Sperm investment in relation to weapon size in a male trimorphic insect?
Open Access
- 4 June 2008
- journal article
- Published by Oxford University Press (OUP) in Behavioral Ecology
- Vol. 19 (5), 1018-1024
- https://doi.org/10.1093/beheco/arn058
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.Keywords
This publication has 52 references indexed in Scilit:
- Sperm competition games: optimal sperm allocation in response to the size of competing ejaculatesProceedings. Biological sciences, 2006
- SOCIAL STATUS AND AVAILABILITY OF FEMALES DETERMINE PATTERNS OF SPERM ALLOCATION IN THE FOWLEvolution, 2006
- Pitfalls in experiments testing predictions from sperm competition theoryJournal of Evolutionary Biology, 2005
- Male sperm expenditure under sperm competition risk and intensity in quacking frogsBehavioral Ecology, 2004
- The evolution of alternative strategies and tacticsAdvances in the Study of Behavior, 2001
- Sexual selection and secondary sexual characters of wetas and king crickets.Published by CABI Publishing ,2001
- Mating behaviour.Published by CABI Publishing ,2001
- Sperm Competition Games: A Comparison of Loaded Raffle Models and their Biological ImplicationsJournal of Theoretical Biology, 2000
- Allocation to Mate Guarding or Increased Sperm Production in a Mediterranean WrasseThe American Naturalist, 2000
- Alternative reproductive tactics and male-dimorphism in the horned beetle Onthophagus acuminatus (Coleoptera: Scarabaeidae)Behavioral Ecology and Sociobiology, 1997