Document Type

Dissertation

Degree

Doctor of Philosophy

Major

Biology, Ecology

Date of Defense

4-16-2018

Graduate Advisor

Patricia G Parker

Committee

Robert Marquis

Nathan Muchhala

Steven Juliano

Abstract

Mosquitoes remain important vectors in transmitting wildlife diseases. This dissertation aims to understand the role that mosquitoes play in transmitting wildlife diseases such as avian malaria, a protozoan parasite belonging to the genus Plasmodium. Using data from wild-caught mosquitoes captured in multiple years and across multiple islands on the Galapagos Archipelago, we describe distributional patterns of mosquitoes, their range limits and assess whether there exists a disease-free refuge as occurs in Hawaii. We show that altitudinal ranges for disease transmission of avian malaria may not be bounded by a stable disease-free refuge, since mosquitoes are found at all elevations, and the highest peaks are significantly lower in Galapagos than in Hawaii. Secondly, we investigate the influence of ecological factors on the distribution and abundance of mosquitoes on the inhabited island of Isla Santa Cruz. We show that both Aedes taeniorhynchus and Culex quinquefasciatus, two of the three mosquito species found in Galapagos, decline with elevation. We also show the influence of statistically significant factors of elevation, temperature, and humidity on mosquitoes in Galapagos. This chapter discusses the ecological requirements of the avian malarial parasite and how this may influence disease dynamics in the Galapagos; sampling sites at all elevations were within the optimal temperature range for both mosquito and parasite development. Thirdly, using data from wild-caught mosquitoes from Santa Cruz, we discuss the feeding range of both A. taeniorhynchus and C. quinquefasciatus. This chapter takes a molecular approach in screening mosquito bloodmeals using vertebrate universal primers. Fourthly, we use a combination of field captured mosquitoes, molecular screening, and microscopy in identifying Plasmodium parasites and understanding their competence in the disease dynamics of avian malaria in Galapagos. Collectively, these results aim to guide conservation efforts towards managing disease-transmitting mosquito vectors in Galapagos.

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