June 11: Burlap Removal: Day 1

Urged by today’s successful Oak Hairstreak emergence, I began removing the burlap from all the trees that we’re used in this part of study. I’ve collected 2-3 Oak Hairstreak prepupae thus far which supports the claim that white oak (Quercus alba) is the preferred host in the northern extent of the species’ range. The positive results of the larval sampling efforts this year show how effective burlap banding can be for collecting Oak Hairstreak caterpillars as they descend their hosts to pupate in the leaf litter. Looking back to last year’s results, it seems an early start makes all the difference. Once the gypsy moth, Quaker, and Oak moth caterpillars start to take over (as they are now), the window of opportunity to collect Satyrium caterpillars has closed. This is a good signal to end larval sampling efforts.

In the process of removing the bands, I collected two Satyrium pupae attached to the burlap on two different white oak trees that I hadn’t yet collected hairstreaks from. At this life cycle stage, it is very difficult to differentiate an Oak Hairstreak from a Banded, so I collected these only to get a verifiable identification when they adult emerges. These and any other hairstreaks collected from this point on will only be contained long enough to obtain an identification.

Satyrium ?favonius ontario_3

The first Satyrium pupa I collected today. I found it attached to the burlap on a white oak tree.

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A close-up of Satyrium pupa #1.

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The second Satyrium pupa I collected. Note the cast skin of the final instar larva below this one.

May 30: Successful pupation!

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The first Oak Hairstreak prepupae I collected 2 days ago has successfully pupated on a fresh white oak leaf. I had anticipated that it would prefer dead oak foliage and duff from the base of its host tree, but it apparently was not that picky. The pupa is dark brown mottled with pale spots and appears slightly hirsute. The white spiracles are visible along its sides. You can imagine that this pupa would be perfectly camouflaged among the leaf litter or bark where it would naturally reside. I eagerly anticipate its eclosion.

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.

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A last instar American Tent caterpillar (Malacosoma americana).

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A tent caterpillar cocoon between two burlap flaps.

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A chubby molting Ruby Quaker (Orthosia rubescens).

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

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Unknown pupa attached to the burlap.