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SLUGS AS MYCOPHAGISTS. 
By Professor A. H. R. Buller, D.Sc., Ph.D., F.RS.C. 
INTRODUCTION. 
Slugs eat many fleshy fungi; and in woods and gardens one 
can often find fruit-bodies which have been more or less damaged 
by these animals. Fungi, therefore, especially in certain localities 
and in certain seasons, must be considered as an important 
source of slug food. Among the fungi which slugs attack may 
be mentioned: species of Amanita, Pleurotus, Russula, Psalliota, 
Coprinus, Boletus, Polyporus and Phallus. Leathery fungi, e.g. 
Polystictus versicolor, Stereum hirsutum and Schizophyllum com- 
mune, and gelatinous fungi, e.g. Hirneola auricula-Judae and 
Auricularia mesenterica, are generally avoided*. 
A fruit-body which has been partially eaten by a slug can be 
easily recognised: (1) by the peculiar manner in which it has 
been rasped and mined, and (2) by the slug’s slime tracks. Slugs 
are nocturnal animals. During the day, they hide under soil 
or in dark crevices; but, as darkness comes on, they emerge 
from their places of concealment and seek their food. They 
therefore visit the fruit-bodies of fungi during the night, but, 
as a rule, retire from them with the advent of day. Sometimes, 
however, a slug which has made a hole on the under side of 
the pileus or in the top of the upper part of the stipe of a large 
agaric, such as Boletus luteus or Lactarius piperatus, remains 
half-hidden in the hole throughout the day and then may be 
found by the observer. 
SLUG-DAMAGED FUNGI IN AN ENGLISH WOOD. 
On September 8, 1920, accompanied by Mr W. B. Grove, 
I spent an afternoon in a wood at Earlswood, near Birmingham, 
England, investigating the damage which the slugs had done 
to the fungi. Out of several hundreds of fruit-bodies of fleshy 
Hymenomycetes observed, I found very few which had not been 
visited and partially eaten by slugs. Some of the fruit-bodies 
had been absolutely ruined by these animals. Thus the stipe 
of a large Boletus flavus had been eaten in two; and the separated 
pileus had completely lost all its hymenial tubes, whilst the 
pileus-flesh had become reduced to a thin perforated shell. 
A slug was found ensconced in one of the cavities of the flesh; 
and, doubtless, it was only waiting for the night to sate its 
voracious appetite once more upon the wreck to which it was 
* A few experiments upon the edibility of fungi for slugs are recorded in my 
Researches on Fungi, I, 1909, p. 229. 
