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I am interested in biodiversity.

I study biodiversity through mosquitoes. The females of most mosquito species require a blood meal, usually taken from a vertebrate host, to produce eggs. For this reason, mosquitoes are closely associated with their vertebrate hosts.

Female mosquitoes take blood from all the major terrestrial vertebrate classes: mammals, birds, reptiles and amphibians. Mosquito species vary in their preferences for certain types of hosts. Some take their blood meals only from warm- or cold-blooded hosts, and some only from particular host classes. There are even mosquito species that feed exclusively from fish (mudskippers). Mosquito-vectored viruses have also been found in wild dolphins and captive orcas, suggesting that they, too, may be fed upon by mosquitoes.

I use molecular methods to study the interactions between mosquitoes and their hosts. When a mosquito takes a blood meal, the host's DNA is present in the mosquito until it is digested. That host DNA can be extracted, Jurassic Park-style, and sequenced. I use DNA barcoding to make taxonomic identifications of host DNA extracted from mosquito blood meals. Most animal cells contain organelles called mitochondria that are involved in cellular respiration. Mitochondria have their own genomes. Because mitochondrial genes are highly conserved across animals, but evolve relatively rapidly, certain regions of mitochondrial genes are species-specific. DNA sequences from those regions can be used as DNA barcodes to taxonomically identify and genetic sample. Mosquito blood meals represent a genetic sample from an unknown animal. Through DNA barcoding, we can determine, with certainty, the identity of a mosquito's host.

Why identify mosquito blood meals?

Mosquito blood meals contain useful information. Mosquitoes are important: As the vectors of disease-causing pathogens, mosquitoes influence human history, behavior, and evolution. The transmission dynamics of mosquito-borne pathogens are rarely simple. Most pathogens can only be transmitted by certain mosquito species, and among mosquito species, there is variation in host preferences. To illustrate this, the eastern equine encephalitis virus is primarily vectored by the mosquito Culiseta melanura. Culiseta melanura feeds almost exclusively on birds, and the virus circulates among wild bird populations. As the prevalence of the virus increases within an ecosystem, it becomes increasingly likely that a secondary, or bridge vector mosquito will move the virus from the mosquito-bird cycle to humans or other mammals. In this case, a bridge vector is a mosquito species that feeds on both birds and mammals. When a bridge vector feeds from an infected bird, it becomes infected itself. After some time, it subsequently feeds on a mammal, transmitting the virus.

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