Night collecting

[ernst neering]

Dear Andres, 

Re your question to all:

>Even in full moon nights, is there still a chance
>for good results if one waits until the moon hides behind any obstacle,
>like a mountain? What about trying inside a deep forested river canyon?
>Maybe I should ask an astronomer, but how many hours is a full moon
>up in the sky (say the dawn and twilight of the moon, as it is with
>the sun)? 
>I'd like to remind the readers that my area is in a tropical country
>and things should be a little different here.
>Andres Orellana
>Merida, Venezuela

and the answer by Chris, I would like to add that the best time is after rain 
on warm nights at new moon. I collected extensively in Suriname and operated 
a lighttrap at full and at new moon over a period of over a year. The numbers 
per species varied but often were low so I could not make a statistical 
analysis. (My collection is partly at CELOS, Suriname, partly at Wageningen 
University, the Netherlands) Besides I could not record cloudcover during the 
full night, which is necessary to study the influence of direct or indirect 
moonlight. At full moon I often collected good numbers if it had rained early 
in the night and it remained overcast later on: warm and damp.
In Venezuela there must be information on this matter as I know that 
Universidad Central de Venezuela at Maracay has operated lighttraps in Rancho 
Grande reserve for years. I do not know who is still there, the authority in 
the eighties was Prof Fernandez Yepez. In Merida maybe Dr Pedro Salinas may 
help you. Is he still at MAC-ULA? He may remeber me as 'cafe negro grande', I 
visited him in 1975 and tried to meet him in 1983 but he was out then.
Usefull information can be found in the work of Bowden:
	Bowden-J. 1973. The influence of moonlight on catches of insects in 
light-traps in Africa. Part I. The moon and moonlight. 
Bulletin-of-Entomological-Research 63 (1): 113-128.
	Bowden-J; Church-BM. 1973. The influence of moonlight on catches of 
insects in light-traps in Africa. Part II. The effect of moon phase on 
light-trap catches. Bulletin-of-Entomological-Research 63 (1): 129-142.
	Bowden-J; Morris-MG. 1975. The influence of moonlight on catches of 
insects in light traps in Africa. Part III. The effective radius of a 
mercury-vapour light-trap and the analysis of catches using effective radius. 
Bulletin-of-Entomological-Research 65 (2): 303-348.
	Bowden-J; Gibbs-DG. 1973. Light-trap and suction-trap catches of 
insects in the northern Gezira, Sudan, in the season of southward movement of 
the Inter-Tropical Front. Bulletin-of-Entomological-Research 62 (4): 571-596.
	Bowden-J. 1973. The significance of moonlight in photoperiodic 
responses of insects. Bulletin-of-Entomological-Research 62 (4): 605-612.
	Bowden-J. 1982. An analysis of factors affecting catches of insects 
in light-traps. Bulletin-of-Entomological-Research 72 (4): 535-556.
	Bowden-J. 1981. The relationship between light- and suction-trap 
catches of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae), and the 
adjustment of light-trap catches to allow for variation in moonlight. 
Bulletin-of-Entomological-Research 71 (4): 621-629.
	Perry-JN; Bowden-J. 1983. A comparative analysis of Chrysoperla 
carnea catches in light- and suction-traps. Ecological-Entomology 8 (4): 
383-394. 
	Bowden-J. 1984. Latitudinal and seasonal changes of nocturnal 
illumination with a hypothesis about their effect on catches of insects in 
light-traps. Bulletin-of-Entomological-Research 74 (2): 279-298.
	Bowden-J; Mukhopadhyay-S; Nath-PS; Sarkar-TK; Sarkar-S; 
Mukhopadhyay-S. 1988. Analysis of light-trap catches of Nephotettix species 
(Hemiptera: Cicadellidae) in West Bengal. 
Indian-Journal-of-Agricultural-Sciences 58 (2): 125-130.

Expect good numbers of Saturnids, Sphingids (I had over 50 species in one 
rainforest location!), Noctuids, Lymantriids, Geometrids, Arctiids and many 
small ones like Pyralids, Oecophorids, Gelechiids etc.
I am particularly interested in Ctenuchids, the day flying moths which in the 
tropics fly at night.... Do not forget to record the altitude of your 
collection sites. It would be marvellous to collect at the different stations 
of the teleferico: up to 5000 meters (Pico Bolivar) above sealevel! In the 
lower forest beware of rhinoceros beetles and other large beetles which are 
not stunned easily and trample over your moths. Also beware of ants pulling 
out the moths from the collection jar. This happened sometimes in Suriname at 
the end of the night, when the ethylacetate I used had mostly evaporated.
If you collect on cloth it is different of-course. You may try what comes on 
a smear made of sugar and dark brown beer. Textbooks will help you with 
receipes.

Success!

Ernst Neering
Harnjesweg 45
Wageningen
The Netherlands