Responses of juvenile terrestrial salamanders to introduced (Lithobius forficatus) and native centipedes (Scolopocryptops sexspinosus)

Abstract

When introduced species invade ecosystems, alterations in community structure can emerge from the competitive and predatory interactions that occur between introduced and native guild members. Because a number of recent studies have shown that large predatory invertebrates can both compete with and prey on small vertebrates and because introductions of non-native species may play a role in amphibian declines, the effects of introduced centipedes Lithobius forficatus and native centipedes Scolopocryptops sexspinosus on juveniles of the red-backed salamander Plethodon cinereus were examined. In laboratory arenas, juvenile salamanders exhibited submissive behaviour in response to the odours of both species of centipede. There were no significant differences in salamander response to the two centipede odour treatments, but compared to controls, juveniles of P. cinereus spent significantly more time in escape and in a flattened submissive posture when presented with native centipede odours. Despite significant size differences between centipedes and juvenile salamanders, no predation of salamanders by either species of centipede occurred in any pairings. Juveniles exhibited more chemosensory behaviour towards native centipedes and towards their odours and exhibited marked reductions in aggressive posturing when centipedes were present. Field and laboratory data suggest that juveniles of P. cinereus and centipedes were negatively associated. In laboratory trials, the native centipede excluded juvenile salamanders from cover objects and we found fewer instances of co-occurrence in the field than expected. These studies are the first to examine the behavioural interactions between juveniles of P. cinereus and invertebrate predators, one introduced and one native, of eastern deciduous forest-floor food webs.

Invasive Asian earthworms of the genus Amynthas alter microhabitat use by terrestrial salamanders

“…For example, behavioural indices have been used to determine if a salamander displays submissive or dominant agonistic behaviours in response to competitor, mate, predator, and prey cues (Jaeger 1984). Previous investigations have shown that P. cinereus responds aggressively to invertebrate guild members, such as centipedes (Hickerson et al 2004;Anthony et al 2007) and beetles (Gall et al 2003). It is possible that aggressive behaviour toward earthworms could be occurring if salamanders mistake worms for guild members.…”

Innate and Learned Predator Recognition Mediated by Chemical Signals in Eurycea nana

“…If prey exhibiting innate predator recognition are unable to acquire recognition of novel predatory stimuli, they may not respond adaptively to non‐native predatory threats (Kiesecker & Blaustein 1997; Pearl et al. 2003; Anthony et al. 2007).…”

“…Determining the role of experience in predator recognition is especially important for native prey in habitats where predators have been introduced. If prey exhibiting innate predator recognition are unable to acquire recognition of novel predatory stimuli, they may not respond adaptively to nonnative predatory threats (Kiesecker & Blaustein 1997;Pearl et al 2003;Anthony et al 2007). This has been described as a primary cause of native amphibian population declines and extinctions in some habitats where non-native predators have been introduced (Knapp & Matthews 2000;Adams et al 2001;Pilliod & Peterson 2001;Kats & Ferrer 2003).…”

Competition and Intraguild Predation Between Beetles, Pterostichus stygicus (Coleoptera: Carabidae) and Centipedes, Scolopocryptops sexspinosus (Scolopemdromorpha: Scolopocryptopidae)

“…We used the methodology of Anthony et al (2007) to assess the ability of S. sexspinosus and P. stygicus to displace one another in a structurally simple environment. We constructed arenas with low (dry portion of the arena), intermediate (dampened filter paper covering a portion of the arena floor), and high-quality microhabitats (dampened filter paper and space beneath artificial cover; Fig.…”

“…We placed either a single centipede, a single beetle, or one individual of each species into arenas, and after 24 h, the locations of individuals in nine interspecific pairs were compared to locations of nine solitary individuals of each species. In the absence of interference, individuals are expected to gain access to high-quality habitat (Anthony et al 2007). In interspecific trials, we predicted that, if competition were occurring for high-quality space, competitively dominant individuals would gain access to the highest quality microhabitat in laboratory arenas.…”