CHAPTER 1
 GENERAL INTRODUCTION

 Nearly every biological process depends to some extent on nutrition. Ingestion, digestion,

and nutrient absorption determine an animal's capacity for maintenance, growth, reproduction,

and survival. An individual's success thus depends on its capacity to extract and utilize nutrients

from its food. However, many organisms experience variation in food availability throughout

their lifetimes (Plotz et al. 1991, Boggs and Ross 1993, Carey et al. 2002a), and evolutionary

adaptation to these fluctuations is critical to species survival. Fluctuations in food availability can

result from climatic or seasonal dynamics of food sources and spatial or temporal heterogeneity

of nutrient distribution (Dagg 1977, Smith and Ballinger 1994, Forman 1995, Arnekleiv et al.

2006, Schradin and Pillay 2006). Periods of "feast" and "famine" result in correspondingly fast

and slow periods of growth, development, and reproduction (Ballinger 1977, Calbet and Alcaraz

1997, Kitaysky 1999, Morey and Reznick 2000). Such developmental plasticity is common to

many species (Stearns 1982, Smith-Gill 1983, Schew and Ricklefs 1998), especially those in

stochastic environments (Lochmiller et al. 2000).

 One adaptation to cycles of low and high nutrient availability is compensatory growth

(CG). This phenomenon manifests itself as a period of growth faster than that demonstrated by

consistently well nourished conspecifics of the same age (Fig. 1-1) and can result in comparable

body sizes for individuals with very different dietary histories (Broekhuizen et al. 1994, Metcalfe

and Monaghan 2001). Compensatory growth presumably allows organisms to mitigate

size-specific mortality risks and developmental time constraints induced by periodic nutritional

stress (Arendt 1997). This growth pattern is typically effected by hyperphagia (increased feed

intake), improved food conversion efficiency (defined as growth per unit of food consumed), or

both (Miglavs and Jobling 1989, Ali et al. 2003). Compensatory growth has been documented in