Larger Body Size at Metamorphosis Enhances Survival, Growth and Performance of Young Cane Toads (Rhinella marina)

Abstract

Body size at metamorphosis is a key trait in species (such as many anurans) with biphasic life-histories. Experimental studies have shown that metamorph size is highly plastic, depending upon larval density and environmental conditions (e.g. temperature, food supply, water quality, chemical cues from conspecifics, predators and competitors). To test the hypothesis that this developmental plasticity is adaptive, or to determine if inducing plasticity can be used to control an invasive species, we need to know whether or not a metamorphosing anuran’s body size influences its subsequent viability. For logistical reasons, there are few data on this topic under field conditions. We studied cane toads (Rhinella marina) within their invasive Australian range. Metamorph body size is highly plastic in this species, and our laboratory studies showed that larger metamorphs had better locomotor performance (both on land and in the water), and were more adept at catching and consuming prey. In mark-recapture trials in outdoor enclosures, larger body size enhanced metamorph survival and growth rate under some seasonal conditions. Larger metamorphs maintained their size advantage over smaller siblings for at least a month. Our data support the critical but rarely-tested assumption that all else being equal, larger body size at metamorphosis is likely to enhance an individual’s long term viability. Thus, manipulations to reduce body size at metamorphosis in cane toads may help to reduce the ecological impact of this invasive species.

Effects of hydroperiod on growth, development, survival and immune defences in a temperate amphibian

“…Small size at metamorphosis can have long‐term negative consequences. For example, juvenile size is often positively correlated with adult survival (Berven, ; Cabrera‐Guzmán et al, ). Larger juveniles often grow to be larger adults, and smaller juveniles can take longer to reach sexual maturity (Berven, ).…”

Relationship between Behavioral Thermoregulation and Physiological Function in Larval Stream Salamanders

“…In organisms with a biphasic life cycle (e.g., aquatic larval stage and terrestrial adult stage), body size at metamorphosis plays a key role in adult fitness (Werner, 1986) and is moderated by environmental factors including temperature (Alvarez and Nicieza, 2002;Walsh et al, 2008). Larger body size at metamorphosis can predict subsequent viability and fitness in amphibians (Smith, 1987;Berven, 1990;Altwegg and Reyer, 2003;Cabrera-Guzman et al, 2013). Therefore, larvae would be predicted to select temperatures that maximize growth rates to survive to metamorphose at the largest sizes.…”

Carry‐over Effects of Size at Metamorphosis in Red‐eyed Treefrogs: Higher Survival but Slower Growth of Larger Metamorphs

“…, Cabrera‐Guzman et al . ), compared to 10 of temperate species (see discussion). Life histories of tropical and temperate anurans often differ substantially (Morrison & Hero ), and we know almost nothing about metamorph behavior and growth in the wild anywhere (Relyea ).…”