| |
|
|
| |
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:
|
|
| |
|
|
|
