The growth of restricted populations of Lasioderma serricorne (F.) (Coleoptera, Anobiidae)

Abstract

Two types of population history shown by Lasioderma serricorne (F.) are described, one when the food was renewed at regular intervals, the other when there was no food renewal. Initially, both of these populations increased together to a high level, the former continuing at this level until the observations were discontinued, the latter declining and eventually becoming extinct. Stage-specific properties, which relate the numbers in each stage to those a unit of time previously and which are functions of the survival, developmental and fecundity rates, were estimated for each type of population; they are compared as between the two types and with the corresponding properties of a population given effectively unlimited space and food. It is shown that the effect of the limiting conditions produced a decrease in survival, developmental and fecundity rates. From this, together with other evidence, it appears that food shortage, not space shortage, was the primary cause. After the initial increase in numbers, the stage-specific properties shown by the species in both populations imply that there was a regular oscillation in the developmental, survival or fecundity rates, which would result in corresponding fluctuations in numbers.