Simulated predation pressure in Pelobates cultripes tadpoles modulates morphology at the metamorphic stage

Abstract

Studies on the impacts of variation of biotic interactions at key life cycle stages are crucial to understand the interface between ecological and developmental processes. Predators exert a major impact on prey fitness. Although direct consumption entails the greatest effect, predators can affect prey by means of other mechanisms. For instance, injuries inflicted by failed predation attempts can jeopardize prey fitness, even beyond the short-term. In anuran tadpoles, failed predation typically results in partial tail loss, which is known to reduce swimming speed. However, the potential consequences of tadpole partial tail loss after metamorphosis remain understudied. Because tail materials could be important in conforming metamorph body, we assess the effects of tadpole partial tail loss on metamorph body size in Iberian spadefoot toads Pelobates cultripes. We clipped 55% tail length of pre-tail-resorption stage anesthetized tadpoles, and compared their body size as metamorphs with anesthetized and non-anesthetized non-tail-clipped controls. Also, we tested whether tail length correlated with metamorph body size of individuals of the control groups. Tail-clipped tadpoles produced smaller metamorphs than both controls (the bdy size of metamorphs from both controls was similar), which could incur costs in mid-term survival or time to first reproduction. This effect could be particularly important in areas with introduced predators, if autochthonous tadpoles lack defenses against them. Results suggest that materials resorbed from tadpole tail tissues might be reallocated into metamorph body, according to the negative effect of shorter tails in a correlational analysis, and clipped tails in an experimental test, on metamorph body size.

Failed predator attacks have detrimental effects on antipredatory capabilities through developmental plasticity in Pelobates cultripes toads

“…Nevertheless, in a previous study we detected negative effects of partial tail loss in tadpoles of Iberian spadefoot toad ( Pelobates cultripes ) on metamorph body condition (Zamora‐Camacho, Cortés‐Manzaneque, & Aragón, ). Further negative consequences of partial tail loss on metamorphs could also involve locomotor performance, particularly if hindlimbs, which are primarily responsible for locomotion in jumping anurans (Astley, ; Petrovic, Vikov, & Kolarov, ), are affected.…”

“…First, we performed planned comparison tests on two one‐way ANOVAs to test the effects of treatment on HL/SVL and on maximum jump distance, respectively. Also, to examine to which extent phenotypic traits of this and the previous study (Zamora‐Camacho et al, ) are linked we performed correlations between corpulence and maximum jump distance or HL/SVL, and maximum jump distance and HL/SVL. Moreover, we repeated all the analyses with average jump distance (see Supporting Information).…”

“…Tadpoles were randomly allotted to one of three groups. Tadpoles assigned to the experimental group were anaesthetized in a clove oil solution (450 mg/L of water; Mitchell, Riggs, Singleton, Diaz‐Figueroa, & Hale, ; Zamora‐Camacho et al, ) until they lost movement and righting reflex as a response to a gentle touch. Tadpoles were removed from the solution before they lost respiratory reflex.…”

“…In the other control group, tadpoles were neither anaesthetized nor tail‐clipped. 55% was the maximum percentage of tail clip that was not followed by death of individuals in a preliminary test (Zamora‐Camacho et al, ). Tadpoles of P. cultripes regenerate an even greater percentage of tail lost in 10–15 days (Nunes et al, ).…”

“…Little is known about reallocation of tail materials after resorption during late metamorphosis in anurans. However, previous findings that morphology is affected by partial tail loss suggest that tail matter could be important in building metamorph body (Zamora‐Camacho et al, ). In this work, we assess whether partial tail loss in tadpoles affects metamorph limb morphology and jump performance.…”