G. J. Snowball. 
-4‘> 
Chapman (1931) divides animal successions into passive and active 
according to the part played by the animals concerned. Though less so than 
that in carrion, the succession in cow dung is of the active type since the 
insects do affect their environment. Volume for volume cow dung supports 
a smaller poj3ulation tlian carrion. This is due to the less powerful odour 
which is the primary attracting stimulus, the less nutritious nature of the 
dung itself , and in the case of flies the comparatively short time during which 
it is a suitable medium for oviposition owing to the early formation of a more 
or less impervious crust. All these factors result in a less well-defined succes- 
sion tlian occurs in carrion. 
As has been indicated previously, there is a correlation between the type 
of insect in carrion and that in dung, many species being common to both 
habitats. Nevertheless, each substance has its own characteristic insects 
physiologically adapted to it with only a casual association with the other. 
Jllowflies visit cow dung but their life history is bound up with carrion. In 
the same way, Cercyons are sometimes found on carrion yet they are character- 
istic cow dung insects. 
Both in carrion and cow dung are insects which either have a wide dis- 
tribution themselves, e.gr., Aphodius lividus, Cercyon haemorrhoidalis, or 
have closely allied species in other parts of the world, e.g.. Sepsis plebeia 
This is to be expected, as neither carrion nor faecal matter is subject to geo- 
graphical variation. 
10. THE ECONOMIC IMPORTANCE OF INSECTS FOUND IN COW 
DUNG. 
The primary sheep blowflies Callipliora australis Boisd, C. nociva Hardy, 
and Lucilia cuprina Wied., have only a casual association with various species 
of Sarcophaga, are secondary sheep blowflies, and some of these breed in cow 
dung, though the importance of this material to the flies as a breeding sub- 
stance is not known. Musca domestica Linn, prefers other breeding nidi, 
and no evidence has been seen that Stomoxys calcitrans Linn., which occurs 
in numbers in Perth, ever frequents dung at Crawley. Research in various 
parts of the world has showm that cow dung is among the least favoured of 
the breeding media of this fly. 
Musca vetustissima Walker is a common pest in Perth on man and cattle. 
Cow dung is an important source of the fly here, especially that dropped in 
swampy situations. Rhynchoniydaea carmata Stein and the species of Helina 
associated with cow dung at Crawley are not domestic insects, nor have they, 
as far as is known, any habits rendering them objectionable to man. Muscina 
stabidans Fallen is not abundant at Crawley. In any event, cow dung is 
only one of a large number of breeding materials utilised by this fly. 
In South Australia and Tasmania, two Aphodiines, which normally feed 
on dung, have come under notice because their lavae have been found damag- 
ing pastures and lawns (Swan, 1934 ; Evans, 1941). These are Aphodius 
howittiy Hope, and A. tasynaniae^ Hope, neither of which has been collected at 
Crawley. No complaints have been received by the Department of Agri- 
culture against any local species in this connection. 
When L. J. Newman, in 1929, succeeded in rearing Lyperosia exigua de 
Mcij., the Buffalo fly on cow dung under midwinter conditions in Perth, with- 
out the application of artificial heat, it was feared that this pest might be 
introduced in the dairying regions in the southern part of the State. Pre- 
cautions against this possibility in the form of sprajdng cattle before they 
left North-West jiorts were introduced (Tcoj^, 1931). The fly has not been 
reported in the South-West, nor has any sign of it been seen at Crawley. 
