Seasonal changes in characteristics of cattle dung as a resource for an insect in southwestern Australia

Abstract

The value of cattle dung as a food resource for the bush fly Musca vetustissima (Walker) in the winter rainfall agricultural region of southwestern Australia was assessed by bioassay in the laboratory. The size (headwicJth) of adult females was measured from flies reared on different samples of dung. Variation in size correlated with seasonal patterns of pasture growth, larger flies being produced during the growing season from autumn to spring. Size declined with senescence of annual pastures in late spring and early summer, occurring later in southern areas where the growing season was longer. After pasture senescence, dung from shorter growing season areas usually produced larger flies, apparently a result of the inverse relationship between digestibility of feed and length of growing season. Dung from irrigated perennial pastures never prochued flies as large as that from anmuil pastures but generally high values were sustained during summer. Grazing of cereal stubble and feeding of hay in annual pasture areas during summer usually caused some increase in fly size. A spontaneous resurgence in the size of flies often occurred several weeks after pasture senescence and was attributed to more thorough digestion as a result of reduced intake of less palatable dry pasture.

The effect of seasonal changes in cattle dung on egg production by two species of dung beetles (Coleoptera: Scarabaeidae) in south-western Australia

“…Dung collected at Dardanup in November 1982 appeared more favourable than in November 1981, and that collected from Dandaragan in January 1982 appeared more favourable than in January 1981. This variability also occurs in the size of M. vetustissima adults reared on dung from pasture in south-western Australia (Matthiessen & Hayles, 1983). When it is considered how many factors are involved in the responses measured, it is not surprising that variability is common.…”

“…These changes are reflected by the size of adult bush flies, Musca vetustissima Walker, reared from the dung and to some extent their egg to adult survival (Greenham, 1972;Sands & Hughes, 1976;Matthiessen & Hayles, 1983;Matthiessen et al, 1984). Changes in the nutritive value of cattle dung also influences the egg production of scarabaeine dung beetles (TyndaleBiscoe et al, 1981;Macqueen et al, in press) and the size of emerging adult beetles (Lee & Peng, 1982).…”

“…The size of M. vetustissima adults is greatest when they are reared from dung collected during the growing season in spring; it declines when annual plants become senescent in early summer, and becomes somewhat variable during the summer and autumn due to changes in the digestibility of the feed and its composition through supplementary feeding (Matthiessen & Hayles, 1983;Matthiessen et al, 1984). Flies reared on dung from irrigated perennial pastures are larger than flies bred on dung from dry annual pastures in the same areas in summer and autumn (Matthiessen & Hayles, 1983).…”

“…Flies reared on dung from irrigated perennial pastures are larger than flies bred on dung from dry annual pastures in the same areas in summer and autumn (Matthiessen & Hayles, 1983).…”

Stages of bush fly, Musca vetustissima (Diptera: Muscidae), killed by scarabaeine dung beetles (Coleoptera: Scarabaeidae) in unfavourable cattle dung

“…Rate of oviposition by Onthophagus binodis and Onitis alexis is high in favourable dung and low in unfavourable dung (Ridsdill-Smith, 1986). Fewer M. vetustissima oviposit on unfavourable than favourable dung (Ridsdill-Smith & Hayles, 1989), but their main response is that adults emerging from larvae that have fed on unfavourable dung are smaller than those from favourable dung (Matthiessen & Hayles, 1983;Ridsdill-Smith & Hayles, 1989;Sands & Hughes, 1987). In the laboratory, the same number of Onthophagus binodis kill more M. vetustissima in unfavourable dung than in favourable dung (Ridsdill-Smith et ah, 1986).…”