Introduction of Glanville fritillary leads to emergence of three new species on to Baltic Sea island
When caterpillars of a beautiful butterfly were introduced on to the tiny island of Sottunga in the Åland archipelago, scientists hoped to study how the emerging butterflies would disperse across the landscape.
But researchers did not realise that their introduction of the Glanville fritillary (Melitaea cinxia) led to the emergence of three other species on to the Baltic Sea island, which sprang out of the butterfly like Russian dolls.
Some of the caterpillars contained a parasitic wasp, Hyposoter horticola, which bursts from the caterpillar before it can pupate and become a butterfly.
Living inside some of these small wasps was another even tinier, rarer parasite, a “hyperparasitoid” wasp known as Mesochorus cf. stigmaticus. It kills the parasitic wasp around the same time as the wasp kills the caterpillar, and emerges 10 days later from the caterpillar’s carcass.
Also along for the ride was a bacterium that is carried by the female H. horticola wasps and transmitted to her offspring. By some unknown mechanism, Wolbachia pipientis increases the susceptibility of the parasitic wasp to being taken over by the tiny parasitic wasp M. stigmaticus, which can only live on the H. horticola wasp.
Like those Russian dolls crossed with the Xenomorph from Alien.