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Tibicen linnei
Thanks. I'll have to remember to post a video recording this summer once they start announcing their presence.
linnei vs. pruinosus ... Good question!
and my call is a "gut feeling"
It may not be possible from pic's alone. Certainly even with regards to some specimens in hand the traits overlap tremendously. Regarding color, not always diagnostic - but there may be a rule of thumb...linnei is ususally more of a "forest green / blue-green" than a "yellow/pea green" as in pruinosus - but not an ABSOLUTE. Across parts of Illinois - id is a mess...color, morphology, even call..all break down.
The only answer I can give you ...is experience with these across the range. In this particular image, the pattern to the mesonotum (black separating the lateral fulvous patches from the central green area) is less complete and delineated than "typical" of linnei. The abdomen is also looks less glossy than "typical" of linnei and the insect seems a bit more robust on the short axis. The males of both taxa have paired white spots at the base of the abdomen, but these are usually slightly larger in pruinosus - kinda like seen here - but not absolute.
Another key to answering this question may lie in the locality and what you hear. Do you hear pruinosus or linnei?....or maybe something in between???
Although not yet published or even substantiated genetically, linnei and pruinosus seem to cross! The morphologies and skewed calls exhibited by some populations also help support these hypotheticals and observation. Unfortuantely, the DNA profiles are so similar coupled with numat contamination it may take a while to determine for certain what is really going on with these.
a couple quick pic's
linnei
http://bugguide.net/node/view/233544
http://bugguide.net/node/view/602926/bgi...
pruinsous
http://bugguide.net/node/view/436993/bgi...
And after all is said and done - I might be wrong in this case ;)
There are a couple contacts in Illinois with whom I communicate each season regarding cicadas. Mapping linnei and pruinosus and the intermediates across this region is tough but progressing. The diagnostic traits are not absolute, but do seem "to cling to tendencies".
cheers,
bill
Thanks Bill. How do i tell Pruinosus from Linnei? It looks like Linnei are a darker shade of green, but it's difficult to tell using bugguide.
This cicada occupies an area of interest and may well be "linnei"! Several of us have been looking at cicadas in Illinois over the last several years. Although not yet verified genetically, we strongly suspect a lot of hybridization between and among pruinosus, linnei and canicularis to the north. We have been referring to them as the "Green Group".
In south & central Illinois, most populations seem to more closely adhere to pruinosus in call and morphology (often with some linnei-like traits). In the Bethany area and in other scattered isolates, there are some ambiguous populations with calls & morpholigical traits ranging from typical linnei to pruinosus and everything in between.
Refer here for details
pruinosus - http://bugguide.net/node/view/6967
linnei - http://bugguide.net/node/view/32143
Ambiguous taxa - http://bugguide.net/node/view/586797
Spotted on Aug 2, 2011
Submitted on Jul 24, 2011
