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females could be preferentially mating with larger (and presumably 
more fit) males by physically resisting mating attempts by all males 
and escaping the smaller ones. They further postulated that larger 
females might be “somewhat more receptive than small females”. 
However, except for the suggestion that receptivity might be related 
to egg development, they did not account for the paucity of small 
females in the mating population. Woodhead (1981) offered what 
appeared to be a more parsimonious explanation. She found that 
mating females had larger eggs than “rejecting” females and 
proposed that heavier female soldier beetles were more often found 
mating because they were more reproductively mature and therefore 
more receptive to mating. Woodhead (1981) did not discuss her 
choice of eggs for measurement. She did state that soldier beetles 
“mature eggs in groups” and so we assume that all primary oocytes 
were measured, including many not yet fully-yolked. Even if this 
were the case, however, her measurements are also consistent with 
the hypothesis that females differ in ultimate egg size and not just 
developmental stage. 
In many insects, oocytes are in various stages of development 
within the ovaries throughout most of a female’s adult life. This 
makes comparative measures of all eggs virtually impossible 
because of the miniscule size of the youngest oocytes. For valid 
comparisons between females, age classes of eggs must be de- 
lineated. Typically, fully-yolked eggs are chosen because they are 
easily defined, relatively easy to distinguish (although not always), 
and supposedly will not get any larger. We avoided this problem by 
measuring only chorionated eggs, i.e., eggs that are fully grown with 
their “shells” encasing them. Thus, we have demonstrated variation 
in egg sizes between females which are independent of sexual 
maturity and apparently dependent on female size. 
In summary, we have shown that P.fasciata males, when paired 
with females, aggressively fend off intruding males and that larger 
females produce larger eggs. Previous work (Dodson and Marshall 
1984) revealed that males were more often paired with larger rather 
than small females in a natural population. All of these factors are 
consistent with the hypothesis that given some choice, males will 
preferentially guard mates which provide a higher reproductive 
potential. 
