Fire ant predation on eggs
Predation on eggs of Pomacea canaliculata
by the fire ant Solenopsis geminata
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Fire ant predation on eggs Predation on eggs of Pomacea canaliculata |
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The ant Solenopsis geminata
The fire ant Solenopsis geminata (Fabricius, 1804) lives in large colonies.
They prefer a sunny and open habitat, eventually partly shaded. Their nests
are mostly build in drier parts of the area, although occasionally, they inhabit
wet places as well.
The colony of the fire ant consist of 3 types of ants: the queen, the soldiers
and the minor workers. The queen produces the eggs and lives deep inside the
nest. She is fed and taken care of by the workers. She is also the founder of
the colony. The large (3-5mm) and robust soldiers or major workers defend the
colony and assist the minor workers in carrying food to the nest. The major
workers are distinguished from the minor workers by their square sheped head
with strong, powerful mandibles (jaws). The minor workers, which are a bit smaller
than the major workers, do most of the daily work: they collect the food, maintain
the nest, take care of the larvea and the queen.
During warm months, new queens and male ants appear from the eggs and shortly
thereafter they leave the nest. These male and female ants posses wings and
after leaving the colony, the only thing they do is mate. The male ants die,
while the females look for a good place to start a new colony.
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Source images: Japanese Ant Color Image Database |
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The name 'fire ant'
The common name 'fire ant' is used for many species of ants of the genus Solenopsis.
This is not without reason, as their stings cause an intense, burning pain.
When the fire ant stings, she actually damages the skin and sprays an aggresive
fluid under the skin. Each ant is capable to sting several times. Immediately
after the sting has been administered, an intense pain starts and a red wheal
is formed. In the next 12-24 hours, the area swells and starts to itch. After
a week, the wheal dissapears and a smooth, pink area is left on the skin. During
the weeks thereafter, this pink spot diminishes and eventually a scar is left.
Feeding
Solenopsis geminata is not particularly selective in its feeding pattern.
These scavenging ants feed on grass seeds, arthropods, sweets, meats and whatever
they can obtain and digest. They also tend honeydew producing mealybugs, which
they protect against predators, in turn for the honeydew. This latter feeding
behaviour has a negative effect on agriculture, as the mealybugs are a pest
itself and are know to spread plant diseases.
Distribution over the world
The fire ant Solenopsis geminata is indigenous to Central America, with
its most northern distribution being the Southern regions of the USA.
Human transport of goods around the world allowed this fire ant species to become
distributed accross tropical and sub-tropical regions of various continents.
The ant became established in Africa during the first decades of the 20the century.
It was, for example, observed in Gabon in 1914. The ant became distributed to
Asia as well and was reported to occur in Thailand (1997) and the Philippines
(1998).
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Solenopsis geminata predating on Pomacea
canaliculata egg clutches.
Solenopsis geminata has been observed to eat the eggs of Pomacea canaliculata
in both the Philippines and Thailand. This is quite remarkable as almost no
other animal is known to predate on the eggs of this snail, despite their
conspicuous red colour. The eggs of Pomacea canaliculata are considered
to be unpalatable. The ants damage egg clutches and transport the eggs one by
one to their nest. Of they cannot capture the complete eggs, they destroy the
eggs capsule and collect the yolk and the embryo. Eggs of different stages of
development are attacked. The ants make no difference between fresh and hatching
clutches.
The fire ant as biological control agent
The use of biological methods to control snail populations is gaining more and
more attention. The observation of the fire ant Solenopsis geminata predating
on the eggs of the apple snail Pomacea canaliculata suggest a possible
role for this ant as a biological agent for the apple snail pest.
To achieve satisfying results in terms of snail population control with this
ant, a large number of ants should be able to enter the rice field. Therefore,
irrigation and drainage have to be adapted to allow the ants to reach the apple
snail eggs. It's also important to provide a suitable habitat for the ants to
build their nests (dry places).
Cautions should be taken as the fire ant can establish as a pest itself.
They can have a very negative impact on the local ecology, as they predate on
many species. The ants are also known to damage irrigation tubes, in which they
chew holes. Also, one should be ware of another downside of these ants: their
tendency to sting people.
It(s hard to predict if the ant Solenopsis geminata will ever be used
as biological agent to control the population of the pest snail Pomacea canaliculata
on a large scale. Taking in account the positive and negative aspects this ant
might be used in an integrated
management strategy in those areas were the ant Solenopsis geminata
is already established.
References
Acknowledgements
I wish to thank Yoichi Yusa for providing information (see article above),
his assistance, and the beautiful photograph of fire ants predating on the eggs
of Pomacea canaliculata.
'Pest Alert'
section, 'ecology' section and
'Asian
distribution map' section.
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