Order Ephemeroptera (Mayflies) in the Christopher B. Smith Preserve

Order Ephemeroptera Characteristics: Members of this order have extremely short life spans and emerge from ponds, rivers, and lakes in large numbers in summer months. This is the only insect order in which its members molt after developing functional wings.

The life cycle includes four stages: 1) egg, 2) nymph (aka naiad), 3) subimago, and 4) imago (aka adult). Stage 1: Eggs are laid in water, settle to the bottom, and stick to submerged objects. Most species lay their eggs in freshwater, but a few can tolerate brackish estuaries. Stage 2: Eggs hatch in ~2 weeks and a nymph emerges. Many molts may occur in the nymph stage. This stage lasts two weeks to two years, depending on the species and the environment. Stage 3: At the end of this stage, the skin splits down the back and a winged form (subimago) emerges. It flies from the water surface to a sheltered resting place. Stage 4: After an interval that lasts a few minutes to several days, the skin is shed for the last time, and the winged adult emerges. Common names for adults include spinner, shadfly, sandfly, dayfly, fishfly, and drake. Mating occurs very soon after the adult stage begins. In most species death follows mating and oviposition.

Each of the 6 legs of a naiad end in a single terminating claw. The thoracic region is rounded outward and has external pads that bear the developing wings. The abdomen is long and slender. Gills are on the upper surface of some of the body segments. The body terminates in 2 or three tails.

Adults have large compound eyes, short, bristle-like antennae, and non-functioning mouthparts and digestive tracts. Adults do not eat. Their wings are membranous. Front wings are large and triangular; hind wings are smaller and rounded. When at rest, wings are held together upright over the body. Adult mayflies have two or three, long threadlike tails.

Worldwide there are 2,500 species, about 700 in North America north of Mexico.

Interactions in the Smith Preserve: Mayflies are important in the energy transfer cycle in freshwater. The naiads of some species are carnivorous, but most feed on diatoms, algae, higher plants, and organic detritus. Mayflies are food for carnivorous animals (birds, bats, predatory insects, spiders, mammals, and especially fishes).

Family	Species Name	Common Name
Caenidae	Caenis sp.	Angler's Curses

Caenis sp. Angler's Curses The mayfly naiad above was 4 mm long. That measurement does not count the count the length of its tails. This specimen was netted with other invertebrates in the Smith Preserve pond by Conservancy scientist, Leif Johnson, on January 11, 2017. Once the mayfly was isolated from the sample, these photographs (image 1: dorsal view; image 2: ventral view) were produced using photomicroscopy and sent for identification to <BugGuide.net>, sponsored by Iowa State University's Department of Entomology. On January 24, 2017, the genus was identified by Brady Richards, a Contributing Editor to <BugGuide.net>. According to <BugGuide.net, The genus Canis is one of the largest mayfly genera with 13 species in our area and ~150 worldwide. Two/thirds of the species are neotropical. According to a fly fishing forum website, Canis mayflies typically emerge, molt into spinners, mate, and oviposit within one hour. Imitations of this mayfly are used for fly-fishing. Because these mayflies are so small, tying fly imitation lures this small is difficult and has resulted in its nickname "Anglers Curse." Return to top

© Photographs and text by Susan Leach Snyder (Conservancy of Southwest Florida Volunteer), unless otherwise credited above.

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