Orientation and emigration of larval and juvenile amphibians: selected topics and hypotheses

Lukas Landler

doi:10.1163/15685381-bja10081

Abstract

Most amphibians have a complex life cycle with an aquatic larval and an adult (semi-) terrestrial stage. However, studies concerning spatial behaviour and orientation mainly focus on either the aquatic larvae or the adult animals on land. Consequently, behavioural changes that happen during metamorphosis and the consequences for emigration and population distribution are less understood. This paper aims to summarize the knowledge concerning specific topics of early amphibian life history stages and proposes several testable hypotheses within the following fields of research: larval and juvenile orientation, influences of environmental and genetic factors on juvenile emigration, their habitat choice later in life as well as population biology. I argue that studying larval and juvenile amphibian spatial behaviour is an understudied field of research, however, could considerably improve our understanding of amphibian ecology.

Highlights

Amphibians are among the most threatened taxa in the world, about 40% of the species in this group are at risk of extinction (Stuart et al, 2004; Vié, Hilton-Taylor, and Stuart, 2009; Bishop et al, 2012)
Behavioural changes that happen during metamorphosis and the consequences for emigration and population distribution are less understood
This paper aims to summarize the knowledge concerning specific topics of early amphibian life history stages and proposes several testable hypotheses within the following fields of research: larval and juvenile orientation, influences of environmental and genetic factors on juvenile emigration, their habitat choice later in life as well as population biology

Summary

Introduction

Amphibians are among the most threatened taxa in the world, about 40% of the species in this group are at risk of extinction (Stuart et al, 2004; Vié, Hilton-Taylor, and Stuart, 2009; Bishop et al, 2012). Several amphibian taxa, especially in the neotropics, do not follow this pattern and are not considered in here Some deviations of such pattern (i.e., no free swimming larvae) can be related to different levels of parental care taking which are widespread and evolved many times in the amphibian evolutionary history (Furness and Capellini, 2019; Schulte et al, 2020). Most amphibians in temperate regions can be categorized as having a complex life cycle with an aquatic (free swimming) larval development and a (semi-) terrestrial adult stage. Inherent to such life cycles are breeding migrations, which in many cases require amphibians to navigate surprisingly long distances. My goal is to connect the existing evidence on these issues with hypotheses and research questions regarding amphibian spatial and population ecology

Larval and juvenile orientation in their natal habitat

Influence of natal habitat cues on philopatry

Findings

Proposed research questions and concluding remarks