In the field in Brazil last month, a couple of fantastic colleagues found a new type of life history for a Megaselia (phorid fly species). Dayse Marques and Steve Marshall were walking on a trail and came across a group of caterpillars of the genus Euglyphis (Lasiocampidae).

Dayse noticed a small phorid fly on the back of one caterpillar, and Steve captured the apparent oviposition beautifully. They also were able to collect the fly, which appears to be an undescribed species (no big surprise there!).

Phorids are known to attack damaged, dying caterpillars, but oviposition on an apparently healthy living host is new. I hope that the caterpillar-rearers of the world will keep their eyes open to the possibility of primary phorid parasitism, and not dismiss them immediately as secondary scavenger attack by Megaselia scalaris or some other vulture-like species.

I thank Steve and Dayse for sharing their expertise, and Dan Janzen for his caterpillar ID.