Myrmecochory

Most myrmecochorous plants produce seeds with elaiosomes, a term encompassing various external appendages or "food bodies" rich in lipids, amino acids, or other nutrients that are attractive to ants.

Although diaspores are seldom distributed far from the parent plant, myrmecochores also benefit from this predominantly mutualistic interaction through dispersal to favourable locations for germination, as well as escape from seed predation.

Both regions have a Mediterranean climate and largely infertile soils (characterized by low phosphorus availability), two factors that are often cited to explain the distribution of myrmecochory.

[6] Strong selective pressure or the relative ease with which elaiosomes can develop from parent tissues may explain the multiple origins of myrmecochory.

[2] Costs incurred by myrmecochorous plants include the energy required to provision diaspores, particularly when a disproportionate investment is made of growth-limiting mineral nutrients.

For instance, some Australian Acacia species invest a significant portion of their yearly phosphorus uptake in producing diaspores.

[12] The dispersal distance achieved through myrmecochory is likely to provide an advantage proportionate to the spatial scale of density-dependent effects acting on individual plants.

As such, the relatively modest distances ants transport seeds are likely to be more advantageous for myrmecochorous shrubs, forbs, and other plants of small stature.

[9] Myrmecochorous plants may benefit when ants disperse seeds to nutrient-rich or protected microsites that enhance germination and establishment of seedlings.

[14] Nest chemistry is ideally suited for seed germination given that ant colonies are typically enriched with plant nutrients such as phosphorus and nitrate.

[9] Myrmecochory is traditionally thought to be a diffuse or facultative mutualism with low specificity between myrmecochores and individual ant species.

[9][16] This assertion has been challenged in a study of Iberian myrmecochores, demonstrating the disproportionate importance of specific ant species in dispersing seeds.

Myrmecochorous plants can also cheat, either by producing diaspores with nonremovable elaiosomes or by simulating the presence of a nonexistent reward with chemical cues.

Ants are sometimes capable of discriminating between cheaters and mutualists as shown by studies demonstrating preference for the diaspores of noncheating myrmecochores.