On the mass occurrence of two rare saproxylic beetles, Cucujus cinnaberinus (Cucujidae) andDircaea australis (Melandryidae), in South Moravian fl oodplain forests

Abstract

From 2003 to 2005 saproxylic beetles were studied by means of flight interception traps in three old growth floodplain forest stands, dominated by pedunculate oak and narrow-leaved ash, near the confl uence of the Morava and Dyje rivers in South Moravia (Czech Republic). At each site 10 traps were operated for two seasons from the last third of April or beginning of May till end of September or middle of October. Analysis of the catch is underway ; the present results are based on two seasons at the Dlúhý hrúd site and the Ranšpurk National Nature Reserve, but only on one season in case of Cahnov-Soutok National Nature Reserve. The trapping yielded noteworthy high numbers of two rare and threatened saproxylic species, Cucujus cinnaberinus and Dircea australis, 10 and 63 specimens, respectively. First records of D. australis from this area, and thus from the Czech Republic, are from the 1990s. C. cinnaberinus was found exclusively in April and May, whereas D. australis was trapped from the second half of May till the first half of August, predominantly from July onwards.