Insects ENG

The insects are an old and presently most widespread animal group. The oldest ones have been documented in Devonian; during Carboniferous and Permian saw great development and expansion of it, including arachnids, mayflies, cockroaches, caddisflies, beetles, etc. Thanks to a high level of oxygen in the atmosphere, which enabled arthropods to develop more efficient breathing through spiracles, and also thanks to the absence of bigger predators, some insects reached gigantic size. The biggest known terrestrial arthropod ever was arthropleura. These relatives of present-day centipedes were over 2.5 metres long and weighed around 50 kilograms. They lived in contemporary swampy forests and were herbivores. The biggest flying insects also developed in the same period. They were dragonflies of genus Meganeura and Meganeuropsis. Their wingspan was up to 75 centimetres and they weighed up to 0.5 kilogram. Being active predators, they hunted other invertebrates and possibly also small vertebrates. The majority of other arthropods were also significantly bigger than their present-day relatives during Late Paleozoic. 

The fossils rarely yield insects, since their bodies commonly did not have any solid parts. The finds are fixed in fine-grained sediments or amber (fossilized tree resin), most commonly featuring wings, which are the most durable body parts of insects. In rare cases, the Krkonoše Piedmont Basin has yielded wings of cockroaches, mostly preserved in tuff (volcanic ash); the finds were discovered around Nová Paka and Lomnice nad Popelkou.