Counting glowworms 13 July 2022

Five Barnsley Naturalists and one interested walker on the TransPennine Trail (TPT) joined Doug late in the evening of Wednesday 13 July in his twice weekly count of glowworms during the summer on the TPT near Thurgoland.

Both the glowworm numbers (11) and moth trap numbers (4) were however very low that night.

For more information on glowworms –

2 thoughts on “Counting glowworms 13 July 2022”

  1. Comment from Doug
    There was a full moon that night so I revisited an old school of thought about the lunar effect on insects. The last time I worked on this theory I tried to match the moon phase with glowworm numbers without success.

    This time I looked on the internet and there was the answer “Effect of moonlight on insect activity by CB Williams and BP Singh in Nature 167853 ( 1951) ” which states that in three successive years between May and October the catches in a light trap, both of Lepidoptera and of all insects together (chiefly Diptera) reached a peak at or shortly after a New Moon when the geometric mean catches were three to four times as great as those of a Full Moon.
    Why did I not think of this before? DOUG

    1. Doesn’t apply to moth trapping but would a full moon also make it more difficult to spot the light of the glowworms, assuming that they were glowing? Peter

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