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Cataglyphis

Cataglyphis is a genus of ant, desert ants, in the subfamily Formicinae. Its most famous species is C. bicolor, the Sahara Desert ant, which runs on hot sand to find insects that died of heat exhaustion, and can, like other several other Cataglyphis species, sustain body temperatures up to 50°C. Cataglyphis is also the name of an autonomous rover that won the NASA Sample Return Robot Centennial Challenge inspired by the navigation approaches used by desert ants.

Name

It was named in 1850, with reference to the impressions of its abdomen: "Von χατά und γλυψίς der Einschnitt. Eine Andeutung auf die vielen Einschnitte oder vielmehr Eindrücke de Hinterleibs."

Description

Species of this genus are behaviourally, morphologically, and physiologically adapted to dry and hot habitats.

Navigational behaviour

In the Sahara, ants live where no bushes or clumps of grass are available to protect them, and where tracks are covered by wind-blown sand in seconds. The midday sun is so hot that even the permanent residents, sand lizards, insects, and a few birds, have to take shelter, but this is when, for not much more than an hour, Cataglyphis spp. are to come out of their underground nests and forage. They can withstand higher temperatures than any other insects. They pour out on to the sand and search for insects that have died of heat stress. Each ant dashes about in zigzag patterns, but as soon as one is lucky enough to find a tiny insect corpse, it has to get it back to the nest quickly before the ant dies of the heat. It does not retrace the zig-zagging path of its outward journey; even if a scent trail made this possible, such a route would be time-wasting. Instead, it runs in a straight line directly back to its nest hole.

On its outward journey, it zig-zags right and left. Every time it changes direction, it lifts its head and wheels around to take a bearing on the sun. In addition, it has to remember how far it went on each straight run. When time to head for home, it has to sum all these data and come out with the precise direction needed. Some outward journeys take an ant a quarter of an hour, with sun sightings every few seconds.

In an experiment, individual ants were fitted with an apparatus that blocked direct sight of the sun, while giving a false impression of where the sun was, using a mirror. When these ants headed for home, they dashed off to a point in the desert displaced by just the amount that the mirror had shifted the sun's position.

Like ants in the Crematogaster genus, Cataglyphis workers can raise their gaster (abdomen) to a vertical position in an acrobat manner. This behavior may serve as a defensive gesture in Crematogaster (acrobat) ants, but in Cataglyphis this is thought to improve mobility in desert habitats.

Distribution

At least five different species of Cataglyphis occur in the Sahara Desert, which may be considered the center of distribution for this genus. Five species also occur in Israel. Some species reach into southern Russia, southern Spain, Greece, the former Yugoslavia, Hungary, the European part of Turkey, and the Aral-Caspian area near Tijanchan.

Parthenogenesis

Queen ants of the species C. cursor can produce female reproductive progeny (i.e. potential new queens or gynes) by parthenogenesis. Parthenogenesis, in this case, involves, a process (automictic thelytoky) by which two haploid products of meiosis fuse to form a diploid zygote that develops into a gyne. Queens can also produce female worker ants by sexual reproduction involving fertilisation of eggs.

Species

References

Further reading

  • Heusser, Daniel & Wehner, Rüdiger (2002): The visual centring response in desert ants, Cataglyphis fortis. The Journal of Experimental Biology 205: 585–590. Full HTML - PDF

External links