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Developmental plasticity of Harmonia axyridis a test of the relationship between melanisation and performance
Thesis (MSc)--Stellenbosch University, 2019.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2019
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| _version_ | 1867613832769175552 |
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| access_status_str | Open Access |
| author | Kutama, Mulalo Dianah |
| author2 | Clusella Trullas, Susana |
| author_browse | Clusella Trullas, Susana Kutama, Mulalo Dianah |
| author_facet | Clusella Trullas, Susana Kutama, Mulalo Dianah |
| author_sort | Kutama, Mulalo Dianah |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc)--Stellenbosch University, 2019. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/106970 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:42:24.259Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2019 |
| publishDateRange | 2019 |
| publishDateSort | 2019 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/106970 Developmental plasticity of Harmonia axyridis a test of the relationship between melanisation and performance Kutama, Mulalo Dianah Clusella Trullas, Susana Minnaar, Ingrid Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology. Melanins Animal pigments Animals -- Color -- Environmental aspects Insects -- Effect of temperature on Harmonia axyridis -- Ecology Temperature -- Physiological effect Body temperature -- Regulations Insects -- Evolution Variation (Biology) Ecological genetics UCTD Thesis (MSc)--Stellenbosch University, 2019. ENGLISH ABSTRACT: The synthesis of the pigment melanin in insects involves complex pathways and has been shown to play a role in multiple functions such as camouflage, sexual signalling, immunity, warning colouration and thermal adaptation. Melanin expression in the adult phenotype resulting from the temperature experienced during development is likely to play a role in thermoregulation, although other benefits may exist. Given that the production of melanin can be energetically costly, some authors suggest that it could have negative fitness effects or trade-offs. On the other hand, melanisation may co-vary with performance traits as several studies demonstrate a positive relationship between melanisation and immunity. Here, I undertook a series of laboratory experiments to assess whether temperature-induced melanisation of the globally invasive ladybird Harmonia axyridis f. succinea (Pallas) is related to performance (energetic maintenance costs and flight) and test if melanin production leads to a decline or an increase of performance. Differences in melanisation were induced by rearing larvae to adult emergence in two fluctuating temperature regimes: cold (average: ~18°C) and warm (~28°C). The extent of pigmentation of the adult elytra, the resting metabolic rate (RMR) and flight performance (distance travelled and speed) of mature adults were determined. I found that cold-reared beetles were darker than warm-reared beetles but melanisation varied greatly within temperature treatments, especially for females originating from the warm-rearing regime. For cold-reared beetles and RMR tested at 30°C, I found complex interactions of size, sex and melanisation predicting RMR. In addition, complex interactions affecting the distance travelled suggested lower performance with size in more melanic beetles. In the warm-rearing treatment, darker beetles had lower RMR at 20°C and 35°C (for males) than paler beetles with interactive effects of mass and sex and overall, darker beetles flew more slowly than paler beetles. These results suggest that melanisation leads to trade-offs with performance, at least when beetles are reared at warm temperatures. These findings contribute to an improved understanding of developmental plasticity and the potential costs associated with plasticity of melanisation in this species. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Masters 2019-11-26T11:23:27Z 2019-12-11T06:41:00Z 2023-01-04T03:00:09Z 2019-12 Thesis http://hdl.handle.net/10019.1/106970 en_ZA Stellenbosch University vii, 55 pages : illustrations (some color) application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Melanins Animal pigments Animals -- Color -- Environmental aspects Insects -- Effect of temperature on Harmonia axyridis -- Ecology Temperature -- Physiological effect Body temperature -- Regulations Insects -- Evolution Variation (Biology) Ecological genetics UCTD Kutama, Mulalo Dianah Developmental plasticity of Harmonia axyridis a test of the relationship between melanisation and performance |
| title | Developmental plasticity of Harmonia axyridis a test of the relationship between melanisation and performance |
| title_full | Developmental plasticity of Harmonia axyridis a test of the relationship between melanisation and performance |
| title_fullStr | Developmental plasticity of Harmonia axyridis a test of the relationship between melanisation and performance |
| title_full_unstemmed | Developmental plasticity of Harmonia axyridis a test of the relationship between melanisation and performance |
| title_short | Developmental plasticity of Harmonia axyridis a test of the relationship between melanisation and performance |
| title_sort | developmental plasticity of harmonia axyridis a test of the relationship between melanisation and performance |
| topic | Melanins Animal pigments Animals -- Color -- Environmental aspects Insects -- Effect of temperature on Harmonia axyridis -- Ecology Temperature -- Physiological effect Body temperature -- Regulations Insects -- Evolution Variation (Biology) Ecological genetics UCTD |
| url | http://hdl.handle.net/10019.1/106970 |
| work_keys_str_mv | AT kutamamulalodianah developmentalplasticityofharmoniaaxyridisatestoftherelationshipbetweenmelanisationandperformance |