The geographical pollinator mosaic

Pollinators are distributed unevenly in time and space. Indeed, like all animals, pollinators have restricted ranges, which are often determined by both physical factors, such as altitude, temperature, and rainfall, and by biotic factors, such as vegetation structure and availability of flowering plants (Chapters 6 and 15). The landscape in which plants evolve presents a geographical mosaic of pollinators that is hard to visualize, but is no less important for plant evolution than the...

Petal colour

Petal colour provides a visual cue that stimulates pollinator sensory systems and that selectively attracts certain types of pollinators (Grant 1949 Stebbins 1974 Melendez-Ackerman and Campbell 1998 Hodges et al. 2002). As a corollary, shifts in petal colour can promote speciation through reduced gene flow between colour morphs in association with concurrent changes in pollinator identity (Schemske and Bradshaw 1999 Hodges et al. 2002 Bradshaw and Schemske 2003). Nevertheless, anthocyanins, the...

References

Floral specialization without trade-offs optimal corolla flare in contrasting pollination environments. Ecology, 85, 2560-9. Armbruster WS (1985). Patterns of character divergence and the evolution of reproductive ecotypes of Dalechampia scandens (Euphorbiaceae). Evolution 39, 733-52. Armbruster WS, Edwards ME, and Debevic EM (1994). Floral character displacement generates assemblage structure of western Australian triggerplants (Styli-dium). Ecology, 75, 315-29. Ashton PS,...

Direct effects of plant size on fitness gains

Plant size can affect fitness directly, so that returns from a given absolute amount of resources differ for small and large plants Fig. 3.5 . For instance, in a wind-pollinated plant, pollen released from a tall individual may disperse farther and be more successful than pollen from a short individual. Direct effects may also occur in some animal-pollinated plants, because pollinators may prefer taller plants among neighbours Ishii 2004 . With direct effects of plant size, fitness returns per...

Asexual reproduction a neglected mechanism of reproductive assurance

Lloyd 1979, 1980b, 1988 and others have noted repeatedly the evolutionary communalities between self-fertilization and the various forms of asexual reproduction. Like selfing, asexuality has evolved repeatedly in plants. Asexual seed production apomixis has been described in gt 400 flowering plant taxa representing gt 40 families Carman 1997 , and vegetative or clonal asexual reproduction occurs in up to 80 of plant species Klimes et al. 1997 . Yet, compared with the large body of work on the...

Reproductive assurance and selffertilization theoretical context

Despite the obvious advantages of uniparental reproduction, most flowering plants predominantly outcross and relatively few reproduce exclusively via self-fertilization Goodwillie et al. 2005 . Inbreeding depression, the reduced vigour of inbred compared with outbred individuals, is one of the few selective factors strong enough to oppose the automatic selection of selfing Charlesworth and Charlesworth 1987 . Early mathematical models pitting the two-fold gene transmission advantage of selfing...