Netta Smith and I visited REGUA for almost two weeks in late October to enjoy the pleasant atmosphere of the lodge and the wildlife of the area, but our special purpose was to look for dragonflies and damselflies. Tom Kompier has done a superb job of surveying the area, but you just about have to look at every wetland of every kind to find all the members of the order Odonata, so new species are always possible.
On October 24, we visited a tiny, densely vegetated pond by the abandoned house on the Waldenoor Trail and found Lestes pictus, a new species for REGUA. This beautiful spreadwing damselfly is known from relatively few records from Peru, Argentina and southern Brazil (Mato Grosso, Espirito Santo, Rio de Janeiro and São Paulo).
Male Lestes have a pale blue or grey abdomen tip, but in almost all species the colour comes from a powdery bloom called pruinosity. In Lestes pictus, the colour is instead a reflected blue like that of many other damselfly species.
We encountered 78 species of Odonata during our visit, not even half of the species known from the area, but still a very impressive list for a short visit at the end of the dry season.
There is a group of darners that fills a special niche in the dragonfly world. These are the duskhawkers, a group of medium to large dragonflies with habits that set them apart from most other species. Although there are other dragonflies with somewhat similar habits, I speak of the members of the genera Gynacantha and Triacanthagyna.
They avoid the hot and sunny hours of the day, but fly for relative short periods in the evening, most commonly in, but not restricted to, the autumn and winter months. Some species occur when it is still relatively light, others when it is almost dark. During those restricted hours they hunt for small insect prey, mostly mosquitoes. During the day they hang inside the forest amongst tangles and vines, or clinging to tree stems, waiting for the feeding frenzy to start when the sun sets.
On cloudy days some species may fly about inside the forest, or even appear at the forest edge, but only at the appointed time do they venture into open areas. Some species patrol small areas just above the ground, flying in straight lines, like G. mexicana, or above small waters, like G. bifida. Others, like G. nervosa, fly in more irregular patterns.
These three species are the representatives of Gynacantha have so far been found in the lower foothills at REGUA and all three are appearing relatively late, with G. mexicana flying so late that it appears often as no more than a ghost, an ephemeral shape flitting in and out of reality. Meaning that you see it for an instant, but when you register seeing it, it has already disappeared into shade, only to reappear and disappear again and again while you try to follow its flight pattern. A wisp of smoke, a spirit, moving in complete silence a feet or so above the ground. High up, around 1000 masl, there is a fourth species, G. adela, that appears to fly earlier, or even in the middle of the day when there is cloud cover.
These large duskhawking darners are preceded by the members of the genus Triacanthagyna. These are somewhat smaller and occur in higher numbers, regularly swarming with a hundred or more over open spaces. One moment they are not flying and the next they cascade out of the forest into the open in the hour before darkness, to dance around, sometimes high in the sky, sometimes low over the fields, and to retreat suddenly at twilight, to be replaced by the members of Gynacantha.
Three species have been identified until now at REGUA. The larger T. caribbea is the first to appear, when it is still very light, soon joined by T. nympha, a species somewhat smaller, but very similar in general appearance, and later again by the often abundant T. septima. There may be other species in the area. The trouble is that duskhawkers are difficult to catch or observe, irrespective of their abundance, due to their crepuscular habits and often very erratic flight patterns. That is of course exactly why they are such an exciting group.
There are the Argia damsels, the most speciose genus of New World Coenagrionids, and then there is Telebasis, with almost 60 described species the second most speciose genus. Telebasis species come basically in two flavours, red and blue.
In REGUA up to four species have now been identified, all belonging to the reddish species. And with their bright red abdomens these tiny damsels are reminiscent of the precious blood coral from the oceans. Although they can all be recognized in hand by the shape of their appendages, it is in fact possible to separate them in the field. To work out the field characteristics of Odonata to aid their identification is one of the main purposes of our work at REGUA.
When visiting the wetlands at REGUA the most common of these four species, T. corallina, is hard to miss when you know where to look. As all Telebasis species, it is relatively inconspicuous, mostly staying low in the grasses along the verge of the wetland and amongst the emergent vegetation in the wetlands. But when you take the time to peruse such places you realise it is in fact all over the place.
The third species is T. griffinii. It is very similar to T. corallina, although somewhat smaller. Apart from the dorsal side of the thorax, which is marked by a more diffuse dark cloud along the dorsal ridge instead of the two clear-cut straight lines of T. corallina, it differs in having a red snout, not lime-green. It seems to inhabit even better quality ponds, with lush emergent and floating vegetation and forested edges. At REGUA it has been found at two locations. These records are of note, as the species had not been recorded at Rio de Janeiro state before.
The last species to mention has been recorded at only one location and is probably rare in Rio de Janeiro state. This is T. carmesina, another species very similar to T. corallina, but with broader clear-cut stripes along the dorsal ridge of the thorax. Like T. corallina, its snout is greenish, but the ventral side of the thorax is whiter and the appendages are differently shaped. That is difficult to establish in the field unless it is caught and because it is so similar to T. corallina it may be under recorded. Like its brothers and sisters it keeps to the emergent vegetation along the edge of ponds.
If we take a quick look at the relationships in the genus, T. corallina was recorded together with all three other species, T. griffinii was seen with both T. corallina and T. filiola, but T. carmesina only with T. corallina. There were no bushes and trees along the verge of the pond where it was found, which may explain the absence of the other two. Now, the million dollar question is: which congeners did T. filiola occur with?
After the very productive survey in September-October it seemed unlikely to top its result of 115 identified species, but just the first week of our December-January survey we already topped 130. Of all 173 species recorded during our research to date, a cool 160 were found during our recent three week research period. To put that number in perspective, this is well over the number of Odonate species recorded in the whole of Europe.
With the advent of summer, not just the temperatures were up. Dragonflies and damselflies were abundant and not only in the obvious places. Of course the wetlands around the lodge were very productive, but now the trails in the forests also yielded many species all the way up to 1000 masl and higher. It is on the forest trails that many of the endemic damselflies are found. Let’s take a look at some of the more spectacular finds.
After a brief glimpse of an emerald Corduliinae in April 2012 at the top of the Salinas trail at approximately 1050 masl, at last emeralds were relocated again. In hand the species was verified as Navicordulia kiautai. This is one of the rare Atlantic Rainforest emeralds and had been recorded only twice before and never in Rio de Janeiro State. On subsequent visits it was seen regularly patrolling at midday above a wide trail bordered on both sides by forest. Up to six individuals were seen on any given day. Maybe the flight period is restricted, as it is unlikely that it was overlooked on previous visits.
Unexpected as well was the pretty Phyllocycla species recorded in the amazingly productive forest fragment not far from the lodge at 30 masl. This patch of lowland forest is part of the reserve and a testimony to its wealth. To date 10 gomphids have been found here and at least four Phyllocycla species are present. This individual stood out because of its very distinctive and whitish patterning, quite unlike the other gomphids present. Eventually it could be identified as P. viridipleuris, a species of which the occurrence in southeastern Brazil is shrouded in mystery. Likely, it is rare.
There are many species of Leptagrion forest dwelling damsels in Rio de Janeiro State, but during the whole of 2012 during all surveys only once a female Leptagrion was seen that did not belong to the omnipresent Leptagrion macrurum. At long last Susan Loose, a volunteer working on Odonata, located an unknown Leptagrion species at the beginning of the Green Trail, which turned out to be L. elongatum. Not a day after it was photographed and identified, a female of the same species was found right next to the reserve office!
Another interesting and surprising find at the forest fragment was a Mangrove Darner Coryphaeschna viriditas. On a very hot day an older female was found hanging along the forest edge. Professor Carvalho commented on the rarity of this species in Rio de Janeiro State. Clearly any greenish larger Aeshnid deserves careful attention, as they are around!
The last species to mention, although not mentioning all the other gems encountered is really an insult to them for which I apologize, is a Minagrion. After the September-October survey we did a short special to introduce this fabulous genus. During December we saw both Minagrion ribeiroi, so that species definitely also flies during the austral summer, and a third species, beautiful orange and blue Minagrion waltheri. This was found in bogs on the plain at Salinas, where is keeps inside the grassy emergent vegetation. It is another fabulous representative of this exquisite genus. Now three of the known five species have been recorded at REGUA.
Minagrion is a genus of rare and beautiful damselflies almost completely confined to the south-east of Brazil. Five species are known, of which two have been found during our survey at REGUA. Typical for the genus is that they have a process at the venter of S1, something difficult to see in the field, but that can be seen in the hand.
Rare Minagrion mecistogastrum has a very long and thin abdomen. The immature males are beautifully patterned with yellow, black and light blue. With age the males become strongly pruinose, obscuring the colors. They then are mostly bluish. At REGUA a young male was found in lowland forest away from water, but adult males were found perched along the heavily vegetated margin of clear pond about 30 cm over the water’s surface.
A spectacular find was the very rare Minagrion ribeiroi, listed as critically endangered by the IUCN. Unlike its congener M. mecistogastrum it has more usual proportions. The observed males had not developed pruinosity and presumably they keep their beautiful colors as adults. Their abdomens are largely ivory-white, rare amongst odonates. Several males and females have been observed at the forest edge close to a heavily vegetated and clear pond. Typically they would perch on a twig just inside the forest, but exposed to the sun. From their perch they would sally and snatch small insects out of the air in the immediate surroundings, to return to the same sunny perch, a habit that makes them relatively easy to spot.
Both species have been observed in winter only, M. ribeiroi in July and September, M. mecistogastrum in September. Whether they really only occur in the cooler period of the year is subject of further study. For odonate enthusiasts these species are another fantastic attraction at REGUA, although one will need patience and luck to encounter them.
Between September 22 and October 6 we did another survey of dragonflies and damselflies at REGUA and its immediate surroundings. 18 new species were added to the list for the Guapiaçu catchment, taking the total for this year to over 150 species, a testimony to the fantastic diversity of the ecosystem. Just in the wetlands next door to the lodge, already more than 60 different species can be found. Below we introduce just a few of the findings.
With the advent of spring the Gomphidae returned to the scene. A spectacular find was a dragonfly that may be the first recorded male of Praeviogomphus proprius. It will be studied further at the department of entomology of the Museu Nacional in Rio de Janeiro, thanks to the support of Prof. Alcimar do Lago Carvalho for the project. Praeviogomphus previously was only known from one female and from a few larvae. Other spectacular new gomphids were two species of Phyllocycla. Aphylla molossus, a large gomphid was also found regularly again.
Another great find was a species of Castoraeschna that may be new to science. This lovely dragonfly was found patrolling the bogs at Salinas, in the mountains above the lodge. Nearby an intriguing female Leptagrion was found that also still needs to be identified.
Tiny and elusive Peristicta jalmosi, only recently described, was found inhabiting a stream close to the old wetland, where males were hanging from the tips of leaves of trees in shady parts low over the water. These damsels are so small that they become next to invisible the moment they start flying. The fact that they perch in dark shady places obviously does not help either, so possibly it has been overlooked in the past.
The trails turned up two new species of Heteragrion. This fantastic genus of beautiful and big damselflies keeps on turning up new species that are often as localized and rare as they are spectacular. The specific identity of these two species still needs to be confirmed and it is well possible they are as yet undescribed. So far this year this fabulous genus has turned up seven different species, the commonest of which is H. aurantiacum, which can easily be seen at streams around the lodge. Another more regular, if uncommon and difficult to find, species is H. consors.
Clearly amongst the many attractions of REGUA is also a fantastic Odonata fauna.