Mosquitoes

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Mosquitoes Wetlands

• Prepared by Kelly V. Tindall
• Extension Entomologist
• Twin Falls County

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• Mosquito Biology
• Wetlands mosquito habitat
• Natural
• Artificial

Silver Creek, near Picabo
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Mosquito Life Cycle
Adults emerge
Eggs (100-250/egg laying event)
10 times a year
Pupae
Overwinter all stages (species dependent) Egg to
Adult some species 4-5 days Adults live up to 2
wks
Larvae
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Mosquito Facts

• Only females bite (bloodmeal)
• Males feed on nectar
• Larvae feed on algae, etc.
• 200 species in the US
• 43 species are WNV vectors
• As many as 51 species in ID
• Of the 20 most common in ID 10 are WNV vectors

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Mosquito Facts

• Some lay eggs in the soil
• Flood is required for them to mature (floodwater
  mosquitoes)
• Must remain moist to complete development
• Differences in water quality
• Some clean water, some polluted

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How Does This Tie in to Wetlands?
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Wetlands

• Areas where water covers soil or near the surface
  of soil all year or for varying time(s) of the
  year
• Types of natural wetlands
• Marine (coastal, salt water)
• Estuarine (coastal, salt/freshwater mix)
• Riverine (associated with rivers stream)
• Lacustine (associated with lakes)
• Palustrine (misc. freshwater wetlands)

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Riverine Wetlands Riparian Area

• Along streams, rivers irrigation canals
• Healthy river system is important
• Support vegetation, including trees, shrubs
  grass
• Prevent erosion
• Habitat for many animals
• Riparian areas 1 land,
• BUT 80 of animals utilize

Snake River
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Lacustine

• Perimeter of lakes and reservoirs
• 20 acres OR
• Water 6 ft in depth
• Exposed to wave action

Dierkes Lake
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Palustrine

• Smaller and shallower than wetlands around lakes
• Forest wetlands
• Bitterroot Mtns.
• Cooler air
• More understory
• Hot springs
• Vernal pools

Gospel Hump
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Artificial Wetlands

• Retention ponds, etc.
• Many are shallow dense vegetation
• Can provide wildlife habitat also

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Do Wetlands breed Mosquitoes?

• It depends!
• Are they healthy? NO
• Are they mismanaged? possibly
• Artificial wetlands likely

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Healthy vs Unhealthy Wetlands
Unhealthy NO vegetation, ground trampled
Salmon Falls Canyon
Standing water is prime breeding ground
Healthy trees, shrubs, grasses
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What makes some areas less likely to breed
mosquitoes?

• Sparse vegetation
• Less area to hide from predators
• Reduced food source
• Windy conditions
• Interferes with egg laying
• Causes problems with breathing
• Water quality
• Good water ? predators

HEALTHY WETLANDS
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Biological Control for Adults
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Biological Control for Larvae
Predacaeous diving beetle
Backswimmers
Dragonfly Damselfly larvae
Water Striders
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Wetlands Reduce Mosquitoes by

• Providing habitat for the natural enemies
• Preventing/reducing flooding
• Wetlands store excess water until in can be
  absorbed and recharge aquifers and other water
  sources
• How effective are wetlands for mosquito control?
• Essex County Mosquito Control Project (MA)
  restored a 1,500 acre
• Mosquito population dropped by 90.

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What makes some areas more likely to breed
mosquitoes?

• Dense vegetation
• Area to hide from predators
• Vegetation hinders pesticide contact
• Hinder water flow (irrigation canals)
• Water quality / Water level
• Poor quality preferred by mosquitoes AND bad
  for predators

UNHEALTHY WETLANDS
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Polluted Waters
Animal poo/decomposing animals in water ?
organic matter ? low predator populations ?
low dissolved oxygen ? mosquitoes
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Why Protect Wetlands?

• Drained/mismanaged wetlands mosquito "blooms"
  after rain/irrigation
• Restore or create a healthy wetlands
• Natural predators will begin to return
• You reduce mosquitoes and GAIN
• Wildlife habitat
• Reduced chanced of flooding on adjacent ground
• Improving water quality

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How to Protect

• Vegetation Management
• Restoration plant specific native plants
• Remove dead foliage
• Limited access
• Minimize large animals from grazing trampling
• Reduce ATV usage

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Cross Section of Artificial Wetland Designed to
Reduce Mosquitoes
Vertical Side