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2CIBIO
Research Centre in Biodiversity and Genetic Resources, InBIO,
Universidade do Porto, Campus Agrário de Vairão, 4485-661
Vairão, Vila do Conde, Portugal. |
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Scorpion
venom is a complex mixture of toxins. A lot of work is being
done on the biochemical properties of the scorpion venom and not
that much of work has yet been performed on the bioechanical
aspects of scorpion venom delivery. The amount of venom released
during different stings is known to be different. Scorpions,
just like snakes and spiders, have the ability to meter the
amount of venom they want to expel. Production is an expensive
metabolic investment. In scorpions metabolic rate gets up to
39%, for milked specimens compared to the unmilked ones. Factors
like the amount of total venom present in the scorpion's venom
glands at that moment and the perceived level of threat to the
scorpion, can influence in order to test its influence on the
volume of released venom. Hadrurus arizonensis, was the
species chosen for the experiment. Two hypothesis where formed.
The first one defends that scorpions are able to meter the
amount of venom they expel. The second one states that larger
quantities of venom are expected to be released by the
scorpions, as the level of threat increases. Our results show
that during ten consecutive attacks to which scorpions were
exposed in rapid succesión, venom volume released on each attack
is being controlled by the scorpion, changing the amount of
released venom between the attacks. Overall, the amount of venom
released on consecutive attacks decreases, but there is high
inter-individual variability. The number of dry stings, where no
venom is released whatsoever, increases with the number of
consecutive threats, and also varies by individual. By the end,
we did accept the first hypothesis, and reject the second one. |
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