- Author: Kathy Keatley Garvey
It's a curious-looking insect, the tachinid fly.
The first thing you notice are the thick, dark bristles covering its abdomen. By human standards, this insect, about the size of a house fly, is not pretty. No way, no how.
But there it was, resting on a purple-leaf sand cherry (genus Cistus, rockrose family Cistaceae) in our garden.
As an adult, the tachinid fly nectars on flowers. In its larval stage, it's an internal parasite. The female is known for laying her eggs in Lepidoptera caterpillars and in the larvae of other insects. Hostest with the mostest?
Lepidoptera is a order that includes butterflies and moths, and if you study them, you're a lepidopterist.
California has more than 400 species of tachinid flies. There's even one species called the "Caterpillar Destroyer" (Lespesia archippivora). It targets the caterpillars of those graceful Monarch butterflies we see flitting through the flowers.
Most folks will look at a tachinid fly and mutter "Yecch! That sure is a weird-looking fly."
By human standards.