Behavioral Ecology Advance Access published online on June 4, 2008
Behavioral Ecology, doi:10.1093/beheco/arn058
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Sperm investment in relation to weapon size in a male trimorphic insect?
a Department of Biology, University of Toronto at Mississauga, Mississauga, Ontario L5L 1C6, Canada b School of Botany and Zoology, Australian National University, Canberra, Australian Capital Territory 0200, Australia
Address correspondence to C.D. Kelly, who is now at Department of Psychology, Dalhousie University, Halifax, Nova Scotia B3H 4J1, Canada. E-mail: clintkelly{at}dal.ca.
 |
Abstract |
|---|
In the harem polygynous Wellington tree weta (Hemideina crassidens), early maturation at the eighth instar by males is associated with smaller mandibular weaponry. Because these males, compared with larger males (i.e., matured at 10th instar), are less successful at holding harems, they appear to have decreased mating success. Therefore, smaller males may acquire mates using tactics different than those of males with larger weaponry. A source of empirical support for this hypothesis is to show that smaller males offset their mating disadvantage by investing more in spermatogenesis to achieve fertilization success. Contrary to expectation, relative investment in testes (controlling for body size) is similar for smaller and larger males. I suggest that this lack of difference in testes size may be due to both morphs experiencing similar risks of sperm competition on Maud Island. Despite having testes similar in size to larger males, smaller males produce significantly larger ejaculates than males with bigger weaponry. This difference in ejaculate size may stem from larger males investing submaximally in current ejaculates in anticipation of their higher future mating success.
Key words: accessory gland size, allometry, ejaculate size, sexual selection, sperm competition, sperm number, strategic ejaculation, testis size.
Received 1 August 2007; revised 14 April 2008; accepted 28 April 2008.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  J. M. Rowland and D. J. Emlen Two Thresholds, Three Male Forms Result in Facultative Male Trimorphism in Beetles Science, February 6, 2009; 323(5915): 773 - 776. [Abstract] [Full Text] [PDF]
|
|