The Afromontane Cladocera (Crustacea: Branchiopoda) of the Rwenzori (Uganda–D. R. Congo): taxonomy,ecology and biogeography

The timely characterization of high-altitude freshwater habitats allows an assessment of the diversity of its biota and provides the basis for monitoring community change. In this study, we investigate the Cladocera fauna of 29 water bodies (pools, freshwater lakes, and surrounding swamps sampled at various occasions between 2005 and 2009) in the Rwenzori Mountains (Uganda, D. R. Congo), which are part of the East African Sky Island Complex. All sites except one are located above 3700 m altitude. We include notes on the morphology, taxonomy, distribution, and ecology of each recorded taxon and describe a new species of the Alona rustica-group (Alona sphagnophila n.sp.; Chydoridae). We found 11 species of which seven are restricted to Lake Mahoma, the lowest lake in our study area (2990 m) (Alona affinis barbata, A. intermedia, Alonella exisa, Alonella nana, Daphnia cf. obtusa, Pleuroxus aduncus) and/or Lake Bujuku (Daphnia cf. curvirostris, P. aduncus) (3900 m). Two taxa (Ilyocryptus cf. gouldeni, A. sphagnophila n.sp.) are restricted to Carex/Sphagnum bogs surrounding lakes in the afroalpine zone. Pigmented populations of Chydorus cf. sphaericus occur in all the sites. It is the only cladoceran species surviving the extreme alpine and nival conditions in the Rwenzori. The species is joined by A. guttata at locations at lower altitudes (ca. 3000–4000 m), present in about half of the sites. The Rwenzori Cladocera fauna is characterized by a strong extratropical temperate component and a low level of speciation/endemism. Harboring an impoverished boreal cladoceran community, Lake Mahoma is given closer attention. At 2990 m, the lake is a cold-temperate aquatic island in the tropics and may function as a stepping stone for Palaearctic taxa. We introduce a new term for high-altitude, cold-water habitats in the tropics, which act as climatic islands for extratropical freshwater faunas, Löffler Islands, in honor of Dr Heinz Löffler. In comparison to surveys in 1961, we list five new records in Lake Mahoma, which could indicate cladoceran community changes over the past few decades at ca. 3000 m in the Rwenzori. Since the species distributions correlate to temperature and catchment properties of the lakes, the Rwenzori cladoceran fauna can be expected as sensitive indicators for local changes.     

Bioefficacy of Blumea mollis (D. Don) Merr. and Hygrophila schulii (Buch.-Ham.) (Syn. H. auriculata) against Helicoverpa armigera (Hübner)

Indiscriminate use of synthetic pesticides to control the pests causes negative effects on non-target organisms. Some of the chemicals under B and C categories are carcinogenic to humans. The present study was aimed to assess the antifeedant, larvicidal and pupicidal activities of Hygrophila schulii (syn. H. auriculata) and Blumea mollis against Helicoverpa armigera. Maximum antifeedant activity of 70.01% was observed in ethyl acetate extract of H. schulii at 5.0% concentration with LC₅₀ value of 2.0%. B. mollis ethyl acetate extract at 5.0% concentration showed antifeedant activity of 35.40% with LC₅₀ value of 8.38%. The data for antifeedant activity showed homogeneity of variances in Levene Statistics and normality in Shapiro–Wilk test. Ethyl acetate extract of H. schulii at 5.0% concentration showed 68.66% larvicidal activity with LC₅₀ value of 2.97%. It also showed 73.33% pupicidal activity and was statistically significant from other treatments. No pupicidal activity was observed in ethyl acetate extract of B. mollis. All concentrations of ethyl acetate extract of H. schulii showed promising biological activities which differed statistically from other treatments. Ethyl acetate extract of H. schulii could be used to develop new botanical formulations to manage agricultural pests.