Flowerhead selection for oviposition by females of the sympatric butterflyspecies Maculinea teleius and M nausithous (Lepidoptera : Lycaenidae)

The butterfly species Maculinea teleius Bergstrasser 1779 and M nausithous Bergstrasser 1779 often inhabit the same meadows and lay eggs on flowerhead s of the same host plant, Sanguisorba officinalis (Great Burnet). The flowe rhead preferences of ovipositing females [FF] of both species were studied and found to be different. FF of M teleius oviposited on younger flowerhead s which were closer to the ground, shorter, with fewer flowers and usually with none or at most one other conspecific egg already present. FF of M nau sithous chose older flowerheads which were taller, larger, and with more eg gs of each of both species. These differences caused partial segregation of the eggs of the 2 species, as the host inflorescences were used by FF of o ne species when young and by the others when more mature. It appears that p reviously laid eggs are not recognised. FF searching for oviposition sites apparently select flowerheads visually according to their developmental sta ge.