International Carnivorous Plant Society

Carnivorous Plant Newsletter Archive


Can Venus flytraps be triggered to close by raindrops?

Stephen E. Williams and Bill Scholl

Carniv. Pl. Newslett. 50(2):60-65
Published 11 May 2021

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Dionaea muscipula traps, in a natural setting, are sometimes triggered to close without capturing prey. In the Florida panhandle, in dry weather, time-lapse photographs show the frequency of closure without capture to be 2.1 closures/% of active-traps/day. A sudden burst of intense rain can increase this by two to three orders of magnitude for a brief time. Frequencies of 15.5 closures/% of active-traps/hour and 148 closures/% of active-traps/hour have been measured. The large increase in closures occurs when rain first starts, because the most exposed and most sensitive traps are triggered early, leaving traps in a more sheltered position and those with a less sensitive response open. Only 6 to 12% of the traps in the field of view were closed by intense rain. Even rain so heavy that the traps were submerged in water left most of the traps open. Gentle rain can close traps, but this is not a common event. The necessity of two or more stimuli to close a trap accounts for traps general lack of responsiveness to raindrops in light rainfall. Traps observed to be closed by raindrops began reopening in an average of 4.5 hours and full reopening averaged 15.8 hours. Since partially open traps are capable of capturing prey, the average trap closed by rain is effective at trapping in about 12 hours. Rainfall is only a minor factor interfering with traps' ability to catch prey.

Keywords: Venus flytaps, Dionaea muscipula, raindrop, trigger, traps, Florida

Article Citation

Stephen E. Williams and Bill Scholl. 2021. Can Venus flytraps be triggered to close by raindrops?. Carniv. Pl. Newslett. 50(2):60-65.

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