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Impact of competition on sex allocation by Trichogramma
Article first published online: 24 MAR 2004
DOI: 10.1111/j.0013-8703.2004.00146.x
Additional Information
How to Cite
Martel, V. and Boivin, G. (2004), Impact of competition on sex allocation by Trichogramma. Entomologia Experimentalis et Applicata, 111: 29–35. doi: 10.1111/j.0013-8703.2004.00146.x
Publication History
- Issue published online: 24 MAR 2004
- Article first published online: 24 MAR 2004
- Accepted: 22 December 2003
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Keywords:
- local mate competition;
- interspecific competition;
- sex allocation;
- egg parasitoid;
- Trichogramma;
- Hymenoptera;
- Trichogrammatidae
Abstract
Hymenopteran parasitoids change their sex ratio following different factors. One of these factors is the exploitation of a host patch by several females. The Local Mate Competition (LMC) model (Hamilton, 1967) states that when there are many foundresses on a patch, they should lay a higher sex ratio. The impact of both intra- and interspecific competition on sex allocation was measured in two egg parasitoids, Trichogramma minutum Riley and T. pintoi Voegele (Hymenoptera: Trichogrammatidae), by comparing the sex ratio deposited by females exploiting host patches alone and in groups. Results showed that the sex ratio deposited by both species was higher when in groups, as predicted by the LMC model. When the sex ratio produced was compared between females either alone or in interspecific groups, T. minutum females deposited the same sex ratio, while T. pintoi produced more sons when in interspecific groups than when alone. These results are discussed following their natural habitat and their discrimination abilities.