Limits of vector calibration in the Australian desert ant, Melophorus bagoti
Desert ants that forage solitarily continually update their position relative to the nest through path integration. This is accomplished by combining information from their celestial compass and pedometer. The path integration system can adapt when memories of previous inbound routes do not coincide with the outbound route, through vector calibration. Here, we test the speed and limit of vector calibration in the desert ant Melophorus bagoti by creating directional conflicts between the inbound and outbound routes (45°, 90°, 135°, 180°). The homeward vector appears to calibrate rapidly after training with shifts occurring after three foraging trips, yet the limit of the vector’s plasticity appears to be a maximum of 45°. At 45° conflicts, the vector calibrates the full 45°, suggesting dominance of the previous inbound memories over the outbound cues of the current trip. Yet at larger directional conflicts, vector shifts after training diminish, with foragers in the 90° and 135° conditions showing smaller intermediate shifts between the inbound memories and the current outbound vector. When the conflict is at its maximum (180°), foragers show no calibration, suggesting the outbound vector is dominant. Panorama exposure during training appears to aid foragers orienting to the true nest, but this also appears limited to about a 45° shift and does not improve with training.
KeywordsAnts Path integration Vector navigation Vector calibration Memory
This research was supported by a Grant from the Australian Research Council (DP150101172) and many thanks to the Centre of Appropriate Technology for access to the field site and nests. The authors declare no conflict of interests in association with this work.
Experiments conceived and designed: CAF. Data collection and analysis: CAF. Manuscript production and revision: CAF and KC.
- Batschelet E (1981) Circular Statistics in Biology. New York: Academic PressGoogle Scholar
- Holm S (1979) A simple sequential rejective method procedure. Scand J Stat 6:65–70Google Scholar
- Mittelstaedt H (1983) The role of multimodal convergence in homing by path integration. Fortschr Zool 28:197–212Google Scholar
- Wehner R (1987) Spatial organization of the foraging behavior in individually searching desert ants, Cataglyphis (Sahara desert) and Ocymyrmex (Namib desert). In: Pasteels JM, Deneubourg JM (eds) From individual to collective behavior in insects. Birkhäuser, Basel, pp 15–42Google Scholar
- Wehner R (1994) The polarization-vision project: championing organismic biology. In: Schildberger K, Elsner N (eds) Neural basis of behavioural adaptation. Fischer, Stuttgart, pp 103–143Google Scholar
- Wehner R (2008) The architecture of the desert ant’s navigational toolkit (Hymenoptera: Formicidae). Myrmecol News 12:85–96Google Scholar
- Wehner R, Wehner S (1986) Path integration in desert ants. Approaching a long-standing puzzle in insect navigation. Monit Zool Ital 20:309–331Google Scholar
- Zar JH (1998) Biostatisical analysis, 4th edn. Engelwood Cliffs, New JerseyGoogle Scholar
- Zeil J, Ribi WA, Narendra A (2014) Polarization vision in ants, bees and wasps. In: Horváth G (ed) Polarized light and polarization vision in animal sciences, 2nd edn. Springer, Berlin, pp 41–60Google Scholar