Sexual conflict, antagonistic coevolution and mating system evolution in the annual plant Collinsia heterophylla
Åsa Lankinen
dept. Plant Ecology and Systematics, Lund University, Sweden
Species of Collinsia (Plantaginaceae) show extensive variation in mating system; this variation is associated with variation in floral morphology and development, and with timing of self-pollination. Large-flowered, more out-crossing species also tend to delay stigma receptivity. This may enhance pollen competition either between donors or between self pollen. Competition between self pollen may be of particular importance in species with mixed mating system because it can lead to reduced inbreeding depression. On the other hand, possessing this trait may result in natural selection favouring pollen that manipulate onset of stigma receptivity to secure paternity at the expense of the female reproductive function. Our recent work in large-flowered Collinsia heterophylla indeed suggests that there is a sexual conflict over timing of stigma receptivity, as crosses that succeeded early during floral development resulted in a cost of lowered seed production. Furthermore, crosses performed within and between populations revealed that this cost disappeared when foreign pollen was used, a pattern consistent with a history of sexually antagonistic coevolution within populations.
Åsa Lankinen
dept. Plant Ecology and Systematics, Lund University, Sweden
Species of Collinsia (Plantaginaceae) show extensive variation in mating system; this variation is associated with variation in floral morphology and development, and with timing of self-pollination. Large-flowered, more out-crossing species also tend to delay stigma receptivity. This may enhance pollen competition either between donors or between self pollen. Competition between self pollen may be of particular importance in species with mixed mating system because it can lead to reduced inbreeding depression. On the other hand, possessing this trait may result in natural selection favouring pollen that manipulate onset of stigma receptivity to secure paternity at the expense of the female reproductive function. Our recent work in large-flowered Collinsia heterophylla indeed suggests that there is a sexual conflict over timing of stigma receptivity, as crosses that succeeded early during floral development resulted in a cost of lowered seed production. Furthermore, crosses performed within and between populations revealed that this cost disappeared when foreign pollen was used, a pattern consistent with a history of sexually antagonistic coevolution within populations.
