1981] 
Kearns & Yamamoto — Gargaphia 
221 
There were always a few nymphs that remained behind or that 
failed to keep up with the bulk of the aggregation. These slower 
individuals wandered out onto other leaves but did not settle down 
until they found the group. Apparently the nymphs maintain 
locomotor activity unless they have sufficient physical or chemical 
contact with other nymphs. There were variations in the female’s 
behavior (Table 1), but it was not obvious what environmental 
conditions might cause the female to include or change a particular 
element of her behavior. When an aggregation of first and/or 
second instars was alarmed, the group was likely to relocate on the 
same surface of the leaf rather than to move to the opposite surface 
or off the leaf. 
Certain elements of the female’s behavior were clearly recogniz- 
able and repeated more than once. These elements are recorded in 
Table 1 with the frequency of their occurrence in 18 different 
experimental responses to alarm pheromone. In 89% of the alarm 
responses, the female exhibited at least one of the first 4 elements 
Figure 2. Adult female of G. solani positioned at the extrance axil during an alarm 
response. 
