Albert Lea Tribune, MN
09-08-07
Prof: Trivittatus skeeters not so rare
By Tim Engstrom, managing editor
It turns out that pesky strain of mosquitoes has been around in larger numbers
between now and 1975 than first reported, and this little bug is quite a vicious
little bug.
Locals had commented on how pesky the mosquito population has been the past
week. That made the Tribune curious about just how pesky was this species,
which scientists call Aedes trivittatus. We also were curious, even skeptical,
about the claim the species hadn’t been around in large numbers since 1975.
The newspaper decided to contact a professor of entomology at Iowa State
University, which has a renowned entomology department.
I sent questions via e-mail to Lyric Bartholomay. Here are my questions and
her answers. Bartholomay is an assistant professor of medical entomology.
Q. Is the species Aedes trivittatus more determined than other mosquitoes?
A. Aedes trivittatus prefers to feed on humans and has vicious feeding
tendencies. Aedes trivittatus will feed during all hours of the day, but tend to
prefer dusk-evening hours.
Q. Does that species generate greater complaints than others?
A. Aedes trivittatus and Aedes vexans are the floodwater mosquitoes that tend to
generate the highest number of complaints in Iowa as far as nuisance
mosquitoes are concerned. Both species lay their eggs in locations that tend to
be flooded with the onset of heavy rains, hence the term floodwater mosquito. If
an area has not been flooded in a number of years, many eggs may hatch,
resulting in increased numbers of adult mosquitoes. It is not at all uncommon to
see very high populations of Aedes trivittatus along wooded streams in Iowa,
especially following heavy rains.
Q. We understand from the company Mosquito Control of Iowa that the species
is back in the largest numbers seen since 1975. So I looked at your department’s
mosquito Web site (I provided her a link) and saw the Aedes trivittatus graph
show a spike in 1975.
A. The graphs found at iowa-mosquito.net do suggest that the highest numbers
of this species of mosquito were seen in 1975, but be clear that these numbers
were generated at a single site in that one year, so do not reflect what we see
across the whole state. High numbers of Aedes trivittatus are not at all
uncommon in Iowa, especially following periods of heavy rain. Based on the data
from our trapping efforts, these mosquitoes tend to be most abundant in midJuly, so this perhaps is later in the season than usual to be seeing large numbers
of Aedes trivittatus, but, again, the timing of this mosquito problem makes good
biological sense in terms of the rain we experienced in August.