Effects of nocturnal celestial illumination on high-flying migrant insects

Radar networks hold great promise for monitoring population trends of migrating insects. However, it is important to elucidate the nature of responses to environmental cues. We use data from a mini-network of vertical-looking entomological radars in the southern UK to investigate changes in nightly abundance, flight altitude, and behaviour of insect migrants, in relation to meteorological and celestial conditions. An abundance of migrants showed positive relationships with air temperature, indicating that this is the single most important variable influencing the decision to initiate migration. In addition, there was a small but significant effect of moonlight illumination, with more insects migrating on full moon nights. While the effect of nocturnal illumination levels on abundance was relatively minor, there was a stronger effect on the insects’ ability to orientate close to downwind: flight headings were more tightly clustered on nights when the moon was bright and when cloud cover ..., Two vertical-looking insect radars (VLRs) located at three sites in southern England between 2000 and 2009 collected insect abundance and flight behaviour data. One VLR was located at Rothamsted Research, Harpenden, Hertfordshire, for the whole 10-year period. The other VLR was at Malvern, Worcestershire, from 2000 to 2003 and then at Chilbolton, Hampshire, from 2004 to 2009. All statistical analyses were conducted in the R software environment (version 3.6.3)., , # Effects of nocturnal celestial illumination on high-flying migrant insects

[https://doi.org/10.5061/dryad.sn02v6xb5](https://doi.org/10.5061/dryad.sn02v6xb5)

## Description of the data and file structure

In our research, we use data from a mini-network of vertical-looking entomological radars in the southern UK to investigate changes in nightly abundance, flight altitude, and behaviour of insect migrants in relation to the celestial conditions. This upload database contains three data files involved in the study; each data file corresponds to a section of the analysis, including the impact of the moonlight illumination on the number, flying height, and headings of the large and small migratory insects.

Dataset1: **analysis of number vs variables.csv**

It contains four sheets:

'large_spring': the related number analysis parameters for large insects in spring

'large_autumn': the related number analysis parameters for large insects in autumn

'med_spring': the related number ana...