Bee Diversity and some Aspects of their Ecological Interactions with Plants in a Successional Tropical Community

This study aimed at establishing bee diversity and some aspects of their interactions with plants along a forest regeneration gradient in Kakamega Forest. To determine the bee diversity, bee samples were collected with the help of sweep nets along belt transects for a period of two years, that is, May 2002 to April 2004. In addition, more data on bee species was collected from the existing past records and bee collections from National Museums of Kenya. In total, 243 species of bees represented in four families, of which 234 were sampled in Buyangu Nature Reserve were recorded during the study. These families included Apidae, Halictidae, Megachilidae and Colletidae. In addition, 40 families of representing 189 species of plants were found to support the bee community. The most important plant families included Acanthaceae, Asteraceae and Papilionaceae. A high degree of resource sharing based on niche overlap results was observed between the highly eusocial and the dominant solitary bee species, although the eusocial bees showed the largest niche breadth. Similarly, generalization was more pronounced among the eusocial bees as compared to solitary bees. The results from this study agreed with the expected trend of increased diversity in secondary forests as compared to mature forests. In contrast, generalization was found to increase with forest maturity. In conclusion, the study clearly indicates that bees require a diversity of microhabitats. Secondary forests and surrounding farming areas offer the best refugia sites for bees. On the other hand, the bees cannot survive without the forest for it offers nesting sites and abundant floral resources especially during the dry season when there are no flowers in the open areas. Based on the current results, Kakamega Forest stands out as one of the best bee hot-spots in East Africa. The study advocates further research in pollination biology of wild plants especially on rare plants given that a high level of generalization was documented among the eusocial and solitary bees but little is known on plants’ perspective. Finally, I wish to recommend further research on whether natural forest regeneration process should be altered in some forest patches in order to maintain some secondary forests

Characterization of Pathogenic Fungi Infecting Citrullus lanatus in Different Agroecological Regions of Embu County, Kenya

Watermelon (Citrullus lanatus) fruit is nutritious and a profitable cash crop. Its production in Kenya however has dropped from 379.36K metric tonnes to 173.70K metric tonnes in the last five years; attributed to pests, diseases and unpredictable climatic conditions. Study done between July and November, 2018 isolated and characterized fungi associated with watermelon determining their diversity and occurence frequency in Embu County, Kenya. Necrotic fruits and leaves (n=160) were sampled from random farms (n=16). Fungi isolated and  cultured on PDA.; characterized by morphological and molecular method. ANOVA was used to detect fungal prevalence differences among sites. Fusarium oxysporum was most prevelent with 73% frequency, Aspergillus niger (32%). Penicilliun crustosum and Fusarium brachygibbosum at 31%  each. Least prevalent was Trichoderma asperellum (1%). Significant differences (F= 23.365, p=0.05, df=13), were observed among agroecological sites except for Fusarium oxysporium and F. brachygibbosum. Majority of fungi identified were of significant economic importance

Bee diversity and floral resources along a disturbance gradient in Kaya Muhaka forest and surrounding farmlands of coastal Kenya

Bees provide important pollination services that maintain native plant populations and ecosystem resilience, which is critical to the conservation of the rich and endemic biodiversity of Kaya forests along the Kenyan Coast. This study examined bee composition and floral resources from the forest core to the surrounding farmlands around Kaya Muhaka forest. In total, 755 individual bees, representing 41 species from three families were recorded: Apidae, Halictidae and Megachilidae. Overall, Apidae were the most abundant with a proportion of 76% of the total bee individuals, Halictidae at 14% and Megachilidae at 10%. Bee composition was similar between forest edge and crop fields as compared to forest core and fallow farmlands. We found a significant decrease in bee diversity with increasing distance from the forest to the surrounding farming area. A high abundance of bees was recorded in fallow farmland, which could be explained by the high abundance of floral resources in the habitat. We found floral resources richness to significantly affect bee species richness. These findings are important for understanding the effects of land use change on insect pollinators and their degree of resilience in disturbed habitat

Aspects determining the risk of pesticides to wild bees: risk profiles for focal crops on three continents

In order to conduct a proper risk assessment of pesticides to bees, information is needed in three areas: the toxicity of the pesticide;the probability of bee exposure to that pesticide; andthe population dynamics of the bee species in question.Information was collected on such factors affecting pesticide risk to (primarily wild) bees in several crops in Brazil, Kenya and The Netherlands. These data were used to construct ‘risk profiles’ of pesticide use for bees in the studied cropping systems. Data gaps were identified and potential risks of pesticides to bees were compared between the crops. Initially, risk profiling aims to better identify gaps in our present knowledge. In the longer term, the established risk profiles may provide structured inputs into risk assessment models for wild and managed bees, and lead to recommendations for specific risk mitigation measures. Keywords: pesticide, exposure, risk, wild bees, risk profil

Forest Fragmentation and Selective Logging Have Inconsistent Effects on Multiple Animal-Mediated Ecosystem Processes in a Tropical Forest

Forest fragmentation and selective logging are two main drivers of global environmental change and modify biodiversity and environmental conditions in many tropical forests. The consequences of these changes for the functioning of tropical forest ecosystems have rarely been explored in a comprehensive approach. In a Kenyan rainforest, we studied six animal-mediated ecosystem processes and recorded species richness and community composition of all animal taxa involved in these processes. We used linear models and a formal meta-analysis to test whether forest fragmentation and selective logging affected ecosystem processes and biodiversity and used structural equation models to disentangle direct from biodiversity-related indirect effects of human disturbance on multiple ecosystem processes. Fragmentation increased decomposition and reduced antbird predation, while selective logging consistently increased pollination, seed dispersal and army-ant raiding. Fragmentation modified species richness or community composition of five taxa, whereas selective logging did not affect any component of biodiversity. Changes in the abundance of functionally important species were related to lower predation by antbirds and higher decomposition rates in small forest fragments. The positive effects of selective logging on bee pollination, bird seed dispersal and army-ant raiding were direct, i.e. not related to changes in biodiversity, and were probably due to behavioural changes of these highly mobile animal taxa. We conclude that animal-mediated ecosystem processes respond in distinct ways to different types of human disturbance in Kakamega Forest. Our findings suggest that forest fragmentation affects ecosystem processes indirectly by changes in biodiversity, whereas selective logging influences processes directly by modifying local environmental conditions and resource distributions. The positive to neutral effects of selective logging on ecosystem processes show that the functionality of tropical forests can be maintained in moderately disturbed forest fragments. Conservation concepts for tropical forests should thus include not only remaining pristine forests but also functionally viable forest remnants

Biocultural approaches to pollinator conservation

Pollinators underpin sustainable livelihoods that link ecosystems, spiritual and cultural values, and customary governance systems with indigenous peoples and local communities (IPLC) across the world. Biocultural diversity is a short-hand term for this great variety of people-nature interlinkages that have developed over time in specific ecosystems. Biocultural approaches to conservation explicitly build on the conservation practices inherent in sustaining these livelihoods. We used the Conceptual Framework of the Intergovernmental Platform on Biodiversity and Ecosystem Services to analyse the biocultural approaches to pollinator conservation by indigenous peoples and local communities globally. The analysis identified biocultural approaches to pollinators across all six elements of the Conceptual Framework, with conservation-related practices occurring in sixty countries, in all continents except Antarctica. Practices of IPLC that are significant for biocultural approaches to pollinator conservation can be grouped into three categories: the practice of valuing diversity and fostering biocultural diversity; landscape management practices; and diversified farming systems. Particular IPLCs may use some or all of these practices. Policies that recognise customary tenure over traditional lands, strengthen Indigenous and Community Conserved Areas, promote heritage listing and support diversified farming within a food sovereignty approach, are among several identified that strengthen biocultural approaches to pollinator conservation, and thereby deliver mutual benefits for pollinators and people

Investigating the Viral Ecology of Global Bee Communities with High-Throughput Metagenomics

Bee viral ecology is a fascinating emerging area of research: viruses exert a range of effects on their hosts, exacerbate the impacts of other environmental stressors, and, importantly, are readily shared across multiple bee species in a community. However, our understanding of bee viral communities is limited, as it is primarily derived from studies of North American and European Apis mellifera populations. Here, we examined viruses in populations of A. mellifera and 11 other bee species from 9 countries, across 5 continents and Oceania. We developed a novel pipeline to rapidly, inexpensively, and robustly screen for bee viruses. This pipeline includes purification of encapsulated RNA/DNA viruses, sequence-independent amplification, high throughput sequencing, integrated assembly of contigs, and filtering to identify contigs specifically corresponding to viral sequences. We identified sequences corresponding to (+)ssRNA, (-)ssRNA, dsRNA, and ssDNA viruses. Overall, we found 127 contigs corresponding to novel viruses (i.e. previously not observed in bees), with 29 represented by \u3e0.1% of the reads in a given sample. These viruses and viral families were distributed across multiple regions and species. This study provides a robust pipeline for metagenomics analysis of viruses, and greatly expands our understanding of the diversity of viruses found in bee communities

CropPol: a dynamic, open and global database on crop pollination

Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA). This article is protected by copyright. All rights reserved