Evolution of spiders to take advantage of essential oils
It is well known that some plants have evolved secondary metabolites, including essential oils, to help them deal with environmental threats. A new hypothesis has emerged that certain animals have also evolved to take advantage of the environmental threat defenses of specific plants. Evolution is a natural process wherein certain traits are selected based on the survivability of offspring. Traits are passed on to offspring based on whether the next generation is able to survive long enough to reproduce.
There is evidence that a spider species, Lyssomanes viridis, commonly known as the Magnolia Green Jumping spider, may have co-evolved with the American Sweetgum tree, Liguidambar styraciflua. This tree produces a wide array of secondary metabolites to deal with environmental threats, most notably the monoterpene terpinen-4-ol. Terpinen-4-ol is also the main constituent of Melaleuca (Tea Tree) and Marjoram essential oils.
The jumping spider prefers to lay its egg sacs on the leaves of the sweetgum tree. In the lab, the spiders choose to cling to leaves of the sweetgum tree when given a choice with leaves from other trees from the area. Hatching success is also considerably improved when the eggs are laid on sweetgum leaves as compared to other leaves and plastic controls.
Fascinatingly, the spider’s egg sacs are specially woven to maximize their exposure to the volatiles coming from the tree. Generally, spider egg sacs are compact and dense. The jumping spider’s egg sacs are sparse with space between each egg, allowing for maximal surface area for the volatiles to land on.
As more research is done, it will be of no surprise if more unique evolutionary relationships like this emerge. Animals certainly have learned unique ways of taking advantage of the power of essential oils. We humans can learn a lot!