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Smells like home: Desert ants, Cataglyphis fortis, use olfactory landmarks to pinpoint the nest.

Steck K, Hansson BS, Knaden M - Front. Zool. (2009)

Bottom Line: As a result of high temperatures and the unpredictable distribution of food, Cataglyphis ants do not lay pheromone trails.Apart from the visual cues within the ants' habitat, we found potential olfactory landmark information with different odour blends coupled to various ground structures.As Cataglyphis ants associate environmental odours with the nest entrance they can be said to use olfactory landmarks in the vicinity of the nest for homing.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans Knoell Strasse 8, 07745 Jena, Germany. mknaden@ice.mpg.de.

ABSTRACT

Background: Cataglyphis fortis ants forage individually for dead arthropods in the inhospitable salt-pans of Tunisia. Locating the inconspicuous nest after a foraging run of more than 100 meters demands a remarkable orientation capability. As a result of high temperatures and the unpredictable distribution of food, Cataglyphis ants do not lay pheromone trails. Instead, path integration is the fundamental system of long-distance navigation. This system constantly informs a foraging ant about its position relative to the nest. In addition, the ants rely on visual landmarks as geocentric navigational cues to finally pinpoint the nest entrance.

Results: Apart from the visual cues within the ants' habitat, we found potential olfactory landmark information with different odour blends coupled to various ground structures. Here we show that Cataglyphis ants can use olfactory information in order to locate their nest entrance. Ants were trained to associate their nest entrance with a single odour. In a test situation, they focused their nest search on the position of the training odour but not on the positions of non-training odours. When trained to a single odour, the ants were able to recognise this odour within a mixture of four odours.

Conclusion: The uniform salt-pans become less homogenous if one takes olfactory landmarks into account. As Cataglyphis ants associate environmental odours with the nest entrance they can be said to use olfactory landmarks in the vicinity of the nest for homing.

No MeSH data available.


Olfactory landmarks in the Cataglyphis habitat. A. Sample locations. B. Location-specific gas chromatographic profiles collected on consecutive days are displayed next to the corresponding photo. Dashed lines depict identified components that were used for EAG recordings. C. EAG responses of Cataglyphis to the identified components. Horizontal bars indicate the stimulus duration.
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Figure 1: Olfactory landmarks in the Cataglyphis habitat. A. Sample locations. B. Location-specific gas chromatographic profiles collected on consecutive days are displayed next to the corresponding photo. Dashed lines depict identified components that were used for EAG recordings. C. EAG responses of Cataglyphis to the identified components. Horizontal bars indicate the stimulus duration.

Mentions: Despite its homogenous appearance, the flat ground within the salt-pan habitat differs slightly in its soil structure. Covered by a continuous salt crust, the surface is occasionally interrupted by clefts or by pieces of wood and halophytic plants, signs of past periods of flooding (Figure 1A). In order to check whether these structures result in different habitat odours, we used gas chromatography to analyse headspace samples of continuous salt crust, cleft salt crust, wood and halophytic plants. The emitted volatiles for each sample were relatively constant over two consecutive days, whereas the chromatograms differed among the samples (Figure 1B). We identified five components (Figure 1C) that are known as common plant volatiles and tested them for EAG activity (Figure 1C). All components generated antennal responses. In summary, the microhabitat blends were stable over time, differed between samples, and could be detected by the ants. Hence, they present potential olfactory landmarks.


Smells like home: Desert ants, Cataglyphis fortis, use olfactory landmarks to pinpoint the nest.

Steck K, Hansson BS, Knaden M - Front. Zool. (2009)

Olfactory landmarks in the Cataglyphis habitat. A. Sample locations. B. Location-specific gas chromatographic profiles collected on consecutive days are displayed next to the corresponding photo. Dashed lines depict identified components that were used for EAG recordings. C. EAG responses of Cataglyphis to the identified components. Horizontal bars indicate the stimulus duration.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2651142&req=5

Figure 1: Olfactory landmarks in the Cataglyphis habitat. A. Sample locations. B. Location-specific gas chromatographic profiles collected on consecutive days are displayed next to the corresponding photo. Dashed lines depict identified components that were used for EAG recordings. C. EAG responses of Cataglyphis to the identified components. Horizontal bars indicate the stimulus duration.
Mentions: Despite its homogenous appearance, the flat ground within the salt-pan habitat differs slightly in its soil structure. Covered by a continuous salt crust, the surface is occasionally interrupted by clefts or by pieces of wood and halophytic plants, signs of past periods of flooding (Figure 1A). In order to check whether these structures result in different habitat odours, we used gas chromatography to analyse headspace samples of continuous salt crust, cleft salt crust, wood and halophytic plants. The emitted volatiles for each sample were relatively constant over two consecutive days, whereas the chromatograms differed among the samples (Figure 1B). We identified five components (Figure 1C) that are known as common plant volatiles and tested them for EAG activity (Figure 1C). All components generated antennal responses. In summary, the microhabitat blends were stable over time, differed between samples, and could be detected by the ants. Hence, they present potential olfactory landmarks.

Bottom Line: As a result of high temperatures and the unpredictable distribution of food, Cataglyphis ants do not lay pheromone trails.Apart from the visual cues within the ants' habitat, we found potential olfactory landmark information with different odour blends coupled to various ground structures.As Cataglyphis ants associate environmental odours with the nest entrance they can be said to use olfactory landmarks in the vicinity of the nest for homing.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans Knoell Strasse 8, 07745 Jena, Germany. mknaden@ice.mpg.de.

ABSTRACT

Background: Cataglyphis fortis ants forage individually for dead arthropods in the inhospitable salt-pans of Tunisia. Locating the inconspicuous nest after a foraging run of more than 100 meters demands a remarkable orientation capability. As a result of high temperatures and the unpredictable distribution of food, Cataglyphis ants do not lay pheromone trails. Instead, path integration is the fundamental system of long-distance navigation. This system constantly informs a foraging ant about its position relative to the nest. In addition, the ants rely on visual landmarks as geocentric navigational cues to finally pinpoint the nest entrance.

Results: Apart from the visual cues within the ants' habitat, we found potential olfactory landmark information with different odour blends coupled to various ground structures. Here we show that Cataglyphis ants can use olfactory information in order to locate their nest entrance. Ants were trained to associate their nest entrance with a single odour. In a test situation, they focused their nest search on the position of the training odour but not on the positions of non-training odours. When trained to a single odour, the ants were able to recognise this odour within a mixture of four odours.

Conclusion: The uniform salt-pans become less homogenous if one takes olfactory landmarks into account. As Cataglyphis ants associate environmental odours with the nest entrance they can be said to use olfactory landmarks in the vicinity of the nest for homing.

No MeSH data available.