“You are what you eat”: Diet modifies cuticular hydrocarbons and nestmate recognition in the Argentine ant, Linepithema humile

Abstract

Nestmate recognition plays a key role in the behavior and evolution of social insects. We demonstrated that hydrocarbons are the chemical cues used in Argentine ant, Linepithema humile, nestmate recognition, and that these hydrocarbons can be acquired from insect prey. Consequently, Argentine ant cuticular hydrocarbon patterns reveal the same hydrocarbons present in their diet. Diet alters both the recognition cues present on the cuticular surface and the response of nestmates to this new colony odor, resulting in aggression between former nestmates reared on different insect prey.

An Alpine ant’s behavioural polymorphism: monogyny with and without internest aggression inTetramorium alpestre

“…At least for this study, the variation in behaviour seems not to be substantially spatially or genetically determined (unless the neutral variation detected by microsatellites is not representative of the variation encoding aggressive behaviour). Rather, the behavioural variation observed might depend on (i) the context as suggested, for example, for L. austriacus (Steiner et al 2007), or (ii) the experience of workers in previous encounters with non-nestmates (Van Wilgenburg et al 2010), or (iii) environmentally derived cuticular hydrocarbon cues (Liang & Silverman 2000). Furthermore, recent studies regarding correlations between behaviour and, for example, spatial distance revealed contrasting results: in some cases, spatial distance and aggressive behaviour were correlated (Pirk et al 2001; Benedek & Kobori 2014; Frizzi et al 2015; Fournier et al 2016), while in others, no correlation was observed (Langen et al 2000; van Wilgenburg 2007; Martin et al 2012), corroborating the general need for further studies.…”

Diet-Related Modification of Cuticular Hydrocarbon Profiles of the Argentine Ant, Linepithema humile, Diminishes Intercolony Aggression

“…Furthermore, our preliminary analysis indicated that both hydrocarbons were readily acquired by Argentine ants. For S. longipalpa, we selected 15,19-dimethylheptatriacontane present in S. longipalpa at 19.0% and acquired by Argentine ants from S. longipalpa prey (Liang and Silverman, 2000;Liang et al, 2001). To compare changes in individual hydrocarbon levels (average level on day 140 vs. average level on day 0), we used one of two types of t-tests, depending on the equality of variances.…”

“…The signals used in nestmate recognition are primarily under genetic control; however, exogenous cues derived from nest materials (Gamboa et al, 1986;Stuart, 1987) or diet (Jutsum et al, 1979;Obin and Vander Meer, 1988;Le Moli et al, 1992;Liang and Silverman, 2000) may also play a role. Cuticular hydrocarbons have long been considered important mediators of nestmate recognition in ants (Vander Meer and Morel, 1998), with recent evidence supporting a direct role (Lahav et al, 1999;Liang and Silverman, 2000). However, the relative contribution of heritable and environmentally derived cues, including hydrocarbons, to the recognition profile is not known.…”

“…Introduced L. humile populations are unicolonial and frequently very large, and they often dominate native ant species (Suarez et al, 1999). Nestmate recognition in the Argentine ant is influenced by genetic (Tsutsui et al, 2000(Tsutsui et al, , 2003Suarez et al, 2002) and environmental (Chen and Nonacs, 2000;Liang and Silverman, 2000) inputs. Holway et al (1998) and Suarez et al (2002) reported that aggression persisted between L. humile colonies despite maintenance under uniform rearing conditions, whereas Chen and Nonacs (2000) observed a decrease in L. humile intercolony aggression following 2 mo of laboratory rearing.…”

“…Shared dietary components, specifically hydrocarbons, for colonies displaying low intercolony genetic differentiation, may mask subtle inherent between-colony distinctions, thereby promoting fusion of adjacent colonies. Liang and Silverman (2000) and Silverman and Liang (2001) demonstrated the potential of prey hydrocarbons to alter nestmate recognition in the Argentine ant, with worker exposure to specific prey eliciting aggression from colony mates. Of the many different prey exposed to L. humile workers, contact with the brown-banded cockroach, Supella longipalpa, induced the highest level of intracolony aggression .…”