Pests in the Garden

I’m on a hunt for a small enough spider to image while it’s alive, so I’ve been hunting in the grass and in my small porch garden for anyone who fits that bill. There’s a surprising amount of wild space in the city, and even in a place like Brooklyn, plenty of creatures make their homes, so I’ve been pleasantly surprised to find webs and crawlies on most of my hunts. I even recently found a chrysalis for a cabbage looper moth on the underside of a basil leaf in my garden (unfortunately it hatched before I had a chance to image it; a missed opportunity, but I can’t begrudge the little creature its good fortune, even if it did eat half my basil). Yet, I’ve had a hard time finding tiny spiders.

I was thrilled, then, when I came out to find that my tomato plants were covered in delicate webs, with many small dots walking among them. Surely, I thought, this was a sign of recent spider hatching. Not so. I was unpleasantly surprised to find that these were not spiders, but spider mites. And that they had been laying eggs.

Spider Mite Glass Slide 2 Spider Mite Egg

The jaws on that little thing are pretty frightening; which makes me glad they’re only used for drinking sap from plants (my tomatoes in this case…which is not great). Imagining the mite under a slide cover seemed to press it down a little more than I wanted, so I took the advice from an earlier post on this site and filmed them on their leaves instead. This both illuminated a lot about their world to me (the relatively mountainous terrain of the tomato leaf to their tiny bodies) and made me realize how bad the infestation was. I had assumed I caught only a couple of mites, but upon looking at them on the leaf, realized I had at least ten on a very small sample size. And again, the eggs.

It also made me realize how social they are, constantly touching and interacting with each other, even if only for the purpose of mating and colony protection. Watching one clean itself as it walked along my slide cover (because of course, they wouldn’t only stay on their leaf; like me, they had to explore), I thought about the overlap of thought and reaction. I know the spider mite does not think (it is questionable whether it even has a nervous system), but here it engages in a behavior I find recognizable as something my cat does.

An attempt at taking a high-mag video revealed a lot more detail of the movement of fluids within it.

Of course, since I was already looking for pests on the tomato plants, this was a good opportunity to hunt around a bit and figure out who has been eating my other plants. The garden is open to the street and confined to pots. For whatever reason, many bugs like to make it their homes (see above about the chrysalis). A little further hunting and I found aphids dwelling on some of my herbs and my tomatoes (what is it with the tomatoes?). I nabbed a tiny reddish insect that I take to be one of the nymphs of the aphids and was happy to have a chance to take some images of it.

Aphid is my best identification of it, though it might also be the nymph of a scentless plant bug (according to Google). Tiny and swift, this little one didn’t want me to look at it. Only by placing it under a slide cover and holding it in place was I able to get a steady glimpse of it. The scope shows me the inner working of its gut, and the mechanics of its moving legs.

Aphid Nymph Thorax 2

It shows me the way it moves, also, when it runs away from my viewer.

Eventually, the aphid found its way back outside (to another plant) and the spider mites…well, I’m still trying to control their colony. It’s late in the season, but I want all the tomatoes I can get.

I’ve observed before that looking at traditionally strange and monstrous creatures up close often has the effect of making me feel like I can more easily relate their existence to my own. Perhaps it is their resemblance to ticks, or perhaps it’s the fact that they’re eating my tomatoes, but that hasn’t happened with the spider mites.

I suppose the lesson here is that the ecosystem doesn’t much care whether I find it beautiful or cute or not. The spider mites on my tomato will live their lives as they want, perfectly evolved for their purpose. And our lives will clash and clash again, so long as my goals of growing fresh vegetables provide opportunity for them to meet their goal of eating sap. So the best I can do, assuming I don’t want to give up my garden, is to care for my plants as best I can and make peace with the fact that my garden is not mine alone, that even that small space can be home and food for caterpillars and aphids and mites and spiders (hopefully), all of whom are just doing the same thing I am in the world. Working for survival in a big city.

It’s also a sign that next spring I need to go hunting for some ladybug larvae and praying mantis eggs. My garden could use some apex predators.

 

9 Comments Add yours

  1. Manu Prakash says:

    @Matt: I just saw the post and the videos. The last movie is incredible – with a tiny little bubble inside the gut. It’s fluctuating like I have never seen anything like that. Absolutely incredible.

    Do you know what that is – it could be a bubble inside a gut undergoing peristaltic motion. Absolutely beautiful.

    Cheers
    Manu

  2. Matt.Rossi says:

    @manu,

    I’ve observed similar bubbles in the guts of other arthropods (if you look at the crab megalops video, you can see one in it, also). I wonder if it’s just some air the insect has sucked into itself or if it’s actually a structure within the gut. Any entomologists in the community who might know?
    M

  3. Manu Prakash says:

    @Matt: I will send the link to a couple of entomologists – @Aaron – where are you?

    cheers
    manu

  4. laksiyer says:

    Exquisite videos. Love the high power view.

  5. Aaron says:

    @manu & @Matt, interesting post! As mentioned, the insect in the images/videos appears to be a true bug nymph rather than an aphid.

    As for the odd bubble, in insect physiology we learned that food is moved down the gut by peristalsis muscular contractions but I haven’t seen a video like this before so I’ll do a little more digging; very neat.

  6. Kate Honan says:

    @Matt Can you give some detail on how you contained/prepared the slide the living insects? You referred to a coverslip on one.

  7. Kate Honan says:

    The videos are amazing!

  8. Matt.Rossi says:

    @Aaron: thanks! I’ll update my notes on the true bug.
    @Kate My usual MO when working with bugs is to try to convince them not to move very much, which usually means pinning them with a slip cover. It doesn’t seem to hurt them, but it restricts their motion enough that they don’t want to go anywhere, which makes videoing them a lot easier. In the second video, I’m filming it with no coverslip, and you can see I’m sort of chasing it around the slide a bit. With plankton, which I’ve shot more often, that’s not usually a huge problem, since plankton tends to drift (except copepods…for such tiny creatures, they can really get around), but bugs move quickly and jerkily.

    I should note that the equipment I took these with is a modification of the foldscope design that puts the lens and viewer on a different piece of cardboard than the slide, which gives me a little more control over the airspace around the slide, so I can use well slides without covers with no problem. It makes maintaining focus tough, though.

  9. Matt.Rossi says:

    @Aaron: a question comes to mind; do bugs pass gas? Is it possible the bubble is bacterial gas?

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