The effect of larval competition on development time and adult size in the seaweed fly, Coelopa frigida.

The effect of larval competition on adult size and egg to adult development time has been investigated in laboratory populations of the seaweed fly, Coelopa frigida. Increased larval density results in longer development times and smaller adults, suggesting a strong interference element to the competition. This may be due to a limiting rate of food supply rather than interactions between larvae. The relationship between development time and size suggests that both these characters are involved in control of the onset of pupation. C. frigida is polymorphic for an inversion on chromosome I. Differences in relative viability between the karyotypes are not related to the development time or size differences.