Mammals repel mosquitoes with their tails

Abstract

The swinging of a mammal's tail has long been thought to deter biting insects, which, in cows, can drain up to 0.3 liters of blood per day. How effective is a mammal's tail at repelling insects? In this combined experimental and theoretical study, we filmed horses, zebras, elephants, giraffes and dogs swinging their tails. The tail swings at triple the frequency of a gravity-driven pendulum, and requires 27 times more power input. Tails can also be used like a whip to directly strike at insects. This whip-like effect requires substantial torques from the base of the tail on the order of 10 1-10 2 N m, comparable to the torque of a sedan, but still within the physical limits of the mammal. Based on our findings, we designed and built a mammal tail simulator to simulate the swinging of the tail. The simulator generates mild breezes of 1 m s-1 , comparable to a mosquito's flight speed, and sufficient to deter up to 50% of mosquitoes from landing. This study may help us determine new mosquito-repelling strategies that do not depend on chemicals.

Understanding host utilization by mosquitoes: determinants, challenges and future directions

“…The intensity and efficiency of defensive behaviour is highly variable and largely dependent on host species, size, age, health status and individual behavioural type (Edman & Scott, 1987). For example, foot‐pecking and foot‐slapping are the most effective behaviours employed by birds to prevent mosquitoes from feeding on their legs (Webber & Edman, 1972), while mammals may use tail‐swatting and muscle‐twitching to repel blood‐sucking insects (Mooring et al ., 2007; Matherne et al ., 2018). Webber & Edman (1972) concluded that green herons ( Butorides virescens ) and black‐crowned night herons ( Nycticorax nycticorax ) performed fewer anti‐mosquito movements than other ciconiiforms and were bitten far more.…”

Visual threats reduce blood-feeding and trigger escape responses in Aedes aegypti mosquitoes

“…aegypti gauges the defensiveness of a host only after landing on it, it is worth highlighting that only visual cues were available in our experiments. But while mechanical cues (i.e., air displacement) generated by a mammal tail simulator significantly prevented mosquitoes from landing (Matherne et al, 2018), whether they can trigger the pre-biting resting behavior remains to be determined. In a previous study, when a mechanical vibration calibrated to mimic an average swat was repeatedly paired with host olfactory cues, Ae.…”

“…aegypti. However, mosquito species differ in their host preference, with some species biting smaller or larger mammals (Matherne et al, 2018), amphibians, or birds (Molaei et al, 2008), which vary drastically in their antiparasitic and defensive behaviors. As a consequence, it is likely that the tuning for certain ranges of object sizes, shapes, expansion rates, as well as linear and angular velocities will differ between mosquito species.…”

“…When approaching, the appendage induces rapid air displacement (i.e., mechanical component) and a rapid expansion of an object in the mosquito visual field (i.e., visual component). Using a mammalian tail simulator, Matherne et al, showed that the airflow generated by the swinging of mammals' tails reduced the proportion of Aedes aegypti landing by 50% (Matherne et al, 2018). In free flight, both Ae.…”

The squirrel is in the detail: Anatomy and morphometry of the tail in Sciuromorpha (Rodentia, Mammalia)

“…In many mammals, the tail fulfills a wide range of significant functions from balancing and steering during locomotion, to thermoregulatory functions and signaling as part of their behavioral repertoire (Bopp, 1954; Delgado & Jacobs, 2016; Dunbar & Badam, 2000; Emmons & Gentry, 1983; Fatjó et al, 2007; Hickman, 1979; Matherne et al, 2018; Schmitt et al, 2005; Stankowich, 2008; Thorington, 1966; Walker et al, 1998; Young et al, 2021).…”