Article révisé par les pairs
Résumé : Laboratory experiments on circular artificial trails show that the beetle Edaphopaussus favieri follows the trail of its host ant, Pheidole pallidula. After having been isolated for a certain time, the beetle greatly improves its trail-following ability once it is again in contact with workers. The optimal response of E. favieri occurs for a concentration of 0.03 minor worker's poison glands per cm. Minor and major workers are respectively 10 and 4 times more sensitive. High trail pheromone concentrations, from 0.06 glands/cm onwards, repel the beetle, not the workers. This avoidance effect is also found with whole Ph. pallidula's poison and mandibular glands, with volatiles from the Dufour's gland and with poison gland extracts presented in the form of a dot, in front of the beetle. The trail following of E. favieri is host-specific. The adaptive value of the trail-following characterisitcs of E. favieri is discussed. © 1990 Masson.