Spider behavior
[2][3][4] Spiders' guts are too narrow to take solids, and they liquidize their food by flooding it with digestive enzymes and grinding it with the bases of their pedipalps, as they do not have true jaws.
[5][6][7] However, most of these spiders still need a mostly carnivorous diet to survive, and lab studies have shown that they become unhealthy when fed only plants.
[6] One exception is a species of jumping spider called Bagheera kiplingi, which is largely herbivorous, feeding mainly on the sugar rich Beltian bodies produced by acacia plants.
[10][11] Female water spiders (Argyroneta aquatica) build underwater "diving bell" webs which they fill with air and use for digesting prey, molting, mating and raising offspring.
The Australian crab spider (Thomisus spectabilis) manipulates UV signals to attract bees to flowers in which they are hiding.
Some Conothele species do not build a burrow, but construct a silken tube with trapdoor in bark crevices.
Females of Segestria florentina sometimes die while guarding her eggs and the hatched spiders later eat her.
Non-reproductive cannibalism: Some spiders, such as Pholcus phalangioides, will prey on their own kind when food is scarce.
In the nursery web spider, the male sometimes feigns death to avoid getting eaten by females during mating.
Many of these social spiders show cooperative brood care, use the same nest (web), and have some amount of generational overlap.
Some biologists argue that this classifies these species as fully eusocial as these non-reproductives can be considered a non-sterile worker caste.
[23] Although all arthropods use muscles attached to the inside of the exoskeleton to flex their limbs, spiders and a few other groups still use hydraulic pressure to extend them.
After that, it starts releasing several silk threads from its abdomen into the air, which automatically form a triangular shaped parachute.
Under experimental conditions, when spiders were injected in the leg with bee or wasp venom, they shed this appendage.
But if they are injected with only saline, they rarely autotomize the leg, indicating it is not the physical insult or the ingress of fluid per se that causes autotomy.
