The timing of energy allocation to reproduction in an important group of marine consumers.

Blaine D Griffen,Heather M Patterson

doi:10.1371/journal.pone.0199043

Abstract

Organisms may energetically finance reproductive effort using energy stored prior to the reproductive period (termed capital breeders) or using energy acquired during the reproductive period (termed income breeders). The specific strategy used has implications for population dynamics as well as for the response to environmental variation. Crabs and other crustaceans have generally been assumed to be capital breeders. Here I demonstrate an experimental procedure used to determine whether crabs are capable of using an income breeding strategy. I then examine data from several published studies from a range of crab species across a broad phylogenetic spectrum that conducted similar experiments to look for evidence of income breeding strategy. I show that income breeding does occur in crabs, but that it appears to be taxon-specific. In particular, I show that income breeding occurs in two species from the family Portunidae, but fail to find evidence for income breeding in other taxa examined. This finding has a range of implications for this ecologically and economically important group of consumers, including implications for their response to human-induced environmental change, their response to fishing pressure, and best practices for aquaculture. The implications of breeding strategy in crabs likely depends on phylogeny (morphology) and ecology, both of which influence the space available for energy storage inside the carapace.

Highlights

The energetics of individual organisms play an important role in ecological processes, determining, for instance, where organisms can survive [1], the allocation of time to different activities [2], the rate at which organisms grow [3], the timing of important life-history processes [4], and the timing and level of reproductive performance [5]
Some store energy used in reproduction prior to the start of the reproductive process, termed capital breeders, while others finance reproduction using energy gained throughout the reproductive process, termed income breeders [6,7]
The residual analyses indicated that for both C. maenas (t = 3.10, P = 0.004, Fig 1A) and C. sapidus (t = 9.04, P < 0.001, Fig 1D), the residual ovary size increased with residual food consumption, supporting the use of an income breeding strategy

Summary

Introduction

The energetics of individual organisms play an important role in ecological processes, determining, for instance, where organisms can survive [1], the allocation of time to different activities [2], the rate at which organisms grow [3], the timing of important life-history processes [4], and the timing and level of reproductive performance [5]. Some store energy used in reproduction prior to the start of the reproductive process, termed capital breeders, while others finance reproduction using energy gained throughout the reproductive process, termed income breeders [6,7]. A species’ location along the capital-income continuum has important implications for population growth and dynamics. The timing of energy storage for reproduction has been linked to population cycling and explosive population growth [12] and to the occurrence of carry-over effects as individuals move from one location (feeding area) to another (breeding area) [13]

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Conclusion