May 30: Nothing much under the burlap today

No hairstreak larvae under the bands today, but some of the commonly encountered species are reaching their final instars and starting to pupate. I’ve already seen a few chalky yellow tent caterpillar cocoons stuck between the two flaps of burlap on a number of trees and today I found a pupa of another species.

A last instar American Tent caterpillar (Malacosoma americana).

A tent caterpillar cocoon between two burlap flaps.

A chubby molting Ruby Quaker (Orthosia rubescens).

A large, irritated last instar Ilia underwing (Catocala ilia).

Unknown pupa attached to the burlap.

 

Like adult Underwing moths, caterpillars of the genus Catocala flash their startlingly colored parts as a defensive behavior when disturbed by a potential predator (my finger in this case).

May 24: Catocala galore

Having set the bands two weeks earlier this year, I have been able to see a number of species that I only rarely encountered or did not see at all last June. The most striking and impressive of these have been the numerous Ilia Underwings (Catocala ilia) that rest so cryptically on the bark. Last year, I started work at the tail end of this early species’ active period and so only caught 1. This year however, I’ve already seen around 10 very large individuals.

Moths of the genus Catocala are commonly referred to as underwings because of their startling orange hindwing coloration. This flashy patterning is used to scare and confuse potential predators that disturb the otherwise cryptic moths. At rest, they disappear against the bark and leaf little owing to the earthy gray, brown, and black patterns of their forewings. When disturbed by a potential predator, a startling flash of the hindwings sends them running or at least creates enough confusion for a quick getaway.

Interestingly, this startling defensive behavior is not limited to the adult moths. Many underwing caterpillars, Catocala ilia included, are extremely cryptic at rest (see below), but when disturbed they will show off their bright, flashy undersides in a thrashing, writhing display (see video in next post).

Catocala ilia resting on a white oak. Can you spot it?

A classic gray bark-like Catocala ilia.

A distinct lichen form of Catocala ilia.

The characteristic pink venter of Catocala ilia.

Seeing all these Catocala and other species, just shows again how effective this simple collection technique is. If you’re interesting in caterpillars or just a nature lover, then I recommend you set up a burlap band in your yard or wooded area. It is the easiest way to encounter a diversity of caterpillars and other insects, many of which would be impossible to find otherwise.

 

May 16: Tree labeling and first check

Haploa ?clymene on red oak

Kevin and I returned to Great Blue Hill this morning to count and label all the banded trees using small pieces of numbered orange flagging tape. In the process, we checked all the burlap to see if any tenants have yet checked in. These surely are great hiding places because after less than 24 hours of being secured to the oaks trees, the burlap skirts housed a number of caterpillars. These included many Abagrotis sp., a few Haploa ?clymene, one very small Dasychira ?obliquata, and 3 Catocala ilia. The Ilia Underwing caterpillars were a thrill, especially one sizable individual that was a gorgeous pale green lichen mimic. The other two were impressively cryptic against the gray bark they rested on – I can’t imagine I’d find them very easily if they weren’t under the burlap – but the lichen morph was just superb. Aside from that, we also saw a very fresh Juvenal’s Duskywing (Erynnis juvenalis) that allows some very close photography. The total tree count was 96 white oaks and 49 red oaks which is acceptably close to our target number.

A cryptic Ilia underwing (Catocala ilia) resting on a red oak

A handsome green lichen morph Ilia Underwing (Catocala ilia)

A fresh and friendly Juvenal’s Duskywing (Erynnis juvenalis)