New Dauin/Philippines Invertebrate Footage

[klausi]

New Dauin Underwater Footage

Since coming back to the Philippines in December of last year I have had the pleasure to do a few interesting dives with a camera.

During a night dive in Zamboanguita, just south of Dauin, I encountered a mantis shrimp. It was running around outside of its burrow, which is somewhat rare, but on top of that it was absolutely enormous. This seems to be one of Lysiosquillina maculata, the tiger/banded mantis shrimp, which is the biggest species of mantis shrimp know, and it must have been an individual close to the max size, ~ 40 cm:


During another night dive I caught a pair of crabs fighting. Crabs have a very emotional inner life: when faced with humans, they are very fearful, but against each other they can be very aggressive. These two fought over a territory, the base of an anemone. The fighting style is most closely related to wrestling it seems:

 

[Sure Squintsalot]

There's piles of research on mantis shrimp from questions regarding their vision to their "punch" and defenses against other shrimps punches. One of the things that utterly fascinates me is their capacity for semaphore communication between individuals. A friend, now a professor at Brown University has studied, among other things, how mantis shrimps fight for new burrows in the context of resource assessment:

Resource value assessment, in which competitors adjust behaviours according to the perceived value of a contested resource, is well described in animal contests. Such assessment is usually assumed to be categorical or linear; for example, males fight more aggressively when females are present than absent, or as female fecundity increases. Here, to our knowledge for the first time, we show quadratic resource value assessment, in which resource value is highest at a certain level and decreases in either direction. The mantis shrimp Neogonodactylus bredini occupies coral rubble burrows in a size-assortative manner: individuals of a certain body size inhabit burrows of a certain size. Using mock burrows of various sizes, we tested whether mantis shrimp (1) chose burrows predicted to be the best fit for their body size and (2) were more aggressive during, endured higher costs during and were more likely to win contests over burrows predicted to be best fit.

There's no end to how amazing these things are!

 

[BoltSnap]

Brilliant!! I enjoyed watching both videos. Thank you for sharing!!

 

[klausi]

There's piles of research on mantis shrimp from questions regarding their vision to their "punch" and defenses against other shrimps punches. One of the things that utterly fascinates me is their capacity for semaphore communication between individuals. A friend, now a professor at Brown University has studied, among other things, how mantis shrimps fight for new burrows in the context of resource assessment:

Resource value assessment, in which competitors adjust behaviours according to the perceived value of a contested resource, is well described in animal contests. Such assessment is usually assumed to be categorical or linear; for example, males fight more aggressively when females are present than absent, or as female fecundity increases. Here, to our knowledge for the first time, we show quadratic resource value assessment, in which resource value is highest at a certain level and decreases in either direction. The mantis shrimp Neogonodactylus bredini occupies coral rubble burrows in a size-assortative manner: individuals of a certain body size inhabit burrows of a certain size. Using mock burrows of various sizes, we tested whether mantis shrimp (1) chose burrows predicted to be the best fit for their body size and (2) were more aggressive during, endured higher costs during and were more likely to win contests over burrows predicted to be best fit.

There's no end to how amazing these things are!

Good stuff, thanks for sharing. These kinds of optimization tasks are often surprisingly well solved by animals which humans think of as "only" an invertebrate.