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cDNA cloning and transcriptional regulation of the vitellogenin receptor from the imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae)Chen, Mei-Er 17 February 2005 (has links)
Receptors that transport vitellogenin into oocytes are of vital importance to egg-laying species because they promote oocyte development. In this study, we describe the cloning of the first hymenopteran vitellogenin receptor (VgR) cDNA. Using reverse transcription polymerase chain reaction (RT-PCR) and both 5- and 3- rapid amplification of cDNA ends (RACE), cDNA fragments encompassing the entire coding region of a putative VgR from fire ant (= SiVgR) were cloned and sequenced. The complete SiVgR cDNA has a length of 5764 bp encoding a 1782-residue protein with a predicted molecular mass of 201.3 kDa. The deduced amino acid sequence of the SiVgR revealed that it encoded a protein belonging to the low-density lipoprotein receptor superfamily. The number and arrangement of modular domains of SiVgR are the same as those of mosquito and fruit fly VgRs, except there are only four Class A cysteine-rich repeats in the first ligand binding domain of SiVgR compared to five in the mosquito and fruit fly. The deduced amino acid sequence of the SiVgR exhibited 35% and 31% identity to those of the mosquito and fruit fly VgRs, respectively. Northern blot analysis demonstrated that the 7.4-kb SiVgR mRNA was present only in Northern blot analysis demonstrated that the 7.4-kb SiVgR mRNA was present only in ovaries of reproductive females − both alates (virgins) and queens (mated) and was more abundant in alates. The developmental profile of transcriptional expression was determined by semiquantitative RT-PCR. It showed that the SiVgR transcript increased 6-fold from 0- to 10-days after mating, then remained constant through 30 days. It also showed that the SiVgR transcripts increased with age in alate virgin females. The transcriptional expression of the SiVgR was up-regulated more than two-fold by methoprene, a juvenile hormone analog, as determined by using an in vitro system. This suggested the SiVgR gene is JH regulated.
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Invasive interactions of Monomorium minimum (Hymenoptera: Formicidae) and Solenopsis invicta (Hymenoptera: Formicidae) infected with Thelohania solenopsae (Microsporida: Thelohaniidae)Keck, Molly Elizabeth 16 August 2006 (has links)
Thelohania solenopsae Knell, Alan, and Hazard is an internal microsporidian
that parasitizes the red imported fire ant, Solenopsis invicta Buren. This experiment
studied the invasive interactions between the native United States ant, Monomorium
minimum (Buckley), and S. invicta colonies infected with T. solenopsae and S. invicta
colonies free of parasites. This study utilized S. invicta colonies of 100, 300, 600, 800,
and 1000 workers to determine the ability of 1000 M. minimum workers to invade each
S. invicta colony size. There was a significant difference in the time for M. minimum to
invade S. invicta when comparing S. invicta colonies of 1000 workers infected with T.
solenopsae to S. invicta colonies that were uninfected. It was also determined that there
was a significant difference in the time for M. minimum to invade smaller uninfected S.
invicta colonies as opposed to larger uninfected S. invicta colonies. There was no
significant difference in the ability of M. minimum to invade smaller S. invicta colonies
infected with T. solenopsae as opposed to larger infected S. invicta colonies. It was
therefore concluded that S. invicta colonies infected with T. solenopsae were not able to
defend their colony or prevent competing ants from invading as well as uninfected S.
invicta colonies. This study also demonstrated that M. minimum is a significantly more
invasive species when compared to S. invicta, invading S. invicta territories in every
situation and doing so in a significantly shorter period of time than S. invicta colonies
invaded M. minimum colonies.
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Impact of the red imported fire ant upon cotton arthropodsDiaz Galarraga, Rodrigo Rogelio 30 September 2004 (has links)
Inclusion/exclusion field experiments demonstrated that the red imported fire ant, Solenopsis invicta Buren, did not affect the abundance of 49 groups of insects and spiders collected in pitfall traps. However, arthropod diversity was significantly greater (H' = 2.829) in exclusion plots relative to inclusion plots (H' = 2.763). Moreover, this study demonstrated that S. invicta can have an important impact upon cotton arthropod communities, including key predator species. Densities of ground beetles (Carabidae), spiders, lacewings (Chrysoperla spp.), and minute pirate bugs (Orius spp.) were significantly lower in the presence of S. invicta. However, populations of aphidophagous insects such as Hippodamia spp. and Scymnus spp. increased with cotton aphid (Aphis gossypii Glover) density early in the season. Abundance of cotton aphids was ca. 5x greater in inclusion plots, likely due to protection and tending by S. invicta. This increase was observed early in the season, though aphid populations did not reach economic levels. Predation of sentinel bollworm [Helicoverpa zea (Boddie)] and beet armyworm (Spodoptera exigua Hubner) eggs increased 20-30%, when S. invicta was present. Most predation of sentinel beet armyworm egg masses, measured via direct nocturnal observations, was due to S. invicta (68%) and cotton fleahopper [Pseudatomoscelis seriatus (Reuter)] (21%) in plots with S. invicta, and by the mite Abrolophus sp. (52%), spiders (13%) and minute pirate bug (13%) in plots without S. invicta. The frequencies of minute pirate bug, cotton fleahopper, S. invicta and native ants in beat bucket samples did not accurately reflect the frequency with which they were observed feeding on sentinel noctuid eggs. Overall, the results of these studies demonstrated that S. invicta was associated with declines in the abundances of minute pirate bug, spiders, and lacewing and with an increment in cotton aphid populations, though they did not reach the economic threshold. Moreover, S. invicta significantly increased predation of bollworm and beet armyworm eggs. All together, the results suggested that S. invicta has a net positive impact on cotton pest management.
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The potential effects of red imported fire ants (Solenopsis invicta) on arthropod abundance and Cucumber mosaic virusCooper, Laura B. January 2005 (has links) (PDF)
Thesis(M.S.)--Auburn University, 2005. / Abstract. Includes bibliographic references.
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Impact of Land Management on House Mice and Red Imported Fire AntsAbelson, Jesse R. 01 January 2011 (has links)
Understanding of mechanisms that limit the abundance and distribution of species is central to ecology. The failure of mechanisms to regulate populations can result in population outbreaks. There have been two outbreaks of house mice in the past decade in central Florida. In my study, I examine the efficacy of landscape management in the form of mowing and plowed soil barriers to limit or prevent outbreaks of house mice in a former agricultural area. House mouse populations were highly variable, but were unaffected by mowing or plowed soil barriers. Red imported fire ants were ubiquitous in the study area regardless of land management treatments. Control of fire ants did not result in more house mice on treated plots.
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The red imported fire ant, Solenopsis invicta, in early-successional coastal plain forests: tests of distribution and interaction strengthStiles, Judith H. 15 May 1998 (has links)
The red imported fire ant, Solenopsis invicta, is an abundant and aggressive component of early-successional communities in the southeastern United States. After disturbance, it rapidly invades new habitats, and once there, it has strong competitive and predatory effects on the existing arthropod community. In upland coastal plain pine forests at the Savannah River Site in South Carolina, I conducted two studies of fire ant ecology. In my first study (chapter 1), I investigated the way in which fire ants colonize early-successional road and powerline cuts through forests, and I tested whether some of these linear habitats provided better fire ant habitat than others. I found that fire ant mound density (#/ha) was similar in narrow dirt roads and in wider roads with the same intermediate level of mowing disturbance, and that density was lower in wide powerline cuts where the vegetation is only removed every five years. Furthermore, mound density was greatest near the edges of cleared roads and powerline cuts and was also greater on the northern sides of roads and powerline cuts where there was less shading from the adjacent forest. Results from this study suggest that allowing increased shading from adjacent forest vegetation, especially along northern roadside edges, would limit the suitability of road and powerline cuts as fire ant habitat, thereby slowing invasion. In my second study (chapter 2), I examined the impact of fire ants on arthropod and plant species in early-successional forest gaps. In a tritrophic system, I tested whether the top-down effect of insect herbivore consumption by fire ants was strong enough to cascade through two trophic levels and improve plant growth and fitness. I compared this potential effect to that of other arthropod predators in the community. I found that fire ants controlled the level of tissue damage to plant leaves by herbivores, but that the damage was not severe enough to influence plant growth or fitness. Fire ants had stronger negative interactions with insect herbivores than other predators in the community, and for this reason, fire ants can be considered keystone predators. This project provides further evidence that fire ants successfully invade even small patches of early-successional habitat that exist within larger matrices of uninhabitable, late-successional forest, and that once there, they have a dramatic effect on the arthropod community. Restricting the amount of early-successional habitat within southeastern forests, either as permanent road and powerline cuts or as temporary gaps, would limit the potential for strong and detrimental effects by the invasive fire ant. / Master of Science
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Implications of Relative Ant Abundance and Diversity for the Management of Solenopsis Invicta Buren with Broadcast BaitsCalixto, Alejandro Antonio 15 May 2009 (has links)
Higher densities of S. invicta in the United States relative to South America are
explained mainly by the absence of natural enemies and low interspecific competition
(IC). Despite advances in S. invicta management, broadcast insecticide baits remain as
the primary tool for effective control. I studied interspecific interactions of ants and the
use of baits on the management of S. invicta to test the following hypotheses: 1) relative
abundance of native ants increases ~25% for bait treated sites compared to untreated, 2)
behavioral dominance by S. invicta decreases ~10% in bait treated sites compared to
untreated, and, 3) foraging by S. invicta on insecticide baits is higher ~10% in low native
ant densities areas compared to high densities.
Experiments were conducted on three sites with different densities of native ants
(low, medium, high), but with similar densities of S. invicta. An enhanced BACI
(Before/After-Control/Impact) design was used. Experimental units consisted of 0.4 ha
plots. Three treatments were randomly assigned to units and replicated four times; 1)
Slow acting bait, 2) Fast acting bait, 3) Untreated Control. Samples and observations
were collected for several weeks before/after the treatments to account for temporal variation and to determine rates of reinvasion. Ants were monitored using pitfalls and
food lures. Interspecific competition was determined by applying placebo bait. Results
indicate that different management methods did not impact resident ants when they are
at low and medium densities and that S. invicta is greatly affected; at high native ant
density, competition for these baits is observed affecting both natives and S. invicta.
Reinvasion of S. invicta was reduced in areas of low and medium native ant densities
previously treated with baits and native ant abundance increased by ~25%. At high
native ant densities, reinvasion of S. invicta was similar to Control sites. I conclude: 1)
properly used, baits can help in recovery of native ant species that then compete with S.
invicta; however, rote re-treatments may have a negative impact on restored populations.
2) “bait failures” may be due to interspecific competition when initial native ant
densities are high. Preliminary management considerations and recommendations are
presented.
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Study of Midgut Bacteria in the Red Imported Fire Ant, Solenopsis invicta Büren (Hymenoptera: Formicidae)Medina, Freder 2010 May 1900 (has links)
Ants are capable of building close associations with plants, insects, fungi and bacteria. Symbionts can provide essential nutrients to their insect host, however, the development of new molecular tools has allowed the discovery of new microorganisms that manipulate insect reproduction, development and even provide defense against parasitoids and pathogens. In this study we investigated the presence of bacteria inside the Red Imported Fire Ant midgut using molecular tools and transmission electron microscopy. The midgut bacteria were also characterized by their morphology, biochemical activity, and antibiotic resistance profile.
After isolation, culture, and characterization of these bacteria, the molecular analysis revealed ten unique profiles which were identified to at least the genus level, Enterococcus sp./durans, Klebsiella ornithinolytica, Kluyvera cryocrescens, Lactococ-cus garvieae, Pseudomonas aeruginosa, Achromobacter xylosoxidans, Bacillus pumilus, Listeria innucua, Serratia marcescens, and an uncultured bacterium from the Entero-bacteriaceae. New SEM and TEM techniques revealed a possible functional association of endosymbiotic bacteria with the insect host, and it also showed the absence of bacteriocytes in the epithelial cells of the midgut. The PCR results, from the bacteria abundance and distribution studies, showed that Enterococcus sp., Kluyvera cryocres-cens and Lactococcus garvieae are the most abundant species, but they are not consistently found in all sites throughout the southeastern United States.
Kluyvera cryocrescens, Serratia marcescens, and an uncultured bacterium (isolate #38: Enterobacteriaceae) were genetically modified with the plasmid vector pZeoDsRed and successfully reintroduced into fire ant colonies. Strong fluorescence of DsRed was detected up to seven days after introduction. The transformed bacteria can still be rescued after pupal emergence; however most were passed out in the meconium. We further demonstrated that nurses contributed to the spread of the transformed bacteria within the colony by feeding the meconium to naive larvae.
Although the role of midgut bacteria in the fire ant is still unknown, we have no indication that they cause any pathology. Studies emphasizing the role of these bacteria in fire ant physiology are still ongoing. These results are the foundation for a fire ant biological control program using endosymbiotic bacteria as vectors to introduce foreign genes that express proteins with insecticidal properties.
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Red imported fire ant impact on native ants and litter removal in the post oak savannah of central TexasBedford, Theresa Louise 16 August 2006 (has links)
I examined the impacts of the invasive red imported fire ant (RIFA, Solenopsis
invicta) on native ants (Monomorium minimum, Paratrechina sp., S. krockowi, Pheidole
metallescens, Forelius pruinosus, and Camponotus americanus) and litter removal in a
post oak savannah community in central Texas. The study site was divided into 3
adjacent areas, and ant-toxic bait was used, along with additional colonies of RIFA, to
establish 3 different densities of RIFA (naturally occurring, low, and high). I surveyed
the ants in the 3 density areas and calculated the catch per unit effort for each species.
Litter baits were placed in the 3 density areas for 14 12-hour trials. The masses of the
litter removed were measured, and means were calculated for each speciesdensity/
trial/date/period/bait combination. The average amounts of litter removed by
RIFA and native ant were different in the 3 density areas (0.42 g, 0.0 g, and 0.75 g for
RIFA in the natural RIFA density area, low RIFA density area, and high RIFA density
area, respectively; 0.0 g, 0.16 g, and 0.15 g for native ants in the natural RIFA density
area, low RIFA density area, and high RIFA density area, respectively), indicating that
RIFA does have an effect on native ant habitat use.
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Utilization and evaluation of an indoxacarb-based granular bait (Advion) developed for the control of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae)Furman, Barry D. 17 September 2007 (has links)
This research evaluated the new red imported fire ant (RIFA) bait Advionâ¢.
Advion⢠contains the active ingredient indoxacarb which, following ingestion, must be
metabolized into an N-decarbomethoxyllated metabolite known as JT333 in order to
become acutely toxic. Laboratory experimentation was conducted to determine the most
effective chemical form and concentration of indoxacarb, as well as the most appropriate
grit size, for use in Advionâ¢. The results indicated that Advion⢠containing indoxacarb
was more effective than Advion⢠containing JT333, that 0.10%, 0.06%, and 0.045%
were the most effective concentrations of indoxacarb, and that standard sized grit (~2
mm) was more effective than small sized grit (<1 mm).
Field experimentation was conducted to determine the most effective concentration
and quantity of Advionâ¢, as well as the most effective placement of the bait, for
obtaining maximum control of RIFA colonies via individual mound treatments. The
results indicated that 10 g (2 Tbsp) of 0.045% Advion⢠placed around the mound in a
circle with a radius of 0.5-3.0 m was the most effective manner in which to treat
individual RIFA mounds. Field experimentation was also conducted to compare the
effectiveness of label-rate broadcast treatment with Advion⢠to the effectiveness of both label-rate broadcast treatment with Amdroî and pre-baiting broadcast treatment with
Advionâ¢. Both pre-baiting broadcast treatment and label-rate broadcast treatment with
Advion⢠ultimately resulted in 98-99% RIFA colony mortality, which was significantly
greater than the 87% colony mortality resulting from broadcast treatment with Amdroî.
The 6.2 d LT90 for label-rate broadcast treatment with Advion⢠was nearly one half that
of the LT90 for pre-baiting broadcast treatment.
Laboratory experimentation was conducted to determine whether RIFA workers were
capable of metabolizing indoxacarb into the toxic metabolite, and the results clearly
indicated that they were. Finally, field experimentation was conducted to evaluate the
effectiveness of label-rate broadcast treatment with Advion⢠at controlling multiple ant
species. The results indicated that label-rate broadcast treatment with Advion⢠resulted
in control of the RIFA and Pogonomyrmex barbatus for at least 7 wk, and Monomorium
pharaonis and Dorymyrmex pyramicus for some period of time between 3 and 7 wk.
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