1964 ] Roth — Reproduction in Cockroaches 219 
unfertilized. Six (10%) of 61 females mated to males that had 
mated previously within an hour aborted unfertilized eggs; thirteen 
(81%) of 16 females that were mated to males that had mated 
twice within a few hours aborted their oothecae. Subsequent recep- 
tivity, following parturition of females that were mated to virgin 
males or males that mated twice consecutively, was the same. Of 
132 females mated to virgin males, 1 1 7 (89%) were receptive after 
parturition; 52 (93%) of 56 females that had mated males, which 
mated twice consecutively, were receptive; only 3 females (the 
others aborted unfertilized eggs) mated to males that mated 3 
times consecutively, gave birth to normal sized litters, and these 
females mated again following parturition. Consecutive matings may 
affect female oviposition behavior because no sperm, or an insufficient 
amount of sperm enter the spermathecae from spermatophores formed 
during the second and third matings. However, if sperm are present 
and the eggs are fertilized, the mating behavior of females, following 
parturition, is the same whether they are mated to virgin males or 
males that mated 2 or 3 times consecutively; the spermatophores 
produced by the latter males presumably had fewer sperm. 
Effect of starvation on receptivity of females 
Thirty-six females were given food and water for 24 hr. only on 
the sixteenth day of pregnancy. After parturition (gestation aver- 
aged 39.0 ± 0.6 days) they were exposed to males and lab chow. 
Thirty-four (94%) eventually mated and their oocytes were 
0.96 ± 0.0 1 mm. long <24 hr. after mating. At parturition, the 
oocytes of females starved during pregnancy are smaller than those 
in females that feed during gestation. In starved females, presumably 
the corpora allata do not become reactivated in late gestation, as 
they do in fed individuals (cf. fig. 1). It was shown earlier that 
after parturition receptivity could be correlated with the size of the 
oocytes; unreceptive females were those whose oocytes were relatively 
Table 5 — Receptivity of females, mated to castrated males, which oviposited 
and whose oothecae were removed after various periods of time 
Age (days) of 
oothecae when 
removed from uteri 
Days after removal 
of oothecae females 
mated 
(Mean ± S. E.) 
Oocytes (mm.) 
(Mean ± S. E.)* 
N 
16 - 18 
6.3 ± 0.7 
1.21 ± 0.06 
5 
19 - 21 
3.6 ± 0.4 
1.04 ± 0.02 
10 
33,34 
2.5 ± 0.5 
1.02 ± 0.07 
2 
* <24 hr. after mating. 
