In this species, the larvae emerge from the carcass of their mother in her pupal case. These newborn larva emerge from the bottom of the hanging case and drop down on a strand of silk. The wind will then blow them to a nearby plant where they can build their own cases made of silk, fecal material, and plant bits. Adult males transform into moths in about four weeks and immediately seek out females for mating. The females never leave the cocoon, but wait for a male to stick its abdomen through the opening at the end of her case so they can mate. Females do not have eyes, legs, wings, or antennae...and, they can't eat. After her death, her offspring hatch and then pass through her body and leave the case."/>
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Evergreen Bagworm Case

Thyridopteryx ephemeraeformis

Description:

Bagworms are not really worms, but are caterpillars - they are the immature stage of a moth. They're called "bagworms" because they construct bags/cases that are covered with pieces of twigs and/or leaves. This case had a big hole in the top, and I'm not sure if it was made by a caterpillar/moth or parasitoid.

In this species, the larvae emerge from the carcass of their mother in her pupal case. These newborn larva emerge from the bottom of the hanging case and drop down on a strand of silk. The wind will then blow them to a nearby plant where they can build their own cases made of silk, fecal material, and plant bits. Adult males transform into moths in about four weeks and immediately seek out females for mating. The females never leave the cocoon, but wait for a male to stick its abdomen through the opening at the end of her case so they can mate. Females do not have eyes, legs, wings, or antennae...and, they can't eat. After her death, her offspring hatch and then pass through her body and leave the case.

Habitat:

Spotted on arborvitae

Notes:

Arborvitae and red cedar are the favored hosts of this species of bagworm.

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3 Comments

Christine Y.
Christine Y. 2 years ago

Thanks! @Tukup - it's totally weird! I have been seeing lots of these cases in the past year or so. I counted over a hundred last autumn!

Tukup
Tukup 2 years ago

The foto is interesting but the write-up is excellent. How weird a life cycle is that? Thanks so much for sharing Christine.

Roy Arun
Roy Arun 2 years ago

Stunning.....👍👍

Christine Y.
Spotted by
Christine Y.

Connecticut, USA

Spotted on Nov 19, 2018
Submitted on Apr 4, 2019

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