Counts of caterpillars arising from a short-term experiment that installed lighting rigs in previously unlit areas to test for a change in nocturnal feeding behaviour. Caterpillars were counted from lit and control transects at two locations in Oxfordshire during January and February 2019. Lighting rigs were installed during the afternoon and switched on one hour before sunset. To give the nocturnal caterpillars time to become active, sampling occurred between 60 and 120 minutes after sunset. On a sampling night, all transects were sampled within a 5–10-minute period. Full details about this dataset can be found at https://doi.org/10.5285/7e7ce7c1-aa16-484f-86b1-90c5b088a64c
