Facts or theories or happenings overheard on the radio

In China, there is a region now devoid of honeybees but full of pear trees. Farmers there pollinate the pears by hand, collecting pollen from the anthers, drying it, then climbing into the trees and brushing the stamens with the equivalent of pollen-covered feather dusters.

Rats emit a high-frequency sound when tickled that might be analogous to laughter.

The world's coolest parasite: "A nematode (Myrmeconema neotropicum) that infects canopy ants (Cephalotes atratus) causes the black coloured gasters of workers to turn red. The parasite also alters the behaviour of the ant, and makes them carry their gasters high. The conspicuous red gasters are mistaken by birds for ripe fruits such as Hyeronima alchorneoides and eaten. The droppings of the bird are collected by other ants and fed to their young leading to the further spread of the nematode." - Yes, I am citing Wikipedia's article on ants.