Date: Tue, 22 Apr 1997 19:54:14 +0200 From: v3andesp@ulmo.stud.slu.se (Anders Espef\dlt) To: cp@opus.hpl.hp.com Message-Id: <aabcdefg1579$foo@default> Subject: Catching insects by jamming their navigation
In cp digest 1056 Laurent wrote:
>The best in this strange method, is that uncatched flies, feeling safe,
>quickly fly again to the lamp and fall again, one, two, three times ! Very=
a
>few chances to escape from our diabolic trap !
Hello LISTeners,
This is not directly by cp but i hope that some people on this list will
appreciate it anyway. It=B4s about insects flying in the nigt.
The flies feelings don=B4t matter becase this trap is working by jamming
the insects navigation system. You see, the insect navigate by measuring the
angle to the moon. They then fly in a straight line by keeping the angle to
the moon constant. When they get so close to the lamp that it=B4s light
exceeds that of the moon they will use the lamp instead. BUT, when they fly
on, the angle to the lamp will change and they will have to compensate by
turning. This will make them circle around the lamp. Of course only the ones
(50%?) that initially decides to fly in some direction against the lamp
(moon) will approach the lamp. The other half will in a similar way circle
the lamp while getting further away, although we will not easily see this
because they do it far away.
This fenomenon is most intresting to watch, especially if you use a
strong light which will allow you to see bugs far away( 30 metres). Then you
will see that they dont fly straight towards the light, but around it, while
turning towards it and getting closer. To get the best effect you should use
a white light which is more like the light from the moon
That=B4s why the flies don=B4t escape, they might try, but they will=
escape
towards it. I also think that they hardly see the light as anything
dangerous, because in their natural world it isn=B4t.
I have been told this by a Danish entomologist who I met in Kakum, Ghana.
He was studying moths and I, curius as always, asked him how it works. Thank
you for your time and I hope I have increased the knowledge about this and
maybe stimulated someone=B4s interest in insects.
By the way, I have a terrarium with a VFT, Sarr and another cp that I
dont remember the english or latin name for, but in Swedish it=B4s "Tatort".
(Sorry for the English spelling, fellow scandinavians, with this spelling it
has several meanings I know, but you will sort it out). As I know I don=B4t
have any problems with them, but I don=B4t know yet what to expect from them
either.
Best regards,
Anders Espefalt, Student of Veterinary Medicine (not entomology)
v3andesp@ulmo.stud.slu.se
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