July 24th
- August 21st. I was walking along the trail by the lake in a deciduous forest
with some…
Post Oak (Quercus
stellata) saplings.
Something caught my
eye. It took a couple of seconds to process what I was seeing…
A closer view.
Each larva was approximately
3/8th inch long and 1/16 inch diameter. They had black heads; their
T1 segment was tan with a dark band. They had short black horns and fine setae
(hairs) on their abdominal segments.
A few larvae at the
lead were evolving to the next instar stage; they had enlarged black heads, darkened
thoraxes and abdomens with hints of lighter stripes, and longer setae than most
of the larvae.
I wasn’t sure how
fast these larvae would develop so I went back on July 25th to
photograph them again. At first I could see no sign of them. It was hard to
imagine that the small larvae I had seen the day before could have disappeared
completely. Then I looked on the underside of a leaf where I found the…
remains of the casings of the eggs
from which they had hatched.
I found two groups
of instars under different leaves. Apparently they had sheltered there during
the night. All of the instars now had black heads.
My next visit was
on July 29th.
I was a little
anxious for them. They had almost depleted the leaves on this particular
sapling. There were no other Post Oak saplings in the immediate vicinity, although there
was one directly across the trail. When I returned the following week, I
couldn’t find any sign of them.
I identified the
larvae as an Anisota (Oakworm Moth) larva, either Anisota senatoria or A.
peigleri. I submitted photos of the instars to Bug Guide, where they were
identified as larvae of A. peigleri, the Peigler’s Oakworm or
Yellowstriped Moth.
I thought that was
the end of it – for this year. Then, on August 21st, when I was
checking some bracket fungi approximately a half a mile from the location where
I had found the first instars, I noticed another sapling that had been
completely denuded. There were a few Post Oak saplings nearby and, not
expecting to find anything, I climbed the embankment to examine them – just in
case. To my delight, I found three…
stage 4 larvae,
obviously from a different hatching. But it was nice to find some mature
larvae. It was great to see the final stage after having seen the earliest
stages.
Anisota peigleri is
one of six species in the genus Anisota. The larvae of Anisota senatoria and A.
finlayson are similar in appearance to A. peigleri and are assigned to the senatoria
group. Larvae in this group are black with yellow or orange stripes; larvae of
other species are different colors. A. senatoria is found in the eastern U.S.
but not in the deep south or northern areas. A. finlayson is found in Ontario
and Quebec. A. peigleri is found in the southeastern U.S. from the mountains of
Virginia, Kentucky, and Tennessee to central Florida.
References:
- Bug Guide: Genus Anisota.
- UF/IFAS: Yellowstriped Oakworm (suggested common name), Peigler's oakworm, Anisota peigleri Riotte(Insecta: Lepidoptera: Saturniidae)
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