This page summarizes the tendency of spiders to form colonies and to live in integrated societies rather than in a solitary fashion.
In general, spiders are solitary creatures but, as outlined in the following paragraphs, there are circumstances in which they do appear to exhibit some form of social interaction.
What kinds of social/communal behaviour do spiders exhibit?
The following are listed in order from the most frequently seen to the relatively uncommon:
Adult males of the majority of spider species must approach their female counterparts with considerable caution and will normally do this only when the instinct to mate is irresistable. Present evidence indicates that for both sexes this instinct is affected by environmental conditions. In particular, males often need to receive the appropriate temperature and humidity stimuli before carrying out their maturation moult and commencing the search for a female. Similarly, environmental conditions such as the availability of a good food supply seem to play a major role indetermining when the females will produce eggs and how many they will lay in each batch.
The female rarely, if ever, seeks out the male but will sometimes tolerate his continued presence nearby provided he avoids making
provocative movements. She is normally well aware of his presence, perhaps because of vibrations transmitted through her web (assuming she
has one), although the males of species such as Arachnura
higginsi are much smaller than the females and appear to go almost unnoticed. For some species there may even be several males lurking
nearby, all hoping to be able to make a successful approach. Males of Deliochus zelivira
even manage to survive indefinitely in close proximity to a female, perhaps because she is usually in her retreat and the male is
shielded by leaf fragments and webbing.
For a typical spider species the actual mating is preceded by an elaborate courtship ritual in which the male shows great enthusiasm and the female
appears aggressive or indifferent. It is probably most common for a male to approach a female from behind and/or from underneath in order to stay out of her field of vision. The eventual coupling is usually abdomen to abdomen, though the two sexes may be facing in opposite directions,
but sometimes the male positions himself on one side of the female. For mygalomorphs such as the funnel-web species,
Hadronyche infensa, the approach is front-on and the male makes use of structures such as leg spurs
to restrain the female from attacking during sperm transfer. Once mating has occurred the male of some species may escape to repeat the process, not
necessarily with the same female, or may do little to avoid being eaten by his mate. This is particularly true for those species for which the
males die soon after maturing even if they have never managed to find a female to mate with.
Fortunately, these spiders then try to escape rather
than attack the person who destroyed their temporary home.
A different form of maternal care is practised by wolf spiders such as Lycosa godeffroyi.
Lycosid females typically drag their egg sacs around behind them when they wander above ground and then subsequently
piggyback the newly hatched spiderlings on their upper surfaces. Presumably, this latter
practice also allows efficient dispersal of the young spiders.
However, the non-territorial
interaction that occurs in this comunal nest only involves immature specimens and each spider (apart from the original adult female) leaves the colony before maturing.
Some authors have suggested that small theridiids such as Argyrodes species display a better example of mutualism.
These theridiids don't need to make their own webs because they spend most of their time on the edges of araneid webs and may serve to keep the orb-weaver's web tidy while feeding on trapped insects that are too small to attract the attention
of the araneid itself. Realistically, this may not be true social behaviour either in that the araneid is probably not even aware of the smaller spider's existence and is actually being deprived of a portion of its food source.
Email Ron Atkinson for more information. Last updated 30 December 2009.