Fire Ant Research Articles

Agitated ants: regulation and self-organization of incipient nest excavation via collisional cues.

Ants are millimetres in scale yet collectively create metre-scale nests in diverse substrates. To discover principles by which ant collectives self-organize to excavate crowded, narrow tunnels, we studied incipient excavation in small groups of fire ants in quasi-two-dimensional arenas. Excavation rates displayed three stages: initially excavation occurred at a constant rate, followed by a rapid decay, and finally a slower decay scaling in time as t-1/2. We used a cellular automata model to understand such scaling and motivate how rate modulation emerges without global control. In the model, ants estimated their collision frequency with other ants, but otherwise did not communicate. To capture early excavation rates, we introduced the concept of 'agitation'-a tendency of individuals to avoid rest if collisions are frequent. The model reproduced the observed multi-stage excavation dynamics; analysis revealed how parameters affected features of multi-stage progression. Moreover, a scaling argument without ant-ant interactions captures tunnel growth power-law at long times. Our study demonstrates how individual ants may use local collisional cues to achieve functional global self-organization. Such contact-based decisions could be leveraged by other living and non-living collectives to perform tasks in confined and crowded environments.

Integrated mass spectrometry imaging and metabolomics reveals sublethal effects of indoxacarb on the red fire ant Solenopsis invicta.

Indoxacarb, representing an efficient insecticide, is normally made into a bait to spread the poison among red fire ants so that it can be widely applied in the prevention and control of Solenopsis invicta. However, the potential toxicity mechanism of S. invicta in response to indoxacarb remains to be explored. In this study, we integrated mass spectrometry imaging (MSI) and untargeted metabolomics methods to reveal disturbed metabolic expression levels and spatial distribution within the whole-body tissue of S. invicta treated with indoxacarb. Metabolomics results showed a significantly altered level of metabolites after indoxacarb treatment, such as carbohydrates, amino acids and pyrimidine and derivatives. Additionally, the spatial distribution and regulation of several crucial metabolites resulting from the metabolic pathway and lipids can be visualized using label-free MSI methods. Specifically, xylitol, aspartate, and uracil were distributed throughout the whole body of S. invicta, while sucrose-6'-phosphate and glycerol were mainly distributed in the abdomen of S. invicta, and thymine was distributed in the head and chest of S. invicta. Taken together, the integrated MSI and metabolomics results indicated that the toxicity mechanism of indoxacarb in S. invicta is closely associated with the disturbance in several key metabolic pathways, such as pyrimidine metabolism, aspartate metabolism, pentose and glucuronate interconversions, and inhibited energy synthesis. Collectively, these findings provide a new perspective for the understanding of toxicity assessment between targeted organisms S. invicta and pesticides. © 2023 Society of Chemical Industry.

First Report of Imported Fire Ants, Solenopsis invicta, S. richteri, and S. invicta X richteri (Hymenoptera: Formicidae) from Kentucky

Since their introduction into the United States in the early 1900's, imported fire ants, namely Solenopsis invicta Buren (Red Imported Fire Ant), S. richteri Forel (Black Imported Fire Ant), and their hybrid form Solenopsis invicta X richteri have spread throughout portions of the USA, especially in the southeastern region. Imported fire ants are a serious invasive and economically significant species in the USA and elsewhere, and their spread into new parts of the country is of great concern. Although early models predicted that the fire ants would not be able to survive very far north into the USA, these ants have nonetheless successfully continued their spread into higher latitudes. Based on Cooperative Agricultural Pest Survey (CAPS) samples, the Mississippi Entomological Museum Invasive Insect Screening Center, at Mississippi State University, has verified the presence of imported fire ants collected in Kentucky at multiple locations from 2014 to 2022.

Effects of Date of Planting on Red Ant (Dorylus orientalis) Management and Tuber Yield of Potato

An experiment was conducted to identify the appropriate time of planting for red ant management and increase the tuber yield of potato at Agriculture Research Station (ARS), Jaubari, Ilam, Nepal (2900 masl) during 2020 and 2021 planting season. Seed potatoes were planted in 9 different plant dates that were December 1, December 15, January 1, January 15, February 1, February 15, March 1, March 15 and April 1. The experiment was laid out in Completely Randomized Block Design (RCBD) with three replications. The variety used for experiment was Janakdev. The plot size for the experiment for each treatment was 4.5m2 with spacing of 75 cm x 25 cm. Data were collected on vegetative characteristics, tuber yield parameters, red ant damage scoring (1-5 scale), red ant incidence (%) in tuber and red ant infested yield (t/ha). Potatoes planted at first January produced highest tuber yield and minimum red ants infestation. Early planting delayed emergence but had maximum ground coverage. In both the years tuber was highest (19.86 t/ha and 25.48 t/ha respectively in 2020 and 2021) with seed tuber planted on January 1. Tuber yield was less both in early and late planted potatoes. Along with higher tuber yield potatoes planted on January 1 had the lowest red ant damaged score, red ant incidence (%) and less red ant infested potato tuber yield (t/ha) in both the years. It is recommended that for maximum tuber yield and minimum red ants infestation seed potatoes should be planted during first week of January in Jaubari area and similar conditions in the hills of Nepal.

Baseline Analysis of Endophytic Fungal Associates of Solenopsis invicta Buren from Mounds across Five Counties of Guangdong Province, China

Red imported fire ants mounds have been suggested as a potential reservoir for beneficial entomopathogenic fungal species that are vital for more complex roles in the ecosystem aside from infecting the insects. In the current study, the assemblage of fungal symbionts of the red imported fire ants (RIFA) were obtained across five cities in Guangdong Province, China. The sampling areas were selected because of high occurrence of fire ants mounds in the regions. Mound soils, plant debris within mounds, and ants were collected from three sampling locations in each city for potential isolation of entomopathogenic fungal associates of RIFA. All samples were collected during the spring of 2021. Following successful isolation from substrates, the patterns of fungal species composition, and richness were evaluated. In total, 843 isolates were recovered, and based on their phenotypic distinctiveness and molecular characterization based on DNA sequences of multiple loci including the ITS, SSU, and LSU regions, 46 fungal taxa were obtained, including 12 that were unidentified. Species richness and abundance was highest in the mound soils, while the lowest value was recorded from the ant body. As per the different locations, the highest abundance level was recorded in Zhuhai, where 15 fungal taxa were cultivated. The most common taxa across all substrates and locations was Talaromyces diversus. A baseline analysis of the fungal community composition of RIFA would better our understanding on the interactions between these social ants and their associated microbial organisms, and this knowledge in turn would be important for the successful management of the RIFA.

Experimental Suppression of Red Imported Fire Ants (Solenopsis invicta) Has Little Impact on the Survival of Eggs to Third Instar of Spring-Generation Monarch Butterflies (Danaus plexippus) Due to Buffering Effects of Host-Plant Arthropods

The eastern migratory population of the monarch butterfly (Danaus plexippus) has shown evidence of declines in recent years. During early spring, when the population is at its smallest, red imported fire ants (RIFA) (Solenopsis invicta) have been implicated as having devastating effects on monarch egg and larval survival, but there are no conclusive experimental data to support this contention. The purpose of this study was to determine the effect of RIFA on the survival of spring monarch eggs to third instar larvae. Three treatments were analyzed: control plots, RIFA-suppressed plots, and RIFA-enhanced plots. Other host-plant arthropods were also documented. In control plots, monarch survival was unrelated to RIFA abundance on or around the plants. For both years combined, RIFA suppression had little impact on monarch survival. In one of the two years, higher survival occurred in the suppressed treatment, but confidence in this difference was low. In control plots, monarch survival increased with increasing numbers of other arthropods (not including RIFA) on the host plant. Predator pressure did not vary relative to arthropod abundance, and RIFA only occupied plants in large numbers when large numbers of other arthropods were also present. The presence of RIFA did not affect predator pressure. RIFA artificially drawn onto host plants created artificially high predator pressure, and monarch survival was low. Long-term use of bait to control RIFA may not be cost-effective provided surrounding biodiversity is high. Efforts to promote spring monarchs should focus on promoting biodiversity in addition to planting milkweed.

Paving Behavior in Ants and Its Potential Application in Monitoring Two Urban Pest Ants, Solenopsis invicta and Tapinoma melanocephalum.

Our previous study discovered that two urban pest ants, red imported fire ants, Solenopsis invicta Buren (Formicidae: Myrmicinae), and ghost ants, Tapinoma melanocephalum (Fabricius) (Formicidae: Dolichoderinae), can pave viscose surfaces with particles to facilitate food search and transport. We hypothesize that this paving behavior can be applied to monitor S. invicta and T. melanocephalum. In the present study, 3998 adhesive tapes, each with a food source (sausage), were placed in 20 locations around Guangzhou, China (181-224 tapes per location), and their efficiency to detect S. invicta and T. melanocephalum was compared with two traditional ant-monitoring methods, baiting and pitfall trapping. Overall, S. invicta was detected by 45.6% and 46.4% of baits and adhesive tapes, respectively. In each location, the percentage of adhesive tapes detecting S. invicta and T. melanocephalum was similar when compared to baits and pitfall traps. However, significantly more non-target ant species showed up on bait and pitfall traps. Seven non-target ant species-Pheidole parva Mayr (Formicidae: Myrmicinae), Pheidole nodus Smith (Formicidae: Myrmicinae), Pheidole sinica Wu & Wang (Formicidae: Myrmicinae), Pheidole yeensis Forel (Formicidae: Myrmicinae), Carebara affinis (Jerdon) (Formicidae: Myrmicinae), Camponotus nicobarensis Mayr (Formicidae: Formicinae), and Odontoponera transversa (Smith) (Formicidae: Ponerinae)-also showed tape paving behavior, but they can be easily distinguished morphologically from S. invicta and T. melanocephalum. Our study showed that the paving behavior occurs in different subfamilies of ants (i.e., myrmicinae, dolichoderinae, formicinae, and ponerinae). In addition, paving behavior can potentially be used to develop more specific monitoring methods for S. invicta and T. melanocephalum in urban areas in southern China.

The Facet of Human Impact: Solenopsis invicta Buren, 1972 Spreading around the Atlantic Forest

The present investigation deals with some aspects of the diversity of fire ants (Hymenoptera: Formicidae) in their native range. The Red Imported Fire Ant Solenopsis invicta is native to the tropical and subtropical inland territories of South America. In Brazil, it mainly occurs around the Pantanal region and across the Paraguay river, a region composed of grasslands which are seasonally flooded. Recent studies have evidenced this fire ant species is gradually spreading to other regions of Brazil. In the present investigation, we surveyed the molecular diversity of S. invicta populations across fragments of Atlantic Forest in São Paulo, Brazil, using mtDNA COI haplotypes. Fire ant nests were sampled along the highways lining the northern and southern slope sides of the mountain range Serra do Mar, SP, Brazil. Four haplotypes were identified (H1–H4), which were assessed for similarity to deposited records by other authors, revealing that the haplotypes H1 and H2 are likely of foreign origin through recent reintroduction via a marine port to the south of the Serra do Mar mountain range. On the other hand, the haplotypes H3 and H4, predominating among the inland samples from the northern side of the mountain range, were most similar to previous records from more central regions of Brazil. Haplotypes clustered into distinct supergroups, further pointing to the occurrence of two separate expansion waves of S. invicta in the region. We suggest the obtained pattern indicates the mountain range may function as a geographical barrier deferring gene flow.

Latin American anaphylaxis registry

BackgroundRecent data about clinical features, triggers and management of anaphylaxis in Latin America is lacking. ObjectiveTo provide updated and extended data on anaphylaxis in this region. MethodAn online questionnaire was used, with 67 allergy units involved from 12 Latin-American countries and Spain. Among data recorded, demographic information, clinical features, severity, triggering agents, and treatment were received. ResultsEight hundred and seventeen anaphylactic reactions were recorded. No difference in severity, regardless of pre-existing allergy or asthma history was found. Drug induced anaphylaxis (DIA) was most frequent (40.6%), followed by food induced anaphylaxis (FIA) (32.9%) and venom induced anaphylaxis (VIA) (12%). FIA and VIA were more common in children-adolescents. Non-steroidal anti-inflammatory drugs (NSAIDs) and beta-lactam antibiotics (BLA) were the most frequent drugs involved. Milk (61.1% of FIA) and egg (15.4% of FIA) in children, and shellfish (25.5% of FIA), fresh fruits (14.2% of FIA), and fish (11.3% of FIA) in adults were the most common FIA triggers. Fire ants were the most frequent insect triggers, and they induced more severe reactions than triggers of FIA and DIA (p < 0.0001). Epinephrine was used in 43.8% of anaphylaxis episodes. After Emergency Department treatment, epinephrine was prescribed to 13% of patients. ConclusionsDrugs (NSAIDs and BLA), foods (milk and egg in children and shellfish, fruits and fish in adults) and fire ants were the most common inducers of anaphylaxis. Epinephrine was used in less than half of the episodes emphasizing the urgent need to improve dissemination and implementation of anaphylaxis guidelines.

Insecticidal Activities of Sophora flavescens Alt. towards Red Imported Fire Ants (Solenopsis invicta Buren).

The red imported fire ant (Solenopsis invicta) is a worldwide invasive and dangerous insect that is controlled mainly by chemical insecticides. Plant-derived insecticidal compounds are generally better than synthetic insecticides for environmental compatibility and the biosafety of non-targets. The toxicity of the ethanol extract of Sophora flavescens roots against S. invicta was evaluated under laboratory conditions. The ethanol extract showed toxicity against minor and medium workers of S. invicta with 7-day LC50 values of 1426.25 and 2292.60 mg/L, respectively. By bioactivity-directed chromatographic separations using the minor worker as the test insect, two active compounds, matrine and sophocarpine, were isolated from the S. flavescens total alkaloids; their chemical structure was identified by 13C NMR data. Matrine showed toxicities against minor and medium workers with 7-day LC50 values of 46.77 and 71.49 mg/L, respectively, and for sophocarpine, 50.08 and 85.87 mg/L, respectively. The two compounds could substantially reduce the foraging response, food consumption, and aggregation of S. invicta workers at a sublethal concentration of 15 mg/L. The present research suggests that S. flavescens roots have potential as a natural control agent for red imported fire ants.

Christopher T. Walsh dies at 79

Christopher T. Walsh, 79, died Jan. 10 in Boston. He was known for his research on the biosynthesis of natural products, including antibiotics; for leadership at the Massachusetts Institute of Technology and Harvard Medical School; and for foundational contributions to the field of chemical biology. Walsh’s lifelong interest in natural products began when, as an undergraduate at Harvard University, he identified the molecule responsible for fire ants’ pheromone trail ( Nature 1965, DOI: 10.1038/207320b0 ). Walsh joined the faculty at MIT in 1972 and studied reaction mechanisms in diverse cofactor-dependent enzymes. He was already chair of MIT’s Chemistry Department when he moved to Harvard Medical School in 1987 to lead the newly formed Department of Biological Chemistry and Molecular Pharmacology. While chair, he spent 3 years as president of the Dana-Farber Cancer Institute before returning to the lab full time in 1995. Walsh and colleagues identified the enzymatic mechanism for

Ant waves-Spontaneous activity waves in fire-ant columns.

Active matter, which includes crowds of organisms, is composed of constituents that independently consume and dissipate energy. Some active matter systems have been shown to sustain the propagation of various types of waves, resulting from the interplay between density and alignment. Here, we examine a type of solitary wave in dense two-dimensional columns of Solenopsis invicta, fire ants, in which the local activity, density and alignment all play a key role. We demonstrate that these waves are nonlinear and that they are composed of aligned ants that are constrained at the top by the time it takes disordered ants to activate and align and at the bottom by a density minimum enforced by gravity. Our results suggest that intrinsically switchable activity can be a productive framework to understand and trigger a broad range of wave-like behaviors, including stampedes in crowds and herds.

Sensitization of Guinea Pig Skin to Imported Fire Ant Alkaloids and Establishment of an Inflammatory Model.

Imported fire ants (IFAs), Solenopsis invicta, release their venom through multiple stings that induce inflammation, allergies, shock, and even death. Although IFA venom protein sensitization and related subcutaneous immunotherapy have been studied, few studies have examined the potential toxicity or pathogenicity of alkaloids, the main substances in IFA venom. Here, IFA alkaloids were identified and analyzed by gas chromatography-mass spectrometry; we further determined an appropriate extraction method and its effectiveness for extracting high-purity alkaloids through comparative analysis and guinea pig skin sensitivity tests. The alkaloids released from the IFA abdomen included those present in the head and thorax, and the alkaloids in the abdomen accounted for the highest proportion of the total extract. The abdominal extirpation method yielded alkaloids with a purity above 97%, and the skin irritation response score and histopathological diagnosis suggest that intradermal injection of the extracted alkaloids produced symptoms effectively simulating those of IFA stings. The successful establishment of an inflammatory model in guinea pigs stung by IFAs provides a basis for further research on the mechanism of inflammatory diseases caused by IFAs.

A β-cyclodextrin-functionalized metal–organic framework enhances the insecticidal activity of indoxacarb by affecting amino acid metabolism in red imported fire ants

The invasion area of red imported fire ants (RIFAs) in China continues to expand due to factors such as ecological changes and human activities, and the resulting damage is becoming increasingly severe. The development of smart nanopesticides that respond to environmental stimuli response with precisely controlled release has great potential in improving insecticidal effects. In this work, a smart pH and α-amylase dual stimuli-responsive pesticide delivery system was constructed by combining mono-(6-amino-6-deoxy)-β-cyclodextrin (β-CD-NH2) with zeolitic imidazole skeleton-90 (ZIF-90) nanoparticles (IDC@ZIF-90-CD) loaded with indoxacarb. The average particle size of the prepared IDC@ZIF-90-CD was 249 nm, and the loading efficiency was 18.43%. The β-CD-NH2 coating on the surface of nanoparticles reduced the photodegradation of indoxacarb and prevented the premature release of the active ingredient. In vitro release kinetics showed that IDC@ZIF-90-CD rapidly released IDC under acidic and amylase conditions, consistent with the oral and intestinal environment of RIFAs. The results of bioactivity tests showed that IDC@ZIF-90-CD enhanced the toxicity of IDC toward RIFAs by increasing feeding and damaging intestinal cells. The mortality rate of the IDC@ZIF-90-CD-treated group was significantly higher than that of the IDC EC-treated group at 72 h. The nontargeted metabolomic results showed that IDC@ZIF-90-CD affected the metabolism of RIFAs by interfering with the metabolic pathways of six amino acids and one amino acid transport carrier, whereas IDC EC interfered with only two of these amino acid metabolic pathways. Overall, this work provides insight into the effective control of RIFA damage for sustainable pest management.

Assessment of Mound Soils Bacterial Community of the Red Imported Fire Ant, Solenopsis invicta across Guangdong Province of China

Soil microbes have a wide range of distribution across the world and can be found in different agricultural and forest systems including cultivated soils, ant mounds, decaying trees, leaves, roots, and on insect bodies. Across five counties of Guangdong province of China, the assemblage of bacterial associates of red imported fire ant (RIFA) were examined. The locations were selected based on evidence of high presence of RIFA mounds in these regions. Samples were analyzed from mound soils, plant debris within mounds, and the ant body. The current study analyzed bacterial species composition and richness patterns, where 525 isolates were recovered in total, comprising 44 bacterial taxa. Taxa abundance was highest in the ant body at 35 taxa, while the values were relatively similar across soil substrate and plant debris, where 3 and 6 taxa, respectively, were recorded. The highest bacterial taxa recovery rate was recorded in Guangzhou, where a total of 17 taxa were isolated. Myroides odoratimimus was the most common across all substrates and locations among the bacterial taxa. Others with the highest isolation frequencies includes, Enterobacter cloacae, Vagococcus fluvialis, and Myroides odoratus. The understanding of the bacterial community composition of RIFA is crucial for the development of successful management techniques for these notorious social ants. In order to expand on the findings of the current study, it is imperative to understand if the associated microbial communities of the RIFA form a parasitic, antagonistic, or mutualistic relationship with their host. In this vein, further studies would examine the influence of the characterized bacterial associates of the RIFA on the social behavior, physiology, and the host response to foreign pathogens.

Gut Microbiome Composition of the Fire Ant Solenopsis invicta: an Integrated Analysis of Host Genotype and Geographical Distribution.

Gut symbiotic bacteria are known to be closely related to insect development, nutrient metabolism, and disease resistance traits, but the most important factors leading to changes in these communities have not been well clarified. To address this, we examined the associations between the gut symbiotic bacteria and the host genotype and geographical distribution of Solenopsis invicta in China, where it is invasive and has spread primarily by human-mediated dispersal. Thirty-two phyla were detected in the gut symbiotic bacteria of S. invicta. Proteobacteria were the most dominant group among the gut symbiotic bacteria. Furthermore, the Bray-Curtis dissimilarity matrices of the gut symbiotic bacteria were significantly positively correlated with the geographical distance between the host ant colonies, but this relationship was affected by the social form. The distance between monogyne colonies had a significant effect on the Bray-Curtis dissimilarity matrices of gut symbiotic bacteria, but the distance between polygyne colonies did not. Moreover, the Bray-Curtis dissimilarity matrices were positively correlated with Nei's genetic distance of the host but were not correlated with the COI-based genetic distance. This study provides a scientific basis for further understanding the ecological adaptability of red imported fire ants during invasion and dispersal. IMPORTANCE We demonstrated that gut microbiota composition and diversity varied among populations. These among-population differences were associated with host genotype and geographical distribution. Our results suggested that population-level differences in S. invicta gut microbiota may depend more on environmental factors than on host genotype.

Spread of stinging ants to oceanic islands, and the need to raise awareness of prevention and treatment of ant stings.

Venomous invasive ants are rapidly dispersing throughout oceanic islands. Medics unfamiliar with envenomation or venom-induced anaphylaxis may be unprepared for the range of possible reactions and corresponding treatments. We detail the suboptimal treatment of a patient suffering anaphylaxis from an ant sting on a remote island and describe what treatment should have been provided. The patient experienced stings on his feet from an ant later identified as tropical fire ant, Solenopsis geminata. Clinical examination revealed throat swelling without obstruction of the airway or pharynx. The patient was provided the following suboptimal treatment: intravenously-administered antihistamine and saline perfusion. Injected epinephrine should be the standard first line of treatment for anaphylaxis, even when not all symptoms are present. A rise in invasive hymenopteran stings on oceanic islands is inevitable, and proactively improving public awareness and medical training could save lives.

Toxicity and horizontal transfer of bifenthrin and dimefluthrin against the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), and the efficacy of their dust applications in the field

The red imported fire ant, Solenopsis invicta Buren, poses a significant threat to biodiversity, agriculture, and public health in its introduced ranges. While chemicals such as toxic baits and dust are the main methods for S. invicta control, toxic baits are slow, requiring approximately one or two weeks, but dust can eliminate the colony of fire ants rapidly in just three to five days. To explore more active ingredients for fire ant control using dusts, the toxicity of bifenthrin and dimefluthrin, the horizontal transfer of bifenthrin and dimefluthrin dust and their efficacy in the field were tested. The results showed that the LD50 (lethal dose) values of bifenthrin and dimefluthrin were 3.40 and 1.57 ng/ant, respectively. The KT50 (median knockdown time) and KT95 (95% knockdown time) values of a 20 μg mL–1 bifenthrin dose were 7.179 and 16.611 min, respectively. The KT50 and KT95 of a 5 μg mL–1 dimefluthrin dose were 1.538 and 2.825 min, respectively. The horizontal transfers of bifenthrin and dimefluthrin among workers were effective. The mortality of recipients (secondary mortality) and secondary recipients (tertiary mortality) were both over 80% at 48 h after 0.25, 0.50 and 1.00% bifenthrin dust treatments. The secondary mortality of recipients was over 99% at 48 h after 0.25, 0.50 and 1.00% dimefluthrin dust treatments, but the tertiary mortality was below 20%. The field trial results showed that both bifenthrin and dimefluthrin exhibited excellent fire ant control effects, and the comprehensive control effects of 1.00% bifenthrin and dimefluthrin dusts at 14 d post-treatment were 95.87 and 85.70%, respectively.

Efficacy of Various Biopesticides against Red Ant (Dorylus orientalis Westwood) in Potato Field

Red ant (Dorylus orientalis Westwood) is the most destructive insect pest of potato tubers in the field in Nepal. A field experiment was conducted at Bhatkada, Dadeldhura district, Nepal in 2020 to determine the efficacy of various biopesticides and chemical insecticide on red ants. The plot size in this experiment was 106.7 m2. Five treatments viz. Chlorpyriphos 20% EC (2 mL L-1 water), Banmaara (2 kg plot-1), Cow urine (2 L 6 L-1water plot-1), Agave (25 g tuber-1) and Control (no treatment) were evaluated in randomized complete block design with four replications. The data on plant height and the number of leaves were taken at 45, 60, and 75 days after planting (DAP). The data on slightly and severely infested tubers were taken after harvesting of potato. The results showed that Chlorpyriphos treated plots gave the lowest values of traits viz numbers of slightly infested tuber (91,500 ha-1), severely infested tubers (12,500 ha-1), weights of slight infested tubers (7,700 kg ha-1) and severely infested tuber (1,130 kg ha-1). Among the botanical pesticides, Agave treated plots provided the second lowest values of numbers of slightly infested tuber (145,500 ha-1), severely infested tubers (37,400 ha-1), weights of slight infested tubers (13,400 kg ha-1) and severely infested tuber (3,110 kg ha-1). The results showed that the Agave treatment provided the highest marketable yield (50,900 kg ha-1). Thus, Chlorpyriphos and Agave could be used to efficiently protect potato tubers from red ant in potato field.

Survival of eggs to third instar of late-summer and fall-breeding monarch butterflies (Danaus plexippus) and queen butterflies (Danaus gilippus) in north Texas

IntroductionEastern migratory monarch butterflies (Danaus plexippus) have declined over 80% in recent years, but little is known about fall reproduction in the southern U.S. where monarchs may compete with queen butterflies (Danaus gilippus).Aims/methodsWe provide data on the survival to third instar, associated arthropods, and phenology of fall breeding monarchs and queens in Texas.ResultsMonarch and queen survival was relatively high, but varied among years. Oleander aphids (Aphis nerii), spiders, and red imported fire ants (Solenopsis invicta) had minor negative effects on survival. The abundance of monarchs and queens on the study site peaked three to four weeks before the main passage of monarchs in the area. Queens had similar phenology and exhibited a migratory pattern similar to monarchs but on a smaller scale.DiscussionSurvival of fall monarchs is relatively high and potentially important for winter roost recruitment. Fall survival was not greatly affected by any particular arthropod taxon, but may be affected by precipitation. Fall reproduction is a response to available host plants and its timing enables pupae to eclose in time for migration to winter roosts.Implications for insect conservationManagement of Asclepias viridis and other native milkweeds to facilitate fall reproduction could facilitate recovery of monarchs if it buffers variable productivity further north. Management should use mowing and burn schedules that promote high quality host plants. Populations of queens should be monitored for their potential to compete with monarchs especially in response to the potential impacts of parasite resistance and climate change.