SICB 2013, day 3

It's nice to have a fitness center in a hotel. But you have to be willing to swallow your pride and do the walk of embarrassment from your room on the 17th floor, down through the lobby, around the corner, and back down into the sub-lobby, in your workout gear. This is easier at 5:00 am, which is when I woke up. My body is still on Central time, for which I am surprisingly grateful.

Never let it be said that tweeting to promote your talk is not worth it. Because Joel McGlothlin tweeted his talk, I went and saw it. He was talking about the evolution of garter snakes that resist deadly neurotoxin, which I’ve blogged about before. The wrinkle that Joel was bringing in is to look at is what order resistance evolved in. Different tissues have different kinds of sodium channels, so changing some will give you immunity to the poison, but only at low doses. If the amphibians get the ability to make more toxin, the snake needs another change in another channel to keep up.

Next, I saw Sonke Johnsen. He summarized some work on why giant squid have giant eyes. The answer, in broad strokes, was answered with "whales" a while ago. Sonke, in collaboration with others, has developed a general model of underwater visual ecology. Most of his talk had lots of equations, but the take home was that big eyes don't gain you very much because of water attenuation. The one advantage of a big pupil is looking at large, glowing objects. Like a whale setting of a lot of luminscence.

At the end, Sonke showed a picture of squid battling a sperm whale (this one), which was a cue for people to become marine biologists. “Hard not to after seeing that.”

Jean Alupay was looking at how often octopus are willing to lose one or more of their arms through autotomy. The particular species she was studying tend to autotomize their arms very easily. Over half were missing at least one arm. The front arms tend to be lost more, but there is a sex difference with the third arm, because that's where the sex organs are in males.

She showed some good video of a very active autotomized arm. It would be easy to see how it could distract a predator.

Feifei Qian had robots running through sand. Her question was how animals locomoting over sand deal with the variety in the size of grains, rocks, and boulders. This was more a robotics / automation talk than a biology talk.

However, she showed that automation is happening everywhere. She started off running her robots across sand in tanks that were maintained by undergrads. Initially, it two students two weeks working long hours to get preliminary data (67 runs). So instead, she built a completely automated system that reset the robot, sand, and boulders after each run. Now, this recording system can do a hundred trials in one day. She said she stills needs an undergraduate student though: she needs one student to take three seconds to press the start button.

Jayne Gardiner was interested in how sharks hunt. Sharks have a whole series of sensory abilities, that detect potential prey from close to tens of meters away. Do the senses combine, or do they switch from one sensory system to another?

My favourite moment in her talk was some video she showed of a bonnethead shark, where they had blocked electroreception. This left the poor shark completely unable to eat. The bonnethead shark can’t get food if the electroreception is blocked, because that’s the trigger for opening the jaws. They’ll swim in the tank all day, and hit the prey over and over and over again, but never open their mouths.

That's got to be a shark's version of hell.

Margot Schwalbe presented on a favourite of comparative biologists, African rift lake cichlid. Like most (all?) fish, these have canals that are part of the lateral line system that detect water movement. Are widened lateral line canals adaptations for prey detection? Some niche differentiation? She has two Lake Malawai cichlids species that feed on the same prey, but one has wide canals and one has narrow canals. The species with widened canals tended to use the lateral line system more than the narrow one.

Savithi Nair took me back to octopus arms for the second time today. She was looking at the behaviour of individual suckers in the arms. You might recall that probably half the nervous system of the octopus is in the arms, but how much do all those cells communicate? Is information shared between suckers? She found that they do, and that suckers do respond differently to different chemicals. The distance matters, as the reposes drops off with distance for the stimulus.

Still with cephalopods, Julia Samson showed that cuttlefish responses to sound. That cuttlefish can hear was not new, but her question was what sounds are ecologically relevant and matter to these molluscs? What behaviours occur in response to sound?

Cuttlefish don’t have "ears" in the proper sense; they're detecting sounds through organs called statocysts. Statocysts are more orientation and gravity sensors, but they way they work allows them to detect other kinds of disturbances. This means that the sounds have to be quite loud for cuttlefish to hear them. At high sound intensities, you get inking and startle responses. At lower volumes, the animals reacted with smaller colour flashes or fin movements.

David Ernst warmed my crustacean-loving heart by talking about ghost crab burrows on a beach. He showed that ghost crabs rarely return to their burrows. Any crab burrow is most likely to be occupied by a new crab every single night. This is a little surprising given the amount of time and energy that the crab has to invest in making the burrow.

Buddhamas Kriengwatana was the last talk I saw today. She was doing some nicely designed experiments testing how food shortages during development change the brains and behaviour of zebra finches. For instance, she found that continual food shortage means longer search times in finding mood, which means worse spatial memory. Being short on food late in development only specifically affected the finches on tests intended to measure their behavioural flexibility.

I had lots of interesting talks at the poster sessions that I can't summarize in full here, but remind me later to tell you the story of cryolite.