No assassinations today! But an "assassination attempt."
There it was, a leafhopper assassin bug, Zelus renardii, waiting for prey atop a Mexican sunflower, Tithonia rotundifola in a Vacaville pollinator garden. Yes, it's native to North America.
The assassin bugs, family Reduviidae, are ambush predators. When they ambush a predator, they stab it with their rostrum, inject venom, and suck out the juices. Or as UC Berkeley entomologists Jerry Powell and Charles Hogue write in their book, California Insects, "The victims, which include all kinds of insects, are snatched by quick movements of the forelegs, and immediately subdued by a powerful venom injected through the beak."
UC Statewide Integrated Pest Management Program (UC IPM) says that "Assassin bug adults and nymphs (immatures) have an elongate head and body and long legs. The narrow head has rounded, beady eyes and long, hinged, needlelike mouthparts. Adults and nymphs can walk rapidly when disturbed or capturing prey. Adults tend not to fly."
"Assassin bugs can occur on almost any terrestrial plant including row and tree crops and gardens and landscapes. All species are predators of invertebrates or true parasites of vertebrates," UC IPM relates. "Most assassin bugs feed on insects including caterpillars, larvae of leaf beetles and sawflies, and adults and nymphs of other true bugs. Nymphs and adults ambush or stalk prey, impale them with their tubular mouthparts, inject venom, and suck the body contents. Zelus renardii produces a sticky material that helps it adhere to plant surfaces and ensnare prey."
Some 7000 species of assassin bugs reside throughout the world. When they feed on such agricultural pests as fleahoppers, lygus bugs, aphids, caterpillar eggs and larvae, they are considered biological control agents.
However, "assassin bugs are not considered to be important in the biological control of pests, unlike predatory groups such as bigeyed bugs and minute pirate bugs," UC IPM says. "Assassin bugs are general predators and also feed on bees, lacewings, lady beetles, and other beneficial species. Certain species feed on the blood of birds, mammals, or reptiles, including conenose bugs and kissing bugs (Reduviidae: Triatominae)."
The one we saw today?
A long-horned bee, Melissodes agilis, stopped for a sip of nectar, spotted the assassin bug, and buzzed off, leaving only its shadow behind.
A pollinator garden is a study in diversity--and of inclusion and exclusion.
The residents, the immigrants, the fly-bys, the crawlers, the wigglers, the jumpers. The big, bad and bugly. The prey and the predators. The vegetarians and carnivores.
The nectar-rich flowers attract honey bees, bumble bees and butterflies. And right near them are the predators: the praying mantids, dragonflies and assassin bugs.
The assassin bugs, family Reduviidae, are ambush predators. They resemble human assassins (or at least those on the movie screen!): long narrow neck, beady eyes, and sturdy body. When they ambush a predator, they stab it with their rostrum, inject venom, and suck out the juices. Or as UC Berkeley entomologists Jerry Powell and Charles Hogue write in their book, California Insects, "The victims, which include all kinds of insects, are snatched by quick movements of the forelegs, and immediately subdued by a powerful venom injected through the beak."
Such was the case with the assassin bug, Zelus renardii, this week. We watched one lie in wait on a Mexican sunflower (Tithonia); we watched another dine on an unidentifiable prey on a milkweed blossom; and we watched yet another stab a lady beetle (aka lady bug) on a leaf.
Everybody eats in the pollinator garden.
Ever seen assassination attempts in your garden?
They are not pretty if you're the prey. Neither are the successful attempts.
Take the Zelus renardii, aka the leafhopper assassin bug.
They've been hanging out in our nectarine tree, cosmos, passionflower vine and Cleveland sage. They stalk or lie in wait and then jab their prey with their long rostrum, injecting a lethal saliva. Next: they suck out the contents. They "assassinate" such pests as aphids, leafhoppers, and caterpillars of the cabbage white butterfly.
Assassin bugs also feed on beneficial insects, too, such as bees, lacewings and lady beetles, aka ladybugs.
They're often confused with kissing bugs. Can "assassin bugs can carry Chagas disease, which can transmit to humans?" a reader asked.
We asked noted entomologist Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis, for comment and clarification.
"Assassin bugs and kissing bugs belong to the same family of insects, the Reduviidae," Kimsey said. "However, biologically they are very different. Kissing bugs belong to 20 or more species in the subfamily Triatominae. They are nocturnal blood feeders, and you almost never see them during the day. Most of these species in California are infected with the protozoan that causes Chagas disease, but because of differences in how they feed, few if any can actually transmit it to humans."
"The pathogen is transmitted in their droppings and have to be inhaled or scratched into the skin," Kimsey pointed out. "This only happens if the kissing bug defecates during feeding. The California species do not defecate until they leave the host and go back to a resting site, so the chances of getting Chagas disease from a bug in California are cosmically small. The assassin bugs you see during the day belong to an entirely different group of reduviids. They are all predators on other insects. Some of them, like the common garden assassin bug Zelus, are irritable biters but they do not transmit any kind of pathogen to anything."
There I was, walking across the University of California, Davis, campus to the Environmental Sciences Building for an agricultural communicators' meeting: a notebook in my hand, cell phone in my pocket, and my trusty pocket camera strapped around my neck.
Sometimes it's good not to lug around a 10-pound camera. Not this time, however.
Right inside the soybean planter box, I saw it--an assassin bug spearing what looked like a bee.
This was a predator-prey encounter between the assassin, Zelus renardii, and a bee, which native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis and an instructor of The Bee Course, identified as a male metallic sweat bee, Lasioglossum (Dialictus) sp., possibly L. tegulariforme.
I aimed the tiny camera and grabbed a couple of images before the predator, with prey attached, crawled beneath a soybean leaf.
Assassin bug are predators and don't distinguish between beneficial insects and pests. Still, we like them in our garden because they eat a lot of soft-bodied insect pests like aphids and leafhoppers.
Speaking of eating insects...the UC Davis Honey and Pollination Center is sponsoring a "Bugs and Beer" event on Saturday, Nov. 1 in the Robert Mondavi Institute for Wine and Food Science. It promises to be a cricket-kölsch kind of affair.
Beer expert Charlie Bamforth, Anheuser-Busch Endowed Professor of Malting and Brewing Sciences at UC Davis, will lead a joint tasting with celebrity bug chef David George Gordon, author of "The Eat-a-Bug" cookbook.
Bamford, known as "The Pope of Foam," is an icon around campus and the beer-brewing world. He's considered one of the country's most intriguing professors, noted Amina Harris, director of the Honey and Pollination Center. And David George Gordon--a fellow with three first names? He's been featured in the Wall Street Journal, Time magazine, and the National Georgraphic Kids.
Registration opened Monday (http://www.rmi.ucdavis.edu/events). Tickets are $50, general admission, and $25 for students. And, of course, "Bugs and Beer" is open only to those 21 and over because beer will be served.
We don't know what kind of bugs Gordon will serve, but they probably won't be assassin bugs. Bees, maybe. Specifically, maybe that "Three-Bee Salad?" on his website?
It wasn't much of a fight.
The assassin bug scored a TKO.
Here's what happened: an assassin bug ambushed a spotted cucumber beetle in the Häagen-Dazs Honey Bee Haven at the Harry H. Laidlaw Jr. Honey Bee Research Faciility on Bee Biology Road, UC Davis.
It was "good guy vs. bad guy."
It was "beneficial insect vs. major agricultural pest."
The assassin bug (Zelus renardii) is a force to be reckoned with, especially when it comes to a spotted cucumber beetle (Diabrotica undecimpunctata).
The assassin bug wears no white hat but it should. A cunning predator, it lies in wait and stabs an unsuspecting prey with a lethal toxin powerful enough to paralyze and dissolve tissue.
Then it's all over but the feeding.
The assassin bug sort of looks like a cartoon character, with its beady eyes, long beak (proboscis) and its long, slender antennae.
The spotted cucumber beetle looks a little like a ladybug (aka lady beetle) except for its coloration. It's a 12-spotted greenish-yellow insect. And a pest. Diabrotica dines on young, tender plants like cucumbers, squash, pumpkins and melons (cucurbits). It also transmits a virus.
So it was the good guy vs. the bad guy. Zelus vs. Diabrotica.
This time the good guy won.
That loud cheering sound you hear is from all the melon growers out there.