A growth/mortality trade-off in larval salamanders and the coexistence of intraguild predators and prey

Abstract

Behavioral and morphological traits often influence a key trade-off between resource acquisition and vulnerability to predation, and understanding trait differences between species can provide critical insight into their interactions with other species and their distributions. Such an approach should enhance our understanding of the criteria for coexistence between species that can interact through both competition and predation (i.e. intraguild predators and prey). I conducted a common garden experiment that revealed strong differences between three guild members (larval salamanders Ambystoma laterale, A. maculatum, and A. tigrinum) in behavior, morphology, and growth in the presence and absence of a shared top predator (the larval dragonfly Anax longipes). All three species also reduced their activity and modified their tail fin depth, tail muscle length, and body length in response to non-lethal Anax. Species that act as intraguild predators were more active and could grow faster than their intraguild prey species, but they also suffered higher mortality in laboratory predation trials with Anax. I also used survey data from natural communities to compare the distribution of Ambystoma species between ponds differing in abiotic characteristics and predatory invertebrate assemblages. An intraguild prey species ( A. maculatum) was found more reliably, occurred at higher densities, and was more likely to persist late into the larval period in ponds with more diverse invertebrate predator assemblages. Taken together, these results indicate that top predators such as Anax may play an important role in influencing intraguild interactions among Ambystoma and ultimately their local distribution patterns.

Effects of habitat complexity, prey type, and abundance on intraguild predation between larval odonates

“…Intraguild predation can have a profound influence on population dynamics and the composition and stability of communities (Mylius et al, 2001;Arim & Marquet, 2004;Yurewicz, 2004). Understanding the factors that influence the frequency and intensity of intraguild predation remains an important objective.…”

Intra-specific variability of hindlimb length in the palmate newt: an indicator of population isolation induced by habitat fragmentation?

“…In amphibians, favourable habitats such as forest area [19,20] and proximity to water bodies often indicate for a high abundance of newts, leading to increased intra-specific competition for resource access, which could cause morphological variations in larval amphibians [19][20][21][22]. Given that HLL is associated with dispersal capacities [6], forest areas hence provide suitable conditions for newts, which leads to individuals with a greater propensity for dispersal [23].…”

“…Despite the strong relationships between environmental features and HLL that we detected here, others factors can also drive such morphological variations that could be, therefore, subject to natural selection. Pond topology and/or hydroperiod [24] could have strong influences of metacommunity structure by causing variation in population density, and hence shape variability in larval amphibians [21,22]. Complementary studies are still needed to disentangle the potential effect of those last variables on leg length.…”

Socially facilitated antipredator behavior by ringed salamanders (Ambystoma annulatum)

“…voraciously consumed A. macrodactylum larvae in laboratory tests, and Stofer and White (2004) found that when larval A. tigrinum were raised with dragonfly nymphs (Anax junius) they developed deeper tails, likely to increase escape locomotion. Behaviorally, three species of larval Ambystoma (A. laterale, A. maculatum, and A. tigrinum) showed decreased activity in the presence of caged dragonfly nymphs (Yurewicz 2004), but the sensory modality used for recognition (visual or chemical) is not known.…”