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HorseAdvice.com » Horse Care » Routine Horse Care » Controlling Houseflies and Biting Flies » |
Discussion on Research Summary: Stripes and Attractiveness to Horseflies | |
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Moderator: DrO |
Posted on Sunday, Jul 14, 2013 - 8:36 am: Here is a fascinating study that shows that color and light patterns on the horse will effect their attractiveness to flies. Also new to me is that ammonia is attractive to the tabanid family of biting flies.DrO Physiol Behav. 2013 Jun 27. Stripes disrupt odour attractiveness to biting horseflies: Battle between ammonia, CO2, and colour pattern for dominance in the sensory systems of host-seeking tabanids. Blahó M, Egri A, Száz D, Kriska G, Akesson S, Horváth G. Environmental Optics Laboratory, Department of Biological Physics, Physical Institute, Eötvös University, H-1117 Budapest, Pázmány sétány 1, Hungary. Abstract As with mosquitoes, female tabanid flies search for mammalian hosts by visual and olfactory cues, because they require a blood meal before being able to produce and lay eggs. Polarotactic tabanid flies find striped or spotted patterns with intensity and/or polarization modulation visually less attractive than homogeneous white, brown or black targets. Thus, this reduced optical attractiveness to tabanids can be one of the functions of striped or spotty coat patterns in ungulates. Ungulates emit CO2 via their breath, while ammonia originates from their decaying urine. As host-seeking female tabanids are strongly attracted by CO2 and ammonia, the question arises as to whether the poor visual attractiveness of stripes and spots to tabanids is or is not overcome by olfactory attractiveness. To answer this question we performed two field experiments in which the attractiveness to tabanid flies of homogeneous white, black and black-and-white striped three-dimensional targets (spheres and cylinders) and horse models provided with CO2 and ammonia was studied. Since tabanids are positively polarotactic, i.e. attracted to strongly and linearly polarized light, we measured the reflection-polarization patterns of the test surfaces and demonstrated that these patterns were practically the same as those of real horses and zebras. We show here that striped targets are significantly less attractive to host-seeking female tabanids than homogeneous white or black targets, even when they emit tabanid-luring CO2 and ammonia. Although CO2 and ammonia increased the number of attracted tabanids, these chemicals did not overcome the weak visual attractiveness of stripes to host-seeking female tabanids. This result demonstrates the visual protection of striped coat patterns against attacks from blood-sucking dipterans, such as horseflies, known to transmit lethal diseases to ungulates. |
Member: paul303 |
Posted on Sunday, Jul 14, 2013 - 8:42 pm: Good heavens! So this could explain why my leopard app is so rarely bothered by flies (although sprayed), compared to my chestnut and sorrel QH mares. I always expected the app (with her pink skin)to be more of a target. |