HR. I. ENT. NAT. HIST., 7: 1994 



IW 



ANTS FEEDING DIRECTLY ON PLAN1 SAP 



Richard A. Jones 



13 Bellwood Road, Nunhead, London SEI5 3DE. 



In my small front garden, the large coltsfoot-shaped leaves of Ligulariu deniata 

 (Gray) Hara (Asteraceae, = formerly Compositae) became slightly damaged through 

 being knocked by the wind against the adjacent garden wall. Some of the leaves showed 

 small tears a few centimetres long, which quickly became browned along the ragged 

 edges. The leaves of this large garden ragwort are tough and leathery, the damage 

 was minor and the large yellow flowers were unharmed, so I ignored the insignificant 

 cuts on a few of the leaves. 



However, during several warm days in June, July and August 1993, I noticed thai 

 ants were congregating along the edges of these cuts. They were foraging workers 

 of the extremely common 'pavement ant', Lasius niger (L.) and they appeared 

 to be biting at the edges of the tears in the leaves. Each of several leaf abrasions 

 had two or three ants, seeming to focus their attentions on particular points. Some 

 of the longer tears (10 cm or so) had perhaps five or six ants both above and below 

 the leaf surface, biting at particular points along the very edge of the leaf tear. 



Examination of the leaf lacerations under a hand lens showed that when fresh, 

 sap oozed from cut edges. A day later, a tear would be browned, and the sap 

 appeared to have crystallized, giving the edge a glinting sugary appearance. The 

 ants appeared to be feeding on this crystallized sap. It is possible that their feeding 



Fig. 1. Three ants (Lasius niger) intent on a particular spot along a tear in the leaf of Ligularia 

 dentata, where they appear to be feeding on the crystallized sap of the plant. Photo: R. A. Jones. 



