Help! They're on Fire!
Help! They’re on Fire!
Among the top ten vicious
insects in the U.S. is Solenopsis, also
referred to by their common name, “Fire Ant.” Solonopsis is categorized under
the order Hymenoptera and under the family Formicidae. Solenopsis invicta (red imported fire ant) can be distinguished
from the Solenopsis geminata (tropical
fire ant) because S. geminata will
have square shaped heads that are of much greater proportion in comparison to
the rest of their body whereas S. invicta
do not have heads that are characteristically larger than the rest of their
bodies. Mounds of fire ants are usually no bigger than 18 inches in diameter
and disturbance of the mound leads to an aggressive attack from the fire ants.
The queen is capable of laying 1,500 eggs a day and after the eggs hatch, the
queen will wait to lay more eggs until the first batch matures. The larval
stage of the ant will last 6-12 days followed by the 9 day pupal stage and
concluding with the adult worker ant stage. The diet of the fire ant consists
of dead insects and dead vertebrates as well as other sources of nutrients from
the homes of humans. After a human is bitten by the ant there is typically an initial burning sensation and a
fluid filled vesicle at the site of the bite. Lastly, the site of the bite
becomes a discolored, puritic, necrotic lesion. Most venoms of fire ants are proteinaceous
mixtures, contains alkaloids, and small protein component. The venom of a fire
ant is bactericidal, hemolytic, and cytotoxic. Solenopsis invicta is native to South America but was imported into
the United States. Today, their colonies are densely dispersed around the gulf
coast and intermittently dispersed around the southern U.S. in general. Solenopsis germinata however, is commonly
located in tropics. Worker ants are polymorphic, meaning that they consists of
many sizes in the range of 2.4-6 mm whereas the queen in a single colony is
characteristically larger than the workers. The diet of fire ants typically
includes vertebrates, dead animals, insects, and often sweets and fats in human
homes.
It has been
observed that controlling the Solonopsis
invicta species is very tedious and they species has continued to climb
toward the northern region of the U.S. from their initial sight of importation
in the southern region among the gulf coast. Today, a successful biological control
has not been implemented. However, some efficacy has been found to control the
spread of Solenopsis geminata, the
tropical fire ant invading the tropics, from implementing the use of Pseudacteon bifidus, referred to as the decapitating
fly and is a natural predator to the fire ant. The decapitating fly is highly
host specific and doesn’t attack other species of ants apart from Solenopsis geminata. In addition, it is
self-sustaining and is not also attracted to feces or human food items thus
eliminating the potential for the fly to become a pest to humans.
Solonopsis invicta plays a substantial
role on the economy in the United States in regards to agriculture, human
health concern, and cost associated with controlling the ants. S. invicta
continually inhabits and causes harm to soybean crops thus dramatically
reducing the production of soybeans. In 1990, it was determined that due to S. invicta, there was a profit loss of $156
million is soybean production alone. S. invicta are also causing damage to
other essential U.S. crops, such as potato, okra, and beans, due to their
opportunistic feeding tendencies. In addition, stings of fire ants initiates a
range of possible symptoms in humans from localized swelling to anaphylactic
shock. In regards to the economic cost for the U.S. it has been found that
state governments, particularly in the south, have spent over $250 million in
order to eradicate the fire and populations.
Sanford D. Porter,
Robert M. Plowes, Charlotte E. Causton, 2018. The fire ant decapitating fly,
Pseudacteon bifidus (Diptera: Phoridae): host specificity and attraction to
potential food items.
Laura Collins and
Rudolf H. Scheffrahn, 2016. Featured Creatures: Red Imported Fire Ants
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