1987] 
Peeters & Crewe — Ophthalmopone berthoudi 
207 
on their return. Similarly, scouts in Pachycondyla tesserinoda de- 
posit and use scattered chemical orientation marks which have no 
recruiting effects (Jessen and Maschwitz, 1985). 
Foraging originated from every nest and marked hunters were 
always recorded as returning to their nest of origin in a colony. 
Some foragers did not hunt around their own nests, and travelled 
long distances to hunt in areas nearer other nests in the colony, 
where they had been observed to be previously active. On consecu- 
tive days, the same individuals returned to the same part of their 
colony’s home range. 
Discussion 
Ophthalmopone berthoudi invariably hunts alone; this is in 
conflict with previous references to this genus in the literature. 
There is no cooperation among foragers, either through the transfer 
of information about the location of new sources of prey, or 
through direct assistance during the killing and retrieving of prey. 
Many other species of ponerines are also solitary predators (Table 
1), although they are in many cases more opportunistic in their 
choice of prey. Group retrieving (involving a small number of 
workers) is occasionally seen in some species of solitary hunters 
(when prey is too large or numerous to carry), but this cooperation 
is not always a consequence of recruitment, i.e. a huntress can 
attract nestmates in her immediate vicinity through the release of 
alarm pheromones ( Amblyopone pallipes; Traniello, 1982), which is 
not equivalent to returning to her nest to recruit one or more nest- 
mates to the prey (e.g. Rhytidoponera purpurea; Ward, 1981). In 
Plectroctena conjugata (Peeters, unpublished), several foragers are 
sometimes led together to a hunting area, but they capture prey and 
return to the nest independently. 
Solitary predation contrasts with the elaborate systems of 
recruitment and cooperative hunting displayed by other ponerine 
species. Fletcher (1973) has critically reviewed column-raiding in the 
Ponerinae. The comparative overview in Table 1 reveals that simple 
and complex hunting strategies occur in different species irrespec- 
tive of phylogenetic relationships. Thus O. berthoudi and Mega- 
ponera foetens are closely related (W. L. Brown, pers. comm.) but 
