Community Structure of Aquatic Insects Adapted to Lentic Water Environments, and Fine-Scale Analyses of Local Population Structures and the Genetic Structures of an Endangered Giant Water Bug Appasus japonicus

Environments such as floodplains and the marshlands of rivers, lakes and ponds, are important habitats for aquatic insects adapted to lentic water conditions. In addition, ponds and paddy fields artificially created for agriculture are also important alternative habitats for lotic water-dependent wildlife. In this study, we focused on aquatic insects in ponds in the Matsumoto Basin, located in the center of Japan. Although this is an urbanized area, aquatic animals adapted to floodplains inhabit it at a relatively high density for Japan. We conducted a multifaceted evaluation of the environments of the 33 ponds in this region and conducted a survey of the aquatic insect fauna inhabiting them. In this study, we conducted quantitative sampling, focusing on two insect orders adapted to large-scale lentic water environments (i.e., Heteroptera and Coleoptera), and observed five species of three families and 16 species of five families from the Matsumoto Basin, respectively. Within these species, eight endangered species were included. Furthermore, we carried out a genetic structure analysis for the giant water bug, Appasus japonicus, inhabiting these ponds in high density, and conducted a comparative evaluation of their genetic diversity between these ponds. A total of 530 specimens of A. japonicus were genetically analyzed for the mitochondrial DNA COI region, and 26 haplotypes were observed. The degree of genetic diversity between the ponds was clearly demonstrated. In addition, we discussed the wintering possibilities for the giant water bugs based on their corresponding surrounding environmental factors, and comprehensively discussed their “source−sink” relationships in this region. Therefore, this is a comprehensive study focused on the relevant environmental factors, diversification of their community structures, their population structures, and their genetic structure at a fine scale.

Distribution of freshwater sponges in Serbia

As data on the distribution of freshwater sponges (Porifera, Demospongiae, Spongillida) in Serbia are extremely scarce, we investigated the main Serbian rivers and lakes with respect to Porifera occurrence, for which 17 lotic and 11 lentic water bodies were selected. Sponges were found in 11 of 17 rivers (62 specimens in total) and in 3 of 11 lakes/reservoirs (seven specimens in total). Classical morphological spicule analysis was coupled with polymerase chain reaction (PCR) and gene sequencing for species identification. Among the 69 collected speci- mens, five sponge species of the family Spongillidae have been identified: Ephydatia fluviatilis (Linnaeus, 1759), Spongilla lacustris (Linnaeus, 1759), Ephydatia muelleri (Lieberkühn, 1856), Trochospongilla horrida Weltner, 1893, and Eunapius fragilis (Leidy, 1851). The most frequently found sponge in Serbian rivers was E. fluviatilis (45% of all specimens), while the least frequent was E. fragilis (6 % of all specimens). The Tisa river has the highest sponge diversity (four species). In lentic water bodies, only E. fluviatilis (four specimens) and S. lacustris (three specimens) were found. In general, sponges were infrequent and their abundance was low in Serbian fresh waters. While sponges seem to tolerate significant variations of physical and chemical parameters, some optimal values can be established.

Amphibian abnormalities and threats in pristine ecosystems in Sri Lanka

Amphibian abnormalities are caused by numerous etiologies prevailing in the environment. Since amphibians are good bio indicators of the environment, amphibian abnormalities are popularly known as a veritable ecological screening tool to assess ecosystem health. The present study was carried out encompassing within and outside the Horton Plains National Park areas, from January to November 2017. Distribution of amphibian morphological abnormalities were assessed in and around the five lentic water bodies through gross visual encounter. Six quadrates of 1m×2m were randomly placed in each sampling site. Frequency and composition of amphibian abnormalities were assessed in a total of 694 amphibians, belonging to four families and 11 species. Thereby, 4.5% and 80.87% abnormality indexes were accounted for respectively within and outside the park, comprehended surficial abnormalities, ectromelia and femoral projection abnormality types. Surficial abnormalities were the most predominant in both localities, generally occurring at the hind limb region of pre-mature stages of Taruga eques. Two lentic water bodies were identified as “abnormality hotspots” within and outside the Horton Plains National park; however, a multiplicity of possible combinations of potential causes of abnormalities were present in the environment. Hence, finding the exact causes of amphibian abnormalities are an extremely difficult exercise in the field.