Environmental & Physical Sciences

Environmental & Physical Sciences Research Papers/Topics

Mosquito Species Succession and Physicochemical Factors Affecting Their Abundance in Rice Fields in Mwea, Kenya

Abstract: The succession of mosquito species and abiotic factors affecting their distribution and abundance in rice (Oryza spp.) Þelds was investigated over a 16-wk rice growing cycle covering the period between January and May 2006. Fifteen experimental rice plots were sampled for mosquito larvae and characterized based on rice height, number of tillers, ßoating vegetation cover, water depth, water temperature, turbidity, salinity, pH, dissolved oxygen, total dissolved solids, and conduct...

Effect of Discriminative Plant-sugar Feeding on the Survival and Fecundity of Anopheles gambiae

Abstract: Background: A previous study showed for Anopheles gambiae s.s. a gradation of feeding preference on common plant species growing in a malaria holoendemic area in western Kenya. The present follow-up study determines whether there is a relationship between the mosquito's preferences and its survival and fecundity. Methods: Groups of mosquitoes were separately given ad libitum opportunity to feed on five of the more preferred plant species (Hamelia patens, Parthenium hysterophorus, R...

Monooxygenase Levels and Knockdown Resistance (kdr) Allele Frequencies in Anopheles Gambiae and Anopheles Arabiensis in Kenya

Abstract: ABSTRACT Pyrethroid-treated bed-nets and indoor spray are important components of malaria control strategies in Kenya. Information on resistance to pyrethroid insecticides in Anopheles gambiae and An. arabiensis populations is essential to the selection of appropriate insecticides and the management of insecticide resistance. Monooxygenase activity and knockdown resistance (kdr) allele frequency are biochemical and molecular indicators of mosquito resistance to pyrethroids. This st...

Mosquito larvicidal constituents from Lantana viburnoides sp viburnoides var kisi (A. rich) Verdc (Verbenaceae)

Abstract: Background & objectives: Lantana viburnoides sp viburnoides var kisi is used in Tanzania ethnobotanically to repel mosquitoes as well as in traditional medicine for stomach ache relief. Bioassay-guided fractionation and subtraction bioassays of the dichloromethane extract of the root barks were carried out in order to identify the bioactive components for controlling Anopheles gambiae s.s. mosquito larvae. Methods: Twenty late III or early IV instar larvae of An. gambiae s.s. were ...

Constant Temperature and time Period Effects on Anopheles gambiae Egg Hatching

Abstract: Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) egg development and its relation to environmental parameters is an understudied aspect of vector biology. Although several studies have illustrated the dramatic effects of temperature on egg development, egg hatching dynamics remain unclear. The objective of this study was to expose An. gambiae eggs to various temperatures for different lengths of time and determine the impact on egg development and hatching count. Batches ...

Bugs with Backpacks Deter Vision-guided Predation by Jumping Spiders

Abstract: As a case study of how insects use masks as a defence against vision-guided predators, an experimental study was carried out using Acanthaspis petax, a reduviid bug (‘ant bug’) that covers itself with a ‘mask’, or ‘backpack’, made from carcasses of its preferred prey (ants), and three salticid spider species, Hyllus sp., Plexippus sp. and Thyene sp., salticids being predators with exceptionally acute vision. The ant bugs and the salticids were from the Lake Victoria reg...

Host plant forensics and olfactory-based detection in Afro-tropical mosquito disease vectors

Abstract: The global spread of vector-borne diseases remains a worrying public health threat, raising the need for development of new combat strategies for vector control. Knowledge of vector ecology can be exploited in this regard, including plant feeding; a critical resource that mosquitoes of both sexes rely on for survival and other metabolic processes. However, the identity of plant species mosquitoes feed on in nature remains largely unknown. By testing the hypothesis about selectivity...

Studies of Transgenic Mosquitoes in Disease-Endemic Countries: Preparation of Containment Facilities

Abstract: Novel approaches to area-wide control of vector species offer promise as additional tools in the fight against vectored diseases. Evaluation of transgenic insect strains aimed at field population control in disease-endemic countries may involve international partnerships and should be done in a stepwise approach, starting with studies in containment facilities. The preparations of both new-build and renovated facilities are described, includingworking with local and national regula...

When it looks and walks like an ant. Learning & Behavior

Abstract: Some jumping spiders (family Salticidae) bear a striking resemblance to ants, a dangerous type of prey, both in terms of their appearance and in terms of how they move. Recent research has taken important steps toward determining whether predators categorize these spiders as ants on the basis of the way they move.

Edible insect value chains in Africa

Abstract: This special issue was organised in the context of the 22nd meeting of the Association of African Insect Scientists (AAIS), in Wad Medani, Sudan in 2017. The aim was to ‘support impactful research that will yield genuine edible insects products and sustain value chains that enhance food and nutritional security and support sustained livelihoods in Africa’. The issue is composed of contributions from the following countries: Kenya, Uganda, Burundi, Nigeria,Mali, Burkina Faso, Ca...

Vision-based Ability of an Ant-mimicking Jumping Spider to Discriminate Between Models, Conspecific Individuals and Prey

Abstract: Myrmarachne assimilis, an ant-like (myrmecomorphic) jumping spider (Araneae, Salticidae) from the Philippines, is a Batesian mimic of Oecophylla smaragdina, the Asian weaver ant. Salticids are well known for their acute eyesight and the elaborate vision-based display behaviour they adopt during encounters with conspecific individuals, but most salticids are not myrmecomorphic. Despite its unusual morphology, M. assimilis adopts display behaviour during intraspecific interactions th...

Spatial panorama of malaria prevalence in Africa under climate change and interventions scenarios. International

Abstract: Background: Malaria is highly sensitive to climatic variables and is strongly infuenced by the presence of vectors in a region that further contribute to parasite development and sustained disease transmission. Mathematical analysis of malaria transmission through the use and application of the value of the basic reproduction number (R0) threshold is an important and useful tool for the understanding of disease patterns. Methods: Temperature dependence aspect of R0 obtained from dy...

Push-pull technology enhances resilience to climate change and prevents land degradation: Perceptions of adopters in western Kenya

Abstract: Climate change and land degradation adversely affect food security in sub-Saharan Africa (SSA). Smallholder farmers are the most affected. Therefore, it is imperative to identify technologies that boost resilience to climate change, and restore lands. Push-pull technology is among proposed solutions. This technology controls stem borers, fall armyworm, striga, mycotoxins; improves availability of nitrogen and phosphorus, and stores increased carbon in biomass and soils. Though much...

Advances in insects for food and feed

Abstract: This Special Issue presents the outcomes from the 23rd African Association of Insect Scientists' Conference held in Cote D’Ivoire, in connection with similar initiatives within and outside Africa. Over 65 scientific papers from several countries, worldwide, were submitted, of which about 40 were accepted and published. The issue focused on new advances in the value chain of edible insects in Africa and beyond. An innovative light-emitting diode technology for mass harvesting of e...

Plant nutrient quality impacts survival and reproductive fitness of the dengue vector Aedes aegypti

Abstract: Background: In a recent study using DNA barcoding, we identifed the plants fed upon by four Afro-tropical mos quito species that vector dengue, malaria, and Rift Valley fever. Herein, we have expanded on this study by investi gating the role of three of the plants, Pithecellobium dulce (Fabaceae), Leonotis nepetifolia (Lamiaceae), and Opuntia fcus-indica (Cactaceae), on the survival, fecundity, and egg viability of the dengue vector Aedes aegypti. Methods: We tested these efects us...


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