T. Birkemoe et Hp. Leinaas, Effects of temperature on the development of an arctic Collembola (Hypogastrura tullbergi), FUNCT ECOL, 14(6), 2000, pp. 693-700
1. Embryonic development, juvenile moulting and growth rates, and maximum s
ize of the arctic collembolan Hypogastrura tullbergi were investigated at 5
, 10 and 15 degreesC in laboratory experiments. The embryonic development w
as also investigated at 21 degreesC.
2. The lower temperature threshold of the embryonic development (to) was -1
.3 degreesC, possibly reflecting a slight cold adaptation. The temperature
of maximum development rate exceeded 21 degreesC.
3. Instar duration rate was linearly related to temperature. Growth per ins
tar, however, was thermally dependent, giving an overall non-linear correla
tion between growth and temperature. This emphasizes the importance of stud
ying growth and moulting as separate processes in Collembola.
4. Development of genital area (number of hairs) over succeeding instars wa
s affected by the temperature, suggesting that a higher proportion of indiv
iduals reached the adult stage in an earlier instar at 15 than at 10 degree
sC.
5. Contrary to the general pattern in ectotherms of increasing size at lowe
r temperatures, adult H. tullbergi reached a larger maximum size at 15 than
at 10 degreesC.
6. No aspects of postembryonic development in H. tullbergi showed any signs
of cold adaptation, probably because it is more important to be able to ef
ficiently utilize high temperatures that frequently occur in the microhabit
at during sunny periods in summer.