Table 2.

Data representing attacks on butterfly models at field sites in Costa Rica and Panama, categorized by aggregation size. Roost attack risk was calculated by dividing attacked roosts by the overall number of roosts used in that treatment. Individual attack risk was determined by comparing attack rates between randomly selected single (focal) individuals in each roost treatment, based on the assumption that one attack leads to the dispersal of the other roosting butterflies. Probability values between pairwise comparisons are indicated by asterisks.

aggregation size	total observations	roosts attacked	attack risk (per roost, %)	attack risk (per individual, %)
Costa Rica
single individuals	320	68***	21.3	21.3***
roost of five	320	25	7.8	3.4
Panama
roost of two	200	21*	10.5	9.5**
roost of five	200	8	4.0	1.5
roost of 10	200	*24	12.0	4.5

*p < 0.05.

**p < 0.001.

***p < 0.0005.