This is the third of a four-part series of blog articles exploring how I can practice non-violence against insects in my day-to-day life. The first post offered some brief notes on insect abundance in artificial turf sports pitches (as opposed to grass pitches). The second post made some rough calculations to estimate the number of insect killed by driving.

Summary

In this post, I highlight two ways that everyday life can cause direct suffering to sentient animals: by hitting insects with the car while driving, and by stepping on grass where invertebrates live.
While the evidence base isn’t perfect, I offer some rough calculations for the numbers of invertebrates killed by both of these processes. I apply those calculations to a specific decision in my life: choosing which of two soccer clubs I should play at for the 2026 season.
All else being equal, playing at a club that trains and plays on artificial turf rather than grass probably kills fewer insects (in the ballpark of a million insects or so). Likewise, playing at a club that is closer to my house and/or catching the bus probably kills fewer insects (in the ballpark of tens of thousands of insects or so).

(In this post, I use the words “insect” and “invertebrate” mostly interchangeably. The correct term is “invertebrate”, a broader group of animals that also includes non-insect critters like spiders and slaters. But most of the invertebrates you see in your day-to-day life are insects, and more non-expert readers will be familiar with the term “insect”, so I have mostly used that term for this post.)

Driving distance

The first thing to consider is driving distance. In a previous blog post, I concluded that if you drive for 1 km, you can expect to hit ~1.5 - 90 insects with your car, though there is significant variation around that estimate.

This means that, all else being equal, a nearby soccer club is preferable to a distant club.

Some clubs play home matches at a ground separate from their training ground, so we need to consider both the home ground and the training ground. Also, you can expect to drive to the training ground (around once a week throughout the season) more frequently than the home ground (around once a fortnight throughout the season, as half of all matches are away at other clubs).

For the 2026 season, I’m choosing between two clubs: Club A and Club B. These are actual clubs near my house, but I’ve given them fake names because I’m posting this online. As a comparison, I’ll also consider futsal—as this is indoors and usually in a single location throughout the season, this would be form of soccer least likely to hurt insects.

Club A

Training: 1.4 km from my house
Home matches: 1.4 km from my house
Away matches: Variable distance from 1.4 km to 30 km, with most within the 5-15 km range

Club B

Training: 7.1 km from my house
Home matches: 4.3 km from my house
Away matches: Variable distance from 1.4 km to 30 km, with most within the 5-15 km range

Futsal:

Training (if any): 6.5 km from my house
Matches: 6.5 km from my house

We can assume a season of ~25 trainings and ~22 matches (split equally between home matches and away matches), though futsal would likely have more like ~3 trainings at most. For those variable away matches, I’m comfortable assuming an average distance of 8 km.

Thus, distance travelled throughout the season for each club (each trip is multiplied by 2, as I need to drive home after soccer!):

Club A:
$(25\times2\times 1.4) + (11\times2\times 1.4) + (11\times2\times 8)$
$= ~280 km$

Club B:
$(25\times2\times 7.1) + (11\times2\times 4.3) + (11\times2\times 8)$
$= ~630 km$

Futsal:
$(3\times2\times 6.5) + (22\times2\times 6.5)$
$= ~330 km$

This indicates that playing for Club A would cause me to drive ~280 km throughout the season, Club B ~630 km, and Futsal ~330 km.

There are two caveats that apply to me personally.

My wife has agreed to play and coach for Club A already. This means that, from the perspective of my own personal decision-making, driving to Club A for trainings and matches is “free”—I simply hop in the car that my wife will be driving there anyway.
I could catch a bus rather than driving to Futsal, and possibly to the trainings and home matches for Club B.

This means that, if I take all possible actions to reduce my driving distance, then the distance driven throughout the season would be more like:

Club A (driving with wife):
$= 0 km$

Club B (using bus where possible):
$(11\times2\times 8)$
$= ~180 km$

Futsal (using bus):
$= 0 km$

And since we have previously estimated that a car hits ~1.5 - 90 insects per km, we can calculate the number of insects who are hit by my car due to each choice. In practice, I think it’s certain that I would drive with my wife for Club A; it’s possible but not guaranteed that I would use the bus where possible for Club B; and it’s likely that I would use the bus for Futsal. So:

Club A (driving with wife):
$= 0 insects$

Club B (driving):
$630\times (1.5 to 90)$
$= ~950 to ~57,000 insects$

Club B (using bus where possible):
$180\times (1.5 to 90)$
$= ~300 to ~16,000 insects$

Futsal (using bus):
$= 0 insects$

So, for me personally, I can expect to hit with my car:

0 insects if I play for Club A
0 insects if I play Futsal
~950 - 57,000 insects if I play for Club B and drive
~300 - ~16,000 insects if I play for Club B and use the bus where possible

Stepping on grass

Some soccer pitches are made of real grass, while others are made of artificial turf. Club A’s pitches are real grass, while Club B’ pitches are artificial turf.

In a previous blog post, I began to explore whether there is a difference in the number of insects who live in grass versus artificial turf.

If there are more insects living in real grass than in artificial turf, then stepping on real grass is likely to crush more insects than stepping on artificial turf. If this is the case, then it might be morally preferable to play for a club that has artificial pitches.

Why player caps are not important

A caveat: during a soccer match, there are always exactly 11 players from any given team on the pitch. You could argue that this specific team size means that a single player doesn’t actually cause any additional grass-stepping, as you’re really just adding +1 player to the bench rather than the pitch. But I think this conclusion is wrong for three reasons.
1) This doesn’t apply to training, where there are no caps on the number of people participating at any one time.
2) Even a bench player warms up, walks on the grass while hanging out at the sideline, and so on.
3) In rare instances, adding a player to a team will actually cause the team to split into two teams, which would drastically increase grass-stepping.

So, I think it’s fair to treat +1 player on a team as simply +1 person stepping on the grass.

Estimates of insect numbers in grass

This means that the important question is: how many invertebrates live in the grass of soccer pitches?

While answering this question, it’s important to keep in mind that soccer pitches are not the same as grass in general. Soccer pitches receive very heavy foot traffic and are often treated heavily with pesticide, mowed regularly, sprayed with paint, and so on. This means that estimates of invertebrate numbers in other grassy areas (e.g., “natural” areas, backyard grass, etc) might not be representative of soccer pitches.

With that caveat in mind, here are some rough numbers of invertebrate abundance in grass from published ecological surveys. There’s lots of variation because different surveys used different methods in different parts of the world. Also, this is just a haphazard collection of papers I found using an informal search on Google Scholar rather than a systematic literature review (which would take weeks). But most surveys actually seem to give answers in the same ballpark.

Estimates from inside Australia:

~460 insects in each trap, with three traps per 3.6 m² plot, suggesting ~380 insects/m² figure 1a
An average of 2,865 insects were found by sampling mostly unmanaged grasslands - the area sampled is unclear, but this project is particularly relevant as it was conducted near where I live https://onlinelibrary.wiley.com/doi/pdf/10.1155/2014/202056 table 4
40,897 invertebrates found in 20x 0.25 m² plots in parks in New Zealand (which isn’t in Australia, but close enough) - indicating ~8,200 invertebrates/m² https://link.springer.com/content/pdf/10.1007/s11252-025-01728-0.pdf table 2

Estimates from outside of Australia:

44k - 6M insects in a 0.2 acre lawn, indicating ~55 - 7,500 insects/m²
45,447 insects were found from ~11 circles of ~3m diameter, indicating ~1,600 insects/m² in short rye grass in England (an underestimate due to the methdology) (Table 4.4, control group)
Several thousand insects were found in the average ~112m² plot of experimentally managed grassland in the United States, indicating dozens or hundreds of insects/m², though it’s hard to give an exact number due to the methodology
~100 - 200 insects per 0.36 m² turf plot in England, indicating ~420 insects/m² (though this was over multiple sampling periods?) (Figure 1A)
An average of ~1,000 invertebrates recorded per domestic urban garden in England, though the area sampled is unclear
271 bees, wasps, and flower flies found in residential lawn in Canada, though area is unclear (Table 2)
~35 invertebrates in each sample of soil in urban tree habitat, not really useful for us except for the finding that inteverbrate abundance was higher 1-2 cm deep in the soil than 0-1 cm deep.

So, most studies generally indicate several hundred to several thousand invertebrates per m² of grass.

Estimates of insect numbers in artificial turf

In my previous blog post, I complained that no published study—at least as far as I could tell—had measured the abundance of invertebrates in artificial turf. Most authors agree, based on ecological theory and anecdotal observations, that the abundance of invertebrates would be lower in artificial turf than in grass. But nobody has tested this empirically.

Estimates of insect numbers indoors

I assume that there are zero, or very few, insects living on indoor Futsal pitches. It’s possible that there are a few insects who find their way indoors. But I think that a) these will be very few, and b) the number is probably comparable to the number of insects hanging around in my own kitchen, which is likely where I’ll be hanging out if I don’t play any sport!

How much grass might you crush while playing soccer?

So we’ve got some reasonable estimates for invertebrates in each m² of soccer pitch. But we need to convert this to numbers of insects crushed.

My feet are size 11 UK / 12 US in men’s sizes. This means the sole measures around 30 cm long and around 10 cm wide; that is, 0.03 m².

How many times do I step on the ground while playing soccer? Two internet users here indicate ~10,000 - 20,000 steps.

Professional men’s goalkeepers cover ~5 km in a match (source). I’m neither professional nor a man, but I do like to wander pretty far out of my penalty box to protect my team from through-balls—so let’s call this 3 km. If my average stride is 80 cm, then this equates to ~3,800 steps per match. I’m ignoring the fact that I often fall into the ground (which means more area covered).

This means that I can expect to step on:
$3,800\times 0.03$= 1,125 m² $$

What about during training rather than a match? Honestly, I think the estimate would be fairly similar. I work very hard in training — sometimes, I work harder in training than in the match itself. Trainings also last for a similar amount of time (80-90 minutes). So, I think it’s fair to assume that the number of steps at training will be the same as the number of steps in a match.

Bringing it all together

If I step on a particular section of grass, would I kill all the insects in that grass? Probably not. I have no idea what percentage I would kill. I think it’s less than all of them, but more than none of them. As a guess based on my intuition, let’s call it 5%.

Therefore, we can combine our estimates of ~1,000 insects/m², 1,125 m² covered/match, and 5% of insects crushed:
$= 1,125 \times 1,000 \times 5%$
$= ~50,000$

That is, ~50,000 grass-dwelling insects crushed per match.

For Club A, over our season of ~25 trainings and ~22 matches (assuming that ~4 of those matches are played away at artificial pitches), this is equivalent to:
$50,000\times (25 + 18)$
$= ~2,000,000$

For Club B, if we restrict our attention to just the matches played on grass, we can expect to play 9 away matches (11 away matches in total, minus ~2 that are played at other clubs’ artificial piches):
$50,000\times 9$
$= ~450,000$

That is, playing for Club A would crush around 2 million grass-dwelling insects insects by walking on grass throughout the season. For Club B, this number is more like 450 thousand.

This is highly sensitive to the input assumptions, especially that ~5% guess for the number of insects crushed by stepping on grass.

It’s also possible that most insects are crushed very early during a match and subsequent steps are only crushing already-dead insects. If this is true, then my above estimate will be too high.

Now, we can combine these numbers with our earlier estimates of insects killed by driving:

Club A: 0 insects hit by car + ~2 million grass-dwelling insects crushed underfoot = ~2 million insects in total
Club B (if I drive): ~950 - 57,000 insects hit by car + ~450,000 grass-dwelling insects crushed underfoot = ~480,000 insects in total
Club B (if I use the bus where possible): ~300 - 16,000 insects hit by car + ~450,000 grass-dwelling insects crushed underfoot = ~460,000 insects in total
Futsal: 0 insects hit by car + 0 grass-dwelling insects crushed underfoot

Currently, Club A looks worst, followed by Club B, with Futsal obviously coming out on top.

But those numbers do not include artificial-turf-dwelling insects who are crushed underfoot. In what situation would Club A look better than Club B? For this to happen, the number of artificial-turf-dwelling insects crushed underfoot would need to reach the ballpark of ~1.5 million, which is 75% of the number of grass-dwelling insects crushed underfoot while playing for Club A. Using the same assumptions around distance travelled and foot size above, that condition is met if the abundance of insects in artificial turf is at least ~75% the abundance of insects in grass.

However, it is probably true that artificial turf contains less than ~75% the abundance of insects in real grass, at least if you accept the anecdotal experience and ecological theory that passes for empirical evidence on this topic.

But this hypothesis is also pretty easy to test—all you have to do is take a microscope camera to an artifical turf pitch (as well as a grass pitch for comparison) and record some footage of the invertebrates, if any, who live on/in the ground. I have a microscope camera, so I will in fact test this hypothesis—but since I must time my trip well in order to access the artificial turf pitch near my house, this will need to wait for a future blog article.

Counterpoint: Does stepping on grass actually kill bugs?

An underlying assumption for this whole analysis is whether stepping on grass actually kills bugs or not.

I think the answer is: Yes, stepping on grass kills bugs. But I’m not 100% sure—while the weight of the evidence base seems to point towards that conclusion, I haven’t yet seen the “smoking gun” evidence.

Much of the discussion on this question is anecdotal. Adherents of the religion Jainism avoid stepping on grass precisely because they think that doing so crushes insects, as Jains usually practice non-violence (an attitude and lifestyle that I wholeheartedly endorse). There are also many online forums, often debating veganism, where forum users argue about whether or not stepping on grass kills bugs—there seems to be a general agreement that stepping on grass kills bugs at least sometimes, but as is often the case in online debates, empirical evidence is not forthcoming.

Some relevant empirical sources are:

Ciach et al 2017 found lots of crushed invertebrates on hiking trails, indicating that stepping on bugs can directly kill them. The trails were “covered with a mixture of soil, rock or rock debris, and natural vegetation was present adjacent to the path” - so they’re not grass trails, but there is grass on the side of the path.
Ayres et al 2008 looked at invertebrates in Antarctica (obviously not representative for sports pitches!) and found that trampling increased the ratio of dead-to-living invertebrates. This doesn’t rule out decreased breeding rather than increased deaths, as the authors point out.
Duffy (1975) showed that trampling on grassland litter (not the same thing as a sports pitch, but similar) causes a decline in the abundance of invertebrates. This is consistent with the hypothesis that trampling on grass directly kills invertebrates. However, it’s also possible that the observed decline in abundance is due to other factors, such as less resource or space availability meaning that insects breed less, rather than being killed directly.
This environmental impact assessment from a Scottish transport company (?) addresses invertebrates: “Trampling by humans can also cause direct mortality […].”

So, the weight of the evidence pushes me towards accepting that stepping on grass indeed directly kills insects. But this isn’t a slam-dunk; it’s possible that stepping on grass doesn’t actually kill insects, as I haven’t yet seen a direct empirical test of this hypothesis.

Is it good to kill insects if it decreases their population, and thus causes fewer insects to be born? Brian Tomasik seems to think so (if I’ve interpreted his views correctly). I generally have a lot of respect for Tomasik’s work, and I endorse many of his views. But I don’t endorse this paticular view, or at least not strongly. This hinges on some very murky areas of philosophy and welfare science, such as which moral theory is correct, whether anti-natalism is correct, and whether wild insects live “net good” or “net bad” lives in aggregate (or whether such a question is even coherent to ask). Much debate has raged about such questions. Currently, I don’t feel confident enough in any such argument to endorse the view that it’s good to kill insects in order to decrease their population size.