Coevolutionary causes and consequences of high-fidelity mimicry by a specialist brood parasite
| dc.contributor.advisor | Spottiswoode, Claire N | |
| dc.contributor.advisor | Jamie, Gabriel A | |
| dc.contributor.author | Lund, Jess | |
| dc.date.accessioned | 2022-03-04T08:05:17Z | |
| dc.date.available | 2022-03-04T08:05:17Z | |
| dc.date.issued | 2021 | |
| dc.date.updated | 2022-03-03T13:11:45Z | |
| dc.description.abstract | Mimicry is often invoked as a classic demonstration of the power of natural selection. However, mimicry systems are diverse and the accuracy of mimicry, or mimetic fidelity, varies from crude to near-perfect. There is growing evidence that low-fidelity mimicry is the norm, with cases of high-fidelity mimicry being rarer. This is particularly evident in avian interspecific brood parasites, which are birds that lay their eggs in the nests of other species, or ‘hosts'. A possible rare example of a “perfect mimic” is the African cuckoo Cuculus gularis (a specialist parasite of fork-tailed drongos Dicrurus adsimilis) which, to the human eye, exhibits some of the most sophisticated mimicry seen in a brood parasite-host system. In this work, I quantify the degree of mimetic fidelity in this system and investigate its consequences on the two antagonists, using experimental, observational and genetic data I collected in the field in Zambia. In Chapter 1 I first define perfect mimicry, and explore how mimetic fidelity can be quantified. I then review the factors responsible for the variability in mimetic fidelity among different mimicry systems. In Chapter 2 I use quantitative measures of egg colour and pattern, from models that approximate avian vision, to show that mimicry of drongo eggs by African cuckoos is near-perfect. I subsequently use field experiments and simulations to show that a high degree of interclutch variation (egg ‘signatures') means that drongos still have the upper hand in the arms race against this near-perfect mimic. In Chapter 3 I investigate the genetic architecture of perfect mimicry by comparing cuckoo egg phenotypes to their mitochondrial DNA haplotypes, providing evidence that the African cuckoo likely shows bi-parental inheritance of egg phenotype. Together these results highlight the effectiveness of egg signatures as a defence against brood parasites, even when mimicry shows high accuracy and precision, and underline the role of mechanistic factors in enabling high-fidelity mimicry to evolve. | |
| dc.identifier.apacitation | Lund, J. (2021). <i>Coevolutionary causes and consequences of high-fidelity mimicry by a specialist brood parasite</i>. (). ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/35903 | en_ZA |
| dc.identifier.chicagocitation | Lund, Jess. <i>"Coevolutionary causes and consequences of high-fidelity mimicry by a specialist brood parasite."</i> ., ,Faculty of Science ,Department of Biological Sciences, 2021. http://hdl.handle.net/11427/35903 | en_ZA |
| dc.identifier.citation | Lund, J. 2021. Coevolutionary causes and consequences of high-fidelity mimicry by a specialist brood parasite. . ,Faculty of Science ,Department of Biological Sciences. http://hdl.handle.net/11427/35903 | en_ZA |
| dc.identifier.ris | TY - Master Thesis AU - Lund, Jess AB - Mimicry is often invoked as a classic demonstration of the power of natural selection. However, mimicry systems are diverse and the accuracy of mimicry, or mimetic fidelity, varies from crude to near-perfect. There is growing evidence that low-fidelity mimicry is the norm, with cases of high-fidelity mimicry being rarer. This is particularly evident in avian interspecific brood parasites, which are birds that lay their eggs in the nests of other species, or ‘hosts'. A possible rare example of a “perfect mimic” is the African cuckoo Cuculus gularis (a specialist parasite of fork-tailed drongos Dicrurus adsimilis) which, to the human eye, exhibits some of the most sophisticated mimicry seen in a brood parasite-host system. In this work, I quantify the degree of mimetic fidelity in this system and investigate its consequences on the two antagonists, using experimental, observational and genetic data I collected in the field in Zambia. In Chapter 1 I first define perfect mimicry, and explore how mimetic fidelity can be quantified. I then review the factors responsible for the variability in mimetic fidelity among different mimicry systems. In Chapter 2 I use quantitative measures of egg colour and pattern, from models that approximate avian vision, to show that mimicry of drongo eggs by African cuckoos is near-perfect. I subsequently use field experiments and simulations to show that a high degree of interclutch variation (egg ‘signatures') means that drongos still have the upper hand in the arms race against this near-perfect mimic. In Chapter 3 I investigate the genetic architecture of perfect mimicry by comparing cuckoo egg phenotypes to their mitochondrial DNA haplotypes, providing evidence that the African cuckoo likely shows bi-parental inheritance of egg phenotype. Together these results highlight the effectiveness of egg signatures as a defence against brood parasites, even when mimicry shows high accuracy and precision, and underline the role of mechanistic factors in enabling high-fidelity mimicry to evolve. DA - 2021_ DB - OpenUCT DP - University of Cape Town KW - Biological Sciences LK - https://open.uct.ac.za PY - 2021 T1 - Coevolutionary causes and consequences of high-fidelity mimicry by a specialist brood parasite TI - Coevolutionary causes and consequences of high-fidelity mimicry by a specialist brood parasite UR - http://hdl.handle.net/11427/35903 ER - | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11427/35903 | |
| dc.identifier.vancouvercitation | Lund J. Coevolutionary causes and consequences of high-fidelity mimicry by a specialist brood parasite. []. ,Faculty of Science ,Department of Biological Sciences, 2021 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/35903 | en_ZA |
| dc.language.rfc3066 | eng | |
| dc.publisher.department | Department of Biological Sciences | |
| dc.publisher.faculty | Faculty of Science | |
| dc.subject | Biological Sciences | |
| dc.title | Coevolutionary causes and consequences of high-fidelity mimicry by a specialist brood parasite | |
| dc.type | Master Thesis | |
| dc.type.qualificationlevel | Masters | |
| dc.type.qualificationlevel | MSc |