© Anthony C. Terceira
To the trout fisherman, it is a time of frustration. To the casual observer it is a swarm of "millions of mosquitos" and a time to head the other way.
Throughout North America and the world, the hatching of midges is a continual process during the warming months of the year. These small (6 to 8 mm total length) insects hatch and appear as floating dust above the water's surface.
The order Diptera in which the "midges" are found comprises approximately 16,150 species in North America. Characteristically the larvae are legless and worm-like. Adults have one pair of wings, soft bodies and undergo complete metamorphosis. The phantom midges (Family Chaoboridae) are very similar to mosquitos and occur in pools and ponds. Some larvae are so transparent they are commonly known as glassworms.
Members of the genus Tendipes, of which there are about 200 species have red larvae called bloodworms. Hemoglobin within the larvae cause this bright red coloration. Males of the genus generally have small antennae which are plumose. They are found almost everywhere in very large numbers. The bloodworms are an important food available for the Tropical Fish Hobby. They are available frozen or freeze dried and provide a wonderful addition to most fres water fish's diet.
For a great portion of their life, these small flies spend their time under the water. The life cycle is approximately 6 weeks which allows for several generations within each pool and during any one season. The eggs are laid early in the spring as gelatinous globules on leaves and debris just under the water, close to the shore. Eggs hatch and larvae grow at different rates. The larvae or bloodworms spend their life concealed in the sandy or muddy bottom feeding on microscopic phyto and zooplankton. They grow to a total length of 3 to 30mm depending upon the particular species. When the larvae is ready to pupate, the process begins slowly with the feathery gills developing first. At this point the red coloration begins to darken and the soft wormlike case begins to harden. This continues for 20 to 50 hours until the pupae is completely formed. During this time the larvae continually moves back and forth in a wave-like pattern as it spends more time exposed above the bottom than below. Once the pupae is completely formed, it begins to ascend to the waters' surface. Once at the surface of the water, the adult begins the strenuous task of climbing out of its pupae casing. The head is the first part to break the surface tension and is followed by the first pair of legs attached to the thorax region. The wings are still folded and remain so until the entire abdomen is free of the pupae casing.
Once resting on the surface film of the water, the wings slowly unfold and are dried by the sunlight and wind. When the wings are dried , the adult quickly leaves the vulnerable water surface in search of a mate to begin the cycle again. Not all adults are able to successfully leave the pupae casing and lie dead partially contained within the casing. Still others are not completely developed and are not able to leave the water's surface, there they remain to become food for the other inhabitants of their freshwater environment.
During the summer season, the swarms are regular occurrences and, at times, the adults are so dense that they appear to engulf a passerby. Most midges resemble the dreaded mosquitos in appearance only, few inflict bites on humans.
There are many wonderful insects who spend much of their life underwater and hidden from our view. If we spend the time to look very carefully maybe we'll be lucky enough to see these amazing little insects right in our own neighborhood at one of the local fresh water ponds.