BODY-SIZE AND FEEDING SPECIFICITY - MACROLEPIDOPTERA IN BRITAIN

Within a geographic assemblage, large-bodied species of macrolepidopte ran moths tend, on average, to be less host-specific than small-bodied . Five possible explanations for this pattern are identified, based re spectively on (i) phylogenetic relationships between species, (ii) lat itudinal gradients in body size and feeding specificity, (iii) the rel ationship between range size and body size, (iv) larger body size as a buffer from environmental variation, and (v) the relationship between endophagous host associations and small body size. These mechanisms a re tested using data for British macrolepidoptera and also evaluated u sing evidence from the literature at large. Although some of their ass umptions are found to be justified, there is no significant support fo r any single mechanism. This lack of evidence for previously proposed mechanisms is discussed in the light of a recently proposed alternativ e explanation which combines theories of host quality and host defence mechanisms. (C) 1998 The Linnean Society of London.