220 
Psyche 
[December 
Table 6 — Effect of nutrition on receptivity following parturition 
in N. cinerea 
Diet 
Number used 
and percent 
mating 
Days after 
parturition to 
mate (Mean ± S.E.) 
During gestation 
after parturition 
N 
% 
lab chow r 
lab chow* 
60 
85 
0.7 ± 0.1 
lab chow 
starved 
105 
76 
0.7 ± 0.1 
starved§ 
lab chow* 
60 
98 
2.8 ± 0.2ff 
starved§ 
starved 
128 
23 
3.5 ± 0.4 
* Females that were fed were exposed to males and food <24 hr. after 
parturition. 
§ Given 9-10 days to mate after parturition. 
H The oocytes of these females were 0.94 ± 0.02 mm. long measured <24 
hr. after mating. 
large at the time the females gave birth. Therefore, one would 
expect that inanition during gestation, and subsequent feeding fol- 
lowing parturition would affect female receptivity. The results of 
experiments to determine the effect of nutrition on receptivity in 
N. cinerea are shown in table 6 and figure 14. A high percentage 
(85 and 76%) that were fed during gestation, and were then 
starved or fed, mated again. In marked contrast, only 23% became 
receptive again if they were starved during and after gestation; in 
other experiments, as high as 40% of similarly starved females were 
receptive (fig. 16). It should be noted that the females were starved 
in groups; some females died and were partly or completely eaten 
during the night before they could be removed from the containers. 
This may have increased the percentage of females that became 
receptive again. However, in spite of this source of error, it is 
evident that starvation during gestation markedly reduced the num- 
ber of females that regained their receptivity, provided the females 
were not fed after parturition. 
N. cinerea females that are fed during gestation and become 
receptive after parturition, usually mate within a day after giving 
birth; this is true whether or not the females are fed after parturi- 
tion (table 6). However, females which are starved during gestation 
and are then exposed to males and food after parturition become 
receptive more slowly; 80% mated within 4 days after giving birth 
whereas a comparable percentage of females fed during gestation 
did so <24 hr. after parturition (fig. 14). Only 23% of the 
females starved during gestation and after parturition mated within 
a 9-10 day period and these averaged 3.5 ± 0.4 days to mate 
(table 6). When, after 9-10 days, the remaining females were 
