Environmental & Physical Sciences

Environmental & Physical Sciences Research Papers/Topics

Impact of net houses on the natural regulation of the populations of Trialeurodes vaporariorum (Homoptera: Aleyrodidae) and Tuta absoluta (Lepidoptera: Gelechiidae), two major tomato pests in

Abstract: The abandonment of insecticide treatments to achieve sustainable crop production calls for a combination of methods to obtain satisfactory pest control. To this end, net houses and biological control are two promising methods, though we suspected that most natural enemies are blocked outside the net houses. In Kenya, tomato crops are particularly threatened by Trialeurodes vaporariorum (Westwood 1856) and Tuta absoluta (Meyrick, 1917) that are targets of most insecticide treatments...

Estimating the Demographic Parameters of Tuta absoluta (Lepidoptera: Gelechiidae) Using Temperature-Dependent Development Models and Their Validation under Fluctuating Temperature

Abstract: The tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is an invasive pest that devastates the production of tomatoes and other solanaceous vegetables. Since its transAtlantic invasion in 2006, T. absoluta has spread and established in many countries across the AfroEurasian Supercontinent, causing huge yield losses. This study aimed to determine the relationship between temperature and the life history traits of T. absoluta and provide the thermal thresholds for d...

Prioritization of invasive alien species with the potential to threaten agriculture and biodiversity in Kenya through horizon scanning

Abstract: Invasive alien species (IAS) rank among the most significant drivers of species extinction and ecosystem degradation resulting in significant impacts on socio-economic development. The recent exponential spread of IAS in most of Africa is attributed to poor border biosecurity due to porous borders that have failed to prevent initial introductions. In addition, countries lack adequate information about potential invasions and have limited capacity to reduce the risk of invasions. Ho...

Measuring and modelling crop yield losses due to invasive insect pests under climate change

Abstract: Climate change and agriculture are strongly correlated, and the fast pace of climate change will have impacts on agroecosystems and crop productivity. This review summarizes potential impacts of rising temperatures and atmospheric CO2 concentrations on insect pest-crop interactions and provides two-way approaches for integrating these impacts into crop models for sustainable pest management strategies designing. Rising temperatures and CO2 levels affect insect physiology, accelerat...

In situ nitrogen mineralization and nutrient release by soil amended with black soldier fly frass fertilizer

Abstract: Although black soldier fly frass fertilizer (BSFFF) is effective on crop performance, information on nitrogen (N) mineralization and nutrient release capacity of soils amended with BSFFF is lacking. This study utilized field incubation experiments to investigate the ammonification, nitrification, microbial populations, and quantities of nutrients released by soils amended with BSFFF and commercial organic fertilizer (SAFI) for a period equivalent to two maize cropping seasons. For ...

Tissue Specificity in Social Context-DependentlysozymeExpression in Bumblebees

Abstract: Group living at high densities may result in the enhanced transmission of pathogens.Social insects are obligate group-living species, which often also exhibit high relatedness and frequentsocial interactions amongst individuals, resulting in a high risk of disease spread. Social species seemto exhibit immune systems that provide colonies of social insects with a certain level of flexibility foradjustment of immune activity according to the risk of disease spread. In bumblebees,Bomb...

Trapping of Aethina tumida Murray (Coleoptera: Nitidulidae) from Apis mellifera L. (Hymenoptera: Apidae) Colonies with an In-Hive Baited Trap

Abstract: The effectiveness of two lures for trapping the small hive beetle, Aethina tumida, by means of in-hive traps was tested by Þeld trials in apiaries located in Florida, Delaware, and Pennsylvania during 2003Ð2005. Both lures included a mixture (pollen dough) consisting of bee pollen and commercial pollen substitute formulated with or without glycerol and honey. Before it was used in the traps, the dough was conditioned either by the feeding of adult small hive beetles or by inocula...

Nestmate Recognition and the Role of Cuticular Hydrocarbons in the African Termite Raiding Ant Pachycondyla analis

Abstract: Cuticular hydrocarbons (CHCs) are used for chemical communication among nestmates in many ant species, and they may play a role in the discrimination of nestmates and non-nestmates. Using the mandible opening response (MOR) bioassay, we tested the response of the African termite raiding ant, Pachycondyla analis, to CHC extracts of nestmates and non-nestmates. The ants were able to distinguish control chemical cues, from nestmate CHCs, and from non-nestmate CHCs, and, based on a CHC...

Body size as a proxy of probing time and visitation rates on cucumber by two African stingless bees increase fruit quality and seed quantity

Abstract: Pollinators are of essential importance for sustainable agriculture. However, pollination efficiency depends on interacting factors such as pollinator behaviour and morphology. We compared the effect of probing time length and visit frequency of two distinct body size African stingless bee species (Meliponula bocandei, Dactylurina schmidti) as alternative pollinators to Apis mellifera scutellata on greenhouse cultivated cucumber. We found differences in morphometric characteristics...

An expert system for insect pest population dynamics prediction

Abstract: Avocado (Persea americana) production is increasing in Kenya, with both small and largeholder farming for domestic and export markets. However, one of main challenges that limit production is infestation by insect pests, notably the oriential fruit fly Bactocera dorsalis and Ceratitis spp. fruit flies, which cause direct crop losses and are indirectly responsible for non-tariff trade barriers due to stringent export requirements. Data on weekly pest trap counts were collected betwe...

Supplementing Blood Diet With Plant Nectar Enhances Egg Fertility in Stomoxys calcitrans

Abstract: Stomoxys calcitrans (stable fly) is a cosmopolitan biting fly of both medical and veterinary importance. Unlike blood-feeding-related behavior of stable fly, its plant feeding, the fitness value, and the S. calcitrans–plant interaction are less understood. Here we show based on two chloroplast DNA genes, ribulose bisphosphate carboxylase large chain (rbcL) and the intergenic spacer gene trnH-psbA, that field-collected male and female stable flies fed on various plant species. We ...

Beneficial sterols in selected edible insects and their associated antibacterial activities

Abstract: Edible insects are increasingly gaining popularity as research reveals multiple benefits. However, the rediscovery of natural products from insects as medicinal agents has received limited attention. This study aimed at evaluating the diversity of sterols in extracts of nine edible insects and potential antibacterial activities. Dichloromethane extracts of these insects were analyzed using gas chromatography–mass spectrometry to identify important sterols, followed by evaluation ...

Insect diversity is a good indicator of biodiversity status in Africa

Abstract: Reliable metrics to monitor human impacts on biodiversity are essential for informing conservation policy. As insects are indicators of global change, whose declines profoundly affect ecosystems, insect diversity may predict biodiversity status. Here we present an unbiased and straightforward biodiversity status metric based on insect diversity (richness) and landscape naturalness. Insect diversity was estimated using spatially explicit earth observation data and insect species ass...

Leveraging machine learning tools and algorithms for analysis of fruit fly morphometrics

Abstract: Analysis of landmark-based morphometric measurements taken on body parts of insects have been a useful taxonomic approach alongside DNA barcoding in insect identification. Statistical analysis of morphometrics have largely been dominated by traditional methods and approaches such as principal component analysis (PCA), canonical variate analysis (CVA) and discriminant analysis (DA). However, advancement in computing power creates a paradigm shift to apply modern tools such as machin...

Localization and tissue tropism of the symbiont Microsporidia MB in the germ line and somatic tissues of Anopheles arabiensis

Abstract: The Anopheles symbiont, Microsporidia MB, is maternally inherited and has a strong malaria transmission-blocking phenotype in Anopheles arabiensis. Microsporidia MB is also vertically transmitted, sexually transmitted, and avirulent. These characteristics are expected to promote its spread through mosquito populations, enhancing the potential of Microsporidia MB as a candidate for the development of a symbiont-mediated malaria transmission-blocking strategy. We found that the patte...


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