Recently I've been doing a little reading into bothersome bugs as we have had quite a few club members being bitten whilst out running, blaming off road running initially, all that changed when we visited Horsfall track on Thursday and the pesky insects were out and biting again! It seems there's all sorts of theories on the subject as to why some people get bitten and others don't, particularly by mosquitoes which incidentally I have always associated with warmer climes and was shocked to learn there are over 35 species in the UK! Theory has it that all humans emit kairomones, common ones include C02 and lactic acid. It's thought that we all have our own kairomone signature which is probably unique to the individual in the same way as our fingerprints and different species prefer different kairomones just as some people prefer spicy and others don't! Very plausible since we 'gasp' half the time we are out running so must emit more carbon dioxide than most and also it's a known fact that lactic acid is produced whilst running.
From Wikipedia, the free encyclopedia
A kairomone is a semiochemical, emitted by an organism, which mediates interspecific interactions in a way that benefits an individual of another species which receives it, without benefiting the emitter. This "eavesdropping" is often disadvantageous to the producer (though other benefits of producing the substance may outweigh this cost, hence its persistence over evolutionary time). The kairomone improves the fitness of the recipient and in this respect differs from an allomone (which is the opposite: it benefits the producer and harms the receiver) and a synomone (which benefits both parties). The term is mostly used in the field of entomology (the study of insects). Two main ecological cues are provided by kairomones; they generally either indicate a food source for the receiver, or the presence of a predator, the latter of which is less common or at least less studied.