What's Bugging the Ladybug?

Nov 19, 2009

It probably bugs her but it doesn't kill her.

But why?

An entomologist at the University of Montreal is investigating why parasitic wasps (Dinocampus coccinellae) that lay their eggs on ladybugs (Coccinella maculata) do not kill them.

Often a parasitic insect, such as a tachinid fly, kills its host.

"What is fascinating is that the ladybug is partially paralyzed by the parasite, yet it's eventually released unscathed," says biocontrol specialist and professor Jacques Brodeur. "Once liberated, the ladybug can continue to eat and reproduce as if nothing happened."

It works like this: a larva cocoons between the ladybug's legs. Once the parasite matures, it leaves the host. Brodeur hopes to understand the cycle duration, success rate and the host-parasite relationship.

Talk about hostage-taking.

"Can the ladybug refuse to be used?" he wonders. "We don't know. Our plan is to reproduce a variety of situations in the lab and see which is most favorable to reproduction."

Luck be a lady?

Frankly, we're happy that the aphid-eating ladybug, one of our favorite beneficial insects, doesn't succumb to the wasp.

We need more of them around.


By Kathy Keatley Garvey
Author - Communications specialist

Attached Images:

LADYBUG crawls on a leaf at the UC Berkeley Botanical Garden. (Photo by Kathy Keatley Garvey)

Ladybug

CLOSE-UP of a ladybug in Vacaville, Calif., eating aphids. (Photo by Kathy Keatley Garvey)

Close-up

LADYBUG searching for more aphids. (Photo by Kathy Keatley Garvey)

Searching for More Aphids