Common Yucca (Yucca filamentosa) and Yucca Moth (Tegeticula yuccasella)- A Mutualist Relationship
The relationship between the Yucca plant and the Yucca Moth is the perfect example of how insects and plants need and depend on each other.
Research documents – Seed Predation Due to the Yucca-moth Symbiosis- The American Midland Naturalist | Vol. 112, No. 1 (Jul., 1984), pp. 187-191 (5 pages)states that there are over 40 species of yucca plants and all of them depend on one moth for pollination as the moth depends on its seed for its species’ survival. The yucca plants are not pollinated by wind or other insects like other flowering plants per se, the way the plant is pollinated is by one particular moth- a Yucca Moth.
While this species along with a few others, this moth does not feed and is short-lived. The male and female pretty much have one function in their lives, the male is to mate and the female is to lay eggs. Once the male has mated it has completed its life cycle, and the continuation of its species solely depends on the female, and how she does that is incredible.
She collects pollen!
According to what these research documents explain is that when the female visits the flower she collects pollen from the anthers with these tentacle-like appendages and stores that pollen under her chin. She will use the pollen she collects for a very important purpose. When she is ready to lay eggs, she will fly to different flowers during the cool nighttime hours. She may even fly to another plant entirely.
If there is a flower that has not been taken by another female moth, she will release her eggs into the ovary of the flower, it is unclear how she uses her ovipositor (a tubular organ through which a female insect deposits eggs), whether she makes a hole from the side of the flower’s ovary or climbs on the top of the stigma and creates a hole that way.
Once she lays her eggs, this is when the pollen she collects is put to use, and the only way the yucca plant is pollinated. She will pack some pollen near the stamen to ensure pollination. If pollination is successful, the flower will produce seeds. Those seeds will feed the larvae.
Once the moth’s larvae stage is complete, it will drop to the ground and begin its cocoon life cycle in the dirt below.
Now that I think about it, I wonder if there are other plants that have this mutualistic relationship. Yes, The senita cactus and senita moth. Read it here: Senita Mutualism (uh.edu)
Just to note. If you do explore the flowers to see a yucca moth, please be mindful of them. They have a very short life span and a very important part of their life cycle depends on the existence of their species, as well as the plant itself.
Keeley, Jon E., Sterling C. Keeley, Cheryl C. Swift, and Janet Lee. “Seed Predation Due to the Yucca-Moth Symbiosis.” The American Midland Naturalist 112, no. 1 (1984): 187–91. https://doi.org/10.2307/2425472.
Rau, Phil. “The Yucca Plant, Yucca Filamentosa, and the Yucca Moth, Tegeticula (Pronuba) Yuccasella Riley: An Ecologico-Behavior Study.” Annals of the Missouri Botanical Garden 32, no. 4 (1945): 373–94. https://doi.org/10.2307/2394443.
Bogler, D. J., J. L. Neff, and B. B. Simpson. “Multiple Origins of the Yucca-Yucca Moth Association.” Proceedings of the National Academy of Sciences of the United States of America 92, no. 15 (1995): 6864–67. http://www.jstor.org/stable/2367753.
David M. Althoff, Kari A. Segraves, Evolution of antagonistic and mutualistic traits in the yucca‐yucca moth obligate pollination mutualism, Journal of Evolutionary Biology, 10.1111/jeb.13967, 35, 1, (100-108), (2021).