A quantitative comparison of the behavioral reactions of Lasius flavus ant workers (Formicidae) toward the guest beetle Claviger testaceus (Pselaphidae), ant larvae, intruder insects and cadavers

摘要

The frequency and duration of the behavioral reactions of the Lasius flavus ant workers toward the inquiline guest beetle Claviger testaceus were compared with those toward the ant's larvae, non-myrmecophilous insects and insect cadavers. The study shows that the workers behave in a similar manner to the Claviger beetle as they do with a few hours old insect cadaver, i.e. in a condition to be eaten by the brood. They lick the Claviger beetle, bite it, regurgitate ingluvial fluid on it and transport it as much as they do with an edible cadaver. Furthermore, they bite the Claviger in the same manner as they dismember dead prey. Wounded ant larvae, also, are bitten in a similar manner. The observations also indicate that the L. flavus workers do not treat the Claviger guest beetle as a social partner. The workers lick, bite and transport a Claviger beetle more frequently and for a longer duration than they do for a healthy congener worker or worker larva. Healthy gyne larvae, however, are licked as much or even more than Claviger beetles. On the other hand, healthy worker and gyne larvae, appear to benefit from more regurgitations per licking session than Claviger beetles or insect corpses. Moreover, when a worker does bite a healthy member of the society, it does so in a less severe manner than with a Claviger or a cadaver. Contrary also to Claviger beetles and insect cadavers, healthy live worker larvae are never and gyne larvae only very rarely the target of gaster flexions. When a Claviger is newly introduced in a L. flavus colony (in this case the beetle is referred to as an alien) it is the target of a high number of gaster flexions, similar to the quantity seen for non-myrmecophilous intruder insects (fruit flies and free-living soil beetles) newly introduced in a nest. When a Claviger has been present for some time in a L. flavus colony (in this case being referred to as a resident), it is the target of a lower number of gaster flexions, similar to the number received newly decaying corpses. A resident Clavigerreceives more regurgitations than an alien one. When introduced in a colony, a Claviger, alien or resident, is bitten and transported as much as some live, non-myrmecophfious, intruder insects. However, the latter are rarely, if at all, licked and never receive regurgitations. The study also shows that, in laboratory conditions, a regurgitationreleasing substance appears in insect corpses one hour after death and that the maximum quantity of this substance is produced in cadavers 5 to 7 hours after death. As the Claviger is treated in a similar manner as a few hours old corpse, it benefits from the workers' licking sessions and regurgitations. This behavior, along with dismembering bites, is, in fact, intended for the preparation of the solid food given to the brood. Morphological adaptations allow the beetle to resist the workers' dismembering attempts.