Plantwatch: The plant that shoots toxic liquid – and the insects trying to beat it

The bursera plant's leaves can squirt chemicals 1.5 metres, but over millions of years, some beetles have learned to disarm it

Insects get a nasty surprise if they try biting into the leaves of bursera shrubs and trees: they use a sort of squirt gun to shoot a high-pressure stream of liquid resin at the attacking insect. This liquid is thoroughly repellent and poisonous, but for good measure the resins in the liquid can turn solid when exposed to air and seal a small insect in a tomb.

The squirt gun stores its chemicals in a network of canals in the leaf. When an insect bites a leaf canal, the liquid squirts out as far as 1.5 metres, drenching a small insect in deadly secretions. Larger insects that survive the attack suffer reduced growth and life expectancy.