Hi, I’m Holly Strand from the Quinney College of Natural Resources at Utah State University.
It’s almost Halloween so I’d like to tell you about an unusual creature that has given many people a fright. It has a shiny oversized body with long spiny appendages. Dark eyes stare disturbingly from a smooth, bald head. It eats both living and dead matter. And sometimes it engages in cannibalism.
Katydid Courtesy Stokes Nature Center Scott Biggs, Photographer
Monarch Butterfly Courtesy Utah Division of Wildlife Resources J. Kirk Gardner, Photographer Licensed Under CCL 3.0
Tiger Swallowtail Butterfly Courtesy Utah Division of Wildlife Resources J. Kirk Gardner, Photographer Licensed Under CCL 3.0
Insects are the most diverse class of organisms on earth, with more than 900 thousand known species. With that many different kinds of bugs, it’s no wonder that they take on such a vast array of shapes, sizes, and colors. From Luna moths to fruit flies to millipedes, the diversity of this class of life is immense. Some insects have developed a shape and coloring so deliberate that it’s almost astounding. These insects are mimics – bred to look like something they aren’t, in an attempt to get a leg up on the survival game.
Insects can mimic all kind of things – stick bugs, for example, make such convincing twigs that you’ll never know they’re around until they move. Katydids look just like bright green leaves, and there are some species of caterpillar that in their youngest stages look just like splatters of bird droppings. But the mimics that I find most interesting are those who mimic other insects.
There are two main types of insect-to-insect mimicry. Batesian mimicry occurs when one harmless species mimics another dangerous one. Species that look like something fierce can capitalize on that insect’s dangerous reputation and potentially be safer from predators because of it. A common Utah pest, the peach tree borer, is a moth that very closely resembles a wasp in both its morphology and behavior. Harmless, nectar-eating hoverflies exhibit the black and yellow body stripes of a bee. Apparently, it’s not just humans who want to stay away from the business end of a wasp or a bee – many insect predators, too, give them a wide berth.
Ants also have a fierce reputation in the animal world, and so attract a lot of mimics. A number of spider species not only mimic ants in morphology and behavior, but some also give off ant pheromones, making them smell like friend rather than foe. While many ant-mimicking spiders go undercover as a way to hide from their own predators, some do use their disguise as a way to access the nest of their prey.
Batesian mimicry is a delicate balance. Predators need to catch a wasp or two before they associate that color pattern with dangerous prey. If there are too many tasty mimics around, the predators will stop associating black and yellow stripes with a dangerous object and the mimic’s ploy would fail to work.
A slight variation on Batesian mimicry are insects with false faces and false eyes. Tiger swallowtails – those large yellow and black butterflies – have red and blue spots on each of their hind wings at a place farthest from their body. These spots, combined with the skinny black ‘tails’ from which the species gets its common name, are meant to look like the eyes and antennae of another, possibly larger and more fierce, insect. This imagery is meant to frighten off predators, but also in the case of an attack, to spare the most important part of the butterfly’s body.
The second, less common, form of insect-to-insect mimicry is called Müllerian mimicry. This occurs when two equally distasteful insects come to resemble one another. Most of us are familiar with the monarch butterfly. As caterpillars, they feed exclusively on toxic milkweed. The caterpillars take the toxins into their bodies and retain them as adults, making them not only bad-tasting but also poisonous. Predators have learned to associate that distinct orange and black wing pattern with a bad experience, and therefore leave them alone. Viceroy butterflies look incredibly similar to monarchs – the only difference being an extra line of black on the hindwings of a viceroy. While once thought to be Batesian mimics, recent studies have shown that viceroys are equally unpalatable. Their similarity in looks to monarchs, then, serves to reinforce the distasteful nature of both species.
Mimicry is of course, not restricted to the insect kingdom. Some plants have gotten into the mimicry business in order to trick insects. The hammer orchid, which grows in Australia, has a flower that mimics a female bee. Male bees, in mistakenly trying to mate with the flower, collect pollen that they then carry with them to the next, ensuring pollination of this sneaky plant. So this ingenious tactic some insects use to gain a leg up in the game of survival can also be used against them to the advantage of others. Isn’t life amazing…
For more information and photos of some insect mimics, visit our website at www.wildaboututah.org. For the Stokes Nature Center and Wild About Utah, this is Andrea Liberatore.
Many thanks to Don Viers for his input on this piece.
Credits:
Photos: Courtesy and copyright as marked
Text: Andrea Liberatore, Stokes Nature Center
Additional Reading:
Imes, Rick (1997) Incredible Bugs: The Ultimate Guide to the World of Insects. Barnes & Noble Books. New York, NY
Pyle, Robert Michael (1981) National Audubon Society: Field Guide to Butterflies, North America. Alfred A. Knopf. New York, NY
Viers, Don (2013) Personal conversations
Ritland, David B., Brower, Lincoln P. (1991) The Viceroy butterfly is not a Batesian mimic. Nature, vol. 350, 497-8. Available online at: https://www.nature.com/nature/journal/v350/n6318/abs/350497a0.html
Cushing, Paula E. (2012) Spider-ant associations: An Updated Review of Myrmecomorphy, Myrmecophily, and Myrmecophagy in Spiders. Psyche, vol. 2012. Available online at: https://www.hindawi.com/journals/psyche/2012/151989/
Crepitating Cicada Platypedia putnami Elko Co., Nevada June 2008 Courtesy & Copyright 2008 Jim Cane, Photographer
Cast Nymphal Skin of the Crepitating Cicada Platypedia putnami Elko Co., Nevada June 2008 Courtesy & Copyright 2008 Jim Cane, Photographer
Audiospectrograph of the Crepitating Cicada Platypedia putnami Made with Raven Software Elko Co., Nevada June 2008 Courtesy Jim Cane, creator
East Coast news reports have been abuzz about this summer’s synchronized emergence of the periodic cicada, last seen in 1996 when their parental generation flew. The incessant loud buzzing of these 17 year cicadas has been the dominant sound of mid-Atlantic forests and towns for some weeks now.
The Great Basin also has cicadas. Our two species from the genus Platypedia produce a more subdued mating call. They use crepitation, from the Latin for a crackling sound. Our crepitating cicadas have received scant research attention; even their means of sound production remains uncertain. Their call consists of a trill of accelerating clicks.
You can see an audio spectrograph of their clicking call on our Wild About Utah website. The wings of crepitating cicadas visibly clap to the tempo, leading some to believe that the sound is that of slapping wings. More likely, the snapping sound is generated by the bending of a wing vein or other semi-rigid surface in the manner of a metal dog training clicker. Listen to the similarity.
As with cicadas everywhere, our crepitating cicadas spend years underground as slow growing, wingless immatures called nymphs. Cicada nymphs feed in a manner similar to their smaller kin the aphids, white flies and scales, piercing the roots of trees and shrubs to suck their sweet sap. When and where adult cicadas are abundant, you can see scattered cast brittle skins from which the adults emerged. Tunneling by cicada nymphs has been shown to alter the morphology of Great Basin soils, but it is their collective daytime clicking that grabs your attention.
En masse, they sound like an orchestra of castanets. At sunset, as if on cue, they all become quiet for the night. After hearing our crepitating cicadas clicking all day long, that evening silence is profound.
Credits:
Images: Courtesy & Copyright 2008 Jim Cane, Photographer Recording: Courtesy & Copyright Jim Cane
recorded with Raven software: Bioacoustics Research Program. (2011). Raven Pro: Interactive Sound Analysis Software (Version 1.4) [Computer software]. Ithaca, NY: The Cornell Lab of Ornithology. Available from https://www.birds.cornell.edu/raven.
Sound clip of the call of the 17-year periodic cicada, Courtesy Dan Mozgai, from his website, https://www.cicadamania.com/. Copyright Dan Mozgai.
Clicking sound of the crepitating cicada, Platypedia putnami. Logan Utah, June 2013. Copyright Jim Cane Text: Jim Cane, https://bridgerlandaudubon.org/
Hi, this is Mark Larese-Casanova from the Utah Master Naturalist Program at Utah State University Extension.
As we officially enter summer, it’s easy to notice nature at its peak. Wildflowers are in bloom, birds are feeding their young, and insects fill the air. Life is especially robust near our wetlands, lakes, and streams.
Our aquatic, or wet, ecosystems provide habitat to abundant plants and animals. Only 1% of Utah is wet, but over 80% of all wildlife in Utah depend on aquatic ecosystems for at least part of their life cycle. However, the quality of Utah’s aquatic habitats is often affected by chemical pollution or excessive nutrients and sediment.
Some organisms, including many aquatic insects, only live in the healthiest of aquatic habitats. Many of the insects we see in summer live in the water when young, during the larval or nymph stage, before becoming adults. Three insects in particular- mayflies, stoneflies, and caddisflies- require especially clean, cold streams low in nutrients and high in dissolved oxygen to survive.
Mayflies are aquatic as nymphs and emerge from the water to live as adults for just a day. The external feather-like gills of the nymphs can be seen fluttering along the sides of their abdomen. They feed by scraping algae from rocks.
Stonefly nymphs are well adapted to living among the rocks of swift-moving streams. Their hooked legs grasp the slick rocks as they shred apart plant litter that falls into the stream.
Caddisfly larvae spin a sort of spider silk to glue rocks or sticks together to form a case in which they live. They will also build webs underwater to collect small particles of food that drift by.
The quality of a stream habitat can be assessed by counting the number of different species, or types, of mayflies, stoneflies, and caddisflies. A greater number of species generally means that habitat and water quality are higher. Dramatic decreases in insect diversity from season to season or year to year can signal a decline in stream health. Monitoring aquatic insects over time gives us an accurate picture of the long-term health of our stream ecosystems.
For more information about monitoring water quality and aquatic insects, visit Utah State University Water Quality Extension’s website. Once there, you’ll find a wealth of information about monitoring Utah’s aquatic ecosystems, including Utah Water Watch, a statewide volunteer citizen science program.
