Does temperature and oxygen affect duration of intramarsupial development and juvenile growth in the terrestrial isopod Porcellioscaber (Crustacea, Malacostraca)?

Terézia Horváthová,Jan Kozłowski,Paulina Kramarz,Andrzej Antol,Anna Labecka,Ulf Bauchinger,Marcin Czarnoleski

doi:10.3897/zookeys.515.9353

Abstract

According to the temperature-size rule (TSR), ectotherms developing under cold conditions experience slower growth as juveniles but reach a larger size at maturity. Whether temperature alone causes this phenomenon is unknown, but oxygen limitation can play a role in the temperature-size relationship. Oxygen may become limited under warm conditions when the resulting higher metabolism creates a greater demand for oxygen, especially in larger individuals. We examined the independent effects of oxygen concentration (10% and 22% O2) and temperature (15 °C and 22 °C) on duration of ontogenic development, which takes place within the maternal brood pouch (marsupium), and juvenile growth in the terrestrial isopod common rough woodlouse (Porcellio scaber). Individuals inside the marsupium undergo the change from the aqueous to the gaseous environment. Under hypoxia, woodlice hatched from the marsupium sooner, but their subsequent growth was not affected by the level of oxygen. Marsupial development and juvenile growth were almost three times slower at low temperature, and marsupial development was longer in larger females but only in the cold treatment. These results show that temperature and oxygen are important ecological factors affecting developmental time and that the strength of the effect likely depends on the availability of oxygen in the environment.

Highlights

One of the most widespread patterns in biology is the temperature-size rule (TSR), which predicts slower growth and larger adult size for ectotherms growing in cold environments (Atkinson 1994)
The duration of intramarsupial development in warm conditions was half that in the cold temperature (23 vs. 58 days; Fig. 1), but female post-parturial mass and temperature had an interactive effect on the duration of marsupial development (p < 0.001; Table 1, Fig. 2), which caused apparent lack of significant effect of temperature (Table 1)
We found that the duration of intramarsupial development of woodlice depended on temperature and oxygen level, with the latter effect being small, but statistically significant

Summary

Introduction

One of the most widespread patterns in biology is the temperature-size rule (TSR), which predicts slower growth and larger adult size for ectotherms growing in cold environments (Atkinson 1994). Because the high metabolic oxygen demands of large individuals increase more rapidly at high temperatures (Verberk et al 2011; Woods 1999), oxygen limitation is expected to be stronger under warm conditions (Chapelle and Peck 1999; Verberk and Atkinson 2013) and at later stages of ontogeny (Aguilar-Alberola and Mesquita-Joanes 2014) These different size- and temperature-dependent oxygen requirements of ectotherms may favour a smaller body size in warm environments and a larger size in cold ones (Atkinson et al 2006; Frazier et al 2001; Walczynska et al in press)

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