Arthropod Roundup: Amphipods under the ice, high octane isopods, and the pea aphid genome

Quick blurbs about arthropod research and news:

• NASA climate researchers have discovered animal life deep below the Pine Island Glacier Ice Shelf in Antarctica. The researchers drilled a hole six-hundred feet deep and eight inches wide into the glacial ice sheet about twelve miles from the open ocean. When they lowered a camera below the ice sheet, the scientists were surprised to see a Lyssianasid amphipod crustacean swim up and park on the cable. The researchers were only expecting to find microbial life under the ice sheet this far in from the open ocean. It is unknown what the primary energy source for animals living here could be. The presence of a three-inch amphipod, however, suggests a much more elaborate and dynamic ecosystem than hypothesized in this poorly understood habitat. (DSN has a video of the amphipod)
• Limnoriid isopods, commonly called gribble worms for some reason (they neither are, nor resemble worms), have a ravenous appetite for wood. This is not unusual among arthropods; many diverse groups including termites, millipedes, and squat lobsters are capable of digesting woody plant matter. However, all these creatures process the wood with the aid of gut-dwelling symbiotic bacteria. A new study finds that the Limnoriid isopod, Limnoria quadripunctata is special in that it doesn’t rely on bacteria-produced catalysts to break down wood, but rather has the necessary glycosyl hydrolase enzymes incorporated into its genome. These enzymes are evolutionarily related to similar proteins found in arthropods, but their derived function for wood digestion in Limnoriid isopods is completely novel. The researchers, or their over-excitable university PR department, think the study of these enzymes could aid in bio fuel synthesis.
• The gemone of the pea aphid, Acyrthosiphon pisum, has been sequenced. This is the first Hemipteran (true bug) genome and will provide clues about the evolutionary history of certain hexapod groups. This new genome could also help agriculturalists develop new techniques to control aphid pests and the spread of aphid-borne plant viruses. Researchers are also interested in the pea aphid’s, apparently, scaled down immune response system and their ability to easily switch specialization from one plant species to another.

Deep-sea crustaceans on film and near-bottom ampipod swarms

The BBC is presenting an article and series of films from a recent University of Aberdeen research expedition. The films are shot between 5.5 kilometers and 10 kilometers in depth and feature snailfish, decapod shrimp, isopods, and amphipods as they scavenge on a bait bag. The videos are narrated by Dr. Alan Jamieson, and he shares some neat insights about deep sea life.

I am personally surprised at the ridiculous swarms of amphipods in the 9 km and 10 km videos. I did not think deep sea life was that dense except around vents and seeps. They don’t say how long the bait bag was there before the film starts, and it could have been down there for hours attracting every amphipod in a 100 m radius. However, a quick check of the literature reveals that these near-bottom deep-sea amphipod swarms have been observed near vents as well as in open abyssal plains. Pelagic swarming is not typically a characteristic attributed to deep sea crustaceans and its ecological significance is unknown.

A swarm of undescribed paradaliscid amphipods, photographed from the submersible Alvin near a deep sea vent in the East Pacific Rise (Dover et al., 1992).

References:
Dover, C.L.V. et al., 1992. Deep-sea amphipod swarms. Nature, 358(6381), 25-26.

Did Phronima inspire the design of the Alien Queen?

There is an interesting anecdote which claims that the amphipod crustacean genus, Phronima, served as the inspiration for the alien queen first seen in James Cameron’s, “Aliens.”

Photo: Pål Abrahamsen

The story seems to originate from David Attenborough’s narration in the “Blue Planet” documentary (Skip to 3:25 in this video for the scene in question). Some people around the web rebut this, stating that the original alien design was based on a painting by artist H. R. Giger. This seems to be the case as far as the original “soldier” alien morph seen in “Alien” (1979) is concerned. It is much more likely that Phronima actually influenced the design of the queen alien morph, seen in “Aliens” (1986).

I’ve tried to contact someone at the special effects company, Stan Winston Studios, but they seem to be hard to get a hold of if you are not the producer of a multi-hundred-million dollar blockbuster. Instead, lets talk a little about Phronima, which is an awesome animal regardless of whether or not it was the inspiration for the alien queen.

Arthrophoto: an Antarctic amphipod, Epimeria rubrieques

Photo: Torben Riehl, University of Hamburg

The antarctic oceans holds a surprising diversity of marine life, including this pointy amphipod crustacean. See other amphipods from the antarctic, here.