|SREL Reprint #1169|
Savannah River Ecology Laboratory, Aiken
Isolation, Sexual Behavior and Pheromones in the Fasciatus Species Group
of the Lizard Genus Eumeces
E. Cooper, Jr. and Laurie J. Vitt
Ethological isolation was found among North American
members of the fasciatus species group of Eumeces.
Ethological isolation was investigated by staging a series of
interspecific and intraspecific heterosexual encounters.
No male E. laticeps or E. fasciatus courted
heterospecific females. In both
species, males courted and copulated with conspecific females in a significantly
higher frequency of trials than with heterospecific females.
However, male E. inexpectatus courted females of all three
species, courting conspecific females and female E. laticeps at
similar frequencies, but female E. fasciatus at a significantly
lower frequency. No females of any
of three species were sexually receptive to heterospecific males, but forced
copulation occur din two of nine courtships of female E. fasciatus
by male E. inexpectatus. Thus,
ethological isolation in the fasciatus group appears to be complete with
the possible exception of occasional forced copulation between male E. inexpecatus
and female E. fasciatus. Preliminary
evidence on the role of chemical stimuli in maintaining ethological isolation
was obtained from experiments involving interspecific transfers of female odors.
Male E. inexpectatus courted female E. fasicatus
labeled with the odor of female E. inexpecatus in a significantly
greater proportion of trials than they courted such females lacking the
conspecific female odor. In a
similar experiment, male E. fasicatus did not court female E.
inexpectatus even if the females bore odors of female fasciatus.
SREL Reprint #1169
Cooper, W.E., Jr. and L.J. Vitt. 1987. Ethological isolation, sexual behavior and pheromones in the Fasciatus species group of the lizard genus Eumeces. Ethology 75:328-336.