82 



ASSOCIATION OF ORGANISMS THE WEB OF LIFE 



fly (Cynips argentea) lays her eggs. The abnormal growths or 

 "galls" which result from this process secrete nectar that serves 

 to attract ants, and thus a body-guard is secured by which the 

 attacks of caterpillars and snails are repelled. The following 

 account is given by Kerner (in The Natural History of Plants] 

 of the way in which ants protect the flower-heads (capitula) of 

 certain Composites: " A similar state of affairs is met with on 



Fig. 1077. A Saw- Wort (Serratula lycopifolici) defended by Ants (Formica exsecta] against the attacks 

 of a Beetle (Oxythyreafunesta) 



the capitula of several Composites indigenous to South-eastern 

 Europe, e.g. Centaurea alpina and Ruthenica, Jurinea mollis, and 

 Serratula lycopifolia, the last of which is here figured [fig. 1077]. 

 The young heads of these Composites are particularly liable to 

 the attacks of voracious beetles, especially of Oxythyrea funesta, 

 which bites big holes in them, destroying crowded flower-buds 

 and involucral scales [i.e. the overlapping scales which surround 

 the head] without the least difficulty. To meet this danger a 

 garrison of warlike ants is employed. Honey is secreted from 



