Pennsylvania's Invertebrates
of Special Concern

The animals constituting the loosely used term "invertebrates," comprise the large majority of Pennsylvania's animals. It's been estimated that when all the sponges, planaria, snails, spiders, millipedes, moths, beetles and other insects are added, the total would be a staggering 15,000+ species--or roughly 70 percent of all Pennsylvania's flora and fauna. Unfortunately, little is known about this large group.

Aside from their sheer numbers, these no-backbone animals are a key foundation block upon which all ecological systems depend. Hundreds of different birds and mammals, for example, depend upon invertebrate populations as food sources, and many of the higher plants rely on invertebrate pollinators and seed dispersers. Yet with all of this tremendous--in fact, critical--importance, there is one animal in particular that has yet to fully appreciate invertebrates--man.

Great strides have been made in natural resource conservation, but invertebrate animals--along with fungi, lichens, algae and a few other key groups of living organisms--have often not been included in these efforts. Although society obviously appreciates some invertebrates, such as the honey bee and its role in the pollination of agricultural crops, the understanding and, in turn, conservation of most invertebrates has lagged far behind.

Mammals, birds, reptiles, amphibians, fish and vascular plants--the larger, more obvious life forms--have official state agencies responsible for their protection and management. On the other hand, with the exception that aquatic organisms are managed by the Fish and Boat Commission, most invertebrates do not fall under the trusteeship of any such caretaker.

Fortunately, the U.S. Endangered Species Act applies to all living species, so at least some attention is focused upon invertebrates thought to be threatened or endangered on a national level. The butterfly exemplified in this site has no official status in Pennsylvania, but it is classified as a "Candidate for Review" by the U.S. Fish and Wildlife Service under the federal act. The decline of the once widespread and regularly found regal fritillary is both mysterious and alarming. Is this animal's plight another signal of an illness in our environment?

Invertebrates are excellent environmental quality barometers. Nonetheless, virtually no attention has been paid to the plight of the fritillary or virtually any other non-aquatic invertebrate. Of the 100 or so species of butterflies and skippers in our state, many are just as worthy of attention as the regal fritillary.

The northern riffelshel belongs to the family of organisms that has experienced the greatest decline and extinction of any group of species in North America: freshwater mussels. Of the 65 or so original native Pennsylvania species, 18 are no longer found here and another 20 should probably be classified as endangered or threatened. Several of the remaining 27 have also declined. Seven mussels have been listed as Endangered under the U.S. Endangered Species Act. Nine Pennsylvania mussels have been enlisted as endangered under the U.S Endangered Species Act, but seven of these are already extirpated in our state.

Although these are the only two invertebrates in this site, dozens of others have fascinating stories of their own. The Pennsylvania Biological Survey, a nonprofit research education, and conservation organization, is composed of representatives from governmental resource agencies, scientific institutions and conservation groups. The Survey's Invertebrate Technical Committee is presently investigating issues related to Pennsylvania's invertebrate resources, including the need for a state agency responsible for the myriad of interesting and diverse invertebrate groups.

Invertebrates | Birds & Mammals | Fish, Reptiles & Amphibians | Plants