1988] 
Hare — Marking ant larvae 
305 
Table 1. Initial preference profiles of Leptothorax worker groups. 
Worker Species 
L. ambiguus L. longispinosus 
Groups accepting more marked larvae 
7 
8 
Groups accepting more unmarked larvae 
6 
4 
Groups accepting equal numbers of 
both types of larvae 
3 
1 
reduced sample size and does not reflect a change in the number of 
larvae in the nests of the remaining groups (see Appendix B-l in 
Hare, 1987). For the two L. longispinosus groups that were 
observed on the sixteenth day, 95% of the marked larvae and 80% of 
the unmarked larvae that were initially available remained intact 
within the nest. Without exception, marked and unmarked larvae 
were placed in a common brood pile within the nests of both species 
throughout the experiment. 
Discussion 
The introduction of larvae marked externally with Testor’s paint 
provides an inexpensive and reliable technique through which large 
numbers of internally marked larvae can be obtained rapidly 
(<24h). Fading of the mark was perceivable in some groups as early 
as six days after marking, but remained visible in others to a maxi- 
mum of sixteen days. Thus, this technique would not be useful in 
situations requiring an extended mark duration, but its utility would 
ultimately depend on the specific rate of trophallactic food 
exchange of the ants in question. The technique should also be 
limited to use with small worker groups since high rates of trophal- 
laxis between larvae and workers in full colonies can lead to con- 
tamination of unmarked larvae with the mark (Hare, unpublished 
data). However, this would not present a problem over the short 
term since “contaminated” larvae possess a very faint mark relative 
to those introduced as “marked” larvae in the first place (Hare, 
personal observation). For the purposes of our experiments with 
Leptothorax, the mark duration was more than adequate and there 
were no instances of contamination in any trial using groups of 
three workers. 
No significant preference for marked or unmarked larvae 
occurred at any time interval and overall neither L. ambiguus nor L. 
