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Billy West GEO 4300 Lit Review 2 Ishtiaq, F., Clegg, S. M., Phillimore, A. B., Black, R. A., Owens, I. P. F. and Sheldon, B. C. 2010. Biogeographical patterns of blood parasite lineage diversity in avian hosts from southern Melanesian islands. Journal of Biogeography, (2010) 37: 120–132. Ishtiaq and Sheldon are both with the Edward Grey Institute in the University of Oxford’s department of Zoology. Clegg and Black are both with the department of Biology at Imperial College London. Phillimore and Owens too are with the department of Biology at ICL, as well as being with the NERC Centre for Population Biology at ICL. 2) Research Question/Problem How do populations of the parasites Plasmodium and Haemoproteus vary due to their spatial distribution across different islands of varying size in southwest Pacific archipelagos, with specific regard to the population(s) of avian host genus Zosterops? 3) General Background Knowledge for the Study Species richness on islands is strongly correlated with island size, such that larger islands have higher values of species richness; vector-borne parasites, such as Plasmodium and Haemoproteus, that rely on a variety of host species (including insects and birds) might thus be expected to fare better on larger islands with correspondingly larger values of host species richness. Additionally, despite their populations’ being geographically isolated on individual islands in a chain, the intraspecies diversity of such vector-borne parasites may not depend so much on that given that avian hosts can allow for inter-island traffic. 4) Methods The distribution and diversity of the parasite populations was determined by testing enzymes from host Zosterops (Polymerase Chain Reaction, or PCR). Genetic diversity in terms of both nuclear (i.e., species) and mitochondrial DNA was taken into account. Statistical calculations were used to determine host and species’ spatial relationships (linear regressions for species-area and species-distance; Mantel tests for distance-decay). 5) Results of the Study The host bird and mosquito species showed strong species-area relationships, while the parasite Plasmodium's populations showed relatively weak such relationships and Haemoproteus' none at all. Species richness for the parasites was more strongly correlated with avian species richness than with mosquito species richness, and similarity between populations decreased with distance for host species and Plasmodium, but not for Haemoproteus. 6) Weaknesses of the Study While the inadequate sampling for species richness was statistically corrected for, a larger sample would have obviated the need for corrective techniques. Furthermore, the Mantel test is non-parametric and preferentially needs larger samples than do parametric tests in order to be effective (this is unrelated to the sample size for species richness). 7) What we learned new from the study Species-distance relationships for parasites Plasmodium and Haemoproteus are relatively weak, suggesting other factors are more important for species richness on a single island, although distance between islands was generally a factor in terms of genetic diversity.