Carnivorous Plants and Their Prey

(12). When an insect or other invertebrate lands on the trap, it becomes ensnared in a quagmire
of mucus. As the animal struggles to free itself, it becomes even more coated in the mucus which
leads to complete incapacitation and eventual suffocation (1, 12). Drosera sundews illustrate the
method of prey capture and consumption in sticky flypaper traps with an added ‘twist’. Sundews
have their leaves modified into tentacle-like structures covered with mucus-laden hairs. The hairs
are tipped with an attractive droplet of nectar that draws insects in (10, 54). Movement of prey
insects along the hairs initiates electrical impulses along the tentacles and triggers surrounding
hairs to fold in on the struggling victim (16, 54). The curled tentacles provide additional contact
points for digestive glands to break down the prey (12). Digestive enzymes produced by the plant
begin the process of tissue degradation at the site of prey capture (12, 54). In genera like
Pinguicula, leaves do not coil around the victim; instead, the prey is simply immobilized in the
mucus (12).
Spring Traps
While pitfall and sticky flypaper traps are quite widespread across genera, the most
common type of trap is the spring-trap design (15). This is due to the large number of
bladderworts (Utricularia spp.) – the greatest number of species of carnivorous plants – with such
trapping mechanisms. The spring-trap carnivorous plants are housed in two families, the
Droseraceae and Lentibulariaceae. The monospecific Dionea and Aldrovanda are placed in the
Droseraceae while the Lentibulariaceae contains about 280 species of Utricularia, one species of
Biovularia, and two species of Polypompholyx (1, 15, 53). Biovularia species are sometimes
included in the genus Utricularia (55).
Spring-traps differ from genus to genus and include a variety of forms as diverse as the
“bear trap” design of the Venus flytrap (Dionea muscipula) or the waterwheel plant (Aldrovanda
vesiculosa) and the suction traps of the aquatic Utricularia species (12, 15). The variance in trap
construction launches a disparity in trap nomenclature. For example, spring-traps are sometimes
referred to as active steel-traps with Dionaea and Aldrovanda or mousetraps in the Biovularia,
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