minutes (Ae 1956). 
Among crosses of C. eurytheme carried out to study the genetics of 
an intricate enzyme polymorphism (Burns and Johnson 1967), the 
two that were timed gave Tf s of 55 and 75 minutes. In Danaus 
plexippus, a nymphalid butterfly, “It is not known for what length 
of time the male and female remain . . . united, but on one occasion 
such a pair was found an hour and a half later on the same tree 
and in the same position” (Urquhart i960). A related species, D. 
gilippus, copulates for a period of about one to (usually) several 
hours (Brower, Brower and Cranston 1965). Indeed, timed copula- 
*Published with the aid of a grant from the Museum of Comparative 
Zoology at Harvard College. 
Manuscript received by the editor December 10, 1969 
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