Question

I used to think the reason we see a lot of dead bugs wrapped and hanging on spider webs was that they get caught by spiders and after the spiders are done with the bugs they leave them there. But I have had a few spiders trapped in a plastic bottle and that assumption no longer seems correct. I haven't found any articles online that sufficiently address this.

I notice that the spiders in the bottle actually actively work to make web to hang up dead bodies, even if the bodies are much larger than them in size and are not their prey. For instance, there was a pretty sizeable spider in the bottle when I trapped a few newcomers. The large spider had been dead in there for weeks. I was just too lazy to get its body out. The newcomer spiders were much smaller but they soon worked to wrap up the dead body of the large spider and hoist it so it didn't stay at the bottom. The same also happened with the body of a moth several times their size. House spiders in general don't attack other bugs that outsize them or even their own size because they only attack bugs they can pin down. So the moth died of natural causes in the bottle-starvation I assume, but its body was also hoisted. Why do they do that?

Answer 1

Spiders spin webs for catching prey and other purposes, and may wrap dead insects in a confined space to prevent decay or manage their environment. Their behavior also contributes to ecological balance and may be an instinctual response to potential prey items.

Step-by-step explanation:

Spider Behavior Regarding Web Building and Dead Insects

Spiders spin webs as a behavioral adaptation for various purposes, including catching prey, climbing, producing egg sacs, and wrapping prey. This behavior is a staple of animal behavior in response to their ecological roles. When spiders in a confined space, such as a bottle, encounter dead insects, they may wrap and hoist these items to keep their living areas clean or to prevent the decay from attracting potential predators or competitors. Although they are primarily carnivorous, feeding on insects and other small animals, they are not known for disposing of the dead simply for cleanliness. However, it's possible that this behavior is a form of environmental management or it could be instinctual behavior to wrap anything they come in contact with that resembles their typical prey, regardless of whether it poses a food opportunity.

Flies and maggots are known to seek out dead animals for laying eggs, indicating that the presence of dead bodies could affect the local mini-ecosystem within the confinement. By wrapping and moving these dead insects, spiders might be attempting to manage their space to minimize the risks posed by the decay process and other scavengers. This behavior can be related to maintaining an ecological balance in their immediate environment. It's also worth noting that spiders lack certain sensory organs like antennae, but are equipped with chelicerae and pedipalps for feeding and manipulating their environment.