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.

Population status and breeding ecology of Black Kite Milvus migrans (Boddaert, 1783) in Pokhara Valley, Nepal

The present study attempted to provide basic knowledge on population status, breeding success and general behaviours of Black kites in the Pokhara Valley of Nepal. Nesting and roosting sites were directly observed to count the bird in the fields during the study period from December 2019 to May 2020. A total of 308 individuals of Black kites were recorded. The highest and least number was recorded in February (n=67) and May (n=31) respectively. The breeding success was found to be 47.22%. The average height, girth and canopy cover of the nesting tree were found at 16.59m, 2.23m and 63.30% respectively. About 67% of nests observed were found active during the breeding season. The Spearman rank correlation coefficient showed a perfect positive relationship between the number of chicks and the number of the nest (r = 1). Bombax ceiba and Dalbergia sissoo were the trees on which the maximum number of nests were observed.

Phylogeny, taxonomy and flower-breeding ecology of the Colocasiomyia cristata species group (Diptera: Drosophilidae), with descriptions of ten new species

The phylogeny of the Colocasiomyia cristata species group is reconstructed as a hypothesis, based on DNA sequences of two mitochondrial and six nuclear genes and 51 morphological characters. The resulting tree splits this species group into two clades, one of which corresponds to the colocasiae subgroup. Therefore, a new species subgroup named as the cristata subgroup is established for the other clade. Within the cristata subgroup, three subclades are recognized and each of them is defined as a species complex: the cristata complex composed of five species (including three new ones: C. kinabaluana sp. nov., C. kotana sp. nov. and C. matthewsi sp. nov.), the sabahana complex of two species (C. sabahana sp. nov. and C. sarawakana sp. nov.), and the xenalocasiae complex of five species (including C. sumatrana sp. nov. and C. leucocasiae sp. nov.). There are, however, three new species (C. ecornuta sp. nov., C. grandis sp. nov. and C. vieti sp. nov.) not assigned to any species complex. In addition, breeding habits are described for four cristata-subgroup species, each of which monopolizes its specific host plant. And, data of host-plant use are compiled for all species of the cristata group from records at various localities in the Oriental and Papuan regions. The evolution of host-plant selection and sharing modes is considered by mapping host-plant genera of each species on the phylogenetic tree resulting from the present study.

New Nesting Records and Breeding Ecology Observations of Rufous-legged Owls in the Mediterranean Temperate Forest of Central Chile

ABSTRACT The Rufous-legged Owl (Strix rufipes) is the southernmost Strix owl species and its breeding ecology remains little known. We report new observations on the species' breeding ecology, including clutch size, egg size, duration of the incubation and nestling periods, and nestling diet. We conducted our observations on nests found during the summers of 1999 through 2004 in a forestry landscape of central Chile, dominated by Monterey pine (Pinus radiata) plantations with intermixed fragments of native southern beech (Nothofagus) forests. Clutch size was two eggs (n = 2 nests), with one egg larger than the other (mean = 48.8 × 40.1 mm). The incubation period was 30 d and the nestling period 34 d. We analyzed 10 pellets from nestling owls and identified 45 prey items, mostly dominated by large beetles, grasshoppers, and rodents (native and exotic). This information, though based on a limited number of nests, provides baseline ecological data that can inform future studies.

Technical Workflow Development for Integrating Drone Surveys and Entomological Sampling to Characterise Aquatic Larval Habitats of Anopheles funestus in Agricultural Landscapes in Côte d’Ivoire

Land-use practices such as agriculture can impact mosquito vector breeding ecology, resulting in changes in disease transmission. The typical breeding habitats of Africa’s second most important malaria vector Anopheles funestus are large, semipermanent water bodies, which make them potential candidates for targeted larval source management. This is a technical workflow for the integration of drone surveys and mosquito larval sampling, designed for a case study aiming to characterise An. funestus breeding sites near two villages in an agricultural setting in Côte d’Ivoire. Using satellite remote sensing data, we developed an environmentally and spatially representative sampling frame and conducted paired mosquito larvae and drone mapping surveys from June to August 2021. To categorise the drone imagery, we also developed a land cover classification scheme with classes relative to An. funestus breeding ecology. We sampled 189 potential breeding habitats, of which 119 (63%) were positive for the Anopheles genus and nine (4.8%) were positive for An. funestus. We mapped 30.42 km2 of the region of interest including all water bodies which were sampled for larvae. These data can be used to inform targeted vector control efforts, although its generalisability over a large region is limited by the fine-scale nature of this study area. This paper develops protocols for integrating drone surveys and statistically rigorous entomological sampling, which can be adjusted to collect data on vector breeding habitats in other ecological contexts. Further research using data collected in this study can enable the development of deep-learning algorithms for identifying An. funestus breeding habitats across rural agricultural landscapes in Côte d’Ivoire and the analysis of risk factors for these sites.

Basking shark sub-surface behaviour revealed by animal-towed cameras

While biologging tags have answered a wealth of ecological questions, the drivers and consequences of movement and activity often remain difficult to ascertain, particularly marine vertebrates which are difficult to observe directly. Basking sharks, the second largest shark species in the world, aggregate in the summer in key foraging sites but despite advances in biologging technologies, little is known about their breeding ecology and sub-surface behaviour. Advances in camera technologies holds potential for filling in these knowledge gaps by providing environmental context and validating behaviours recorded with conventional telemetry. Six basking sharks were tagged at their feeding site in the Sea of Hebrides, Scotland, with towed cameras combined with time-depth recorders and satellite telemetry. Cameras recorded a cumulative 123 hours of video data over an average 64-hour deployment and confirmed the position of the sharks within the water column. Feeding events only occurred within a metre depth and made up ¾ of the time spent swimming near the surface. Sharks maintained similar tail beat frequencies regardless of whether feeding, swimming near the surface or the seabed, where they spent surprisingly up to 88% of daylight hours. This study reported the first complete breaching event and the first sub-surface putative courtship display, with nose-to-tail chasing, parallel swimming as well as the first observation of grouping behaviour near the seabed. Social groups of sharks are thought to be very short term and sporadic, and may play a role in finding breeding partners, particularly in solitary sharks which may use aggregations as an opportunity to breed. In situ observation of basking sharks at their seasonal aggregation site through animal borne cameras revealed unprecedented insight into the social and environmental context of basking shark behaviour which were previously limited to surface observations.

The Effect of Breeding Habitat Characteristics on the Larval Abundance of Aedes Vector Mosquitoes (Diptera: Culicidae) in Three Localities, Galle District, Sri Lanka

Dengue has become a national burden in Sri Lanka, and the understanding of breeding ecology of vectors, Aedes aegypti Linnaeus and Aedes albopictus Skuse, is the most effective way to control the disease. The present study was undertaken to investigate the relative larval abundance of Ae. aegypti and Ae. albopictus in different types and characteristics of containers in three selected localities in Galle district, Sri Lanka. Totally, 550 containers were positive for both Ae. aegypti and Ae. albopictus larvae. Aedes albopictus showed the high larval abundance in all studied sites. The larval abundance of artificial containers (90.57%) was high than that of natural containers (9.43%) for both Aedes spp. ( P < 0.05 ). The breeding preference for A. aegypti was high in tires (rubber) (17.82%), while plastic cups (28.00%) were the most preferable container type for Ae. albopictus. Dark color containers than light color containers ( P < 0.05 ) and containers with leaf litter accumulated as detritus ( P < 0.05 ) showed high relative larval abundance for both Aedes species. Containers with 50–100 ml volume of water showed the highest relative abundance of both Ae. aegypti (29.28%) and Ae. albopictus (41.79%) ( P > 0.05 ). The high larval abundance of Aedes recorded in ground level containers (1–5 cm) and their abundance decreased significantly with the increasing of height where containers were found (1–20 cm) ( P < 0.05 ). The significantly high relative abundance was observed with the increase of the shady level for Ae. aegypti (57.34%) and Ae. albopictus (61.32%) ( P < 0.05 ). This knowledge will be helpfull to implement dengue surveillance programs in the area.