Heritability of selectively advantageous foraging behaviour in a small passerine
ID: 92037 • Letter: H
Question
Heritability of selectively advantageous foraging behaviour in a small passerine WILLIAM C. LEMON of Zoology. University of reras, Aurnn. Tx 7s712 usA Summary I measured the heritability of foraging patch choice in aLaboratory population orzebra finches (Taerrionysia which provided four different rates of energy gain. Use of foraging patch with a high rate of enerzy gan has been shown to confer a selective advanta zebra in a similar experimental In this population of zebra finches there was a amount of variation in patch choice behaviour within and among individuals. I de ermined that foraging patch was phenotypically labile trait with degree of stereotypy or repeatability. much lower than those typically recorded for morpho traits. The mating behaviour of zebra finches required that heritability be determined from a mother-offspring regression, which showed that narrow sense heritability of foraging patch choice was approximately 0.346. This heritability was significan y different than zero, as was heritability when it was mited by repeata to 0,246. Foraging patch choice, a behaviour that has a demonstrated fitness consequence. h a heritable component in this laboratory population of zebra finches Keywords: foraging behaviour: heritability; repeatability: Taeniopygia: zebra fin Introduction Foraging behaviour has been studied intensively during the last few decades using optimality (Pyke et al., 1977: Krebs et al., 1983: Schoener. 198ny. Models invoking this conceptual basis predict how animals should adjust their foraging behaviour to the types and distributions of available prey and many are based on the assumption that natural selection favours animals that maximize their net rate of energy gain while foraging (Schoener, 1971; Pu am, 1974; Charnov 1976). In this type of study there is an implicit assumption that differences in the net rate of energy gain result in differential reproductive success or fitness. It is also assumed that due to the selective advantages of energetically efficient foraging behaviour, foraging behaviour will evolve toward an optimum. The theory requires that in order for a foraging behaviour to respond to selection, there must be heritable variation in the behaviour (Pyke et al.. 1977; Kamil and Sargent, 1980; Pyke, 1984) Few studies have been published to date on the possible role of heritability in determining foraging behaviour (Kamil and Sargent, 1 Schoener, 1987), perhaps because theory predicts that foraging should be a variable behaviour, changing frequently in response to changes in the availability of food (Schoener, 1987). However, increasing interest in the genetic basis of behavioural traits has led to studies of the heritability of foraging behaviour in several organisms such as snakes (Arnold 1980, 198ia, b), mice (Gray, 1980). cave fish 19so), (Wallin, 1988) and spiders (Hedrick and Riechert, 1989) Present address: Arizona Research Laboratories, Division of Neu University of Arizona. Tucson. Az 8572 0269-7653 1993 Chapman & HallExplanation / Answer
1) There was a considerable variation in foraging behavior among individuals in this population of zebra finches. The mating behavior of zebra finches showed that narrow sense heritability of foraging patch choice was 0.346. This was significantly different from zero, as was heritability when it was limited by repeatability to 0.246. Therefore foraging choice behavior has demonstrated a fitness component and had a heritable component. Presence of these components will surely give rise to variations. So,there was a considerable degree of varaition in foraging behavior among zebra finches.