Thursday, January 28, 2016

Looking for insects in Costa Rica

Hmm…doesn't look like an aquatic insect???  No, no.  It's a beautiful Green iguana, male, in full mating colors.  It was a big one.  Measured 8-10' if we throw in the tail.  Another look -

Just gorgeous!

But I did find some aquatic insects.  We were in Tamarindo, Costa Rica last week -- before the BIG snow storm hit the East coast -- and one of our day trips was up in the mountains, visiting Rincon de la vieja National Park (Mt. Rincon is an active volcano).  And we did find some streams.  In fact, one was a nice cold water stream, but I didn't find anything in it.

In another small stream, one in which the water was quite a bit warmer, I had better luck.  Looking through leaf packs and at the bottoms of rocks, I found a number of caddisfly larvae.

Not a good photo, but the best I could do with my regular lens.  I was quite sure that it was a fingernet caddisfly larva (Philopotamidae), but I have no way to be sure, let alone talk about genus and species.  I didn't preserve it.  It was a "National Park," after all, and I wasn't sure if that was allowed, so I didn't have any sampling gear with me.  Alas.

I have no doubt that, at another time of year -- it's summer down there -- had I gone to the right parts of the country I'd have had a ball digging through streams, finding all sorts of different genera and species.  But we were on the west coast enjoying the beach and the tropical sunshine, so it was iguanas and Howler monkeys and mangrove birds that I pursued with my camera -- and telephoto lens.  Thought some of our readers might enjoy seeing some of my photos, so here we go.

I. Iguanas

We saw both Green iguanas and Black or "Spiny Tail" iguanas, all of them at the resort where we stayed where they were left to run free.  We've seen one of the Green ones, and here are some pictures of one of the Blacks.

II. Shore Birds in the Mangroves

and some blue jays, which in Costa Rica are crested and have longer tails than those we see in Virginia.  One in the wild,

and one that was eyeing our breakfast!

III. Coati mundis  (pr. kwati mundi), related to raccoons

One was eating (used) toilet paper!

IV.  Howler monkeys

They woke us up in the morning and scampered around in the trees for the rest of the day.


It was a wonderful trip, some place to visit if you get the chance.  But, if I can afford to go back, it's off to the mountains and streams, and I'll be toting my sampling equipment!

Back here -- it's time to get out to the streams.  I hope to be out there next week, but it will depend on the snow and the water levels after the melt.

Saturday, January 2, 2016

Exploring new streams: small tributary of the Rapidan River

I'm determined this year to explore some new streams.  This morning, I decided to finally look at a small mountain stream that empties into the Rapidan River right at Graves Mill.  I headed upstream until I was pretty well into the mountains and found a good pull-off.  It was a small stream, and sure enough, I found a lot of small mountain stream insects.  Nothing new -- but I got some good pictures.

1. In the photo at the top of the page, a "roach-like stonefly," genus Tallaperla.  Lots and lots of them in the leaf packs and in packs of leaves and twigs mixed.  I keep hoping to find genus Viehoperla, but those nymphs have single thoracic gills: this one clearly had two.

2. A flatheaded mayfly, Maccaffertium merririvulanum.

Very clear on this nymph are the characteristic pale "V's" on terga 5 and 7-9.  Can also see one on segment 4.

3.  And a nice pic of the Ameletid mayfly, Ameletus cryptosimulus.

This species is not all that common.  Consequently, in North Carolina, no tolerance value has yet been assigned.  Again, characteristic markings show up very well on this nymph.  "Each abdominal tergum with two pairs of pale spots, one submedian pair and a pair anterolateral to those."  (Beaty, Walters, and Holland, "The Ephemeroptera of North Carolina, version 4.0" p. 1.)  Earlier, in version 3.3 of this guide, Beaty had noted that there are "submedian curved marks on tergite 7 followed by a median spot."

And then there are the caudal filaments (tails).  "Caudal filaments basally brown...with a dark brown medial band followed by a pale band and tipped finally with brown." (Beaty, Walters, and Holland.)


Also saw lots of Perlodid stoneflies -- Malirekus hastatus and Diploperla duplicata.  On my list for next week, the Middle Fork, or the South Fork, of the Moormans.  Looking for some new Uenoids.

Oh -- an important note.  A revised version of "The Plecoptera of North Carolina" was posted on December 15.  Go to: