Advantages/purposes of different web types?

[Lambda Tau]

As the question states; where might an orb-web be preferable to a sheet web? A funnel-web to a cob-web? Could someone please break down the web types and their purposes, or direct me to a source that explains it?

 

[Ungoliant]

As the question states; where might an orb-web be preferable to a sheet web? A funnel-web to a cob-web? Could someone please break down the web types and their purposes, or direct me to a source that explains it?

Rainer Foelix's Biology of Spiders has a whole chapter on spider webs. It starts with an explanation of silk production, silk properties, and different types of silk. I highly recommend this textbook if you are seriously interested in spiders.

Some brief excerpts:

Sheet webs are built by Agelenidae and by Linyphiidae, yet those sheets differ as much in their structural details as does the behavior of their respective inhabitants. The Agelenidae weave a flat, slightly concave silk mat with a funnel-shaped retreat at one end (fig. 1.7). There the spider hides and rushes out only when prey has blundered into the web. The webs of Tegenaria commonly bridge the corners of rooms in European houses; the corresponding agelenid in North America belongs to the genus Agelenopsis. The much smaller Agelena prefers the outdoors and is abundant in grass and low bushes. Its web consists of a sheet measuring, at most, 40–60 cm, suspended by oblique and vertical threads. Flying insects hit these vertical threads and drop onto the sheet.

The very delicate webs of the linyphiids are also horizontal, but convex, sheets with similar vertical threads that serve as tripping lines for insects (fig. 5.20). Some silk threads of the linyphiid web contain sticky droplets, but these do not play a significant role in catching prey (Benjamin et al., 2002). In most cases an insect becomes trapped between the vertical "knock-down" threads. The spider, hanging beneath its sheet, quickly rushes by and shakes the web so that the victim will fall down. The bite is applied through the fine meshwork of the horizontal sheet, and the victim is pulled down. The damage done to the web is mended after feeding.

Linyphiid webs are built in sections over several days and last for a long time (Benjamin and Zschokke, 2004). Some species add a second smaller sheet under the main dome.

To a certain extent the frame webs of the theridiids resemble those of linyphiids. The structure of the sheet, however, is very loose and irregular, and the trapping threads are regularly studded with glue droplets (fig. 5.21; Wiehle, 1949). These threads are attached tightly to the substrate and break easily when an insect (often an ant) touches them. The insect is then glued to the broken thread and suspended helplessly in the air. While trying to free itself, the animal contacts neighboring catching threads and becomes progressively more entangled. Meanwhile the alerted spider quickly climbs down and eventually has to squeeze through the dense mat of the tangle web (Barrantes and Weng, 2006). Sticky threads are then flung over the victim with the hind legs (fig. 4.3d), before biting it.

The orb web as a whole is thus a combination of strong frame and radial threads with a very elastic catching spiral. Frame and radii provide a mechanically stable construction, which is also well suited for signal transmission (courtship plucking, prey vibrations). The elastic capture thread is an adaptation to struggling prey; the impact and movements of an insect cause little damage because the kinetic energy is largely absorbed by the yielding catching spiral and turned into heat (Denny, 1976; Lin et al., 1995). Even the radial threads have a remarkable extensibility (40%) and thus also function as shock absorbers when prey flies into the web (Köhler and Vollrath, 1995).

 

[Lambda Tau]

Rainer Foelix's Biology of Spiders has a whole chapter on spider webs. It starts with an explanation of silk production, silk properties, and different types of silk. I highly recommend this textbook if you are seriously interested in spiders.

Some brief excerpts:

Excellent information, I'll make a note of that book, it seems very interesting. Thank you

 

[Veles]

As the question states; where might an orb-web be preferable to a sheet web? A funnel-web to a cob-web? Could someone please break down the web types and their purposes, or direct me to a source that explains it?

Regarding the sheet webs, they are pretty prone to getting invaded by predators.

 

[Lambda Tau]

Regarding the sheet webs, they are pretty prone to getting invaded by predators.

Do you know what their advantages are then, or why a spider might evolve such a vulnerable web?

 

[FrDoc]

@Ungoliant, they obviously desire you post the book. Seriously folks, if you want to truly lay a foundation for understanding spiders deeper than others’ anecdotes posted on various forums (as good as that is), get off your wallets and buy this book. If you’re serious about spiders, you’ll read it, then refer to it often. It’s well worth the cost.

 

[The Snark]

Consider this. Take one example given us by the Latrodectus folks. Seven extremely powerful complex venoms, one of which targets crustaceans. Certain predictable traits and habits found in the southern regions of Europe, swampy areas of the northern east coast of the US, on the borders of Death Valley and the area around Darwin. A mass of the strongest naturally occuring fibers known in a completely random web yet only three sticky lines to capture prey.
This didn't happen overnight. Eons are involved in developing these traits, habits and capabilities. And one of the few clues as to the how and why, an in depth analysis of the webs of spiders and how they correlate to the evolution of the spider capabilities is certainly in order if we wish to understand these remarkable animals.
Grabbeth dat book.