During a recent vacation in Port Clinton, OH, my wife and I were enthralled by the captivating bloom display of American Lotus (Nelumbo lutea, family Nelumbonaceae) that we could view from our hotel window. In my opinion, there is nothing else that rises from our waters to rival the allure of this aquatic beauty, except perhaps a plate of fried lake perch or walleye.
American Lotus, Lake Erie – Port Clinton, OH
The fragrant yellowish-white flowers (lutea means yellow) and large, exotic-looking round leaves rise above the water which separates this native from aquatic plants belonging to the water-lily family, Nymphaeaceae. Water-lily leaves float on top of the water unless the plants experience a drop in the water level.
American White Water-Lily (Nymphaea odorata)
There are only two species of lotus worldwide. Our native American lotus ranges throughout the eastern U.S. from the Great Plains to the Atlantic seaboard, from Maine to Florida.
The Sacred Lotus (N. nucifera) is native to eastern Asia and is also called the Indian, Asian, or Pink Lotus. Although the pink flowers are beautiful, this non-native has found its way into parts of the U.S., including Ohio, which is why it’s listed along with other bad characters in the 2nd edition of Ohio Field Guide to Aquatic Invasive Species: https://ohioseagrant.osu.edu/products/dy9gp/ohio-field-guide-to-ais
Sacred Lotus – Butler County Park, OH - 1
Sacred Lotus – Butler County Park, OH - 2
The American lotus, on the other hand, is a celebrated native plant. Indeed, don’t miss tomorrow’s “American Lotus Celebration” held by the Ohio Department of Natural Resources in Cowan Lake State Park. Click this hot link for more details:
Both American lotus and the sacred lotus were once placed in the water-lily family; however, based on DNA sequencing, the lotuses are now placed in their own family and moved to a different order, Proteales. This order also includes the plane family, Platanaceae. This means that the closest relative of the American lotus in the U.S. is the American sycamore (Platanus occidentalis). I hope you were sitting down when you read that sentence!
American lotus colonies spread by seeds and submerged rhizomes. The plants are not free-floating; they are firmly rooted in submerged soil. That's why plants grow around the edges of ponds or in the shallow waters of lake inlets or river backwaters; oxbows are a favored location.
American Lotus Showerhead-Like Seed Pods
The large lotus leaves are coated in epicuticular waxes. I've always appreciated how droplets of rainwater that collect in the leaf centers glisten gem-like in the sun. The leaves and stems have milky sap, which contains alkaloids that have been shown to have anti-bacterial properties as well as other interesting attributes.
American Lotus – Glistening Water
Although I could find no references to the sap containing latex, it certainly behaves like a latex-based compound. This provides great entertainment value.
Lotus Stem Sap – Entertainment Value
The lotus plants provide a healthy habitat for a wide range of micro- and macroorganisms. The large leaves protect immature fish from predators, ducks and other migratory birds utilize the seeds, and the rhizomes are eaten by beavers and muskrats. Native Americans also utilized all parts of the plant for food, from the rhizomes to the leaves to the seeds.
American lotus can be enjoyed in a number of locations around Ohio beyond Lake Cowen. As noted above, you can find American lotus growing in shallow inlets along Lake Erie as well as Tappan Lake in northeast Ohio. I’ve also come across colonies in small ponds in a number of county and city parks.
American Lotus, Lake Erie – East Harbor State Park, OH
American Lotuse – Glenwood Gardens, OH
A Boring Native Moth
Of course, my favorite macroorganism found on both American lotus and sacred lotus in the U.S. is the American Lotus Borer Ostrinia penitalis (Lepidoptera: Crambidae). The moth is closely related to the non-native European Corn Borer (O. nubilalis), with the adults being almost indistinguishable.
American Lotus Borer Leaf Damage
Early instar lotus borer caterpillars are found on the upper leaf where they use silk to pull together two radiating leaf veins, creating a shallow trough-like depression. Individual caterpillars reside within these depressions covered by a dense mat of silk, which presumably prevents them from falling or being washed into the water and provides camouflage against predators. The ruse is not always effective, as there are reports of redwing blackbirds shredding leaves in search of the caterpillars.
American Lotus Borer Feeding Structure
American Lotus Borer - Caterpillar Hidden Beneath Silk
The caterpillars feed beneath their webbed abodes and also venture forth, apparently mostly at night, to feed on the surrounding leaf surface. During this time, the caterpillars remain anchored to the leaf with silk, which is an adaptation to their aquatic environment that prevents them from being washed away by waves.
American Lotus Borer Middle Instar
American Lotus Borer Late Instar
True to their common name, as the larvae mature, they eventually change their feeding habits to become borers. The caterpillars burrow into the leaf petiole where the petiole attaches to the leaf and feed by tunneling down the petiole.
American Lotus Borer – Caterpillars in a Stem
Their stem-bringing activity isn't just confined to the leaf petioles. The caterpillars also tunnel through the flower stems to eventually find their way into the seed heads. This is where the second-generation larvae pupate to spend the winter.
American Lotus Borer Seed Pod Damage
There are records of the borer causing serious damage to all parts of its native and non-native lotus hosts, including significantly reducing seed production. Indeed, I observed severe leaf damage to the lotus in Cowan Lake. However, other than physically removing the caterpillars from the leaves and stems, there are no other effective controls.
American Lotus Borer Leaf Damage
Fortunately, as with any native insect, populations tend to rise and fall dramatically from year to year, so the borer seldom causes significant long-term damage to a colony of American lotus. It appears that established American lotus colonies have the ability to recover from periodical onslaughts by its caterpillar.
Selected References
Coates, B. S., & Abel, C. A. (2014). The mitochondrial genome of the American lotus borer, Ostrinia penitalis (Lepidoptera: Crambidae). Mitochondrial DNA Part A, 27(3), 1938–1939. https://doi.org/10.3109/19401736.2014.971296
Coates, B. S., & Abel, C. A. (2019). Differentiation of European corn borer (Lepidoptera: Crambidae) and American lotus borer (Lepidoptera: Crambidae), Ostrinia penitalis, from north American field collections. Journal of Economic Entomology, 112(4), 2007-2011.
https://doi.org/10.1093/jee/toz078
Dieringer, G., Leticia Cabrera, R., & Mottaleb, M. (2014). Ecological relationship between floral thermogenesis and pollination in Nelumbo lutea (Nelumbonaceae). American Journal of Botany, 101(2), 357-364.
https://doi.org/10.3732/ajb.1300370
Hall, T. F., & Penfound, W. T. (1944). The biology of the American lotus, Nelumbo lutea (Wild.) Pers. American Midland Naturalist, 744-758.
https://doi.org/10.2307/2421417
Islam, M. R., Zhang, Y., Li, Z. Z., Liu, H., Chen, J. M., & Yang, X. Y. (2020). Genetic diversity, population structure, and historical gene flow of Nelumbo lutea in USA using microsatellite markers. Aquatic Botany, 160, 103162.
https://doi.org/10.1016/j.aquabot.2019.103162
Li, Y., Svetlana, P., Yao, J., & Li, C. (2014). A review on the taxonomic, evolutionary and phytogeographic studies of the lotus plant (Nelumbonaceae: Nelumbo). Acta Geologica Sinica‐English Edition, 88(4), 1252-1261.
https://doi.org/10.1111/1755-6724.12287
Lu, B., Nzei, J. M., Li, Z., Chen, J., Yang, X., & Perleberg, D. J. (2023). Population genetics of Nelumbo lutea (American lotus) near its northwestern range limit. Aquatic Botany, 188, 103673.
https://doi.org/10.1016/j.aquabot.2023.103673
Ryon, M. G., Jett, R. T., McCracken, M. K., Morris, G. W., Roy, W. K., Fortner, A. M., ... & Riazi, A. S. (2013). Technique for rapid establishment of American lotus in remediation efforts. Native Plants Journal, 14(1), 33-38.
https://doi.org/10.3368/npj.14.1.33
Sayre, J. (2004). Propagation Protocol for American Lotus ( Nelumbo lutea Willd.). Native Plants Journal 5(1), 14-17.
https://dx.doi.org/10.1353/npj.2004.0017
Swan, D. C. (2010). The North American Lotus (Nelumbo lutea Willd Pers.) - Sacred Food of the Osage People. Ethnobotany Research and Applications, 8, 249–253. Retrieved from https://ethnobotanyjournal.org/index.php/era/article/view/496
Turner, A. M., Cholak, E. J., & Groner, M. (2010). Expanding American Lotus and Dissolved Oxygen Concentrations of a Shallow Lake. The American Midland Naturalist, 164(1), 1-8. https://proxy.lib.ohio-state.edu/login?url=https://www.proquest.com/scholarly-journals/expanding-american-lotus-dissolved-oxygen/docview/610794694/se-2