Off on a field trip to Costa Rica

Well, if you like to eat frogs maybe......I wonder what the selective pressure is that favors bright colors in amphibians? Warning predators, competition for mates, or attracting mates, or maybe all of these?I saw a surprising number of different brightly colored species, but this was the only one I was able to photograph.Costa Rica has a high diversity of amphibians and reptiles compared to other parts of tropical America I have visited.

I don't know if these frogs can see these colors or not, but for their size they do have fairly large eyes. They all seem to live in habitat that is very dimly lit ( I would not have been able to photograph them without flash). Frogs also have distinctive calls that attract mates.They do see us well enough to immediately try to hide, but maybe their toxicity makes them so immune to predation that they never have to avoid it and their biggest worry is being stepped on by big clumsy humans.

I am headed out in the morning on a short, 5-6 day field trip to southern Oregon amd northern California. There are reports of large numbers of a dragonfly species, that has never been reported in OR, flying in a county in CA that borders OR. So maybe my friend and I can get a new state record.I also want to try and photograph and collect eggs and nymphs to rear of a very large species that is found in a few places in northern CA. Anax walsinghami is one of the largest dragonflies and their nymphs should be quite impressive. Good captive photo and video subjects.Like many other biologists, Odonatists are seeing a number of species expanding the ranges northward. Two species have expanded northward through Oregon and well into Washington over the last 20 years. I see many reports from all across North America for dragonflies and other entomologists are seeing similar things with many other insect groups.Tallyho

There are a lot of species that are red. It seems to be a favored color and some have red veins and/or red in the wing membrane.Texas is in a special spot geographically to see lots of new species for the U. S. and there are quite a few avid dragonfly watchers there.

Our working hypothesis is climate change. So far, the species have been generalists, so it is not really a factor of their habitat changing. More warm summer days and fewer cold winter days seem to be enough to allow them to breed and survive in lots of ponds and sluggish streams.We did find the species we were looking for that is new to Oregon, Tramea onusta. We got it in Curry County within a kilometer of the coast, on Wednesday. Today a guy posted from Medford in Jackson County that they were there, so as long as it stays hot we may even see them here in the Willamette Valley.Interestingly, Tramea onusta probably will not be able to breed successfully in Oregon. They seem to be a species that goes through the nymph stage quite rapidly and then they disperse as widely as possible, and breed whereever they find mates. They seem to be adapted to hotter regions and the nymphs do not finish development at the northern parts of their adult range. Normally, they and several other species that use this wide dispersal strategy oviposit and the nymphs develop in bodies of water that are temporary (that dry up later in the season) and that do not have predators. My hypothesis is that when they oviposit in more permanent aquatic habitats they are preyed on by the more numerous local species.ABE: We made it down to the are in California where I expected to collect nymphs and indeed I did collect a few that should be interesting to rear out. I got one male Anax walsinghami, but we were only able to get a few photos of it in hand. I will try and post some of those later to give you an idea just how large the monster is.We were on Bear Creek which is very near one of the large wildfires burning right now. Sunday morning when we woke up our vehicles and equipment were all covered by ash and the air was very smoky. Today I see that Hwy 20 is closed where we drove out on Sunday and a bunch of homes have burned and the fire has tripled in size. I am glad we decided to leave when we did.Oh, and we had an otter at one of the pools in the creek that sat on a rock and watched the crazy guys with nets and cameras. I post some shots of him tomorrow too.Edited by Tanypteryx, : No reason given.

I have been thinking about starting a new topic to discuss one of the talks presented at the dragonfly meeting I attended in Pennsylvania.The talk was about research into the dragonfly family Petaluridae (Tanypteryx is one of the genera in Petaluridae). The research was published in the journal Biogeography in 2014. There are only 11 species in the family and the study involved extensive DNA analysis of all the species and related their present geographical distribution with where those locations were when the super-continent Pangea broke up. The DNA studies indicate that the Petaluridae were already a dragonfly family then and that the split of the different species groups corresponds to the breakup of the continent. There are 2 species in North America. Tachopteryx thoryi is fairly widespread in the eastern U. S. and Tanypteryx hageni is confined to the Cascade Mts. in Oregon, Washington and British Columbia and in the Sierras as far south as Yosemite. Tanypteryx pryori is found only in Japan. Phenes raptor is only found in Chile. Then there are 4 species found in Australia and New Zealand. So, the distribution is roughly around the ring of fire, except for the species in the eastern U. S.This was one of the most interesting talks I have ever seen and heard and evidence was also presented that one of the species alive today is over 100 million years old and may be the single oldest multicellular species on the planet!Every one of us attending the meeting was completely blown away. One of the truly great things about these scientific meetings is the number of teachers who are there with their students and some of them have their own students now. The continuity of research and science is really quite extraordinary.Is anyone interested in discussing this as a topic? It seems to me that the group here might be able to give me some new insights.Edited by Tanypteryx, : spelling Chili

Thanks.

OK, here is a shot of the otter on Bear Creek. I am posting this shot because there is an out of focus, flying dragonfly in the frame, Libellula saturata. I think this shot is a little sharper and better framed. I went out and got some pond water this morning along with some small organisms to feed my nymphs, before they eat each other. So I need to get busy with that and then out to several ponds to check for Tramea onusta, the dragonfly we found in southern OR last Wednesday. It has been spotted at a pond only a dozen miles from here so if I can find it today it will be another new county record.

This is a stream species, Progomphus borealis at Bear Creek, CA. This species is in family Gomphidae and they are all called Clubtails because the segments near the end of the abdomen are swollen, in some species very swollen. Note also that the eyes are separated. Almost all of the species in this family are stream specialists.The Gomphids are a highly evolved group. By highly evolved, I mean there have been very many speciation events, so many that they really defy classification using the old standard Order, Suborder, Family, Subfamily, Genus and species. Cladistics works much better and the Gomphidae are going through a major revision right now, based on a combination of genetics and morphology.This is a really fun time to be a biologist because the technologies of DNA sequencing and computer databases are allowing us to have the clearest understanding of the evolutionary history of the groups of organisms we are studying. I have been searching for this species in Oregon for many, many years without success. The type locality is Oregon (the locality that the specimen was collected in that was used for the original species description), but it was described when it was the Oregon Territory, which included Oregon, Washington and Idaho. It has been found fairly close to the Oregon border and I have searched many rivers that look like good habitat, but so far nada.Edited by Tanypteryx, : No reason given.Edited by Tanypteryx, : spelling

Thank you. I did it all with my Brownie.

This first shot shows how smoky it was while we were collecting and the light had a very weird quality because of the smoke. On the left is what I would call a conglomerate made up of many kinds of rock in a solid matrix. Next a bit closer. This seems to be made up of stream processed sand, gravel, pebbles along with much larger rocks. Some of the embedded rocks seem to be fine-grained mudstone and sandstone. Some of the larger rocks also seem to have occlusions of iron oxide. Hanging out at EvC and reading the geology topics has infected me with a compulsion to photograph rocks where ever I go. There are a series of pools formed by rock dams and the only water that is flowing in the stream are small trickles through narrow notches eroded in the dams. The pools are quite picturesque and deep enough to swim in. This is a rather popular swimming area on hot afternoons.Looking at maps of the Rocky Fire (the largest wildfire in CA right now) it looks like the eastern edge of the fireline is along Bear Creek, so the vegetation in these shots may be gone by now.

Most of the time I so not seem to even see damselflies in the field, but I managed to get close to this female Argia translata. The black spheroids on the thorax are parasitic mites.

Thank you for you kind words. Thank you. Well, I like to think my camera is a pretty good one. It is older now, but has been my dream camera. It is a Nikon D700 12 megapixel with a full frame sensor. It was one of Nikon's first full frame digitals. It is a fairly low noise sensor which also make it very nice for night photography.The lens I used for that shot was a Sigma 180mm macro with a 2x teleconverter. It is a really sharp lens and with this setup it allows me to shoot without getting too close and spooking the subject. This lens died on the Costa Rica trip, so I was unhappy about that. Luckily, this is always something I worry about so I had 2 spare macro lenses with me. A very high resolution 200mm Micro-Nikkor and rare 70-180mm Micro-Nikkor. I shot most of the trip with the 200mm which made me sharpen up my game.I have worried so much about my camera dying on a trip that I bought a second D700 body before they quit making them. Nikon and Canon both make some amazing cameras and there are now a lot with sensors that are around 24 megapixels and Nikon has two that have 36 megapixels. One problem though for photographers shooting macro is the need for more depth of field. As magnification increases depth of field at a given aperture become shallower. To increase depth of field you need to use a smaller and smaller aperture, but smaller apertures cause increased diffraction which destroys sharpness. Diffraction becomes more pronounced in images as the pixel density of the sensor increases. It turns out that my 12-megapixel sensor is just about optimum for my style of photography. I hate photos of dragonflies where the depth of field is really shallow and the wings are completely out of focus. My whole life has been a quest for ultra high-resolution high depth of field images of insects. Sometimes it works.ABE: Sorry I forgot, the damselfly is about 5 cm long.ABE2: I wanted to add, that for better or worse I influenced 2 of my best friends to get the Nikon D700 also. They both shoot with the 105mm Micro-Nikkor lens, which may be the sharpest lens in the world. They both get extraordinary fine detail, that when we zoom in on it, shows things we never suspected before (details about how mating actually works, etc.). The shorter focal length means they have to be even closer to their subjects, but they have both really honed their stalking skills. The other 2 people that I routinely travel with both shoot Canons with Sigma 180mm macro lenses. All 5 of us travel together and continuously compare photographic results and help each other improve our work. Edited by Tanypteryx, : added subject length.Edited by Tanypteryx, : ABE2

AZPaul, Thanks for your kind words, they are very flattering. There are a lot of better photographers out there. When I see their work it inspires me to work harder.A lot of my shots are the result of luck.

Grasshoppers are sometimes quite colorful. They were surprisingly rare at the places we visited in Costa Rica. At least, I did not see very many, compared to Ecuador, Bolivia or Peru. This one had quite strikingly metallic colors on the pronotum (the green thoracic segment that bear the front legs) and head. It did not hold still for very long and turned away from me so that I could never get a shot of the front of the head. This specimen is fairly young and will go through a number of molts before it is an adult (note, the wing pads are quite short, in an adult they would be long enough to cover the abdomen). The nymphs can have completely different coloration between molts.