a b s t r a c tOur study describes and evaluates environmental influences on assemblages of aquatic Coleoptera and Heteroptera in artificial ponds situated near Lake Steinhude in Lower Saxony (Germany). We determined temporal dynamics and colonization patterns for 14 ponds of different age. In total, we recorded 4941 individuals that represented 87 species of aquatic beetles and bugs. Between 30 and 40 species were found in most of the ponds. Heteropteran species of the families Corixidae and Notonectidae acted as pioneer species in new ponds, while aquatic coleopterans predominated in older ponds. The results of Canonical Correspondence Analyses (CCA) showed that among the key factors affecting community structure were land use, vegetation cover, water chemistry and the age of the ponds. We found that the distribution of adjacent ponds on areas with different land use has a positive influence on the diversity and abundance of the aquatic insect fauna.

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SUMMARY During diving explorations of anchialine cave systems on Abaco Island, Bahamas, we collected five larvae that represent different developmental stages of remipede crustaceans. Based on four early naupliar stages and a postnaupliar larva, it is possible for the first time to reconstruct the postembryonic development of Remipedia some 25 years after their discovery. These specimens begin to fill in some critical gaps in our knowledge of this important group of crustaceans.

We describe Speleonectes atlantida n. sp. as the third species of Remipedia that was found outside the main distribution area of this group in the Caribbean region. S. atlantida was collected by cave divers equipped with closed circuit rebreathers from the far interior of the Túnel de la Atlántida, an anchialine volcanic lava tube, on the Canarian island of Lanzarote. The new species occurs in sympatry with S. ondinae, to which it is morphologically closely related. S. atlantida can be distinguished from S. ondinae by a more slender habitus and smaller pleurotergites in the posterior trunk. The valid status of S. atlantida as a new species of Remipedia could be corroborated by intra-and interspecific comparisons of 16S rDNA and CO1 sequence data.

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