Summary/TL;DR

I argue that every sentiocentric antinatalist should care about not creating fruit flies, by showing that even what I call Minimally Demanding Sentiocentric Antinatalism poses such a requirement. As the argument goes, even if we should only refrain from the unneeded relatively direct creation of sentient beings, and if children prima facie count as one of them, sentiocentric antinatalists have a moral duty not to take actions that would result in the creation of fruit flies. I base my argument on the plausible axioms that creating fruit flies is unneeded, the formation of fruit flies is the result of a relatively direct act or abstaining from such an act, analogous to the creation of children, and above all the fact fruit flies satisfy numerous criteria for sentience (see Gibbons et al., 2022, EA summary), so it is reasonable to assume they are sentient, or it is reasonable to invoke the ethics of uncertain sentience/precautionary principle in their case. Abstaining from actions that would lead to the creation of fruit flies may save hundreds to thousands of subjective years of fruit fly lives, and in expectation reduces disvalue. Therefore it is a serious moral issue despite maybe looking funny or unworthy of consideration. I also briefly mention some other ways in which our everyday actions may impact invertebrate multiplication.

Introduction: Antinatalism and non-human animals

Sentiocentric antinatalism (hereinafter: SAN) claims that coming into existence constitutes harm to every sentient being. For the purposes of this introduction, this strong version of SAN will be adequate, but I believe even the weak version of SAN - coming into existence is a harm only if the life created is sufficiently bad - might suffice. It may be enough to state that (strong) sentiocentric antinatalism is a view defended by David Benatar, many well-known antinatalists and a large part of the antinatalist community, and it does not struggle with the problem of setting an arbitrary moral boundary between humans and non-human animals, thus not exposing itself to the charge of speciesism.

Despite the fact that many antinatalists consider themselves sentiocentric, often considerations of non-human animals do not occupy a proportionate position in antinatalists’ worldviews, to the point of being commonly ignored. This may be partly due to a sense of lack of influence, and partly due to the lack of adequate representation of the problem. The following text is not intended to address this problem, but to draw attention to one aspect of it, related to our impact on the existence of fruit flies.

The case for fruit fly antinatalism

From the perspective of both consequentialist and non-consequentialist SAN, conscious action to produce a new sentient being is immoral, in some cases assuming we're not expecting the new life to have sufficient instrumental value. In practice, it usually leads to abstaining from conceiving children. From the utilitarian AN perspective, since utilitarianism is often a very demanding ethical theory, the set of obligations is much broader. For the purposes of this text, a weaker set of obligations is sufficient though.

My focus on fruit flies stems from several reasons. First, they are, sadly, once again a perfect model organism, allowing us to easily show the moral aspect of the SAN in relation to non-human consciousnesses. Then, they shed light on the suffering of invertebrates which, despite making up 99.9998% [see Bar-on et al., 2018] of the animals on the planet, receive not even a fraction of the moral attention they deserve. Thirdly, not only are fruit flies common, being known to all of us, but also preventing their creation and multiplication in their case is relatively simple.

The criteria

Let's look at the criteria that must be met for even a very morally undemanding sentiocentric antinatalism, limited only to abstaining from unneeded relatively direct creation of sentient beings, I will call this view Minimally Demanding Sentiocentric Antinatalism (MDSAN), to require abstaining from causing the existence of fruit flies.

1. Creating fruit flies is unneeded.
2. The formation of fruit flies is the result of a relatively direct act or abstaining from such an act, analogous to the creation of children, prima facie considered immoral under antinatalism (so also MDSAN).
3. Fruit flies are sentient beings, or it is reasonable to assume they are, or it is reasonable to invoke the ethics of uncertain sentience/precautionary principle in their case.

(1)

Let's start with the first criterion. An initial point that may be important to clarify is the difference between unneeded and unnecessary. Some AN (e.g. consequentialist AN) may justify the creation of sentient beings because the instrumental value of their existence outweighs the disvalue of their creation. We may consider some acts of creation or allowing sentience to be necessary, and thus the act of creating them may be morally justifiable or obligatory. Another group of creations would be those that are somehow needed but not necessary. Necessary acts could be "strongly needed", but there would also be acts "weakly needed" - that is, useful to some extent. I leave open the question of how morally justified such acts of creation are, in principle they seem unjustified to me. However, we can assume that within minimally demanding SAN, the creation of some merely useful creatures is allowed. While the creation of some sentient beings has an instrumental value, although the vast majority of such creations I believe (as most of these instrumentally created lives are probably farm animals) is unwarranted, it allows MDSAN to create some whatever needed/useful beings. But there are also beings whose creation is instrumentally unneeded, and even instrumentally troubling.

Fruit flies are unneeded because their existence does not meet the criteria of having important instrumental value. They do not improve the well-being of other sentient beings, nor do they cause any other clearly positive states, although in the paragraph below I present suggestions for such possibilities. Most often, flies are either completely neutral or have a negative impact on human well-being, causing annoyance by large numbers of flies, discomfort by having to eat or throw away infected fruit, and if they are thrown away - the loss of money paid for the fruit and the lack of comfort of eating it, as well as failure to provide the body with an additional portion of vitamins. The discarded fruit can also become food and a breeding ground for other sentient beings that would not have arisen in such quantity without it. The existence of fruit flies in house conditions has no instrumental positive value, so creating them, if the following criteria are met, is unjustified from the perspective of the MDSAN, and therefore also any other SAN.

Certain situations in which the existence of fruit flies has an instrumental value in domestic conditions can be imagined. For example, fruit flies provide food for house spiders, thereby reducing the discomfort of their hunger. However, given that a) house spiders also feed on other insects, and the flies are not necessary for them, but merely useful for survival, b) the spider's death by starvation seems less bad than its life paid for by many flies being dissolved by spider’s venom and c) that such feeding of spiders consequently leads to their reproduction, and thus to more suffering for spiders and their prey, the existence of flies as food for spiders is not an argument for creating them, because the disvalue of their suffering outweighs their instrumental usefulness. Another aspect of the usefulness of the flies is that their appearance reminds us to eat the fruits quickly, thus preventing food from spoiling and being thrown away, perhaps at the expense of only a small number of flies. This is related to another argument, which I will call the need to avoid discomfort. It may be argued that preventing the proliferation of fruit flies is an additional chore, being an inconvenience that reduces the comfort of human life. In this sense, not preventing the emergence of flies by creating conditions for their multiplication is needed so as not to burden us with additional tasks and not to complicate everyday functioning. It may be argued that MDSAN should not require us to sacrifice our own comfort for such a "trivial" activity as not causing fruit flies to multiply. However, I believe this argument is wrong. The potential discomfort of investing energy in not contributing to the formation of flies seems negligible compared to the amount of suffering and instances of coming into existence that could be prevented. Weighted against the cumulated discomfort of all stress, pain and agony that may be experienced by at least thousands of fruit flies, our discomfort looks like a minor inconvenience it in fact is. Especially given that avoiding leaving uneaten fruits for too long is associated with benefits - we avoid the discomfort of dealing with flies, we acquire healthy habits of self-control, we throw away less food. Eating fruits before the flies appear on them quickly becomes a habit, being only a very temporary discomfort. It also helps us to reduce our direct impact on the suffering of invertebrates in daily life, an impact of non-negligible absolute importance, even if the relative impact of such an approach may be negligible. What matters, however, is the suffering of particular individuals, which does not change whether there are 10 or 10 billion individuals. From the SAN perspective, any emergence of a conscious being is a tragedy, and being able to stop that tragedy at low, virtually negligible cost, or even to your own benefit, requiring you to do so is, in fact, minimally demanding. “Minimally” is also a key word in this context, because MDSAN does not mean the absence of any requirements. In the absence of requirements, it can be argued that if someone is mildly uncomfortable not having children or not creating conscious programs, abstaining from doing so should not be required of them. Treating the suffering of flies differently does not seem justified.

(2)

The second criterion is responsibility for the formation of fruit flies. The similarity between the creation of a child, i.e. causing a child to come into existence, and causing a fruit fly to come into existence is, I argue, a tenable analogy. A true analogy must be characterized by both significant similarity and no significant differences, both of these criteria are met in this case. Even limiting the practical moral requirement for antinatalists only to not creating children, the creation of a sentient mind is not the direct result of an act. It is either a risked, foreseen, or, depending on the situation, practically unavoidable consequence of another intentional act (the sexual act or artificial insemination, which leads to the development of an organism in which sentience itself does not arise until later) or an act from which we refrained (contraception, abortion). This presentation of the matter provides a morally relevant analogy on which I wish to base my argument. I argue that a sentiocentric antinatalist who recognizes even a minimal moral obligation not to create sentient beings relatively directly (as we've seen, even the creation of a child is not technically a fully direct act, but a consequence of another act or abstaining from certain acts) is obliged not only to refrain from making children. They also have the responsibility not to create other sufficiently unneeded (or, ideally, unnecessary) sentient lives. This means, for example, not causing pets to bear offspring,  which is a fairly common claim, but also not contributing to the creation and multiplication of fruit flies. Between the creation itself of human life and fly life there seem to be no morally significant differences, although the differences may concern the negative value of this future life (which could be greater in "more" sentient humans) and the instrumental value (zero or negative in the case of flies, questionable in the case of humans [people cause suffering, e.g. to farm animals and other people, but they can also reduce their suffering, and their existence results in the degradation of ecosystems and prevents the future creation of a large number of wild animals (see Tomasik, 2016; Vinding, 2021)], and there are morally significant similarities between them - both result in a creation of a sentient being for whom it will be a harm.

(3)

Fruit fly sentience: The third criterion that must be met is that fruit flies have to be considered (at least plausibly) sentient beings. There is now convincing behavioral and neuroanatomical evidence for the consciousness of insects, particularly fruit flies. As demonstrated by Gibbons et al. (2022) (EA summary) in a paper examining the evidence for insect consciousness, flies in adult stages satisfy at least 6/8 criteria for sentience. This is more than lobsters and other decapods, generally considered sentient. In addition, research on insect consciousness is still in its infancy, which leads us to believe that more criteria for sentience may be met by insects in the future. In addition, fruit flies have nociceptors, at least in larval states, that have so far only been detected in a small number of insects (perhaps because of little research), which allows us to further increase our credence that they can feel pain. The evidence therefore tells us to assign a significant probability to insects possessing sentience, although we cannot yet be absolutely sure. However, absolute certainty is not necessary. Based on probability and the ethics of uncertain sentience, a form of the precautionary principle (see: precautionary principle in animal sentience), we should avoid creating beings that we suspect may be sentient. The strength of this requirement may depend on the probability assigned and the strategy adopted, but as long as this probability is non-negligible and our effort is negligible, MDSAN also implies refraining from relatively directly allowing for the emergence of fruit flies.

An argument against moral consideration of  fruit flies would be to assume that the sentience intensity of fruit flies may be low, and thus people's preference for convenience easily outweighs it. In fact, however, we have no other than intuitive reason to believe that the mental states experienced by simpler organisms are less intense [see Vinding 2022], and our intuitions repeatedly turn out to show a model of reality that is inconsistent with the facts. Even if the mental states of fruit flies were less intense, this does not entitle us to disregard them. Guided by the ethics of uncertain sentience and precautionary principle, we should also recognize that it is better not to be responsible for the emergence of the flies, since their mental states can, with a non-negligible probability, be morally significant enough. The last, very important aspect of the whole problem is the number of fruit flies for which we can be responsible, or whose existence we can prevent. Over the course of the rest of our lives, this may be tens of thousands of individual sentient beings prevented from coming into existence. An adult female fruit fly can lay up to 500 (usually 400) eggs on the surface of moist and rotting fruits, which hatch within 12 hours. Tiny maggots - which we should also consider possibly sentient, according to Gibbons et al. (2022) Diptera (the order where flies belong) larvae satisfy at least 4-5/8 criteria for sentience - hatch and start to eat the decayed food. Within 4 days, they're all grown up and shortly after ready to mate, too. The average natural lifespan of fruit fly adults in optimal temperatures is 40 to 50 days (different sites provide different lifespans, but for the back-of-an-envelope calculations I perform it’s not so importnat). This gives many thousand days of fly life, the quality of which we can assess differently. Most likely it is not filled with joy, but at most with neutral satisfaction of needs, and with moments of hunger, fear, thermal stress, aggression, and frustration related to the impossibility of reproduction, ending with death in a spider's web, of hunger, drowned in juice, or otherwise killed by a human trying to get rid of them, their deaths not being instant in most cases. Even the assumption of low probability and low intensity of their sentience seems insufficient to ignore the problem of allowing for fruit fly emergence and multiplication. Assuming the average lifespan of fruit flies to be much shorter, only 10 days, if we imagine 10,000 fruit flies (a number which does not seem to be an exaggeration) a year would have been created given we don't prevent it, we may be responsible for creating 274 subjective years of fruit fly life. If our actions (e.g. for the rest of our lives) would cause 100,000 flies to come into existence, and if their average lifespan is longer (e.g. 30 days), we get over 8 thousand years of sentient experience, plausibly slight to intense disvalue, created. This simplified calculation sheds light on the scale of the problem, and the impact our actions really have. All of that doesn't even touch on the suffering of future generations of wild fruit flies that may follow from the ancestral lines we relatively directly created. We may further modify those examples, claiming fruit fly sentience counts as only slightly negative, but plausibly there is enough of a disvalue taking place for us to take action against allowing fruit flies to reproduce. It seems implausible at best and wishful thinking at most that the disvalue of the suffering of fruit flies is incidentally at precisely such a low level to be easily outweighed by our need for not experiencing a really slight inconvenience.

Thus, the creation of fruit flies in a situation where a) their existence is unnecessary and unneeded, b) their existence is caused by intentional or unintentional relatively direct act or omission, c) when we have good reasons to believe that the flies are sentient, and to act on the basis of ethics of uncertain sentience, is morally reprehensible from the perspective of even minimally demanding, and therefore every sentiocentric antinatalism. Sentiocentric antinatalists should at least not allow fruit flies to emerge and refrain from actions that will lead to their multiplication.

How to prevent fruit flies?

Preventing the formation of fruit flies is minimally demanding, at the cost of just a few activities we can prevent their emergence or significantly reduce their number. Chat GPT and various sites on the internet give the following, intuitive advice:

• Store fruits and vegetables properly:
• Keep ripe fruits and vegetables in the refrigerator.
• Store unripe fruits at room temperature until they ripen, then move them to the fridge.
• Use fruit bowls with lids:
• Cover fruit bowls with a mesh or netted lid to prevent flies from accessing the fruits.
• Keep countertops clean:
• Wipe down kitchen countertops regularly to remove any fruit residue or spills that may attract fruit flies.
• Dispose of overripe or rotting produce:
• Regularly check for and discard any overripe or rotting fruits or vegetables in your kitchen.
• Empty trash bins regularly:
• Fruit flies can breed in your trash, so empty it regularly and use a trash can with a tight-fitting lid.
• Rinse recycling containers:
• Clean recyclables before placing them in recycling bins to remove any food residues.
• Clean drains:
• Fruit flies can breed in damp and organic material in sink drains. Use a drain cleaner or vinegar to clean and maintain your drains.
• Seal food containers:
• Use airtight containers for storing grains, cereals, and other pantry items to prevent access for fruit flies.
• Clean kitchen appliances:
• Regularly clean your kitchen appliances, like blenders and juicers, to remove any leftover fruit residues.
• Cover fermenting or decaying items:
• If you're brewing kombucha, making homemade wine, or composting, ensure that these items are covered to prevent fruit flies from getting in.
• Maintain cleanliness in pet areas:
• Clean pet food and water bowls regularly to prevent attractants for fruit flies.
• Keep windows and doors closed:
• Make sure your doors and windows have screens to keep fruit flies from entering your home.
• Dispose of garbage properly:
• Make sure outdoor garbage cans have tight-fitting lids to prevent fruit flies from breeding in your trash.
• Use vinegar traps:
• Create DIY vinegar traps by placing a small dish with apple cider vinegar and a drop of dish soap near fruit fly-prone areas. Cover the dish with plastic wrap and poke small holes in it to trap the flies. [It prevents more flies from coming into existence while their potential parents already hatched. This seems to be the most popular method, but I would strongly suggest causing flies to die instantly, rather than a slow and probably very distressing death. The best way when the flies already hatched might be to mechanically kill every fly, crushing it instantly to disintegrate its nervous system. Then, the infected fruit should be eaten immediately or otherwise (e.g. thermally?) deprived of the larvae, otherwise more flies will hatch. Throwing away such fruit will not prevent the formation of flies.]
• Regularly clean and sanitize:
• Maintain a clean kitchen by wiping down surfaces, cleaning spills immediately, and regularly sanitizing areas where fruits and vegetables are prepared and stored.
• Remove compost regularly:
• If you have a compost pile or bin, empty it regularly to prevent fruit fly breeding.
• Fix any leaks:
• Repair any plumbing leaks as fruit flies are attracted to damp areas.

Conclusion

Fruit flies are an obvious example of organisms that we have a relatively direct influence on. Our act or inaction in a small number of steps leads to the emergence of sentient life. The case of fruit flies is in a way special, as their existence is actually unneeded, and preventing or limiting their formation is relatively simple (we treat simplicity of implementation as an aspect of the need for convenience). Minimally Demanding Sentiocentric AN therefore requires not creating fruit flies. However, it seems that MDSAN is not a plausible moral stance under sentiocentric antinatalism. It does not seem that the creation of sentient beings as a result of taking care of one's own comfort should be morally justified. In that case, antinatalism would lose its practical sense, allowing for the creation of any minimally needed beings, including children and non-human animals bred for food, and we would, prima facie, like antinatalists not to create e.g. children for self-centered reasons. Assigning a low value to the mental states of insects may balance this inequality, allowing them to be created as a result of our convenience, but in the face of modern knowledge, this seems to contradict the precautionary principle and ethics of uncertain sentience, as well as the utilitarian calculation of expected value. I think that constitutes a strong case as to why even minimally demanding sentiocentric antinatalists are responsible for the creation of fruit flies, and therefore all sentiocentric antinatalists are.

Related issues

There are many other examples of beings whose reproduction depends on our decisions. There is a greater cost linked to preventing their existence, but depending on how morally demanding the view we subscribe to is and what action a person is willing to take, that cost may be supererogatory or obligatory in theory or practice. Selected examples, with varying degrees of demandingness and expected value, may include preventing/not causing the existence of:

• Fungus gnats associated with houseplants, as well as other pests found on houseplants (aphids, mealybugs, spider mites, whiteflies, scale insects, thrips). It would be optimal to have no house plants at all, but caring for them and eliminating pests before they multiply may be suboptimal but more acceptable for many, perhaps especially when the plants increase psychological comfort (although the question remains whether the suffering of invertebrates is worth this convenience).
• Booklices and moths feeding on the storage of organic materials.
• Cockroaches, flies and other invertebrates thriving on discarded unprotected food scraps.
• Spiders breeding in untidy areas, and other invertebrates in there (in basements, attics, utility rooms)
• Mites multiplying on less frequently washed bedding.
• Parasites on captive animals (like pets).
• Small crustaceans, insect larvae, nematodes and other invertebrates developing in small bodies of water in gardens, such as ponds, birdbaths, or even rain-filled containers.
• Earthworms (e.g. Eisenia fetida and Lumbricus terrestris), red wigglers (a type of earthworm), potworms (Enchytraeidae), springtails (Collembola), various mites, beetles (such as rove beetles and ground beetles), various species of ants, flies (including fruit flies and soldier flies), sails and slugs, millipedes (Polydesmida), woodlice (Isopoda), centipedes (Chilopoda), and various other insect larvae, as well as other invertebrates multiplying in composters.
• And also all insects, springtails, arachnids, crustaceans, myriapods, annelids, nematodes, snails and slugs, other invertebrates, as well as small vertebrates that breed in gardens. It would be optimal to make the garden uninhabitable, for example by covering it with concrete, gravel, or otherwise depriving it of habitats for new creatures (see Tomaik below). It may be more acceptable for many to give up dense vegetation, avoid bodies of water in the garden, or cover part of the garden with something that prevents some creatures from breeding (such as gravel, tiles or concrete).

The examples presented above are characterized by varying degrees of demandingness, but I encourage all sentiocentric antinatalists to seriously think through those issues, and limit their influence on causing the creation of conscious beings, seriously weighing their own discomfort against the suffering of these invertebrates for whose existence we are relatively directly responsible.

Further reading

Brian Tomasik on not causing insect suffering:

How to Kill Bugs Humanely

Speculations on Invertebrate Population Dynamics Relevant to Reducing Suffering

Convert Grass Lawns to Gravel to Reduce Insect Suffering

How Many Springtails Are Created by a Gram of Grass?

How to Avoid Hurting Insects