Tag Archives: crustacean

The Lazy Bird Gets the Worm

A fine-scale analysis reveals microgeographic hotspots maximizing infection rate between a parasite and its fish host (2021) Mathieu-Bégné et al., Functional Ecology, https://doi.org/10.1111/1365-2435.13967

Image credit: Viridiflavus via Wikimedia Commons, CC BY-SA 3.0

The Crux

Interactions between hosts and parasites can be broken down into two broad stages: the encounter filter and the compatibility filter. The encounter filter determines whether a parasite actually comes in contact with a host, through either a spatial or temporal overlap. After the encounter filter comes the compatibility filter, the stage at which a parasite either successfully infects a host and takes the resources needed, or is successfully repelled by the host. Though the encounter filter must come before the compatibility filter, most studies tend to focus on the compatibility filter. Yet for a parasite to successfully encounter a host, many obstacles must first be overcome.

Parasites tend to be very small, and hosts tend to be rare. Furthermore, many hosts move around the environment and/or are only available to a parasite at specific times of the year. Finally, in many cases the environment that a single host can occupy is huge. With all of these difficulties facing parasites, it is not surprising that they have evolved many different strategies to effectively find hosts.

However, some species don’t appear to display these strategies. For them to succeed, it is possible that they distribute themselves in a non-random (see Did You Know?) fashion in the environment, clumping together to form “hot-spots” of infection. Other studies have investigated this “hot-spot” phenomenon before, but tended to focus on larger spatial scales, anywhere from hundreds to thousands of meters. Today’s authors wanted to understand if investigations at much smaller spatial scales (i.e., ~10 meters or less) could provide further insight into the spatial aggregation of parasites.

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The Red King Crab

The Red King Crab has been invading Norwegian waters over the last 50 years

Image Credit: Michelle Pemberton, The Children’s Museum of Indianapolis, CC BY-SA 3.0, Image Cropped

“… a red army of monster crustaceans – marshaled by Soviet-era leaders – is threatening to invade Western Europe …”

– James Owen, National Geographic, 2004

Ominous. That’s the thing, isn’t it. Some invasive species look harmless. You can’t be scared of a baby Canada Goose, can you? Or a nice purple garden flower. Such florescence. You can, however, be scared of a spiny, alien-looking 10 kilo mass of spines and pincers that has been shuffling its way into Norwegian waters over the last half-century.

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