Genetic admixture predicts parasite intensity: evidence for increased hybrid performance in Darwin's tree finches. Issue 4 (3rd April 2019)

• Record Type: Journal Article
• Authors: Peters, Katharina J.; Evans, Christine; Aguirre, J. David; Kleindorfer, Sonia
• Is Part Of: Royal Society open science. Volume 6:Issue 4(2019)
• Publication Date: 2019-04-03
• Subjects: hybrid fitness -- adaptive capacity -- Philornis downsi -- Galápagos -- parasites -- Camarhynchus; Science -- Periodicals; 500
• DOI: 10.1098/rsos.181616
• Languages: English
• ISSNs: 2054-5703

Abstract

Abstract : Hybridization can increase adaptive potential when enhanced genetic diversity or novel genetic combinations confer a fitness advantage, such as in the evolution of anti-parasitic mechanisms. Island systems are especially susceptible to invasive parasites due to the lack of defence mechanisms that usually coevolve in long-standing host–parasite relationships. We test if host genetic admixture affects parasite numbers in a novel host–parasite association on the Galápagos Islands. Specifically, we compare the number of Philornis downsi in nests with offspring sired by Darwin's small tree finch ( Camarhynchus parvulus ), Darwin's medium tree finch ( C. pauper ) and hybrids of these two species. The number of P. downsi decreased with an increasing genetic admixture of the attending male, and nests of hybrid males had approximately 50% fewer parasites than C. parvulus nests, and approximately 60% fewer parasites than C. pauper nests. This finding indicates that hybridization in this system could be favoured by selection and reveal a mechanism to combat an invasive parasite.