Hunters without webs
Water Spiders (Family Pisauridae) wait for prey at the water's edge. Their front legs rest on the surface, sensing vibrations in the water. They can grab tadpoles or fish swimming past, or race across the water to seize insects that fall in. Photo: © Densey Clyne.
Thomisid dung spider, Phrynarachne decipiens
There are many other araneomorph spiders that no longer build snare webs. Such spiders also have a surprising range of prey catching strategies. Many are ambush hunters like the flower or crab spiders (Thomisidae). These spiders have quite good eyesight. They sit in the open, on foliage (Sidymella spp.), flowers (Diaea spp.) or bark (Stephanopis spp.). Their body colours usually merge well with their background (flower frequenting species are capable of adjusting their body colour to suit), concealing them from both predators and prey. Using sight, vibration and touch senses they target insects and other prey alighting or walking nearby - like flies, butterflies and bees, some of which may be considerably larger than the spider. Their strong, spiny front legs allow them to grasp and hold the prey while it is bitten. A tropical thomisid species, Phrynarachne decipiens, has gone about things a little differently. Its body colour and shape resembles a drop of bird dung. However, as well as looking like a 'turd' the spider also secretes a chemical scent that makes it smell like one! Flies and butterflies that feed on dung (yes, some butterflies do this) are attracted to these 'dung' spiders, which ambush and eat them.
Many other litter, bark and foliage hunting spiders use lie-in-wait ambush as well as active wandering strategies to catch their prey. These include groups like the ground spiders (Gnaphosidae), huntsman spiders (Sparassidae), sac spiders (Clubionidae) and sun spiders (Corinnidae). None of these groups have good vision and they depend more upon vibration and touch cues to sense and ambush any insects or other arthropods encountered - such senses are obvious attributes for night hunters (all except the corinnids). Water spiders (Pisauridae) hunt along stream and pond banks, their legs extended onto the water film sensing vibrations caused by fallen insects or small fish and tadpoles.
Some of these hunters, like white-tail spiders (Lamponidae) and assassin spiders (Mimetidae) are spider hunters that will readily invade the webs of other spiders. The remakable archaeid spiders are also spider hunters in leaf litter and moss. These small, bizarre looking spiders have extremely long, pointy heads and elongate, slender jaws. They use the long jaws and fangs to spear their spider prey.
Colourful Lynx Spiders (Oxyopes) hunt insects on shrubs and grasses. Photo: M Gray © Australian Museum.
Large eyed spiders like the wolf spiders (Lycosidae), jumping spiders (Salticidae) and lynx spiders(Oxyopidae), visually hunt and ambush prey in ground litter, on bark and and foliage. Probably the most remarkable of the visual hunters are the jumping spiders of the genus Portia. They use sight, disguise and a remarkable set of stalking strategies to capture spider prey, including other jumping spiders.
