If you are referring to Black Widow Spiders that can be found on banana stalks; they can bite you and inject a toxic poison.
That's the way they scare you so you will not come near them or hurt them
Banana spiders are arachnids.
brown
Banana spiders andcamel spiders
Banana spiders and African "Wasp" Moths
Yes
Yes
brown
yes
birds
Banana spiders have an egg sac and can have up to 2000 eggs in their egg sack
At least three different kinds of spiders get called "banana spider". The yellow and black Argiope genus spiders (and other spiders in that genus) are called banana spiders. The second kind of "banana spider" is the Golden-silk orb weavers are tropical and subtropical spiders, so maybe there is some real association with banana trees occasionally. The third kind of "banana spider" is the very dangerous Brazilian wandering spider. The first two kinds of spiders have venom that is no real problem for human beings. The Brazilian wandering spiders have a strong venom.