Fly Fishing for Trout Home
User Password
or register.
Scientific name search:

> > i posted this in the forum, but...

This topic is about the Insect Order Ephemeroptera

Mayflies may be the most important insects for trout anglers to understand. They are an ancient order of insects, famous outside the fly-fishing world for their fragile beauty and short adult lifespan, often a single day to mate and die. The mayfly's poignant drama attracts poets and anglers alike, but anglers make the most of it.

Mayflies live more than 99% of their lives as nymphs on the river or lake bottom, filling many crucial roles in freshwater ecosystems as they feed and grow. They eventually emerge from the water as winged sub-adults called "subimagos" by scientists and "duns" by anglers. Duns evolved to be good at escaping the water, with a hydrophobic surface and hardy build, but they are clumsy fliers. Within a day or two they molt one last time into "imagos" or "spinners," the mature adults, a transformation captured in this photo series of a dun molting into a spinner. They have longer legs and tails, and sleeker, more lightweight bodies, giving them the airborne speed, agility, and long grasp they need for their midair mating rituals. They are usually darker than the duns and have shinier, more transparent wings. They die within minutes or hours after mating. Read more...

There are 823 more specimens...

The Discussion

RckregoApril 18th, 2007, 11:32 am
Princeton, NJ

Posts: 2
What's the difference between olives and bwo's? I've been told that there is a family or genus difference, and accordingly there are size and color differences. Is there anything definitive about this? Do the nymphs act differently? Are the hatches at different times of the year? Are the wings of olives really different from the wings of BWO's? thanks.
Here fishy, fishy, fishy...
TroutnutApril 18th, 2007, 12:03 pm
Bellevue, WA

Posts: 2737

I hope you don't mind I deleted the other topic -- it'll get confusing if we have people answering your question in two places.

The short answer is that you just can't get this technical about common names like olives and BWOs. BWOs usually don't have blue wings anyway, and lots of them aren't even olive. People slap those labels on just about anything green or small except for inchworms. See one of my articles on this site for more about the common name confusion.

When you start wondering about details and distinctions like this, that's the time to take the plunge into scientific names. Your questions can't really be answered for "BWOs" or "Olives", but you can learn all kinds of interesting details about Baetis or Drunella. :)
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist

Quick Reply

You have to be logged in to post on the forum. It's this easy:
Username:          Email:

Password:    Confirm Password:

I am at least 13 years old and agree to the rules.

Related Discussions

TitleRepliesLast Reply
Re: mayfly common names
In General Discussion by Konchu
10Nov 30, 2006
by DMM
Re: Help identify this...dragonfly?
In the Identify This! Board by Fallen513
6Nov 4, 2011
by Dinerobyn
Re: Wow
In Female Baetisca laurentina Mayfly Dun by Taxon
1Jun 26, 2006
by Troutnut
Re: Hook Wire
In Fly Tying by Entoman
15Aug 21, 2011
by Softhackle
Re: White Miller Bug
In the Caddisfly Species Nectopsyche albida by MIKE54
3May 4, 2013
by Adirman
Re: Kennebago Mayfly
In the Identify This! Board by Kennebago
3Jan 10, 2012
by Entoman
Re: Some September pictures, including fish
(15 more)

In the Photography Board by Jmd123
8Sep 23, 2018
by Jmd123
Re: Baetis doesn't look like a BWO!!
In Female Baetis Mayfly Dun by Adirman
10Sep 12, 2010
by Martinlf
Re: Invaria nymph
In Ephemerella invaria Mayfly Nymph by Martinlf
18Nov 30, 2009
by Oldredbarn
Re: Baetis v Empheralla Attenuata
In the Identify This! Board by Byhaugh
5Dec 18, 2013
by Entoman