06 July 2011

Our newest invader arrives!

A couple years ago we first encountered Culex coronator in tires at a large salvage yard just outside of Hattiesburg, MS.  During that season Cx. coronator was the 3rd most common Culex we found in tires.  This species, part of a complex of Culex coronator (composed of about 6 species) that is distributed throughout South and Central America, was found over the last half of the 20th century in far southern Texas, New Mexico, and Arizona.  In the early 2000s it began an eastward expansion with appearances in Arkansas and Louisiana, followed by even larger movement into the deep south (AL, MS, GA, FL) and then into some of the southern Atlantic states (NC, SC).  
Bruce Harrison, who works with for the State of North Carolina, has been tracking this species for some time and has made a great map showing the movement of Cx. coronator
 The perplexing thing is that we don't know what has led to the movement we have seen.  Some have suggested that the expansion has been aided by hurricanes or perhaps changes in climate patterns (a.k.a. global warming).  My own feeling is that tires may play a role, as other species have used tires to expand their range.   
Thanks to Dr. Barry Alto (at the Florida Medical Entomology Lab), we are now establishing a colony of this species in the lab.  Why not use local Cx. coronator?  Well it turns out that its not just it's appearance that is hard to explain.  Since the end of last year this species has seemed to make a retreat in several places, including here in MS.  We often coordinate with the folks at the state Health Department who are in charge of adult mosquito sampling, and they have not seem Cx. coronator for some time.  So where did they go?  Only time will tell if they are still around, but as tires and other containers are likely to be a fringe habitat, it may be that we will encounter them in ditches or seeps.  In the mean time we are going to be exploring some of their ecology, especially any interactions with native and other invasive species (like Aedes albopictus, on the right shown above).  


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