Many silkmoth caterpillars spin thick silken cocoons that they attach to branches or plant stems. When it’s time for raspa silkmoths like this one to transition into their adult form, however, they metamorphose down in the soil. Underground, they create chambers by tying pieces of soil and humus together with silk.

Living in isolated populations in Arizona, West Texas and in Mexico, these moths face threats including from climate change. In the hot, arid areas where they live, there is usually very little precipitation. But in July, August and early September, there are reliable rainstorms. It’s during this so-called “monsoon” season that these moths emerge as adults. If that weather pattern is shifted dramatically by ongoing drought or otherwise becomes erratic, it could imperil these and other southwestern moths and butterflies.

Raspa silkmoth
Sphingicampa raspa
About 2.6–3.25 inches (6.6–8.2 cm)
Ecological Role
AMNH Specimen Number
AMNH_IZC 00329554