Comparison of the movement speed of three ant (Hymenoptera: Formicidae) species along trails

Abstract

The aim of this study was to compare the speed of movement of 3 species of ants (Formica rufa, F. polyctena, and Lasius fuliginosus) along trails with different types of substrates. The study took place from June to August 2022 within the Holosiyivo Forest, located in Kyiv, Ukraine. For L. fuliginosus, the study was conducted in August and September 2022. For the experiment, 3 colonies of each species were selected in June, with only 3 trails passing on substrate (a total of 9 trails). One of the trails was left unchanged (ground surface), smooth logs were laid on the second and bark on the third. The movement speeds of the ants were measured for each substrate type (s/10 cm) by examining the individual trajectories of each worker (4678 in total). When the highway trajectory did not coincide with the trail and followed the shortest path instead, the ants did not cross the highway or crossed it only in some sections. In August 2022, all of the highways were relaid after the trail trajectories were recorded. Within a week or a week and a half, the ants switched completely to the highways. Larger-sized ant species (F. rufa, F. polyctena) moved 1.6 to 1.9 times faster than the smaller ones (L. fuliginosus) across all of the substrate types. For one of the species, the movement speeds differed between the different substrate types. F. rufa moved 62% slower on the ground surface than on logs, F. polyctena 50% slower, and L. fuliginosus 61% slower. Of the 3 substrate types, the ants preferred logs on highways the most. Ant movement on the logs was in all cases associated with the maximum speed, at 38%-50% faster than on the ground surface. While the F. rufa workers transported a similar amount of food per unit of time on both the bark and the ground surface, they transported 1.75 times more food on the logs than on the ground surface and 1.15 times more than on the bark. For F. polyctena, the highest amount of food transported on the logs was slightly less than that on the bark (1.13 times) and the lowest on the ground surface (4.15 times less than on the logs and 3.64 times less than on the bark). The usage of highways accelerates colony growth and artificially creates a nest site by improving trail infrastructure. Future studies should compare the growth rate of nest mounds over time in colonies of red wood ants with and without artificial trail networks