ArticlePDF Available

Interference of Plant Essential Oils on the Foraging Behavior of Solenopsis invicta (Hymenoptera: Formicidae)

Authors:

Abstract and Figures

Plant essential oils restrained the course of foraging behavior of individual worker ants and also influenced worker recruitment and food transport. Worker search times increased significantly among the plant oil treatments. The longest search time was observed for ants treated with essential oils of Capsicum annuum L. (Solanales: Solanaceae) and Cedrus deodara (Roxb.) G.Don (Pinales: Pinaceae). Different essential oils have significantly different effects on the recruitment of the workers, the amount of food transported, and the time spent foraging.Los aceites esenciales de plantas restringieron la dirección de la conducta individual de forrajeo de individuos de las hormigas obreras y también influyeron la selección de los trabajadores y el transporte de alimentos. El tiempo de búsqueda de los trabajadores incrementaron significativamente entre los tratamientos con aceites vegetales. Se observó que el mayor tiempo de búsqueda en las hormigas tratadas con aceites esenciales de Capsicum annuum L. (Solanales: Solanaceae) y Cedrus deodara (Roxb.) G.Don (Pinales: Pinaceae). Diferentes aceites esenciales tienen efectos significativamente diferentes en la seleción de los trabajadores, la cantidad de alimentos transportados, y el tiempo de forrajeo.
Content may be subject to copyright.
BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers,
academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research.
Interference of Plant Essential Oils on the Foraging Behavior of
Solenopsis invicta (Hymenoptera: Formicidae)
Author(s): Jie Wang, Xiaolong Qiu, Ling Zeng and Yijuan Xu
Source: Florida Entomologist, 97(2):454-460.
Published By: Florida Entomological Society
DOI: http://dx.doi.org/10.1653/024.097.0215
URL: http://www.bioone.org/doi/full/10.1653/024.097.0215
BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the
biological, ecological, and environmental sciences. BioOne provides a sustainable online
platform for over 170 journals and books published by nonprofit societies, associations,
museums, institutions, and presses.
Your use of this PDF, the BioOne Web site, and all posted and associated content
indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/
terms_of_use.
Usage of BioOne content is strictly limited to personal, educational, and non-commercial
use. Commercial inquiries or rights and permissions requests should be directed to the
individual publisher as copyright holder.
454 Florida Entomologist 97(2) June 2014
INTERFERENCE OF PLANT ESSENTIAL OILS ON THE FORAGING
BEHAVIOR OF SOLENOPSIS INVICTA (HYMENOPTERA: FORMICIDAE)
Jie Wang, Xiaolong Qiu, ling Zeng and YiJuan Xu*
Red Imported Fire Ant Research Center, South China Agricultural University, Guangzhou 510642, China
*Corresponding author’s; E-mail: xuyijuan@yahoo.com
abstract
Plant essential oils restrained the course of foraging behavior of individual worker ants
and also influenced worker recruitment and food transport. Worker search times increased
significantly among the plant oil treatments. The longest search time was observed for ants
treated with essential oils of Capsicum annuum L. (Solanales: Solanaceae) and Cedrus deo-
dara (Roxb.) G.Don (Pinales: Pinaceae). Different essential oils have significantly different
effects on the recruitment of the workers, the amount of food transported, and the time
spent foraging.
Key Words: fire ants, plant essential oil, foraging behavior, interfering, repellency ef-
fects
resumen
Los aceites esenciales de plantas restringieron la dirección de la conducta individual de
forrajeo de individuos de las hormigas obreras y también influyeron la selección de los tra-
bajadores y el transporte de alimentos. El tiempo de búsqueda de los trabajadores incre-
mentaron significativamente entre los tratamientos con aceites vegetales. Se observó que
el mayor tiempo de búsqueda en las hormigas tratadas con aceites esenciales de Capsicum
annuum L. (Solanales: Solanaceae) y Cedrus deodara (Roxb.) G.Don (Pinales: Pinaceae).
Diferentes aceites esenciales tienen efectos significativamente diferentes en la seleción de
los trabajadores, la cantidad de alimentos transportados, y el tiempo de forrajeo.
Palabras Clave: hormigas de fuego, aceite esencial de la planta, comportamiento de forrajeo,
interferir, efectos de repelencia
The red imported fire ant, Solenopsis invicta
Buren (Hymenoptera: Formicidae) causes seri-
ous damage to humans, animals and the environ-
ment. The red imported fire ant was discovered in
Southern China at the end of 2004. The ant has in-
vaded schools, rice fields, lawns, and other public
areas in both cities and rural locations (Zeng et al.
2005). Chemical treatments have been adopted as
the main method for the control of this important
medical and agricultural pest (Lofgren et al. 1975;
Adams et al. 1983; Lofgren 1986; Adams et al. 1988;
Drees & Gold 2003). However, in view of the envi-
ronmental pollution resulting from such chemicals,
the use of many types of pesticides is prohibited in
areas within the vicinity of food or water sources
(Williams & DeShazo 2004). Therefore, there is a
growing interest in treatment methods that are
non-toxic or only slightly toxic in the environment.
This interest includes fire ant repellents that can
potentially be applied in schools, nursing homes,
hospitals and other pesticide-sensitive sites. The
application of fire ant repellents to quarantined
nurseries and equipment used for working the soil
could also play an additional role in preventing
the spread of fire ants to non-infested areas (Chen
2009).
Previous reports confirmed that a number of ma-
terials and compounds were effective repellents of
fire ants (Oi & Williams 1996; Vander Meer et al.
1998; Anderson et al. 2002; Vogt et al. 2002; Chen
2005). Certain landscaping materials, such as cedar
and cypress mulch, are known to be effective repel-
lents of fire ants (Thorvilson & Rudd 2001). In addi-
tion, a recent study in Texas (USA) tested whether
a certain type of Old World bluestem grass, ‘WW-B
Dahl’ could effectively repel the red imported fire
ant (Sternberg et al. 2006). The results of that study
showed that the number of fire ant mounds were
much lower in WW-B Dahl pastures than in fields
planted with other types of grass. Furthermore,
WW-B Dahl grass proved to be an attractive alter-
native to ranchers and farmers because this grass is
favored by cattle and is very productive (Sternberg
et al. 2006). City administrators may also find this
grass helpful in keeping fire ants out of parks, land-
scaped areas, and roadsides. Anderson et al. (2002)
found that water suspensions of perilla (Salvia spp.)
leaves, pine (Pinus spp.) needles, and cedar shav-
Wang et al.: Essential Oils Affect Foraging Behavior of Solenopsis invicta 455
ings can be effective in repelling fire ants. The repel-
lency and toxicity of peppermint oil particles caused
fire ant nests to be abandoned (Appel et al. 2004).
Octanoic acid (Vander Meer et al. 1993), bifenthrin
and tefluthrin (Oi & Williams 1996) were found to
prevent potted plants from becoming contaminated
by the red imported fire ant. Chen (2005) found that
diethyl phthalate and dimethyl phthalate can be ef-
fective in repelling fire ants. Two insect-repellent
terpenoids, callicarpenal and intermedeol, isolated
from the leaves of American beautyberry (Calli-
carpa americana L.; Verbenaceae) and Japanese
beautyberry (Callicarpa japonica Thunb.) were
evaluated (using digging bioassays) and shown to
be effective as repellents against the workers of red
imported fire ants (Chen et al. 2008).
Certain components of the pepper plant Capsi-
cum annuum L. (Solanales: Solanaceae) have long
been known as insect repellents. For example, the
negative effects of extracts from the fruits and seeds
of C. annuum were observed in experiments with
the saw-toothed grain beetle, Oryzaephilus suri-
namensis (L.), (Silvanidae) and the rust-red flour
beetle, Tribolium castaneum (Herbst) (Tenebrioni-
dae), both insect pests of stored products (Iorizzi et
al. 2000). The Himalayan cedar, Cedrus deodara
(Roxb.) G.Don (Pinales: Pinaceae), is a graceful or-
namental evergreen tree that grows extensively on
the slopes of the Himalayas and shows repellent ef-
fects on the nesting of S. invicta. Cedrus deodara
could also supply repellants for use against other
pests. It has been reported that a highly effective oil
obtained from C. deodara caused complete mortal-
ity in Anopheles stephensi (Kumar & Dutta 1987).
In the above-mentioned reports, nest digging be-
havior of workers was used to evaluate the repellent
effects of plant essential oils on fire ants. However,
foraging is one of the most important daily activities
for social insects, including fire ants and other ants.
The repellent effects of plant oils on the foraging be-
havior of the red imported fire ants have not been
tested to date. In this study, the repellent effects of
several plant essential oils on the workers of the
red imported fire ant were evaluated using an ant
foraging bioassay. The results of this study identify
essential oils that significantly deter the foraging
of red imported fire ants. These findings may have
practical significance in quarantine procedures for
fire ants and for public protection.
materials and methods
Materials
Sausage (Xincheng Jinluo Meat Group Co., Ltd.,
Linyi, Shandong, China) which is made mainly
from chicken, starch and sugar was presented as
a lure to observe the foraging behavior and re-
cruitment of S. invicta. The plant essential oils of
Salvia sclarea L.; (Lamiales: Lamiacaeae), C. an-
nuum, Mentha Canadensis L.; (Lamiales: Lamia-
caeae), Mentha longifolia (L.) Huds., C. deodara,
and Pinus spp. were provided by DaMo Chemical
Co. Ltd (Tianjin, China). The essential oil product,
which in Chinese is called Feng You Jing (FYJ)
(Liang Jiefu Pharmaceutical Pte Ltd., Singapore),
was purchased from a Chinese traditional herb
medicine store in the city of Guangzhou, Guang-
dong Province, China in Oct 2010. The percentage
of each compound in FYJ reported on the label was
25% for menthol, 20% for methyl salicylate, 3% for
camphor, 3% for eucalyptus oil, 14% for eugenol
and 35% for liquid paraffin. The hexane and etha-
nol used in the bioassay were Analytical reagent
grade (Sinopharm Chemical Reagent Co. Ltd. and
DaMao Tianjin Reagent Factory).
Field Conditions
The field experiments were performed on the
campus of South China Agricultural University
in Guangzhou, Guangdong, China from Apr to
Jun 2011. The number of inseminated queens
in the polygyne colonies ranged between 2 and
27 and was determined by dissection (Porter
1992). The fire ant density at the study site was
8 mounds/100 m2. On the day of the experiments,
the weather was sunny with air temperature of
25-35 °C and 40~55% RH. The bioassays below
were conducted between 10:00 a.m. to 3:00 p.m.
Deterrent Effects of Essential Oils on the Food-
Searching Behavior of the Red Imported Fire Ant
Based on the report of Chen et al (2008) on the
bioassay of repellency against the digging behavior
of fire ant workers and on our preliminary experi-
ments, we diluted essential oils with hexane to 10-6
mL/mL for the following bioassay. First, 100 μL of
oil solution or hexane (control) was dropped onto the
center of a 70 mm-diam piece of filter paper using a
pipette. Five s later, 8 randomized filter paper piec-
es were each placed 15 cm from the nest border. A
0.5 g piece of sausage was then placed on each piece
of filter paper (Fig. 1). The search time (the time
required for one of the sausages to be discovered)
and the number of recruited workers of the fire ants
for each food source were recorded. A video camera
(Nikon D90 system) was positioned above each
mound by a tripod in order to record the numbers of
workers on the filter papers at different times. Each
treatment was repeated with 5 nests.
Interference Effects of Essential Oils on Food Transport
by Red Imported Fire Ants
Prior to the test, the sausages were cut into slic-
es weighing 0.5 g and then divided into 8 smaller
fragments each ~ 62.5 mg. A total of 100 μL of oil
solution or hexane (control) was dropped onto the
center of a piece of filter paper using a pipette. Five
456 Florida Entomologist 97(2) June 2014
s later each of the filter paper piece was randomly
placed on 1 of the 8 locations (Fig. 1) each exactly
15 cm from the nest perimeter. Eight fragments of
sausage (each approximately 0.625 mg) were then
placed on each piece of filter paper. We recorded the
time and observed and counted the number of sau-
sage fragments transported by the workers within
consecutive 5 min intervals until all of the sausage
pieces had been completely removed. Each treat-
ment was repeated with 5 nests.
Statistical Analysis
The differences in the search times, the number
of recruits and number of sausage pieces transport-
ed under the different treatments, exposure times,
and at different fire ant nests were measured. All
data were tested for normal distribution by the Sha-
piro-Wilk test and for homogeneity of variances by
Levene’s test. Two-way analysis of variance (ANO-
VA) was performed to compare the search time of
workers and the time required for food transporta-
tion exposed to different essential oils. Three-way
ANOVA was used to compare the number of fire ant
workers recruited and the amounts of food trans-
ported from different essential oil treated papers at
different exposure times and different nests. When
necessary, one way ANOVA was performed for each
single factor. All of the statistical analyses were per-
formed using the SPSS 13.0 software package.
results
Search Times with Different Essential Oils
The experiment showed that the foraging be-
havior of the fire ants was affected by the 7 types
of essential oils (Fig. 2). All of the essential oils
Fig. 1 Schematic map for placing baits on essential
oil-treated pieces of filter paper each equidistant from
the fire ant nest in the field bioassay of the repellent
effects of various essential oils. A dark circle represents
the fragment of sausage on a piece of filter paper (white
circle). The distance from the edge of each filter paper
piece to the nest was 15 cm.
Fig. 2. Time (min) required for Solenopsis invicta workers to discover a 0.5 g fragment of sausage placed on a
piece of filter paper treated with an essential oil. Each piece of filter paper was placed 15 cm from the perimeter of
the fire ant mound. FYJ is a mixture of menthol, methyl salicylate, camphor, eucalyptus oil and eugenol. Means (±
SE) followed by the same letter are not significantly different (LSD) at level of 0.05.
Wang et al.: Essential Oils Affect Foraging Behavior of Solenopsis invicta 457
except that of Mentha longifolia significantly pro-
longed the time required for the workers to arrive
at the sausage compared to the untreated control.
However only C. annuum significantly prolonged
the search time more than M. longifolia, and the
prolongation of the search time of C. annuum es-
sential oil was not significantly greater than those
of the essential oils of C. deodara, FJY, Pinus
spp., S. sclarea, or M. canadensis. In addition, we
observed that the fire ants made repeated visits
to inspect the sausage. This behavior seemed to
affect the subsequent recruitment.
The results showed that the search times of
workers for the sausage were affected significantly
by both the fire ant nest (F = 21.487, df = 4, 28; P
< 0.0001) and essential oil type (F = 10.382, df = 7,
28; P < 0.0001). Search times for the fire ants with
the C. annuum oil and C. deodara oil treatments
were 3.64 min and 2.98 min, respectively; these
values were greater than the control (1.53 min).
Recruitment of Fire Ant Workers in Different Essential
Oil Treatments
The numbers of worker ants recruited (Table
1) during the observation periods differed signifi-
cantly with different essential oils (F = 49.565, df
= 7, 280; P < 0.0001), exposure time (F = 139.701,
df = 6,280; P < 0.0001) and the fire ant nests (F =
30.540, df = 4, 280; P < 0.0001). No significant dif-
ferences in recruitment occurred during the initial
10 min of exposure time. When the exposure time
exceeded 10 min, the number of workers at the
sausage fragments differed significantly among
the different essential oil treatments. Capsicum
annuum oil had the greatest effect, followed by
the C. deodara oil, and S. sclarea oil. In the pep-
permint treatment, the number of worker ants
recruited was significantly less than the control
when the exposure time is greater than 10 min. In
the treatments of C. deodara oil and S. sclarea oil
treatments, the numbers of worker ants recruit-
ed were significantly less than in the control for
exposure times greater than 15 min and 20 min,
respectively. Worker recruitment was significantly
lower when exposure times were greater than 25
min and 35 min for the Pinus spp. oil and FYJ
treatments, respectively. These results show that
recruitment after discovery of food depend on both
the exposure time and the type of oil used. In our
test, the C. annuum oil and C. deodara oil showed
better recruitment deterrence effects on the work-
ers than the other essential oils tested (Table 1).
The Amount of Food Transported and the Time Required
for Food Transportation under Different Essential Oil
Treatments
The amount of food transported by the worker
ants (Table 2) showed an increasing trend with
table 1. the numbers of SolenopSiS invicta Workers attracted to sausage fragments on 70 mm-diam pieces of filter paper each treated With a standard
amount of an essential oil and placed 15-cm from the nest. the number of recruits Was recorded in 5 min intervals from the time of placement.
Plant oils
Number of Workers
5 min 10 min 15 min 20 min 25 min 30 min 35 min
Capsicum annuum 2.00 ± 0.87 aA 2.60 ± 1.47 aA 5.60 ± 2.48 aAB 6.80 ± 2.62 aAB 9.00 ± 4.24 aAB 10.60 ± 4.81 aB 13.00 ± 6.12 aB
FYJ 3.80 ± 2.02 aA 7.40 ± 4.14 abA 14.20 ± 4.75 abAB 20.60 ± 6.03 bcBC 28.20 ± 7.25 cdCD 33.40 ± 7.58 bcD 41.40 ± 7.97 bD
Mentha longifolia 3.40 ± 1.18 aA 9.20 ± 4.10 abA 20.40 ± 6.53 cB 30.80 ± 7.32 cC 42.00 ± 5.07 eD 51.20 ± 4.37 dE 62.00 ± 3.28 cF
Mentha canadensis 3.80 ± 0.92 aA 11.00 ± 4.18 bAB 19.40 ± 7.06 bcBC 27.80 ± 7.41 cCD 36.60 ± 8.51 deDE 45.60 ± 8.22 cdEF 56.00 ±7 .23 cF
Salvia sclarea 2.60 ± 1.47 aA 4.40 ± 2.48 abA 9.00 ± 6.24 abAB 12.60 ± 8.54 abAB 19.00 ± 8.63 abBC 29.20 ± 10.25 bCD 37.80 ± 8.10 bD
Cedrus deodara 2.20 ± 0.92 aA 4.40 ± 2.04 abA 7.20 ± 3.06 aAB 11.80 ± 3.98 abBC 13.80 ± 4.56 abBCD 16.60 ± 4.57 aCD 20.20 ± 5.46 aD
Pinus spp. 3.40 ± 1.28 aA 8.60 ± 3.15 abA 12.80 ± 5.32 abA 18.80 ± 4.26 bcB 24.20 ± 3.95 bcB 31.40 ± 2.94 bC 39.60 ± 2.77 bD
Control 3.60 ± 1.18 aA 9.60 ± 3.07 bAB 18.20 ± 4.51 bcB 28.40 ± 5.84 cC 37.80 ± 6.21 deD 45.20 ± 5.95 cdD 56.40 ± 5.82 cE
*Means in the same column followed by the same small letter or in the same row followed by the same capital letter are not significantly different (LSD) at level of 0.05.
458 Florida Entomologist 97(2) June 2014
the elapse of time (F = 5.147, df = 6, 280; P <
0.0001) and differed significantly for the same es-
sential oil treatment (F = 28.098, df = 7, 280; P <
0.0001) and the fire ant nest (F = 154.085, df = 4,
280; P < 0.0001). No significant differences were
found in the amounts of food transported for ex-
posure times of 5 min and 10 min. For exposure
times greater than 10 min, the amounts of food
transported differed significantly in the different
essential oil treatments (Table 2). Cedrus deoda-
ra oil had the greatest suppressive effect on the
amount of food transported by the workers fol-
lowed by the C. annuum oil. When the exposure
time was 10 min or less, no food transport was
found in the experiments using C. deodara oil and
C. annuum oil; however, when the time interval
was as long as 35 min, the average amount of food
transported was 4.8 and 5.4 pieces, respectively.
In contrast, the amount of food transported was 7
pieces or more for the other essential oils tested.
The time required to transport all of the food
differed (Fig. 3) markedly among the different
essential oil treatments (F = 15.257, df = 7, 28;
P < 0.0001) and the fire ant nest (F = 2.774, df
= 7,28; P = 0.046). It should be noted that all of
the treatments were presented in the same habi-
tat. The time required to transport all the food
was the greatest under the C. annuum oil treat-
ment (53.87 min), followed in declining order by
the C. deodara oil (50.23 min), the M. canadensis
oil (41.98 min), FYJ (40.57 min) and the control
(27.22 min). Thus, the C. annuum oil and the
C. deodara oil have significant impacts on the
amount of food transported and the time required
to transport all of the food.
discussion
Foraging trails of S. invicta colonies range
in length from 1 cm to 2 m (Markin et al. 1975),
which indicate the distance from the food re-
source to the tunnel opening. Therefore, we set up
the sausage only 15 cm away from the nest border
to achieve a uniform the trail length. Our field ob-
servations confirmed that the foraging trails were
almost between 5 cm to 10 cm in our experiments.
During foraging, fire ant workers detect the smell
of food with their antennae, and the type, location
and weight of the food can affect their subsequent
recruitment behavior (Xu et al. 2007). The results
of the study showed that the presence of essential
oils reduced the number of ants arriving at the
filter paper, which in turn, influenced the search
time, the recruitment and the transport of the
food by the workers.
The essential oils were clearly repellent
against the foraging of fire ants, and the type of
essential oil used made a substantial difference
in this effect. Under outdoor conditions, the C.
annuum oil and C. deodara oil were the most
effective repellents among the 7 essential oils
table 2. the numbers of sausage fragments transported bY SolenopSiS invicta Workers from 70 mm-diam pieces of filter paper each treated With a stan-
dard amount of an essential oil and placed 15-cm from the nest. the number of sausage fragments removed from each piece of filter paper
Was recorded in 5 min intervals from time of placement.
Plant oils
Sausage slices transported
5 min 10 min 15 min 20 min 25 min 30 min 35 min
Capsicum annuum 0.00 ± 0.00 aA 0.00 ± 0.00 aA 0.60 ± 0.39 aA 1.40 ± 0.63 abAB 2.80 ± 1.16 abBC 4.00 ± 1.22 abCD 5.40 ± 1.07 aD
Cedrus deodara 0.00 ± 0.00 aA 0.00 ± 0.00 aA 0.80 ± 0.59 abAB 1.00 ± 0.71 aAB 2.00 ± 1.11 aBC 3.60 ± 1.37 aCD 4.80 ± 1.16 aD
Mentha longifolia 0.60 ± 0.39 abA 2.20 ± 0.92 bB 4.60 ± 1.07 cC 6.20 ± 0.92 deD 7.40 ± 0.38 eD 9.00 ± 0.50 dE 10.00 ± 0.00 cE
Salvia sclarea 0.00 ± 0.00 aA 1.00 ± 0.5 abA 2.20 ± 0.77 abcAB 3.40 ± 1.07 abcBC 4.60 ± 1.28 bcCD 6.20 ± 1.45 bcDE 7.40 ± 1.91 abE
FYJ 0.40 ± 0.63 abA 2.00 ± 1.66 bAB 4.00 ± 2.18 cABC 5.60 ± 2.16 cdeBCD 7.00 ± 1.87 cdCD 8.50 ± 1.35 cdD 7.50 ± 0.71 abCD
Pinus spp. 0.20 ± 0.32 abA 0.80 ± 0.59 abA 2.20 ± 1.05 abcAB 3.80 ± 1.61 bcdBC 5.60 ± 1.70 cdCD 7.00 ± 1.65 cdD 7.50 ± 1.91 abD
Mentha canadensis 1.00 ± 0.71 bA 2.00 ± 1.33 bA 3.0 0± 1.41 abcAB 5.00 ± 1.11 cdeBC 7.00 ± 1.22 cdCD 8.00 ± 1.22 cdD 9.00 ± 1.58 cD
Control 0.40 ± 0.39 abA 1.20 ± 0.92 abAB 3.20 ± 1.16 bcB 6.60 ± 1.63 eC 7.25 ± 0.68 cC 9.50 ± 0.41 dD 10.00 ± 0.00 cD
*Means in the same column followed by the same small letter or in the same row followed by the same capital letter are not significantly different (LSD) at level of 0.05.
Wang et al.: Essential Oils Affect Foraging Behavior of Solenopsis invicta 459
tested. The concentration of essential oils used
in this experiment was 10-6 ml/ml, but different
concentrations may alter the effectiveness of a
repellent (Chen 2009). Future research should
consider this possibility. Our study also revealed
that the number of worker ants involved in forag-
ing activities tended to increase over time. This
may due to the gradual decrease of the repellent
effect of essential oils. It is probable that lower
repellency occurred because the outdoor air-flow
accelerated the evaporation of the essential oils.
Perhaps micro-capsules could be developed to en-
sure a greater stability of the repellent effects.
Plants use secondary metabolites to resist
potential damage by herbivores. These second-
ary metabolites are the result of the long-term
coevolution between herbivorous animals and
plants (Hartmann 2004). Compared with chemi-
cal pesticides, plant essential oils can serve as
environmentally friendly pesticides because they
are usually safer and less toxic to humans and
domestic animals, and they are more readily de-
graded in the environment (Isman 2000). Many
scientists are beginning to focus on essential oils
to develop efficient new, minimally toxic pes-
ticides for use against pests that threaten both
health and agricultural production. According to
Chen (2009), FYJ could be improved to act as a
repellent against red imported fire ants workers.
Our results indicated that the repellent proper-
ties (especially the persistence effect) of C. an-
nuum and C. deodara were stronger than that
of FYJ. Although C. annuum and C. deodara
showed effectiveness in repelling foraging work-
ers, the number of workers recruited was greater
after 30 min than 10 min. Modification of C. ann-
uum and C. deodara oils to produce longer effects
over longer periods are needed if these plant oils
are to be used as repellents for preventing food
contamination by fire ants. These oils, may also
prove useful in repelling fire ants from nesting
soil (Chen & Allen 2006).
acknoWledgments
We thank Rensen Zeng at the South China Agri-
cultural University for constructive comments regard-
ing this manuscript. The current study was supported
by the National Basic Research Program of China
(2009CB119200).
references cited
adams, c., banks, W., lofgren, c., smittle, b., and
harlan, d. 1983. Impact of the red imported fire
ant, Solenopsis invicta (Hymenoptera: Formicidae),
on the growth and yield of soybeans. J. Econ. Ento-
mol. 76(5): 1129-1132.
adams, c., banks, W., and lofgren, c. 1988. Red im-
ported fire ant (Hymenoptera: Formicidae): Correla-
tion of ant density with damage to two cultivars of
potatoes (Solanum tuberosum L.). J. Econ. Entomol.
81(3): 905-909.
Fig. 3. Effect of plant essential oils on the time (min) required by Solenopsis invicta workers to remove all 8 of
the ~ 62.5 mg fragments of sausage placed on a piece of filter paper treated with an essential oil. Each piece of filter
paper was placed 15 cm from the perimeter of the fire ant mound. FYJ is a mixture of menthol, methyl salicylate,
camphor, eucalyptus oil and eugenol. Means (± SE) followed by the same letter are not significantly different (LSD)
at level of 0.05.
460 Florida Entomologist 97(2) June 2014
anderson, J. t., thorvilson, h. g., and russell, s.
a. 2002. Landscape materials as repellents of red
imported fire ants. Southwest Entomol 27(2): 155-
164.
appel, a. g., gehret, m. J., and tanleY, m. J. 2004.
Repellency and toxicity of mint oil granules to red
imported fire ants (Hymenoptera: Formicidae). J.
Econ. Entomol. 97(2): 575-580.
chen, J. 2005. Assessment of repellency of nine phthal-
ates against red imported fire ant (Hymenoptera:
Formicidae) workers using ant digging behavior.
40(4): 368-377.
chen, J. 2009. Repellency of an over-the-counter essen-
tial oil product in China against workers of red im-
ported fire ants. J. Agric. Food Chem. 57(2): 618-622.
chen, J., and allen, m. 2006. Significance of digging
behavior to mortality of red imported fire ant work-
ers, Solenopsis invicta, in fipronil-treated sand. J.
Econ. Entomol. 99(2): 476-482.
chen, J., cantrell, c., duke, s., and allen, m. 2008.
Repellency of callicarpenal and intermedeol against
workers of imported fire ants (Hymenoptera: Formi-
cidae). J Econ. Entomol. 10(2): 265-271.
drees, b., and gold, r. 2003. Development of integrat-
ed pest management programs for the red imported
fire ant (Hymenoptera: Formicidae). J. Entomol. Sci.
38(2): 170-180.
hartmann, t. 2004. Plant-derived secondary metabo-
lites as defensive chemicals in herbivorous insects:
a case study in chemical ecology. Planta 219(1): 1-4.
ioriZZi, m., lanZotti, v., trematerra, p., and Zollo,
f. 2000. Chemical Components of Capsicum annu-
um L. var. acuminatum and their Activity on Stored
Product Insect Pests, Chapter 8, pp 77-86 In Virginia
Lanzotti and Orazio Taglialatela-Scafati [eds.], Fla-
vour and Fragrance Chemistry, Proc. Phytochem.
Soc. Europe Vol. 46, Springer, Dordrecht; London.
isman, m. b. 2000. Plant essential oils for pest and dis-
ease management. Crop Prot. 19(8-10): 603-608.
kumar, a., and dutta, g. 1987. Indigenous plant oils
as larvicidal agent against Anopheles stephensi mos-
quitoes. Current Sci. 56: 959-960.
lofgren, c., banks, W., and glanceY, b. 1975. Bi-
ology and control of imported fire ants. Annu. Rev.
Entomol. 20(1): 1-30.
lofgren, c. s. 1986. History of imported fire ants in
the United States, pp. 36-47 In C. S. Lofgren and R.
K. Vander Meer [eds.], Fire Ants and Leaf-Cutting
Ants: Biology and Management. Westview Press,
Boulder, CO. 435 pp.
oi, d. h., and Williams, d. f. 1996. Toxicity and re-
pellency of potting soil treated with bifenthrin and
tefluthrin to red imported fire ants (Hymenoptera:
Formicidae). J. Econ. Entomol 89(6): 1526-1530.
porter, s. d. 1992. Frequency and distribution of po-
lygyne fire ants (Hymenoptera: Formicidae) in Flor-
ida. Florida Entomol. 75: 248-257
sternberg, t., perrY, g., and britton, c. 2006. Grass
repellency to the red imported fire ant. Rangeland
Ecol. Mgt. 59(3): 330-333.
thorvilson, h., and rudd, b. 2001. Are landscaping
mulches repellent to red imported fire ants? South-
west Entomol. 26(3):195-204.
vander meer, r. k., seaWright, J. a., and banks, W.
a. 1993. The use of repellents for area exclusion of
pest ants, pp. 494 In K. B. Wildey and W. H. Robin-
son [eds.], Proc. 1st Intl. Conf. Insect Pests in the
Urban Environ. BPCC Wheatons Ltd. Exeter, UK.
498 pp.
vander meer, r. k., banks, W. a., and lofgren, c.
s. 2001. Repellents for ants. U.S. Patent, #6,294,577
B1.
vogt, J. t., shelton, t. g., merchant, m. e., rus-
sell, s. a., tanleY, m. J., and appel, a. g. 2002.
Efficacy of three citrus oil formulations against So-
lenopsis invicta Buren (Hymenoptera: Formicidae),
the red imported fire ant. J. Agric. Urban Entomol.
19(3): 159-171
Williams, d. f., and deshaZo, r. d. 2004. Biological
control of fire ants: an update on new techniques.
Ann. Allergy, Asthma Immunol. 93(1): 15-22.
Xu, Y. J., lu, Y. Y., Zeng, l., and liang, g. W. 2007.
Foraging behavior and recruitment of red imported
fire ant Solenopsis invicta Buren in typical habitats
of South China. Acta Ecol. Sinica 27(3): 855-860.
Zeng, l., lu, Y. Y., he, X. f., Zhang, W. Q., and liang,
g. W. 2005. Identification of red imported fire ant
Solenopsis invicta that invaded mainland China and
an infestation in Wuchuan, Guangdong. Chinese
Bull. Entomol. 42(2): 144-148.
... The repellency of many naturally occurring compounds/materials has been tested against fire ants (Table 5), including defensive compounds from other ants [57,84], plant raw materials [62,64], plant essential oils and their individual components [59,60,67,81,[85][86][87][88][90][91][92]94,98]. ...
... G.Don, Pinus spp. [90], Eucalyptus globulus Labill, Artemisia carvifolia Buch.-Ham. ex Roxb [94], Cymbopogon nardus (L.) Rendle, Cinnamomum cassia (L.) J.Pres, and Ilex purpurea Hassk [93]. ...
... ex Roxb [94], Cymbopogon nardus (L.) Rendle, Cinnamomum cassia (L.) J.Pres, and Ilex purpurea Hassk [93]. A Chinese essential oil product also show repellency against fire ants [81,89,90]. There are about 17,500 higher plant species that produce essential oils [54], but only small fraction of essential oils has been tested on fire ants, indicating that plant essential oils may be a rich source of new fire ant repellants. ...
Article
Full-text available
The invasive red imported fire ant, Solenopsis invicta Buren (hereafter, fire ants), is a significant threat to public health and a danger to livestock, pets and wildlife due to their venomous stings. The fire ant has invaded many countries and regions and has become a globally significant pest. The current major tool to manage fire ants are synthetic insecticides that are used largely as stomach poisons in bait products or contact insecticides in spray, broadcast, drench, and dust products for area and nest treatments. In addition to these insecticide products, repellants and fumigants can also be useful in some unique scenarios. The ever-increasing public concern about the potential adverse effects of synthetic insecticides on health and the environment has been a driving force for searching for safer alternatives to control fire ants. Tremendous effort has been made in developing biologically-based control for managing fire ants; however, natural products continue to be one of the most attractive sources of safe alternatives to synthetic insecticides. Here, we summarized the synthetic insecticides that are currently used in managing fire ants, available alternative products in the current market, and academic efforts in searching for fire ant natural toxins, repellants and fumigants.
... J. Presl., Artemisia annua, Eucalyptus globulus Labill. and Artemisia argyi H. Lév. and Vaniot are also reported as repellents against fire ants (Wang et al., 2012;Tang et al., 2013;Wang et al., 2014). ...
... Many plant-based products were reported as being effective against fire ants (Appel et al., 2004;Cheng et al., 2008;Wang et al., 2012;Tang et al., 2013;Li et al., 2014;Wang et al., 2014;Zhang et al., 2014;Huang et al., 2016). The present study demonstrated that sweet flag powder is also an effective plant-based product that not only kills ants, but also repels them. ...
Article
Full-text available
Due to public health and environmental issues, alternatives of synthetic pesticides have been researched for a long time. We also evaluated the toxicity and repellency of the sweet flag (Acorus calamus) powder and two bioactive compounds (α-asarone and β-asarone) against workers of the red imported fire ant (RIFA), Solenopsis invicta under laboratory conditions. Sweet flag powder applied at 1 mg/cm2 or more provided 100% ant mortality within 18 hours, and repelled almost 97% of ants within one hour. Β-asarone was the faster acting compound against RIFA compared to α-asarone and sweet flag powders. The LT50 values inclined exponentially with the increase in the application rate of the test items. On the other hand, repellency did not increase with the increase in the application rate of the test items, but did with the increase in exposure time. Based upon the results of this study, α-asarone and β-asarone, as well as sweet flag powders could be another alternative tool to control the RIFA.
... cals, phytochemicals and other bio-derived compounds have been intensively studied(Campolo et al., 2018;Geetha & Roy, 2014;Huang et al., 2019;Kimutai et al., 2017;Lee, 2018;McAllister & Adams, 2010;Mendoza-García et al., 2014Panella et al., 2005;Pinheiro et al., 2013; Regnault-Roger et al., 2012;Tawatsin et al., 2006;Wang et al., 2012Wang et al., , 2014Wiltz et al., 2007). ...
Article
The red imported fire ant (RIFA) is one of the most detrimental invasive species, threatening native ecosystems, human health and economic activities worldwide. In the quarantine zone of Taiwan, RIFA re‐infestation frequently occurs despite the intensive application of synthetic pesticides, making its control costly and ineffective. Thus, there is an urgent need to identify eco‐friendly and sustainable alternatives for controlling RIFA populations. This study examined the efficacy and feasibility of planting herbal species for RIFA control. Five herbal species, Tagetes lemmonii, Armoracia rusticana, Cymbopogon citratus, Cymbopogon nardus and Chrysopogon zizanioides, were grown in a RIFA‐infested field with local weeds as controls. Bait and pitfall traps and RIFA‐intruded plants were used to compare the ant activity in the control fields and those containing herbal plants. We further evaluated the RIFA repellent activity of the five herbal plants and their basal soil through digging bioassays. Generally, the field surveys showed more ants and intruded plants in the control than the herbal groups; however, the significance varied based on the trap type and plant species. The digging bioassays demonstrated that the aboveground parts of T. lemmonii, C. nardus, C. citratus and the belowground parts of T. lemmonii, C. citratus and C. zizanioides effectively repelled RIFA. The basal soil of T. lemmonii, C. citratus and C. nardus also exhibited deterrent activity towards RIFA. Our results demonstrated that herbal plants are eco‐friendly, sustainable alternatives for controlling and preventing RIFA infestation in severe infested and non‐infested areas.
... 12,13 Repellents have received increasing attention because a toxicologically benign repellent can exclude fire ants from certain sensitive areas where the use of synthetic insecticides is not recommended, such as hospitals, schools, and around electrical equipment. Although many compounds, particularly plant essential oils, were reported to have strong repellency against S. invicta, [14][15][16][17][18] to our best knowledge, none have been commercialized, likely due to the following reasons: (i) compounds exhibiting repellency in laboratory conditions may not prove effective in the field; (ii) some compounds may be too volatile to have reasonable long-term effects; (iii) some compounds/materials may not be cost-effective, such as some expensive plant essential oils; and (iv) the profiles and concentrations of active compounds may not be consistent in essential oils due to variations in geographic locations, seasons, strains, and age of plants, etc. 19 The essential balm, also called fengyoujing in China, is an overthe-counter medicine containing camphor, eucalyptol, methyl salicylate, menthol, and eugenol as main compounds (some brands of essential balm may also contain compounds such as phenylethanol, and accessories such as liquid paraffin and chlorophyll). 20,21 This product have been widely used in China to ease pain and relieve skin itching caused by mosquito bites. ...
Article
Full-text available
BACKGROUND An over‐the‐counter medicine product of China known as essential balm effectively repelled red imported fire ants, Solenopsis invicta Buren. However, it was not clear which chemical component(s) accounted for the repellency, and whether they would effectively repel S. invicta in the field. RESULTS Five components, eucalyptol, camphor, menthol, methyl salicylate, and eugenol, were identified in essential balm using gas chromatography‐mass spectrometry (GC‐MS). Each component elicited concentration‐dependent electroantennography (EAG) response. Under field conditions, all components showed repellency against foraging ants. Interestingly, foraging ants managed to access the food items placed on a surface smeared with eucalyptol, camphor, menthol, or methyl salicylate by depositing soil particles on the surface and then walking on soil particles. However, they failed to do so when the surface was smeared with eugenol. Repellency of eugenol lasted for > 24 h, which was much longer than that of the other four components of essential balm and is comparable to that of N, N‐diethyl‐m‐toluamide (DEET), the standard for insect repellants. CONCLUSION Olfactory response of S. invicta to all five components of the essential balm was confirmed. Each component showed repellency against S. invicta workers in the field. However, only eugenol significantly suppressed both foraging and particle‐covering behavior within 24 h. The repellent effect of eugenol lasted much longer than the other four components. Particle‐covering behavior has been largely ignored in studying fire ant repellants. Our study demonstrated that it is necessary to consider such behaviors in ant repellent bioassays in the future.
... In tests using five active components from Artemisia annua, over 80% of fire ant workers died, while cineole and D-camphor showed significant repellency (Zhang et al. 2014). Essential oils of Capsicum annuum and Cedrus deodara also strongly repelled S. invicta (Wang et al. 2014a). Kafle and Shih (2013) reported that using Syzygium aromaticum powder at 3 and 12 mg/cm 2 could kill all fire ant workers within 6 h, and repel 99% ants within 3 h. ...
Chapter
Since it was found in Taiwan and mainland, the spread of red imported fire ant Solenopsis invicta Buren into China has been continuous. In order to achieve better control of this pest, science and technology research on fire ants has advanced from many aspects. This paper presents the history of fire ant invasion and spread, estimated origins and social forms, present distribution, and potential expansion in China. Also the invasion biology and ecology is discussed in view of ecological impacts of the invasion. Management of S. invicta in China was implemented as soon as it was detected. Besides biological and physical control, monitoring, quarantine, and chemical control were widely studied and employed. Although a lot of work was done, the fire ant spread in China remains and will proceed rapidly in the future, mainly due to poor quarantine.
... Chen (2009) found that sand treated with essential balm at a concentration of 100 mg/kg completely suppressed the digging behavior of S. invicta workers. Wang et al. (2014) reported that essential balm diluted with 10 6 ml/ ml hexane decreased $27% of S. invicta foragers compared with the controls at 35 min into the experiment. Although this repellent effect was weak, it is important to note that a low concentration of essential balm was used in that study. ...
Article
Full-text available
In the present study, the repellent effects of essential balm, a traditional medicine product in China, was tested against foraging and defending red imported fire ants, Solenopsis invicta Buren, under laboratory and field conditions. The laboratory study showed that both band- (width = 1 cm) and patch-smearing of essential balm at each concentration (0.5, 1, or 2 μl/cm2) significantly decreased the number of S. invicta foragers within the 6 h observation period. Moreover, band-smearing of 2 μl/cm2 essential balm and patch-smearing of 0.5, 1 and 2 μl/cm2 essential balm inhibited most S. invicta foraging activity at 3, 6, 6, and 24 h into the experiment, respectively. The field study showed that after a disturbance was created on the S. invicta mound, there were significantly less defending ants on the substance treated (patch-smeared) with 0.5, 1, and 2 μl/cm2 essential balm than the controls, but the number of ants on the substance of these three concentrations was similar. Our study suggested that essential balm is a strong repellent against foraging and defending S. invicta and could be applied when temporary protection from S. invicta is needed.
Preprint
Full-text available
The red imported fire ant (RIFA) is one of the most detrimental invasive species, threatening native ecosystems, human health, and economic activities worldwide. In the quarantine zone of Taiwan, RIFA re-infestation frequently occurs despite the intensive application of synthetic pesticides, making its control costly and ineffective. Thus, there is an urgent need to identify effective, eco-friendly, and sustainable alternatives for controlling RIFA populations. In this study, we examined the efficacy and feasibility of planting herbal species for RIFA control. Five herbal species, Tagetes lemmonii , Armoracia rusticana , Cymbopogon citratus , Cymbopogon nardus , and Chrysopogon zizanioides, were planted in a RIFA-infested field with local weeds as controls. Bait and pitfall traps and RIFA intruded plants were used to compare the ant activity in the control fields and those containing herbal plants. The RIFA repellent activity of the five herbal plants and their basal soil was further evaluated through digging bioassays. Generally, the field surveys showed more ants and intruded plants in the control than in the herbal groups; however, the significance varied based on the trap type and plant species. The bioassays demonstrated the significant repellency of the aboveground parts of T. lemmonii , C. nardus, and C. citratus, and the belowground parts of T. lemmonii , C. citratus , and V. zizanioides against RIFA. The basal soil of T. lemmonii , C. citratus, and C. nardus also exhibited deterrent activity toward RIFA. Our results demonstrated that herbal plants are eco-friendly, sustainable alternatives for controlling and preventing RIFA infestation in severe infested and non-infested areas.
Article
Full-text available
Sweet orange oil fractions were prepared by molecular distillation of cold-pressed orange oil from sample A (Citrus sinensis (L.) 'Hamlin' from America) and sample B (Citrus sinensis Osbeck 'Newhall' from China) respectively, and their fumigant activities against medium workers of red imported fire ants (Solenopsis invicta Buren) were investigated. The volatile composition of the orange oil fractions was identified and quantified using GC-MS. Fractions from sample A (A1, A2, and A3) contained 23, 37, and 48 chemical constituents, and fractions from sample B (B1, B2, and B3) contained 18, 29, and 26 chemical constituents, respectively. Monoterpenes were the most abundant components, accounting for 73.56% to 94.86% of total orange oil fractions, among which D-limonene (65.28-80.18%), β-pinene (1.71-5.58%), 3-carene (0.41-4.01%), β-phellandrene (0.58-2.10%), and linalool (0.31-2.20%) were major constituents. Fumigant bioassay indicated that all orange oil fractions exerted good fumigant toxicity against workers of fire ants at 3, 5, 10, and 20 mg/centrifuge tubes, and B1 had the strongest insecticidal potential, followed by A1, B2, A2, B3, and A3. The fractions composed of more high volatile molecules (A1 and B1) showed greater fumigant effects than others. Compounds linalool and D-limonene, which were the constituents of the orange oil, exhibited excellent fumigant toxicity against red imported fire ant workers. Linalool killed red imported fire ant workers completely at 5, 10, and 20 mg/tube after 8 h of treatment, and D-limonene induced >86% mortality at 8 h of exposure.
Article
Full-text available
Previous studies showed that the formic acid secreted by tawny crazy ants not only has fumigation toxicity to the red imported fire ant, Solenopsis invicta Buren (Chen et al. 2013), but also can detoxify fire ant venom (LeBrun et al. 2014). These lead us to a field study to determine if low concentrations of formic acid might be useful in repelling S. invicta. Filter paper discs treated with 1.3% or 5% formic acid (v: v) or distilled water (control) were placed on each of the 46 S. invicta mounds and a disturbance was created. For a minute or less there were significantly more defending ants on the control discs than that on the paper discs treated with formic acid. After food was added and for the next 40 min, there were significantly more foraging ants on the control discs compared to the treated discs. At 50 min into the test, the number of foraging ants on the control and 1.3% formic acid treated discs was similar, but both were significantly higher than that on the 5% formic acid treated discs. In addition, the active foraging (≥ 10 ants stayed on or around the food) and burying behavior (soil particles were deposited around the food) continued to be inhibited by 5% formic acid. The potential application and ecological significant of this repellent effect is discussed.
Article
Full-text available
Experiments were conducted in Alabama, Oklahoma, and Texas to assess efficacy of raw citrus peel extract (orange oil) and a commercial citrus oil formulation for control of Solenopsis invicta Buren, the red imported fire ant. A recipe containing orange oil (equal parts orange oil, cattlemen's molasses, and compost tea at 47 mL L-' water), orange oil premixed with water to form an emulsion, and the commercial product all resulted in 80% or greater control when applied in 3.8 L of water as a mound drench. In most trials, the level of activity in mounds receiving citrus oil alternatives was statistically comparable with conventional diazinon formulations. Citrus oil alone presented mixing problems prior to application; some possible solutions are discussed. Citrus oil formulations and commercial products appear to be viable alternatives for people who do not wish to apply conventional insecti- cides against S. invieta.
Article
The historic development of integrated pest management (IPM) approaches or programs for the red imported fire ant, Solenopsis invicta Buren, are discussed. Initial attempts to eradicate this species in the U.S. failed. In the early 1980's site-specific, goal-oriented approaches were developed by adapting IPM concepts to fire ant problem areas. These programs have evolved over time and, more recently, the concept of managing fire ants on an area-wide or community-wide basis has been demonstrated. Currently, efforts are being made to investigate biological control agents to develop biologically-intensive IPM programs.
Article
Foraging behavior and recruitment of red imported fire ant Solenopsis invicta Buren were found to be dependent on habitat and food source. Detailed information about the sources of food was transferred by the first foragers to the other workers who subsequently came and collaborated in foraging. This phenomenon is known as "recruitment". The communication was complicated among the workers. S. invicta were observed in the field in typical habitats of South China, to determine how type of food and habitat affected foraging and recruitment. The foraging behaviour consisted of three steps: searching, recruitment and transportation. Searching time was different for different foods; the searching time for honey was longer than for any other food tested, The searching time was also affected by habitat, with the searching time of fire ants in a litchi orchard significantly longer than for other habitats (p <0.01). However, the mass of the food had no obvious effect on the searching time. The recruitment of fire ant workers during foraging was regular, and there was a strong relationship between the number of recruited workers and transportation time, described by the formula Na = c1e-c2T-c3e-c4T. When the food was too heavy to transport immediately into nest, the number of recruited workers was a maximum 30 min after the food was initially found. For smaller food sources maximum workers were able to be recruited sooner and the food was more rapidly transported back to the nest. For different foods, the dynamics of recruitment were similar although the number of recruits was different. The mass of the food and the habitats also affected deeply on the time spent of transportation.
Article
Anecdotal observations suggest that decorative mulches around ornamental plantings near homes and public areas may reduce activity of the red imported fire ant (Solenopsis invicta Buren) or may be repellent to colonies. Finely ground, commercially available mulches, both dry and moist, of red cedar, pine bark, red cypress, cypress, and hardwood bark were tested for repellency against laboratory and field colonies of S. invicta. Red cedar mulch showed some repellency; however, in general, small quantities of the mulches were not deterrent to S. invicta as measured by recruitment of foragers to food sources.
Article
Anecdotal evidence suggests that certain natural materials used in landscaping may repel red imported fire ants, Solenopsis invicta Buren. The repellency properties of various landscaping materials to S. invicta colonies are addressed in this study. The numbers of S. invicta on or near water-soluble extracts of materials were compared to numbers on control treatments. Sage (Saliva sp.), pine needle, and cedar shaving water suspensions were repellent to S. invicta colonies in the laboratory. Juniper extracts, DEET, neem, and naphthalene may offer short-term repellency and may contribute to integrated pest management of S. invicta in private and public outdoor areas.
Article
The foraging behavior consisted of three steps: searching, recruitment and transportation. Searching time was different for different foods; searching time for honey was longer than that for any other food tested. It was also affected by habitats with the searching time of fire ants in a litchi orchard being significantly longer than that for other habitats (p<0.01). However, the weight of the food had no obvious effect on the searching time. The recruitment of fire ant workers during foraging was regular, and there was a strong relationship between the number of recruited workers and the transportation time. When the food was too heavy to transport immediately into the nest, the number of recruited workers was maximum at 30 min after the food was initially found. For smaller sized food sources maximum recruitment of workers was possible at a shorter time and the food was more rapidly transported back to the nest. For different foods, the dynamics of recruitment were similar although the number of recruits was different. The weight of the food and the habitats also deeply affected the time spent on transportation.
Article
In order to determine the frequency and distribution of polygyne and monogyne fire ants (Solenopsis invicta) in Florida, preselected sites were surveyed from Key West to Tallahassee. Polygyne colonies were found at 15% of infested sites--a frequency similar to other states in the southeastern United States, but much less than in Texas. Polygyny was most common in the region around Marion county, but smaller populations were also scattered across the state. The density of mounds at polygyne sites was more than twice that at monogyne sites (262 versus 115 mounds/ha), although mound diameters were about 20% smaller. Polygyne and monogyne queens averaged the same size (1.42 mm, head width), but monogyne queens were much heavier (24.3 mg versus 14.4 mg) due to their physogastry. As expected, workers in polygyne colonies were considerably smaller than those in monogyne colonies (0.28 mg versus 0.19 mg, dry fat-free). /// Para determinar la frecuencia y distribución de "hormigas bravas" (Solenopsis invicta) políginas y monóginas en Florida, se muestrearon sitios preseleccionados desde Key West hasta Tallahassee. Se encontraron colonias políginas en 15% de los lugares infestados, una frecuencia similar a la de otros estados en el sureste de los EE.UU., pero mucho menor que la frecuencia de Texas. Las hormigas poliginas resultaron mas comunes en el condado Marion pero tambien se encontraron pequeñas poblaciones esparcidas a lo largo del Estado. La densidad de los túmulos en lugares con poliginia fue más del doble que en lugares con monoginia (262 versus 115, tumulos/ha), a pesar de que el diámetro medio de los túmulos fue 20% menor. Las reinas políginas y monóginas fueron del mismo tamaño (1.42 mm, ancho de cabeza) pero debido a su fisogastria, las reinas monóginas fueron mucho más pesadas (24.3 mg versus 14.4 mg). Como se esperaba, las obreras de colonias políginas fueron considerablemente menores que las de colonias monóginas (0.28 mg versus 0.19 mg, peso seco, libre de grasa).
Article
The red imported fire ant (Solenopsis invicta Buren) is an invasive pest that causes ecological disturbance and economic damage to habitats worldwide. Since its introduction to the United States 75 years ago, the ant has spread across the southeast through Texas into California and causes over $6.5 billion in damages. Conventional control techniques have not proven effective or long-lasting, leading to a search for alternative methods. We examined the ability of WW-B.Dahl Old World bluestem (Bothriochloa bladhii (Retz) S.T. Blake), increasingly used in pastures, to limit or reduce ant infestations. Pastures planted with WW-B.Dahl had about one-third the fire ant mounds found in adjacent pastures of native grass or coastal bermuda (Cynodon dactylon (L.) Pers) grass, and the difference is statistically significant (P ¼ 0.0006). No difference was found in the number of ants collected in bait cups or in mound vitality ratings, suggesting that more than one measure of ant infestation is needed to accurately assess ant populations. A reduction in fire ant mounds can improve the efficiency of haying operations and reduce wildlife impacts, suggesting broad uses for WW-B.Dahl in ant-infested areas.
Article
Red imported fire ants, Solenopsis indicts Burden, damaged 12.2-26.1% of 'Sago' and 'Russet' potatoes (Solarium tuberose L.) in small-plot field tests in 1983- 1985 and caused severe damage to commercial plantings of potatoes in the Hastings area of northeastern Florida. The extent of potato loss in both small plots and commercial fields was positively correlated with numbers of ants caught per bait trap. Average numbers of ants trapped varied from 2 to 205 per bait. The United States Standards for Grades of Potatoes define severe damage as that which results in the loss of >10% of the total weight of the potato; our data indicate severe damage occurs when the average ant catch per trap exceeds 80. This information can be useful to growers for determining when costs of ant control are economically feasible.