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| White furcula moth - Furcula borealis |
The best way to find small insects is to take WOLF School students on a field trip. At Bull Creek last week our focus was on plants and leaves but inevitably a sharp eyed student will say "What is this?" and viola! an insect. They had two great finds, very small caterpillars.
The caterpillar above is
Furcula borealis, the white furcula moth. It has two long tails off the tip of its abdomen
(Furcula means forked). The green and brown camouflage mimics a damaged leaf. The curved posture is typical, seen in
most of its photographs. They are usually found from April to late August when the second brood cocoons up for the winter. Our friend put on quite a show of
evasion techniques in this video.
They feed on
Prunus species (plums, cherries, peaches, nectarines, apricots, and almonds), cottonwoods, and willows like our specimen was munching. We tried raising ours on willow but it failed to thrive after a week.
Norman and Cheryl Lavers on the other hand found a
F borealis caterpillar in its last stage and document it with this beautiful series of photographs of the rest of its life cycle.
"We found this caterpillar feeding on black cherry in our garden, and brought it in to raise. Eventually it was woven so tightly it was opaque, and had taken on the
color of the stick it was attached to. Looking like a thickening in the
wood, it would spend the winter in plain sight. On this date the caterpillar attached itself to a narrow stick and wove a
thin cage around itself, inside which it could be seen weaving a more
solid cocoon. It somehow pushed a hole in the rather thick cocoon the following April."
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| Buckeye the butterfly - REK |
The other lepidoptera find of the day was the colorful caterpillar on the right which we quickly identified on INaturalist as a common buckeye,
Junonia coenia. They are found from the East to the West Coast. Buckeyes have been among our most commonly seen butterflies the last few weeks.
This is the time of year when the buckeye tree's seeds are dropping to the ground but
the timing is coincidental. Buckeye butterflies are named for the
"buck eyes" on their dorsal wings, not their choice of foods.
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| Side view |
The caterpillars of these butterflies prefer plants that produce iridoid glycosides, bitter compounds that release a hormone called gastrin
that activates the digestive system and stimulates their appetites,
particularly when found in plants like one of our common yard weeds, plantain, Plantago lanceolata or P. major. They also feed on snapdragon and toadflax. I suspect I would need an appetite stimulant to eat something called toadflax.
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Just emerged September 28th.
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| Just emerged |
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| Empty chrysalis |
The caterpillar above is Furcula borealis, the white furcula moth. It has two long tails off the tip of its abdomen (Furcula means forked). The green and brown camouflage mimics a damaged leaf. The curved posture is typical, seen in most of its photographs. They are usually found from April to late August when the second brood cocoons up for the winter. Our friend put on quite a show of evasion techniques in this video.
