Summer temperatures in the Red Cliffs Desert Reserve may often exceed 100 degrees with only a 15 degree drop at night. This is not uncommon in this portion of the Mojave Desert. Over the millennia, amazing adaptations have been made by plants and animal alike to enhance their survival here. Anatomical, physiological and behavioral adaptations are on display every day.
Some are quite obvious like cacti, whose leaves have been reduced to spines. What is not as obvious are the remarkable symbiotic relationships that have evolved to enhance survival in these extreme conditions
A symbiotic relationship is best defined as two organisms living together where one or both benefit from the relationship and neither is harmed.
Anyone who has hiked in the deserts of Utah has encountered rocks splashed with a dazzling display of every color in the rainbow. We call them Lichens, but you may not be aware that they are examples of a mutualistic symbiosis where two organisms live together and both benefits from the relationship. Lichens are actually a partnership between a fungus and a photosynthetic organism, usually an alga or cyanobacterium.
The fungus provides a protective structure and absorbs water and minerals from rain, dew, or dust. They also offer shelter from harsh desert conditions such as intense sunlight and temperature extremes. The alga or cyanobacterium are the source of color as they contain Chlorophyl, Carotenoids, Anthraquinones, Uric acid and Melanin’s. They produce food by photosynthesis, supplying life sustaining energy for both organisms
Another symbiotic relationship known as commensalisms, where one organism is benefited and the other is neither harmed or benefited, can be found associated with Desert Trumpet plants. These tall slender plants have hollow and dynamic inflated stems. The inflated portions of the stems are penetrated by Cynipidae wasps as they lay their eggs inside the hollow cavity where their larvae develop in a protected environment.
The resulting hole left when the larvae emerge as adults, allows access inside the chamber, sometimes for years. a student of mine cataloged over 20 species of insects, spiders and mites that were secondary inhabitants of the hollow stems.
Perhaps the most interesting of all symbiotic relationships found in the desert is the creation of insect galls. Galls are remarkable cancerous like plant growths, produced as a reaction to chemicals injected by insects. This is most commonly initiated by gall wasps, midges, and aphids. Galls come in all shapes, sizes and architectural design and serve as a protective capsule for insects eggs and developing larvae.
Some look like cotton balls others resemble land mines or satellites or simple cupping protuberances on a leaf. These galls provide both food and shelter for the insect’s developing larvae. Despite the harshness of arid landscapes, deserts host a surprising diversity of galls. Each insect species typically induces a highly specific gall on a particular host plant. Chemicals secreted by the insect or its larvae manipulate the plant’s hormonal pathways, redirecting growth to form a unique structure that supports the insect’s life cycle.
I am not averse to stopping and dissecting galls to examine the larva inside. I am occasionally surprised to find secondary inhabitants such as spiders, mites and the like. While insects benefit from the galls protection the host plants generally do not seem to Any significant harm.
I’m professor Marshall Topham and I’m Wild about Utah’s Mojave Desert.
Credits:
Images Courtesy & Copyright Marshall Topham, Photographer
Featured Audio: Courtesy & © Bob Holmes, Composer, Hugh Jones, Producer, Rubber Rodeo-Before I Go Away, 1984, https://www.discogs.com/release/9698183-Rubber-Rodeo-Scenic-Views
Text: Marshall Topham, https://ees.utahtech.edu/faculty-staff/
Additional Reading: Lyle Bingham, https://bridgerlandaudubon.org/
Additional Reading
Wild About Utah pieces by Marshall Topham https://wildaboututah.org/author/marshall-topham/
Cane, Jim & Kervin, Linda, Gall Insects, Wild About Utah, January 13, 2011, https://wildaboututah.org/gall-insects/
“Sagebrush is an important member of an ecosystem that helps support many birds, reptiles, amphibians, and mammals, as well as an abundance of insects and microbes. One study found nearly 300 arthropod species directly living on just a few plants including- 72 spider, 237 insect, 42 of which were gall-forming, amongst many other species.”
Greene, Jack, Sage Steppe, Wild About Utah, June 15, 2015, https://wildaboututah.org/sage-steppe/
“Pests and Potential Problems Some ecotypes of rubber rabbitbrush are infected by stem galls, which are caused by two species of tephritid flies (Aciurina species) (McArthur 1979). There are no reports of negative effects caused by the galls. ”
Rubber Rabbitbrush, NRCS, USDA, https://www.nrcs.usda.gov/plantmaterials/mtpmcpg9696.pdf