We're Moving!!

Hello Everyone!

I have been invited move Observations of a Nerd to Science Blogs, an opportunity I simply could not pass up. As such, this blog will be moving. This site will remain as an archive and in case I ever decide to leave, but for the forseeable future, Observations of a Nerd will be found at http://scienceblogs.com/observations.

The new feed is: here , so please update your subscriptions. I hope that all of you will continue to follow this blog and will join me over at Science Blogs! 

Aloha,
Christie

Picky Octopuses Don't Settle For Less Than The Best HDTV

Octopuses* and their cephalopod relatives are some of the smartest animals on the planet. Accordingly, many scientists want to understand how their mind works. To gain insights into the complex minds of cephalopods, researchers have been studying behavior in individual animals for years by presenting different animals with various visual stimuli. But many of the methods have downsides - for example, if you want to see how an octopus reacts to another octopus, you can add an octopus to the tank, but doing so introduces other variables. There may be variation in response based on how the introduced octopus looks, moves, etc, and these factors are hard to control. Ideally, you'd want something that you could repeat exactly every time - like a movie.

When researchers have tried in the past to use movies to stimulate behavioral responses, however, they found that the octopuses didn't respond. They weren't sure exactly why. Mirrors and pictures revealed that octopuses can clearly see the 2-D images, so that's not the issue. It was as if they just weren't interested in videos.

Dr. Renata Pronk and her colleagues from Macquarie University had a theory - they thought that the octopuses didn't believe them. Cephalopods rely heavily on their sight, and their vision is highly developed, so it's possible that the animals easily realized that poor quality videos weren't real life. If this were the case, Pronk realized, octpuses might respond to the breakthrough visuals of HDTV.

To test this hypothesis, she collected wild gloomy octopuses (Octopus tetricus) and subjected them to high-definition videos of things that might interest an octopus - a tasty crab, another octopus, or a jar to play with.

Incredibly, when she played the first video of a crab for her first test octopus, it grabbed at the screen. HDTV fooled it! Heres a video of a thoroughly-tricked octopus c/o New Scientist:


With their method working, the researchers tested 31 octopuses on 3 different days over a ten-day period to see if their behaviors varied temporally. Furthermore, they compared the individual animals, to look for evidence of personalities.

Behavioral biologists define a "personality" as behavioral differences between individuals that are consistent over time and across ecologically important contexts. In other words, Pronk wanted to know if some octopuses are consistently more aggressive or passive than others when exposed to the same situation.

The researchers found that the octopuses did react differently from each other, but they also reacted differently on different days. Some days they were highly reactive, other days they were less so. There was no consistent reaction from a given octopus.

These data suggest that octopuses have what is called "episodic personalities." This means that they do show differences in behavior between individuals, but they also show differences over time. This isn't necessarily "bad" or suggest they are "less intelligent." Indeed, this may be a sign of their intellect - after all, humans exhibit individual and temporal variation in behavioral response, too.

Moreover, this study gives biologists a new method to study octopus behavior. Of course, the most important questions have yet to be answered - like which American Idol contestant the octopuses will root for, or whether they will detest Jersey Shore as much as I do.


*Not Octopi. I was very disappointed to learn that it's not Octopi.

Citation:
Pronk, R., Wilson, D., & Harcourt, R. (2010). Video playback demonstrates episodic personality in the gloomy octopus Journal of Experimental Biology, 213 (7), 1035-1041 DOI: 10.1242/jeb.040675

Duck to avoid parasites

During the summer, strange formations can be found on some species of Goldenrod. The stems become enlarged and form a hardened golf-ball like object called a gall. Cut into this weird sphere and you'll quickly find what causes the plant to create such a strange object: the larvae of the Goldenrod Gall Fly.

The Goldenrod Gall Fly (Eurosta solidaginis) is a parasite which uses the Goldenrod for protection and nutrition for a whole year while it grows and pupates. When it does, it can seriously damage the Goldenrod, even prevent the plant from flowering and producing seeds. This is a serious blow to the plant, so the Goldenrod doesn't just take this kind of damage laying down. When the flies are flitting about searching for rods to lay their eggs in, the rods in turn try to avoid their pests in a very recognizable way: they duck.

Scientists had found that during the few weeks that adult flies spend mating and laying their eggs, some Goldenrod stems undergo an odd behavior: they stop growing upward and instead curl and grow downward, creating a "candy-cane" like stem (see L). Once the mating season is over, they straighten up again, just in time to flower and seed.It had been found that this odd downturn made the rods twice as resistant to the flies, but scientists weren't sure if it was the behavior causing this resistance or something intrinsic about those plants that made them resistant and turn down.

Luckily, they discovered that bent plants straighten when placed in the shade, and this gave them the unique and rare opportunity to investigate causation. Researchers took both straight and bending plants and place them in a greenhouse both in the sun and in the shade. As the shaded bent plants un-curled, they set Eurosta solidaginis upon the lot, and recorded which ones ended up parasitized.

The straight variety were parasitized heavily whether in the sun or the shade. But the 'ducking' plants completely avoided parasites - if they were still bent (see R). Those that began to straighten by being placed in the shade were parasitized just as much as the non-bending variety, strongly supporting the hypothesis that the bending behavior itself created the observed resistance to parasitism.

Moreover, the experiment explained why the ducking behavior works. Unlike when people duck, the plants did not cause the flies to miss. Indeed, female flies often landed on the bent stems. However, the researchers explained, the flies appeared confused or disoriented by the plant's behavior. It's possible they didn't recognize the bud where they usually lay because of its orientation, or interpreted the bend as a damaged or unhealthy plant that won't last long enough to nurture their young. For whatever reason, the female flies decided that the plant was not a good choice, and moved on to other plants instead of depositing eggs.

The researchers have yet to understand, though, why the bending behavior is relatively rare in Goldenrod populations. Their future research hopes to learn more about how this behavior occurs.

Wise, M., Abrahamson, W., & Cole, J. (2010). The role of nodding stems in the goldenrod-gall-fly interaction: A test of the "ducking" hypothesis American Journal of Botany, 97 (3), 525-529 DOI: 10.3732/ajb.0900227

Weekly Dose of Cute: World's Biggest Bunny!

Often, the cutest things come in small packages. Not so with Ralph - at 42 lbs, he's a record-breaking rabbit.

Ralph comes from a huge family - both his mother and father previously held the world records for largest rabbit in length and weight. And though he's already the biggest bunny in the world, Ralph is still growing! No one knows how immense this ball off fluff will get, but however big he ends up being, he's sure to still be 100% adorable.

Link Love, etc

First off, the e-mails have been sent, and if you're a member of ResearchBlogging.Org, then you should haev a vote to cast in the ResearchBlogging Awards! So go vote for Observations of a Nerd for the best lay-level and biology blog as well as best research post of the year *cough* *cough* your favorites!

If you aren't a member, then I guess you'll just have to wait to see what happens. Good luck to all the contestants!

Anyhow, I've been awful busy this week starting my last rotation in a whole new lab, so I've been lagging on the goods. If you follow my twitter, you've gotten a little more, but for everyone else here are some fun things to go check out:

Carl wants to give in to the microbes - what do you think?

A little warm and fuzzy after that: A dog and his feline best friend

Need something to do? How about you take your peeps places!

And of course, the most important question you'll get asked all day: Do your balls hang low?

Hopefully that'll keep y'all busy until I can force myself to sit down in front of the computer a little longer and give you a real post.

(and, PS, if you're still bored, scroll down a little and check out the "Fun Reads" and "Other Fun Reads" sticky notes on the right-hand side of the page...)

Bejeweling bugs to inspire bioadhesives?

Remember those perhaps gross but cool insect jewelry artists I mentioned before? Now, their incredible tube-making skill might be used in an entirely different field: medicine.

Dr. Russell Stewart, an assistant professor at the University of Utah, has been studying natural adhesives for years. He was drawn to the caddisfly because it's one of the few creatures in this world to have accomplished a very difficult feat: it sticks things together underwater.

Creating an adhesive that works when wet isn't easy - just think of what happens to your average band-aid in the shower. But the caddisfly has mastered underwater engineering, and Stewart wanted to know exactly how it sticks together its living quarters.

Like many other organisms including spiders and silkworms, caddisfly larvae spin silk. It's their silken strands that stitch together their makeshift mobile homes. But scientists didn't understand how this worked while underwater - until now. A new study published online first in the journal Biomacromolecules reveals the caddisfly's architectural secrets.

The caddisfly larvae uses its silk like tape, researchers explain. They took larvae and placed them in aquaria with glass beads. Once the bugs had created their homes, the researchers analyzed their homes with a wide variety of technical tools, including scanning electron microscopy. The SEM images on the right show the criss-crossed strands of silk that have woven together the beads into the larvae's tube.

They learned that unlike the silk produced by terrestrial creatures, the caddisfly's silk works underwater because it's covered in phosphates (blue color in image F). Up to 95% of the serine residues in the silk protein are phosphorylated! We use phosphates in our own adhesives, including fillings and latex paints. In the caddisfly, these negatively-charged groups line up with positively charged proteins and cations like calcium, and the strong attraction between them holds the fiber together.

What's so special about this adhesive is that it can be used on just about anything, as artist Hubert Duprat found out when he placed caddisfly larvae in aquaria with gold flakes and precious gems. Their silk can bind all kinds of things, and this unique trait may make it an ideal candidate for medical use.

The hope is that since caddisfly silk works when wet, it could inspire a new kind of way to suture surgical wounds or even help repair small bone breaks. Characterizing the silk fibers is the first step towards copying the caddisfly's technology and creating a new line of medical glues or tapes that one day may replace sutures or stitches in sealing up wounds.

Stewart, R., & Wang, C. (2010). Adaptation of Caddisfly Larval Silks to Aquatic Habitats by Phosphorylation of H-Fibroin Serines Biomacromolecules DOI: 10.1021/bm901426d