Experimental evaluation of agonistic behaviour, chemical communication, spacing, and intersexual associations of the Eastern Red-backed Salamander (Plethodon cinereus) near its northern range limit

Abstract

Territorial behaviour is the use of aggression and advertisement in the defense of a fixed area. In the Eastern Red-backed Salamander (Plethodon cinereus (Green, 1818)), territoriality is prevalent in Virginia, USA, near the southern extent of its range, but few studies have examined whether northern populations exhibit territorial behaviour. We tested for some prerequisites of territorial behaviour in P. cinereus at the northern extent its range, near North Bay, Ontario, Canada. In laboratory trials, we found that adult male P. cinereus exhibited a modest degree of aggression, and intruding salamanders attempted to escape the experimental chamber more often than residents. We also found that P. cinereus were able to differentiate between familiar and unfamiliar substrates, suggesting pheromonal communication and a potential for territorial advertisement. However, while male–female pairs were common at six sampling sites during the mating season, adult salamanders consistently exhibited a random spatial distribution during the nonmating season. Our study suggests that local P. cinereus exhibit low-level aggression but may not defend fixed areas. One possibility is that P. cinereus may generally not benefit from territorial behaviour in cooler climates, as evapotranspiration rates will be lower and foraging activity less restricted compared with more southern climates.