Tuesday, 10 January 2017

Grey Shoulder-knot and moth trap results

The relatively mild night on Sunday (8th January) brought this individual out of hibernation. From the books this seems quite early.

I have also analysed my results from my simple experiment to compare trapping results using 2 different bulbs. A summary is included here. I have got a more detailed analysis with graphs. looking at time of year and species caught but I am not sure whether it is appropriate to share it here?

Throughout  2016 I attempted to find pairs of nights that were not more than a few days apart and with forecast weather conditions in terms of temperature, wind speed and rainfall as similar as possible.  On one of the two nights I would run my Robinson trap with a standard 125W MV bulb and on the other night I ran the same trap in the same place but with a 20W Blacklight bulb.

In total 35 pairs of results were obtained.

A summary of the results is given below.

125W MV
20W Eco
Total number of moths caught
Mean number of moths per night
Mean number of species per night
Total number of different species caught
Number of species not caught with other bulb

Andy Newbold, Sibford Ferris, Oxon


  1. Hi Andy, there's no problem at all adding your comparison results here, however detailed they might be! It is in the interests of all of us that we learn more about other bulb types now that the days of 125wt MV seem to be numbered.

    You will have noticed, though, that Blogger can be a little bit fussy about displaying charts, graphs, etc so it may take a bit of trial and error to get things to appear as you would want them (try using the 'preview' feature before uploading). It has no real problem with pictures so if you can somehow save any charts, graphs, etc as jpegs that might prove easier.

  2. I think these results are very interesting. Is the 'blacklight' one that just gives off uv or is it one of those which the makers call blacklight, but it glows more like an actinic?
    If you can get the breakdown onto the site, then that would be interesting, too. There is, of course, a long-running debate about whether different lights attract different moths, not just different numbers.

    1. I will attempt to get a fuller breakdown of the results onto the site. The bulb used was the 'Eco' bulb supplied by Watkins and Doncaster which gives off a visible purple light as well as presumably a lot of UV. My initial impression is that in my results there is little evidence of different moths being attracted to the different bulbs but it is a rather small set of data. I will give more details when I report the results more fully.


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