About the system

Aedes albopictus as a model system.

 

Aedes albopictus is considered among the most invasive animal species on Earth and is also of considerable medical importance as a vector of Dengue fever, Chikungunya, and a number of other arthropod- borne viruses. It invaded the United States in 1985, and has since spread to the southern tip of the Florida peninsula, and as far north as New Jersey, Ohio, and Illinois (a range of approximately 15 degrees of latitude). We are studying the invasion and range expansion of Ae. albopictus as a natural experiment in order to address questions about the evolution and molecular and physiological basis of important life-history traits.

 

Photoperiodic diapause.

 

Photoperiodic diapause refers to the ability of insects to measure day length (photoperiod) as a cue for initiating seasonally appropriate patterns of dormancy. Photoperiodic diapause is a fundamental adaptation to survival during the unfavorable conditions of winter in a wide variety of temperate insects. Despite the well established ecological significance of photoperiodic diapause, the molecular basis of this critical adaptation remains largely unresolved. We have recently completed a study demonstrating rapid evolution of the timing of photoperiodic diapause during the range expansion of Ae. albopictus in North America. We are also investigating the molecular and phsyiological basis of the photoperiodic diapuase response WITHIN populations. In Ae. albopictus, the adult female is the photosensitive stage, and under the influence of short day lengths female lay diapause eggs in which development arrest (diapause) occurs in the "pharate" (hidden) larva inside the chorion of the egg. Much of our work in this area is being done in collaboration with David Denliger and Julie Reynolds at the Ohio State University.

 

The molecular physiology of photoperiod diapause.

 

We are using high-throughput sequencing approaches (454 and Illumina) to identify transcriptional elements of the diapause response. We have recently completed analyses of transcriptome sequencing of oocytes and are in the processes of sequencing diapause and non-diapause transcriptomes at several additional developmental stages. The oocyte sequencing results identified a large number of transcripts that are upregulated under both diapause and non-diapause conditions. We are currently following up on a number of these transcripts that we think may have particularly interesting diapause-related functions.