A parasitoid maggot or larva emerges from your caterpillar or chrysalis. What is it? How can you tell?
Trogus pennator wasp
Swallowtail butterfly parasitoid
Emerges as an adult from a chrysalis
Here are a few tips about the parasitoids you’re most apt to see.
Tachinid fly maggots/larvae (some species leave via a mucus strand that dries into a white string)
Braconid wasp larvae (which then make their cocoons on or near the caterpillar)
Tachinid fly larvae
Trogus wasp larvae (normally from swallowtail butterflies)
Chalcid wasp adults
Trogus wasp emerges as an adult
Often parasitizes swallowtails
Braconid wasp larvae
Emerges from caterpillars
Make cocoons on or near caterpillar
Chalcid wasps emerge from chrysalis
May be black, yellow, or another color
Color depends on wasp species
Yellow chalcid wasp
emerged from sulphur chrysalises
If a chrysalis breaks open, you may see chalcid larvae in it. Chalcid larvae do not emerge from a chrysalis. Only adults emerge from a chrysalis. Click here to see chalcid wasps leaving a Monarch butterfly chrysalis.
Swallowtail chrysalis split open
Filled with chalcid wasp larvae
Male chalcid wasp leaving chrysalis of Black Swallowtail butterfly
Chalcid wasps lay eggs in soft chrysalises
Ichneuman wasps emerge from chrysalises
Ichneuman wasp hole left in a chrysalises
Ichneuman wasp larva
left caterpillar skin as if molting
and made a small cocoon
Ichneuman wasp cocoon
Skin of caterpillar right of cocoon
Tachinid fly maggot emerged from a J’ing caterpillar
Some emerge from dead caterpillars
without leaving a string.
Click on this sentence to see a maggot moving after leaving a dead moth caterpillar.
Tachinid fly maggots/larvae can emerge from chrysalis as well as a caterpillar
Dead dagger moth caterpillar
with several tachinid fly
maggots yet to emerge
There are many parasitoid/parasite species other than these few listed.