Species Composition, Abundance and Population Structure of Malaria Vectors in Two Villages of Sudan

BackgroundFrequent monitoring of mosquito vector population is a strategy of great importance for reducing risks of disease occurrence. In Sudan, malaria is still a big threat to public health. Insecticide-based control has been undertaken for years, but there is no noticeable decrease of malaria infection nationwide.ObjectiveTo overcome this situation, a better understanding of the breeding ecology of the vectors is relevant. Here, we investigate the species composition of malaria vectors, seasonal abundance and population structure in two different villages.MethodologyMonthly samplings were performed in Abu Algoni (Sennar State) and Algerif West (Khartoum State) from June 2010 to May 2011. During each visit, immature stages were collected from potential breeding sites using dipping technique. In addition, adults were collected indoors from houses by aspiration and indoor pyrethrum spray methods. Mosquitoes were identified morphologically, the Anopheles gambiae complex diagnosed using PCR and the physiological status of females determined based on appropriate techniques. Environmental parameters namely temperature, rainfall and humidity were measured.ResultsA total of 4,932 mosquitoes comprising of 3047 larvae and 1885 adults (males and females combined) were sampled. Of these, 88.9% were collected from Abu Algoni while 11.1% were from Algerif West. Two species, An. rufipes and An. arabiensis were encountered. Anopheles rufipes was only found in Abu Algoni, while the latter was found in both villages, where it represented more than 99% of the total collection.Mosquitoes were found breeding in many types of places including canals, temporary pools of water, animal hooves, water from broken pipes, and water storage containers. No significant correlation was found between female and temperature (p>0.05). Significant correlation difference was observed between number of females of An. arabiensis and rainfall (p<0.05) and humidity (p<0.01).ConclusionsAnopheles arabiensis is the only member of An. gambiae complex detected in the present study. Seasonal abundance of An. arabiensis was observed with most during the wet rainy season in both villages. This could be associated with the availability of more breeding sites created by the rainfall. The majority were parous which indicates high survival rates and thus high vectorial capacity in transmitting malaria.

Seasonal Abundance and Spatial Pattern of Distribution of Liriomyza trifolii (Diptera: Agromyzidae) and Its Parasitoid on Bean and Squash in South Florida

American serpentine leafminer, Liriomyza trifolii, is a polyphagous insect pest that feeds on a wide range of vegetable and ornamental plants around the world. To develop an effective IPM program, information on the seasonal field distribution and population dynamics of leafminer and its parasitoids is very important. Therefore, seasonal abundances and spatial distributions of, L. trifolii on snap bean and squash were studied during four crop growing periods between 2013 to 2015 in Homestead, Florida. The mean numbers of mines, larvae, pupae, emerged adults, and parasitoids on snap bean were highest at 2 weeks after planting during all four growing periods. Whereas, the mean numbers of mines, larvae, pupae, emerged adults, and parasitoids on squash were highest at 3 weeks after planting during all four growing periods. L. trifolii distributions tended to be aggregated on snap bean at 2 weeks after planting during most of growing periods but had uniform distributions on squash at 2 weeks after planting during most of growing periods. Similar results were seen on the distribution of leafminer parasitoids on both bean and squash.

Insects as a food source for indigenous communities in Colombia: a review and research perspectives

Insects have been used worldwide as a source of food, and edible species are eaten both as immature (eggs, larvae, pupae, and nymphs) and in some cases as adults. In this regard, several scholars and researchers seek to promote an alternative entomological trend and highlight the potential of insects as a high-quality nutritional option. The consumption of various edible species contributes to the nutritional health of indigenous, rural peoples, as well as those individuals who live in urban areas and use this kind of food resource, in accordance with insects’ seasonal abundance. Colombia, due to its sociocultural origin, stands out as one of the Latin American countries that have the habit of consuming insects by presenting both biological and ethnic diversity. However, the use and diversity of edible insects in the country have been little studied. This review summarises the current status related to the knowledge of insects as food resources, with emphasis on ethnic groups established in the country. In Colombia, 69 edible insect species are currently reported, distributed in 49 genera, 27 families and 10 orders, and ingested by approximately 13 ethnic groups belonging principally to the Amazon and Caribbean regions. Guidelines and protocols are provided to establish research priorities in the study and use of edible insects in Colombia. In this way, the proposal of a general framework for the study and conservation of edible insect species, integrating a bioecological, socio-economic and institutional approach, will provide new perspectives for food security in this era of world food scarcity, and can play an interdisciplinary role (forestry, traditional medicine, agriculture, livestock) in mitigating the current global food crisis.

Temporal and Spatial Distribution of Zooplankton Inhabiting Sandy and Muddy Shore Habitats at Jazan Coastal Area

Few studies were made about zooplankton distribution in Jazan coastal area. The present study dealt with the identification of zooplankton at the sandy shore (AlSalwa coast) and mangrove muddy shore (Turfa peninsula) at the Almarjan coast. Species richness and population density at different seasons were determined for both study areas between May 2016-April 2017. Conductivity, pH, water temperature, and salinity were measured. The relationship between water characters and the seasonal abundance of zooplankton seasons was examined through regression analysis. Ciliates, Rotifers, Nauplius larva, Gammarus sp., Veliger larva, Nematodes, Planaria, Copepods, and Kinorhyncha were recorded for both study areas. The highest species richness and population density were recorded during the summer season for Almarjan sandy shore and Turfa peninsula mangrove. Ciliates were the most abundant zooplankton on the sandy shore, while Kinorhyncha was the least abundant. The zooplankton Nematode was the most abundant at the Turfa Peninsula mangrove, whereas Gnathostomulida was the least abundant. Conductivity, salinity, and water temperature showed a significant regression relationship (P<0.05) with zooplankton abundance. Data was discussed to highlight the role of zooplankton abundance in the mangrove and sandy shore ecosystem.

Humpback whales in Banderas Bay, Mexico: relative abundance and temporal patterns between 2004 and 2017

Banderas Bay, Mexico is an important breeding and transit area for the North Pacific humpback whale (Megaptera novaeangliae) population. In this paper we estimated relative abundance (RA = number of whales/hours of navigation) as a proxy to assess population temporary patterns in the area. We analyzed data from 14 breeding seasons (2004-2017), collected between December and March each winter. A total of 8,013 whales were observed in 1,394.6 navigation hours. Average seasonal RA was 5.7 whales per hour with a maximum of 7.5 (2013) and a minimum of 4.0 (2016). Sea surface temperature (SST) averaged 25.1°C and remained within the range considered optimal for humpback whale reproduction areas. SST showed no significant correlation with RA (r = 0.183). Inter-seasonal RA values suggested an increase throughout the study period, although the increase was not statistically significant (R = 0.32; R2 = 0.10; t = 1.15, p > 0.05). Intra-seasonal analyses showed that RA in December and January were significantly higher (U = 150, p < 0.05) than in February and March; this pattern was consistent throughout the seasons of study. These results represent a shift in the intra-seasonal abundance peak relative to previous studies when most whales were observed between January and February. It is important to recognize changes in population parameters of humpback whales in breeding areas to improve management practices. This study also highlights the potential of opportunistic platforms, such as whale watching tour boats, as viable sources of quality information, particularly in contexts when funding is limited.

Remarkably coherent population structure for a dominant Antarctic Chlorobium species

Background In Antarctica, summer sunlight enables phototrophic microorganisms to drive primary production, thereby “feeding” ecosystems to enable their persistence through the long, dark winter months. In Ace Lake, a stratified marine-derived system in the Vestfold Hills of East Antarctica, a Chlorobium species of green sulphur bacteria (GSB) is the dominant phototroph, although its seasonal abundance changes more than 100-fold. Here, we analysed 413 Gb of Antarctic metagenome data including 59 Chlorobium metagenome-assembled genomes (MAGs) from Ace Lake and nearby stratified marine basins to determine how genome variation and population structure across a 7-year period impacted ecosystem function. Results A single species, Candidatus Chlorobium antarcticum (most similar to Chlorobium phaeovibrioides DSM265) prevails in all three aquatic systems and harbours very little genomic variation (≥ 99% average nucleotide identity). A notable feature of variation that did exist related to the genomic capacity to biosynthesize cobalamin. The abundance of phylotypes with this capacity changed seasonally ~ 2-fold, consistent with the population balancing the value of a bolstered photosynthetic capacity in summer against an energetic cost in winter. The very high GSB concentration (> 108 cells ml−1 in Ace Lake) and seasonal cycle of cell lysis likely make Ca. Chlorobium antarcticum a major provider of cobalamin to the food web. Analysis of Ca. Chlorobium antarcticum viruses revealed the species to be infected by generalist (rather than specialist) viruses with a broad host range (e.g., infecting Gammaproteobacteria) that were present in diverse Antarctic lakes. The marked seasonal decrease in Ca. Chlorobium antarcticum abundance may restrict specialist viruses from establishing effective lifecycles, whereas generalist viruses may augment their proliferation using other hosts. Conclusion The factors shaping Antarctic microbial communities are gradually being defined. In addition to the cold, the annual variation in sunlight hours dictates which phototrophic species can grow and the extent to which they contribute to ecosystem processes. The Chlorobium population studied was inferred to provide cobalamin, in addition to carbon, nitrogen, hydrogen, and sulphur cycling, as critical ecosystem services. The specific Antarctic environmental factors and major ecosystem benefits afforded by this GSB likely explain why such a coherent population structure has developed in this Chlorobium species.

Phenology, Seasonal Abundance, and Host-Plant Association of Spittlebugs (Hemiptera: Aphrophoridae) in Vineyards of Northwestern Italy

Spittlebugs (Hemiptera: Aphrophoridae) are the vectors of the bacterium Xylella fastidiosa (Xf) in Europe. Xf may cause severe epidemics in cultivated plants, including grapevines. To assess the threat represented by the bacterium to grapevines, detailed information on the vectors’ phenology, density, and ecology in vineyards is needed. The aim of the present work was to describe spittlebug diversity, phenology, and host-plant association in the vineyard agroecosystem. Two separate field surveys of nymphal and adult spittlebug populations, i.e., a two-year survey of a single site and a one-year survey of three sites, were performed in vineyards of northwestern Italy in three consecutive years. Philaenus spumarius was the most common species, reaching average nymph densities on herbaceous cover up to 60–130 nymphs/m2. Adults were sampled on grapevines from May to September, with a peak in June (up to 0.43 insects/sweep). Herbaceous cover was colonized after egg hatching and in late summer for oviposition, while wild woody hosts represented a refuge during summer. The results show that spittlebugs can reach high population levels in vineyards, at least in the areas where the ground is covered by herbaceous plants for the whole season and the use of insecticides is moderate. The extended presence of P. spumarius adults on grapevines represents a serious risk factor for the spread of Xf. The scenarios of Xf establishment in vineyards in northwestern Italy and Europe are discussed in relation to the abundance, phenology, and plant association of spittlebugs.