Nymphs of blood-sucking ticks cooled own urine

So as not to overheat in the absorption of warm blood nymph ticks Ornithodoros rostratus cooled by its own liquid secretions. Evaporating from the surface of the body of arachnids, the fluid reduces its temperature by three degrees Celsius. As noted in a Preprint published on bioRxiv, this is the first example of thermoregulation ticks.

Many invertebrates feed exclusively on the blood of warm-blooded animals — mammals and birds. This diet is connected with several difficulties: for example, the absorption of large quantities of hot blood can cause heat stress. To avoid it, some insects rely on heat shock proteins, and enhanced thermoregulation. However, until now it was unclear how to cope with this threat, the representatives of the other rich bloodsuckers of the band — clamp.

To understand this issue decided by a team of researchers led by Claudio Lazzari (Claudio R. Lazzari) of tours University. As a model of the object they chose a South American ticks, Ornithodoros rostratus ergashovich of the family (Argasidae), which are parasitic on humans and other large mammals. The bites of these invertebrates is very painful, and they carry various diseases.

Scientists made the tick nymphs to fast for 20-30 days. Then the experimental animals were placed on the body of anesthetized hairless mice and removed the feeding process for a thermographic camera.

Researchers noticed that eight minutes after the suction on the lower body O. rostratus appeared a drop of liquid, which gradually increased in size until the end of the feeding. Its source was coxalgia glands — excretory organs of arachnids, located in the cephalothorax. Simply put, nymph ticks were cooled own urine.

Once on the host’s body, rapidly heated mites: their body temperature reached 34 to 35 degrees Celsius. Once you start feeding it remained the same or increased slightly. However, due to the isolation and evaporation of the liquid of the ticks to the moment of saturation could be cooled by three degrees Celsius.

To understand the mechanics of this process, the researchers applied to the surface of a body of five individuals drop fluorescent solution. It turned out that the complex microstructure of the integument of ticks, including many pits and grooves, allows liquids to be evenly distributed throughout the body, which increases the cooling effect of evaporation.

The authors emphasize that this is the first known mechanism of thermoregulation ticks. Possible similar adaptation, and there are other types of these creatures in the first place from the blood-sucking.

Blood-sucking mites have plagued the dinosaurs. About this is evidenced by the discovery in Burmese amber age 99 million years: a tick next to the dinosaur pen. New look has received a resounding name of the Deinocroton draculi, “terrible mite Dracula.”

Sergey Knee High

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