Similarities and differences in path integration and search in two species of desert ants inhabiting a visually rich and a visually barren habitat

Abstract

Two species of Australian desert ants, one inhabiting a visually rich environment (Melophorus bagoti) and one inhabiting a visually barren environment (as yet unnamed and dubbed Melophorus sp.), were tested on path integration and subsequent search. For each species, prominent landmarks were placed near the nest, and ants were trained to visit a feeder. After training over 2 days, an ant was captured at the feeder when it had grabbed some food and tested, just once individually, in homing with the training landmarks either present or absent. Their subsequent search was also recorded on gridded paper according to a grid marked at the test site. Both species headed initially in the feeder-nest direction, but directional scatter was larger when training landmarks were absent. Melophorus bagoti ran a shorter distance before starting to search on tests with the landmarks absent, but Melophorus sp. ran a similar distance in both conditions. In both species, the variance in distance run was larger when landmarks were absent. In searching, both species expanded their search pattern more when landmarks were absent than when landmarks were present. Contrary to predictions, the distribution of the lengths of search segments was best described as a single exponential function on tests with landmarks absent and as a double exponential function with landmarks present. Show more