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Leaf lengths of different Nymphaea mexicana genotypes (N. mexicana (n = 15) vs. hybrids (n = 10)) at invaded sites across South Africa where Bagous longulus was either absent (coloured white) or present (coloured grey). At each site for each genotype, the lengths of five leaves were measured. Hence, the number of replicates for each treatment were lumped together as follows: hybrids without B. longulus = 5 leaf measurements × 7 sites; hybrids with B. longulus = 5 × 4, N. mexicana without B. longulus = 5 × 11, N. mexicana with B. longulus = 5 × 3. The boxes represent upper and lower quartiles and median values; whiskers represent the highest and lowest values at 1.5 times the interquartile range. Outliers are marked as separate dots.
Source publication
Classical biological control aims to suppress alien invasive plant populations by introducing host-specific natural enemies from the native range. This relies on the assumption that invasive plant populations in the invaded range benefit from the release of natural enemies. Pre-release surveys in the invaded range are a useful way to determine if e...
Context in source publication
Context 1
... of the sites had similar leaf sizes, but two sites, namely King's Beach Skate Park (9.78 cm ± 2.43) and Knysna Estate (9.14 cm ± 1.21), had considerably smaller leaf sizes. As a general observed trend, N. mexicana sites where B. longulus was absent had longer leaves on average (mean ± SD) (19.2 ± 3.05 cm) compared to N. mexicana sites where B. longulus was present (13.8 ± 6.58 cm) (Figure 4). This did not apply at the ten hybrid sites, where mean leaf length was similar whether B. longulus was absent (19.7 ± 2.83 cm) or present (21.4 ± 3.40 cm). ...
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Blue lotus, also known as Nymphaea caerulea (Nymphaeaceae), is a water lily found globally in lakes and rivers. With its long history of use in Egyptian culture, blue lotus has been associated with spiritual rituals and health benefits. Nowadays, blue lotus is still consumed as a tea or tincture to induce relaxation and heightened spiritual awarene...
Citations
... Research to develop a biological control programme for N. mexicana and its hybrids began in 2016, and exploratory surveys and prioritisation of potential agents were conducted in the southeastern United States in 2018 (Reid et al. 2020). As a continuation of this research, pre-release surveys were conducted in South Africa between 2020 and 2022 (Reid et al. 2023b). During these pre-release surveys, a native weevil, Bagous longulus Gyllenhal (Curculionidae: Coleoptera), was found feeding and completing its lifecycle on N. mexicana at three sites: one in the Eastern Cape, another in the Western Cape, and the third in KwaZulu-Natal (Reid et al. 2023b). ...
... As a continuation of this research, pre-release surveys were conducted in South Africa between 2020 and 2022 (Reid et al. 2023b). During these pre-release surveys, a native weevil, Bagous longulus Gyllenhal (Curculionidae: Coleoptera), was found feeding and completing its lifecycle on N. mexicana at three sites: one in the Eastern Cape, another in the Western Cape, and the third in KwaZulu-Natal (Reid et al. 2023b). This species, originally known as Pseudobagous longulus (Gyllenhal), is commonly recorded in still or slow-flowing waters in South Africa, Mozambique, Zimbabwe, Botswana and Namibia (Riaan Stals, pers. ...
... Release trials in the other three provinces would confirm the ability of B. longulus to survive in these conditions on N. mexicana, if introduced, even though they were not found in these regions naturally. Such trials would be particularly important in Gauteng (Highveld) where there are several sites invaded by N. mexicana (Reid et al. 2023b) and where the success of other biological control programmes has been limited because of difficulties with introduced agents surviving frosts and cold winters (Coetzee et al. 2011;May and Coetzee 2013;Hill and Coetzee 2017). Indeed, temperature records from experiments conducted at the Waainek Research Facility indicate the ability of the weevil to survive at high air temperatures (>50 °C: Reid 2023), but less information is available about its ability to survive at lower temperatures. ...
