Despite the importance of host range for safe and effective biological control, little is known about the host specificity of parasitoid populations. An example of this is the aphidiine parasitoid, Aphidius colemani. As a species, A. colemani is reported to attack nearly 40 species of aphids. However, individual populations may have more restricted host ranges. Here we compare the ability of three populations of A. colemani in terms of their ability to accept and successfully develop in the following four aphid species: Aphis gossypii (cotton aphid), Rhopalosiphum padi (bird cherry-oat aphid), Myzus persicae (green peach aphid), Schizaphis graminum (greenbug). One population was field-collected from R. padi in Israel and the other two were insectary-derived populations (one from Israel and the other from England) from A. gossypii. The field-collected Israeli population was reproductively incompatible with the other two populations, suggesting that it is a sibling species. The two insectary populations were fully reproductively compatible. Host suitability differed between sibling species as well as between populations of the same species. The field-collected population produced significantly more offspring on R. padi than either of the insectary populations. The Israeli insectary population produced more offspring on A. gossypii than the English insectary population, whereas the English insectary population produced more offspring on S. graminum and R. padi than the Israeli insectary population. Different populations of the same parasitoid species are not equivalent in terms of their host use, suggesting that they differ in their effectiveness as biocontrol agents as well as their potential for non-target impacts.
Species 1: Hymenoptera Braconidae Aphidius colemani
Species 2: Homoptera Aphidae Rhopalosiphum padi (bird cherry-oat aphid)
Species 3: Homoptera Aphidae Aphis gossypii (cotton aphid)
Keywords: biological control, host specificity
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA