Aquatic entomology is the study of aquatic insects. Although it is a discipline in its own right, it often interacts with other disciplines or forms an integral part of them. For example many aquatic flies are important as disease vectors, hence aquatic entomology interacts with medical entomology and parasitology. Aquatic insects contribute significantly to fresh water ecosystems, one of many groups of organisms that, together, must be considered in the study of aquatic ecology. As such their study may be a significant part of understanding the ecological state of a given ecosystem and in gauging how that ecosystem will respond to stress.

Use of aquatic entomology in Environmental Protection:

It would he difficult to overestimate the importance of aquatic insects as food items for other animals, particularly in the food webs associated with wetland environments. Many fishes, amphibians, shorebirds, waterfowl, and other animals forage heavily on both the aquatic and terrestrial stages of aquatic insects, which are essential to their survival.

It is imperative that society fully understand the potential consequences of the uses and alterations of the earth's natural environment. Environmental scientists have come to realize that uses or changes of waterways and lakes may have dire short-term or even irreversible long-term effects, not only on the quality of water itself but also on aquatic ecosystems. As a result, research has been employed to ascertain the effects of perturbations on our water resources and to increase our knowledge about the makeup of natural communities of aquatic organisms and their relation- ships with natural environments.

To this end, aquatic organisms that may be affected by an impending alteration or activity are often surveyed as part of an environmental assessment or impact study. this should be done, tor example, before impounding a river to create a reservoir; before dredging a stream; before constructing power plant cooling facilities, sewage treatment plants, or factories that may deliver potentially toxic effluents into a river or lake; before mining or deforestation activities; or before spraying chemicals over wetlands and forests. Measurements of the richness and diversity of aquatic insect species in relationship to the chemical and physical characters of their environment provide very usable indices for such baseline studies and are commonly made for these purposes.

Aquatic insects and other bottom-dwelling organisms in freshwater systems are also monitored in order to gauge subtle and profound effects that changes in water quality have on aquatic life. Changes in the composition of bottom-dwelling communities, as measured both qualitatively and quantitatively, will reflect, to various degrees, either non-optimum or intolerable quality shifts that result from the addition of pollutants to the water. Sources of such pollutants may be continual, intermittent, or accidental, and they may originate either from precise points or from large areas.

Bio-monitoring of this sort has some decided advantages over chemical and other types of water analysis. Bottom-dwelling insects and other invertebrates, by their very nature, maintain a relatively stable position in the aquatic environment. Thus the community composition can reflect either previous or long-range shifts in water quality. Analysis of water chemistry or of highly mobile aquatic animals such as fishes tends to reflect the quality of water only at the times that samples are taken.

Aquatic insects are also used in bioassay work. Laboratory bioassays are performed to determine the toxicological effects of pesticides on aquatic insects. The pesticides may be those that are intentionally used in aquatic or adjacent environments for the control of mosquitoes and other pests or they may be those that inadvertently find their way into aquatic ecosystems, for

example, via agricultural runoff. Such bioassays are commonly used to ascertain effects on non-target aquatic insect species, and thus have a direct relationship to environmental protection. In addition, several aquatic insects are studied in the laboratory in order to determine the mode of action of pesticides and the relative tolerances that these insects have for pollutants, such as heavy metals, organic enrichment, and heated waters.

Aquatic insects for which sufficient toxicological data are available have some potential for being used in field bioassays. That is, caged stock populations could be implanted at various points in a stream-for example, at the source (or supposed source) of a pollutant, upstream from the source, and downstream from the source. The relative mortality of these implanted populations could then be used as pollution indicators. Certain fish species have been commonly used in such field bioassays.

We will use aquatic insect study as part of the overall habitat assessment for the Jemez Mountains, and perhaps for other areas, as an indicator of biological health and diversity. There are many methods for sampling aquatic insect populations: screens, nets, artificial substrate samplers, grabbing devices and dredges. Most of these are used in both fresh and salt water environments. A few of these are shown on the accompanying Aquatic Insect Sampling Devices.

We will use a modification of the substrate sampler in which the substrate is made of leaves ratherthan being artificial. The leaves used are generally those of the gambel oak which provide flatsurfaces like the plate sampler, which have nooks and crannies like the rocks, but which also areorganic and attract insects which eat organic matter. Most aquatic insects are considered benthic because they are found associated with the bottom or with a substrate, but they occupy virtually every possible niche within their habitat. [See below] Some are clingers, clinging to the substrate with grasping claws or disks; the sprawlers crawl along the protected surfaces of the substrates; climbers reside on aquatic plant stems and other shoreline substrates; burrowersburrow into the soft bottom; floaters and swimmers are not associated with a substrate for attachment. The water skaters seen on many streams are examples of this type.

Aquatic insects, like other insects, go through life cycles which include embryonic (egg) stages as well as post-embryonic stages which may include larvae, pupae etc. leading to the sexually mature adult stage. The term for passing from one stage to the next is metamorphosis.

We will mostly see larvae upon examining the leaf packets left in the streams. These insects are very small and will be examined with a stereo-microscope (a dissecting scope) which renders them up to 45 times their actual size. They will have been fixed at retrieval with Kales Solution, a combination of alcohol, formalin, and acetic acid. This solution is very pungent and irritating to the nose and eyes. Be careful to avoid too much exposure when viewing the specimens.

Aquatic Insects from Jemez River [view sketches on Jemez Insects page][Click on photos for enlarged image.]
Mayfly - The larvae live 1-4 years in water, feeding on debris and small animal life. The last stage molts into a winged form which molts again into the adult. Mating and egg-laying occur quickly over water and the adults die.
Caddisfly - Adults are often seen around porch lights near water and mistaken for moths; the larvae build cases of sand grains or plant fragments and crawl over stream bottoms or weave small nets to catch prey in current. Adults are short-lived or rarely eat.
Stonefly - Habitat is streamsides and shores of lakes and ponds. Eggs deposited in masses in water; larvae mature in 1-4 years, adults live 2-3 weeks.
Chironomidae - These are small mosquito-like insects, midges and the like which inhabit marshes and ponds, woodlands, meadows, gardens near water. Eggs laid in water after mating swarm; larvae eat decaying plant matter. Mature larvae float to surface and pupate; adults released at surface.