By: Morgan Osborn, TAMU WFSC '16
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| A red imported fire ant hill (Courtesy of Texas A&M Entomology) |
Just about everybody in the southern
United States knows the burning pain that illustrates why Solenopsis invicta is commonly known as a “fire” ant. Although their direct impact on the human
body is evident, some people may not be fully aware of their role in the
decline and disruption of many native communities and populations, including
populations of the northern bobwhite quail (Colinus
virginianus; hereafter referred to as bobwhites). Red imported fire ants
(fire ants) were introduced in the 1930s, and by the late 1980s, they already
occupied over 9.3 million square kilometers (roughly 3.6 million square miles)
of the southeastern United States (Lechner and Ribble, 1996). These fire ants are noted for their indirect
attack on bobwhites by reducing the amount of other invertebrate
food supplies and direct attacks by depredating on pipping
or hatching chicks and delivering painful stings (Guiliano et al., 1996).
Most fire ant colonies are polygamous, meaning
there are several fertile queens per colony; this allows the fire ants to
multiply at a much higher rate and spread more rapidly, thus out-competing native ants for space and resources, which is reducing their numbers by up to
90% (Morris and Steigman, 1993). The absence of natural predators, effective
competitors, and specific diseases do not control
their populations or damper their insatiable expansion (Epperson and Allen,
2010).
Current research by Silvy et al. is being conducted to further explain the
impacts on quail populations by controlling fire ant populations using
Extinguish®; this
study, when concluded, will show the impacts on bobwhite habitat, nest success,
and brood survival based on invertebrate abundance (2014). Several previous studies have shown that
overall survival can be indirectly reduced by fire ants by reduction of
invertebrates in an area and directly reduced by fire ant attacks. While there is a direct effect on pipping
chicks, the greatest threat comes indirectly.
Directly, bobwhite chicks are very susceptible to toxins introduced into
their young bodies. In studies, body
mass of bobwhite chicks decreased when exposed to the fire ant venom that is
comprised of hemolytic, cytotoxic, and necrotic properties, among other
detrimental properties (Guiliano et al., 1996).
Indirectly, bobwhites are affected by the lack of invertebrate species
to feed on. By decreasing the number of
other invertebrate species in an area, a disruption can be observed in nutrient
cycling, food webs, pollination, decomposition and seed dispersal (Epperson and
Allen, 2010).
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| A honey bee pollinating a flower (Courtesy of Texas A&M Entomology) |
As studies continue, more is
becoming known about how fire ants influence ecosystems, especially those pertaining
to bobwhite quail. An overabundance of
fire ants in an area may cause food to be a limiting
factor, and supplemental
feeding may be an ideal option to improve bobwhite
abundance. Improved cover
against avian predators, adverse conditions, and ground predators as well as supplemental
water, can
also help increase bobwhite habitat and potentially increase abundance.
Funding support provided by the Reversing the Quail Decline
Initiative and the Upland Game Bird Stamp Fund, based on a collaborative effort
by Texas Parks and Wildlife Department and the Texas A&M AgriLife Extension
Service.
Works Cited
Epperson, D. M. and
C. R.
Allen. 2010. Red Imported Fire Ant Impacts on Upland
Arthropods in Southern
Mississippi. American Midland Naturalist
163: 54-63.
Giuliano, W.
M., C. R. Allen, R.
S. Lutz and S. Demarais.
1996. Effects of Red Imported
Fire Ants on Northern Bobwhite Chicks. The Journal of Wildlife Management 60:2:
309-313.
Lechner, K.
A. and D. O. Ribble. 1996. Behavioral
Interactions between Red Imported Fire
Ants (Solenopsis invicta) and Three Rodent
Species of South Texas. The Southwestern
Naturalist 41:2: 123-128.
Morris, J.
R. and K. L. Steigman. 1993. Effects
of Polygyne Fire Ant Invasion on Native
Ants of a Blackland Prairie in Texas. The Southwestern Naturalist 38:2: 136-140.
Silvy, N.
J., J. W. Caldwell, R.
R. Lopez, B. L. Pierce,
and I. Parker. 2014. Use of Extinguish®
Plus to Control Red
Imported Fire Ants and Increase Quail Numbers.
Unpublished Data.