Big number of butterflies invaded Kyiv on June 4, which became topic #1 for Kyivans and immediately flooded social media with photos. This quantity of insects appeared due to the early and warm spring which led them to pupate almost simultaneously, Vallery Korneev explained, Hromadske reported.
"The kells were developing during a week, until the wings and legs formed. And immediately after a heavy rain, all the cocoons dehisced and all the imagoes (adult insects) appeared simultaneously this morning, Korneev explained.
Usually the caterpillars appear in May-June in small groups in their nests, on the branches of some kinds of willow and aspen. The kells are developing for 12 days, however this time they all turned into butterflies simultaneously.
The scientist also added that the butterflies that invaded Ukraine’s capital these days are called black-and-tan large tortoiseshell. It’s caterpillars feed on willows and poplars.