66 
Psyche 
[September 
Encounters with Predators 
ants [P ogonomyrmex badius (Latreille) ] 
The experiments were carried out under the same conditions as 
prevailed in previous comparable studies (Eisner 1958a, 1958b), the 
earwigs being affixed to rods and placed individually close to the nest 
entrance of a laboratory colony of the ant. Sheets of Kl-starch paper 
were placed under the earwigs. 
The ants at first attacked singly or in groups of two or three. No 
sooner had one of them grasped the earwig with its mandibles (often 
mere contact seemed to suffice), than the earwig responded by attempt- 
ing to catch the assailant with its pincers. Typically, the ant was 
seized and promptly removed from its hold, being released only after 
the abdomen had uncoiled and straightened out. The uncoiling of 
the abdomen is a rapid spring-like action, with the result that the ant 
is sometimes Hipped several centimeters away. 
No discharges were produced during these first attacks, all ants 
being successfully fought off by the use of the pincers alone. Gradu- 
ally, however, the activity of the ants around the nest entrance be- 
came considerably intensified (perhaps in response to the release of 
the ant’s own alarm substance; see Wilson, 1958), and within minutes 
the earwig was surrounded by a swarm of workers, some attempting 
to bite and sting it, others merely scurrying over its body. It was 
then that a discharge was finally produced. The result was an in- 
stantaneous dispersal of the entire swarm. For a few seconds there- 
after none of the ants ventured within the immediate vicinity of the 
earwig. Many showed typical grooming activities, others underwent 
the conspicuous dragging behavior already noticed in this ant and 
the related P. occidentals (Cresson) under similar circumstances 
involving insects which spray (Eisner 1958a, 1958b; Eisner et ah, 
1961). The swarm soon closed in again, but for yet another several 
seconds there occurred no real attacks, the ants turning and fleeing 
the moment they made contact with the earwig. That this avoidance 
behavior may have been attributable to residual secretion remaining 
on the earwig’s body was suggested by the fact that a small strip of 
indicator paper held within millimeters from the earwig rapidly be- 
came discolored. 
Explanation of Plate 8 
Figures 1, 2, 3. Three different discharges elicited by pinching respectively 
the end of the abdomen (figure 1), the right mesothoracic leg (figure 2), and 
an antenna (figure 3). (The pictures were taken shortly after discharge, and 
the abdomens were therefore no longer in the exact positions they had assumed 
at the time of spraying). 
