You are not currently logged in.
Access JSTOR through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Geographic Variation and Evolution of Immunosuppressive Genes in a Drosophila Parasitoid
Stephane Dupas and Marco Boscaro
Vol. 22, No. 3 (Jun., 1999), pp. 284-291
Stable URL: http://www.jstor.org/stable/3683038
Page Count: 8
You can always find the topics here!Topics: Parasite hosts, Parasitoids, Species, Drosophila, Evolution, Parasites, Boxes, Genetics, Host range, Insect larvae
Were these topics helpful?See something inaccurate? Let us know!
Select the topics that are inaccurate.
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
Parasitoids that must kill the host to complete their development are expected to evolve towards increased virulence. In some conditions however Leptopilina boulardi loses its ability to counteract the host immune reaction. This trait is determined by major genes. For each host species there is a specific gene for immune suppression by the parasite. Here the geographic variations of the immunosuppressive gene frequencies are investigated in relation to the distribution of the host species. The necessity to deal with host immunity is a major constraint on the host range of L. boulardi. Against Drosophila simulans and D. yakuba, the presence of the immunosuppressive allele is correlated with the presence of the host species in the locality. Against D. melanogaster, the data suggest that this gene is counterselected when the parasite is exposed to numerous host species. This counterselection is explained by the existence of a cost of immunosuppressive genes. Against D. yakuba, this cost was evaluated in population cages as a selective coefficient of s = -0.20. The cost differs between the genes. Against D. melanogaster, it was not significant in population cage conditions. The parasitoid invests more in the suppression of the D. yakuba reaction than that of D. melanogaster. This variation of the investment in immunosuppression is discussed within the framework of the adaptive budget theory.
Ecography © 1999 Nordic Society Oikos