Soft ticks perform evaporative cooling during blood-feeding

Abstract

<jats:title>Abstract</jats:title><jats:p>Feeding on the blood of warm-blooded vertebrates is associated to thermal stress in haematophagous arthropods. It has been demonstrated that blood-sucking insects protect their physiological integrity either by synthesising heat-shock proteins or by means of thermoregulatory mechanisms. In this work, we describe the first thermoregulatory mechanism in a tick species, <jats:italic>Ornithodoros rostratus</jats:italic>. By performing real-time infrared thermography during feeding on mice we found that this acarian eliminates big amounts of fluid (urine) through their coxal glands; this fluid quickly spreads over the cuticular surface and its evaporation cools-down the body of the tick. The spread of the fluid is possible thanks to capillary diffusion through the sculptured exoskeleton of <jats:italic>Ornithodoros</jats:italic>. We discuss our findings in the frame of the adaptive strategies to cope with the thermal stress experienced by blood-sucking arthropods at each feeding event warm-blooded hosts.</jats:p>

Beat the heat:Culex quinquefasciatusregulates its body temperature during blood-feeding

“…Another strategy, evaporative cooling, consists of excreting and retaining droplets of fluid in order to cool down (Heinrich, 1980a;Prange, 1996). Several hematophagous arthropods, including sandflies (Sadlova et al, 2013), mosquitoes (Lahondère and Lazzari, 2012) and ticks (Lazzari et al, 2020), use this method to cool down during blood intake. Mosquitoes use prediuresis droplets for evaporative cooling, in which the insect excretes a droplet composed of fresh blood and urine and holds it at the tip of the abdomen to cool down (Lahondère and Lazzari, 2012).…”