MACRÓFITAS AQUÁTICAS DA COLEÇÃO DO HERBÁRIO DO MARANHÃO (MAR) = AQUATIC MACROPHYTES OF THE COLLECTION OF HERBARIUM OF MARANHÃO (MAR)

Os estudos de macrófitas aquáticas têm contribuído para compreensão estrutural e funcional deste grupo de plantas nos ambientes em questão. Mesmo com a importância dessas pesquisas para a conservação da biodiversidade e dos recursos hídricos, os estudos básicos sobre macrófitas ainda são insuficientes diante da dimensão e do grande número de ecossistemas aquáticos no Brasil. Quando falamos do Maranhão esses estudos são ainda mais escassos tendo em vista que a nossa rede hídrica é composta por 12 bacias hidrográficas que corresponde a aproximadamente 60% do território do Estado. Com intuito de atender essa demanda e conhecer a diversidade de espécies e suas distribuições nos ecossistemas maranhenses, foi feito um levantamento das macrófitas aquáticas registradas no acervo do Herbário Maranhão (MAR), complementado com os dados do SpeciesLink. A lista gerada segue a proposta de classificação do APG IV (2016) incluindo informações como: voucher, local de coleta e formas de vida. Foi listado um total de 40 espécies, distribuídas em 28 gêneros e 18 famílias. As famílias mais numerosas foram Cyperaceae e Onagraceae (5 espécies cada), Araceae e Pontederiaceae (4 spp.) e Alismataceae, Lentibulariaceae e Poaceae (3 spp.). Em relação às formas biológicas, 35% são plantas emergentes, 25% anfíbias; 20% flutuantes livres e 20% flutuantes fixas. O material foi registrado em 19 municípios do Estado e entre as primeiras coletas e outros registros houve um hiato de coleta por 20 anos, o que reforça a falta de dados para a área e a necessidade de maior esforço amostral para o Estado do Maranhão.ABSTRACTStudies of aquatic macrophytes have contributed to the conservation of biodiversity and water resources. However, basic research on macrophytes are still insufficient given the size and large number of aquatic ecosystems in Brazil. Regarding Maranhão, such studies are even scarcer in view of our water network composed of 12 hydrographic basins that correspond to approximately 60% of the territory of Maranhão State. Thus, the objective of the study was to know the diversity and distribution of macrophyte species in the ecosystems of Maranhão registered at the Herbarium in Maranhão (MAR). For this, surveys were carried out in the collection of Herbarium MAR complemented with data from the SpeciesLink databank, and included information such as voucher, collection site and life forms. The survey included 40 species were listed, distributed into 28 genera and 18 families. The most numerous families were Cyperaceae and Onagraceae (5 species, each),Araceae and Pontederiaceae (4 species, each), and Alismataceae, Lentibulariaceae and Poaceae (3 species, each). Regarding biological forms, 35% are emergent, 25% amphibious; 20% free floatingand 20% rooted floating plants. The material was registered in 19 municipalities of the Maranhão State. Among the first collections and recent records there was a collection gap for 20 years, that highlights the need for more sampling effort for Maranhão state.

Gerromorpha (Insecta, Hemiptera, Heteroptera) from eastern Maranhão state, northeastern Brazil

The infraorder Gerromorpha (Insecta, Hemiptera, Heteroptera) comprises semiaquatic bugs, most of which live on the water surface, among floating plants or at the margins of water bodies. We made collections of these insects in the Itapecuru and Parnaíba hydrographical basins in eastern Maranhão state, northeastern Brazil, from January to December 2019. Based on the material obtained, we present new records for 23 species, 20 of which are recorded for the first time from Maranhão state.

Microgaster godzilla (Hymenoptera, Braconidae, Microgastrinae), an unusual new species from Japan which dives underwater to parasitize its caterpillar host (Lepidoptera, Crambidae, Acentropinae)

A new species of Microgastrinae (Hymenoptera: Braconidae) parasitoid wasp, Microgaster godzilla Fernandez-Triana & Kamino, is described from Japan. From a biological and morphological perspective this is a very unusual species. It represents only the third known microgastrine to be aquatic, and the first one to be found entering the water. The female wasp searches for its hosts, aquatic larvae of Elophila turbata (Lepidoptera: Crambidae), mostly by walking over floating plants, but occasionally diving underwater for several seconds to force the larva out of its case, when it is quickly parasitized (parasitization was always observed above water). The unique searching behaviour of M. godzilla as well as its parasitization of aquatic larvae was filmed and it is presented here. The wasp has simple tarsal claws, which are elongate and strongly curved, similar to those found in the related genus Hygroplitis; they seem to represent an adaptation for gripping to the substrate when entering the water. The new species is described based on morphological, molecular (DNA barcoding), biological and ethological data. Additionally, we provide detailed diagnoses to recognize M. godzilla from all other described species of Microgaster and Hygroplitis in the Palearctic, Nearctic and Oriental regions.

Potential of aquatic weeds to improve water quality in natural waterways of the Zambezi catchment

One prominent effect of nutrient pollution of surface waters is the mass invasion of floating plants, which can clog waterways, disrupting human use of aquatic systems. These plants are widely vilified and motivate expensive control campaigns, but their presence may be providing a poorly recognized function in the cycling of excess nutrients. The capacity for floating plants to absorb nutrients from surface water has been understood for decades, primarily from their use in constructed wetlands for wastewater treatment. Yet, in natural settings, there has not been to date any effort to quantify whether floating plant invasions represent important pools or fluxes of nutrients relative to those of the river catchments in which they occur. We found that seasonal hydrologic cycles in the Zambezi trap and flush floating plants from river choke points, such as dams and river confluences, on an annual basis. Peak plant biomass at such choke points constitutes a proxy for estimating annual plant-bound nutrient loads. We assessed the significance of floating vegetation as nutrient sinks by comparing annual plant-bound nutrient loading to conventional river nutrient loading (dissolved and particulate) for four tributaries of the Zambezi River in Zambia. We found that the relative importance of floating vegetation was greatest in the more urbanized catchments, such as the Maramba River draining the city of Livingstone, representing approximately 30% and 9% of annual digestible phosphorus and nitrogen flux respectively. We also found plant-bound phosphorus to be important in the Kafue River (19%), draining the industrial town of Kafue and extensive sugarcane plantations. These results demonstrate the great potential of floating plants to take up excess nutrients from natural river systems. Given the importance of hydrology in the life cycle of floating vegetation, controlled dam discharges may have an important role in managing them and their water quality treatment functions.