New Species from Australian Reefs

You probably saw all the posts about the new species found on and in the Australian reefs from the recent Census of Marine Life efforts there.

The video of Heron Island sampling at the CoML website is a great watch, good invert sampling in the last half of the video.

A second video from New Tang Dynasty Television is available on YouTube which actually does a decent job of reporting on the discoveries, including showing a good photo of the tongue eating isopods (outside of their hosts).

Isopods Cause Reproductive Death in Shrimp

Isopods, you know them as those adorable little roly-poly bugs under rocks in the forest or the gigantic Bathynomus of the deep sea. They are also those cute and cuddly parasites in the gill chamber of shrimp too! Awww, How special! In the recent issue of JMBA-UK, Calado et al. describe how these fuzzy wittle darlings castrate their shrimpity hosts.

The isopod in question is the Argeiopsis inhacae, a member of the parasitic family of isopods - Bopyridae. They don't start off as the lovely parasite "friend" of shrimp. The larvae begins life as a free swimmer until it finds a copepod to attach itself too, then metamorphoses into another larval stage and looks to buddy up with the nearest shrimp it can find.

Calado et al. found that when pairing unparasitized males and females together, females laid perfectly fine clutches of eggs. However, when unparasitized males were paired with females containing the isopod, there were never any egg clutches laid. This is in spite of similar courtship behavior and no differences in moult patterns. Furthermore, parasitized adult female shrimp did not develop a key feature denoting fertile production, a bright green spot on the back that marks the presence of large yolky oocytes. It appears that this bopyrid isopod causes "reproductive death" in females Stenopus hisidus. Unfortunately, they never tested whether parasitized males can make viable offspring. It is still not known whether parasitism is sex-biased or appears as such because of the author's limited sampling.

This short study is interesting because it is the first experimental study to nail down reproductive cessation due to the isopod parasite. What use is it to stop reproduction? One reason may be to divert the host's resources away from reproduction, an energy expensive process. The isopod would ensure its survival and its continuance to leech off the shrimp.

The isopod, Argeiopsis inhacae, forces the shrimp's carapace to bulge, as it grows inside the branchial chamber. Figure 2 from Calado et al. (2008).

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Calado, R., Bartilotti, C., Goy, J.W., Dinis, M.T. (2008). Parasitic castration of the stenopodid shrimp Stenopus hispidus (Decapoda: Stenopodidae) induced by the bopyrid isopod Argeiopsis inhacae (Isopoda: Bopyridae). Journal of the Marine Biological Association of the UK, 88(02) DOI: 10.1017/S0025315408000684

Dreamlines

Peter sent me the coolest thing I've seen on the net in ages! The website, Dreamlines,

"is a generative drawing machine that creates a unique, ever-flowing painting after words you choose. Related images are gathered from the Net and used as raw material for the construction of your personal dream.

...The key of the piece lies in the translation between two different sets of coordinates: color and movement. The images are never actually shown. The visual output is the result of the endless drifting of a swarm of 1500 autonomous particles. The loaded images are a sort of virtual terrain for them. The direction and speed of each particle is given, at each step, by the color values of the pixel it is stepping on. The resulting path is traced to the screen, and the accumulation of them forms the dense drawing seen by the user."

Here are a few of my own drawings for "invertebrate"!

Glamorous Insects!

A friend sent me this webpage from Dark Roasted Blend on Glamorous Insects. Though they are not all insects, these unbelievable macro photos are better than National Geographic quality. I will steal one just to get you to go over there and see the rest! I really love the mantids.

Rock Eating Isopods

Photo credit: Yuji Okimura, emeritus professor at Hiroshima University.

What is the buzz on CRUST-L these days? How about isopods on an island off of Hiroshima in Japan that have eaten away the soft volcanic rock (called tuff) to almost sea level! In a recent news piece from MSN-Japan they document a dramatic change in the small island's stature from 1955 to the present (click on link to see and read the article in its entirety). These isopods burrow into the rock, possibly to eat at bacteria and algae and hide from predators, speeding up erosion big time. The island once stood 21.9 meters tall in 1928 and now, as the article states,

"...the highest peak has almost completely vanished, leaving only one rocky protrusion about 6 meters high. Because of this, most of the island is submerged at full tide."