The influence of adult size and protein diet on the human-oriented behaviour of the bush fly, Musca vetustissima Walker (Diptera: Muscidae)

Abstract

AbstractAdults of Musca vetustissima Walker that were caught when attracted to humans in the field responded positively in a later test when a hand was inserted in a cage, both in terms of proportion responding and time spent on the hand. Flies with a similar adult diet, whether of culture origin or the first-generation offspring of field-caught flies, responded similarly to the hand in the cage provided they were of similar size. A larger proportion of small flies than of large ones came to the hand, and stayed for longer periods. Large protein-deprived and dung-fed (suboptimal protein) flies had a nuisance value between 28 and 35 times as great as large blood-fed flies, while small blood-fed flies had a nuisance value 18 times as great. The nuisance value of small protein-deprived and dung-fed flies was between 61 and 67 times as great. Residence period on the hand increased with time in large protein-deprived flies but not in flies in the other categories tested. Few flies responded to the hand during the first 15 day-degrees C post eclosion, or when gravid or nearly gravid; the most responsive flies were in ovarian stages 0B, 1, 2 and 3. The implications of these results are discussed in terms of the fly nuisance levels experienced in south-eastern Australia.