10 WOODLICE 



of one individual were found to include moss capsules and part of 

 a syncytium of Vaucheria. 



The small, myrmecophilous Platyarthrus hoffmannseggi feeds on 

 fungi and their spores, the excreta of ants and other vegetable 

 matter. Some species, especially Oniscus asellus, are decidedly more 

 omnivorous than others such as Porcellio scaber which confines its 

 diet largely to the bark of trees and Trichoniscus pusillus which 

 lives almost entirely on decaying leaves. According to Bristowe 

 (1941)*t) woodlice will eat spiders' eggs in captivity, and as they 

 are often to be found in untenanted cells beside empty egg-sacs 

 it can be supposed that they devour Arthropod eggs whenever an 

 opportunity occurs. Armadillidium vulgare requires chalk in its 

 diet, and this may be correlated with its exceptionally thickly cal- 

 cified integument. 



Enemies 



Woodlice are eaten by birds, reptiles, amphibia, and many other 

 insectivorous animals including spiders, harvest-spiders, mites and 

 centipedes. The number of species of spider which will destroy a 

 woodlouse is, however, somewhat limited. Armadillidium vulgare 

 rolls into a ball directly it is attacked, and its hard, thick integument 

 saves it from injury, even from large species such as Tegenaria 

 atrica and Araneus diadematus. According to Bristowe (1941)* 

 Porcellio y Oniscus and Philoscia spp. secure some protection from 

 the chitin with which their dorsal surface is covered so long as they 

 remain dorsal surface uppermost. In addition they are distasteful 

 to most spiders, which reject them except in times of food shortage 

 when their normal aversion is overcome by hunger. Distastefulness 

 is most marked m Porcellio spp. and least in Philoscia spp. (except 

 ior Platyarthrus hoffmannseggi whose myrmecophilous habit renders 

 it least likely to attack by spiders). On the other hand the cave and 

 cellar spider Meta menardi often owes its survival in subterranean 

 situations to the presence of woodlice, and Dysdera crocota and 

 D. erythrina have jaws specially adapted to grip and penetrate the 

 crustacean cuticle. 



At one time it was believed that certain tegumental glands 



t For references marked with an asterisk see bibliography of general 

 works at the end of the volume. 



