Rare European donacid beetle Macroplea appendiculata PANZER, 1794 (Coleoptera: Chrysomelidae: Donaciinae) common in Polish fish ponds
ABSTRACT Macroplea appendiculata PANZER, 1794 is an extremely rare species in Poland and Europe. This paper provides new data on the ecology of this species. 24 specimens of M. appendiculata were collected in fish ponds at Samoklęski. This beetle was caught mainly with active traps placed on the bottom, but it was not found in traps set just below the water surface. The data show that M. appendiculata is a typical benthic organism, moving vertically to only a small extent. The low rate of metabolism allows this beetle to inhabit waters of varied, as well as low, oxygen content. The occurrence of the most numerous population of M. appendiculata in fish ponds, currently known in Poland, indicates the crucial role of this kind of water body as a habitat for this species.