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It helps to have hairy legs when there are mosquitoes or ants around.
According to new research, being hairy is a good thing, if you don’t want to be bitten by a mossy that is. Apparently, having lots of body hair makes it harder for biting insects such as mosquitos and ants to get a good chomp of you. It also increases the chance of you noticing the bugs before they do any damage.
https://www.joe.ie/uncategorized/hairy-men-less-likely-to-be-bitten-by-insects-30223
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*The article is at least 10 years old.
NIH
Biol Lett. 2012 Jun 23; 8(3): 358–361.
Published online 2011 Dec 14. doi: 10.1098/rsbl.2011.0987
PMCID: PMC3367735
PMID: 22171023
Human fine body hair enhances ectoparasite detection
Isabelle Dean and Michael T. Siva-Jothy*
Abstract
Although we are relatively naked in comparison with other primates, the human body is covered in a layer of fine hair (vellus and terminal hair) at a relatively high follicular density. There are relatively few explanations for the evolutionary maintenance of this type of human hair. Here, we experimentally test the hypothesis that human fine body hair plays a defensive function against ectoparasites (bed bugs). Our results show that fine body hair enhances the detection of ectoparasites through the combined effects of (i) increasing the parasite’s search time and (ii) enhancing its detection.
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2. Material and methods
(a) Hosts
Twenty-nine student volunteers in the University of Sheffield (10 females and 19 males) were recruited through opportunity sampling on the social networking site, Facebook. They were aged between 19 and 27 years (median age 21 years). All participants were made aware of the risk of being bitten (no volunteers were bitten during the course of this study) and the potential risks of adverse dermatological reactions if they were bitten [14]. Each volunteer was assigned an identifying number and all data collected were anonymized with respect to host. We followed the University of Sheffield ethics regulations [15] throughout.
(b) Parasites
The bed bugs used in this study originated from recently (2007) field-collected populations that have retained natural behaviours despite being reared in the laboratory. We used only imaginal females in this study. All were fed to satiation using standard protocols [11] exactly a week before a trial took place. This time frame matches C. lectularius natural feeding habits [11,16] and ensured all experimental bed bugs were (i) ready to feed and (ii) of similar ‘hunger’ status. Bed bugs which did not attempt to feed were excluded from the data. Because each host was tested twice, and because we wanted to use the same five bed bugs at each host’s test, we gave each bed bug a unique acrylic paint spot at the back of its abdomen (applied with the tip of a wooden cocktail stick).
4. Discussion
Our results show that the presence of fine body hair (i) prolongs the search behaviour of C. lectularius and (ii) enhances the detection of searching ectoparasites. Moreover, a higher hair index makes a host more likely to detect an ectoparasite. Because males have a higher hair index compared with females this result has implications for sex-differences in parasite detection. Unfortunately, we could not distinguish between vellus hair and terminal hair in our study and sexual dimorphism in terminal hairs may be partly responsible for the higher hair index in males in this study. Enhanced male detection of ectoparasites may be an evolutionary response driven by female mate choice directed at parasite-free males [17] and/or sexual dimorphism in investment in immune function [18].
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Our data suggest that reduced body hair in humans functions, at least partly, as a defence against ectoparasites. On the basis of our results, and our conclusion that fine body hair functions to enhance ectoparasite detection, we predict that transient ectoparasites should show feeding preferences for relatively hairless parts of their host’s body.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3367735/
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weehingthong 