Testis size variation in frogs: testing the alternatives |
| |
Authors: | Sharon B Emerson |
| |
Institution: | (1) Department of Biology, University of Utah, Salt Lake City, UT 84112, USA Fax: (801) 581-4668; e-mail: emerson@biology.utah.edu, US;(2) Division of Amphibians and Reptiles, Field Museum of Natural History, Chicago, IL 60605, USA, US |
| |
Abstract: | While sperm competition may be a major factor affecting relative testis size in vertebrates as a whole, additional hypotheses
have not been given much attention in frogs. This is important because sperm competition is relatively uncommon in frogs and
relative testis size varies in frogs that do not have multiple-male breeding systems. This paper tests two additional hypotheses
for differences in relative testis size among frogs: relative clutch size (number of eggs/snout vent length) and androgen
level. Testis size was measured in 90 species of frogs belonging to five families. Relative testis size was found to be positively
correlated with relative clutch size in species that lack sperm competition. Mean androgen levels of species also positively
covaried with relative testis size. However, there was no correlation between relative testis size and level of male agonistic
behavior among species, despite other work indicating that testosterone levels are positively correlated with agonistic behavior
in at least some species. These findings suggest that a number of factors in addition to sperm competition are important in
the evolution of testis size in male frogs.
Received: 17 January 1997 / Accepted after revision: 23 June 1997 |
| |
Keywords: | Sperm competition Testis size Frog |
本文献已被 SpringerLink 等数据库收录! |
|