Abstract
During blood-sucking, female members of the family Tabanidae transmit pathogens of serious diseases and annoy their host animals so strongly that they cannot graze, thus the health of the hosts is drastically reduced. Consequently, a tabanid-resistant coat with appropriate brightness, colour and pattern is advantageous for the host. Spotty coats are widespread among mammals, especially in cattle (Bos primigenius). In field experiments we studied the influence of the size and number of spots on the attractiveness of test surfaces to tabanids that are attracted to linearly polarized light. We measured the reflection-polarization characteristics of living cattle, spotty cattle coats and the used test surfaces. We show here that the smaller and the more numerous the spots, the less attractive the target (host) is to tabanids. We demonstrate that the attractiveness of spotty patterns to tabanids is also reduced if the target exhibits spottiness only in the angle of polarization pattern, while being homogeneous grey with a constant high degree of polarization. Tabanid flies respond strongly to linearly polarized light, and we show that bright and dark parts of cattle coats reflect light with different degrees and angles of polarization that in combination with dark spots on a bright coat surface disrupt the attractiveness to tabanids. This could be one of the possible evolutionary benefits that explains why spotty coat patterns are so widespread in mammals, especially in ungulates, many species of which are tabanid hosts.
Highlights
The coat pattern of cattle (Bos primigenius) has a remarkably large diversity ranging from homogeneous black and brown, through brown-white or black-white spotty, to homogeneous grey or white
At a given background the coat pattern influences the visual detectability such that a spotty coat makes the animal conspicuous against a homogeneous background, but can endow with camouflaging at a structured background, for instance, similar to what has been shown by a classical experiment in the moth Biston betularia [3,4]
For both vertical and horizontal test surfaces the number N of trapped tabanids decreased with increasing number and decreasing size of the brown spots: the white vertical test surfaces with 1, 4, 16 and 64 spots captured 67.1%, 31.5%, 1.1% and 0.3% of all tabanids trapped in this experiment, while the same data for the horizontal spotty surfaces were 47.9%, 38.5%, 7.7% and 5.9% (Supplementary Table S1)
Summary
The coat pattern of cattle (Bos primigenius) has a remarkably large diversity ranging from homogeneous black and brown, through brown-white or black-white spotty, to homogeneous grey or white. These coat patterns are specific to species and races, and are the result of domestic breeding. Colour and spottiness of the coat in cattle and horses are usually of marginal importance and are the by-product of cross-breeding aiming to maximize other economically more important characteristics of the animal, e.g. the milk or meat production, weather-proofness, or the shape or size of the animals
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
