Insect pollination for most of angiosperm evolutionary history

Area of Science:

• Evolutionary Biology
• Botany
• Ecology

Background:

• Most flowering plants (angiosperms) rely on insect pollination today.
• However, wind, water, and vertebrate pollination also occur, with insect pollination potentially being ancestral.
• Previous assessments of angiosperm pollination evolution have not covered the full phylogeny.

Purpose of the Study:

• To reconstruct the ancestral pollination mode of angiosperms.
• To quantify the timing and environmental factors associated with pollination shifts throughout angiosperm evolution.
• To provide an overview of pollination macroevolution in angiosperms.

Main Methods:

• Utilized a robust, dated phylogeny encompassing all angiosperm families.
• Incorporated species-level sampling with data from 1160 species.
• Modeled the evolution of pollination systems using phylogenetic comparative methods.

Main Results:

• Angiosperms were ancestrally insect-pollinated, with insects dominating pollination for approximately 86% of their evolutionary history.
• Wind pollination evolved at least 42 times, with rare reversals to animal pollination.
• Vertebrate pollination evolved at least 39 times from insect-pollinated ancestors, with at least 26 reversals; its probability correlates with habitat openness and distance from the equator.

Conclusions:

• Insect pollination has a long and deep history in angiosperms, underscoring the enduring importance of insect-pollinator interactions.
• The evolution of wind pollination is strongly associated with environmental factors like habitat openness.
• Pollination syndromes in angiosperms demonstrate significant evolutionary lability, particularly between insect and vertebrate pollination modes.