Did Cicada Explosion Lead to Boom in Rat Population?
Some Say Rodents Feasted on Insects
By Leef Smith
Washington Post Staff Writer
Thursday, July 29, 2004; Page VA03
And you thought cicadas were just noisy and ugly.
Officials in Alexandria and Arlington said the unusual insects -- which popped up in the Washington area in May and June after 17 years underground -- provided a feast for the area's rodent population, which they say is considerably larger this year and the source of more residential complaints.
While there are no statistics to bolster the cicada-rat theory, officials point to anecdotal evidence culled from exterminators to suggest that the cicada invasion is at least partly responsible for fueling the area's rat population.
"It's logical," said Mike Conner, Alexandria's chief fire marshal, who oversees property maintenance for the city's code enforcement division. "Cicadas are laying on the ground and the rodents are going to eat them. It's going to cause greater proliferation. It's a food source."
Alexandria, a densely populated waterfront city, budgets $168,000 annually for rodent control, which includes measures such as baiting the city's sewers to stem the spread of rats.
Conner said several area exterminators have reported an increase in the rat population over the same time last year.
"They told us the cicadas were excellent feeding material for the rodents," Conner said. "I guess they're loaded with protein."
Rats have an average of three to six litters of six to 12 offspring per year. A female can produce up to 54 offspring a year.
In Arlington County, officials say the number of complaints they have received about rats in the last two months is dramatically larger than last year.
Last July, the county received 60 calls about rats. As of Friday, officials had logged 197 complaints for the month.
"That's four-fold higher," said Aftab Hussain, an environmental health specialist for the county who oversees insect- and rodent-borne diseases. "While there's no scientific data about [the impact] of cicadas, people believe the increase in the rat population is because of them."
University of Maryland entomologist Michael Raupp knows cicadas and isn't convinced they're the culprit.
"There's nothing in the literature that I've seen that links rats eating cicadas," Raupp said. Still, he said "rats are opportunistic eaters. If there were a bazillion cicadas, it could have been a significant food source."
Joseph Goodwin, manager of Alexandria Pest Services, said that based on calls for service, he believes the rat population is out of flux. The culprits, he says, were the cicadas.
© 2004 The Washington Post Company