Bell Miners: What Kind of Farmers Are They?

Abstract

The hypothesis that Bell Miners Manorina melanophrys Meliphagidae when foraging on psyllids selectively consume the sugary cover of the insect (lerp) leaving the nymph behind (the 'farming' hypothesis) was tested, using data from the gizzard contents of 122 birds. The 'farming' hypothesis predicts that: (a) the gizzards of Bell Miners should contain relatively more lerps than psyllid nymphs; (b) they should have a larger lerps/nymphs ratio than gizzards of other, presumably 'non-farming', bird species; and (c) the highest values of lerps/nymphs should be found in adult male Bell Miners during the non-breeding season. None of the above predictions was supported. This preliminary work fails to produce strong evidence for the 'farming' hypothesis.