Hygrobia

Hygrobia hermanni

The wet mud bugs or float ( Hygrobiidae ) represent a very small family of beetles dar. far, a total of only six known species within the same genus. One is in Europe and North Africa, one in western China and four in Australia. The phylogenetic relationship of the family within the Adephaga is not yet fully clarified.

Features

The beetles are about 8.5 to 10 millimeters in length and have an oval, streamlined body with head stretched, which, as the pronotum is narrower. This is short and broad. The legs are thin and wear on the rails ( tibiae ) floating hair. The antennae are filiform and have 11 members. The males differ from the females in that the first three Tarsenglieder the front and middle pairs of legs are broadened and that they have suction cups on the underside. The distinguishing feature of the wetland beetles to the water beetles is that the former have an elongated, transversely divided plates on the Metasternum.

Way of life

The animals live in the water and move rather slowly and awkwardly in the zigzag style, as they alternately rowing with their legs. They usually move but rather crawling along the waters edge or bottom forward. They are predators and hunt in the share of standing water, such as ponds or swamps, whose reason is covered with mud or dead plant material. To move forward, rowing the beetle. You need to be able to receive oxygen, which is stored under the elytra occasionally emerge. You can fly and are sometimes attracted by artificial light at night. You can create by the rubbing of the abdomen and elytra noise. Eggs are laid in a gelatinous envelope of water plants.

The approximately 10 mm long larvae are broad and flattened and have a thickened upper body. In the abdomen they carry three caudal appendages ( cerci and Terminalfilum ). They also are predators, in the same habitat as the Imagines. But you do not show up for air because they breathe through gills that are located on the underside of the thorax and abdomen. In their development they go through three larval stages, where they already have functional xylem in the third stage, with which they can breathe on land. This allows them to pupate on land in moist sand and mud.

Species

• Hygrobia hermanni (Fabricius 1775)
• Hygrobia australasiae ( Clark, 1862)
• Hygrobia davidi Bedel, 1883
• Hygrobia maculata Britton, 1981
• Hygrobia niger ( Clark, 1862)
• Hygrobia wattsi Hendrich, 2001