title: Flower heating following anthesis and the evolution of gall midge pollination in Schisandraceae.
abstract: OBJECTIVE
  Flower heating is known from a few species in 11 of the c. 450 families of flowering plants. Flowers in these families produce heat metabolically and are adapted to beetles or flies as pollinators. Here, we focus on the Schisandraceae, an American/Asian plant family known to exhibit flower heating in some species, but not others, raising the question of the adaptive function of heat production. •
  
  
  METHODS
  We used field observations, experiments, and ancestral trait reconstruction on a molecular phylogeny for Schisandraceae that includes the investigated species. •
  
  
  RESULTS
  At least two Chinese species of Illicium are exclusively pollinated by gall midges that use the flowers as brood sites (not for pollen feeding). Continuous monitoring of flower temperatures revealed that the highest temperatures were attained after the flowers' sexual functions were over, and experiments showed that post-anthetic warming benefited larval development, not fruit development. Midge larvae in flowers with trimmed tepals (and hence a lower temperature) died, but fruit set ratios remained unchanged. Based on the DNA phylogeny, gall midge pollination evolved from general fly/beetle pollination several times in Schisandraceae, with some species adapted to flower-breeding midges, others to pollen-feeding midges. •
  
  
  CONCLUSIONS
  Flower heating may be an ancestral trait in Schisandraceae that became co-opted in species pollinated by flower-breeding midges requiring long-persistent warm chambers for larval development.
authors: Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou 510650, China.
authors: Shi-Xiao
authors: SX
authors: Luo
authors: Shu-Miaw
authors: SM
authors: Chaw
authors: Dianxiang
authors: D
authors: Zhang
authors: Susanne S
authors: SS
authors: Renner