Selection against hybridization can cause mating traits to diverge between species in sympatry via reproductive character displacement （RCD）. Additionally, selection against interspecific fighting can cause aggressi...Selection against hybridization can cause mating traits to diverge between species in sympatry via reproductive character displacement （RCD）. Additionally, selection against interspecific fighting can cause aggressive traits to diverge between sympatric species via agonistic character displacement （ACD）. By directly affecting conspecific recognition traits, RCD and ACD between species can also incidentally cause divergence in mating and fighting traits among populations within a species [termed cascade RCD （CRCD） and cascade ACD]. Here, we demonstrate patterns consistent with male-driven RCD and ACD in 2 groups of darters （orangethroat darter clade Ceasia and rainbow darter Etheostoma caeruleum）. In both groups, males that occur in sympatry （between Ceasia and E. caeruleum） have higher levels of preference for mating and fighting with conspecifics over heterospecifics than do males from allopatry. This is consistent with RCD and ACD. We also found patterns consistent with CRCD and cascade ACD among species of Ceasia. Ceasia males that are sympatric to E. caeruleum （but allopatric to one another） also have heightened preferences for mat- ing and fighting with conspecific versus heterospecific Ceasia. In contrast, Ceasia males that are allopatric to E. caeruleum readily mate and fight with heterospecific Ceasia. We suggest that RCD and ACD between Ceasia and E. caeruleum has incidentally led to divergence in mating and fighting traits among Ceasia species. This study is unique in that male preferences evolve via both RCD （male preference for conspecific females） and ACD （male preference to fight conspecific males） which leads to subsequent divergence among allopatric lineages.展开更多
基金This work was supported by the Cooperative State Research, Education, and Extension Service, US Department of Agriculture, under project number ILLU 875-952, the National Science Foundation （DEB 0953716 and IOS 1701676）, and the University of IlLinois. The treatment of animals was approved by the Institutional Animal Care and Use Committee under protocol No. 14097.
文摘Selection against hybridization can cause mating traits to diverge between species in sympatry via reproductive character displacement （RCD）. Additionally, selection against interspecific fighting can cause aggressive traits to diverge between sympatric species via agonistic character displacement （ACD）. By directly affecting conspecific recognition traits, RCD and ACD between species can also incidentally cause divergence in mating and fighting traits among populations within a species [termed cascade RCD （CRCD） and cascade ACD]. Here, we demonstrate patterns consistent with male-driven RCD and ACD in 2 groups of darters （orangethroat darter clade Ceasia and rainbow darter Etheostoma caeruleum）. In both groups, males that occur in sympatry （between Ceasia and E. caeruleum） have higher levels of preference for mating and fighting with conspecifics over heterospecifics than do males from allopatry. This is consistent with RCD and ACD. We also found patterns consistent with CRCD and cascade ACD among species of Ceasia. Ceasia males that are sympatric to E. caeruleum （but allopatric to one another） also have heightened preferences for mat- ing and fighting with conspecific versus heterospecific Ceasia. In contrast, Ceasia males that are allopatric to E. caeruleum readily mate and fight with heterospecific Ceasia. We suggest that RCD and ACD between Ceasia and E. caeruleum has incidentally led to divergence in mating and fighting traits among Ceasia species. This study is unique in that male preferences evolve via both RCD （male preference for conspecific females） and ACD （male preference to fight conspecific males） which leads to subsequent divergence among allopatric lineages.
