Trego's Mountain Ear

Author: EntomologistJed

• Ask The Entomologist

  

  Shiny flies

  Earlier this week we visited Trego School, to see the results of the salmon snagging fieldtrip. After the fish were had been cleaned and packed away for children to take home, I saw many bluebottle and greenbottle flies, as well as a few paper wasps, flying about outside of the school, sucking up fish juices.

  Bluebottle and greenbottle flies are blowflies, members of family Calliphoridae, a name which translates to “carriers of beauty”. Rather fitting, given their bright metallic hues. Additionally, adult blowflies are excellent pollinators, and a very good thing to have in your garden.

  

  Blowflies have an incredible sense of smell. In most parts of the world, blowflies find bodies within minutes of death, detecting the first smells of decay long before humans are able to. When they find the right sort of decay (some blowflies prefer dung to death), blowflies quickly mate and lay eggs before flying off.

  People throughout ancient Greece and Egypt believed that these shiny flies were the souls of the dead. Even today, some people in those countries consider it bad luck to swat at them, for fear that you might kill someone’s ancestor. I think this is a particularly beautiful story.

  Imagine, sitting gathered with family and friends as a loved one passes on, breathes their last breath. Within minutes, you can see their soul, in the form of a beautiful fly, flying about their mouth, nose, and eyes. Almost as if the soul is sorry to leave the body, as if the person wants to stay with their family. Perhaps they say “goodbye” before flying off to the afterlife.

  Today blowflies are appreciated for more than their attractive colors and spiritual significance. They are the most useful insects in forensic investigations – their young are very useful for figuring out time (and sometimes place) of death. While other insects can be used, blowflies are a forensic detective’s best friend.

  

  Blowfly maggots have even been used in medicine, as a way to clean dead flesh out of wounds, preventing sepsis and gangrene. Medical maggot use predates antibiotics! Napoleon’s surgeons noticed that fly maggots increased soldier survival! In the American Civil War, both sides used blowfly maggots to clean deep wounds. Maggots continued to serve and save lives in World Wars I & II, and are used for some conditions even today.

  September 22, 2020
• Ask The Entomologist

  

  Pine Bark Beetles and Fire Risk

  The dense smoke currently hanging over our part of the country has had me thinking about beetles. Why beetles, you say? Pine bark beetles and relatives (genus Dendroctonus) are notorious for killing large stands of coniferous trees (Fir, Larch, Pine, etc.) – even their scientific name translates to “tree killer”.

  As time goes by and environmental stressors increase, we’re seeing more and more tree die-offs related to these bark beetles. Death by bark beetle can triple the rate at which trees go up in flames. It’s not fair to put all the blame on the beetles, though – tree death is ultimately caused by infection from the fungi that the beetles spread. The one bright side of how destructive these beetles and fungi are is that they have been well studied. As a result, there are many ways of controlling their infestations.

  

  The most effective way we can control pine bark beetles on our own is by good management of our forest resources. Keep tree stands resistant to pine bark beetles by thinning trees to a healthy density – beetles are most likely to become a problem in over-crowded woods. Beetle damage will become evident by “boring dust” – spots of reddish sawdusty powder along the trunk, and “pitch tubes” – globs of resin the tree has pushed out, trying to stop a beetle’s tunneling (red pitch tubes likely indicate infestation, while yellow ones often indicate successful defense).

  Remove stressed, fire-damaged, and wind-thrown trees. Promptly clean up fallen timber. Damaged and downed trees are excellent places for pine bark beetles to reproduce, and should be removed before new beetles emerge! Where one beetle feeds and reproduces, there will soon be more – pine bark beetles attract each other to damaged trees by releasing aggregation pheromones.

  

  My favorite method of control involves removing the pine bark beetles’ symbiotic fungi. Without these fungi, most of the beetles can’t reproduce well. Because it’s not practical to directly remove fungi from beetles in the wild, scientists have raised pine bark beetles in captivity. These captive-raised beetles can be inoculated with special aggressive fungi which can outcompete and kill the fungi that wild pine bark beetles carry. The thought is that captive beetles could be released and will interact with wild beetles, spreading their different fungi like a disease. The new fungus will prevent beetle reproduction and thus stop small infestations from becoming large and economically devastating ones.

  Unfortunately, beetle-delivered fungal control treatments aren’t ready for public use yet – ask your Forest Service folks what beetle controls they are researching and testing! If you’re particularly concerned about pine bark beetle infestation, they may be able to use chemical measures like anti-aggregation MCH pheromone to lessen the risk.

  Have you been seeing signs of pine bark beetle damage near your home?

  September 15, 2020
• Ask The Entomologist Community

  

  Ask The Entomologist: Fluffy caterpillars

  Last week I received an “Ask The Entomologist” identification request.
  What is this fluffy caterpillar? It was found feeding on blackberry bush leaves.

  

  First off, adorable. This is a Tussock Moth caterpillar, so called after the little clumps of hair on their backs. Many fluffy caterpillars are in this group, family Lymantriidae. This particular species is called the Spotted Tussock Moth, and is native to our region. It’s not a picky eater, and will gladly eat willow, birch, and a range of other deciduous trees. We have another related species in the area, the Douglas Fir Tussock Moth, which can become an awful lumber pest, and has been linked with some health conditions in forestry workers.

  Beware! While Tussock Moths’ long hairs can feel soft if you stroke them gently, they often conceal shorter special defensive hairs! These “urticating” (itchy) hairs are like tiny spears and can be quite painful – some even come with venom. Many types of Tussock Moth urticating hairs can cause allergic reactions, the Spotted Tussock Moth (the one above) has even caused one case of anaphylactic shock. Even if you’re not allergic to the caterpillars, there’s the possibility of bacterial infection if the hairs break off beneath your skin.

  Tussock moth caterpillars can prove even more dangerous if eaten! Whether by livestock (abortions in mares, presumably others as well), pets (tongue rot documented in dogs), or unattended toddlers (often surgery, no deaths reported yet…) . The most serious condition resulting is that the eaten caterpillars’ hairs can puncture the digestive tract. This may cause bacteria to seep from the intestines into the body cavity, and can cause serious illness. While a healthy organism may be able to survive this, it often proves fatal to unborn young, which don’t have sufficiently developed immune systems.

  These caterpillars can be perfectly safe, and kids can have a great time watching them grow up into pretty little moths, but do be careful! If you think you, your kids, or your pets have been injured by contact with a caterpillar, Mayo Clinic has some medical advice. If you want to kill your Tussock Moth caterpillars, I suggest rubber gloves and a jar of soapy water.

  Looking forward to more bug questions,
  
  EntomologistJed

  September 8, 2020
• Ask The Entomologist

  

  Paper Wasp Body Language

  If you know what signs to look for when you meet a wasp, it’s easy to avoid being stung.

  Have you ever been buzzed by a bee or a paper wasp? They dive bomb you, fly close to your face, even collide with you, but without stinging? Those were probably sentries for a nest, trying to keep danger away. Sentry wasps can be stationed 10 to 20 feet away from the nest they’re guarding, and circle back to it from time to time. These wasps are the ones you’re most likely to come into conflict with.

  Yesterday, I went out looking for some pleasantly aggressive sentry wasps I had met earlier in the week. No luck – the day was too blustery, and all the sentries were huddled alongside the nest. Cold weather is a good time to pull down wasp nests, if you need to do so: fewer active defenders.

  At the nest itself, you’re more likely to see a different set of behaviors than the sentry flight routine. If the wasps in the nest consider you a threat, they will turn to face you, will lower the front of their bodies, and may open their jaws at you. If there are many wasps present, they may pulse their abdomens in unison, indicating that they may sting if provoked.

  

  Beyond this, certain individual wasps are more aggressive than others. In the European Paper Wasp (the primary wasp discussed last week), as well as many related species, there’s a wide range of face patterning even among close relatives.

  

  European Paper Wasps with spottier faces are more likely to be aggressive than those with more uniformly pale faces. Generally, wasps with less dominant faces stay out of the way of wasps with more dominant face patterns. This seems to hold true for wasp-human interactions as well as wasp-wasp interactions. In the below picture, the European Paper Wasp with a spotted face pulsed its abdomen at me (a threat of stinging) while the pale-faced wasp did not.

  Wasps- Not Always Out to Get Us

  wasp Control

  September 8, 2020
• Ask The Entomologist

  

  Wasp control

  I’d wanted to talk about how to read wasp body language this week, but that’ll be postponed. I couldn’t persuade any individuals to do threat displays this week – all live wasps were well-mannered, despite extreme invasion of their personal space.

  Most of the wasps I’ve seen around Trego are Polistes paper wasps. We have two main species here – the invasive European Paper Wasp (Polistes dominula) and the native Golden Paper Wasp (Polistes aurifer). In our area, Golden Paper Wasps peak in July, while the European Paper Wasps peak in August. While both are still around, I’ve been seeing far more European Paper Wasps lately.

  The European Paper Wasp is rather special, in that it doesn’t mind reusing old nests from last year and making them bigger. Because of this, they often reach a larger colony size faster than their native wasp competitors can. As such, these are likely to be most of the problem paper wasp nests you come across.

  The best bait for trapping wasps will vary by season. My neighbors have been having great success baiting their wasp traps with scallop and chicken… this means that the wasps that they are catching are from nests with many developing wasps!

  

  At this, another friend present asked me why folks these days trapped wasps with meat – he remembered his grandmother having lots of success baiting wasps with beer. The answer is that it depends on the season, and what part of their life cycle the wasps are in…

  Early on, a wasp nest is focused on growing: laying eggs and raising larvae to adulthood. Little humans need healthy food, protein to turn into muscle tissue. The same is true of young insects: adult wasps prefer to feed their larvae with protein-rich foods (any meat – caterpillars or dead deer, it makes no difference). If you’re seeing wasp nests with lots of brood cells by your home, consider putting a bit of meat, especially spoiling meat, in your wasp trap!

  

  Adult insects, however, aren’t going to build any more muscle than they already have. We mammals can continue to develop our musculature throughout adulthood. Insects only get bigger by molting, and almost all adult insects do not molt.

  Though they don’t grow, most adult insects do spend a lot of time flying. Flying is very energetically expensive (it’s why hummingbirds are such sugar junkies). Likewise, adult wasps prefer to eat high energy, sugary foods. If you’re trying to trap wasps later in the season, when they’re reproducing less, you’ll have better success baiting them in with sugar solutions, juice, or alcohol.

  Here’s good instructions for making a wasp trap – bait it however you’d like.
  As always, be aware of your local wildlife when setting up insect traps! If you’ve got a bear in the vicinity, it’s probably best to hold off on trapping for a while. They’re at least as fond of meat and booze as the wasps are…

  Next week: Wasp body language: how to tell if they’re aggressive.
  (for real this time – none were aggressive towards me this week, so no useful photos).

  Last Week: Wasps, not always hostile.

  September 1, 2020
• Ask The Entomologist

  

  Wasps… they’re not always out to get us.

  What says midsummer better than unexpected wasp nests? Buzzing uncomfortably overhead, nests full to bursting with developing young. Dreadful things, right?

  What would you say if I told you that aggressive wasps (think of your stereotypical Bald Faced Hornets) aren’t the only kind out there? Even within a single species, there are a wide variety of levels of aggression.

  If a wasp is going to be aggressive to protect her nest, full of her offspring and her sisters’ offspring, she really has to go all out. If a wasp doesn’t give her all when driving potential threats away, chances are that the nest will have to repel more attacks, and the nest will be more likely to be detected by more dangerous predators! Predators who will attack and destroy that nest, despite angry wasps and stings. Both mammalian predators (bears, humans, etc.) and insect predators (especially ants!) are more likely to attack nests that reveal themselves by being aggressive.

  While bears are stereotyped as being very fond of bees’ honey, they also relish eating the “brood”. “Brood” are the developing larvae or pupae that will grow up to become wasps or bees. While you can only get honey from some sorts of bees… you can get delicious brood from any active bee or wasp nest!
  Think of snacking on sugary fresh fruit… now think of eating a ham sandwich… Which one makes you feel more full? Bears, especially young ones, love protein-rich young insects.

  There’s another strategy for survival. What if the wasp was sneaky, stealthy, and conflict-avoidant instead of being crazy aggressive? It turns out that this is a valid strategy for survival, too. Think about it – if nobody knows the wasps are there, nobody will be trying to eat their brood!

  Different colonies of the same species of wasps often vary widely in how aggressive they are! Not all paper wasp nests are terrible… I’ve certainly met some aggressive ones when cleaning roof gutters and peeling off siding, but I’ve met others of the same species who wanted nothing more than to escape notice! Look at this nest, tucked below the hinge of our vehicle’s front passenger door:

  

  These wasps had no interest in attacking us – I got within 3 inches of them with my camera, and none made threat displays. I only noticed them because I saw the same species of wasp flying outside of the vehicle as we started it up… I saw these wasps several times in a row, despite it being parked at different places… including some where this particular paper wasp isn’t common. The wasps were being sneaky – they’d found a warm place to rear their young, inside a protected shell that ants and bears alike would be unlikely to spot them in. And it worked out well for them… until I saw them and decided that I didn’t want them meeting the dog.

  Next week: How to read a wasp’s body language. Apologies, folks, wasp control instead.

  Last week: Control of Earwigs

  Next week: Wasp Control

  August 25, 2020