1984] 
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197 
as Johnson (1982) suggested, that this could potentially provide 
males with a basis for discriminating the most reproductively fit 
females. Males capable of assessing a cue to female fitness could 
“decide” whether to remain with a particular female or search for 
another. This would explain our findings of large females most 
often in pairs. Such a tactic could be even more feasible in insect 
populations which occur in high densities. The resulting high 
encounter rates would mean less time spent searching for more 
suitable mates. 
This hypothesis assumes that larger eggs enhance the success of 
resultant offspring (e.g., through increased nutrient provisions or 
greater competitive ability of larvae). Such advantages are contro- 
versial, but the rather limited data do yield some support. 
Relationships between egg size and offspring success in insects have 
been addressed by Capinera (1979 and references therein), Richards 
and Myers (1980) and Barbosa, et al. (1981). 
Discrimination of mates by males has been shown in several 
species in which males are contributing relatively large amounts of 
paternal care or other benefits (for insect examples see Thornhill 
and Alcock 1983). Perhaps more significant for this discussion are 
the findings of mate discrimination by males of noninvesting species 
(Loiselle; 1982; Verrel 1982; Hatziolos, M. E. and R. L. Caldwell 
1983; references in Thornhill and Alcock 1983; Johnson and 
Hubbell, unpublished). Although some of the latter examples are 
laboratory experiments, the fact that the apparently adaptive 
behavior is exhibited suggests that selection under natural circum- 
stances must be occurring at significant levels. 
Several recent papers have reported overrepresentations of larger 
females within mating populations of insects. Such biases, based on 
either size or weight, have been found in beetles (McCauley and 
Wade 1978, Johnson 1982 and McLain 1982), pierid butterflies 
(Marshall 1982), ambush bugs (Dodson and Marshall 1984) and 
tephritid flies (Dodson, submitted). It would be interesting to 
determine the relationship between female body size and egg size in 
all such species in light of a male mate discrimination hypothesis. 
McCauley and Wade (1978) showed that mating male and female 
soldier beetles, Chaulignathus pennsvlvanicus, were heavier than 
nonmating males and females based on dry weights. They con- 
sidered dry weight to be an index of body size and suggested larger 
