Malaria Infection is Lower in Invasive Anoles than Native Anoles in Central Florida, USA

Lizard Dewlap Color and Malaria Infection: Testing the Hamilton-Zuk Hypothesis

The Hamilton-Zuk hypothesis indicates that parasites may have a negative effect on the appearance of sexual traits within an infected individual. Anolis sagrei, or brown anoles, are small invasive lizards common throughout Florida and many other areas where they have been introduced. The colorful dewlaps under the chins of males are used as a signal during territorial contests with other males and as an ornament to attract females. Anoles may be infected by the malaria parasite Plasmodium floridense. In this study, we investigated the relationship of malarial infection with dewlap color and spectral brightness of A. sagrei. We achieved this by capturing male brown anoles, taking blood samples to examine for malarial infection, and recording the color of their dewlaps. We found that the dewlaps of infected Anolis sagrei had duller coloration than the dewlaps of uninfected lizards. These results provide support for the Hamilton-Zuk hypothesis. Our results suggest that infection by P. floridense could potentially influence fitness of the lizards by reducing the expression of their color signals. Additional research on fitness effects of the malaria parasite on anoles is important for fully understanding this phenomenon.

Host Associations of Culex (Melanoconion) atratus (Diptera: Culicidae) and Culex (Melanoconion) pilosus from Florida, USA

Characterizing the host-use patterns of mosquitoes is an essential component of understanding the transmission dynamics of mosquito-vectored pathogens. The host associations of two species of the medically important Culex subgenus Melanoconion, Culex atratus, and Culex pilosus are unknown or unclear, respectively. Both species have wide neotropical distributions. In the United States of America (USA), Culex pilosus occurs throughout the southeastern coastal plain, while Culex atratus is restricted to the southern Florida Peninsula. Using PCR-based blood meal analysis, we investigated the host associations of Culex atratus and Culex pilosus that were collected from Everglades National Park, Florida, USA We identified the host species of 208 Culex atratus and 168 Culex pilosus. Both species were narrowly associated with reptilian host species, particularly native and non-native lizards of the genus Anolis. Sampled Culex atratus exclusively fed on reptilian hosts, with >99% of blood meals derived from Anolis lizards. Culex pilosus fed predominantly from reptiles, but avian and mammalian blood meals were also detected. Of these, 92% of blood meals were derived from Anolis species. For both species, Anolis sagrei, an invasive exotic lizard in Florida, was the most frequently detected host species. These data indicate that Culex atratus and Culex pilosus are specialists of reptilian hosts, particularly Anolis lizards.