FIG. 9-7 Some Inhabitants of the 

 ground stratum in a temperate 

 deciduous forest, (a) camel cricket, 

 (b) yellow-margined millipede, (c) 

 round red millipede, (d) Mesodon 

 pennsylvanicus, (e) Allogona profunda, 

 (f) Anguiipira alfernafa, (g) Anguhpira 

 kochi, (h) Haplofrema concovo ( Shelf ord 

 1913). 



^m::- 





^ "^ 



ing the winter months (Macfadyen 1952). In a hem- 

 lock-yellow birch forest in Michigan, mites and 

 springtails were over twice as numerous in winter as 

 in summer (Wallwork 1959). 



There are two main groups of annelids in the soil, 

 the large red earthworms, Lumbricidae and Mega- 

 scolecidae, and the small, whitish potworms, Enchy- 

 traeidae. In rich, moist, humus soil, the red annelids 

 may reach populations of over one hundred individ- 

 uals per square meter ; potworms sometimes occur 

 in hundreds of thousands per square meter. Earth- 



worms ingest particles of mixed humus and mineral 

 soil, absorb the organic matter out of them, and 

 defecate around the entrances to and along the length 

 of their burrows. Potworms feed more on plant and 

 animal detritus, but may ingest some mineral parti- 

 cles. Potworms may also exert some control over 

 parasitic nematodes of plant roots (Kiihnelt 1950, 

 Jacot 1940). Minimum numbers in Wales occur in 

 late winter, maximum numbers in the early summer, 

 and the biomass varies concomitantly from 2.7- 

 13.2 g/nr (O'Connor 1957). The native North 



FIG. 9-8 Wood-eating beetle, Posso/us 

 cornuius. Top left, adult; top right, 

 pupa; bottom, larva (Shelford 1913). 



132 Habitats, communities, succession 



