SLUGS AS MYCOPHAGISTS 



217 



Benecke l has recently made some experiments on slugs by 

 offering them definite chemical substances ; and he has thereby 

 found : that Arion empiricorum and A. subfuscus readily consume 

 agar preparations, etc., containing sugar or proteins ; that Agrio- 

 limax agrestis prefers sugar ; and that Limax tenellus avoids sugar 

 in higher concentrations. Cubes of agar containing only water 

 or other indifferent substances were 

 refused . Certain stimulatory su bstances , 

 as Stahl found, appear to be required 

 to make the food palatable. As such 

 stimulatory substances Benecke men- 

 tions : sugar, peptone, and glycogen 

 for Arion empiricorum and A. subfuscus ; 

 sugar for Agriolimax agrestis ; and 

 glycogen for Limax tenellus. 



Slugs and Poisonous, Acrid, or 

 Cystidia-bearing Agaricineae. Certain 

 fungi which are very poisonous to man 

 are eaten with impunity by slugs. Thus 

 in August, 1922, at Earlswood, I observed 

 both Arion subfuscus and A. ater feeding 

 on Amanita pantherina ; and, as is well 

 known, one not infrequently finds in 

 English woods slug-damaged fruit-bodies 

 of the Death Cap, Amanita phalloides 

 (Fig. 77), the Fly Agaric, A. mus- 

 caria (Fig. 78), Boletus luridus, and 

 other poisonous species. According to 

 Benecke 2 Amanita phalloides, excepting the pellicle and the volva, is 

 eaten with avidity by Arion empiricorum and A . subfuscus but is 

 refused by Limax tenellus which lives largely on fungi and by 

 L. arborum which is supposed to live only on lichens. Experiments, 

 recorded in Volume I, showed that Limax maximus, Arion subfuscus, 

 and Agriolimax agrestis all eat freely of Amanita muscaria without 



1 W. Benecke, " Pflanzen und Nachtschnecken," Flora, Bd. CXI and CXII 

 (Stahl Festschrift), 1918, p. 475. . 



2 W. Benecke, loc. cit., pp. 470-471. 



FIG. 77. Amanita phalloides, 

 the Death Cap, an agaric 

 which, although very poi- 

 sonous to man, is eaten 

 with impunity by slugs. 

 The pileus shows dam- 

 age done by slugs under 

 natural conditions. About 

 the natural size. Photo- 

 graphed at Scarborough, 

 England, by A. E. Peck. 



