Acta Phytopath. Entomol. Hung. (2009) 44: 111-117.

Éva Lauber and Béla Darvas

Increased mortality of isolated first instar larvae of Inachis io (Lepidoptera)

The European peacock butterfly, Inachis io Linnaeus is one of those lepidopteran species whose larvae stay together after hatching. Larvae usually aggregate in batches of hundreds. Isolated first instar larvae, although spin or feed to some extent, spend most of their time apparently waiting for a signal yet unknown for continuation, and finally end up dying until the second moult. In our experiments the mortality of isolated larvae varied significantly from 25% to 75%, indicating that loneliness induces a kind of death signal of unknown origin in first instar larvae of I. io.