Apparent Dear‐enemy Phenomenon and Environment‐based Recognition Cues in the Ant Leptothorax nylanderi

Abstract

Inter‐ and intraspecific competition was investigated in ants of the myrmicine genus leptothorax in a deciduous woodland near Würzburg, Germany. The most common species, A. (Myrafant) nylanderi, lives in rotting pine, oak, and elder sticks and may locally reach densities of 10 nests per m2. In the studied sites, only a small fraction of colonies were polydomous, i.e. single colonies typically did not inhabit several nest sites. The home ranges of nylanderi colonies overlap the ranges of other conspecific colonies and colonies of other species, especially L. (s.str.) gredleri. Foragers from different colonies encountering one another in the field back off without exhibiting strong aggression, suggesting that colonies do not defend absolute foraging territories. In laboratory experiments, the frequency and severity of agonistic interactions among workers from different colonies, all living in pine sticks, increased significantly with the distance between their nests. Workers from colonies nesting in different types of wood exhibited significantly more aggression. Experiments in which we transferred colonies from pine sticks into artificial pine or oak nests corroborate the hypothesis that nesting material strongly influences colony odour in L. nylanderi. The evolutionary significance of this apparent dear‐enemy phenomenon is discussed.

The parasite's long arm: a tapeworm parasite induces behavioural changes in uninfected group members of its social host

“…acorns, sticks) in the leaf litter of deciduous forests throughout Europe (e.g. [27]). Parasite pressure in the local population is high, as approximately 30% of the colonies contain one or more tapeworm-infected individuals [26].…”

Seasonal nestmate recognition in the polydomous ant Plagiolepis pygmaea

“…These recognition cues may have a genetic basis, they may be derived from the environment (e.g. diet or nesting material), or they may originate from both sources (Wilson 1971;Jutsum et al 1979;Carlin & Hölldobler 1986;Gamboa et al 1986;Obin & Vander Meer 1988;Crosland 1989;Hölldobler & Wilson 1990;Le Moli et al 1992;Heinze et al 1996;Liang & Silverman 2000). Aggression assays are useful to investigate nestmate recognition and its genetic and/or environmental origin in social insects (Gamboa et al 1991;Roulston et al 2003).…”

How do cuticular hydrocarbons evolve? Physiological constraints and climatic and biotic selection pressures act on a complex functional trait

“…Moreover, ant colonies from populations with social parasites show more diverse CHC profiles, suggesting that parasites select for higher cue diversity [17,18]. Besides, there are non-heritable CHC differences owing to environmental factors like food [19,20], host species [21], nest site material [22], short-term acclimation to climatic conditions [23,24] or changes in social status [25]. Except for sexual dimorphism [7], however, these intraspecific differences are largely restricted to quantitative variation of the same set of hydrocarbons.…”