The growth of Hoverflies

A hoverfly of the Meliscaeva genus   Hoverflies don’t sting, but to repel predators they sometimes pretend to. And to aid in the deception, they look remarkably like wasps and bees. Now it turns out that bigger hoverflies seem to be better mimics of stinging insects than smaller ones — perhaps the larger flies are more attractive to predators. Evolutionarily, they had more to gain by honing their mimicry skills.
The researchers, who report their findings in the current issue of Nature, looked at as many features as they could measure in 31 species of hoverflies — like antenna length, abdomen length and abdomen width. They combined these data with ratings on the quality of mimicry.
“Mimicry is a really close resemblance to its model,” said Tom Sherratt, an evolutionary ecologist at Carleton University in Ottawa and one of the study’s authors. “The question is, why doesn’t an even closer resemblance evolve?
“Large species represent a much more substantial meal to a would-be predator,” he continued. “There’s more incentive for the predator to give them a good checking out.”
Smaller hoverflies, on the other hand, are less attractive and may receive a less thorough look.
“When you’re small, even a vague resemblance might be enough,” Dr. Sherratt said.
The scientists think they may be able to apply similar methods to study mimicry in other animals. Next up: large caterpillars with eyespots that help them mimic snakes.