title: Pollination in a patchily distributed lousewort is facilitated by presence of a co-flowering plant due to enhancement of quantity and quality of pollinator visits.
abstract: OBJECTIVE
  Plants surrounded by individuals of other co-flowering species may suffer a reproductive cost from interspecific pollen transfer (IPT). However, differences in floral architecture may reduce or eliminate IPT.
  
  
  METHODS
  A study was made of Pedicularis densispica (lousewort) and its common co-flowering species, Astragalus pastorius, to compare reproductive and pollination success of lousewort plants from pure and mixed patches. Floral architecture and pollinator behaviour on flowers of the two plants were compared along with the composition of stigmatic pollen load of the louseworts. The extent of pollen limitation of plants from pure and mixed patches was also explored through supplemental pollination with self- and outcross pollen (PLs and PLx).
  
  
  RESULTS
  Mixed patches attracted many more nectar-searching individuals of Bombus richardsi. These bumble-bees moved frequently between flowers of the two species. However, they pollinated P. densispica with their dorsum and A. pastorius with their abdomen. This difference in handling almost completely eliminated IPT. Lousewort plants from mixed patches yielded more seeds, and seeds of higher mass and germinability, than those from pure patches. Moreover, louseworts from mixed patches had lower PLs and PLx compared with those from pure patches.
  
  
  CONCLUSIONS
  Differences in floral architecture induced differences in pollinator behaviour that minimized IPT, such that co-flowering plants significantly enhanced quantity and quality of pollinator visits for the lousewort plants in patchy habitat. These findings add to our understanding of the mechanisms of pollination facilitation.
authors.affiliation: Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, The Chinese Academy of Sciences, Wuhan 430074, China.
authors.forename: Chun-Feng
authors.initials: CF
authors.lastname: Yang
authors.forename: Qing-Feng
authors.initials: QF
authors.lastname: Wang
authors.forename: You-Hao
authors.initials: YH
authors.lastname: Guo
mesh_terms: D000818:Animals; D027883:Astragalus Plant / Q000502:physiology*; D001516:Bees; D001522:Behavior, Animal; D035264:Flowers / Q000502:physiology*; D032262:Pedicularis / Q000502:physiology*; D054817:Pollination
keywords: Astragalus pastorius; Pedicularis densispica; bumble-bee; geitonogamous mating; interspecific pollen transfer; lousewort; mechanical isolation; pollen limitation; pollination; pollinator behaviour