Kissing bugs, triatoma protracta, are parasites of pack rats, living in their nests, and feeding on their blood, while the rat sleeps. Eggs are laid within the nest, and the kissing bug nymphs will also feed rat blood. Sooner or later, the pack rat will die, by predation most likely, and the dependent kissing bugs will not have anything to eat. Starvation forces them to leave the nest and seek a new host; this activity is most common at dusk, after prolonged hot spells. Being strong fliers, they are attracted to lights, but do not flutter around lights, like moths; they will land and walk the remaining distance. If a kissing bug enters your home, remember, it is there for food, and you are the target.
Kissing bugs appear to be attracted to heat and odor. People report finding them in their beds, basically waiting. It is customary for people that have a lot of kissing bugs, to take the sheets off, and check their beds before going to bed.
The name ‘kissing bug’ comes from reports, back in gold rush days, of people being bitten around the lips. This author has not seen that, and most reports of bites are on other body parts. This author was once bitten by one, on the foot. I never felt the bite, but the bite was prominent, and I’d categorize it as a nasty bite, large and really annoying. I tore the place apart looking for it and never found the bug, until…. it came back to get a second feeding a week or so later.
Below are images of adults and nymphs.
Specimens below collected by Paul Cooper, Jason Price, Heather Nordstrom.
Click on an image to enlarge it.
Kissing bug nymphs
Specimens collected by Paul Cooper.
The ruler markings in the following picture are millimeters. These are small galls.
Although Prionus and Ergates are both large beetles that look very similar, you can tell them apart by examining the spines located behind the head, on the forward part of the thorax.
Prionus has three spines on each side of the pronotum, while Ergates has numerous small spines. Please see the photos.
Female California Prionus beetles. Photo by Alice Anderson
Closeup of spines on prothorax of California Prionus:
Close-up of head of the right side above female:
The Common Eumenid Wasp
When oak trees first leaf out, their leaves are vulnerable to attack by oak worms, the most common being the oak groundling, Telphusa sedulitella and here. These small moths emerge as adults just as the oak leaves open. These new leaves do not have protective chemicals in them yet, as the tree needs time to synthesize and accumulate sufficient toxins to defend their foliage.
The small green worms start eating the oak leaves. There is a race on now, as the caterpillars eat and grow, and the oak leaves synthesize their defensive chemicals. The time period between bud opening and defensive chemical buildup is all the time the oak worms really have to grow and pupate. Once the leaves have accumulated their toxins, the oak worms can no longer easily attack the trees.
It is in this time interval, between leaf bud opening and the leaves building up their defense, that we see the primary predator of oak worms, the eumenid wasps. Although they resemble yellow jackets, eumenids are not social insects; that is, there is no queen and no colony, and as such, they are not aggressive.
Eumenid wasps are beneficial, hunting oak worms and reducing defoliation. The wasp females search oak leaves for the caterpillars, paralyze them, and then carry them to their nests, where the paralyzed worms serve as food for the developing wasp larvae.
Here is where most people encounter eumenid wasps, as the wasps often nest in crevices under the eaves of houses. The male wasps tend to hover near nesting sites, waiting for females to return, and the opportunity to mate. This behavior can make people think there is a serious problem, because they see a lot of wasps and assume they present a risk.
But don’t worry. The wasps are policing your trees, removing defoliating insects, maintaining the health and vigor of your oaks, and are not aggressive in nest defense. In the Bay Area, oak worms actually do defoliate oaks. Thanks in part to the actions of eumenid wasps, this does not occur in the foothills.
The wasps disappear when the oakworms pupate, usually by the first or second week of June.
The best taxonomy work on these wasps is probably “A character analysis of the North American potter wasps (Hymenoptera: Vespidae; Eumeninae)” by James M. Carpenter and Jeffrey M. Cumming.
IMAGES: click on an image to enlarge it.
Here are abdomens of three individual eumenid wasps, to allow comparison of the abdominal striping patterns.
Eumenid wasp stinger details:
Details of thorax:
Details of face: