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'Count Dracula' still sucks blood as a spider

     Washington: Count Dracula lives again, if not in real humans, then certainly in other life forms. Researchers claimed to have found a small East African jumping spider that has a taste for blood. The spider, Evarcha culicivora, lacks the ability to pierce skin and to sip blood, and for filling its bloody thirst, preys on female mosquitoes, who have just had their fair share of human blood. Researchers have said that this is first time they have come across a predator that chooses its prey on the basis of what it (prey) ate. "Perhaps blood is a ready-made nutrient-rich liquid meal for which minimal energy expenditure in terms of processing is needed," Discovery News quoted Ximena Nelson, lead author of the study, published in the Proceedings of the National Academy of Sciences, as saying. For tests, Nelson and her team placed the spider in a glass vial so that it could not smell prey choices, which included a combination of male mosquitoes that do not consume blood, female mosquitoes that were fed a sugar concoction and female mosquitoes that had just feasted on blood.

    The findings revealed that using sight alone, the spider always chose the blood-engorged females, that looked fat and somewhat red. Further tests where the spider had to rely on its weak sense of smell also revealed that the it went for females that had just dined on blood. Nelson said that feeding on blood is a dangerous activity, and the spider by preying on female mosquitoes was only minimizing its risk. "Animals that are bitten have a reflective 'swatting' response - humans use their arms, tailed animals use their tails, etc.- and often the insect is killed. It may be safer for Evarcha to obtain blood by killing a mosquito, then risk being swatted, even if they did have the mouth parts required to pierce skin and locate a blood vessel," she added. The spider also uses a rather clever technique for catching its fat female mosquitoes. It stalks the mosquito like a cat, and then pounces either on top or underneath the mosquito before taking a bite. "They hold them close to their face, not forward projecting as mosquitoes do. Perhaps they might stab themselves, and this would kill them as spiders rely on a high hydrostatic pressure inside their bodies to 'hold them up," she further said.

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