46 
Psyche 
[Vol. 95 
instar, which might be expected to change as mobility increases with 
larval size and as availability of food and presence of predators 
changes through the larval season. Larvae of the buckmoth, Hemi- 
leuca lucina Hy. Edw. (Saturniidae), provide an excellent example 
for comparison with tent-making species. H. lucina larvae lay silk 
trails, probably with a chemical marker, as do H. oliviae (Capinera, 
1980) and move with tandem trail-following. H. lucina larvae often 
defoliate portions of the hostplant, Spiraea latifolia (Ait.) Borkh. 
(Rosaceae) and the aggregations are then forced to move to new 
feeding sites. Even newly-hatched larvae move substantial distances 
relative to their size to find food (Bowers and Stamp, unpubl. data). 
Larvae also may move distances of 3 m or more for thermoregula- 
tion, when they are attacked by predators and parasitoids, and when 
they molt (Bowers and Stamp, unpubl. data). 
Transient polyethism in some tent caterpillars (e.g. M. america- 
num) may be associated with central-place foraging, web mainte- 
nance and group cohesion (Greenblatt and Witter, 1976; Edgerly 
and Fitzgerald, 1982). In contrast, H. lucina larvae would be pre- 
dicted to exhibit patterns of individual behavior different from 
Malacosoma species because H. lucina larvae are nomadic foragers, 
do not construct webs and exhibit a declining tendency to aggregate 
over development that occurs sooner than in Malacosoma species. 
Our objective was to examine individual variation in activity, 
using distance traveled as an index, in larvae of H. lucina. Specifi- 
cally, we determined: 1) whether larvae were consistently slow, fast 
or intermediate travelers relative to the group when tested several 
times within an instar, 2) whether patterns of larval activity (as 
measured by relative distance traveled) were consistent across 
instars, and 3) whether larval activity was correlated with larval 
weight. 
Methods 
Four egg masses of H. lucina were collected from a population in 
Dover, Massachusetts. The groups were reared separately on S. 
latifolia in petri dishes. During the first through third instars, larvae 
were kept in a growth chamber at 25° C day: 20° C night, with a 
photoperiod of 16 h day: 8 h night. For the remaining instars, larvae 
were reared in the laboratory at 25° C in large plastic containers (46 
X 30 X 7 cm) to prevent overcrowding. 
