There are
no effective avian, mammalian, amphibian, reptilian, or insect predators that
will provide natural or biological control of mosquito populations. There are
species of these predators that will feed on mosquito larvae and adults but not
to the extent that they will control the population.
Avian
Predators
There are
no bird species that are effective at controlling mosquito populations; Tree
swallows are the most effective and adult and juvenile waterfowl species and
migratory songbirds will eat larvae and may be dependent on them at certain times of the year. Purple martins eat insignificant numbers
of mosquitoes.
Mammalian Predators
Bats play
an important role in the environment and can serve as agricultural pest control
agents but they are not effective as mosquito control agents. They will eat 500
to 1200 insects/hour. There are no bat species that specialize in eating
mosquitoes but there are bat species that have a portion of their diet
consisting of mosquitoes (Big Brown Bat-nearly 0%, Little Brown Bat-much more
likely to feed on mosquitoes). Due to their high metabolic rate, Big Brown Bats
don't select mosquitoes as a food source. Mosquitoes don't swarm, they provide
small amounts of energy, and they are more likely to be found in vegetation, not
in areas where the bats will be feeding.
The Big
Brown Bat is the most common bat in Michigan and their diet primarily consists
of June beetles, moths, ground beetles, and stink bugs. The Little Brown Bat,
which commonly occurs In the northern part of the state, has a diet that
primarily consists of spiders, mosquitoes, and dipterous insects
Inhabitants of bat houses in residential areas will have minimal impact on
mosquito populations, especially in the southern portion of the state where the
Big Brown Bat is the most common species to utilize a bat house. Little Brown
Bats (much less common in the southern portion of the state) will have a minor
impact on the mosquito population as mosquitoes make up a small percentage of
their diet. If bat houses are placed in residential areas, they likely will
provide an alternative roosting area of bats already present. It is important
to erect the house in a proper location (15 feet in the air, in direct sunlight
for no more than 4 to 6 hours, and not attached to a residence). Big Brown Bats
are the main species in Michigan to be diagnosed with rabies (it is estimated
that less than 1% of the bats in the state are rabid). Because of this, it is
important to avoid contact with bats that are found on the ground, outside of a
bat house, or during daylight hours. If dead bats are found and there has been
no known pet or human exposure, they should be collected by picking them up with
a shovel, placing them in a plastic bag, and disposing of them properly.
Amphibian and Reptilian Predators
There are
no amphibians or reptiles that are effective at mosquito control. The cricket
frog, Chorus frog, and Spring peeper will eat mosquitoes but won't impact a
population.
Insect
Predators
Dragonfly
larvae and aquatic beetles will feed on mosquito larvae, but won't control the
population.
Pesticide Usage Impact
If
pesticides are used, Larvicide and Adulticide compounds are the options
available. Larvicide use, which targets mosquitoes during their aquatic stage,
is viewed as the least damaging to non-target wildlife in the application area.
Adulticide use is considered more harmful to the wildlife present. General
insecticide use, especially of organophosphate compounds could eliminate many
species of insects and their removal as a prey base could impact avian,
amphibian, reptilian, and insect populations.