1981] Holldobler — Communication in Orectognathus 255 
Discussion: 
It has been well documented that many species of the sub-family 
Myrmicinae employ secretions from the glands associated with the 
sting apparatus (poison gland, Dufour’s gland) for chemical trail 
communication and orientation (for review see Wilson 1971; Holl- 
dobler 1978). This paper presents the first evidence of the phenom- 
enon in the myrmicine tribe Dacetini.* 
In the dacetine species Orectognathus versicolor trails laid with 
poison gland secretions function both as recruitment and orienta- 
tion signals during nest emigration. In fact, many dacetine species 
seem to construct relatively simple nests in soil or rotting wood and 
it is easily conceivable that colonies frequently abandon their nests 
and move to new nest sites. More surprising, however, was the 
discovery that this species possesses a pygidial gland whose struc- 
ture closely resembles that of the pygidial gland of some ponerine 
species. The secretions of this gland can also function as a recruit- 
ment trail pheromone in O. versicolor. 
Table 1. Number of workers following artificial trails within 5 min. periods. The 
means and standard deviations are given. 
Trails presented at nest entrance (n = 4) 
Dufour’s 
water 
Poison 
water 
Pygidial 
water 
gland 
control 
gland 
control 
gland 
control 
0 
0 
12.7 ± 3.8 
0 
8.3 ± 2.8 
0 
Trails presented simultaneously at periphery of clustered colony (n = 5) 
Dufour’s gland 
Poison gland 
Pygidial gland 
with 
brood 
without 
with brood without 
with brood 
without 
incl. 
males 
brood 
inch males brood 
incl. males 
brood 
0 
0 
7.8 ± 3.8 7.0 ± 2.2 
2.0 ± 1.6 
9.8 ± 3.1 
*Blum and Portocarrero (1966) demonstrated that three attine ant genera follow 
trails drawn with poison gland secretions of Daceton armigerum, but they could not 
demonstrate trail following behavior in Daceton. 
