Insects are the most common class world wide, nearly one million species are known to date and some scientists speculate we haven't even scratched the surface. Its no wonder we're all a little confused or have misconceptions when it comes to bugs. Most of our problems come from simple misnaming. When it comes to Blue Winged Olives, this often occurs . Often a genus like callibaetis is referred to as a Baetis, when in fact it is a Baetidae (a little harder to say but it's much more scientifically correct.) Below is the nomenclature for those that find it easier to understand. Baetis, Callibaetis, Cloeon and Pseudocloeon's are all in the family Baetidae and are collectively referred to as Blue Winged Olives. Within the family of Baetidae lies over twenty separate genus's and again most of us refer to all of these as BWO's.
Kingdom Animalia (Animals)
......Pylum Anthropoda (Arthropods)
................Class Insecta (Insects)
........................Order Ephemeroptera (Mayflies)
..................................Family Baetidae (BWO)
....................................................Genus Baetis
....................................................Genus Callibaetis
....................................................Genus Cloeon
....................................................Genus Pseudocloeon
....................................................(many more!)
And enough of the stupid science, lets talk applicable science. If you would like to become confused I highly recommend investigating this subject further. The multitude of genera and diversity between them can make for an interesting study, I recommend the resource I used here, called "Mayflies. An Anglers Study of Trout Water Ephemeroptera" (see reference at end of blog.)
Baetidae are found throughout North America but predominate in weedy and nutrient rich waters. The nymphs will populate any body of water (stream, river, lake) that offers a cool, suitable environment. They can range from slow sections of freestone rivers to fast sections, gravel runs and riffles to slow moving spring creeks and among shoreline weeds in lakes. The nymphs are excellent swimmers due to their movement that actually resembles a minnow. They are usually pale to dark olive bodied and can vary greatly. Mature nymphs have dark, well developed wing cases and their legs darken to an olive brown.
When ready to emerge, the nymphs swim or float to the surface and shed the nymphal shuck. The surface film provides a huge barrier to the tiny insects, and many never pass through. Those that do must sit on the surface to allow their wings to dry and become rigid allowing them to fly away. During cool weather this takes longer to occur, so duns will float for greater distances on the surface. It is important to note that the naturals float very low in the surface film, with their bodies and tails flush. During this stage we can also fish cripple BWO's.
The Dun (sub-imago) sports two large sail like wings that point upwards and have blueish, grey coloring that can range from light to almost black. Typically within six to twenty four hours following emergence (highly temperature dependent) the duns molt into spinners (imago). If the emergence occurs in the morning the spinner fall usually occurs in the evening while if the emergence is in the afternoon then the fall will probably occur the next morning. Female spinners are usually identical to the duns but males have much lighter bodies, sometimes almost white. During this final molt the wing veins become highly visible called hyaline. After fertilization, the females enter the water after remaining on the stream side for the eggs to ripen, then deposit their eggs on submerged logs or vegetation, and then are washed away. Rarely, the males accompany the females.
Kingdom Animalia (Animals)
......Pylum Anthropoda (Arthropods)
................Class Insecta (Insects)
........................Order Ephemeroptera (Mayflies)
..................................Family Baetidae (BWO)
....................................................Genus Baetis
....................................................Genus Callibaetis
....................................................Genus Cloeon
....................................................Genus Pseudocloeon
....................................................(many more!)
And enough of the stupid science, lets talk applicable science. If you would like to become confused I highly recommend investigating this subject further. The multitude of genera and diversity between them can make for an interesting study, I recommend the resource I used here, called "Mayflies. An Anglers Study of Trout Water Ephemeroptera" (see reference at end of blog.)
Baetidae are found throughout North America but predominate in weedy and nutrient rich waters. The nymphs will populate any body of water (stream, river, lake) that offers a cool, suitable environment. They can range from slow sections of freestone rivers to fast sections, gravel runs and riffles to slow moving spring creeks and among shoreline weeds in lakes. The nymphs are excellent swimmers due to their movement that actually resembles a minnow. They are usually pale to dark olive bodied and can vary greatly. Mature nymphs have dark, well developed wing cases and their legs darken to an olive brown.
When ready to emerge, the nymphs swim or float to the surface and shed the nymphal shuck. The surface film provides a huge barrier to the tiny insects, and many never pass through. Those that do must sit on the surface to allow their wings to dry and become rigid allowing them to fly away. During cool weather this takes longer to occur, so duns will float for greater distances on the surface. It is important to note that the naturals float very low in the surface film, with their bodies and tails flush. During this stage we can also fish cripple BWO's.
The Dun (sub-imago) sports two large sail like wings that point upwards and have blueish, grey coloring that can range from light to almost black. Typically within six to twenty four hours following emergence (highly temperature dependent) the duns molt into spinners (imago). If the emergence occurs in the morning the spinner fall usually occurs in the evening while if the emergence is in the afternoon then the fall will probably occur the next morning. Female spinners are usually identical to the duns but males have much lighter bodies, sometimes almost white. During this final molt the wing veins become highly visible called hyaline. After fertilization, the females enter the water after remaining on the stream side for the eggs to ripen, then deposit their eggs on submerged logs or vegetation, and then are washed away. Rarely, the males accompany the females.
Much variation occurs throughout the generas and the following are some of the deferrals from the above information.
The Baetis Genus nymphs often congregate around weed beds or crawl up plant stems when emerging, though they can still emerge in the normal Baetidae form. Nymphs usually have markings or stripes that are paler than the other body segments. The female Duns are often brighter while the males are more subdued and the spinners have green females and brown males- the spinner fall occurs during the evening.
Callibaetis commonly called the speckled dun, are seen often in Alberta. They prefer lakes or very slow sections of river, so we will find them on the Bow River. Nymphs vary in color greatly, usually taking on the color of their surroundings and have long, slender bodies. The nymphs congregate under weed beds and once out of the surface film usually take only a few minutes to become air born as a subimago, their wings usually have a predominant white vein pattern. The most productive hatches occur on cool, cloudy days when the duns must remain on the water for greater periods of time.
As most of you know, there is a great amount of indecision and scrutiny that occurs in the field of entomology, if there are any mistakes in this writing please let us know. It is better to be proven wrong and be corrected then to be documenting inaccurate information! Your help is greatly appreciated.
All information was taken from either:
-http://www.troutnut.com/hatch/90/Mayfly-Baetidae-Blue-Winged-Olives taken Sept. 20, 2009.
-"Mayflies. An Angler's study of Trout Water Ephemeroptera" Written by Malcolm Knopp and Robert Cormier. Lyons Press (Guilford, CT) 1997.
Picture from:http://images.google.com/imgres?imgurl=http://www.onlinefishinglog.com/images/blog/2006_outdoors/blue_winged_olives.jpg&imgrefurl=http://onlinefishinglog.com/blog/8/Outdoor-Pictures-2006&usg=__N_9amYwLOaI1EsaSSdmqhmrkMeI=&h=600&w=800&sz=54&hl=en&start=17&sig2=BOGRLkWhS9QXyg_45Q9ZkA&um=1&tbnid=kkcsuRg5eafeYM:&tbnh=107&tbnw=143&prev=/images%3Fq%3Dblue%2Bwing%2Bolives%26hl%3Den%26rls%3Dcom.microsoft:en-ca:IE-SearchBox%26um%3D1&ei=qGi2SpbnMYLUsQOjh6XSDA
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