A Consideration of the Insect Population Associated 
WITH Cow Dung at Crawley, W.A. 
229 
The actual information on the life history of A. lividus is slight and much 
of it must be conjectured. This is due to the slow growth of the larvae and the 
difficulty of handling them imder laboratory conditions. Eggs and larvae of 
Scarabs are numerous in cow dung at Crawley, but strangely enough most of 
them are those of Proctophanes sculptus Hope, the adults of w’hich are much 
fewer in number than those of A. lividits. 
Scarab eggs are common in fourth stage dung from February to August. 
Eggs have been kept in the laboratory up to 11 days before liatching. This 
represents less than the minimum egg period since none were actually col- 
lected immediately after laying. Altho\igh Scarab larvae are adapted to the 
firm, rusty-brown dung of the fourth stage, they sometimes occur in the moister, 
■fresher dung of the third. 
The life history period from the egg to the emergence of the adult was 
foimd to be as short as 45 days during March (average temperature 20*6° C.) 
and April (18*6° C.), 1941. Three larvae which pupated in April emerged in 
May after pupal periods of fourteen to sixteen days. It seems that under cer- 
tain circumstances the period of development from the egg to the adult can be 
considerably shorter than that of A. tasmaniae, which is approximately one 
year (Swan. 1934). Lindquist (1935) estimated the life history period of A. 
lividus to be 25 to 45 days at Uvalde, U.S.A. under laboratory conditions. 
Pupation usually occurs in the sand below the dung., the pupa (PI. 1, 
Fig. 4) being unprotected by any cocoon structure. 
It is probable that the species breeds in other media besides cow dung, 
•since the larvae seen were very few compared with the large number of adults. 
Aphodius insignior, Blkb, 
Blackburn (1904) erected this species from specimens taken near the Swan 
River, and Schmidt (1922) only gives Western Australia as its area of distribu- 
tion. 
No representatives were found at Katanning in August, 1941. At Crawley 
they show a remarkable seasonal distribution. Up till June, 4, 1941, no speci- 
mens had been collected since August, 1940. On that date one specimen was 
discovered in a second stage cow dung. On 16th June, following rain, myriads 
appeared, swarming in fresh dung near tlie Biology Department. They prac- 
tically excluded all other beetles and burrow'ed even into the most liquid cakes. 
The large numbers were maintained until the end of July when a decline set in. 
By 30th August they liad again disappeared. 
This appearance in large numbers suggests that A. insignior has a life 
history similar to 'that of A. tasmaniae j which has an annual emergence of adults 
over a short period of the year. As no immature stages of A. insignior have so 
far been found, this must remain conjectural for the present. 
The species exhibits a marked preference for fresli, greenish dung on which 
it feeds freely. The beetles are exceedingly tolerant of moist conditions, which 
gives them a considerable advantage over other insects in colonising cakes. 
When inside the dung or on it they habitually associate in pairs. Hanging 
on to the prothorax of the female with its forelegs, the male is carried round on 
her back and requires considerable persuasion to dismount. This habit is 
no doubt a prelude to mating, though actual copulation has not been observed . 
A. insignior rarely remains on the dung beyond the second stage. 
