Fiddler crab a vital role in the preservation of wetland environments; by sifting through the sands, they aerate the substrate and prevent anaerobic conditions. Fiddler crabs live rather brief lives of no more than two years (up to three years in captivity). Male fiddler crabs use the major claw to perform a waving display as a form of female courtship. Females choose their mate based on claw size and also quality of the waving display. In many fiddler crab species, the female occupies the burrow of their mate while she lays her clutch of eggs. Research shows that the male major claw
Nephilengys upon by the spider-eating jumping spider "Portia". At least some species shake their bodies vigorously when touched. Nephilengys Nephilengys is a genus of tropical spiders of the family Araneidae, consisting of two currently described species. (The genus was formerly placed in the Nephilidae and Tetragnathidae.) The genus "Nephilingis" has been split off from this genus. Both genera have been called hermit spiders from the habit staying in their retreats during the day; the name eunuch spiders has been used for "Nephilengys" alone. Males may sever parts of their palpal bulbs after copulation. Females are from 10 mm to 28 mm