Camera transects as a method to monitor high temporal and spatial ephemerality of flying nocturnal insects

1. The current global decline of insects will have profound cascading effects as insects serve numerous roles in ecosystems. Effective but simple methods are needed to describe spatial and temporal distribution of flying insects in detail. This applies especially to important but short-lived phenomena such as insect swarms.
2. We developed, tested and implemented a non-invasive unbiased method with camera transects to measure spatio-temporal fluctuations in the abundance of nocturnal flying insects in different habitats. To test the sensitivity of the method we then tested for the influence of environmental factors on this abundance.
3. Our results show that the method is useful for the temporal and spatial comparison of insect abundances. Astonishingly, over 90% of the 63180 photos lacked insects. We found profound differences in insect abundance and dynamic changes between the studied habitats. Photos with large numbers of insects were rare, but occurred predominantly during the war...