Background Protocarnivorous plants How they trap insects How they evolved

“Plants that derive some or most of their nutrients (but not energy) from trapping and consuming animals, typically insects and other arthropods”. Acidic bogs, rock outcroppings Around 625 species that are true carnivores

Lack ability to directly digest or absorb nutrients from prey Rely on bacteria or internal food webs Darlingtonia californica  Relies on symbiotic bacteria and protozoa

Five trapping mechanisms: Pitfall traps (pitcher plants) Flypaper traps Snap traps Bladder traps Lobster-pot traps

Rolled leaves with enzymes or bacteria in a pool of liquid (phytotelmata) at base Insects attracted by nectar “bribes” Sides are slippery Some have downward pointing hairs Other mechanisms to trap prey – false exits

Utilise mucilage – polar glycoprotein used as glue Secreted by glands on leaf Can be projected (Drosera capensis), or flat (Pinguicula gigantea) Leaves curl around prey to stop escape – thigmotrophic growth  Drosera burmanii can bend 180° in ~ 1min

Leaves divided into two lobes, hinged along the middle Trigger hairs in the lobes sensitive to touch Action potential to midrib Ions pumped out creating osmotic gradient Cells collapse, lobes under tension, snap shut Continuous stimulation keeps lobes shut, encourages growth

Bladder Traps: Exclusive to genus Utricularia (bladderworts) Ions pumped out of bladders Small hinged opening releases vacum Lobster-pot Traps: Easy to enter chamber Escape hindered by bristles, or hard to find exit Prey forced to move down chamber Water movement

Hairy-leaf theory: All traps are based on hairy leaves and folding Hairs trap water droplets, insects drown in water Bacteria decompose, nutrients absorbed into leaves More water held, selective advantage  pitfall traps Bladder traps originate from aquatic plants with pitfall traps