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

> > Mayfly Development



DOS has attached these 2 pictures to aid in identification. The message is below.
Shown Full Size
1
1
Shown Full Size
2
2
DOSMarch 19th, 2009, 12:06 am
Buffalo, NY

Posts: 64
Hello gents,

I collected these specimens today on a Western New York Spring Creek. I'm wondering if you can tell me what inferences I can make regarding development and sex, based on physical observation of these two Baetidae nymphs.

Andrew Nisbet
TaxonMarch 19th, 2009, 8:01 am
Site Editor
Royse City, TX

Posts: 1350
Hi Andrew,

I salute your curiosity. With regard to development, the 1st specimen with darkened wing pads would likely be in its last nymphal instar, and very close to time of emergence, whereas the 2nd specimen with wing pads of approximately same size might be of same or previous instar, and not as close to time of emergence. With regard to sex, I know of nothing which can be inferred from photos of mayfly nymphs.
Best regards,
Roger Rohrbeck
www.FlyfishingEntomology.com
GONZOMarch 19th, 2009, 12:00 pm
Site Editor
"Bear Swamp," PA

Posts: 1681
Andrew,

The nymph in the top photo is a male, and the other is probably a female. Sexually dimorphic traits like differences in body size and eye size can be seen in mature mayfly nymphs of many species, but these comparative differences can be a bit hard to interpret in photos unless both sexes can be seen side by side. Additionally, the developing claspers of males can sometimes be seen in mature nymphs (though these usually don't show in dorsal photos).

However, because these are baetid nymphs, the turbinate eyes of the males (the large reddish set of eyes on top of the head of the nymph in the first photo) can be seen on mature nymphs.

If I had to guess, I'd lean toward these being male and female B. tricaudatus nymphs. Many baetid nymphs also have different male/female color forms, and these seem to match up well with that species.
DOSMarch 20th, 2009, 12:57 pm
Buffalo, NY

Posts: 64
Hey guys,

Thanks for the insight. Your responses inspired lots of googling and book cracking in search of more questions and answers.

After thinking about these two nymphs and the location I collected them, I remembered that I encounter a Baetidae hatch in the same place last year at about this time, that offered up excellent fishing. I went back and checked my photo records and journal, sure enough I have pictures of the adults.

The insects were consistently a size 16. I'm fairly certain I can associate these two adults, male and female with the nymphs. Do you concur? Is it sound to make such an assumption?






Also.... I had this lovely lady emerge last night in my bug rearing aquarium. I found her this morning laying on her side in the surface film, not moving, with her wings crumpled. I took her out of the water, lifeless, assuming she was dead. I walked away to get the camera and when I came back she was upright and walking around.



Andrew Nisbet
GONZOMarch 20th, 2009, 5:59 pm
Site Editor
"Bear Swamp," PA

Posts: 1681
Andrew,

The top two photos look like male and female B. tricaudatus duns, and size #16 is about right for the early brood. Later-hatching broods become successively smaller.
MartinlfMarch 20th, 2009, 6:13 pm
Moderator
Palmyra PA

Posts: 3233
Great photos of my favorite may. Thanks.
"He spread them a yard and a half. 'And every one that got away is this big.'"

--Fred Chappell

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: stupid question
In Male Baetis bicaudatus Mayfly Nymph by Brian314
2Feb 27, 2022
by Brian314
Re: Hendrickson nymph
In Ephemerella subvaria Mayfly Nymph by Martinlf
3Dec 27, 2006
by GONZO
More Baetis nymphs
(2 more)

In the Identify This! Board by Millcreek
0
Re: M. ithaca in M. mediopunctatum section?
In the Mayfly Species Maccaffertium mediopunctatum by GONZO
3Sep 4, 2012
by Entoman
Re: Nixe species (kennedyi?)
(2 more)

In the Identify This! Board by Millcreek
4Sep 27, 2014
by Millcreek
Re: Callibaetis Spinner Habits
In the Mayfly Species Callibaetis ferrugineus by WildcatRob
8Jan 7, 2009
by Dgracia
Re: stages before emergence
In the Insect Order Ephemeroptera by Troutnabout
7Sep 18, 2006
by Troutnut
BQ Nymph
In Neoleptophlebia Mayfly Nymph by Martinlf
0
Re: Brown Dun hatch/swarm time?
In the Mayfly Species Ameletus ludens by Konchu
10Apr 30, 2009
by Troutnut
37 New Specimens Today
In General Discussion by Troutnut
0
Most Recent Posts
Re: large free living caddis rhyacophila?
In the Identify This! Board by Kjfeen (Taxon replied)