Sperm precedence was investigated in the 2-spot ladybird, Ada/ia bipunctata by utilizing a di-allelic colour marker gene. Non-melanic (homozygous recessive) virgin females were mated once with a non-melanic male and after subsequent laying of fertile eggs they were mated with a melanic male of known genotype. Frequencies of colour morphs in the offspring provided evidence for almost complete second male sperm precedence, although the data from certain matings do not completely exclude the possibility of first male sperm precedence. The results are discussed in the light of the hypothesis of thermal melanism.