Dear Enemy Phenomenon in the Ant Ectatomma brunneum (Formicidae: Ectatomminae): Chemical Signals Mediate Intraspecific Agressive Interactions

Abstract

The integrity of ant colonies depends exclusively on social relationships between their individuals, especially the ability of communication between group members, which is mainly mediated through chemical signals. Another important feature of ant behavior is territory defense, since they need to gather large amounts of food to feed their larvae, males and breeding females. Thereby, ants might display behavioral strategies to defend their territories from intruders. Here we investigated whether Ectatomma brunneum displays the Dear Enemy Phenomenon, what is the relationship between Cuticular Hydrocarbon composition and levels of aggression during their intraspecific interactions and which compounds and/or classes of compounds might be the most important to modulate the level of aggression. To test our hypothesis, we evaluated the levels of aggression through behavioral observations during interactions between 23 pairs of colonies nested in two distinct sites at varied distances. Then, we analyzed the cuticular chemical profile of the individuals involved in the interactions, and compared these results with the levels of aggression displayed between colonies tested. The results allow us to confirm our hypothesis that the DEP occurs in E. brunneum. The higher tolerance between closer colonies can be explained due to their kinship level in addition to sharing the same microhabitats. The results also showed there are significant differences in CHCs profiles, especially between colonies nested at relatively greater distances, and it is likely that differences in content of some branched alkanes are the most important to establish these differences and, therefore, the levels of aggression during the interactions.

Magnetosensibility and Magnetic Properties of Ectatomma brunneun Smith, F. 1858 Ants

“…In normal conditions, under the influence of the geomagnetic field, we found higher levels of aggression among E. brunneum ants (scores for before in Fig 3A ) whose nests were further apart in more than 100 m (Fig 2). This finding means that these ants are tolerant to individuals from nests in a radius of 100 m. Pereira et al (2019) showed that E. brunneum colonies are more tolerant to ants from nearest the nanoparticles are mainly in the superparamagnetic state, and in the head, the nanoparticles are mainly single domains and superparamagnetic nanoparticles in the blocked state. Magnetometry studies done in other ants have shown that all parts of the ant body are magnetic (Wajnberg et al, 2010), but the abdomen and the head show different magnetic properties.…”

A glândula metapleural de formigas (Hymenoptera: Formicidae) com diferentes estilos de vida: morfologia e volatilômica

“…brunneum (Pereira et al, 2019). Dodecano presente apenas em P. clavata é relatado pela primeira vez em formigas, sendo encontrado em extratos da casca de planta medicinal nativa da Ásia Symplocos crataegoides (Govindarajan et al 2016).…”