quarta-feira, 18 de maio de 2011

In search of the most rare Nimphalid of the Atlantic Forest: Prepona deiphile (Godart [1824]) (Nymphalidae: Charaxinae)

Some years ago in the sub-Andean cloud forest, Alex had his first glimpse of the variegated blue and red Prepona praeneste Hewitson, 1859, which swooped and flashed at extraordinary speed in its domain. Apart from this memory, only some grainy video remains, but the sight was unforgettable. Some years latter, he would try to find in its natural habitat, one of the finest Prepona - the classic iridescent violet-blue and gold spotted Prepona deiphile (Godart [1824]). This is undoubtedly the most magnificent and elusive nimphalid denizen of the 'Mata Atlântica' of South Eastern Brazil. Seitz states that von Bönninghausen (in the Victorian heyday of field naturalists/explorers) mentioned Petrópolis in the Organ Mountains as the habitat of P. deiphile. To this day, absolutely nothing is known of its early stages. This does seem to be the case, with all the rarest Nimphalids (including the finest Agrias sp. and Anaeomorpha), that they are very local and associated with one particular tree in thousands of acres of pristine rainforest! They also seem to choose, from the human standpoint, extremely difficult and potentially dangerous terrain.
Alex and Nirton
So after a brief phone call and some e-mail exchanges by mid-November, Alex, accompanied by his wife, and I decided to try a last hour trip to REGUA - Reserva Ecológica de Guapiaçu, our 'camp base' - in early 2011 to try to see and photograph that elusive insect. I myself always wanted to see P. deiphile in its natural haunts, in spite of the fact that this creature is very difficult to locate. There are however, a few 'classic' localites where this insect can be seen on an early basis. One of them is some Km away from REGUA, in Cachoeiras de Macacu county and precisely one of my friends – Mr. Nirton Tangerini - was its finder and thus knew with mathematical precision its occurrence there.

A narrow walkway leading to the dam

  Given the fickle nature of these Nymphalid butterflies, we made an expedition to the spot- more in pious hope- rather than anything certain. Even so, we were greeted with the first fine sunny days after the diluvium rains and bad weather that brought havoc to the Serra do Órgãos in January 2011. So we leave around 8 am to be sure we would be on place around 10 am, when those butterflies start to  become active, according to Mr. Nirton. So, around 10:30 we were on the spot, after a couple of hours driving through a secondary class dirt road and some 15 m walk up wandering a trail that leads to a small dam. The locality, at ca 500M, is a steep sided ravine with a small river mountain valley and mostly undisturbed rainforest.

The CEDAE dam

Forest on the opposite side of the walkway
The 'tobogan' water exit seen from the dam


On the dam we could see some leps quite fond of mud-puddling like some Marpesia and Hesperiidae.

Marpesia z. zerynthia zerynthia Hübner, [1823]

Marpesia chiron marius (Cramer , 1779)

Cycloglypha thrasibulus thrasibulus (Fabricius, 1793)

In our comings and goings along the trail we had a glimpse of a fraction of the local Atlantic Forest hotspot Biodiversity, with many sorts of creatures  easily observed... here under a sample
Catoblepia amphirhoe (Hübner, [1825])
Mylon maimon (Fabricius, 1775) - A NEW local record!

A Proscopidae walking stick!

A dayflying Geometridae moth: Atyriodes janeira (Schaus, 1892)
So we picked the best position we could, and with some banana bait and smears to encourage the animal, settled down to wait armoured with the best patience we could.
In this particular ravine, P. deiphile adults love to perch mainly on two local emerging trees, each one more than 15-20 m above the ground. Looking theese pictures will give a glimpse of the challenge ahead of us:
   Then...at lunchtime...and time was getting short... We saw a magnificent flashing arc like an electric ray. Violet-blue, gold spots and a dark brownish underside sweeping towards us. In Alex words "It is true I had seen some splendid Agrias and Prepona in their natural habitat... but nothing could compare with this. What struck me, in this fleeting encounter, were the magnificent curved forewings and gloss of its forewings as it carved its way through the air. The agility and velocity of movement and colour combination is probably the greatest sight to be witnessed in Nature."
Sooner a second individual, probably a male approached the same tree. Altough one of thme came circling around the tree shaft smeared with rotten banana, our wish to photograph* it seemed to faint away because of the habitat and time available... So we decided to take action! - That consisted in bringing in the 'secret weapon' - a device to attract butterflies - a piece of tissue of the same puprple color of this gorgeous species. As most of you must be aware, Morpho collectors use metalic blue decoys and frames to attract Morpho individuals down from the canopy.

By waving a purple decoy we managed to attract one male!
Speaking of Morphos... from 12 am on we could see splendid bugs like Morpho epistrophus epistrophus (Fabricius, 1796) gliding slowly and gracefully like small kites over the gully valley, spoted some individuals of Morpho helenor achillaena (Hübner, [1823]). Parides tros tros (Fabricius, 1793) not a scarce sight on that valley, albeight no Aristolochia wines were seen around, but it went really unnoticed due to our focus on P. deiphile. Another single majestic sight was a huge male of Heraclides androgeus laodocus (Fabricius, 1793) - new record in the area! - gliding down over the tobogan water exit of the dam.

That day we saw two male specimens of P. deiphile, always perching above 6-8 m above ground, and the next day only one. According to Mr. Nirton in some years one can see up to 15-20 individuals, in others only about 3-5; the numbers seem to be declining over the last decade. Anyway, in the early afternoon at last we managed to lure a male into the net and take a photo of a live specimen, altough not under a natural pose:
This was a memorable day and week, to be remembered for years to come... Was it 'luck'? - Or was it the utter knowlegde of Nirton on this particular species? - or both?... Alex just could have crossed an ocean and wasted is precious time and resources on a 'mirage'... but in his own words "Although this had to be the high point of our trip to the Atlantic Rainforest we did enjoy our various outings around the trails of REGUA in the good company of a Neotropical Lepidoptera enthusiast. His expertise enabled us to see some other bugs - our first Morpho anaxibia (Esper, 1801), Arcas imperialis (Cramer, 1775) and Evenus regalis (Cramer, 1775)."

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