Host plant selection in Plebejus argus (Linnaeus, 1758) and its mutualistic ant. The role of plant architecture (Lepidoptera: Lycaenidae)

In the Donana National Park the larvae of Plebejus argus (Linnaeus, 1758) feed on Halimium halimifolium L. Willk. and maintain a mutualistic relationship with the ant Lasius niger (Linnaeus, 1758), nesting on the base of these shrubs. The architecture of this plant has been analysed trying to assess if there are visual and structural characters selected by both the associated ants and butterflies for egg laying that enable a quick recognition of those with a greater probability of occupancy. We also analyse whether the behaviour of selection of ants matches in areas of high and low density of nests. The results show that ants choose higher and more isolated plants both in areas of high and low density of nests. The selection of the butterfly for egg laying partially matches that of the ant, although isolation of the plant has no significance for butterflies. It is possible to identify egg-carrying target plants prior to scrub clearings, trying to mitigate the collateral effects that this management measure has on these species.