While we hear a lot about moths in the world of invasive species, we very rarely hear anything about butterflies. So it was with interest that I read this Pest Report from the Phytosanitary Alert System announcing that the Lime Swallowtail (Papilio demoleus) was discovered last June in Puerto Rico (.pdf). The Lime Swallowtail, native to Asia and Africa, is a pest of...you guessed it...citrus species, and it appears to be following citrus crops around the world. Puerto Rico is the second confirmed occurrence of this species in the New World, the first being in the Dominican Republic back in 2004 (.pdf). The main concern of the arrival of this butterfly in the New World is the potential threat to citrus crops (not surprisingly, Florida is concerned), but the 2004 article above does note that there are New World Papilio butterflies that could feel the heat of competition, and there is some concern that the caterpillars will feed on wild plants in the Rutaceae (citrus family).