Invertebrate Zoology

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Bug facts

Some Common Caterpillars are Dangerous to Touch 

Although the vast majority of caterpillar species are harmless, a few species have hairs or spines that can sting, resulting in local inflammation and discomfort to hands and areas of sensitive skin. The mature caterpillars of one local species, the hickory tussock moth (Lophocampa caryae), are covered with fuzzy white-and-black hairs (called setae) that can cause serious complications if they are accidentally introduced into the eyes. This most frequently happens to small children who have touched caterpillars with their fingers and unknowingly picked up tiny setae. These setae are microscopically barbed and stay attached to the fingers. When the child rubs his or her eyes, setae may enter the eyes and over time penetrate to a level where medical attention is required.

cocoon        lophocam 
Hickory tussock moth cocoon   Mature larva of the hickory tussock moth (Lophocampa caryae)

The tiny hairs are grown by caterpillars in their final stage of development, and are transferred by the pupating larva to the outside of its spherical silken cocoon where the hairs serve as a defense against predators. The cocoons are constructed under bark of trees or objects on the ground, and can be found throughout the late summer, fall, winter, and spring months. The caterpillars are active from July to October but are most abundant in August and September. People should not touch or handle caterpillars or cocoons of this moth species, and in general should avoid handling any caterpillar that appears spiny, hairy, or fuzzy unless they know with confidence that it is a harmless species. The above photos illustrate a mature larva and a cocoon of the hickory tussock moth, both potentially dangerous to touch.

The pictures below show other caterpillars that are extremely similar, but harmless. Caterpillars are wonderful animals, and most cause no problems. However, it is always best to admire them without handling so as not to harm them. If you need to move them, scoop them into a jar or can, or let them crawl on a stick or other object without touching them directly.

apatelod    acronict 
Apatelodes torrefacta    Acronicta rubricoma 
colocasi    halysido 
Colocasia species   Halysidota harrisii 

Lady Bird Beetles are Really Japanese 

People all over Pennsylvania complain about ladybird beetles coming into their houses. These beetles are not native to North America; rather, they were introduced intentionally from Japan by our own government to help control crop pests. As larvae and adults, ladybird beetles eat other small insects and are beneficial, but with a thousand of them in your kitchen you might begin to question that!

Strange Beetles Found near Local Slag Dump 

slagColeopterists at Carnegie Museum found two species of ground beetle adjacent to slag dumps at Pittsburgh's local Nine Mile Run, just east of the Squirrel Hill Tunnel on Route 376. In a survey of these highly disturbed habitats, museum specialist Robert Davidson found 135 different ground beetle species. Many of them were common, but among them were two species never before recorded from Pennsylvania. A single specimen of Acupalpus nanellus was captured in 1998 and constitutes the first recorded in Pennsylvania although it is already well known from Wisconsin to Nova Scotia. Two specimens of the tiny Paratachys oblitus were also taken in 1998, and although common further east, it was not previously recorded from Pennsylvania. These discoveries generate optimism for the condition of local natural habitats because things must not be too bad if new records of beetles can be found near the slag piles in Pittsburgh's backyard!

Pennsylvania Moth New to Science 

metarrhaEntomologists at Carnegie Museum discovered a species of moth in the mountain just west of Tyrone, Pennsylvania (near Altoona), that was previously unknown to science. The new species has since been found in the Allegheny National Forest, in various places in West Virginia, and elsewhere in the northeast. It flies only from late March to earliest May and is a delicate buffy pink in color. The species is easily confused with other named species that fly from mid-May to mid-June in the same habitats. Many species of local insects are overlooked in this way because they look like other species that are common and widespread.

Fluorescent Pink Katydid not a Hoax 

pink katydidEvery year in Pennsylvania mountains a few people are fortunate enough to see an amazing thing: a normally green katydid that is brilliant pink—eyes, antennae, legs, everything. This unusual insect is actually a rare variety of one of our common katydids that is normally green all over. The bright pink condition is beautiful and startling to behold, and is caused by a genetically determined condition called erythrism. The pink katydids act just like green ones, and if we are lucky, they will continue to prosper as a special Pennsylvania oddity that most of us will never see alive!

Scorpions Alive and Well in Pennsylvania 

Although confirmed records of scorpions in Pennsylvania seem to be missing, Carnegie Museum entomologists have confirmed the natural occurrence of one species in the state, Vaejovis carolinianus. A specimen was taken in Washington County near Meadowlands and is a species often found in rocky hillside habitats from Kentucky and Tennessee to the Carolinas and Georgia. This record may be the northernmost record for this species.

Giant Caterpillar Scares Children but Can't Hurt a Fly 

regalThe largest moth species in Pennsylvania, or at least the one with heaviest body weight, is the regal moth Citheronia regalis. Its larvae is truly huge—the size of a large cigar—with orange and blue coloration. It has large spiny horns just behind the head, and when touched will rear up and bristle these in the face of an intruder or curious child. It's all a bluff, as the horns are soft and about the only thing this huge caterpillar might do is give you a painless nip with its powerful teeth. The species has been slowly becoming much less common, in part due to the distraction of female moths by electric lights outdoors, and in part due to being heavily parasitized by a fly that was introduced as a pest control agent many years ago.