Snow Pool Mosquito Habitat

Snow Pool Habitats – High Point State Park

Among the first mosquito larvae to hatch in NJ are those inhabiting the state’s snow pools found in the high elevations of Stokes State Forest and High Point State Park in the states Valley and Ridge physiographic province with peak elevations ranging from 1,600-1,800 feet. The gravitational force at these high elevations is lower resulting in less atmosphere which in turn decreases the scattering of light making the sky appear darker blue like brilliant sapphire or English blue topaz. The less dense air also results in colder temperatures because there is not as much atmosphere to hold the heat in as in lower elevations.

The snow pool mosquitoes that thrive in these chilly late winter to early-spring habitats are found in relatively deep woodland pools darkened by the tannin of oak leaves lining the bottom of the pools. While some larvae can be found in the more shallow pools, collecting often involves wearing chest waders and carefully moving through steep sided deep pools. Among the first species to hatch are Aedes communis and Ae. provocans, and you can find 4th instar larvae of these species in mid to late march in High Point State Park. You can also find Ae. stimulans and Ae. excrucians in the same habitat in mid to late March, but they will usually be a couple of instars behind. As the spring progresses the deep snow pools dry down, and the other woodland pools in the area serve as prime habitat for some of the other later season univoltine Aedes like Ae. canadensis, Ae. cinerius, Ae. sticticus, and Ae. abserratus.

The video below demonstrates the method of scanning for Ae. communis larvae in High Point NJ’s deep snow pools. This involves moving your mosquito dipper about a foot below the water’s surface and letting the dark colored larvae stand out against the white of the dipper. Often these larvae will dive into the white colored dipper, in essence collecting themselves for you!

 

 

 

 

 

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As you near the peak elevations in NJ the lower atmospheric pressure results in a darker blue sky that fades to a brilliant light blue towards the horizon. Photo Credit: Dr. Diana Carle
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The dark English blue topaz colored sky over the snow pool sites at High Point. Photo Credit: Dr. Diana Carle
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Typical snow pool mosquito habitat typified by high elevation, cold water, dark tannin rich water from fallen oak leaves. This is near the end of March when the snow pool mosquitoes can be found pupating and in 4th instar, just  few weeks prior snow is usually still present when sampling the habitats.  Photo credit: Dr. Diana Carle
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Many pristine streams run through this high mountain landscape and while they don’t harbor mosquitoes, other rare insects can be found within. Photo Credit: Dr. Diana Carle
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The snow pools that harbor Ae. communis are often dark, steep sided, and deep and require chest waders to effectively sample. Photo credit: Dr. Diana Carle
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Even the shallower oak stained pools can be abundant with snow pool mosquitoes. Photo credit: Dr. Diana Carle
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Dipping for Ae. communis and Ae. provocans in the snow pools of High Point in March you will also find Machlonyx midge larvae which are indicators of the specific type of habitats in which you find snow pool mosquitoes. Photo Credit: Dr. Diana Carle
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Fairy shrimp are commonly found associated with Ae. communis larvae, and are a good indicator that you are dipping the right habitat. Photo credit: Dr. Diana Carle
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Sexual dimorphism in fairy shrimp female (left) and male (right). Photo credit: Dr. Diana Carle
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These shallower woodland pools at High Point were producing 2nd and 3rd instar Ae. canadensis and Ae. stimulans at the same time Ae. communis and Ae. provocans 4th instar larvae and pupae were being collected from the deep snow pools near the end of March. Photo Credit: Dr. Diana Carle