Interference with learning in pipevine swallowtail butterflies: behavioural constraint or possible adaptation?

Ovipositing Battus philenor learned host leaf shape when Aristolochia host species were presented singly in outdoor enclosure arrays. When species were presented together, however, learning of one leaf shape interfered with learning of another. For two of three Aristolochia species presented singly, females found hosts at higher rates overall than when all host species were presented together. Host-finding rates increased with successive encounters when those two species were presented singly, but not when all three species were presented together. Improvement in host-finding with experience was associated only weakly with increases in oviposition rate. Females that find hosts at higher rates will be more selective about the plants on which they deposit eggs, placing more progeny on plants on which they are more likely to survive. -from Author