Spearer
mantis shrimps use a much slower hunting method than smasher mantis
shrimp, relying on muscle power instead of stored energy.
While
smasher shrimps actively hunt their prey, spearers are ambush
predators. They wait for a morsel to appear overhead and then strike it
with one lightning-fast movement. Since ambush hunters have a smaller
time in which to strike, as well as faster prey than sm
ashers, it was expected that spearers would have the faster mechanism.
However, when Maya deVries and her team (University of Berkeley, USA)
examined spearers and smashers, it became clear smashers strike much
faster. While smashers can strike at speeds reaching 23 metres per
second, the two spearer species examined (Alachosquilla vicina and
Lysiosquillina maculata) could only reach 5.7m and 2.3m per second
respectively.
The explanations for these differences lay in
the mechanisms each type uses to hunt. Smasher mantis shrimps are able
to deliver a devastating punch to their prey - powerful enough to
destroy a crustacean's shell or break aquarium glass - because of the
"spring" mechanism they use. To ready a punch, they bring their arm back
and locks it in place, building energy for its blow. A. vicina uses a
similar spring-loaded method to spear, explaining why it is faster than
L. maculata (which just uses muscle). Interestingly L. maculata has the
same anatomical "catch" as A. vicina - it just doesn't use it. It never
engages the spring.
Several explanations are being suggested as
an explanation for this difference. L. maculata's size could be an
issue - it is the largest mantis shrimp, and there may be a size limit
on spring-loaded mechanisms. It could be spearers just don't need to be
as fast, and that speed is far more key for an impact attack than a
sharp "harpoon" strike. A spearer relies on a single strike, whereas a
smasher may need multiple punches. deVries and her team are trying to
gather more L. maculata in the lab to investigate.
Photo credit: Roy Caldwell, UC Berkeley.
http://jeb.biologists.org/
http://
http://jeb.biologists.org/
http://www.redorbit.com/news/
Spearer
mantis shrimps use a much slower hunting method than smasher mantis
shrimp, relying on muscle power instead of stored energy.
While smasher shrimps actively hunt their prey, spearers are ambush predators. They wait for a morsel to appear overhead and then strike it with one lightning-fast movement. Since ambush hunters have a smaller time in which to strike, as well as faster prey than sm
While smasher shrimps actively hunt their prey, spearers are ambush predators. They wait for a morsel to appear overhead and then strike it with one lightning-fast movement. Since ambush hunters have a smaller time in which to strike, as well as faster prey than sm
ashers, it was expected that spearers would have the faster mechanism.
However, when Maya deVries and her team (University of Berkeley, USA) examined spearers and smashers, it became clear smashers strike much faster. While smashers can strike at speeds reaching 23 metres per second, the two spearer species examined (Alachosquilla vicina and Lysiosquillina maculata) could only reach 5.7m and 2.3m per second respectively.
The explanations for these differences lay in the mechanisms each type uses to hunt. Smasher mantis shrimps are able to deliver a devastating punch to their prey - powerful enough to destroy a crustacean's shell or break aquarium glass - because of the "spring" mechanism they use. To ready a punch, they bring their arm back and locks it in place, building energy for its blow. A. vicina uses a similar spring-loaded method to spear, explaining why it is faster than L. maculata (which just uses muscle). Interestingly L. maculata has the same anatomical "catch" as A. vicina - it just doesn't use it. It never engages the spring.
Several explanations are being suggested as an explanation for this difference. L. maculata's size could be an issue - it is the largest mantis shrimp, and there may be a size limit on spring-loaded mechanisms. It could be spearers just don't need to be as fast, and that speed is far more key for an impact attack than a sharp "harpoon" strike. A spearer relies on a single strike, whereas a smasher may need multiple punches. deVries and her team are trying to gather more L. maculata in the lab to investigate.
Photo credit: Roy Caldwell, UC Berkeley.
http://jeb.biologists.org/
http://
http://jeb.biologists.org/
http://www.redorbit.com/news/
However, when Maya deVries and her team (University of Berkeley, USA) examined spearers and smashers, it became clear smashers strike much faster. While smashers can strike at speeds reaching 23 metres per second, the two spearer species examined (Alachosquilla vicina and Lysiosquillina maculata) could only reach 5.7m and 2.3m per second respectively.
The explanations for these differences lay in the mechanisms each type uses to hunt. Smasher mantis shrimps are able to deliver a devastating punch to their prey - powerful enough to destroy a crustacean's shell or break aquarium glass - because of the "spring" mechanism they use. To ready a punch, they bring their arm back and locks it in place, building energy for its blow. A. vicina uses a similar spring-loaded method to spear, explaining why it is faster than L. maculata (which just uses muscle). Interestingly L. maculata has the same anatomical "catch" as A. vicina - it just doesn't use it. It never engages the spring.
Several explanations are being suggested as an explanation for this difference. L. maculata's size could be an issue - it is the largest mantis shrimp, and there may be a size limit on spring-loaded mechanisms. It could be spearers just don't need to be as fast, and that speed is far more key for an impact attack than a sharp "harpoon" strike. A spearer relies on a single strike, whereas a smasher may need multiple punches. deVries and her team are trying to gather more L. maculata in the lab to investigate.
Photo credit: Roy Caldwell, UC Berkeley.
http://jeb.biologists.org/
http://
http://jeb.biologists.org/
http://www.redorbit.com/news/
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