Patch Defence in the Parasitoid Wasp Trissolcus Basalis: When to Begin Fighting?
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Abstract
Foragers that exploit defendable patches are faced with a trade-off, between exploiting the patch, and defending it against competitors. In insect parasitoids, this trade-off is compounded by the fact that the host resources are not consumed, but remain in the environment after being exploited and therefore are still vulnerable to attack by competitors. The parasitoid wasp Trissolcus basalis (Hymenoptera: Scelionidae) exploits the egg masses of pentatomid bugs, and females are able to monopolise and defend patches of hosts. However, females usually do not begin fighting immediately, but co-exploit the patch without aggression for some time. This paper uses survival analysis to examine their decision-making rules with respect to when to begin defending a patch. The decision to begin fighting was influenced by the size of the patch, the number of offspring previously invested in the patch, the encounter rate with con specifics, and the encounter rate with unparasitised hosts. These factors reflect a balance between defending the resource and defending offspring, and highlight the increasing value of a patch to a female as she invests more offspring in it.
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| All Time | Past 365 days | Past 30 Days | |
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Patch Defence in the Parasitoid Wasp Trissolcus Basalis: When to Begin Fighting?
In: BehaviourSearch for other papers by Scott Field in
Current site
Google Scholar
PubMed
Search for other papers by Gregory Calbert in
Current site
Google Scholar
PubMed
Abstract
Foragers that exploit defendable patches are faced with a trade-off, between exploiting the patch, and defending it against competitors. In insect parasitoids, this trade-off is compounded by the fact that the host resources are not consumed, but remain in the environment after being exploited and therefore are still vulnerable to attack by competitors. The parasitoid wasp Trissolcus basalis (Hymenoptera: Scelionidae) exploits the egg masses of pentatomid bugs, and females are able to monopolise and defend patches of hosts. However, females usually do not begin fighting immediately, but co-exploit the patch without aggression for some time. This paper uses survival analysis to examine their decision-making rules with respect to when to begin defending a patch. The decision to begin fighting was influenced by the size of the patch, the number of offspring previously invested in the patch, the encounter rate with con specifics, and the encounter rate with unparasitised hosts. These factors reflect a balance between defending the resource and defending offspring, and highlight the increasing value of a patch to a female as she invests more offspring in it.
| All Time | Past 365 days | Past 30 Days | |
|---|---|---|---|
| Abstract Views | 496 | 38 | 12 |
| Full Text Views | 139 | 0 | 0 |
| PDF Views & Downloads | 52 | 0 | 0 |
