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Table 2. Number of workers of Meranoplus sp. no. 1 1 following artificial trails 
drawn with crushed poison and Dufour’s glands. All ants following the trail at least 
through 10 cm during a 2 minute observation period were counted. The means and 
standard deviations of a total of 6 experiments for each combination are given. 
Poison gland vs water 
Dufour’s gland vs water 
Poison gland vs Dufour’s gland 
26.17 + 8.80 0 
4.17+1.72 0 
24.00 + 6.13 8.33 + 4.32 
experimental results I conclude that these long lasting routes are 
marked with Dufour’s gland secretions. 
Finally, I could not find evidence that the trail pheromones of 
Meranoplus are species specific. Meranoplus sp. no. 1 1 readily 
responded to poison gland trails of Meranoplus hirsutus. When 
glandular secretions of both species were offered simultaneosuly in a 
choice test, there was no preference for the conspecific poison or 
Dufour’s gland trails. Meranoplus sp. no. 1 1 followed the poison 
gland and Dufour’s gland trails of Meranoplus spp. no. 12, 13, 14, 
and 15. Similarly, Meranoplus sp. no. 14 followed trails drawn with 
poison or Dufour’s gland secretions of M. hirsutus, M. spp no. 11 
and 14. 
Repellent secretions in the Dufour’s glands 
Most Meranoplus species studied became motionless and assumed 
a pupal position when they were mechanically disturbed. In con- 
trast, M. hirsutus workers arched their gasters upright and extruded 
a whitish, sticky substance at the tip of the exposed sting (Fig. 4a). 
The same defense behavior could be observed when M. hirsutus 
foragers encountered other ant species, especially at a food source 
(Fig. 4b). The secretions, which originate from the Dufour’s gland, 
elicit a strong repellent effect in other ant species such as Campono- 
tus consobrinus, Polyrhachis sp. and Rhytidoponera sp. I was 
unable to test whether the Dufour’s gland secretions of the other 
Meranoplus species studied have a similar defensive function in 
interspecific interactions. 
Nest site marking 
In the laboratory nests of Meranoplus sp. no. 11 I noticed that 
within a few days the paper floor of the foraging arena was marked 
with fecal droplets. These markings increased in density near the 
nest and were especially conspicuous directly at the nest entrance 
(Fig. 5a). 
