Unlike black widow bites, brown recluse bites aren’t painful immediately. But the venom from a brown recluse spider can cause serious skin problems around the area of the bite, which typically become increasingly painful in the hours after the bite.

Black widow spider bites

What they look like:

When a black widow spider bites, it typically causes a painful pinprick sensation. The site of the bite then swells slightly and forms a red rash. You might see two fang marks inside the bite area or a mark that looks like a tiny sting.

Other symptoms:

Black widow spider bites are usually painful immediately. It can also cause swelling, redness, pain and numbness or tingling radiating out from the bite, MedlinePlus says.

And, unlike, brown recluse bites, a black widow spider bite can cause symptoms that affect a large area or the entire body.

When black widows bite, they release a neurotoxin into your body which can cause symptoms such as pain throughout the body, nausea and fever. The symptoms typically begin to worsen within 15 minutes of the bite.

Wolf spider bites

What they look like:

Larger spider species, like wolf spiders, can be a little more aggressive and may bite people occasionally, Gangloff-Kaufmann said. But these bites are typically not dangerous because these spiders are not venomous.

These bites look like raised red bumps.

Other symptoms:

Aside from the bump, you may experience some initial pain at the site of the bite, followed by itchiness for a few days.

Mosquito bites

What they look like:

Mosquitoes leave itchy bumps on the skin that may swell and become red. These reactions typically appear within minutes after a bite, the Mayo Clinic says. In some people, the reaction may look like a painful hive or a blister that forms within 24 hours of the bite.

The bites don’t tend to appear in clusters but rather as individual bumps, possibly on different parts of uncovered skin. Some people have more severe reactions that cause a hive-like rash in the area around the bites.

Other symptoms:

Mosquito bites don’t typically cause symptoms beyond the annoying, itchy bumps. A severe allergic reaction may come with a hive-like rash, swelling and inflammation of the bite area and swelling around the eyes, the Mayo Clinic says.

Bee and wasp stings

What they look like:

“Bees and wasps are stinging you as a defense,” Frye says. “You almost instantly know when you’ve been stung by one of them because they want you to know right away.”

Along with the pain, you will likely notice a raised welt pretty immediately, Kassouf says. You might even see a stinger or pinprick mark inside the bump. Some insects, like wasps, will both bite to hold themselves in place and sting you, Frye says.

People who tend to be more reactive may have severe swelling in the entire limb, and “you can get blisters on top because it’s so swollen,” Kassouf says.

Other symptoms:

Depending on the exact insect that stung you and how reactive you are to the sting, you may have itching, swelling and pain at the site which tends to be worse in the first few days and then gradually go away, Kassouf says.

Ant bites

What they look like:

When ants bite humans, it grabs the skin and also sprays a compound called formic acid, Frye explains. Ant bites tend to be small, swollen bumps that appear in clusters, Kassouf says.

Fire ants also sting humans, Frye says, which can cause small pus-filled bumps on the skin, according to the Cleveland Clinic.

Other symptoms:

Ant bites are typically painful and itchy. In addition to the bites, fire ants use their stinger to inject a venom called solenopsin, which causes a burning sensation, Frye says.

Lice bites

What they look like:

Lice bites are often easier to identify than other critters on this list because you’ll likely see the live lice in hair, Frye says. While head lice and body lice are closely related subspecies, pubic lice are a separate species, he explains.

“They’re attached to the hair follicle,” Kassouf explains. “They will come down to the skin to feed and bite and then go back.” At first, you might just have a few. But as they multiply, you may start to notice the small itchy bites on your scalp or other skin areas, she says.

Other symptoms:

In addition to the lice and their bites, you might notice lice eggs called nits, Kassouf says. Nits are tiny, hard and white, and they stick to the hair follicle.

Body lice can also transmit pathogens, Frye says, which is particularly a problem for people who have poor hygiene, such as homeless populations.

Fly bites

What they look like:

It’s not that unusual for flies to bite humans because the female flies need to feed on blood to have the energy to produce eggs, Frye explains. And fly bites may look and feel different depending on the particular species of fly that’s biting you, he says.

For example, tiny biting midges may cause very small bites with temporary symptoms that last just a few minutes, he explains. On the other end of the spectrum, horse flies and deer flies use “blade-like” mouthparts to slash the skin before eating the spilling blood, which causes large, painful bites, Frye says.

A fly bite typically looks like a red welt, and “it often has a little center core to it,” Kassouf says. “It can look a lot like a bad mosquito bite.”

Other symptoms:

Again, the other symptoms you might experience depend on the type of fly that bit you.

For instance, if someone is constantly exposed to black flies, for instance, they might experience headaches, fever, swollen lymph nodes and other symptoms of so-called “black fly fever,” Frye says.