May 27: Oak Hairstreak at last!

Oak Hairstreak prepupa (Satyrium favonius ontario)

First and foremost, ladies and gentlemen….the oak hairstreak!!!! The fruit of my burlap-flipping labor presented itself today in the form of a stout green prepupa attached to the burlap flap on a mature white oak tree near the stone lookout tower. To differentiate from other hairstreak larvae I have encountered in the area, this species has a dark dorsal heartline and is covered with small white speckles that appear to be setal bases though the only obvious setae are the fringe setae around the outside edges of its body. Finding this caterpillar both verifies white oak (Quercus alba) as the host plant for this hairstreak and demonstrates the efficacy of burlap band larval sampling. Just as we had theorized, we captured a prepupal caterpillar that was heading to the duff at the base of the tree to pupate. I could easily tell it was prepupal because it was developing a rosy tinge to its posterior edge. I carefully collected this specimen from the burlap and put it in a container with proper substrate to pupate in. Through prior research on the Oak Hairstreak, I am quite confident this is the larva, but it must be reared to adulthood to make a proper identification. When it emerges, this single butterfly will be saved as a voucher specimen for this project and used to do any DNA work. I am incomprehensibly excited and relieved to have found this caterpillar, but also surprised at how far it was from the slope.

In checking all the other burlap skirts, I found one new species, Lytrosis unitaria, a large geometrid. On another band, I found a large cluster of Forest Tent caterpillars in a group molt. They formed a very conspicuous, fuzzy lump on the tree. As I walked through the woods, I noticed a nigh number of Dasychira obliquata caterpillars as well as green sawflies (Craterocercus sp. or Pristiphora sp.) eating oak. I don’t seem to remember running into so many of these last year.

Lytrosis unitaria under burlap.

 

Molting cluster of Forest tent caterpillars (Malacosoma disstria).

Streaked Tussock Moth (Dasychira obliquata)

Sawfly (Craterocercus sp. or Pristiphora sp.) eating oak

The other species that has reached devastating numbers as we realized during the night visit is the winter moth (Operophthera brumata). Below is the type of damage that these pesky and voracious little caterpillars can do.

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)

 

June 5: Lycaenid under the burlap

Today I did another full check of the burlap bands and made two new additions to the species list. First was this handsome, gray, mohawked lymantriid that I believe is Dasychira obliquata. I actually saw a very early instar Dasychira during my first trip to Blue Hills when the oak trees were just leafing out. It was being investigated by a curious ant.

Streaked Tussock Moth larva (Dasychira obliquata)

early instar Dasychira being investigated by ant

The second new species was a great surprise to find. I lifted up a flap of burlap and a bright green little lycaenid was looking back at me. After seeing so many gypsy moths caterpillars, this little slug-like larva seemed electric green and the find merited a rush of excitement. Sadly, yet expectedly, it was not an Oak Hairstreak and we suspect it is a White-M Hairstreak (Parrhasius m-album). It is in our rearing room now, stay tuned for emergence!

White M Hairstreak larva (Parrhasius m-album) under burlap

White M close up