might have led to this hybridization and the evolution of the dorippus tiger. From the colour pattern of this species, it can be assumed that the ancient lineage had no black apex on the forewings, as this characteristic is still absent in D. dorippus. The presumed subspecies cratippus most likely belongs to either the lesser wanderer or the dorippus tiger, but confirmation of its taxonomic status requires more research. In any case, these three species are closely related; their closest relatives, in turn, might be the soldier (D. eresimus) and queen (D. gilippus) butterflies. Several local forms have been described from Asia: Danaus chrysippus chrysippus f. alcippoides The upper hindwing is more or less very white; about half of the individuals have a second submarginal spot in the forewing. Occasionally found in South-East Asia, very rarely in India. Danaus chrysippus chrysippus f. gelderi The upper hindwing has white markings. Occasionally found on Sulawesi. Danaus chrysippus chrysippus f. bowringi The upper hindwing has a subapical band composed of somewhat larger spots, and an additional forewing spot as in f. alcippoides is always present. Found throughout the eastern parts of this subspecies' range. On the other hand, the plethora of named taxa from Africa are apparently F1 or F2 hybrids between the plain tiger subspecies (the contact zone of which is in the general area of Uganda) and/or D. dorippus: Danaus chrysippus × alcippoides is D. c. chrysippus × D. c. alcippus Danaus × transiens, Danaus × klugii, Danaus × albinus and Danaus × semialbinus are D. c. alcippus × D. dorippus Genomes When D. chrysippus was analyzed via a sample from Kampala, Uganda, it was found that the population was undergoing a significant level of evolutionary change. Three loci were examined, and genotypic frequency differences found at two of the three suggested that opposing selective forces, likely pertaining to Mullerian and Batesian mimicry, acting on males and females is contributing to a balanced polymorphism. Courtship and mating In addition to conferring protection from predators, pyrrolizidine alkaloids are necessary in the mating ritual of D. chrysippus. Male plain tigers use the alkaloids to synthesize pheromones which are stored in hair-pencils sheathed in alar organs, which are specialized scales on top of the hindwing. The hair-pencils are fanned out during courtship to release these pheromones, and this appears to be necessary for attracting females. Males deprived of pyrrolizidine alkaloids in their diet are