Fear and loathing

Over the past few weeks, Prince George and other parts of British Columbia have seen a massive outbreak of tent caterpillars. And that, of course, means that people have been talking about insects. A lot. In fact almost everyone in town has become, at least for a short while, an amateur entomologist. In some cases, I have heard some pretty interesting observations from people. There have also been a few fascinating forays into applied economic entomology as well – my favorite being the lady who filled her Shop Vac half full of soapy water and used it to suck the caterpillars off of her shrubs.

Of course, an infestation of this size has unpleasant aspects. My wife and kids did not like going out in the backyard during the peak of the outbreak. And I don’t blame them, as I wasn’t too keen on it either. A short walk through our yard would leave us draped in zillions of invisible strands of caterpillar silk with a few of the creatures crawling up our necks. And even a simple task like coiling the garden hose would leave your hands covered in squished caterpillar goo. So, I fully understand not fully appreciating these creatures when they occur in vast numbers. Beyond making parts of our city look like autumn is already here, they have been just a general nuisance.

That said, I do not understand today’s editorial in the local newspaper. The editor spent a lot of column space writing about insects, pulling out some interesting and salient facts. Yes, insect biodiversity is astounding. Yes, some of them would likely survive even if an apocalyptic natural event wiped out all of human life. Yes, as implied, we share a more recent common ancestor with other vertebrates than we do with insects. All valid points.

Then these bits:

“Our hatred of caterpillars and other bugs also has a basis in evolution.”


“We’re right to fear and hate them as much as we do.”


Since the muse for the editorial seems to be the swarms of tent caterpillars in town, let’s start with some reasons not to “fear and hate” them.

First, although they cause a great deal of visible damage, they are unlikely to kill many trees at all. So on the “fear and hate” side of the ledger we are left with temporary cosmetic damage and a bit of hassle in the yard for a few weeks. On the other hand, they do have benefits. This article nicely summarizes many of them. For instance:

  • they are a natural part of a functioning forest ecosystem.
  • their removal of canopy leaves allows light to the forest floor, giving some plants down there a leg (or limb?) up.
  • caterpillars and the moths that they become provide food for other organisms.
  • caterpillar poop gives a burst of nutrients to the forest floor.
  • all of these things, over time and many cycles, make a forest what it is.

In other words, if there weren’t periodic outbreaks of defoliators, our forests would be much different from what we enjoy today both in terms of the forest structure and the plants and animals that live there.

But, even if you don’t believe me that the benefit side of the ledger is much more substantial than the detriment side for tent caterpillars, perhaps you’ll agree with me on some easier-to-prove examples:

If this recent caterpillar outbreak has shown us anything, it is that people are fascinated by insects – and by nature in general.

To give the editor the benefit of the doubt, as pointed out by a colleague of mine:

And perhaps that’s true; perhaps the editor meant “respect.” But, one way or the other, I would prefer more coverage of the wonders of nature and more encouragement for people to get outside and to see what’s really going on out there, than demonization of vast segments of the natural world with careless words – even if the intent of those words is mainly to amuse. If we want people to care about the global environment, it’s not wise to begin with making them think that they have reason to hate the local fauna and flora.

Rather show people why it’s so awesome out there, and they’ll begin to understand why we are all so intimately connected with those very insects that are buzzing around our yards and jogging paths.

And in time that will turn more people from being armchair environmentalists (at best) to being actual hands-in-the-soil and boots-on-the-ground naturalists who have a stake in real conservation.

To spray or not to spray?

Earlier this afternoon I was interviewed by the local television station news program on the occasion of today being Canada’s National Day of the Honey Bee.

As I noted in my previous post, our city is currently being inundated with forest tent caterpillars. They are everywhere, and it’s hard to take a walk in one of our city’s wonderful green spaces without literally bumping into them at every turn as they rappel out of the trees above. Yesterday evening I spent a bit of time in my yard and then spent most of the rest of the evening removing strands of caterpillar silk that had festooned me.

What does this have to do with Honey Bee Day? Well, as the planned news story is bound to point out, the temptation for caterpillar-plagued homeowners is going to be to spray the heck out of the little leaf-munching critters with whatever pesticide they can get their hands on. That urge, I would argue, is a mistake for a number of reasons:

  • At this point in the tent caterpillar infestation, they have done almost as much damage as they can do. I have been observing that they are growing quite well (unfortunately for us!) and are going to be entering their pupal (cocoon) stage shortly. In other words, spraying now won’t do much to reduce any remaining damage that they may still do. The damage is mainly done.
  • In any case, in the face of such a massive infestation, spraying a can of pesticide at a few of the caterpillars is analogous to facing up against the JTF2 with a BB gun. You may inflict some minor damage for a moment, but you’re going to be overrun anyhow.
  • For smaller trees and shrubs (many of which these caterpillars only eat reluctantly at best anyhow), physical removal is as effective as spraying, and definitely much better for the environment.
  • And, spraying WILL impact other arthropods that are beneficial, including enemies of the forest tent caterpillar… and pollinators such as honeybees and various native pollinators (bumblebees and others).

That final point, I believe, is going to be one of the messages of the news item later today. Specifically, don’t lose sight of the forest for the trees.

Or, in other words, don’t lose sight of…

  • the honeybees
  • the native pollinators
  • the spiders that eat garden pests
  • the parasitoid flies that dine on tent caterpillars
  • the ladybugs that eat your aphids
  • the seed-dispersing ants
  • the dragonflies that eat mosquitoes
  • that beautiful swallowtail butterfly that brightens your day
  • …you fill in the blank…

…for the caterpillars.

I realize that even after reading this, some folks are still going to want to buy a can or two of pesticide and use it in their yards. If that is you, then:

  • be sure to carefully follow the directions on the label because they are there for a reason.
  • remember that these are powerful chemicals and that more is not necessarily better.
  • do your best to limit your application to the area in which you deem that it’s needed.
  • protect yourself, your kids, and your pets during and after spraying.

I’ll close with a personal story. The other day I was in a garden store buying a few bedding plants and some soil for our gardens and containers. Near the checkout there was a display of pesticide that is labeled for use against forest tent caterpillar. A customer and a store employee were talking about how best to use the stuff. Being a nosy entomologist I joined the conversation and made my case. Following more discussion between the three of us the customer finally said, “well, I know that this won’t really help with the problem in my yard, but I’m just so grossed out by them that I want to do something.”

I’m not sure if she ended up buying the product or not. But I suspect that a lot of spraying goes on for that very reason – i.e. a general dislike of insects – particularly in vast quantities – combined with a desire to do something… anything.

So, one last plea – please carefully consider your need use a pesticide in this situation. This plague will be over for the year soon enough. If we are lucky, natural enemies and disease will knock the population down this year and we won’t be seeing these creatures in any substantial quantities for quite a few years to come. In the meantime pesticides will not alleviate the problem, but they might end up hurting some friends that you may not even know that you have.

If you would like more information on pollinator conservation, please see this page hosted by the Xerces Society.


(And a small side note: I’ve been seeing a few “friendly flies” around lately. So hopefully their population levels will pick up and they’ll help to wipe out this infestation. Fingers crossed! Keep in mind that these creatures are called “friendly” for a reason. Specifically, they like to land on various surfaces, including people. But they are harmless to everything except for forest tent caterpillar cocoons. If they are going to be a factor in knocking down the tent caterpillar infestation, there are going to be a lot of them around very soon. Here is a picture of one so that you know what to look for. Click on the photograph to enlarge. Notice the stripes on the thorax, the pattern on the abdomen, and the nice, big reddish/burgundy eyes.)

Good news x 3

Most days environmental news is bleak to say the least. Truthfully, much of what’s going on is bleak. Species are going extinct at record rates. Climate change seems to be accelerating. Environmental degradation is having real effects on real people.

But even though the bad news is usually what makes it onto the evening news, there are bits and pieces of good news as well. And those deserve to be highlighted. So, let’s take a look at three of those today.


A clawed cave spider: I always get excited when I hear about new species discoveries. That’s partly because it reminds me that no matter how much we think that we’ve figured out, there are still zillions of cool things out there that we have no clue about. We just need to look – sometimes in difficult places. In this case, the cool new find is a new species of spider, Trogloraptor marchingtoni. And not just a new species, but seemingly an entirely new family. If a new species is a big deal, a new family is an even bigger deal. By way of analogy ostriches, pelicans, and hummingbirds are each in separate bird families. So you might say that this newly discovered spider is approximately as different from other groups of spiders as those three groups of birds are from each other.

Trogloraptor is about 4 cm in diameter and lives mainly in caves and some old growth forests. It has substantial claws on its legs, but it is not clear what they are used for. And, now that we know about this creature there are a ton of other new and interesting things to find out as well. What will those discoveries be? Only time, and more hard work, will tell.

An (un)extinct snail: The Mobile River Basin in the southeastern United States is home to an amazing diversity of freshwater mollusks. Or perhaps it should be said that it was home to an amazing diversity of freshwater mollusks. After years of human influences, several dozen species are now extinct. However, in a recent survey of the snail fauna of the Cahaba River, researchers found a small population of a snail that has been thought to be extinct for decades. The snails can be bred in captivity and the authors of the linked research article point out several locations that may be suitable for reintroductions.

Monarch butterflies finally find protection: I’ll probably devote an entire post to monarch butterflies in the near future because they are so amazing. Briefly, these insects migrate across a huge swath of North America to a few very small wintering areas in forest groves the mountains of Mexico. So, entire populations that cover large chunks of geography in the summer are dependent upon a the survival of a few hectares of trees. Because of this, they are highly susceptible to deforestation in that region. Illegal logging has been impinging on these winter redoubts for decades. Removal of trees, even trees not used by the butterflies for roosting, allows more rain below the canopy. Wet butterflies are highly susceptible to winter cold.

The whole situation has been extremely dire in recent years. But now comes news that cooperative work between government, NGOs, private individuals, and the people who live near to the butterflies’ overwintering groves has almost completely eliminated illegal logging. Residents are now replanting trees in the butterfly groves and are working on developing a more robust ecotourism-based economy.


Yes, there are spots of good news out there as well. It pays to look for them because we need to take the time to highlight these events and accomplishments. They are due in large part to the dedication and efforts of researchers and, as exemplified in the case of the monarchs, to the people who are most likely to be affected by the negative consequences of doing nothing.