Competition for hosts by Asobara pleuralis


Braconid parasitoids of Drosophila lay their eggs in the larvae of Drosophila. In many species of parasitoids, females arriving on the same host patch search for hosts without any sign of interference between them and may lay eggs in hosts already parasitized by a competing female.  In such (superparasitized) hosts, competition occurs between first instar parasitoid larvae. The larvae engage in a physical fight. The winner kills the loser by piercing it with its mandibles.
However, sometimes a different competitive strategy is found, e.g. patch defense by a searching female, was observed in the parasitoid Asobara citri. The first female A.citri to arrive on a patch will attack later arriving females and chase them away and patrol the patch edge to prevent a second intrusion. In the past we have developed theories on the adaptive meaning of these two competitive modes, and predicted that patch defence can only evolve when travel times between patches are short. The latter is commonly found in tropical regions where fermenting fruits, the breeding site of Drosophila, can be locally abundant.
We have recently started to study Asobara pleuralis, a species from Sulawesi in Indonesia, and would like to know whether it competes by superparasitism, by patch defence, or by any other means.
The practical work in this project consists of behavioural experiments, in which female A.pleuralis will be confronted with intruding competitors. Fitness, expressed as number of offspring produced per unit of time will be measured in the presence and in the absence of intruders. Likewise we will measure intruder fitness and compare to the alternative strategy of traveling to a new patch and produce offspring there.

This project can be done as BSc stage (4 months), or be extended to a MSc research project.


Supervision: Majeed Askari & Jacques van Alphen


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This page contains a single entry by administrator published on April 21, 2008 8:24 PM.

Biodiversity of nocturnal Lepidoptera in the dunes was the previous entry in this blog.

The effect of different resources of energy allocation on longevity and fecundity of Asobara species is the next entry in this blog.

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