1975] 
Waldorf — Sinella coeca 
36 
gradual decline until 6 hours prior to the next ecdysis when no 
males exhibited this behavior. 
Neither the number of bouts of cleaning nor the lengths of these 
differed in reproductive as compared with nonreproductive males. 
The averages, considering all grooming, are presented in Table 2. 
Similarly, there are no differences in antennal grooming as a func- 
tion of reproductive condition. 
The average frequencies of grooming through the instars are 
illustrated in figure 2. The patterns in reproductive and nonrepro- 
ductive males are essentially the same. Both groom most frequently 
12-18 hours after ecdysis. Thereafter a lower rate is more or less 
constant until 70-75% of the instar has elapsed. This declines to 
near zero before ecdysis. Of the 1 1 pharate males observed in 
previous experiments, only one performed one antennal cleaning. 
Table 2. The average number of bouts of grooming in 5 min. and 
their average duration in male Sinella coeca in the 
reproductive and nonreproductive instars. 
No. of bouts Length of bouts 
per animal (in sec) 
x n SD x n SD 
Reproductive instar 1.3 10 .518 25.93 98 15.86 
Nonreproductive instar 1.3 10 .441 23.43 49 10.48 
Discussion 
The pattern of alternate reproductive and nonreproductive instars 
observed in Sinella coeca characterizes both sexes of Sinella curviseta 
(Waldorf, 1971) and some members of the genera Orchesella, 
Tomocerus and Isotoma ( Poggendoff , 1956; Mayer, 1957 > Joosse 
and Veltkamp, 1970). Similarly, reproductive instars are longer in 
males of S. curviseta (Waldorf, 1971) and Orchesella cincta L. 
(Poggendorf, 1956) than nonreproductive ones. Although not 
enough data are available to draw a conclusion, this pattern might 
apply generally within the family Entomobryidae. 
The experimental observations of isolated males provided estimates 
of the frequency of spontaneous grooming. The data indicate that 
the rate of spontaneous grooming does not vary between types of 
instar but does vary within instars. 
Fluctuations in response to female (or male) associates might be 
superimposed on the basic pattern (fig. 2). An example of the effect 
