Wind Pollination, Self‐incompatibility, and Altitudinal Shifts in Pollination Systems in the High Andean Genus Espeletia (Asteraceae)

Abstract

Altitudinal changes in breeding and pollination systems of tropical montane plants were studied in 13 species of Espeletia growing in the Venezuelan Andes from 2,000 to 4,300 m. Hand pollination tests showed that all species were strongly self‐incompatible. The four species found only above 4,000 m had up to 10% median seed set in self‐pollinated heads, which was significantly higher than the lower elevation species. Nine species were insect‐pollinated, with large bees the major pollinator group. An endemic páramo hummingbird, Oxypogon guerinii, was an important visitor of E. schultzii in three populations examined. Experimental bagging experiments showed that the four high elevation species were wind‐pollinated, further evidenced by the lack of pollinator visits and markedly different capitulum morphologies. Open‐pollinated seed set in two wind‐pollinated species, E. spicata and E. timotensis, was strongly dependent on the population's flowering density, which varied significantly from year to year. The shift from insect to wind pollination in Espeletia can be related to the low pollinator availability at high elevations in the Andes, protection of the capitula from snow and daily frosts, and the extremely long flowering periods of individual heads.

Genetic insights into the historical distribution of Polylepis pauta (Rosaceae) in the northeastern Cordillera Oriental of Ecuador

“…Similarly, the dispersal distance of Polylepis spp. pollen has not been specifically studied; nonetheless, wind pollination and dispersal are likely to become more important with increasing altitude in tropical montane floras (Smith and Young 1987;Berry and Calvo 1989). Although contemporary long-distance pollen flow could act to reduce genetic differentiation among populations, the very low genetic differentiation and the lack of a strong isolation by distance pattern make it likely that the current patchy distribution of P. pauta in this landscape resulted from fragmentation that may have occurred during the lifetime of some of the adult trees.…”

“…All species are thought to be wind pollinated (SalgadoLabouriau et al 1977;Berry and Calvo 1989;Fjeldså and Kessler 1996) and wind dispersed (Van Schaik et al 1993;Vélez et al 1998). Polylepis pauta, the tallest species within the genus (15-27 m), is characterized by thin, dark orange bark that sheds in bands.…”

Biological characteristics of an invasive south African species

“…According to Seavey and Carter (1994), no case has been reported in which all the individuals of a population are self-sterile, although complete self-sterility has been found in individual plants. This trait is found in other species (Berry and Calvo 1989;Whisler and Snow 1992;Reinartz and Les 1994).…”

“…We used the critera of Berry and Calvo (1989) to determine self-incompatibility, in S. inaequidens. It amounts to less than 20% of seed set in self versus cross-pollination.…”

The effects of pollen limitation on population dynamics of snow lotus (Saussurea medusa and S. laniceps, Asteraceae): Threatened Tibetan medicinal plants of the eastern Himalayas

“…Low visitation by pollinators may result in lower pollen receipt and lower seed production for plants. Alternatively, many high elevation plant species are selfcompatible and/or can autogamously self-pollinate (Berry and Calvo 1989), and are thus less dependent on pollinators.…”