Mosquito Studies
ES students have been involved in two different mosquito studies. The first started with a review of why some people are more frequently bitten than others. The second dealt with the effectiveness of the biological controls used in Whitehorse.
Researchers have speculated why some people are targeted by mosquitoes. About 20% of the population get bit more often on a consistent basis. Scientists have a number of ideas regarding why some of us are more prone to bites than others. Here are some of the factors that are hypothesized to play a role:
In 2006-7 as part of a study in life cycle and behavior of mosquitoes, an ES class explored the reasons for selective attractiveness of individuals to mosquito bites. While on forestry field studies students counted bites on individuals by examining three factors: colour of clothes, size of the person and bites following exercise. Students cataloged cloths colours, body weight and half the class ran then exposed skin compared to the others that sat quietly. All students exposed a fore arm for 20 minutes and counted bites following the exposure. Results were a bit inconclusive. Only the exercise seemed to affect mosquito selection.
The second study was conducted by two individuals that set out large horse buckets with water and counted mosquito larval found in the water between May 20 and June 15> One bucket was in Riverdale and the other was Robinson, in Mt Loren, outside the mosquito control area.
Larval surveying and monitoring for the City of Whitehorse is typically conducted in the early spring, conditions permitting. April 2015, depending on conditions. The goal of the annual control program is to reduce adult mosquito annoyance for residents and visitors. Experience has proven that the best way to achieve this is through effective control of larval mosquito populations. Control of larval mosquito populations will be completed as required, and where necessary, throughout the season on the basis of mosquito population surveillance. Larvicide applications will be made using aerial (helicopter) and groundbased, hand-broadcast methods. The control program is focused on the identification and treatment of developing mosquito larvae using the biological larvicide VectoBac 200G which contains the heat-killed bacterium, Bacillus thuringiensis var. isrealensis (Bti). This bacterium is specific in its control of mosquitoes and biting flies. It does not reproduce in the environment and has no effect on non-target insects, fish birds or mammals, including humans, livestock and pets. All applications will be directed to infested mosquito development habitat located within, and adjacent to, the City of Whitehorse.
We found a dramatic difference in the larval populations with only 2 found in Rverdale and 27 found in the Robinson sample. This survey will need to be repeated a number of times to be considered valid.
ES students have been involved in two different mosquito studies. The first started with a review of why some people are more frequently bitten than others. The second dealt with the effectiveness of the biological controls used in Whitehorse.
Researchers have speculated why some people are targeted by mosquitoes. About 20% of the population get bit more often on a consistent basis. Scientists have a number of ideas regarding why some of us are more prone to bites than others. Here are some of the factors that are hypothesized to play a role:
- Certain blood types get more bites than others. People with Type O blood nearly twice as often as those with Type A. People with Type B blood fell somewhere in the middle of the spectrum.
- Mosquitoes locate their targets is by smelling the carbon dioxide emitted in their breath. People who exhale more of the gas over time—generally, larger people—attract more mosquitoes than others.
- Mosquitoes find victims at closer range by smelling the lactic acid, uric acid, ammonia and other substances expelled via their sweat, and are also attracted to people with higher body temperatures. Strenuous exercise increases the buildup of lactic acid and heat in your body and therefore attracts more bites.
- Large amounts of a few types of bacteria made skin more appealing to mosquitoes. But greater diversity of bacteria seemed to make skin less attractive.
- A bottle of beer can makes an individual more attractive to the mosquitoes.
- Mosquitoes also use vision to locate humans, so wearing colors that stand out (black, dark blue or red) make you easier to find.
- Underlying genetic factors are estimated to account for 85 percent of the variability between people in their attractiveness to mosquitoes
In 2006-7 as part of a study in life cycle and behavior of mosquitoes, an ES class explored the reasons for selective attractiveness of individuals to mosquito bites. While on forestry field studies students counted bites on individuals by examining three factors: colour of clothes, size of the person and bites following exercise. Students cataloged cloths colours, body weight and half the class ran then exposed skin compared to the others that sat quietly. All students exposed a fore arm for 20 minutes and counted bites following the exposure. Results were a bit inconclusive. Only the exercise seemed to affect mosquito selection.
The second study was conducted by two individuals that set out large horse buckets with water and counted mosquito larval found in the water between May 20 and June 15> One bucket was in Riverdale and the other was Robinson, in Mt Loren, outside the mosquito control area.
Larval surveying and monitoring for the City of Whitehorse is typically conducted in the early spring, conditions permitting. April 2015, depending on conditions. The goal of the annual control program is to reduce adult mosquito annoyance for residents and visitors. Experience has proven that the best way to achieve this is through effective control of larval mosquito populations. Control of larval mosquito populations will be completed as required, and where necessary, throughout the season on the basis of mosquito population surveillance. Larvicide applications will be made using aerial (helicopter) and groundbased, hand-broadcast methods. The control program is focused on the identification and treatment of developing mosquito larvae using the biological larvicide VectoBac 200G which contains the heat-killed bacterium, Bacillus thuringiensis var. isrealensis (Bti). This bacterium is specific in its control of mosquitoes and biting flies. It does not reproduce in the environment and has no effect on non-target insects, fish birds or mammals, including humans, livestock and pets. All applications will be directed to infested mosquito development habitat located within, and adjacent to, the City of Whitehorse.
We found a dramatic difference in the larval populations with only 2 found in Rverdale and 27 found in the Robinson sample. This survey will need to be repeated a number of times to be considered valid.