Nest Defense and Conspecific Enemy Recognition in the Desert Ant Cataglyphis fortis

AbstractDesert ants of the genus Cataglyphis are renowned for their navigation abilities, especially for their beeline homing after meandering foraging excursions reaching several hundreds of meters in length. A spiralling nest search is performed when an ant misses the nest entrance upon completing its homebound travel. We examined the nest search behaviours of two desert ant species dwelling in different habitats—Cataglyphis bombycina living in the dunes of the Sahara and Cataglyphis fortis found in the salt pans of North Africa. The two species show distinct differences in walking behaviour. C. bombycina performs a strict tripod gait with pronounced aerial phases, high stride frequencies, and extremely brief ground contact times. In view of these peculiarities and the yielding sand dune substrate, we hypothesised that homing accuracy, and namely distance measurement by stride integration, should be lower in C. bombycina, compared to the well-studied C. fortis with less specialised walking behaviour. We tested this hypothesis in ants’ homebound runs from a feeding site in a linear channel setup. Surprisingly, the accuracies of nest searches were similar in the two ant species, and search accuracy was also independent of the walking substrate, soft dune sand or a hard floor. The spread of the nest search, by contrast, differed significantly between the two species, C. bombycina exhibiting a larger search spread. This may be interpreted as an increased path integration uncertainty due to the above locomotor specialisations, or as a compensation strategy accounting for the silver ants’ particular environmental and behavioural situation.

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Discrimination of inclined path segments by the desert ant Cataglyphis fortis

Journal of Comparative Physiology A ◽

10.1007/s00359-012-0714-5 ◽

2012 ◽

Vol 198 (5) ◽

pp. 363-373 ◽

Cited By ~ 7

Author(s):

Sabine Wintergerst ◽

Bernhard Ronacher

Keyword(s):

Desert Ant ◽

Cataglyphis Fortis

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Lateral optic flow does not influence distance estimation in the desert ant Cataglyphis fortis

Journal of Experimental Biology ◽

10.1242/jeb.203.7.1113 ◽

2000 ◽

Vol 203 (7) ◽

pp. 1113-1121 ◽

Cited By ~ 16

Author(s):

B. Ronacher ◽

K. Gallizzi ◽

S. Wohlgemuth ◽

R. Wehner

Keyword(s):

Flow Field ◽

Optic Flow ◽

Visual Cues ◽

Food Source ◽

Motion Parallax ◽

Distance Estimation ◽

Desert Ants ◽

Desert Ant ◽

Walking Speeds ◽

Cataglyphis Fortis

The present account answers the question of whether desert ants (Cataglyphis fortis) gauge the distance they have travelled by using self-induced lateral optic-flow parameters, as has been described for bees. The ants were trained to run to a distant food source within a channel whose walls were covered with black-and-white gratings. From the food source, they were transferred to test channels of double or half the training width, and the distance they travelled before searching for home and their walking speeds were recorded. Since the animals experience different motion parallax cues when walking in the broader or narrower channels, the optic-flow hypothesis predicted that the ants would walk faster and further in the broader channels, but more slowly and less far in the narrower channels. In contrast to this expectation, neither the walking speeds nor the searching distances depended on the width or height of the channels or on the pattern wavelengths. Even when ventral-field visual cues were excluded by covering the eyes with light-tight paint, the ants were not influenced by lateral optic flow-field cues. Hence, walking desert ants do not depend on self-induced visual flow-field cues in gauging the distance they have travelled, as do flying honeybees, but can measure locomotor distance exclusively by idiothetic means.

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Flexible weighing of olfactory and vector information in the desert ant Cataglyphis fortis

Biology Letters ◽

10.1098/rsbl.2013.0070 ◽

2013 ◽

Vol 9 (3) ◽

pp. 20130070 ◽

Cited By ~ 10

Author(s):

Cornelia Buehlmann ◽

Bill S. Hansson ◽

Markus Knaden

Keyword(s):

Path Integration ◽

Food Sources ◽

Feeding Site ◽

Desert Ants ◽

Desert Ant ◽

Vector Information ◽

Pass Through ◽

Path Integrator ◽

Odour Plumes ◽

Cataglyphis Fortis

Desert ants, Cataglyphis fortis , are equipped with remarkable skills that enable them to navigate efficiently. When travelling between the nest and a previously visited feeding site, they perform path integration (PI), but pinpoint the nest or feeder by following odour plumes. Homing ants respond to nest plumes only when the path integrator indicates that they are near home. This is crucial, as homing ants often pass through plumes emanating from foreign nests and do not discriminate between the plume of their own and that of a foreign nest, but should absolutely avoid entering a wrong nest. Their behaviour towards food odours differs greatly. Here, we show that in ants on the way to food, olfactory information outweighs PI information. Although PI guides ants back to a learned feeder, the ants respond to food odours independently of whether or not they are close to the learned feeding site. This ability is beneficial, as new food sources—unlike foreign nests—never pose a threat but enable ants to shorten distances travelled while foraging. While it has been shown that navigating C. fortis ants rely strongly on PI, we report here that the ants retained the necessary flexibility in the use of PI.

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Multimodal Influences on Learning Walks in Desert Ants (Cataglyphis fortis)

10.1101/2020.04.17.046839 ◽

2020 ◽

Cited By ~ 1

Author(s):

Jose Adrian Vega Vermehren ◽

Cornelia Buehlmann ◽

Ana Sofia David Fernandes ◽

Paul Graham

Keyword(s):

Wind Direction ◽

Visual Information ◽

Visual Cues ◽

Sensory Information ◽

Novel Object ◽

Desert Ant ◽

Sensory Modalities ◽

The World ◽

Learning Walks ◽

Cataglyphis Fortis

AbstractAnts are excellent navigators taking into account multimodal sensory information as they move through the world. To be able to accurately localise the nest at the end of a foraging journey, visual cues, wind direction and also olfactory cues need to be learnt. Learning walks are performed at the start of an ant’s foraging career or when the appearance of the nest surrounding has changed. We investigated here whether the structure of such learning walks in the desert ant Cataglyphis fortis takes into account wind direction in conjunction with the learning of new visual information. Ants learnt to travel back and forth between their nest and a feeder, and we then introduced a black cylinder near their nest to induce learning walks in regular foragers. By doing this across days with different prevailing wind directions, we were able to probe how ants balance the influence of different sensory modalities. We found that (i) the ants’ outwards headings are influenced by the direction of the wind with their routes deflected in such a way that they will arrive downwind of their nest when homing, (ii) a novel object along the route induces learning walks in experienced ants and (iii) the structure of learning walks is shaped by the wind direction rather than the position of the visual cue.

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