1988] 
Hare — Marking ant larvae 
301 
with the paint. Between 31.5% and 85.7% of the previously un- 
marked larvae became marked internally, thus providing a minimum 
of 6 and a maximum of 34 marked larvae in the test colonies. The 
colour red was selected for use in all experiments because ants are 
not sensitive to light of this wavelength (Wilson, 1971), thus 
reducing the possibility of any visually mediated bias in larva 
acceptance. 
To test for any influence of the mark on larva acceptance, an 
experiment was performed. Internally marked larvae were obtained 
by covering the mouthparts and at least 50% of the cuticle of several 
L. ambiguus larvae with Testor’s red enamel and placing these lar- 
vae inside an L. longispinosus nest. Adults of the recipient colony 
cannibalized these larvae and in most cases fed this material to their 
own larvae. Allospecific larvae were used to ‘transmit’ the mark 
since they are less likely to be accepted for tending (see Hare and 
Alloway, 1987) and are thus more likely to be cannibalized. 
On the next day, worker groups were established by choosing 
three L. longispinosus workers arbitrarily from each of 13 colonies 
and placing each group in a new culture dish with a nest, water vial 
and food (see Hare and Alloway 1987). Groups were allowed 24 
hours to explore their new environment prior to testing. 
Since Plateaux (1960) found that Leptothorax nylanderi workers 
could only distinguish between conspecific larvae and Solenopsis 
fugax larvae when conspecific larvae were present, larvae of the two 
‘types’ were offered simultaneously to the workers. Under this pro- 
tocol, a single larva of each ‘type’ (marked and unmarked) were 
placed on a clean glass coverslip and positioned immediately in 
front of the nest entrance. Within each pair, larvae were matched 
visually for size and placed as close together as possible, (but not in 
physical contact) in the centre of the coverslip. Workers were 
allowed to retrieve one larva into their nest, their choice was 
recorded, and a new pair of larvae was presented. Paired presenta- 
tions of this sort continued until the supply of either marked or 
unmarked larvae for a given donor colony was exhausted. For the 
13 worker groups (replicates) the number of initial paired presenta- 
tions ranged from one to 12 (8.2 ±0.8 presentations [mean±SE], 
mode=10 presentations). Since each worker group was derived 
from a separate maternal colony, replicates were independent and 
the difference in the number of the two types of larvae accepted in 
