Because of last year’s flood and this summer’s steamy weather, many feel there are more mosquitoes in the area. But state experts said the natural disaster has caused more complex changes to this year’s pest population than previously thought.
“Mosquito populations are independent from year to year,” said Lyric Bartholomay, an assistant professor of medical entomology at Iowa State University. “If we look back to the mosquito populations after the flood in ’93, there was no prediction.”
Other experts said the flood may have been somewhat beneficial to insect-loathing humans; mosquito nests may have been washed away, said Patricia Quinlisk, Iowa’s state epidemiologist.
“A lot of mosquitoes enjoy smaller puddles of rain,” she said.
Though the flood had limited effect, the hot and humid weather has played a role in the number of mosquitos in the area. Mosquitoes are attracted to areas that are both warm and wet because of their birthing habits, Bartholomay said.
Mosquitoes lay their eggs in water, she said, and the eggs hatch once they become properly hydrated. The higher the temperature, the faster the larvae grow.
In 2008, officials gave widely reported warnings about a expected increase in the mosquito population. The insects transmit diseases such as West Nile virus from birds to humans. Last year, the virus reportedly caused 44 deaths in the United States — only one of which was in Iowa.
But this year, Quinlisk said, the pests prevalent in the area are “nuisance mosquitoes,” because though they bite, they don’t cause much harm. Furthermore, “only a handful” of the 53 mosquito species in Iowa carry diseases.
While summer heat and humidity can still increase the number of mosquitoes in the area, Quinlisk said the kinds that carry such illnesses as West Nile aren’t usually seen until August or September.
Bartholomay said there is one group that might benefit from the potential rise in mosquito population — fish and aquatic birds will enjoy mosquitoes laying their eggs in and around the river.
“Having more larvae in the water provides a food source,” she said.