A Garden with a Secret
Leafy Jaws
A stink bug, a common pest to both gardeners and home owners, follows the scent of nectar from a nearby plant. The beetle climbs over rigid green leaves that have long, spike-like projections along their outer edges. The stink bug awkwardly waddles between two leaves; unknowingly, it brushes one of its legs against a tiny hair on the inside of the leaf. Charging forward, it strikes yet another hair. Snap! In a fraction of second, it has become locked inside leafy jaws. On the beetle's own search for food, it accidentally has become the next meal for a Venus Flytrap!
The flytrap is covered in “mouths,” each of which is made up of two leaf lobes hinged together at their base. Once the beetle brushed its leg against the first hair on the inner portion of the leaf, the plant began a countdown. When the stink bug triggered another hair in under 30 seconds, the plant lobes snapped shut. The spike or teeth-like projections on the edges of the lobes acted like a set of jaws to lock the beetle inside. As the beetle continued to struggle to free itself, it triggered more hairs, thus sending the message to the flytrap to start digestion. Had the beetle been able to avoid triggering the third hair, the flytrap mouth would have eventually reopened in about 24 hours. However, the increased sensation to the plant assured it that it had caught prey and not a stray raindrop or twig.
The mouth eventually seals shut and digestive juices fill the inner cavity, turning the beetle into a nutrient-rich soup for the leaves to absorb. In this way, the flytrap acts as a mouth, stomach, and intestines, all in one unit. After 5-12 days, depending on the insect, the mouth re-opens, leaving behind a skeleton that blows away, making the plant ready for its next meal. Flytraps are found natively in the Carolinas of the US where soils are moist, but lack adequate nutrition for flytraps, so they depend on insects like spiders, ants, beetles, and flies to supplement their diet.
Dew Drops of Death
A jewel-like plant glistens in the sunlight. Green stalk-like leaves arise from its base, each one covered in little red tentacles sticking out perfectly straight with glassy balls at their ends. It looks like morning dew or rain has settled along the tips of the plant. An ant begins to climb up one of the leaves, attracted to the sugary beads on the tentacles. As the ant approaches its meal, its legs get unexpectedly tangled in a sticky substance. What appeared to be water is actually a glue-like liquid belonging to a Cape Sundew.
The more the ant struggles to free itself, the more it gets stuck. The motion of the ant signals to the plant that it has caught something, and glands recognize it as prey. Within minutes, the plant starts to curl nearby tentacles towards the ant to increase contact with its meal. Much like its relative, the Venus Flytrap, the sundew produces digestive enzymes to break down its meal, which can take anywhere from five days to two weeks, at which point the plant uncurls its tentacles to reveal an insect skeleton that can easily fall away, making it ready to attract another unfortunate insect.
Pitcher Perfect Ending
A row of elegant vase-like leaves stand tall. At the top of the plants, the leaves form an umbrella-like shade cover. Nectar available from the underside of the leafy lid attracts a fly. As it lands, the fly struggles to get a footing on the leaf because of very fine downward-facing hairs on the inner surface. As the fly struggles to land, it slides down the slippery sides of the vase-like basin below, where it lands in a pool of liquid containing digestive juices. The Tropical Pitcher plant doesn't have to rely on motion to start eating its meal. Instead it lures prey in with the promise of a meal, then when the insects struggle to get a grip, they accidentally slide down into the plant's “green stomach.” The fly will quickly drown, and the pitcher plant will dissolve and then absorb nutrients from the fly's body. Eventually, the fly skeleton will become part of a growing graveyard at the bottom of the plant.
One species of pitcher plant known as the endangered Attenborough's pitcher plant is the largest meat-eating plant. It can grow almost five feet in height with pitchers that are almost a foot across at their opening. At that size it can capture and eat mice and other small animals!
Carnivorous Plants and Botanic Gardens
Our journey through a very spooky garden was inspired by our good fortune in catching the carnivorous plant show during the first weekend in October held at Tower Hill Botanic Garden in Bolyston, Massachusetts. Tower Hill started out as the Worcester County Horticultural Society. It is the third oldest active horticultural society in the US, dating back to 1840. Over the years, it has evolved to a 171-acre property in central MA, where it is a year-round destination for a variety of elaborate gardens that welcome visitors to explore the finest plants for cultivation in New England and beyond.
References:
Encyclopedia Britannica, Nepenthes, Accessed 10/12/21 from: https://www.britannica.com/plant/Nepenthes
National Park Service, US Department of the Interior, Carnivorous Plants, Accessed 10/12/21 from: https://www.nps.gov/bith/learn/nature/carnivorous-plants.htm
Parry, Wynne. (2011) How the Venus Flytrap Kills and Digests Its Prey, Live Science, Accessed 10/12/21 from: https://www.livescience.com/15910-venus-flytrap-carnivorous.html
Shipman, Matt. (2018) Venus Flytraps Don't Eat the Insects that Pollinate Them, North Carolina State University, Accessed 10/12/21 from: https://news.ncsu.edu/2018/02/venus-flytraps-2018/
The National Wildlife Federation, Sundews, Accessed 10/12/21 from: https://www.nwf.org/Educational-Resources/Wildlife-Guide/Plants-and-Fungi/Sundews
The National Wildlife Federation, Venus Flytrap, Accessed 10/12/21 from: https://www.nwf.org/Educational-Resources/Wildlife-Guide/Plants-and-Fungi/Venus-Flytrap
United States Fish and Wildlife Service, US Department of the Interior, Venus Flytrap, Accessed 10/12/21 from: https://www.fws.gov/southeast/wildlife/plants/venus-flytrap/
University of California, Santa Barbara, UCSB ScienceLine, How do Venus fly trap digest insects and does it matter what type of insect? Accessed 10/12/21 from: http://scienceline.ucsb.edu/getkey.php?key=4884
Youngsteadt, E., Irwin, R. E., Fowler, A., Bertone, M. A., Giacomini, S. J., Kunz, M., Suiter, D., and Sorenson, C. E. (2018). Venus Flytrap Rarely Traps Its Pollinators. The American Naturalist, 191(4), 539-546. doi:10.1086/696124