TL;DR: This study demonstrates that there is an abundance of local Mesocyclops spp.
Abstract: This paper describes the process of expanding a successful dengue control program in 3 provinces in northern Vietnam into a national one and demonstrates the presence of a rich, low-cost resource that could have similar applicability to other countries in the region. The cornerstone of the preventive strategy is larval control of Aedes aegypti (L.), the major vector, using predators such as copepods, Mesocyclops spp., aided by the corixid bug Micronecta quadristrigata Bredd, and fish in large water storage containers. From 1989 to 1998, 9 species of Mesocyclops (M. woutersi Van de Velde, M. aspericornis (Daday), M. ruttneri Kiefer, M. thermocyclopoides Harada, M. affinis Van de Velde, M. ogunnus Onabamiro, M. yenae Holynska, M. cf. pehpeiensis Hu, and M. dissimilis Defaye and Kawabata) were found in natural and artificial habitats in 26 provinces throughout Vietnam. The predatory capacities of 6 of these were evaluated in the laboratory. This indicated that daily consumption/killing averaged between 16 and 41 Ae. aegypti larvae per copepod. From detailed evaluations in 9 provinces, Mesocyclops spp. were surprisingly common in 8,413 artificial containers (concrete tanks, wells, ornamental ponds and in the south, large jars). Because of existing practices for washing and water transfer from ponds and lakes in Ha Tay and Ha Bac, Mesocyclops spp. already occurred in 60-100% of the water storage containers. When the relationship between the presence or absence of Mesocyclops and Aedes larvae in 5,111 containers was analyzed by the chi-square test, their distributions were significantly related, indicating control (odds ratio = 0.56). When 3,426 containers that did not contain Mesocyclops or fish were analyzed in relation to the distribution of Aedes larvae, those with Micronecta also had significantly less Aedes (odds ratio = 0.43). Therefore, this study demonstrates that there is an abundance of local Mesocyclops spp. in Vietnam that can be incorporated into specifically designed community-based control programs aided by Micronecta and fish.
TL;DR: Various food resources, especially the benthos, appear to be under-utilized and so it is possible that further species could be introduced to enhance the commercial fishery.
Abstract: Lake Naivasha is a freshwater lake situated in the eastern rift valley of Kenya. Only five species of fish are present, all of which have been introduced. They are Oreochromis leucostictus, Tilapia zillii, Micropterus salmoides (largemouth bass), Barbus amphigramma and Poecilia reticulata (guppy). The first three of these form the basis of an important gill net fishery and bass are also taken by rod and line for sport. Barbus are occasionally caught by dip net. Actual and potential yields for the Lake Naivasha fishery are discussed and the fishery is shown to be under-performing. The feeding regimes of the commercially exploited fish were examined in the context of available food supply, in particular the benthic fauna. Small bass depend heavily on Micronecta and large bass mostly take crayfish. Detritus predominates in the diet of Oreochromis leucostictus and Tilapia zillii but the former also eats algae and the latter, Micronecta and macrophyte. Various food resources, especially the benthos, appear to be under-utilized and so it is possible that further species could be introduced to enhance the commercial fishery.
TL;DR: Hydrologic and geomorphic factors influenced assemblages at the macroscale, whereas microhabitat diversity dominated at the mesoscale.
Abstract: The abundance and richness of macroinvertebrates in the lower Murray and Darling rivers were examined at a macroscale (rivers), mesoscale (billabongs, backwaters, channel) and microscale (vegetation, snags, substrata). In the Darling, insects dominated (85% of taxa, 81% of individuals); the richest taxa were Diptera (26 taxa) and Coleoptera (15 taxa) and the most abundant were Hemiptera (47%) and Diptera (35%). In the Murray, insects again dominated (84% of taxa, 52% of individuals), particularly Diptera (22 taxa), Coleoptera (12 taxa) and Hemiptera (9 taxa), but there were more crustaceans (9% of taxa, 47% of individuals, particularly the atyid shrimp Paratya australiensis). Both assemblages were uneven: in the Darling, >50% of biomass was Micronecta spp. (Corixidae), Dicrotendipes sp. (Chironomidae) and Macrobrachium australiense (Palaemonidae); in the Murray, 70% of biomass was P. australiensis and Caridina mccullochi (Atyidae) and the insects Micronecta spp. (Corixidae) and Chironomus sp. (Chironomidae). Abundances generally were greatest in the Murray. Hydrologic and geomorphic factors influenced assemblages at the macroscale, whereas microhabitat diversity dominated at the mesoscale.
TL;DR: Two genera and 37 species of Micronectidae are now reported from Vietnam: Synaptonecta Lundblad, 1933 with only one species, S. issa (Distant, 1910), and MicronECTa with 36 species.
Abstract: The taxonomy of Micronectidae in Vietnam is reviewed. Based on our cumulative collections during 2001–2020, 11 new species of Micronecta Kirkaldy, 1897 are documented and described in this study: M. acuminata sp. nov., M. arcuata sp. nov., M. caperata sp. nov., M. clavata sp. nov., M. cultellata sp. nov., M. fulvopicta sp. nov., M. nieseri sp. nov., M. pingae sp. nov., M. sinuata sp. nov., M. undulata sp. nov., and M. vietnamica sp. nov. Nine species are recorded from Vietnam for the first time: M. decorata Lundblad, 1933, M. drepani Nieser, 2000, M. erythra Nieser, Chen & Yang, 2005, M. fugitans Breddin, 1905, M. johorensis Fernando, 1964, M. melanochroa Nieser, Chen & Yang, 2005, M. ornitheia Nieser, Chen & Yang, 2005, M. sahlbergi (Jakovlev, 1881), and M. tuwanoni Nieser, Chen, Leksawasdi, Thanyakam & Duangsupa, 2004. Thus, in this study, two genera and 37 species of Micronectidae are now reported from Vietnam: Synaptonecta Lundblad, 1933 with only one species, S. issa (Distant, 1910), and Micronecta with 36 species. A key to all species occurring in Vietnam, subgeneric diagnoses, and a key to all current subgenera of Micronecta are provided.
TL;DR: In this article, the first records of M.griseola from the territory of the Middle Urals (Russia) were presented, and the distribution of the species and the features of its biology were considered.
Abstract: Background Micronecta (Micronecta) griseola Horvath, 1899 is a representative of water bugs of the family Corixidae. It is expanding its range eastwards according to our observations in Russia. In the last decade, the species has become more common in Western Siberia. New information The article presents the first records of M.griseola from the territory of the Middle Urals (Russia). The distribution of the species and the features of its biology are considered.