A NEW METHOD FOR MARKING ANT LARVAE 
By James F. Hare 1 
Erindale College, University of Toronto 
Mississauga, Ontario, Canada L5L 1C6 
In most ethological studies, an observer must recognize individual 
animals or at least certain classes of animals in order to acquire 
meaningful information. Individual animals are distinguished either 
by morphological differences or through the application of a distin- 
guishing mark by the investigator. 
In recent studies conducted by Hare (1987) and Alloway & Hare 
(under editorial review) where brood of a slave-making ant species 
( Harpagoxenus americanus ) and host species ( Leptothorax longi- 
spinosus) were offered simultaneously to host species workers, an 
observer was required to identify the species of any given larva 
quickly and reliably. Species identification of ant larvae has tradi- 
tionally relied upon one or more of the following morphological 
characteristics: general body shape, mandible shape, pattern, struc- 
ture and abundance of hairs, location and abundance of integumen- 
tary spinules, head shape, dentition of the mandibles and physical 
characteristics of other mouthparts (see Wheeler & Wheeler, 1960). 
None of these characteristics are useful in distinguishing Harpa- 
goxenus from Leptothorax larvae (Wheeler & Wheeler, 1960; Hare, 
personal observation). Thus for our research, we required a tech- 
nique whereby larvae could be given a visible mark that would not 
bias the acceptance of marked versus unmarked larvae. 
Several techniques have been developed for marking adult ants 
(see Stuart 1986 for a review). Techniques reported for marking 
brood either damage the brood (e.g. filling eviscerated larval skins 
with coloured gelatine; Brian 1975), or the marks do not persist 
because of grooming by adult workers [e.g. spots of of coloured wax 
applied to larval cuticle (Brian 1975), bits of coloured plastic glued 
'Present Address: Department of Zoology, University of Alberta, Edmonton, 
Alberta, Canada T6G 2E9 
Manuscript received by the editor November 20, 1988. 
299 
