Genetic and chemical divergence among host races of a socially parasitic ant. Issue 23 (6th November 2018)

• Record Type: Journal Article
• Authors: Torres, Candice W.; Tonione, Maria A.; Ramírez, Santiago R.; Sapp, Joseph R.; Tsutsui, Neil D.
• Is Part Of: Ecology and evolution. Volume 8:Issue 23(2018)
• Page Start: 11385
• Page End: 11398
• Publication Date: 2018-11-06
• Subjects: chemical ecology -- cuticular hydrocarbons -- genetic differentiation -- host race -- host–parasite relationship -- speciation; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.4547
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Host–parasite associations facilitate the action of reciprocal selection and can drive rapid evolutionary change. When multiple host species are available to a single parasite, parallel specialization on different hosts may promote the action of diversifying natural selection and divergence via host race formation. Here, we examine a population of the kidnapper ant ( Polyergus mexicanus ) that is an obligate social parasite of three sympatric ant species: Formica accreta, F. argentea, and F. subaenescens (formerly F. fusca ). Behavioral and ecological observations of P. mexicanus have shown that individual colonies parasitize only one species of host and that new Polyergus queens maintain host fidelity when establishing new colonies. To successfully adapt to a particular host, Polyergus ants may mimic or camouflage themselves with the species‐specific chemical cues (cuticular hydrocarbons) that their hosts use to ascertain colony membership. To investigate the extent of host specialization, we collected both genetic and chemical data from P. mexicanus that parasitize each of the three different Formica species in sympatry. We show that host‐associated genetic structure exists for both maternally inherited mitochondrial DNA data and biparentally inherited microsatellite markers. We also show that P. mexicanus can be distinguished by chemical profile according to host due to partial matching with their host. Our results support the hypothesis that host race formation is occurring among lineages of P. mexicanus that use different Formica hosts. Thus, this system may represent a promising model for illuminating the early steps of divergence, accumulation of reproductive isolation, and speciation. Abstract : Ant colonies are a rich resource for potential parasites, and numerous species have evolved to use them as hosts. Here, we perform genetic and chemical analyses of a socially parasitic ant that kidnaps other ant species and uses them as hosts. We show that sympatric parasite colonies that use particular hosts are genetically differentiated from colonies using other host species, suggesting the formation of host races, and initial stages of speciation.