-159- 



some application to field situations, it is adapted primarily for use 

 in experimental laboratory studies. 2) An additional column "t x " was 

 inserted between l x (number surviving at the beginning of the age 

 interval) and d x f (factors responsible for death). The time spent in 

 age interval x is recorded in this column. This should not be 

 confused with "T x " of Southwood (1978), which represents the total 

 number of animal x age units beyond age x. This addition should 

 provide a more comprhensive picture of the life history and dynamics 

 of a colony population. 



In Table 3-7, the l x for eggs is based strictly on the number of 

 eggs laid, and does not account for irreplaceable loss due to egg 

 retention by females or potential eggs lost due to nonfeeding or 

 unmated females. The l x values for larvae and pupae represent the 

 number that survived the previous stage. 



As the life table shows, the greatest loss (d x ) occurs in the egg 

 stage (64%) due to infertility, excessive moisture, dessication and 

 mold. This is rather high when compared with the corresponding figure 

 of 4.4% for a colony of _Lu_. 1 ongipa 1 pi s (Ki 1 1 ick-Kendrick et a!., 

 1977). The 2nd most important loss is lst-instar larvae, the most 

 delicate instar. About 5% of the larvae will die as 1st intars, five- 

 fold more than in all other instars combined. Most deaths of 1st 

 instars probably result from entrapment in moisture (usually in 

 condensation droplets on the sides of the vial), entrapment in mold, 

 or from dessication. The later instars are less susceptable to 

 entrapment in moisture and mold, although some still occurs in the 2nd 

 instar. The extent to which cannibalism and fungal infections 

 contribute to mortality in 2nd through 4th instars is unknown. In 



