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Diaspore of Carex oxyandra . a. Utricle with elaiosome. The lower smooth part indicated by a bracket is the elaiosome. b. Diaspore whose elaiosome was partially bitten off by Lasius japonicus . Arrow indicates an eaten part of diaspore. Bar = 1 mm.
Source publication
Seed dispersal by ants, myrmecochory, is reported for the first time for Carex oxyandra (Franch. & Sav.) Kudo var. oxyandra (Cyperaceae) from Japan. We found utricles of C. oxyandra with elaiosomes and the removal of diaspores (achenes enclosed by urticles) by the ant, Lasius japonicus Santschi (Formicinae) in grassland. In the laboratories L. japo...
Citations
... In Australia, Lepidosperma is the primary sedge genus thought to be myrmecochorous, although myrmecochory in other genera of Cyperaceae is known elsewhere, e.g. Carex (Handel 1976;Kjellsson 1985Kjellsson , 1991Tanaka et al. 2015) and Scleria (Gaddy 1986) in the northern hemisphere, and Ficinia in South Africa (Slingsby and Bond 1981;Bond and Slingsby 1983). As the majority of myrmecochores in Australia are woody perennials (Berg 1975;Thomson et al. 2010), a myrmecochorous sedge is anomalous. ...
The diaspores of Lepidosperma Labill. (Cyperaceae) have thickened perianth members persistent at the base of the fruit, which are generally assumed to form a unique type of elaiosome but this assumption has not been tested rigorously. We tested whether the perianth provides a lipid-rich food reward and improves diaspore removal by ants in three species of Lepidosperma. We measured (i) the lipid and fatty acid composition of the fruit and perianth of two species of Lepidosperma, and of the seed and aril of two species of Acacia (known myrmecochores), (ii) the relative attractiveness to ants of the perianth in three species of Lepidosperma, and (iii) the relative attractiveness to ants of the diaspores of the same species of Lepidosperma compared with the two species of Acacia. We found that (i) Lepidosperma diaspores show traits consistent with myrmecochory, particularly the high lipid content (∼12–60%) and fatty acid profile of perianth material, (ii) isolated perianth members were removed in greater numbers over all times than were diaspores only (i.e. with perianth removed) in two species of Lepidosperma (n = 100, P = 0.035 and 0.047), whereas the difference was equivocal in the third species (n = 100, P > 0.05), and (iii) Lepidosperma and Acacia diaspores were removed in similar numbers over time (n = 100, P > 0.5). Seven species of diaspore-removing ant were observed, with Rhytidoponera metallica accounting for ∼50% of observed removals. We conclude that the perianth members of Lepidosperma are an elaiosome that provides a lipid-rich food reward.
... To identify seeds and other diaspores with nutritive tissues attractive to ants (henceforth 'seeds') in the Patagonian steppe, we conducted a bibliographical survey of flora catalogues (Zuloaga et al., 2009; Sistema de Información de Biodiversidad, 2019), field guides (Green & Ferreyra, 2012), compendiums (Correa, 1969(Correa, -1998, and research publications (Handel, 1978;Pemberton & Irving, 1990;Mayer et al., 2005;Rico-Gray & Oliveira, 2007;Lengyel et al., 2010;Tanaka et al., 2015). In addition, we consulted local experts, revised plant collections, and compiled field observations. ...
1. Seed dispersal by ants, i.e. myrmecochory, is important in drylands because ants may contribute to overcoming the typical resource limitation imposed on plants in these environments. Dispersal distance and directed dispersal of seeds to nutrient‐enriched ant nests benefit plants by reducing parent or sibling competition and improving growth, survival, and reproduction.
2. This study investigated the role of ants as seed dispersers in the semi‐arid Patagonian steppe. In particular, this study surveyed native and exotic plants potentially dispersed by ants (i.e. those with nutritive tissues attached to seeds that could attract ants), identified seed disperser ants, and compared their effectiveness as dispersers (i.e. number of removed seeds, transport distance, and seed fate).
3. It was found that 9% of plant species could be potentially dispersed by ants, and field experiments were carried out with five of them (three natives and two exotics). Six ant species dispersed seeds, with Dorymyrmex tener being the most effective seed disperser, interacting preferably with an exotic seed. Finally, the types of nutritive tissues of the seeds are important in determining the attractiveness towards different ant foraging groups.
4. This study's results highlight that ant foraging group and seed's nutritive tissues are relevant traits that could help in understanding ant–seed interactions. Furthermore, in the Patagonian steppe, there are effective seed disperser ants that could play an important role in the distribution of native plants, as well as the spread of invasive species, being especially relevant in nutrient‐poor drylands due to the benefits provided by myrmecochory.
... However, the sedge is able to expand only incrementally outward merely by clonal growth. From the other viewpoint of seed dispersal, it has been reported that Carex oxyandra seeds are dispersed by ants: an elaiosome is attached to the seed surface, and ants take the seeds to their nest and bite off only the elaiosome [9]. Consequently, we suggest a process for colonizing by Carex oxyandra in Fig. 5. How long the dominance of the sedge lasts or whether dwarf bamboo can recover in the sedge-dominated community are worth investigating in terms of the regeneration of the forest. ...
Many old trees were blown down by typhoons in 1959 and 1961 in a natural coniferous forest deep in the mountains of Kiso District, Central Japan, and dense dwarf bamboo subsequently delayed the growth of tree seedlings. Forest engineers have tried to suppress dwarf bamboo to promote the regeneration of arboreal vegetation. However, after suppression of dwarf bamboo, an unknown grass unexpectedly colonized the area and replaced them. Afterward, almost no tree seedlings could be observed in the newly formed community, which seemed to worsen the extent of regeneration. It has been identified that the grass as Carex oxyandra, a native sedge species indigenous to Kiso District. Commonly, Carex oxyandra grows as short as about 10 cm like lawn grass, but it seems to have exceedingly enlarged the size in the community. Thus, investigation on the morphological variation of this sedge in Miure Experimental Forest within the Kiso National Forest was carried out. Leaf blade length, basal tiller length, and number of leaves per tiller were measured in upper and lower stands on three slopes in 2009. Results revealed that leaf blade length and basal tiller length in lower stands were approximately twice as large as those in upper stands on each slope, whereas the number of leaves per tiller was almost the same (8.8-9.4 leaves). Consequently, tussocks of this sedge became large in lower stands on a slope, which made the community overcrowded and damp, restricting tree regeneration.
