Philip C. Stevenson
University of Greenwich
Publications 165
Tephrosia vogelii is a plant species chemically characterized by the presence of entomotoxic rotenoids and used widely across Africa as a botanical pesticide. Phytochemical analysis was conducted to establish the presence and abundance of the bioactive principles in this species across three countries in East Africa: Tanzania, Kenya, and Malawi. Analysis of methanolic extracts of foliar parts of T. vogelii revealed the occurrence of two distinct chemotypes that were separated by the presence of ...
#1Sara G. Prado (NCSU: North Carolina State University)H-Index: 5
#2Jaime A. Collazo (NCSU: North Carolina State University)H-Index: 23
Last.Rebecca E. Irwin (NCSU: North Carolina State University)H-Index: 36
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Floral traits and rewards are important in mediating interactions between plants and pollinators. Agricultural management practices can affect abiotic factors known to influence floral traits; however, our understanding of the links between agricultural practices and floral trait expression is still poorly understood. Variation in floral morphological, nectar, and pollen traits of two important agricultural species, Coffea arabica and C. canephora, was assessed under different agricultural pract...
Non-crop vegetation around farmland can be valuable habitats for enhancing ecosystem services but little is known of the importance of field margins in supporting natural enemies of insect pests in tropical agriculture. This study was conducted in smallholder bean fields in three elevation zones to assess the importance of field margin vegetation to natural enemy populations and movement to the bean crop for biological pest control. The pests and natural enemies were assessed using different col...
#1Prisila A. Mkenda (CSU: Charles Sturt University)
Last.Victoria C. Woolley (University of Greenwich)
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Parasitoids are among the most frequently reported natural enemies of insect pests, particularly aphids. The efficacy of parasitoids as biocontrol agents is influenced by biotic and abiotic factors. For example, hyperparasitoids can reduce the abundance of the primary parasitoids as well as modify their behavior. A field study was conducted at three contrasting elevations on Mount Kilimanjaro, Tanzania, to identify the parasitoids of aphids in smallholder bean farming agroecosystems. Sentinel ap...
#1Sarah E. J. ArnoldH-Index: 11
#2David HallH-Index: 35
Last.Dudley I. FarmanH-Index: 13
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Most plant species depend upon insect pollination services, including many cash and subsistence crops. Plants compete to attract those insects using visual cues and floral odor which pollinators associate with a reward. The cacao tree, Theobroma cacao, has a highly specialized floral morphology permitting pollination primarily by Ceratopogonid midges. However, these insects do not depend upon cacao flowers for their life cycle, and can use other sugar sources. To understand how floral cues media...
#1Julie K. Davis (UMass: University of Massachusetts Amherst)
#2Luis A. Aguirre (UMass: University of Massachusetts Amherst)H-Index: 1
Last.Lynn S. Adler (UMass: University of Massachusetts Amherst)H-Index: 29
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#1Hauke Koch (Royal Botanic Gardens)H-Index: 15
#2James Woodward (University of Bath)H-Index: 1
Last.Philip C. Stevenson (University of Greenwich)H-Index: 33
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Summary Plant phytochemicals can act as natural “medicines” for animals against parasites [ 1 , 2 , 3 ]. Some nectar metabolites, for example, reduce parasite infections in bees [ 4 , 5 , 6 , 7 ]. Declining plant diversity through anthropogenic landscape change [ 8 , 9 , 10 , 11 ] could reduce the availability of medicinal nectar plants for pollinators, exacerbating their decline [ 12 ]. Existing studies are, however, limited by (1) a lack of mechanistic insights into how phytochemicals affect p...
3 CitationsSource
The plant kingdom produces an extraordinary diversity of secondary metabolites and the majority of the literature supports a defensive ecological role for them, particularly against invertebrate herbivores (antagonists). Plants also produce secondary compounds in floral nectar and pollen and these are often similar to those produced for defense against invertebrates elsewhere in the plant. This is largely because the chemical armoury within a single plant species is typically restricted to a few...
#1Filemon ElisanteH-Index: 1
Last.Philip C. Stevenson (University of Greenwich)H-Index: 33
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Abstract Agro-ecological intensification (AEI) harnesses natural processes, such as pollination, that support sustainable crop production and can buffer against future food security risks. However, the transition from conventional agriculture, which relies on inputs that can damage natural ecosystem processes, to more sustainable food production under AEI, is knowledge-intensive. Here, we investigated knowledge gaps among smallholder farmers about pollinators and field margins in a bean agri-sys...
1 CitationsSource