Predator-induced morphological changes in an amphibian: predation by dragonflies affects tadpole shape and color

Abstract

Predator-induced defenses are well studied in plants and invertebrate animals, but have only recently been recognized in vertebrates. Gray treefrog (Hylachrysoscelis) tadpoles reared with predatory dragonfly (Aeshnaumbrosa) larvae differ in shape and color from tadpoles reared in the absence of dragonflies. By exposing tadpoles to tail damage and the non-lethal presence of starved and fed dragonflies, we determined that these phenotypic differences are induced by non-contact cues present when dragonflies prey on Hyla. The induced changes in shape are in the direction that tends to increase swimming speed; thus, the induced morphology may help tadpoles evade predators. Altering morphology in response to predators is likely to influence interactions with other species in the community as well.

Stress hormones mediate predator-induced phenotypic plasticity in amphibian tadpoles

“…); the no predator treatments received empty cages. Predators were fed approximately 0.3 g of live R. sylvatica tadpoles three times per week to produce predator chemical cue [26,37]; empty predator cages in control tanks were similarly manipulated to simulate disturbance caused by feeding. On day 25 of the experiment, four tadpoles were collected from each of the experimental tanks, pooled into two samples, and immediately flash frozen for later analysis of baseline wholebody CORT content by extraction and radioimmunoassay (RIA; described below).…”

Predator-induced stress makes the pesticide carbaryl more deadly to gray treefrog tadpoles ( Hyla versicolor )

“…Predator treatments consisted of either a caged larval salamander (Ambystoma maculatum) or an empty cage (250-ml plastic cups covered with fiberglass window screening). Caged predators emit chemical cues that induce antipredator responses in their prey without allowing the predators to kill the target animals (29)(30)(31).…”

Locomotion and survival of two sympatric larval anurans, Bufo gargarizans (Anura: Bufonidae) and Rana zhenhaiensis (Anura: Ranidae), after partial tail loss

“…4) After accounting for 8.2 mm mean body length, the mean tail length of R. zhenhaiensis tadpoles (16.5 mm) was greater than of B. gargarizans tadpoles (12.2 mm) ( Table I). An enlarged tail may increase the interest of aquatic predators, resulting in a higher frequency of tail damage in tadpoles with larger tails (SMITH & VAN BUSKIRK 1995, MCCOLLUM & LEIMBERGER 1997, BLAIR & WASSERSUG 2000, VAN BUSKIRK et al 2004. 5) The body and tail (hereafter body size) of B. gargarizans tadpoles were smaller than of R. zhenhaiensis tadpoles ( Table I).…”