Differences in population parameters of twoTribolium castaneum strains in environments of different shapes

Summary

• (1) Survival and duration of development of twoTribolium castaneum strains were not the same when reared in environments of different shapes under the same external conditions.

• (2) Thebb strain survived better in jars than vials. The ++ strain survived better in vials than in jars of type 3.

• (3) Both strains (as well as their hybrid (+b)) developed faster in vials (type 1) than in shallow jars (type 2). Both strains developed faster in jars of type 3 than in vials, at the low density. At the high density, the strains reacted differently: ++ developed faster in vials, butbb developed faster in jars.

• (4) Cultures of “selected” strains followed the population trends they exhibited in the selection experiments from which they came.

• (5) In both densities and in all environments, mean individual weight of ++ adults was always higher then that ofbb, suggesting that this character is, at least in part, genetically determined.

• (6) The differences in survival and developmental period in environments of different shapes may be due to microclimatic differences between environments and to changes produced in them by the developing immatures.