Browsing by Author "Slabbert, Eleonore Louise"

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    Potential ecosystem services and disservices of arthropods associated with Cyclopia (Honeybush) species.
    (Stellenbosch : Stellenbosch University, 2016-03) Slabbert, Eleonore Louise; Addison, Pia; Veldtman, Ruan; Malgas, Rhoda R.; Stellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.
    ENGLISH ABSTRACT: Cyclopia species, commonly known as honeybush, are endemic to the Eastern and Western Cape of South Africa. Honeybush has historically been used as a tea, but has more recently been proven to have medicinal use properties. Honeybush biomass and extracts are used in the functional foods and cosmetics sectors both locally, and overseas. The growing demand for honeybush tea calls for further commercialization of the industry and a shift away from the predominantly (70%) wild harvested supply. The current study aimed to address the lack of baseline knowledge on insects associated with honeybush and serves to identify arthropods of importance for arthropod-mediated ecosystem services and disservices associated with honeybush cultivation. The study was conducted on wild and cultivated Cyclopia species (C. maculata and C. genistoides) in the Overberg region. Sampling methods for recording honeybush phenology and monitoring insects were used on a monthly schedule, from April 2014 to April 2015. Phenology observations were conducted using qualitative methods recording seasonal change and plant feeding damage by insects. Arthropod monitoring techniques included suction sampling, sweep netting, pan traps and delta traps. Focal insect taxa (Coleoptera, Hemiptera, Thysanoptera, Lepidoptera and Hymenoptera) were sorted and identified to family and morphospecies level where applicable. Families and morphospecies were classified into functional feeding guilds relevant to honeybush biomass production. Functional guild classification was used to assess the relative predator-prey and parasotid-host composition of the arthropod assemblages associated with honeybush. Qualitative phenology observations of wild C. maculata and cultivated C. genistoides indicated a high level of resemblance in seasonality of phenophase stages. The arthropod assemblage contained a diversity of families per functional feeding group relevant to biomass production, namely phytophagous, zoophagous and omnivorous taxa. Of the phytophagous arthropods a cohort of endopterygote and exopterygote taxa, among others, are noted as potential pest insects. A diverse collection of natural enemies (parasitoids and predators), from several Coleoptera and Hymenoptera families, were also abundant in wild and cultivated honeybush stands. Of the diverse natural enemy complex, parasitoids formed the predominant component with potential as valuable natural biological control agents. Disturbance caused by land management practices altered the functional composition of the arthropod assemblage significantly. This combined with isolation from the natural vegetation, due to cultivation, had a negative synergistic effect on the natural enemy complex (parasitoid and predatory wasps) in cultivated honeybush stands. The current research results highlight the importance of incorporating agroecological principles on fine- and landscape-scales for sustainable and ecologically sound honeybush cultivation. Research outcomes can be applied towards the development of land management practices, promoting a sustainable productive agroecosystem, for the commercialization of Cyclopia species. Considering the current biodiversity crisis and threatened ecosystem status of several honeybush species an ecologically-based approach is strongly recommended. Furthermore these findings form the basis for further research on the value of natural biological control agents for the integrated pest management of cultivated honeybush.