The Relevance of Observations from Experimental Populations to Natural Populations with Regard to the Role of Social Factors in Adult Reproduction

Abstract

If data collected from the laboratory are to be used to decipher mechanisms of interaction between the environment and the individual which are then to be applied to an understanding of environment/animal interaction in the wild, the degree to which the laboratory environment can be compared with the field environment must first be established. This comparison may be made by considering the two situations in terms of their spatial construction and biological composition. The latter is composed of the numbers and type of animals used. Spatially the laboratory arrangement is very different from the field situation on two main counts. The first is the obvious one of confinement, i.e. the inability of the experimental animal to emigrate from the area. Under field conditions increases in numbers are almost inevitably followed by movement from areas of high density. The second is the inability in the laboratory to duplicate the spatial complexity of the field environment. This can be avoided by the use of populations which are confined in field areas, such as has been done in Australia in rabbit population studies (Myers and Poole, 1959; Mykytowycz, 1959). It can be of considerable importance in its effects on the frequency of individual contact between the animals in the experimental area. If the environment is not complex the experimental animals will be unable to get away from other individuals, which will in turn affect the social arrangements in the pen or cage. The lack of environmental complexity will also affect the location of feeding and watering facilities, which will in turn have effects on the social development of the laboratory colony. There is also evidence from studies such as those of Myers (1966) and Bailey (1966) that the total amount of space available will have an effect independently of the density. This may mean that there are even more qualities of the spatial environment which cannot be duplicated in the laboratory. Laboratory and penned experiments are thus conducted in environmental conditions which can never be considered as absolutely comparable with field conditions.