Yes, for many, it’s a very common outcome of physically interacting with them in any but the gentlest and most passive ways. It depends on the senses and nature of the bug, what it can notice, and what it’ll think of it.

Flies very frequently start evading if you even move things toward them.

Even gently bumping into most crawling bugs will tend to cause them to either evasively scurry away, run for someplace safe (such as a crack), or for some types, curl up or take other defensive postures.

Some will also attack, which is generally a type of defensive fear behavior in most cases.

We have small jumping spiders around here. Even though I’m ~million times its size I find it creepy when they rotate their bodies and track me as I walk past them. They will hop away if I get too close.

No. They don’t have the brainpower or advanced intellect to be ‘scared’ in any sense of the word.

When the insects jump or flit or whatever, it is purely an instinctive physical response to stimuli that the millions of insect generations of evolution created.

A mosquito does not think to itself “oh my, the flyswatter is coming to get me – I’m petrified”.

I suppose it must be a matter of your point of view. You can certainly provoke most bugs to react in ways that you would associate with fright in a person. It sets you to thinking. Is it possible to intimidate a bug? I figure it’s about semantics, and the easy way out is to qualify fright as an instinct. With that contrivance— the answer is yes.

Are cicadas bugs? We’re about to be inundated. Don’t think we can scare them.

@elbanditoroso “No. They don’t have the brainpower or advanced intellect to be ‘scared’ in any sense of the word.”
– Having studied and bothered, attacked and terrorized thousands of insects, that seems very incorrect to say. They have various states that to me seem best described by words such as calm, curiosity, alert, and various levels of panic and fear.

Doesn’t a fear response entail some sort of foresight, anticipation of an event or action or consequence? Are insects capable of that? If it’s purely an instinctive fight-or-flight response, is that actual fear? Even in humans that often seems mindless.

I know we can’t verify the subjective mental state of an insect, but researchers have found ways to recognize inner states of nonverbal entities. And observed insect and arachnid behavior does seem consistent with some things we know about ourselves, such as curiosity.

I’m going to say yes. In fact our freeze reaction when frightened is observed in some insects. The deer in the headlights type of response. I had this response when I was mugged (I wasn’t harmed) and I had no idea I would freeze like that. Fight or flight is often talked about, but freeze is a reaction often left out of conversations that is very real.

You can scare a fly. If you want to swat one, aim two inches behind.

I’m making a distinction between startling and actually frightening. Is the fly afraid or just reacting instinctively? Does it experience anything like fear, or is it just a reflex? Are they the same thing?

@Jeruba Yes, insects are definitely capable of “some sort of foresight, anticipation of an event or action or consequence”. They act with purpose and organization, and shift behavior depending on the situation.

Reflexes are different from states of fear. Reflexes are like when you hear a loud sudden noise and jump immediately. Fear is when you feel an emotion and respond to it (e.g. fight or flight) until the situation changes and you calm down. Different bugs relate to the world differently and may be scared by different things, but some bugs with good enough distance vision can sometimes figure out that there is a human creature threatening them (for some, you don’t even need to go near them before they evade and run for cover.

Spiders (though not technically insects) in particular I’ve noticed sneaking around but then when they notice I’m around they’ve hurried for a place to hide, and some have even eluded my pursuit by trying to fake me out by running around a corner and then immediately changing direction or doubling back as I try to follow their previous direction.

That’s a very satisfying answer, @Zaku. Thank you.

I do understand the difference between reflexes and emotional states in human experience. I was asking if there’s any difference for insects and arachnids, or if we’re just anthropomorphizing. It seems there is. When I echoed your mention of curiosity, I was thinking of spiders in particular, who often seem to drop down from somewhere just to see what’s going on.

Do you think that when they run for cover they know they’re hidden because they can’t see the threat any more, or because the light has changed (they’re in shadow), or something else?

15 years ago I got out of the shower and a huge spider with a death wish chased after me. The table’s turned when I found one of my size 15 running shoes. Splat city.

Spiders can feel emotions. Like mine that had an obvious death wish

Bugs might always be living in fear. An evolutionary advancement. Like a permanent mental illness.

@Jeruba I think that with each species, their senses, experience of locations and situations, and the ways they relate to those, are all different, but I think it is clear that spiders and insects do all have some kind of understanding of space, terrain, and situations, and they have different states and different intentions at different times, and that definitely includes the ability to use their senses to try to understand their environment, and then make choices based on that information to respond to that situation to serve their needs.

When I was a kid, I used to spend hours and hours putting insects (mostly ants) in (very often rather inhumane) different perilous situations and carefully watching what they did. They have a very strong ability to discover and explore their new situation, and respond appropriately.

Ants can react to shadows, and are more likely to if they’ve recently been alerted that something may be stalking them. Almost all insects seem to have varying levels of alertness and perception of danger that an animal is after them, even if they don’t see very well. Wasps have a better visual command of space, and different escalation levels of their attacks to drive animals away from their nests and food.

I think with the especially evasive spiders, they can definitely see me at a distance and have a good understanding both of the building layout within at least 20 feet, and also show the fairly advanced tactic of running to get out of sight and then going a different direction and waiting, and then moving quickly again if the animal comes back into sight. I think it is vision-based, but these ones are definitely aware of where they can go to find hiding places and escape into walls or behind/under furniture. And they rush to hide as soon as they see a human (though mainly if humans move, not if you’re sitting motionless). But most spiders don’t do anything like that and seem to mostly ignore humans unless you touch them or come very close, or touch their webs.

I’m starting to think insects are in a constant state of anxiety.

Insects sleep less, I think some don’t sleep at all? Some sleep, but don’t go through REM. Some do exhibit cognitive impairment from lack of sleep. We typically see longer sleep needs in animals that are higher in the animal kingdom hierarchy.

Lions can sleep 20 hours a day, but they have less concerns about becoming prey. When we sleep we are more vulnerable. This implies many insects are in a constant state of vulnerability.

I think it’s really hard to distinguish between instinct and actual fear. Certainly, being fearful is partly instinctual, but maybe not the other way around. Part of fear is learned also, but some insects don’t really get instructions from parents or peers, so those types of bugs are working off of pure instinct I guess, and maybe don’t experience any sort of fear, which contradicts my first statement in this answer.

Good question.

The reason I am prone to think fright a matter of instinct is that it is so obviously useful as a matter of self preservation—a survival trait. Those lacking it are slated for ready extinction. Fear, on the other hand suggests drifting toward the requirement of reflection, and anxiety is so certainly associated with thinking that it links with that great and exclusive human refinement—neurosis.