Stillwater Mayflies

[Taxon]

During the summer of 2007, biotic sampling was conducted in (1243) lakes across the (48) contiguous states by individual state agencies. The biotic samples were sorted to the lowest practical taxonomic level and counted by the US Environmental Protection Agency (EPA). Among other insect orders, there were (36) different mayfly genera of collected. Those genera are listed below:

1​	Acentrella
2​	Ameletus
3​	Apobaetis
4​	Baetis
5​	Baetisca
6​	Brachycercus
7​	Caenis
8​	Callibaetis
9​	Camelobaetidius
10​	Centroptilum
11​	Choroterpes
12​	Dentatella
13​	Drunella
14​	Ecdyonurus
15​	Epeorus
16​	Ephemera
17​	Ephoron
18​	Eurylophella
19​	Fallceon
20​	Hexagenia
21​	Leptophlebia
22​	Leucrocuta
23​	Maccaffertium
24​	Paracloeodes
25​	Paraleptophlebia
26​	Procloeon
27​	Pseudocentroptiloides
28​	Pseudocloeon
29​	Rhithrogena
30​	Serratella
31​	Siphlonurus
32​	Siphloplecton
33​	Stenacron
34​	Stenonema
35​	Thraulodes
36​	Tricorythodes

So, which one of the genera listed above would you guess was most prolific in samples collected?

 

[Zak]

8	Callibaetis?

 

[Tom Butler]

8	Callibaetis?

That's the only name I could recognize as being associated with a lake.

 

[Rob Allen]

I dunno about most prolific but for the lakes I have fished #8 is the only mayfly that matters. Like AT ALL..

 

[Matt B]

How is “prolific” meant in this context? Encountered most frequently (at any abundance) in the lakes sampled? Or the greatest number of individuals sampled across all the lakes pooled together?

 

[James St. Clair]

How is “prolific” meant in this context? Encountered most frequently (at any abundance) in the lakes sampled? Or the greatest number of individuals sampled across all the lakes pooled together?

I was just about to ask the same thing!

 

[Mark Melton]

#7 Caenis

 

[Matt B]

Caenis because Mark said it and because they are broadly distributed, generally pretty tiny and have been found in some very high densities in places, maybe at least partly because they are so small that a large # of larvae can fit into a small area.

 

[Mark Melton]

From Roger"s website.

Lakes Biotic Survey

 

[FinLuver]

Ants… mic drop

 

[Taxon]

Well, for those of you whose guess was Callibaetis, I must admit that would also have been my guess also, least before 2011. But quite surprisingly, apparently Caenis outnumber Callibaetis at a ratio of more than 4/1 across the US in freshwater lakes and reservoirs. Please forgive my tardy response. I'm somewhat of a night owl, who just got up to find numerous responses to the question that I had posed.

 

[Matt B]

Well, for those of you whose guess was Callibaetis, I must admit that would also have been my guess also, least before 2011. But quite surprisingly, apparently Caenis outnumber Callibaetis at a ratio of more than 4/1 across the US in freshwater lakes and reservoirs. Please forgive my tardy response. I'm somewhat of a night owl, who just got up to find numerous responses to the question that I had posed.

No worries, thanks for posing an interesting question. So that's for absolute abundance of mayflies across all lakes sampled, and it's not even close. It would be interesting to also know if Caenis also had the widest distribution of mayflies across the lakes sampled; in other words, the greatest number of "hits" of at least one individual for all lakes sampled.

 

[Zak]

Well, for those of you whose guess was Callibaetis, I must admit that would also have been my guess also, least before 2011. But quite surprisingly, apparently Caenis outnumber Callibaetis at a ratio of more than 4/1 across the US in freshwater lakes and reservoirs. Please forgive my tardy response. I'm somewhat of a night owl, who just got up to find numerous responses to the question that I had posed.

But which was most prolific by weight?

 

[Taxon]

But which was most prolific by weight?

Interesting question, but I don't know.

 

[Taxon]

Anyway, here are the top 10 with regard to number collected:

7​	Caenis	31455
8​	Callibaetis	6703
26​	Procloeon	832
34​	Stenonema (since mostly reclassified as Maccaffertium)	616
18​	Eurylophella	342
20​	Hexagenia	302
31​	Siphlonurus	292
10​	Centroptilum (since reclassified as Anafroptilum & Neocloeon)	216
25​	Paraleptophlebia	195
16​	Ephemera	157

 

[Chadk]

Most common in western wa? Eastern WA?

 

[Taxon]

Most common in western wa? Eastern WA?

It seems to vary depending on the lake sampled. Some of the lakes sampled in both western and eastern WA have Caenis, and some have Callibaetis, and some have both, and some have neither.

 

[Taxon]

It would be interesting to also know if Caenis also had the widest distribution of mayflies across the lakes sampled; in other words, the greatest number of "hits" of at least one individual for all lakes sampled.

Agreed.

 

[RCF]

@Taxon thank you for the initial question. Made me Google a lot and I learned even more. A very good thing!

Dang, they are small! No wonder I have not seen them and will not tie any either. LOL...