American annelid fauna has been seriously disturbed 

 by the widespread invasion of introduced Lmnbricus 

 terrestris and Allolobophora caliginosa. These spe- 

 cies are found in forested areas, especially along 

 rivers to which they have been carried by fishermen. 

 In some localities, their activities have altered the 

 basic character of the soil to the jeopardy of the en- 

 tire original forest community. 



The gastropod fauna is rich in moist, humus soil, 

 but becomes scarce when the soil dries out. It is more 

 abundant in deciduous than coniferous forests, be- 

 cause coniferous forest soils tend to be acid. In east- 

 ern North America there are three common genera 



of slugs, Philomyciis. Deroceras, Pallijera, and a va- 

 riety of snails belonging principally to the Poly- 

 gyridae, Zonitidae, Entodontidae, Haplotrematidae, 

 Pupillidae, and Succineidae. Fifty species of snails 

 were collected in 74 hours of searching in the Great 

 Smoky Mountains (Glenn Webb). The haplotremes 

 are carnivorous, feeding on other snails, but other- 

 wise the gastropods feed chiefly on detritus, algae, 

 lichens, and fungus. 



The assemblage of small animals that dwells un- 

 der stones, rotting logs, and the bark of trees is some- 

 times called cryptozoa. Many species occurring in 

 tliis microhabitat also commonly occur through the 

 litter and soil generally, especially in moist climates 

 with rich soil humus. In temperate forests, however, 

 some snails, sowbugs, some spiders, lithobiid centi- 

 pedes, julid and polydesmid millipedes, entomobryid 

 springtails, roaches, earwigs, staphylinid, carabid and 

 histerid beetles, and some ants reach maximum popu- 

 lations as cryptozoa (Cole 1946). The cryptozoan 

 habitat is a favorite of salamanders. Many common 

 soil animals are found as well in the special tree-hole 

 forest microhabitat (Park et al. 1950) ; indeed, some 

 species are specifically limited to tree-holes. 



Decaying logs and stumps are preferred by many 

 species. During the first three years following the 

 cutting of the pine trees in a North Carolina stand, 

 130 species of insects, myriapods, annelids, mites, and 

 mollusks were found (Savely 1939). Coleoptera was 

 by far the most numerous order of insects. Of all spe- 

 cies, approximately 7 per cent were phloem-feeders, 

 1 5 per cent sapwood-feeders, 44 per cent rotten wood- 

 and fungus-feeders, 30 per cent predaceous, and 4 

 per cent parasitic. The- phloem-eaters were most nu- 

 merous during the first year. Their mode of feeding 



FIG. 9-10 Foliage Insects 

 of coniferous forests, 

 (a) sawfly larvae, 

 Neodipr'ion lectonei, on 

 jack pine; (b) spruce 

 budwornn eggs, larva, 

 chrysalis, and nnoth 

 (courtesy U.S. Forest 

 Service). 



34 



