Leslie Brunetta

People and other animals have always adapted spider silk to their own purposes. Here's a spectacular piece of footage from Jeremy Wade's Animal Planet "River Monsters" series showing a skillful South Pacific fisherman using Nephila, or golden orb weaver, silk as an all-in-one tool. Notice the golden hue of the silk, and just how stuck into the tangled silk the fish gets. I wonder whether the aggregate silk protein glue that lies along the web's capture spiral survives its swish through the salt water and that's what the fish sticks to, or whether the fish simply gets major ampullate and flagelliform silk wound around its teeth. Thanks to Green Matter for the tip.


 Read More 

Here's a report of gossamer masses startling people living in the Macedon Ranges shire of Victoria, Australia. The ability of young spiders to balloon is made possible by super-strong major ampullate silk, the silk araneomorph spiders use to rappel and to construct the strongest lines of their webs. Jumping spiders use it as their safety line. You can read more about ballooning in Chapter Five of Spider Silk, "Triumph Over Thin Air." One of my life's goals is to witness such a mass gossamer waft. Read More 

If you're not already one of the two-million-plus viewers of Hummingbird Cam, check it out soon to catch the current chicks before they fly the nest. Don't fret if you miss them, because the mother will soon lay another clutch of two eggs if she sticks to her pattern of previous years.

But whether the nest is full or empty, take a close look at it. The mother hummingbird has bound all her building materials together with spider silk. Spider silk offers this mother the perfect combination of strength and flexibility: the nest actually stretches with the growth of the chicks.

Hummingbirds aren't the only birds to use spider silk in nest building. I haven't been able to find any research on whether birds are picky about the kinds of spider webs they choose to filch. Do they prefer araneoid webs, with their super-stretchy flagelliform catching lines and aggregate protein glue? Or non-araneoid araneomorph webs, with their dry cribellate catching silk? Do different birds prefer different kinds of silk? If you know of any research pointing to answers, please let me know. Read More 

Part of the reason it's so difficult to create synthetic spider silk is that we still don't know exactly why natural spider silk is so strong, stretchy, or tough. We have a general understanding: certain arrangements of silk protein molecules give rise to these various properties. But we're still trying to figure out exactly what's going on at the scale of the atoms making up these molecules. We know that silk fibers are made up of both crystalline subunits, in which the molecules interlock in very organized and repetitive patterns that give rise to strength, and "amorphous" subunits, in which the molecules are relatively disordered. The amorphous subunits lend the fiber the ability to deform, which allows it to stretch or absorb impact. Still mysterious is exactly how these subunits arrange themselves and connect within the total unit of a silk fiber. After all, to know this we would have to be able to view the atoms within the fiber molecules directly. We can currently view them only indirectly, using technologies such as x-ray crystallography.

But researchers can use existing knowledge of silk protein structure to build and test models of how these atoms might link together. After playing with different proportions and arrangements of the two types of subunit, a team of researchers from Germany and China have proposed a new model that they believe could help in the design of synthetic spider silk. Even if you're an English major (like me), if you've read Spider Silk, you can skim this paper and get the gist of it. If you want a precis, you can read this article from Deutsche Welle, which ends with a much-appreciated plug for arachnology. But like so many articles on spider silk research, this one, too, is mistitled: although this research offers a promising approach to synthesizing a fiber like spider silk, we still haven't untangled all the secrets of real spider silk. Read More 

Here's an excerpt of David Pogue's Making Stuff: Stronger episode, taken from the PBS News Hour:



Later in the episode, Randy Lewis gives a nifty explanation of dragline silk protein's strength using Legos, springs, and zippers. If you want to learn more about how such an extraordinary material has evolved, read Chapter 6 in Spider Silk. And if you get a chance to catch the whole episode in future, it's well worth your time.  Read More 

CBS News has a preview of David Pogue's spider silk segment on his new Nova: Making Stuff series on PBS. This should be fun. I'm interested to see whether Randy Lewis or any other spider silk experts get a chance to explain why copying spiders' ability to make silk in the quantities we desire is so difficult.  Read More 

Milestone: An academic paper has cited Spider Silk. We wrote Spider Silk for nonscientists, and it's been gratifying to receive reviews praising our book as "conversational," "easy to read," and "difficult to put down." But it's also great to know that other biologists recognize the validity of the science supporting our narrative. Although spiders make and use silk in unique ways, many other arthropods also use silk for various purposes. Miki Kanazawa, Ken Sahara, and Yutaka Saito of Hokkaido University in Japan have discovered that female Stigmaeopsis longus, a species of social spider mites, use silk threads to clean their communal nests. If you're interested in what it might be like to live in a highly humid, capsule-like nest with tens of others of your kind, the eye-opening introduction to their paper gives a glimpse of some of the grittier aspects. But of course, if you were this self-regarding co-author, the true frisson would kick in at footnote #27.  Read More 

A new paper on how assassin bugs play on the web strings of spiders to lure them to their untimely end got a lot of publicity this week for good reason: "aggressive mimicry," in which a predator imitates something (for example, prey or a potential mate) that its prey is instinctively primed to approach, is intriguing on a number of counts. The paper, by Anne Wignall and Phillip Taylor of Macquarie University in Australia, details experiments they conducted to discover how the araneophagic Stenolemus bituberus tricks spiders into coming along the web to have a closer look. Mark Kinver at the BBC, Duncan Geere at Wired Science, and Jennifer Viegas at Discovery News all have good summaries.

But these summaries all focus on the assassin bug and its remarkably skillful underhandedness. I can't help but focus on the spider. Read More 

Genetics papers can be pretty impenetrable to us non-geneticists. But geneticists don't write the way they do just so they'll be perceived as eggheads.

It took me, an English major with not much science background beyond high school courses, many months to learn how to decipher the genetics papers that inform Spider Silk. Of course, I was lucky enough to have Cay Craig guide me through these papers and steer me back on track when I veered astray. During this process, I came to realize that genes and genetic research is even more complicated than most of us non-biologists realize. For many of us, it's a mystery why news reports about exciting discoveries in genetics don't lead rapidly to successful medical or other practical applications.

I now get that it's no mystery, or conspiracy. This longer-than-usual post is an attempt to walk through an intriguing paper by a genetics team that writes unusually clearly. Even so, the paper is shot through with terms such as "paralog," "diploid," "retroposition," and "fluorescence in situ hybridization." These terms immediately convey images and lines of logic to other geneticists but gaping black holes to the rest of us. I'm going to avoid such terms as much as possible as I walk through the paper. But I think you'll still see how many interlocking and complex concepts and techniques evolutionary geneticists have to wrestle with, and why even dazzling genetics papers usually lead to more papers rather than to immediate, dramatic applications.  Read More 

We recently wrote about golden spider silk woven into a traditional Malagasy tapestry. Spider Silk co-author Cay Craig is just back from Madagascar, where she spearheads the Conservation through Poverty Alleviation project, known as CPALI for short. And she's brought lengths of a brand new kind of Malagasy textile made from bronze-colored native silk moth silk.



It's impossible not to pun that silk has threaded together various places, projects, and insights over the past 30 years of Cay's life. Cay first knew she wanted to make field research her life's work when she spent time as an undergraduate in Stanford's Human Biology program working with Jane Goodall at Gombe in Tanzania. Working later in Costa Rica, she realized that spiders and their silks would allow her not only to combine field research with her more recent interest in evolution but also to conduct experiments that would be impossible with larger or more mobile animals. And so her career as an arachnologist and eventual authority on silks and silk proteins began.

Visiting Gombe in 2002, Cay was devastated by the intervening damage to the forests surrounding the national park. She believed local people often had no option but to rip into the forests surrounding their villages in order to gain cropland or firewood. If there was some way to provide them an economic incentive to plant rather than cut down trees, she figured, they might gain a little more control over their economic situation and revitalize the buffer forest around the park at the same time.

That's what CPALI is doing at the edges of the Makira Protected Area in Madagascar – home of the silky sifaka and also site of some of the worst illegal rosewood harvesting. The latest tangible result is a length of bronze-colored, diaphanous textile created by sewing together hundreds of ironed-flat silk moth cocoons.

With the light shining through it, this textile is otherworldly and yet earthy, seeming simultaneously mineral and animal. A number of designers are interested in its possible use in wall coverings, lampshades, and window treatments. As sales increase, more farmers can join CPALI and additional forest loss to slash and burn agriculture avoided. Read More