A Baylor University study has found female mosquitoes prefer to lay their eggs on or close to water in which other mosquito larvae have developed, suggesting that female mosquitoes can somehow detect where other larvae have been successful.
The study, conducted by Dr. Richard Duhrkopf, associate professor of biology at Baylor, also shows female mosquitoes prefer these spots over other areas at a nearly two-to-one margin and lay up to three times more eggs there.
The results were presented at the South Central Regional Mosquito Control Conference.
"I think it is kind of an insurance process," said Duhrkopf, who has been studying mosquitoes for more than 30 years. "If other mosquito larvae have succeeded in developing in certain water, it must have adequate nutrients, and there is a good chance new larvae will be successful in that water as well. It's really interesting because it suggests that there are metabolic by-products of larvae that the female mosquitoes can detect."
Duhrkopf and his team created five separate water-based solutions where the mosquitoes could choose to lay their eggs. The solutions contained either deionized water; alfalfa hay infused water; rabbit chow infused water; water with a commercialized attractant; and water taken from a household back yard that had previous mosquito larvae in it. The Baylor researchers then placed the solutions at nearly 250 different areas around a natural 50-acre site. Collections were made in 24 hour increments.
The results show:
Overall, 58 percent of the solutions had mosquito larvae in them and there were a total of 3,718 eggs.
There were large differences in the number of females attracted to the solutions and the number of eggs laid in the solutions, differing by the composition of the water.
The "back yard" water solutions significantly attracted more females and more eggs per positive trap. The back yard water solutions had 1,808 eggs on them versus the next highest one, deionized water, which had only 799.
The commercial solution attracted approximately the same number of females and had approximately the same number of eggs per trap as traps with solutions of rabbit chow or deionized water.
Solutions with an alfalfa hay infusion attracted significantly fewer females and contained fewer eggs.