North African desert ants, Cataglyphis, use path integration to calculate a home vector during their foraging trips, constantly informing them about their position relative to the nest. This home vector is also used to find the way back to a productive feeding site the ant has encountered and thus memorized. When the animal fails to arrive at its goal after having run off the home or food vector, a systematic search is initiated. The basic search strategies are identical for nest and food searches, consisting of a search spiral superimposed by a random walk. While nest searches have been investigated in much detail, food site searches have received comparatively little attention. Here, we quantify and compare nest and food site searches recorded under similar conditions, particularly constant nest–feeder distance, and we observe notable differences in nest and food search performances. The parameters of nest searches are relatively constant and improve little with experience, although those small improvements had not been recognized previously. Food searches, by contrast, are more flexible and cover smaller or larger areas, mainly depending on the reliability of food encounter over several visits. Intriguingly, food site searches may be significantly more focussed than nest searches, although the nest should be the most important goal in an ant’s life. These results demonstrate both adaptability and high accuracy of the ants’ search programme.
Desert ant CataglyphisNavigation Systematic search Food search Nest search
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We thank Kathrin Judith Schwannauer for precious help with the field experiments and Ursula Seifert for editing the text. Andrea Wirmer deserves special thanks for advice with statistical analyses. We are grateful to Ken Cheng and two anonymous reviewers for comments that improved the manuscript. Infrastructural support was provided by the University of Ulm. Financial support was provided for an initial part of this study by the Deutsche Forschungsgemeinschaft (WO466/9-1) and the Volkswagen-Stiftung (I 78 580) through Grants to HW. This work forms part of the Ph.D. dissertation by Sarah E. Pfeffer.
Conflict of interest
The authors declare that they have no competing interests, financially or otherwise.
All experiments comply with the current laws in both Tunisia and Germany, particularly with regard to animal welfare.
Bolek S, Wittlinger M, Wolf H (2012b) What counts for ants? How return behaviour and food search of Cataglyphis ants are modified by variations in food quantity and experience. J Exp Biol 215:3218–3222PubMedCrossRefGoogle Scholar
Cheng K, Narendra A, Wehner R (2006) Behavioral ecology of odometric memories in desert ants: acquisition, retention, and integration. Behav Ecol 2:227–235Google Scholar
Cheng K, Narendra A, Sommer S, Wehner R (2009) Traveling in clutter: navigation in the Central Australian desert ant Melophorus bagoti. Behav Process 80:261–268CrossRefGoogle Scholar
Collett M, Collett T (2009) Local and global navigational coordinate systems in desert ants. J Exp Biol 212:901–905PubMedCrossRefGoogle Scholar