Myrmecochory

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Ant transporting a fruit that is normally anemochoric (presumably an achene )

The myrmecochory (ants spread), also myrmecochory or Myrmechorie (μύρμηξ of Greek, μύρμηκος, (Myrmex, genitive: mýrmēkos) "ant" and χωρεῖν (chōrein) "spread"), a propagation mechanism of plants, which ants to transport the Diaspores (fruits, seeds or spores) served. Numerous spring bloomers use this mechanism of propagation. The myrmecochory is a sub-form of the zoochory that often occurs in conjunction with other strategies of dispersion. Many violets and pansies use the ballochorie , the explosive scattering of seeds, first, trusting ants to carry their seeds further away.

Myrmecochory is particularly widespread in herbaceous forest plants in the northern hemisphere, but also occurs in the tropics. Over 3000 plant species are known to use this form of distribution. The myrmekochore plants include the snowdrop , liverwort , celandine , spring Adonis and even woody plants such as box and broom . The wild strawberry is partially spread myrmekochor, it provides the ants become their sweet fleshy flower bottoms that are as Earth " berries knows" where the nutlets are embedded.

Elaiosomes

Viola chelmea diaspores consist of hard-shelled seeds and attached elaiosomes

The diaspores of myrmekochoren plants have a nutrient-rich appendage, an elaiosome , as an attractant and nutrient body. The elaiosome is intended for consumption only. Ants carry the diaspores into their burrow due to their elaiosome appendages, where they separate the elaiosome from the diaspore. What happens next depends on the nature of the diaspore and the type of ant. The seeds of the palisade milkweed, for example, do not offer a point of attack for small ant species after the elaiosome has been eaten off and remain in the nest. The seeds of the holly buckthorn, on the other hand, have "handles" and can therefore be easily transported out of the nest. In many cases, the ants deposit the seeds as waste in the immediate vicinity of the nest on a "garbage dump". The advantage of such a way of spreading is on the one hand a well fertilized and protected germination place, on the other hand the seed is usually injured when the elaiosome is eaten off and thus germination is facilitated.

Ingredients of the elaiosomes

Myrmecochore elaiosomes (plants that ants use to spread their seeds) contain especially fats and sugar, and occasionally vitamin B, vitamin C, starch and protein, with sugar being particularly important for ants. Fischer u. a. pointed out that the elaiosomes are particularly nutritious for ants. Several authors have found oleic acids in eliosomes , which particularly encourage ants to collect. Bresinsky , for example, showed that the elaiosomes of some plants contain ricinoleic acid , which has also been found in ant larvae of the glossy black wood ant . In an experiment Brezinsky was able to show that this volatile substance triggers a true collecting instinct in workers of the glossy black wood ant: Schnitzel soaked in ricinoleic acid were eagerly carried into the nest. The elaiosome of the fragrant violet contains 1,2-diolein , which triggers a similar behavior in the ant species Aphaenogaster rudis .

Seed dispersal

The liverwort is one of the myrmekochoren plants

Seeds and fruits with elaiosomes are carried over long distances. Sernander observed the spread of a seed over a distance of 70 m. He calculated that a state of the red wood ant spreads 36,000 seeds annually. Whitney in Australia observed significantly more carry-overs. The ant Iridomyrmex viridiaeneus abducted Wattleseed up to 180 m, m, on average, however, the 94th

Influence of myrmecochory on ecosystems

How sensitive ecosystems are to myrmecochory can be seen in the invasion of the Argentine ant Linepithema humile in North America and South Africa, where it displaces native species of ants. Carney, Byerley and Holway report that the spread of the relatively large seeds of the myrmekochor poppy family Dendromecon rigida near the coast of San Diego is severely impaired because the Argentine ant does not spread the seeds, but the native ant species Pogonomyrmex subnitidus , which has so far spread the seeds had taken over, pushed back. Christian reports a similar story from South Africa: the plant communities of the bushland are being changed because the large seeds of the Argentine ant are not spread.

Development history

According to Bresinsky, the development of the myrmecochory is derived from the ornithochory , the spread of seeds by birds. Originally, plants in the tropical forests developed large elaiosomes, which were supposed to encourage birds to spread the seeds. The adaptation of the plants to the temperate zone required a strong reduction in the reproductive parts of the plant. But this made ornithochory impossible and ants took over the distribution.

Myrmecochory and ghosts

The eggs of some ghosts are strikingly similar to seeds with elaiosomes. Like eliosomes , the eggs developed so-called capitula , which exert the same force of attraction on ants. The South African ghost insect Phalces coccyx is common in the heathland of the Eastern Cape Province , where myrmekochore plants predominate. Ants do not distinguish between elaiosomes and capitula and carry seeds and eggs in the same way into their nests, where the capitula are eaten in the same way as the elaiosomes without damaging the eggs.

literature

  • Andreas Bresinsky: Structure, development history and ingredients of the elaiosomes. Studies on the myrmekochoren distribution of seeds and fruits . Schweizerbart Verlag. Stuttgart 1963. (Bibliotheca Botanica, issue 126)
  • Elena Gorb, Stanislaw Gorb: Seed Disposal by Ants in a Deciduous Forest Ecosystem: Mechanisms, Strategies, Adaptations. Kluwer Academic Publishers, Boston 2003, ISBN 1-4020-1379-5
  • Ursula Hoffmann and Michael Schwerdtfeger: ... and the golden tree of life, pleasure trips and educational trips in the realm of plants. Ulrich Burgdorf Verlag, Göttingen 1998, ISBN 3-89762-000-6 .
  • Angelika Lüttig & Juliane Kasten: Rose hip & Co - flowers, fruits and spread of European plants. Fauna Verlag, Nottuln 2003, ISBN 3-93-598090-6
  • Susanne Bonn and Peter Poschlod: Propagation biology of the plants of Central Europe. Quelle and Meyer 1998, ISBN 3-494-02242-9 .
  • Peter Leins and Claudia Erbar: Blossom and Fruit. E. Schweizerbart´sche Verlagbuchhandlung, Stuttgart 2008, ISBN 978-3-510-66046-9 .
  • Bernhard Seifert: The ants of Central and Northern Europe. Lutra-Verlag, Görlitz 2007, ISBN 978-3-936412-03-1 .

Individual evidence

  1. ↑ Bernhard Seifert : The ants of Central and Northern Europe. Lutra-Verlag, Görlitz 2007, ISBN 978-3-936412-03-1 , pages 66-68.
  2. ↑ Elena Gorb, Stanislaw Gorb: Seed Disposal by Ants in a Deciduous Forest Ecosystem: Mechanisms, Strategies, Adaptations. Kluwer Academic Publishers, Boston 2003, ISBN 1-4020-1379-5 , introduction.
  3. ↑ Crisanto Gómez, Xavier Espadaler and Josep M. Bas: Ant behavior and seed morphology: a missing link of myrmecochory. In: Oecologia. Volume 146 (2), 2005, pages 244-246, doi : 10.1007 / s00442-005-0200-7 .
  4. ↑ see Bresinsky, page 29.
  5. ^ Renate C. Fischer, Andreas Richter, Franz Hadacek and Veronika Mayer: Chemical differences between seeds and elaiosomes indicate an adaption to nutritional needs of ants. In: Oecologia. Volume 155 (3), 2008, pages 539-547, doi : 10.1007 / s00442-007-0931-8 .
  6. ↑ DI Marshall, AJ Beattie and WE Bollenbacher: Evidence for diglycerides as attractants in ant-seed interaction. In: Journal of Chemical Ecology. Volume 5 (3), 1979, pages 335-344, doi : 10.1007 / BF00987919 .
  7. ^ R. Sernander : Draft of a monograph of the European Myrmecochores. In: K. svenska vet.-akad. Handl. Volume 41, 1906, pages 1-410.
  8. ^ Quoted by Bresinsky, page 22.
  9. ↑ Kenneth D. Whitney: Dispersal for distance? Acacia ligulata seeds and meat ants Iridomyrmex viridiaeneus. In: Australia Ecology. Volume 27 (6), 2002, 589-595, doi : 10.1046 / j.1442-9993.2002.01216.x .
  10. ↑ SE Carney, MB Byerley and DA Holway, DA: Invasive argentine ants (Linepithema humile) do not replace native ants as seed dispersers of Dendromecon rigida (Papaveraceae) in California USA. In: Oecologia. Volume 135, 2003, pages 577-582, doi : 10.1007 / s00442-003-1200-0 .
  11. ↑ Caroline E. Christian: Consequences of a biological invasion reveal the importance of mutualism for plant communities. In: Nature . Volume 413, 2001, pages 635-639, doi : 10.1038 / 35098093 .
  12. ↑ see Bresinsky, page 22.
  13. ↑ SG Compton and AB Ware: Ants disperse the elaiosome-bearing eggs of an African stick insect. In: Psyche. Volume 98, Issue 2-3, 1991, pages 207-213, doi : 10.1155 / 1991/18258 .