Sunday, April 15, 2012

Glorious Silkmoths, Sapsucker Returns and Long Lasting Flowers

An adult male Cecropia Moth emerges early

Twin Promethea Moth cocoons on a Cherry sapling
Over the years we’ve had several of the large North American silkmoths show up at Spring Farm and around the Nature Preserve. Most recently we’ve been coming across a few of the cocoons of these enigmatic species. On one Black Cherry sapling, 4 cocoons of the Promethea Moth were located. While still in its caterpillar stage, the Promethea Moth folds over a cherry leaf and spins silk around it, until both the caterpillar and the leaf is completely shrouded in silk. Before the cocoon is made, the leaf’s attachment to its branch is strengthened by reinforcing strands of silk. This precaution is necessary if the cocoon is to remain attached to the tree through the fall and winter months. During the first prolonged warm spell –probably in mid to late spring, the adult Promethea Moth will emerge from its cocoon and begin its search for a mate.
The incredible Cecropia Moth
The Cecropia's "bag" cocoon
Note the huge antennae on this male Polyphemus Moth

A week ago, a neighbor (and co-worker) had an adult Cecropia Moth fly into her house. Evidently the moth had emerged from its cocoon far too early in the season; this was due to a few unseasonably warm weeks in March. The moth was released the following afternoon during the warmest part of the day. Still, it was pretty cool outside, so he needed to bring his body temperature up. He did this by quivering his wings. After about 10 minutes he was warm enough to fly, and he very competently fluttered off into the woods. He landed on a high branch –but remained there for only a few minutes before coming back our way and making a farewell pass right over our heads. The Cecropia is a really big moth –as big as our largest butterflies. The male has large feathered antennae that they use to locate females; he can detect a female’s pheromones from up to a mile away. Mating will pretty much be his only goal, since these moths have no mouth parts and do not feed.
The Male Luna Moth
The Cecropia Moth’s cocoon looks a bit like a little tan bag hanging –typically, from a low branch of a deciduous tree or shrub. Inside the silken bag is the pupa which will transform into the adult Moth. Recently, I found 2 of these cocoon “bags” in one of our meadows.

A male Sapsucker checking his line of sap holes

The Yellow-bellied Sapsucker returned from the south early last week, and now the old woods resound with this woodpecker’s characteristic drumming. Their drumming pattern is uneven and it sounds a bit like the bird is communicating in Morse Code. This species is among the very few wild animals that leave evidence of its work which can be visible more than a century later. The sap holes that they drill through the bark of trees eventually heal over, but they remain as visible scars on the tree, and the pattern of scars tells us who was doing the drilling. Several years ago, one of our mature Hemlock Trees was utterly exploded by a lighting strike. This was an unusual event to be sure. When I was examining the remains of the tree I found a line of dark spots located deep in the tree’s heartwood. These dark spots were a record of some Sapsucker’s exploits dating back more than 100 years.

Dutchman's Breeches blooms in the old woods
The Sapsucker is also in the business of creating feeding stations for insects. The sap holes provide an easy source of sap for butterflies, beetles and other insects. These holes are particularly popular early in the season before there are many available sources of flower nectar. And early emerging butterflies like the Anglewing species are often seen partaking. Perhaps this service is not so inadvertent, for when the Sapsucker returns to her “sap-line” for a drink, she’s often inclined to eat a few of the insects that were lured in.
Flower and foliage of Perfoliate Bellwort
An interesting effect of the return of seasonable (colder) temperatures has been the preservation of some of our early blooming woodland wildflowers. Several of the flowers, which in a more normal year would’ve lost their petals in just a few days, instead retained their bloom for several weeks. Twinleaf is actually still blooming in some places around the Preserve. 

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