Ant

Ant [ Biology - Ecology ]	Dictionary of botanic terminology - index of names

Ants are social insect living in organized colonies.

There are thousands of species of ants found all over the world and in just about every type of land environment. The science of studying ants is called myrmecology. The ants are one of the most successful groups of insects, they are of particular interest because they form advanced colonies. They belong to the order Hymenoptera. They always live in colonies (a colony is a group of related ants); some colonies have millions of ants in them.. Ants exhibit complex behaviour; some ants build intricate nests, some are fierce warriors, some collect and store seeds (harvester ants), some capture slaves, some live in symbiosis with plants and some farm fungi (leaf-cutter ants).
CACTI AND ANTS (an example of mutual symbiosis):
Ants	Many species of cacti (e.g. Coryphantha, Sclerocactus, Ferocactus, Tephrocactus etc.) produce nectar that feed the ants that live around their bases. This cacti are characterised by the presence of extra floral nectaries; they are glands typically located in the tubercle-grooves or in the axils (in the areole near the spine cluster) expecially around the flowers. These nectary-glands exude a viscous juice (nectar) with a high sugar-content. These glands represent a sophisticated strategy for ant attraction.	A drop of nectar on extra-floral necatary (Glandulicactus wrightii)
A reason for why cacti secrete extra floral nectar is that the presence of pugnacious ants seems to reduce the vulnerability of flower buds by herbivorous insects, resulting in greater fruit production and tissue survival. (or by decreasing seed predation on plants.) In turn, the ants are very territorial and seem to protect the plants from other insects that might try to walk up the stem and damage the fresh, delicate cells at the growing apex or steal nectar or pollen from the flowers. This strategy is useful to not only to protect the plant from small herbivores but also to promote outcrossing pollination because the only bugs that can successfully visit the flowers without being attacked by the ants are flying insects like butterflies and bees that carry pollen from other individuals and other populations, in turn increasing the genetic diversity of the species. Moreover ants can play an important rule in distributing the seeds of these Coryphanthas. (see: Myrmecochory ) A second reason is the nutrient enhancement. Ant colonies tend to concentrate nutrients in the immediate vicinity of their nests - through storing food, discarding debris, and defecating. Plants that bear extra floral nectar, attract ant nests to their base. As well the extra floral nectar might also serve to distract ants from foraging themselves at the floral nectaries, an adaptation to reduce ant visitation to flowers. See also: Myrmecophily (ant pollination) Myrmecochory (and seed dispersal)

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Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994