Tag Archives: spider

Sticky End for a Carpenter Bee

July 2, 2013 Tim Jones Leave a comment

Carpenter Bees look like Bumble Bees, but are black all over with an almost hairless abdomen. A penchant for boring into wooden structures to make their homes makes them unpopular with owners of wooden homes – understandably.

Carpenter Bee Caught in Spider Web (Photo: Tim Jones)

I snapped this one, dead, hanging directly over the back door porch. Which is a little worrying, seeing as the web it’s hanging from belongs to one of these guys:

One I took earlier. Black Widow Spider (Photo: Tim Jones)

Recognizable by its bulbous abdomen and red hour-glass insignia, the Black Widow spider weaves a characteristically disheveled web. This Western Black Widow, Latrodectus hesperus, is the only kind found in California. (Reminder again that I’m visiting the US at the mo’; we don’t get these in the UK – thankfully.)

The popular myth that a Black Widow bite will, guaranteed, kill a person outright dead everytime seems a bit overblown (ref. University of California.). But reports of painful muscle cramps, fever etc. suggest gloves are a good idea if you’re clearing out that dark corner of the garage; that’s where we found this guy.

See how in the top photo the web shines so nicely in the backlight? That property, combined with the phenomenal strength of spider silk, wasn’t lost on the US military who, during World War II, harvested Black Widow spider silk for use as the cross-hairs of gun-sights (ref. Popular Science March 1944)

Here are some Carpenter Bees in happier times:

Carpenter Bee on the wing (Photo:Tim Jones)

animals, Uncategorized

Orderly Animals

July 25, 2012 Tim Jones Leave a comment

Gee, humans are smart. Never mind the moon landing, today we have these fantastic slide-away pantries to squirrel our stuff away. The ultimate in mall to wall storage efficiency.

Then again, maybe that honor should go to the first of two non-human tidy housekeepers that crossed my path this week: the Acorn Woodpecker (Melanenpes formicivorus):

I’ve written about woodpeckers before – HERE. But this example, snapped in Santa Barbara Zoo (of all places, given the birds are all over the area) is the best example of an acorn-saturated tree trunk I’ve seen. Acorns placed by woodpeckers into holes excavated by woodpeckers – for later consumption.

Tidy Trashlines

Next up, the Trashline Orb Weaver spider (genus Cyclosa). I came across this guy on a pick-your-own blueberry adventure at nearby Gaviota, strung across the bushes. (And vulnerable to accidental picking – it’s likely I ate one of these.):

spiderweb3 — Trashline Orb Weaver Spider

The spider is the darker lump at the center of the web, hidden among the string of five packages: its ‘trash’, made of bits of old victims, egg sacs, plant material and such like caught in the web. I’d never seen one before, but now I now about them I’ve spotted a couple more in other locations. Here’s one, startled to life below a vertical, albeit incipient, trashline:

spider home — Trashline Orb Weaver Spider

Left alone, they pull in their legs and try to look like a piece of trash:

Incidentally, in the top picture you can see a visibly thicker, extra-strong, ‘cross-beam’ section of webbing, the stabilimetum, on which the main web and trashline hangs.

Why go to the trouble? Spider researchers reckon the trashline disguises the spider from approaching food insects, which can then be grabbed more easily; but also hides it from predators ~ a strategy more effective against birds than wasps (ref 1).

Yeah, we’re smart – in some things; but we’re not the whole story by a long shot.

Of related interest

‘Decorative Spider Webs Attract Dinner‘ (BBC item from 20/9/12)

References and further reading

1. Detritus decorations of an Orb-Weaving spider (Cyclosa mulmelnensis): for food or camouflage ? Tan E. & Li D., Journal of Experimental Biology, 2009, DOI 10.1242/jeb 030502 (pdf here)

2. Insectidentification.org

3. Trashiline Orb Weaver – A cool spider (abundantnature.com)

Photos copyright Tim Jones

animals, biology, Experiments, nature

A Web of Intrigue

October 8, 2010 Tim Jones Leave a comment

I got up yesterday morning at what for me is quite an early hour – 6.30ish. So with no CSI on the box at that time, I chose the healthy option and went for a walk in the park. Where I took this picture:

spider web with water droplets — Spider web with water droplets (Photo: Tim Jones)

That’s only kind of true. What I actually took was this picture:

and only later discovered the fine structure of water droplets clinging to the spider’s thread when I got home and fired up the computer.

A beautiful and fascinating sight. But, as per usual, the deeper beauty is in the science behind WHY droplets deposit in such regular patterns.

One Google later, I’d found this relevant study described in a Nature News piece (full research paper doi:10.1038/nature08729 behind pay-wall; also as per usual…).

The News piece describes work by Lei Jiang from the Beijing National Laboratory for Molecular Sciences on the hackled orbweaver spider Uloborus walckenaerius. The authors found that if you get in close enough, spiders’ silk appears not as a simple thread but is covered in puffs of minute nanoscale fibres. When the puffs get wet they contract into tight beads or knots connected by thinner pieces of silk, necklace fashion. Additional water migrates and accumulates on the rough surface of the knots in preference to the smoother connecting silk, forming the uniform droplets we see. The research also inspired thoughts around practical offshoots, like the possibility of a man-made equivalent for the manufacture of highly water absorbent materials.

I didn’t see any ‘puffs’, but I’m pretty pleased with the resolution I achieved with a good but relatively straightforward camera. That said, I’m feeling the need to get some of that spider silk under the microscope.

Here’s one more picture taken on the same day, of a single strand of web stretching between two trees; would you believe a distance of over 20ft?

Single filament spider silk (Photo:Tim Jones)

The water is clearing from one portion, and the dry filament is just visible in the close-up view. In the technical jargon, we can say the ratio of droplet size to silk diameter is ‘amazing’.

And if you’re wondering where the spider/s were all this time? Me too. For the arachnophiles, here’s one I took earlier.

Communicate Science

Tag Archives: spider

Sticky End for a Carpenter Bee

Orderly Animals

A Web of Intrigue

Zoonomian Blog