Tuesday 23 February 2010

Oding in Mauritius

The SSR (Sir Seewoosagur Ramgoolam) Botanic Gardens at Pamplemousses, have some reasonable habitat to accommodate some of the common odonata species of Mauritius.

The first water I came to was the Victoria lily pond. Dragonflies seemed to like the raised edges of the lilies and 4 species were quickly found here.
The first appeared dark from most angles but when the light caught it a deep blue was apparent. Trolling through the photographs on http://www.africa-dragonfly.net/ I found a likely suspect in Black Percher Diplacodes lefebvrii It spent much of it’s time chasing off other odes that entered it’s airspace.
The second ode of the day nearly fell prey to a young Green-backed Heron. The large blotches at the base of the hindwing, the distinctive venation and the yellow/brown triangular windows give me confidence to name it as a Phantom Flutterer Rhyothemis semihyalina.
Number three was an Aeshnid which would not sit to have his picture taken. I believe that it was the Blue Emperor Anax imperator as the only blue aeshnid I can see evidence of in Mauritius. It was present at every body of water and moist patch that I encountered.
Number four stayed at some distance but the yellow spots on the side of it’s abdomen gave me cause to consider Ringed Cascader Zygonyx torridus as an initial identity. Z torridus does occur in Mauritius and I could find no other suitable candidate until I checked the female Black Percher which is a real possibility. Close by is a shallow grassy pond, fed and drained by a stream. On prominent points around the pond, 2 types of skimmer were conspicuous. One was an Orthetrum species. The very pinched abdomen at S3 &4 possibly indicated the Epaulet Skimmer Orthetrum chrysostigma, but I rather fancy Spectacled Skimmer Othetrum icteromelas for this one. It has a dark shoulder stripe and darker anterior margins to it’s pterostigma.
The other was the increasingly familiar Violet Dropwing Trithemis annulata. This ode has gained popularity with this blogger because of it’s ease of identification. But now I come to look at the last sections of it's abdomen..... can anyone confirm please?
Perched on debris in the draining stream was my one and only zygoptera of the day I have yet to identify this one. It seemed to prefer being very close to the water. It either perched on midstream debris or on low, overhanging grass.
Lastly, a poor observation of yet another frustrating Orthetrum. I noted the stripes on the thorax, but have nothing that compares to it in any information that I can find.

Tuesday 9 February 2010

A tiny ornamental pond in the grounds of the ITC Maratha hotel gave me cause to hunt out my red crayon. While steeling myself for the frenetic traffic of Mumbai, I took a quick turn around the gardens and saw a beautiful, lemon yellow zygopterid flitting between the lily pads.
After consulting http://www.asia-dragonflies.net/ I have decided that it is a Ceriagrion coromandelianum.
On to Powai Lake within a 10 minute taxi-ride from the hotel. The water margins were choked with water hyacinth, but there seemed to be little in the way of odonata there. Instead, where the weeds had been pulled from the water and allowed to dry, Asian Amberwings, Brachythemis contaminata, were in position on prominent stalks. These were by far the most populous dragonfly of the day, seemingly abundant all around the lake.
A rough road ran alongside the lake leaving a stagnant ditch separating it from the main road. The ditch held damselflies with another C. coromandelianum and some of what I suspect to be a Pseudagrion sp possibly microcephalum (Pseudagrion microcephalum has been confirmed by Saurabh Sawant, the mastermind of Mumbai).
One was hovering over the water and I wondered if an in-flight shot might be possible. I was pleased with the way it came out. Two other damselflies have me stumped at the moment. My usual method is to consider females and young males or colour morphs of species already seen, but I can’t find a good match. They are currently labelled Mumbai ode 01 and Mumbai ode 02, but I feel they deserve better names than that (Saurabh Sawant again comes to the rescue with Ischnura senegalensis).
If anyone can make any suggestions for identification, or point me in a good direction to look, I would be very grateful. I am also still looking for a decent field guide to Indian odonata if anyone knows of one.

Odonata species; 4

Ceriagrion coromandelianum 4, Pseudagrion microcephalum 8, Ischnura senegalensis 2, Asian Amberwing Brachythemis contaminata 150