What evolutionary function does annoyance serve?

Self preservation.

Perhaps it’s the salt in your sweat that the fly craves to the point of tempting certain death.

I agree self preservation. Whether it be from a fly or a possible future mate. If you are annoyed it might be good to steer clear.

It’s a parasite trying to get the fruits of your labor: your salty sweat. If there was a piece of cake around it would doggedly go after that. But at that moment, you are the best deal around. After two ineffective swings of your arm, it figures you are too slow to be a threat so it keeps coming back for more until you capitulate and it is fully satisfied, or you kill it.
Wait for it to land and shoot it with a rubber band. Let’s see them evolve past that!

Annoyance builds up your alert level. Makes you more aware of your surroundings.

Anthropologically, it is like little ‘antennas’ that tell you, on a very basic level, that danger is near. This is all about self-protection.

“Annoyance” might be considered “persistence” in the fly’s opinion.

One advantage of the fly’s behavior is that your smelly body reminds it of of a rotting corps and thus a food source. Also there slight chance if it annoys you enough you fall off the ladder and die. Then the fly can lay it’s eggs on your decaying body.

@gondwanalon You mention a rare event but you know it has to have happened. And one good corpse can feed a lot of maggots.

Yep, self preservation and attraction to a potential food/ maggot raising environment.
Get one of those awesome electric fly swatters, we have one here, they are very rewarding and allow you to indulge in your hidden sadistic side. ZZZZZZap!
Or, hang a fly strip over your head. lol

I find that I get annoyed when people look for evolutionary reasons for things that don’t seem to me to call for evolutionary thinking. My hope is that this annoyance will eventually help us evolve beyond that level of thinking.

As human beings we are driven to seek pleasure while avoiding pain or any sort of discomfort. This goes back to our earliest days of evolution. (What would you rather have, a fresh juicy apple or a sharp stick in your eye?)

While the fly buzzing around doesn’t necessarily hurt you, its presence is undesirable and the fact that it can’t be easily dealt with is well…annoying.

I don’t think that annoyance has a specific evolutionary explanation. Instead, it is better explained as a consequence of a broader adaptation (namely, emotional experience). Evolution takes the path of least resistance, so we’re more likely to develop a general capacity for feeling emotions than an optimized set of specific emotions unless certain emotions turn out to be so destructive that they prevent large numbers of humans from reproducing.

So why would emotions develop? Again, the path of least resistance. We know that emotions developed prior to intellect. One reason for this could be that intellect is resource intensive and very complicated to coordinate (on the biological level as well as the psychological level). And some neuroscientists believe that emotion is actually necessary for intellect, so it would have had to develop first.

Second, hardwiring the most basic survival instincts rather than leaving them to intellectual investigation increases the chances they will be followed. Emotion is directly tied into our decision-making pathways, whereas intellect has to take a more roundabout path (so roundabout that some people doubt it’s actually involved at all, though I think that interpretation rests on a mistake). So emotions make us act in certain ways both quicker are more reliably. Seems like a good idea when it comes to the basic stuff that keeps us alive. But sometimes it slips out into the other parts of our lives (for better or worse).

You’re misusing the word. “Annoyance” is a subjective feeling that resides only in the mind/s of the one/s experiencing an “annoying” event. In other words, the fly is “an annoyance” to you; it’s not annoying by itself.

So the question of evolutionary advantage to the fly in “being annoying” is entirely misplaced. The fly evolved to live in a particular niche of various biosystems, including at least one in which you would prefer to live fly-free. So you are the one experiencing the fly’s “annoyingness”, if we can coin that word to mean “the state of being an annoyance”. Since we share a general antipathy for the species and its annoying behaviors: rapid flight into our personal space (or our food), the buzzing sound that announces their presence, their appearance, which we have learned to identify as “ugly”, since we don’t like the things that they do or the garbage that they seem to thrive upon, then we feel annoyance when we experience those things. The fly by itself is not “an annoyance”, it takes another being to be annoyed by the fly and to experience the feeling or emotion of “annoyance”.

Presumably, given a few million years of close proximity between flies and annoyed humans, fly species may evolve (there’s certainly no guarantee) which fly more nearly silently, or who avoid humans per se, though they will probably always be attracted to human environments, and perhaps which aren’t so repulsively and instantly ugly to us. In other words, one supposes, they will evolve into ladybugs.

Flies being annoying is IMO natures way of keeping the fly population in check. If they were not annoying we would have nice non-bothersome flies keeping their distance and multiplying like crazy. Since they are annoying like the one fly minutes ago who made the mistake of flying around my laptop and landing one too many times…the world now has one less fly to worry about.

Not every behaviour has an “evolutionary function”. Not all behaviours are derived from natural selection. Sometimes they are learned, or they just tag along genetically with other traits that are evolutionary adaptations.

@dappled_leaves I would respectfully disagree and Darwin’s law of survival of the fittest rules the roost and Lemurs that “tag along” end up going over the cliff.

I guess it’s important to consider the fly’s perspective. Your feeling annoyed is not its goal, it is simply a side effect of a fly’s search for food…and while ladybugs search the plant world for food, flies live in close contact with humans. Our worlds clash.

@Cruiser @dappled_leaves is a biologist, so probably one of the people best-suited to answer this question.

@Cruiser Survival of the fittest is compatible with evolutionary tagalongs. Vestigial organs might be a good example here. They no longer serve any function, and have largely withered into non-functionality over time. But we still have them because there is no evolutionary pressure to weed them out. Having them doesn’t hurt our chances at reproduction, and not having them doesn’t help our chances. So they limp along while other features determine the course of evolution.

Even certain features that are harmful may stick around if they come along with features that greatly increase our fitness (especially if, for some reason, you can’t get the good without the bad). If the ability to feel negative emotions is an inescapable consequence of having advanced minds, then the advantages of having an advanced mind will bring the ability to feel negative emotions along for the ride.

@JeSuisRickSpringfield So they limp along while other features determine the course of evolution. Reverse the order of your two points here and I am on board with you. Another comment I have to make is that it is easy to make statements about things like “vestigial organs” as being purportedly serving no function based on what information is available…I will offer that once upon a time, people believed the world was flat

@Cruiser “Reverse the order of your two points here and I am on board with you.”

I’m not sure I understand what you mean. Are you trying to say that neutral features (those that neither help nor hurt our chances at reproduction) determine the course of evolution while all the others limp along? That seems absurd, and would directly contradict your previous affirmation of the survival of the fittest. As for your link, at best it just tells us that the appendix isn’t a vestigial organ. It does nothing to disprove the larger point about vestigial organs in general (such as a vestigial tail).

Also, keep in mind that the point about features that neither help nor hurt our chances at reproduction is not meant to make eternal judgments about any feature. Something that neither helps nor hurts now could change as the environment changes. “Fitness,” after all, is not about the absolute goodness or badness of any given feature. It is about the relationship between an organism (or a feature of an organism) and the environment in which that organism lives. Gills are useless in the desert, and lungs are useless at the bottom of the ocean. So fitness is relative to a large degree.

And by the way, it has never in recorded history been the predominant view that the world is flat. That is a pervasive myth.

@JeSuisRickSpringfield I agree with your recent comment, except that “fitness” in an evolutionary context is not about how well an organism “fits” its environment, any more than it is about how “fit” an organism is in terms of strength or health. In an evolutionary context, fitness is only about how well it can reproduce. It’s a measure of how well it can pass its genes on to future generations.

It may be that this is what you meant, but your statement about fitness seems a bit ambiguous on this point.

@dappled_leaves In all the literature I’ve read on the subject, “fitting the environment” is just another way of talking about how an organism’s features affect its ability to reproduce (which, necessarily, varies from environment to environment since the same feature can affect the ability to reproduce differently in different environments). “Environment” is also used broadly in this context to mean something like “totality of circumstances” (and not merely as a way of describing the terrain or the weather).

@JeSuisRickSpringfield I sort of get what you’re saying… the thing about it that makes me uncomfortable is that the phrase “fitting the environment” implies that all of its traits are in some kind of perfect state to suit its current situation. But, of course, not all traits are being acted on by selection at any given moment (some perhaps never), and those which are adaptations were acted on by past environments. And yes, the current environment plays a role in the organism’s future fitness, but the phrasing makes it sound a little too… planned or designed?

So, broadly I agree with you. But I’ve learned to be a bit cautious about how I word anything to do with selection/adaptation/evolution for obvious reasons. Otherwise, there’s inevitably some kind of lame “gotcha” moment.

@dappled_leaves I know from reading about experiments with drosophila that a rapid and prolific reproductive cycle exponentially increases the rate of speciation when environmental pressure is present. Seeing the way cows and horses use their tails, elephants use their ears, and humans use their arms to swish away and attempt to kill flies, it’s clear that at least among mammals, flies are annoying. How annoying does fly behaviour have to become before flies with mutations to make their behaviour less annoying begin outbreeding the more annoying ones?

It’s entirely possible to live in close proximity to an animal and even to parasitize it without annoying it or even alerting it to your presence. The fly has seemingly chosen a set of behaviours specifically designed evolved to irk the creatures around which is exists. Which, all things being equal, seems like a pretty stupid adaptation.

Now you’re misusing evolution itself …

Most species don’t consciously choose the pro-survival behaviors that lead to speciation and continued evolutionary success. (We may be an exception to that general rule, and in fact we may be consciously choosing anti-survival behaviors species-wide. It’s pretty obvious that we often do that on an individual basis.) So flies didn’t choose to be “annoying”, but enough individual flies adapted in ways which we now find annoying (because we don’t like flies) that made the species move in that direction. “Annoyingness” may be an unintended consequence of the attributes of flight (particularly of that, since that’s what produces the buzzing noise that we tend to find annoying) which enable the species’ continued success.

In fact, the buzzing itself may be a particular pro-survival trait that we simply don’t get yet. It could be that a buzzing swarm of flies – indicating plentiful supplies of rotting food that signal a great place to lay the next generation’s eggs – may attract far more flies to that food source than are lost to even very many swatting human hands. (I discount entirely the notion that cow and horse tails are going to kill many flies that land on those animals.) And we have probably all seen videos by now of people who live among such huge quantities of flies – and have so little energy to spare, besides – that they simply accept the swarms and annoyances that we would find intolerable, given our far more sheltered lives.

And I wasn’t being entirely tongue-in-cheek when I suggested that in order to survive with humans (at least those of us who are annoyed enough and energetic enough to frequently take action against them) over a longer – much longer – evolutionary period, it may be that more and more silent fly species develop. (I think the same of mosquitoes; if quieter mosquito species develop then they may crowd out the ones that annoy us with their whine in flight, as they would be the ones more likely to survive in a dark bedroom, for example, and to survive multiple feedings on unsuspecting hosts.)

The sheer number of flies in the world is basically unaffected by the number of deaths by swatting. We’re talking about a creature that is so prolific that its offspring can appear on corpses before they’re cold. The, what, 50? 100? flies you’ve personally squashed isn’t enough to make a dent in the course of natural selection.