none Host selection behaviour enables parasitoids to distinguish between suitable and unsuitable host species when encountered in a mixture. Previously observed variation among different geographic strains of the parasitoid Asobara tabida raised the question about how genetic variation is maintained for this character. Host selection behaviour of naive parasitoid females has a regular pattern; components of this pattern showed significantly high heritability estimates. The results provide evidence that not only host selection behaviour, but also the quickness of changing this behaviour is determined strongly by heritable factors.