Premium
Mechanical reproductive isolation via divergent genital morphology between Carabus insulicola and C. esakii with implications in species coexistence
Author(s) -
Kubota Kôhei,
Miyazaki Kôji,
Ebihara Shiho,
Takami Yasuoki
Publication year - 2013
Publication title -
population ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 59
eISSN - 1438-390X
pISSN - 1438-3896
DOI - 10.1007/s10144-012-0335-4
Subject(s) - biology , reproductive isolation , parapatric speciation , sympatric speciation , subgenus , interspecific competition , zoology , evolutionary biology , ecology , genus , gene flow , genetics , population , gene , genetic variation , demography , sociology
The mechanical isolation hypothesis predicts that physical incompatibility between divergent reproductive morphologies hinders hybridization between populations. However, evidence for this hypothesis remains scarce. We examined this hypothesis using two parapatric carabid beetles, Carabus insulicola and C . esakii , which are of the subgenus Ohomopterus and exhibit a species‐specific genital lock‐and‐key system. Our interspecific crossing experiment revealed that incompatibility of genital morphologies served as a strong postmating‐prezygotic isolation barrier. This isolation was asymmetric: a decrease in female fitness was more costly in the cross with greater genitalic incompatibility between a C. esakii female and a C . insulicola male. These two species share a limited sympatric area, but the mechanism responsible for their coexistence is unclear given no evidence of premating isolation via male mate choice. A comparison of the present results with those of previous studies that quantified reproductive isolation between Ohomopterus species suggest that strong mechanical isolation via genitalic incompatibility plays a major role in species isolation, but that it may be less important in species coexistence.