Other researchers have identified a kind of master circuit of 16 neurons that connect the dragonfly’s brain to its flight motor center in the thorax. With the aid of that neuronal package, a dragonfly can track a moving target, calculate a trajectory to intercept that target and subtly adjust its path as needed.

The scientists found evidence that a dragonfly plots its course to intercept through a variant of “an old mariner’s trick,” said Robert M. Olberg of Union College, who reported the research with his colleagues in Proceedings of the National Academy of Sciences. If you’re heading north on a boat and you see another boat moving, say, 30 degrees to your right, and if as the two of you barrel forward the other boat remains at that 30-degree spot in your field of view, vector mechanics dictate that your boats will crash: better slow down, speed up or turn aside.

In a similar manner, as a dragonfly closes in on a meal, it maintains an image of the moving prey on the same spot, the same compass point of its visual field. “The image of the prey is getting bigger, but if it’s always on the same spot of the retina, the dragonfly will intercept its target,” said Paloma T. Gonzalez-Bellido, an author of the new report who now works at the Marine Biological Laboratory in Woods Hole, Mass.

Read more…

Cuttlefish are ugly-cute. With their big eyes, stubby tentacles and bulbous head, they look like creatures from an H.P. Lovecraft horror story. When they move forward — rippling their fins underneath their bodies — they look like prehistoric flying saucers. They hunt at night and are masters of disguise.

It turns out that this last attribute may have value beyond the sea. New research is showing that cuttlefish and their squid cousins may hold the key to creating new kinds of camouflage to mask clothes, buildings and vehicles.

Unlike any other animals, cuttlefish and squid use light to blend into or stand out from their surroundings. Marine scientists believe they do this using tiny sensors all over their skin that help them change color without sending messages to the brain. Exactly how it works is still a mystery.

Roger Hanlon, a senior scientist at the Marine Biological Laboratory in Woods Hole, MA, is collaborating with bioengineers across the country to develop a material that mimics this camouflage mechanism. The material might be able to hide objects or change the tint of your car. It might even allow buildings to keep cool in the summer and warm in the winter by darkening to absorb heat and lightening to reflect it.

Read more…

We tested our cockroach leg stimulus protocol on the squid’s chromatophores. We used a suction electrode to attach to the squid’s fin nerve, then connected the electrode to an iPod nano as our stimulator. The results were both interesting and beautiful. The video below is a view through an 8x microscope zoomed in on the dorsal side of the fin.

We’d like to give a shout out to our gracious and brilliant hosts for making this possible: the Methods in Computational Neuroscience and the Neuroinformatics Courses at the MBL. Paloma T. Gonzalez-Bellido of Roger Hanlon’s Lab in the Program in Sensory Physiology and Behavior of the Marine Biological Laboratory helped us with the preparation. Paloma studies iridophores (iridescent cells) of the squid. You can read their latest paper at the The Royal Society.

Update: There are some questions as to what is happening and how this works. An iPod plays music by converting digital music to a small current that it sends to tiny magnets in the earbuds. The magnets are connected to cones that vibrate and produce sound.

Since this is the same electrical current that neurons use to communicate, we cut off the ear buds and instead placed the wire into the fin nerve. When the iPod sends bass frequencies (<100Hz) the axons in the nerves have enough charge to fire an action potential. This will in turn cause the muscles in the chromatophores to contract.

Program in Sensory Physiology and Behavior Seminar