Buzz
The challenge in compiling a list about spiders and their terrifying relatives is that many of you might end up shrieking and throwing shoes at your screen, rather than reading on. After all, these creepy, unsettling arachnids seem to exist with the sole purpose of eating your face. Yes, specifically your face, the person reading this right now. But if you can overlook that, you’ll find these tiny creatures display surprising intelligence and social behavior. Some, however, embody true horror, so you might want to keep your shoes within reach.
10. Males Consuming Females
Previously, we noted that females often eat males. This makes sense—the male sacrifices any future breeding opportunities, but in return, the female gets a substantial meal, boosting her chances of successfully carrying eggs. However, the spider Micaria sociabilis flips the script, with 20 percent of mating events resulting in the male eating the female. They aren’t the only species to exhibit this odd behavior, but there’s no clear reason for why it occurs.
Researchers in the Czech Republic sought to uncover an answer by observing which females end up being consumed. Micaria sociabilis produce two generations of offspring annually: one in spring and another in summer. When males were paired with females from both generations, they were significantly more likely to devour the older females, leaving the younger ones alone. This strategy of using older females as nourishment to enhance the chances of mating with younger females later seems effective, as younger females are more likely to reproduce successfully.
9. Matriphagy
Given the infamous reputation of the black widow, any spider with 'black' in its name is immediately regarded with suspicion. The black-lace weaver spider is no exception, having a rather disturbing method of entering the world. When its spiderlings hatch, the mother encourages them to consume her alive. After finishing her off, they take over her web and hunt in groups to catch prey up to 20 times their size. The young spiders also defend against predators by synchronizing their movements to make the web pulse.
Another spider that consumes its own mother is Stegodyphus lineatus. Its offspring spend a period feeding on regurgitated fluid from their mother. Eventually, they liquefy her insides and drink them—all with her full cooperation.
8. Family Dynamics
Common names for arachnids can often be misleading. The whip spider, also referred to as the tailless whip scorpion, is neither a true spider nor a scorpion. It belongs to an entirely different arachnid order called Amblypygi. These eight-legged creatures resemble a mix between a spider and a scorpion but are equipped with whips. If that comparison doesn’t sound endearing, let us also introduce Florida’s Phrynus marginemaculatus and Tanzania’s Damon diadema.
Researchers at Cornell discovered that these whip spider species prefer to live in family groups. When separated, siblings and their mother regrouped. The families become aggressive toward outsiders and spend their time constantly grooming and touching one another. Scientists believe that sticking together might help these amblypygids ward off predators while allowing mothers to protect their young.
7. Fatherly Involvement
What do spider fathers bring to the table for their offspring? While some simply offer their bodies to the female as a convenient snack—taking the easy way out—tropical harvestman dads are far more hands-on. They step up to guard a nest of eggs once the female has laid them. Without the males keeping watch, the eggs fail to survive. These fathers fend off ants, maintain the nest, and remove any fungus, sometimes for months.
This strategy offers several benefits for the males. For one, it earns them some serious admiration from the females. Males are capable of caring for the eggs of up to 15 mates at once. Research also shows that these dedicated father spiders tend to survive at higher rates than their more negligent counterparts. This is likely because sticking around in one place keeps them out of reach from predators that might otherwise feast on them, especially since the females help by leaving a protective mucus around the nest.
6. Task Allocation Based on Personality
Continuing our exploration of the genus Stegodyphus, let's meet Stegodyphus sarasinorum. These spiders, like their relatives, liquefy and consume their mother’s insides. However, they also stand out for their unique behavior of living in colonies where tasks are divided based on personality traits. Researchers studied the aggression and boldness of these spiders by gently provoking them with wafts of air and poking them with sticks. They marked each spider with different colored patterns to track their movements as they built their colony.
Next, the team wanted to observe which spiders would be the first to investigate struggling insects trapped in their webs. The spiders respond to the vibrations created when insects squirm. Rather than shaking the entire colony by hand, which would introduce too many variables, the researchers used an electronic device that created consistent vibrations: a small, pink tool called Minivibe Bubbles. We’ll leave it to you to guess its original purpose.
The scientists discovered that the spiders who immediately darted to capture prey were the ones that had demonstrated the most aggressive personalities earlier. This behavior seems logical, and this kind of task specialization is as beneficial for spider colonies as it is for human societies.
5. Courting in the Perfect Manner
Male wolf spiders invest considerable effort into making a strong first impression on potential mates. Much like humans, their success hinges on effective communication. Several studies have demonstrated how male wolf spiders adapt their signaling methods to maximize their chances of attracting a mate.
Researchers from the University of Cincinnati placed male wolf spiders in different environments—rocks, soil, wood, and leaves—and discovered that their signaling vibrations were most successful in a leafy setting. In a follow-up experiment, the spiders were given a choice of surfaces and spent more time signaling on the leaves compared to other materials. On less optimal surfaces, the spiders also reduced their reliance on vibrations and resorted to visual displays, such as raising their legs.
Adapting communication techniques isn’t the only strategy a wolf spider has up its sleeve. Scientists at Ohio State University observed that wild male spiders seemed to mimic their rivals in an effort to improve their chances of mating. To test this, the researchers showed wild males a video of another male engaged in a mating ritual. The test subjects promptly mimicked the behavior. This ability to eavesdrop and adjust their actions is a sophisticated behavior rarely observed in small invertebrates.
4. Cross-Species Communities
Social spiders that live in colonies are uncommon. However, scientists have discovered a colony made up of two distinct species cohabiting together. Both spiders belong to the genus Chikunia, which makes them as related to one another as wolves are to coyotes or modern humans are to Homo erectus. Lena Grinsted, a researcher from Denmark, unearthed this unusual coexistence while conducting experiments to determine if female spiders would reliably protect the broods of other females.
It soon became apparent that the colony contained two different species of spiders. This discovery was confirmed through genetic analysis, which revealed distinct differences in their genital structures. It’s unclear what benefit the two species derive from living together, as neither brings any noticeable advantages to the arrangement. They don’t hunt in tandem, nor can they interbreed. The sole benefit seems to be shared childcare, with females content to watch over the offspring of both species.
3. The Blood-Feeding Spider That Loves Stinky Socks
Evarcha culicivora, also known as the vampire spider, is quite a peculiar creature. Its name might suggest it glimmers in the sunlight, but that’s not the reason—it actually comes from the fact that it feeds on human blood. However, instead of directly attacking humans, this spider consumes mosquitoes that have recently bitten a human. The vampire spider is the only known animal that selects its prey based on what its target has recently ingested.
Once the spider detects the scent of blood, it becomes frenzied, hunting and killing up to 20 mosquitoes at a time. This behavior may actually be beneficial, as the mosquitoes it preys on, Anopheles gambiae, are known to carry malaria. By helping control mosquito numbers, the vampire spider contributes to saving human lives.
Because its food source is often found near humans, the spider also resides in human-inhabited areas. It is particularly drawn to the smell of human settlements, including the scent of dirty socks. In one experiment, vampire spiders were placed in a box with either a clean or dirty sock. The spiders stayed longer with the used sock. Researchers hope this finding might aid in attracting spiders to help manage mosquito populations.
2. Gifts And Deception
When a male nursery web spider spots a female he wishes to mate with, he attempts to impress her by offering a gift. This typically takes the form of a dead insect, showcasing his hunting prowess and, by extension, his strong genetic traits. The spiders even go so far as to wrap their gifts, though they miss the chance to add a charming little spider-silk bow. Statistically, males who don’t present a gift are given only about 10 percent of the mating time compared to their more generous rivals.
Occasionally, a male spider may struggle to find a suitable fly, or he may be so tempted by its taste that he consumes it before presenting it to his mate. In such cases, he’ll wrap up the empty carcass of the insect or any similarly sized scrap he finds nearby. While this trick works to some degree—spiders offering fake gifts still get more time than those who bring nothing—it’s only temporary, as females soon detect the deception and allocate less time for sperm deposition than they do to males who bring real food.
1. Selective Aggression
Most arachnids in colonies tend to hunt as a group. However, the colonial orb-web spider is an exception—it lives in a colony but hunts solo. During the day, hundreds of spiders relax in a shared web suspended between trees and bushes by numerous threads. As night falls and hunting time arrives, each spider constructs its own orb web on the long threads to capture insects.
Once a spider has chosen its location and constructed its web, it doesn’t want any other spiders moving in. If a fellow colony member approaches, the builder reacts by bouncing on its web to drive the intruder away. Typically, the unwanted visitor takes the hint and looks for a new spot, but this changes when all the prime locations have already been occupied.
With no empty spots left, orb-weaving spiders without a web will disregard the web builder’s warning bounce and remain near one of the existing webs. The builder doesn’t attack, and the interloper usually manages to steal a meal from the hard work of the other spider. However, no confrontation occurs, as the bounce is more of a polite reminder: ‘Have you explored all your other options?’
