Browsing by Author "Van Noort, Simon"

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    Barcoding alien invertebrates and biological control agents in South Africa, with a focus on the natural enemies of Thaumatotibia leucotreta (Meyrick)
    (2025) Pitcher, Tristan; Janion-Scheepers, Charlene; Van Noort, Simon
    Alien invertebrate species and agricultural pests pose economic challenges through impeding crop production and threatening biodiversity in South Africa. Invertebrates are particularly successful invaders owing to their short generation times, high reproductive output, widespread occurrence across terrestrial, freshwater and marine environments, and considerable morphological diversity. The false codling moth, Thaumatotibia leucotreta (Meyrick), is a notable pest in South Africa, as it attacks important export crops such as citrus and stone fruit, greatly reducing returns on these exports, while threatening the country's access to international markets. While several wasp species have been recorded parasitising T. leucotreta, their distribution in South Africa is poorly documented, while only two species have been trialled as biological control agents against the pest. The projected shifts in species distribution patterns due to globalisation and climate change underscore the need for comprehensive baseline genetic and distribution data of alien invertebrate species and biological control agents. Such data are important for mitigating and managing biological invasions. A useful genetic tool in this respect, is DNA barcoding, which uses a short genetic marker to aid in the delimitation of species. However, there is no recent database of barcoded alien invertebrates and biological control agents in South Africa. In addition, thermal physiological traits of invertebrates are useful data for modelling species distributions, especially under climate change. However, current baseline physiological data of important pests and their biological control agents remain limited, negatively impacting our understanding of their present and future distribution patterns. This study aimed to: 1) review the DNA barcoding status of alien invertebrates and biological control agents in South Africa; 2) sample T. leucotreta parasitoid wasps in organic and IPM orchards within the Western Cape; and 3) to determine the critical thermal limits of Trichogrammatoidea cryptophlebiae Nagaraja, an egg parasitoid used as a biological control agent against T. leucotreta, in the laboratory. The review of alien invertebrate species in South Africa identified major gaps in DNA barcoding, particularly among arachnids and platyhelminths (flatworms). While 66.8% of all alien invertebrate species in the South African dataset were accessioned on BOLD (Barcoding of Life Datasystems), only 24.3% of these records represented specimens collected in South Africa. Furthermore, 44.6% of alien invertebrate species records on BOLD were not accompanied by images. This research has identified important gaps in the baseline knowledge of alien invertebrate species, pests, and biological control agents in South Africa. The paucity of South African specimens and image records on BOLD constrains the effectiveness of these records for identification. Despite conducting sampling under ideal conditions, no T. leucotreta parasitoids were sampled in the Western Cape. This absence may be attributed to low parasitoid population densities or suboptimal sampling methodology. The lack of T. leucotreta parasitoids sampled in the Western Cape suggests that natural wasp populations may be insufficient for pest control, supporting the case for augmentative biological control whilst highlighting the need for more intensive sampling and trials of parasitoid wasps as biological control agents. Using thermal tolerance assays, the critical thermal minimum and maximum of T. cryptophlebiae were determined to be 8.15°C ± 0.58°C and 44.50°C ± 0.41°C (mean ± SE), respectively. The critical thermal minimum of T. cryptophlebiae determined in this study exceeds the wasp's lower developmental threshold, indicating that adult wasps are less cold-tolerant than other life stages. These thermal tolerance data provide valuable baseline information for predicting potential distribution shifts of T. cryptophlebiae under climate change scenarios. Overall, this study contributed to baseline data on alien invertebrate, pest and biological control agent species, including T. leucotreta and its parasitoids, in South Africa. These baseline data underscore the need for further research on the distribution and biology of these important species.
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    Megalyridia capensis (Hymenoptera: Megalyridae: Megalyridiini) a relict species endemic to South Africa
    (2009) Van Noort, Simon; Shaw, Scott
    Numerous further specimens of the monotypical megalyrid species Megalyridia capensis Hedqvist have recently been collected from diverse habitats encompassing a distributional range of more than 800 km in South Africa. The male of M. capensisis recorded for the first time. We provide high-quality Numerous further specimens of the monotypical megalyrid species Megalyridia capensis Hedqvist have recently been collected from diverse habitats encompassing a distributional range of more than 800 km in South Africa. The male of M. capensisis recorded for the first time. We provide high-quality images of both sexes and a key to genera of Megalyridae occurring in the Afrotropical region. Online keys are available at: http://www.waspweb. org/Megalyroidea/Megalyridae/Keys/index.htm. The biogeography of this relict species is discussed.
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    Phylogeny and codivergence in the fig-fig wasp mutualism : sycoecine and agaondid fig wasps (Chalcidoidea, Hymenoptera) associated with Ficus section Galoglychia (Moraceae)
    (2008) Underhill, Jenny G; Tolley, Krystal A; Hedderson, Terry A; Van Noort, Simon
    The interaction between figs and figs wasps is idealised as a classic example of coevolution through codivergence and cospeciation. Traditionally, the mutualism has been distinguished by a one-to-one ratio of host-specificity, whereby each species of fig tree (Ficlls, Moraceae) is pollinated by a unique species of fig wasp (Agaonidae, Chalcidoidea, Hymenoptera). Recent studies conclude, however, that extreme host-specificity is no longer as ubiquitous as previously considered. Nevertheless, there are many factors that are thought to constrain host-switching events and maintain, to some degree, the host specificity of both pollinating and non-pollinating fig wasps within the fig wasp community. This dissertation investigates the extent of codivergence between the host fig trees of Ficus section Galoglychia, associated agaonid pollinators and sycoecine non-pollinating fig wasps (Pteromalidae, Chalcidoidea, Hymenoptera) through cophylogenetic analysis.
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    Review of Afrotropical Figitinae (Figitidae, Cynipoidea, Hymenoptera) with the first records of Neralsia and Lonchidia for the region
    (2014) Van Noort, Simon; Buffington, Matthew L; Forshage, Mattias
    The cynipoid subfamily Figitinae is poorly represented in the Afrotropical region with two genera (Figites Latreille and Xyalophora Kieffer) and six species currently known. Here we record an additional two genera (Neralsia Cameron and Lonchidia Thomson) for the region and describe three new species: Neralsia haddocki sp. n.; Xyalophora tedjoansi sp. n.; Xyalophora tintini sp. n. Benoit’s species described in 1956 are synonymized under Figites aciculatus (Benoit, 1956): Figites effossus syn. n.; Figites favonius syn. n.; Figites furvus syn. n.; Figites fraudator syn. n. Identification keys to the figitine genera and species occurring in the Afrotropical region are provided. Online interactive Lucid Phoenix and Lucid matrix keys are available at: http://www.waspweb.org/Cynipoidea/Keys/index.htm
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    Sneaky African fig wasps that oviposit through holes drilled by other species
    (2009) Compton, Stephen G; Van Noort, Simon; McLeish, Michael; Deeble, Mark; Stone, Victoria
    Watshamiella Wiebes species (Hymenoptera: Chalcidoidea: Pteromalidae: Sycoryctinae) were observed to engage, monitor and subsequently use oviposition holes made by other parasitoid fig wasp genera (Apocrypta Coquerel and Sycoryctes Mayr) to oviposit into host figs (Moraceae, Ficus) through the fig wall. They may be inquilines, klepto-parasitoids, or hyper-parasitoids; however, further biological investigations of larval diet are required to establish their life history strategy. Watshamiella species are morphologically robust, with enlarged fore femora and tibia, and aggressively interact with other fig wasps and ants. Our observations contribute towards unravelling the complex suite of behavioural adaptations and interactions involved in the community ecology of the obligate mutualism that exists between fig wasps and their host figs.