Why does genetic variation increase the chance that some individuals in a population will survive? Genetically diverse populations display high phenotypic variation. If changing environmental conditions favor a particular phenotype there is a good chance that genetically diverse population will have some individuals who have that advantageous phenotype.
As well, the candles produce large particles in their smoke and there have been concerns about how safe it is to regularly breathe in this smoke. Mosquito coils: Like citronella candles, mosquito coils produce a smoke that confuses mosquitoes. The coils contain the insecticide allethrin.
Citronella oil is an ingredient in some mosquito repellents you can buy at the store. It seems to prevent mosquito bites for a short amount of time, typically less than 20 minutes. Other mosquito repellents, such as those containing DEET, are usually preferred because these repellents last much longer.