CHEMICAL SIGNALS AND NEST-BUILDING IN TWO SPECIES OF COLISA (PISCES, ANABANTIDAE)

Abstract

SUMMARY The following are the results of qualitative analysis of the visual and chemical signals and nest-building behaviour in Colisa lalia and C. labiosa under different experimental conditions: 1. Visual communication without any water contact between the test tank male and the female in the internal transparent container (Fig. 1 A); neither isospecific nor heterospecific pairs of either species showed reproductive behavioural changes. 2. Chemical communication through continuous water circulation between the female's external optically isolated glass container and the male's test tank (Fig. 1 B); an increase of aggressiveness and colour followed by nest-building by the male was induced. This test was performed on isospecific and heterospecific pairs of both species. 3. Actual contact (Fig. 1 E), isospecific pairs began their regular reproductive behaviour; heterospecific pairs displayed no reproductive behavioural changes. 4. Chemical communication with the test tank male in water exchange with a pair...