The staff at Moonshine Ink never knows what kind of responses it will receive in its Do Tell! column, and in last month’s replies to “What is your most memorable wildlife experience?” one answer greatly piqued everyone’s interest. Jeff Stoike from Tahoe City recalled a strange encounter with a highly unsightly bug swimming in Lake Tahoe.
As described to me on the phone, Stoike said of his experience: “The bug looked like it could have been five inches long!” and then he detailed how it first attached itself to his daughter’s wakeboard, then to her jacket, and lastly to the wakeboard handle. At one point, the bug, which seemed like it should be crawling on land like a beetle, was actually swimming in the water! After Stoike caught it, he squashed it — because, you know, bugs can be creepy: “It was a responsive reaction,” he said. “What was most amazing was its blood; it was bright green!”
So, an alien insect has entered the waters of Tahoe? According to some sightings, that’s what it sounds like.
Water bugs, aka toe-biters, commonly two inches long but sometimes as big as four-and-a-half, crawl (and apparently swim) in slowly moving streams, creek bottoms, ponds, and lakes in search of food: other insects, tadpoles, sometimes even small fish. Will Richardson, Co-Founder and Executive Director of the Tahoe Institute for Natural Science (TINS), has observed these water bugs in Sagehen Creek, Taylor Creek, and the pond along Bliss Creek near Whale Beach (between Sand Harbor and Spooner). “They’re probably in a lot of areas around Tahoe. I see them mainly in shallow water,” he said.
While they are mostly considered aquatic, the toe-biter does need to surface to breathe, but strangely enough not through its mouth. Instead, the animal raises its backside slightly above water, then sucks in air through its “air straps,” which act like rear-end snorkels. The bug’s unique anatomy also provides a small space under its wings that holds air in the form of a bubble-like scuba tank. While underwater, the bubble slowly diffuses air into the body to help oxygenate.
“They fly too,” said Pete Oboyski, Executive Director of the Essig Museum of Entomology in Berkeley. “It’s how they disperse and probably how the toe-biter got to Tahoe. Our data shows they have been identified in Sierra County in the Sattley area.” Richardson added that their attraction to lights at night, street lights and lights near water, makes them easier to see and to identify.
The toe-biter happens to be the largest aquatic insect in the order Hemiptera, commonly called “true bugs.” What makes an insect a bug is simply a straw-like mouthpiece that pierces its prey in order to suck out bodily juices. “While all bugs are insects, not all insects are bugs,” Oboyski explained.
As shown by a KQED Deep Look Series episode entitled “Don’t Go Chasing Water Bugs,” one of the most interesting facts of this ‘true bug’ is the male’s role in its evolution. It begins with a lot of bouncing; the male rising up and down as if engaged in pushups as it tries to attract females. If a female is sufficiently lured by his erotic action, they mate and she lays her freshly fertilized eggs on his back — as if filling up a backpack, which he then totes around for a couple of weeks. During that time, the male oxygenates the eggs by frequently swimming up to the surface and then back down to the water’s floor, with the eggs on his back looking like rows of pearl-colored ticks or rounded rice kernels.
Once they are hatched, the nymphs detach from the father’s back and swim away to grow into adulthood.
Another source tells of the toe-biters’ role in “regulating the population of other aquatic insects and small vertebrates, making them important components of freshwater food webs” (roundglass sustain, Femi Ezhuthupallickal Benny). This article goes on to add that in several cultures of Southeast Asia these bugs are a culinary delicacy, cooked in soups along with other aquatic insects.
What is not so savored is the bug’s bite (thus its name). Its hook-like claws deftly grasp prey while its rostrum — the long needle-like part in its mouth that makes it a “true bug” — injects venom to paralyze its prey as digestive enzymes break down the insides for consumption. Oboyski conceptualizes the rostrum this way: “[It] pierces its pray and then, as if with a short straw, sucks up the liquefied material of the prey’s body as if it were a smoothy.”
While a bite is lethal to the toe-biter’s prey, it’s not fatal to humans, which is good to know. But still, the thought of that bite! Richardson eased my trepidation, though, by clarifying, “It tends to bite if disturbed, so if you leave it alone it won’t bother you.”
Bites aside, there is a softer note to this seemingly chilling bug, which involves the renowned naturalist and illustrator John Muir Laws. While Laws was enrolled in the Conservation and Resource Studies program at the University of California, Berkeley, he collected insects to study in an Aquatic Entomology course. Unlike the other students, however, and because Laws was averse to killing living organisms and pinning them to a board for observation, the professor granted him permission to study them alive. When it came time to release his little toe-biter friend (in the Belostomatidae family) back into the wild, he called on his mother whom he had lost touch with. In the middle of winter in her warm winter jacket and warm winter boots and with her son by her side, they took a little road trip up to the Sierra to release the toe-biter into a mountain stream. “It was because of that trip and the uninterrupted time we had together,” Laws said, “that I found my mom again.” Whenever his mother would want a moment to reconnect with Laws, she’d say to him, “We need some Belostomatic time.”
But back to the bright green blood Stoike referred to? Oboyski explained it this way: “Insects do not have veins and blood like we do that contains hemoglobin (which carries oxygen and makes our blood red). Instead, they have hemolymph, which has a similar function to blood but a different composition. I am not sure where the bright green comes from, but the color of insect hemolymph varies from group to group.”
