1979] 
Alcock — Harpobittacus australis 
215 
away from the female’s mouthparts. Males appeared reluctant to 
extend their legs and so permit the female to feed. The time required 
for the female to draw the nuptial gift to her averaged 0.95 min with 
a maximum of 4.6 min (N = 11). When the male’s legs were fully 
extended the female could reach the prey with her mouthparts; she 
fed upon it for as little as 1 min to as much as 17.25 min. Imme¬ 
diately upon cessation of feeding the female disengaged from her 
partner and flew off. 
Selective Mate Choice by Females 
It seems likely that the probing of the prey by the female at the 
start of an encounter between the sexes permits the female to assess 
the nutritional/caloric value of the male’s present. Females offered 
small prey or insects that had been consumed by an earlier partner 
of the male frequently rejected the male outright, leaving before 
copulation could begin. If we consider the first observed reaction of 
a female to a prey offered by a male, copulation occurred only once 
in ten cases in which the prey was a tiny 3-4 mm mirid or beetle. In 
contrast, if the prey were estimated to be 6 mm or larger, mating 
occurred in 8 of 10 cases (x 2 = 7.3, P < .05). 
Five of twenty prey were offered to more than one (2-4) females 
in sequence. All five prey were 6 mm or larger. In one case, the prey 
was discarded by the male immediately after the second of two 
lengthy copulations. In the remaining four cases, the male dropped 
his gift only after it had been probed and rejected by a female, 
presumably because she found it an empty husk whose contents had 
been removed by earlier females. 
Thus the quality of the nuptial gift must be of a certain minimum 
standard if the female is to permit the male to copulate with her at 
all. In addition, Bornemissza (1966) felt that the size of the prey was 
related to the duration of copulation in H. australis. Table 1 shows 
that there is indeed a correlation between the estimated size of a 
prey and (1) the duration of the feeding phase of copulation and (2) 
the overall length of the copulation. Large food items evidently 
contain within them sufficient materials to keep the female occupied 
for some time, during which period the male presumably transfers 
sperm to her. 
Still more support for the hypothesis that the food value of the 
gift determines how long a female will feed on the prey and therefore 
how long she will copulate comes from comparisons of the response 
