Meet The Blind Insect That Can Fly! A New Troglobiotic Orthoclad (Diptera, Chironomidae) Has Been Found In Trojama Cave, Croatia

Meet The Blind Insect That Can Fly! A New Troglobiotic Orthoclad (Diptera, Chironomidae) Has Been Found In Trojama Cave, Croatia

Several terrestrial animals make themselves adaptable to cave life and are generally named troglophiles, and troglobionts. Troglobionts are considered that they inhabit caves by spending their entire lifespan inside of them. There are more than twenty-one thousand terrestrial cave worldwide which are troglobionts and almost all of them prefer to live in the ground.


Despite the fact that several Diptera insect species were recorded to have been appeared in caves, few of them have been recorded to be actual cave species, as more of them are occasional guests of the caves and are considered troglophiles.  Nevertheless, some of these insects were evolved, and have adapted morphologically and physiologically to be able to live as troglobiotic species do.

Despite that there were many pronouncements of such evolved species around the world and more particularly in Africa, most of these insects reside in the caves only in the first few hundred meters from the cave’s entrance.  During expeditions made during 2013 in the Lukina Jama cave, which is situated in the Trojama cave system in Velebit Mountain, Croatia, several female insects of a pale chironomid that belong to the Orthocladiinae subfamily of insects were found and collected in chamber of a cave which is 980 meters below the surface of Earth.

This new species was observed by the researchers between the 800th and 980th  meters’ depth. Although it is difficult to ascertain whether the species is present only in Lukina Jama cave, it is reported that is unlikely to be found elsewhere, or even deeper in the cave because of it uninhabitable conditions. The chamber where the species was found contains several habitats for the species, including dry walls, hygropetric places where water seeps from its walls, small sediment stream and a small stand with standing water. All these inside the chamber are remarkably perfect for such insects to grow and live, as these are capable of being potential habitats for insects that are at an immature stage.

The species found is recorded to be of medium size, with its wing length to range between 1.8 to 2.2 milimeters. Its head is strongly hairy without or with reduced ommatidia. They have broad wings with excavated anal lobes. They possess very long legs for the size of their body and they have very-well developed genitals, which makes them capable for reproduction.

Thus, there is a unique combination in this species of strongly reduced eyes and large wings.  such a combination is exceptional in troglobiotic species and is an indicator that the species is capable of flying very slow or hover over when there is no light inside the cave. Their long legs are stated that they might serve as their feeling sensors, as they are providing assistance to the insect to maintain its balance when they are stretched forward when they are flying.

Researchers cannot place the species within any systematically family based on its morphological characters. This particularly because this unique animal is known for only having females at the moment and because it has adapted to such extend within the cave life that is impossible having not known everything about it to place it accurately within any of the families already categorised.


If the species is endemic only in that particular cave, then great care should be placed when examining the species in order not to reduce its population or make it vulnerable to extinction.