06 September 2011

They're Back!

Well just when we started to wonder if our newest invader, Culex coronator, would ever reappear after a protracted absence in Mississippi, it shows up again.  This species has been on a eastward expansion since about 2005 and was one of our more common Culex collected from tires in 2009.  After no state-wide sightings in 2010, we had thought that perhaps Cx. coronator had retreated from our area.  Then late last week we sampled a couple of large tire piles in Waynesboro, MS (about an hour east of the USM campus) and found several to contain larval Cx. coronator.
One of the large tire piles in Waynesboro, MS that contained Culex coronator.  Francis Ezeakacha (Ph.D. student) is seen sampling a tire.  The sunlit tires seen behind him are where we found larval Cx. coronator.
At this point we don't have any firm ideas for why this species has reappeared but my lab threw around some ideas on the long ride back from the sites.  Their disappearance in 2010 could have been the longer and colder winter we experienced in early last year and the individuals we are seeing now may simply be from another wave of recolonization.  It could also be that they were around, but we didn't sample the correct areas.  Regardless we are interested to see them once again.  We currently have a project underway in the lab looking at competition with two established species, Aedes albopictus and Culex quinquefasciatus, that hopefully will give us some insight into how this species may interact with residents.
Another mosquito site we sampled in Waynesboro, MS.  This site did not appear to contain any Cx. coronator, perhaps as many of the tire were in the shade.  Shading is thought to affect presence of some Culex  through adult female oviposition behavior.

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