03 November 2012

Corvo Orthoptera

This is my first foray into Azorean Orthoptera so any comments regarding identification, etc., would be gratefully received. Click on the images to view at a larger size.

Southern Field Cricket Gryllus bimaculatus, the dominant sound in the nocturnal chorus around Vila do Corvo.
Southern Field Cricket Gryllus bimaculatus by darrylspittle

The blurred background trace on the spectrogram at approximately 4.5 kHz is the stridulations of competing males nearby. I'm pretty sure Large Conehead Ruspolia nitidula is responsible for the indistinct trace centred on approximately 15 kHz.

Large Conehead Ruspolia nitidula, identification slightly more tentative but see what you think.
Large Conehead Ruspolia nitidula by darrylspittle

The significantly higher frequency range produces a much less far-carrying and dominant sound (at least to human ears) as compared to Southern Field Cricket. Due to a former diving accident, presumably resulting in a ruptured tympanic membrane [Correction: the injury was a perilymph fistula - ouch!], at least one member of Team Corvo struggled to hear this at all.

Here's the identification of which I am least confident. I think, in between the barking of a dog displaying his displeasure at being awoken by a bloke creeping about with a Sennheiser MKH60, this might be Mediterranean Katydid Phaneropterus nana. Whaddya reckon?
Possible Mediterranean Katydid Phaneroptera nana by darrylspittle

And finally, the most obvious orthopteran on the island, Migratory Locust Locusta migratoria, they are everywhere: sitting on the roads, squashed on the roads, shagging on the roads,...

Aaah look, the big one is giving the little one a piggy-back.


Gareth said...

Hi Darryl
An interesting post. I had a quick listen to Ragge & Reynolds (Grasshoppers & Crickets of Western Europe), your id's sound correct to my ear. The last also known as Southern Sickle-bearing Bush-cricket. Helps that the Orthopteran fauna on Corvo seems, not unsurprisingly, quite limited (4sp?).

Cheers, Gareth

Darryl said...

Cheers for your input Gareth.
Since getting back I've invested in the Ragge & Reynolds book and CDs, I've been meaning to update this post with their English names, etc.

According to Borges et al. (2010) there are 4 spp. on Corvo, only 3 on Flores (bit odd) and 15 in total across the Azores. But new species are still being added to island lists (cf. Borges et al. 2005 with Borges et al. 2010).