Look closerInsects
Cicada shells on tree trunks: what the empty brown husks are
When: July to September
The brown husk on a Sudbury tree trunk is the outgrown skin of a dog-day cicada nymph that climbed up after years underground and split out the back as a winged adult.
Why this time of year
Massachusetts' annual cicadas emerge all through the hot weeks of late summer, each one leaving a shell where it climbed, while the adults drone from the treetops on warm afternoons.
How to notice it
- Check the lower trunks of mature trees, plus fence posts and walls near them.
- Look at how the empty claws still grip the bark.
- Leave any shell alone if the insect is still inside or still pulling free.
Try this with kids: Can you find the split down the back where the adult crawled out?
the shell is a molt, the empty outer skin an insect leaves behind when it outgrows it
Sources
- massaudubon.organnual cicadas in MA sing on late summer days; nymph digs to the surface at night, crawls up a tree trunk, anchors with its claws, and splits out of its exoskeleton; molted exoskeletons left on trees
- extension.illinois.edudog-day cicadas appear every summer, usually July through September; nymphs climb a tree or other upright object and shed the exoskeleton
In the guide for July, August, September