Larval feeding behaviour and myrimecophily of the Brenton blue, Orachrysops niobe (Trimen) (Lepidoptera: Lycaenidae)

Abstract

*[The larval feeding behavior & myrmecophily of the Brenton Blue Orachrysops niobe, an endangered polyommatine butterfly from Knysna in South Africa, were investigated by field observations & captive larval rearing. Third & fourth instar larvae & pupae were found in association with Camponotus baynei ants on the host plant rootstock. Ant colonies in viewable artificial C. baynei nests were sited near host plants bearing multiple O. niobe eggs, but no larvae were taken into the nests. Cannibalism was observed between larvae raised in captivity on cut host plant. A third instar captive larva was enclosed with a potted host plant connected to a similar artificial ant nest. The larva disappeared & was later found feeding on the depleted plant rootstock, tended by the ants. This behavior was confirmed by field observations. O. niobe's ant association is inferred to be obligate. Leguminous Indigofera host plants have amino acid enriched rootstocks, which may have pre-adapted the larval digestive system to a cannibalistic or carnivorous lifestyle. Larval growth characteristics are used to compare African polyommatine genera & Orachrysops is intermediate between the facultative myrmecophilous genera & the predaceous/parasitic Lepidochrysops species.]