Web_types Spider

1 web types

1.1 orb webs
1.2 tangleweb spiders (cobweb spiders)
1.3 other types of webs

web types

the large orb web of araneus diadematus (european garden spider).

there no consistent relationship between classification of spiders , types of web build: species in same genus may build similar or different webs. nor there correspondence between spiders classification , chemical composition of silks. convergent evolution in web construction, in other words use of similar techniques remotely related species, rampant. orb web designs , spinning behaviors produce them best understood. basic radial-then-spiral sequence visible in orb webs , sense of direction required build them may have been inherited common ancestors of spider groups. however, majority of spiders build non-orb webs. used thought sticky orb web evolutionary innovation resulting in diversification of orbiculariae. now, however, appears non-orb spiders sub-group evolved orb-web spiders, , non-orb spiders have on 40% more species , 4 times abundant orb-web spiders. greater success may because sphecid wasps, dominant predators of spiders, prefer attack spiders have flat webs.

orb webs

nephila clavata, golden orb weaver

about half potential prey hit orb webs escape. web has perform 3 functions: intercepting prey (intersection), absorbing momentum without breaking (stopping), , trapping prey entangling or sticking (retention). no single design best prey. example: wider spacing of lines increase web s area , hence ability intercept prey, reduce stopping power , retention; closer spacing, larger sticky droplets , thicker lines improve retention, make easier potential prey see , avoid web, @ least during day. however, there no consistent differences between orb webs built use during day , built use @ night. in fact, there no simple relationship between orb web design features , prey capture, each orb-weaving species takes wide range of prey.

the hubs of orb webs, spiders lurk, above center, spiders can move downwards faster upwards. if there obvious direction in spider can retreat avoid own predators, hub offset towards direction.

horizontal orb webs common, despite being less effective @ intercepting , retaining prey , more vulnerable damage rain , falling debris. various researchers have suggested horizontal webs offer compensating advantages, such reduced vulnerability wind damage; reduced visibility prey flying upwards, because of back-lighting sky; enabling oscillations catch insects in slow horizontal flight. however, there no single explanation common use of horizontal orb webs.

spiders attach highly visible silk bands, called decorations or stabilimenta, webs. field research suggests webs more decorative bands captured more prey per hour. however, laboratory study showed spiders reduce building of these decorations if sense presence of predators.

there several unusual variants of orb web, many of them convergently evolved, including: attachment of lines surface of water, possibly trap insects in or on surface; webs twigs through centers, possibly hide spiders predators; ladder-like webs appear effective in catching moths. however, significance of many variations unclear.

in 1973, skylab 3 took 2 orb-web spiders space test web-spinning capabilities in 0 gravity. @ first, both produced rather sloppy webs, adapted quickly.

tangleweb spiders (cobweb spiders)

a funnel web.

members of family theridiidae weave irregular, tangled, three-dimensional webs, popularly known cobwebs. there seems evolutionary trend towards reduction in amount of sticky silk used, leading total absence in species. construction of cobwebs less stereotyped of orb-webs, , may take several days.

other types of webs

the linyphiidae make horizontal uneven sheets, tangles of stopping threads above. insects hit stopping threads fall onto sheet or shaken onto spider, , held sticky threads on sheet until spider can attack below.