This post was partly inspired by, and shares some themes with, this Joe Carlsmith post. My post (unsurprisingly) expresses fewer concepts with less clarity and resonance, but is hopefully of some value regardless.

Content warning: description of animal death.

I live in a small, one-bedroom flat in central London. Sometime in the summer of 2023, I started noticing moths around my flat.

I didn’t pay much attention to it, since they seemed pretty harmless: they obviously weren’t food moths, since they were localised in my bedroom, and they didn’t seem to be chewing holes in any of my clothes — months went by and no holes appeared. [1] The larvae only seemed to be in my carpet.

Eventually, their numbers started increasing, so I decided to do something about it.

I Googled humane and nonlethal ways to deal with moth infestations, but found nothing. There were lots of sources of nontoxic methods of dealing with moths — like putting out pheromone-laced glue traps, or baking them alive by heating up the air — but nothing that avoided killing them in the first place.

Most moth repellents also contained insecticide. I found one repellent which claimed to be non-lethal, and then set about on a mission:

  1. One by one, I captured the adult moths in a large tupperware box, and transported them outside my flat.
    1. This was pretty hard to do, because they were both highly mobile and highly fragile.
    2. They were also really adept at finding tiny cracks to crawl into and hide from me.
    3. I tried to avoid killing or harming them during capture, but it was hard, and I probably killed 5% or so of them in the process.
  2. Then, I found the area where I thought they were mostly laying their eggs, and sprayed the nonlethal moth repellent that I found.

I knew that if this method was successful, it’d be highly laborious and take a long time. But I figured that so long as I caught every adult I saw, their population would steadily decline, until eventually they fell below the minimum viable population.

Also, some part of me knew that the moths were very unlikely to survive outside my flat, having adapted for indoor living and being not very weather resistant — but I mentally shrank away from this fact. As long as I wasn’t killing them, I was good, right?

After some time, it became clear this method wasn’t working.

Also, I was at my wit’s end with the amount of time I was spending transporting moths. It was just too much.

So, I decided to look into methods of killing them.

I was looking for methods that:

  • Were very effective in one application.
    • After all, if I could kill them all at once, then I could avoid more laying eggs/hatching in the meantime, and minimise total deaths.
  • Had a known mechanism of action, that was relatively quick & less suffering-intense.

I called a number of pest control organisations. No, they said, they didn’t know what kind of insecticide they used — it’s…insecticide that kills moths (but it’s nontoxic to humans, we promise!).

So, I gave up on the idea of a known mechanism of action, and merely looked for efficacy.

The pest control professionals I booked told me that, in order for their efficacy-guarantee to be valid, I needed to wash every item of clothing and soft furnishings that I owned, at 60℃.

For a small person with a small washing machine, a lot of soft furnishings, and no car to take them to a laundrette… this was a really daunting task.

And so — regrettably — I procrastinated.

September became December, and then the moth population significantly decreased on its own. I was delighted — I thought that if the trend continued, I’d be spared the stress and moral compromise of killing them.

But December became February, and the moths were back, in higher numbers than ever before.

It was hard to walk around on one side of my bedroom without being in danger of crushing them.

I developed new routines to avoid moth deaths:

  • One time, I saw a moth drown in a cup of water I left out overnight. After that, I didn’t leave water out unattended again.
  • I would cool down my electric hob with water after cooking, to avoid moths landing on it and burning to death.
  • I would shake my towel outside the bathroom before using it, because I knew moths liked to hide in it.[2]

Eventually, my boyfriend and I decided we couldn’t carry on like this.

I wasn’t sure what would happen if we kept doing nothing — would they eat the whole carpet and exhaust their food source? At the rate they were going, with minimal visible damage, that could take years — but we felt that we had to do something.

So — after finding a pest control company that didn’t require me to wash everything I owned, and saying a small, feeble apology to the moths on the last night of their lives, which of course they didn’t understand —

I paid a man to come to my flat and kill all of the moths. I smiled and chatted to him, and offered him coffee, while he got set up.

I had to be out of the flat while the spraying actually happened.

But when I came back… the sight made me feel viscerally sick. Dead and dying adult moths littered the floor, and walls, and surfaces.

One by one, I tried to find and euthanise the dying. I had to really work myself up to be able to do it the first time, but after a few crushed moths (the sickening ‘pop’ of their heads — or thoraxes? — is still vivid in my mind) it got easier to do.

The hardest ones to kill were those that didn’t seem sick from the insecticide, and were still running or flying, but I reasoned that killing the whole flat’s population would minimise total deaths.

…And that being killed by crushing was almost certainly better than an eventual slow death from whatever insecticide had been used.

I’d naively hoped that they’d mostly have quick deaths, despite not knowing what chemical was even used, or how it was supposed to work.

And, to be fair, it’s hard for me to observe the larvae who live in the carpet — and these are most of the population. I don’t know how quickly the larvae died, if they even are dead. I hope they died quickly.

But the adults… I think about 5-10% of the adults that I found were still alive, 5ish hours after the treatment.

And some smaller percentage (1-2%?) were still alive more than 24hrs after. All of these that I found were writhing in agony, lying on their backs with their abdomens curling arhythmically back and forth. I think what I did by paying for their deaths is as close to purposefully inflicting torture as I can reasonably imagine myself ever doing.

Today, it is nearly 3 days after the treatment, and (mercifully) I haven’t found any living adults for some time.

Why am I writing this — why did I waste your and my time with a story of such a mundane moral atrocity?

In small part, this is a public service announcement.

I think my procrastination led to many many more deaths than there would have been otherwise. If I’d have dealt with the infestation in the summer, who knows how many fewer moths there would have been to kill.

Next time I notice an infestation of any animal in my home, I will act much faster.

In small part, this is a story, for your consideration.

I think this forum is a place to share parts of our lives that result from taking our moral beliefs seriously.

It would be easy for me to feel okay about killing the moths by looking away from their suffering, or by taking solace in the lack of certainty about their sentience.[3]

I’m sort of glad I don’t do that.

But mostly, I think I wrote this because part of me naively hopes that by “confessing” the deliberate, knowing part I had in killing (torturing?) dozens or hundreds of animals, I will somehow be absolved.

…That’s not how this works, by the way. There is no absolution.

I killed the moths.


  1. ^

    I think this is because moths only eat “natural” fibres. I don’t own any clothes made of animal fibres, because I’m vegan and have been for ~10 years. I’ve read that moths can sometimes eat cotton, but for whatever reason, these moths definitely didn’t eat my clothes!

  2. ^

    You might worry about the hygiene implications of this. Actually, adult carpet moths don’t eat, and IIUC they also don’t excrete. I also couldn’t find any evidence of them being disease vectors. And, as I mentioned, they seemed to only lay eggs in my carpet. So I accepted their little fuzzy presences even on my towel :)

  3. ^





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I guess I feel a lot of things:

  • Empathy - I try to save slugs and snails etc, so I get this feeling that we should take all lives mattering seriously. There is something caring and beautiful in this and I like this intuition
  • Confusion - I have felt this about veganism a bit recently. I don't really think it's worth the amount of stress it caused me to be vegan in terms of animal lives saved. Perhaps I should do it for a month a year to remind me of the cost, but I until I hit diminishing returns on my work I should probably do that. I used to think "if I were in slave owning times I should have divested entirely" but I dunno these days. Probably my anti-slavery resources were better spent first and foremost funding abolitionists. I don't know the exact costs
  • Frustration - I find this story sort of a bit insane. It's about someone I know who is very kind tying themselves in knots over over a few hundred hours of micro-consciousness. I have a voice of a friend in my head being like "that's an insane story" and for myself I'd allow it a bit but at some point I think I'd say that it isn't the best way to help moths or all consciousness and that most minds would agree with the parts of me that want to throw in the towel
  • Sadness - I'm sad that you are sad, especially after trying to be so kind. And I agree that it's weird how we behave to people who we maybe think are doing bad things like the insect guy. 

"I used to think "if I were in slave owning times I should have divested entirely" but I dunno these days. Probably my anti-slavery resources were better spent first and foremost funding abolitionists. I don't know the exact cost"

- I appreciate this level of honesty and skepticism ❤️

I'm sorry that you had to go through this terrible event, but thanks for writing this - I found it really moving and I think the lesson is a good one. I think you conveyed the value of moth wellbeing, and your respect for it, in a touching way.

Thanks for writing this, Bella. I relate: I lived with mice recently and spent a lot of time fretting about their well-being as the landlord closed in.

I think that sympathy towards small, liminal animals speaks to an expanded moral circle and that, when we feel powerless to save the animals, bearing witness to their deaths as you've done here might be an important way of paying respect to them.

If the lives of pests are net negative,* I think a healthy attitude is to frame your natural threat/disgust reaction to them as useful. The pests you see now are a threat to all the future pests they will create. It's imperative to the suffering of those future creatures that the first ones don't live to create them. Our homes are fertile breeding grounds for enormous suffering. I think creating these potential breeding grounds gives us a responsibility to prevent them from realizing that potential. 

I take the central (practical) lesson of this post to be that that responsibility should spark some urgency to act and overcome guilt when we notice the first moth or mouse. We've already done the guilty thing of creating this space and not isolating it. The only options left are between more suffering and less.  

Thank you for the post!


*I mean this broadly to include both cases where their lives are net negative in the intervention-never scenario and in (more likely) scenarios like these where the ~inevitable human intervention might make them that way. 

I wonder whether the lives of those moths were net negative. If the population was rising, then the number of moths dying as larvae might've been fairly small. I assume that OPs apartment doesn't have many predatory insects or animals that eat insects, so the risk of predation was fairly small. That leaves five causes of death: old age, hunger, thirst, disease and crushing.

Death by old age for moths is probably not that bad? They don't have a very long life, so their duration of death also doesn't seem very long to me, and couldn't offset the quality of their life.

Hunger and thirst are likely worse, but I don't know by how much, do starved moths die from heart problems? (Do moths have hearts?)

Disease in house moth colonies is probably fairly rare.

Crushing can be very fast or lead to long painful death. Seems the worst of those options.

I think those moths probably had a better life than outside, just given the number of predatory insects; but I don't think that this was enough to make their lives net-positive. But it's been a while since I've read into insect welfare, so if most young insects die by predation, I'd increase my credence in those moths having had net-positive lives.


I think it's right to at least be open minded about the possibility that their lives might be generally good, all things considered.

To answer your question: insects don't have hearts because they don't have blood. Oxygen is transported to their cells by many tiny tubes (tracheae) extending from holes (spiracles) all over their thorax and abdomen.

Thanks for sharing this. I had a similar experience recently in which I treated a wool carpet with cypermethrin (an insecticide widely used to kill clothes moths). This or a similar compound is likely to be what was used in your case as well. It is relatively safe in humans and many mammals in the concentrations present in pest control products. 

Its mechanism of action is to bind with and disrupt sodium ion channels in the central nervous system of insects. It causes excessive firing of neurons and death. 

My suggestion to reduce infestations of moths and eventual suffering is to pre-treat natural fibres which are not washed regularly (like carpets) with a cypermethrin (or other pyrethroid) containing product at around 0.1% concentration. These will act as repellents and prevent the reproduction of moths before they become established and prevent future suffering. It should only be used indoors to prevent exposure to non-pest species as it is broadly toxic to insects and many vertebrates. These products are widely available on Amazon. 

(PS these products might be more toxic to cats for some reason. Bear this in mind when using them)

Hey Sam — thanks for this really helpful comment. I think I will do this & do so at any future places I live with wool carpets.

Thanks for sharing, it sucks that you went through this (and sucks that the moths went through this :( ). As uncomfortable as thinking about these topics is, I am glad to be part of a community of people who take ethics seriously and try to act with compassion and consideration. Let's hope market forces take effect and enough people inquiring about low-suffering ways to kill insects creates a market for companies to offer this :)

I had to deal with this about a year ago and ended up setting sticky traps that would also lure them in. I'd then check the traps periodically and crush them while they were alive and writhing. I can't tell if this is a better option though?

Separately, I'd like to see more content like this on the forum. I'm sure many of us have had thoughts / experiences like this!

My prior would be that unless you check extremely frequently, this sounds like a lot of suffering. But not sure about the other options.

I'd like actual feedback on this approach if anyone has any. Where is Brian Tomasik when you need him.

I wrote a post on moth traps. It makes a rather different point, but I still figure I'd better post it here than not. 

I've got moths in my flat right now and this post made me take solving this more seriously. Thank you!

This post was moving, thank you for writing it. I have dealt with a similar situation, and found it impossible. I've dealt with that impossibility by trying to justify what I've done, and absolve myself. Your post is forthright: you killed the moths. We can move on from it, but we don't need to rationalize it.

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