Preimaginal learning as a basis of colony-brood recognition in the ant Cataglyphis cursor

Abstract

In most circumstances, social insects recognize their nestmates. They can discriminate against alien adults and also against alien larvae. Results presented here indicate that the mechanism of colony-brood recognition is acquired in large part during larval life and persists through the metamorphosis into the adult stage. During the first days after emergence of the adult, a weaker form of learning can also occur. These phenomena are discussed in relation to kinship theory. It appears that kin recognition is determined not so much by genetic relatedness as by spatial proximity of the individuals during the early stages of life.Most social insects can discriminate nestmates from nonnestmates (1). The hostility shown to adults of alien colonies is evidence of colony recognition. Recent data have revealed that intraspecific brood discrimination also exists in some ant species (2-5) and wasps; such discrimination manifests itself in differential brood-nursing activities (5-7). For the honey bee, comparable discrimination is not clearly established, as contradictory results have recently been published (8, 9).In Cataglyphis cursor Fonscolombe, brood-nursing ants prefer larvae from their own colony to those from an alien colony, which they give only half as much care as their own brood (unpublished data). We report here results that indicate an important role for learning such discrimination very early in life, during the larval stage. METHODS AND RESULTSExperiment 1: Effect of isolation during the first 10 days of adult life Young C. cursor workers were taken from their colony less than 8 hr after eclosion and were placed for 10 days in one of three situations.In one group (Gi; 98 ants) each ant was completely isolated until age 10 days. The workers were then formed into subgroups of seven workers each, and 15 min later they were tested by being offered a choice among three nestmate larvae (NL) and three alien larvae (AL). The larvae in this and other experiments were identified by sticking colored plastic spots on them. Each instance of licking or carrying of a larva for the next 15 min was recorded.In another group (G2), each of 82 young workers was familiarized with members of an alien colony, here called the "familiar colony," by being kept with two adults and two larvae (FL) from that colony for 10 days. These ants too were then formed into groups, of about seven each, and 15 min later were tested, in this case for their choice among three NL and three FL.The 98 newly hatched ants of the third group (G3) were kept for 10 days in groups of seven nestmates each and then were tested for choice among three NL and three AL.In G1 and G3, NL were clearly preferred to AL (Fig. 1) (P < 0.01) (except where noted otherwise, Wilcoxon tests were used). Early isolation as adults (Gi) did not reverse the ants' preference for their NL, although this preference was weaker than in the group kept with nestmates (G3) (P < 0.05, Mann-Whitney U test).The ants of G2 (familiarized with individuals from an alien colony) still sl...

Cognition in Invertebrates

“…Slavemaking ants invade colonies of other ant species and transport the pupae back to their own nest. Adults emerging from these pupae react and work for the slave-making species as if it were its own species (Isingrini et al, 1985;Carlin and Schwartz, 1989). The basis for such phenomenon may be olfactory imprinting processes by which the slave ants learn to recognize the slave makers as members of their own species.…”

Feel, smell and see in an egg: emergence of perception and learning in an immature invertebrate, the cuttlefish embryo

“…the capability of sensory systems to elicit behavioral responses to the appropriate type of stimuli) (Lickliter, 2005) is paired with 'immature' forms of prenatal simple learning such as habituation (Schaal, 1988;Shalev et al, 1989;Smotherman and Robinson, 1992;van Heteren et al, 2001). In invertebrates, very few studies have shown prenatal learning and this question is still debated (Isingrini et al, 1985); this constitutes the second aim of this study.…”

Larval memory affects adult nest-mate recognition in the antAphaenogaster senilis

“…However, to date, no study investigated the possible impact of cue learning during early developmental stages on discrimination between adult individuals. Since preimaginal learning of odour cues used in brood recognition has been demonstrated earlier [11,12], here we investigated whether exposure to an alien colony odour during the larval stage might affect nest-mate recognition at the adult stage, thus in a novel adult-adult context. We transferred larvae of the ant Aphaenogaster senilis for a period of time into an 'adoptive colony' of the same species to test whether adult ants, proceeding from these adoptees, would treat differently individuals belonging to the familiar, adoptive colony compared with alien, completely unfamiliar individuals.…”

“…Some important insights came from studies on preimaginal olfactory learning in formicine ants. Isingrini et al [11] introduced small and large larvae of Cataglyphis cursor ants in an alien adoptive colony where they developed until the pupal stage; at this point, they were transferred back to their original colony. After eclosion, workers originated from the small larvae group preferred to care for brood belonging to the adoptive colony rather than for their sister brood, but this was not the case for the large larvae group.…”