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Elaiosome Structure:
– Fleshy structures attached to plant seeds
– Rich in lipids and proteins
– Attract ants for seed dispersal
– Develop from various seed or fruit tissues
– Present in 11,000 to 23,000 plant species

– Term for seed dispersal by ants
– Ants carry seeds to their nest
– Feed elaiosome to ant larvae
– Seeds germinate in nutrient-rich areas
– Symbiotic relationship benefiting plants and ants

– Evolutionary Significance:
– Example of convergent evolution in plants
– Elaiosomes serve the common function of attracting ants
– Various origins and pathways for elaiosome development
– Capitulum in stick insect eggs serves a similar purpose
– Mutualistic relationship in myrmecochory

– References:
– Gorb, E. & Gorb, S. (2003) on seed dispersal by ants
– Lengyel, Szabolcs et al. (2010) on convergent evolution of seed dispersal by ants
– Studies on phylogeny and biogeography in flowering plants
– Published in Perspectives in Plant Ecology, Evolution and Systematics
– Research on ant-mediated seed dispersal in ecosystems

– External Links:
– Access to detailed information on elaiosome
– Source discussing ant dispersal of seeds
– Retrieved from Wikipedia
– Categories include fruit morphology and insect ecology
– Contains Ancient Greek text and webarchive links

Elaiosome (Wikipedia)

Elaiosomes (Ancient Greek: ἔλαιον élaion "oil" + σόμα sóma "body") are fleshy structures that are attached to the seeds of many plant species. The elaiosome is rich in lipids and proteins, and may be variously shaped. Many plants have elaiosomes that attract ants, which take the seed to their nest and feed the elaiosome to their larvae. After the larvae have consumed the elaiosome, the ants take the seed to their waste disposal area, which is rich in nutrients from the ant frass and dead bodies, where the seeds germinate. This type of seed dispersal is termed myrmecochory from the Greek "ant" (myrmex) and "circular dance" (khoreíā). This type of symbiotic relationship appears to be mutualistic, more specifically dispersive mutualism according to Ricklefs, R.E. (2001), as the plant benefits because its seeds are dispersed to favorable germination sites, and also because it is planted (carried underground) by the ants.

Afzelia africana seeds bearing orange elaiosomes
Trillium recurvatum seeds

Elaiosomes develop in various ways either from seed tissues (chalaza, funiculus, hilum, raphe-antiraphe) or from fruit tissues (exocarp, receptacle, flower tube, perigonium, style or spicule). The various origins and developmental pathways apparently all serve the same main function, i.e. attracting ants. Because elaiosomes are present in at least 11,000, but possibly up to 23,000 species of plants, elaiosomes are a dramatic example of convergent evolution in flowering plants.

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