[Rockhounds] colour perception, organic fluorescence, etc

[Carol J. Bova]

As Axel wrote, scorpions are highly fluorescent. I was looking for  
chalcedony near Blythe,  California one year using a little UV lamp,  
to see if it helped me with finding fire agate nodules (which often  
have a chalcedony "cap"). The chalcedony fluoresces a brilliant lime  
green (green-yellow), and I discovered, so do scorpions. Thus ended my  
plans for night time rockhounding for fire agate.

I found a reference in a 2006 journal article of a 2001 study, that  
marking insects with fluorescent dusts to track the movements of  
insects in orange groves was a reliable method,

Without looking much further, I noticed there are other studies with  
both insects and rats in orange groves, so it's a successful method.  
The fluorescent powder allows observations of insect/animal activity  
in the dark. (Searched on fluorescence insects orange trees.)
Carol
Authors: Coviella, Carlos E.; Garcia, Juliana F.; Jeske, Daniel R.;  
Redak, Richard A.; Luck, Robert F.
Source: Journal of Economic Entomology, Volume 99, Number 4, August  
2006 , pp. 1051-1057(7)
Publisher: Entomological Society of America

http://www.ingentaconnect.com/content/esa/jee/2006/00000099/00000004/art00004?crawler=true
Abstract
"A mark-release-recapture technique was developed and tested for use  
in tracking the field movements of adult glassy-winged sharpshooters,  
Homalodisca coagulata (Say) (Hemiptera: Cicadellidae), in various  
agricultural and urban plantings. Greenhouse experiments in which  
adult H. coagulata were marked with one of five colored fluorescent  
dusts (Aurora Pink-A11, Horizon Blue-A19, Blaze Orange-A15N, Saturn  
Yellow-A17, and Corona Magenta-A21) and released into cages with  
citrus seedlings showed that their mortality rates during a 30-d  
period were statistically similar to that of the undusted controls."
"... The use of colored dusts to mark H. coagulata proved to be  
reliable, cost-effective, and time-efficient for mark-release- 
recapture studies with this insect within a citrus grove, but they are  
less likely to be useful for studies of adult H. coagulata movements  
among plantings."


On Dec 14, 2008, at 3:01 AM, Horst Windisch wrote:

> Hi all,
>
> Many years ago, some botanists ap[proached me to lend them a  
> portable long
> wave UV lamp. They were going to check for insects on orange trees,  
> which
> were affecting the orange trees. Cannot remember the results.  
> Anybody heard
> of this before?
>
> Regards,
>
> Horst
>
> ----- Original Message ----- From: "J. R. Hodel" <jr50wv at yahoo.com>
> To: <rockhounds at lists.drizzle.com>
> Sent: Saturday, December 13, 2008 4:11 AM
> Subject: [Rockhounds] colour perception, organic fluorescence, etc
>
>
> HI Axel, Kitty, et al:
>
> Someone remarked about color perception, and this not only varies  
> between
> people but between eyes. Now I'll date myself . . . Back in the day  
> when I
> spent a lot of time in a darkroom and comparing color results from  
> film
> batch to batch, and from video camera to video camera despite the  
> best job
> the color engineers could do, I noticed that my eyes had slightly  
> different
> color responses. Partly this was noticable because back then you  
> aimed a
> film camera with one eye at the viewfinder.
>
> One eye was closer to Ektachrome and one was closer to Kodachrome - go
> figure. It's less noticable now, but still there. So comparing  
> colors of
> phosphorescence and fluorescence with the naked eye and discussing  
> it via
> email may be futile. Surely the color business has sensors that make  
> this
> all objective nowadays?
>
> Axel, here in the North American forests we have several woods that
> fluoresce under the right stimulation. Locust (I think the black  
> locust
> variety native to the WV forest) glows, as does the shrub sumac.  
> This isn't
> the poison sumac which I think is a western shrub, this is a shrub  
> which
> bears bright red fruit clusters with which you can make a pleasent
> non-intoxicating beverage. It glows best in long-wave "black light".  
> I don't
> remember which spectrum locust responds to best.
>
> Do we know what mechanism might cause the fluorescent reaction in  
> organic
> materials?
>
> Just wondering, sorry if we're off topic, but it is related to black  
> light,
> etc.
>
> Merry Christmas, everyone!
>
> JR
>
>
>
>
>
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