Full-text - Norsk entomologisk forening

400 Torgeir EdlandTable I shows females grouped according to number of eggslaid. Mean egg number for 40 females in 1963 was 710, and for25 females in 1964, 875 eggs. The largest number for one female,was 1323 and 1470 eggs for 1963 and 1964 respectively, and themaximum for one night was 357 and 520 eggs per female for thetwo years. The females were collected from April 12 to May 9in 1963 and from April 7 to May 6 in 1964. It seems reasonable,therefore, to ask if the individuals ccllected at the later dateshad oviposited before being trapped. Fig. 2 indicates that eggsmay have been laid before the trapping of the insects. Accordingto the two regression equations given in the legend of Fig. 2,females collected in the early spring would be expected to oviposit1032 and 1218 eggs in 1963 and 1964 respectively.Six females kept outdoors at night temperatures ranging fromabout 4 to 15" C oviposited 865 -J= 159.4, while six females keptin the laboratory at about 20" C oviposited 805 5 99.4. Thisindicates no temperature influence on the total number oviposited,but, as shown in Fig. 3, the egg production has been acceleratedby placing the females under laboratory conditions ascompared with the colder outdoor condition. The influence oftemperature on the oviposition was also demonstrated in anexperiment in which five females were kept alternately in thelaboratory and outdoors every other night. Of the total of 5246eggs, 72.4 per cent were oviposited in the laboratory.Oviposition takes place after sunset and during the night.Females kept under continuous light did not oviposit and arenot, therefore, included in Table I. Kept in constant darkness,MEANNO. EGGSPER FEMALEDAYS AFTER TRAPPINGFig. 3. Mean number of eggs oviposited per night by six females keptin the laboratory (black bars), and six females kept oiitdoors (white bars).