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Posts tagged “Insect Signs

Rusty Tussock Moth Egg Case

There are many species of tussock moths, and in their larval, or caterpillar, stage, most are covered with tufts of hair-like setae, some impressively long.  The female rusty tussock moth, Orgyia antiqua, is flightless, so after emerging from her cocoon, she stays put, releasing alluring pheromones and awaiting the arrival of a male suitor.  After mating, she lays up to several hundred eggs on top of her empty cocoon and then dies.  The flat-topped, cylindrical eggs (with a dark depression on their top) overwinter, and as soon as leaf buds start opening, the eggs hatch, with ready-made meals inches away.  Larvae feed on the leaves of birches, oaks, crabapples and black cherry, among others.  Pictured is an egg mass on an apple leaf.

 


Staghorn Sumac Seed Heads and Their Inhabitants

If you pull apart a red, fuzzy seed head of Staghorn Sumac (Rhus typhina) this time of year, you will find, in addition  to a multitude of seeds, a profusion of scat in the shape of miniscule round, grey balls.  If you’re lucky, you’ll find the larval insect that produced this scat.  Chances are, according to Charley Eisman, author of Tracks and Sign of Insects, that many of the resident insects are in the Gelechioidea family of moths.  The larvae of these moths are consumers of Staghorn Sumac seeds, and judging from the amount of scat usually present, they spend a considerable amount of time inhabiting the seed heads.  It’s likely that Black-capped Chickadees and other birds you see gleaning sumac fruit are actually there  for the larvae as much as the seeds.

 

 


Ribbed Petiole Poplar Gall

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If you look at enough Trembling  Aspen (Populus tremuloides) leaves (and to some degree, those of other poplar species), you are bound to come across some that have an oval swelling about the size of a pea where the leaf  and stem, or petiole, meet.  This swelling is a gall – an abnormal plant growth caused by chemicals coming from the moth (Ectoedemia populella) that laid an egg at this spot this past summer, or from the chewing of the hatched larva as it bored its way into the stem of the leaf.  This gall provides shelter and food for the developing larva, which will, after the leaf falls, go down into the ground to pupate.  An adult moth will emerge next  spring.