Interspecific communication in multispecies aggregation forming ithomiine butterflies (Ithomiinae)

Ithomiini (Nymphalidae), glasswing butterflies, form multispecies aggregations, a rare behavior among Lepidopterans.  Ithomiines are mimetic butterflies; within aggregations both multiple species and multiple mimicry groups are present.  Ithomiines visit aggregations for protection from predators and mate location.  Males display to females within aggregations, emitting pheromones derived from toxic plant secondary metabolites, pyrrolizidine alkaloids (PA). Some component(s) may serve as interspecific pheromones for aggregation formation. Species are constrained in pheromone suite because of cost of production, constraints of communication pathways and constraints of evolution.   Ithomiines use pheromones to communicate with conspecifics, heterospecifics and predators.  Although the vast majority of Ithomiine species acquire PAs as adults, basal Ithomiines get PAs from their larval host plant and do not participate in aggregations.  Ithomiines are presented with a suite of stimuli: conspecific pheromones, congeneric pheromones, pheromones from distantly related co-mimics and distantly related hetero-mimics and responses measured using an EAG GC-MS.  The species tested are Greta morgane (a clearwing), Mechanitis polymnia (a tiger) and Tithorea tarricina (a basal Ithomiine that acquires PAs as a larva and does not participate in aggregations).