Plantwatch: A flower’s male parts carry all sorts of surprises for pollinators

Triggerplants in particular live up to their name with a rapid response when touch-sensitive stamen are nudged

Flowers are surprisingly touchy, especially their male parts, the stamens, with hundreds of plant species performing touch-sensitive stamen movements that can be endlessly repeated. Insects visiting Berberis and Mahonia flowers to feed on nectar get slapped by stamens that bend over and smother pollen on to the insect's face or tongue. This unwelcome intrusion scares the insect into making only a short visit, so the flower avoids wasting its nectar and pollen. The insect then finds another flower where it brushes the pollen off on receptive female organs and cross-pollinates the flower.

An insect landing on the flowers of the orchid Catasetum gets a violent reception - whacked by a pair of sticky pollen bags shooting out at such great speed the insect gets knocked out of the flower with the pollen bags glued to its body.