Bioactivities of scent gland chemicals from Mictis fuscipes Hsiao (Hemiptera: Coreidae) on Solenopsis invicta Buren (Hymenoptera: Formicidae).

BACKGROUND: Given the chemical diversity within stink bugs scent glands, they can be convenient models for bioprospecting novel pest control products. Preliminary behaviour observations indicated that adult Mictis fuscipes stink bugs secrete liquid droplets when defending against Solenopsis invicta fire ants, killing them within minutes. Hence, this study aimed to analyse the chemical composition of the metathoracic scent gland secretions of M. fuscipes adults, as well as assess their biological activities against fire ants. RESULTS: Bioassaying fire ants against secretions of several local stink bugs confirmed that the defensive secretions of two Mictis species are significantly more lethal, where M. fuscipes was the most lethal. Volatiles chromatography analysis indicated the secretions of female and male M. fuscipes stink bugs contains 20 and 26 components, respectively, chiefly hexanoic acid and hexyl hexanoate. Five compounds were consistently present in the secretion of female adults: hexyl hexanoate, hexanoic acid, hexyl acetate, hexyl butyrate, and eugenol. These yielded a strong electrophysiological antennal (EAD) response from S. invicta workers, female alates and males, where hexyl acetate showed the strongest response. The combination of these five compounds proved strongly repellent to S. invicta. When tested singly, hexanoic acid, hexyl butyrate, hexyl hexanoate, and eugenol were repellent to S. invicta, but hexyl acetate seemed slightly attractive. Additionally, the same mixture of five components exhibited strong contact and fumigant toxicity towards S. invicta workers, eugenol being the strongest. CONCLUSION: Defensive chemicals of M. fuscipes exhibit robust biological activity against S. invicta and could inspire the development of biopesticides. © 2024 Society of Chemical Industry.

Hitting the Road: Haplotype Diversity of Fire Ants Nesting on Disturbed Atlantic Forest Habitats.

Ants of the genus Solenopsis are globally distributed, presenting high diversity and many generalist species. In South America, the dominant species is Solenopsis saevissima (Smith, 1855), commonly found nesting in grassy fields surrounding humanized areas. In spite of being so common, there has been no research evaluating the effect of human disturbances on the mitochondrial DNA (mtDNA) haplotype diversity in this species. In this context, we here characterized the mtDNA haplotype diversity in S. saevissima nests by highway roadsides, dust roads, and forest borders of Atlantic Forest, based on partial sequences of cytochrome c oxidase subunit I (COI). Based on the facts that the species is a rapid colonizer of disturbed habitats, we specifically probed how the genetic diversity of native S. saevissima is impacted by highways and roads infrastructure expanding around the rainforest. Species diagnosis was established both by morphological characters and obtained mtDNA COI sequences. Overall, the species exhibited high haplotypes and nucleotide diversity, particularly around forest borders; though all haplotypes seemed closely related across the different habitats. We identified seven mitochondrial haplotypes (H1 to H7), where haplotype H1 was exclusively found in highway roadside nests, and H7 on dust roads; the remaining haplotypes were recorded from all habitats. Haplotype H1 was geographically isolated to the south of the Atlantic Forest, supporting previous suggestions that it acts as a biogeographical barrier. The pattern is suggestive of a recent species expansion, probably resulting from extensive habitat fragmentation. Taken together, our data demonstrates fire ant haplotypes prevailing in some anthropized habitats, characterizing how a native species lining the remnants of the Brazilian Atlantic Forest might be a concern for environmental conservation.

First record of Fusarium concentricum (Hypocreales: Hypocreaceae) isolated from the moth Polychrosis cunninhamiacola (Lepidoptera: Tortricidae) as an entomopathogenic fungus.

Fusarium concentricum Nirenberg & O' Donnell (Ascomycota: Hypocreales) is a fungal species known to infect plants, but never reported as entomopathogenic. Polychrosis cunninhamiacola Liu et Pei (Lepidoptera: Tortricidae: Olethreutinae) is a major and widespread insect pest causing economic losses to cultivated Chinese fir Cunninghamia lanceolata (Lamb.) Hook. It is routinely controlled by extensive use of chemical insecticides, which is perceived as environmentally unsustainable. During March and April of 2019-2020, muscardine cadavers of larvae and pupae of P. cunninhamiacola infected with growing fungus were collected in a fir forest in northern Guangdong Province, China. Conidia were isolated and cultured on PDA medium, from which the fungal strain was identified as F. concentricum FCPC-L01 by morphology and by sequence alignment match with Tef-1α gene. Pathogenicity bioassays at the conidial concentration 1 × 107 revealed P. cunninhamiacola adults and Danaus chrysippus (L.) (Lepidoptera: Nymphalidae) larvae are sensitive to the fungal infection, but not the fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae). We believe results indicate this fungal strain might be applicable against specific target insect pests. As this is the first record of a natural infection caused by F. concentricum in insects, we propose host specificity tests should be done to evaluate its potential as a biocontrol agent.

Implementation of caregiver depression screening in an urban, community-based asthma clinic: a quality improvement project.

OBJECTIVE: Caregiver depressive symptoms are prevalent among children with asthma and associated with greater asthma morbidity. Identifying caregivers with depression and connecting them to appropriate treatment may reduce child asthma morbidity. The goal of this project was to implement a workflow for caregiver depression screening and treatment referral in an urban, community-based, asthma clinic serving under-resourced children. METHODS: The Model for Improvement with weekly Plan-Do-Study-Act cycles was utilized. A two-item depression screening tool (Patient Health Questionnaire-2; PHQ-2) and an acceptability question using a 5-point Likert scale were added to an existing social needs screening checklist administered to all caregivers during the child's clinic visit. Caregivers with a positive PHQ-2 score (≥3) received the PHQ-9. Positive screens on the PHQ-9 (≥5) received information and referrals by level of risk. PHQ-9 positive caregivers received a follow-up phone call two weeks post-visit to assess connection to support, improvement in depressive symptoms, and satisfaction with resources provided. RESULTS: The PHQ-2 was completed by 84.4% of caregivers (233/276). Caregivers had a mean age of 33.8 years (SD = 8.3; Range: 18-68) and were predominately female (86.4%), Black (80.4%), and non-Hispanic (78.4%). The majority (72.3%) found the screening acceptable (agree/strongly agree). Nearly one in six caregivers (37/233, 15.9%) reported depressive symptoms (PHQ-2 ≥ 3); 11.6% (27/233) had clinically significant symptoms (PHQ-9 score ≥ 10); and 2.1% (5/233) reported suicidal thoughts. Of those with depressive symptoms, 70.3% (26/37) participated in the follow-up phone call. While 50% (13/26) reported the resources given in clinic were "extremely helpful," no caregivers contacted or used them. CONCLUSIONS: Caregiver depression screening was successfully integrated into a pediatric asthma clinic serving under-resourced children. While caregivers found screening to be acceptable, it did not facilitate short-term connection to treatment among those with depressive symptoms.

Physiological Variables Influenced by 'Candidatus Liberibacter asiaticus' Infection in Two Citrus Species.

'Candidatus Liberibacter asiaticus' is the bacterium associated with the citrus disease known as huanglongbing (HLB). This study evaluated the influence of 'Ca. L. asiaticus' infection on a number of key plant physiological variables concerning photosynthesis, cell integrity, reactive oxygen species scavengers' activity, and osmoregulation of two different species of citrus-the pomelo Citrus maxima and the mandarin C. reticulata 'Tankan'-relative to their measured 'Ca. L. asiaticus' infection load. Results indicated that all measured physiological variables except soluble sugar were affected by increased 'Ca. L. asiaticus' infection titers, wherein the variety C. maxima proved overall more resistant than C. reticulata. 'Ca. L. asiaticus' infection was linked in both plants to decrease in chlorophyll concentration, cell membrane permeability, and malondialdehyde, as well as increased free proline and starch contents. Chlorophyll fluorescence measurements taken 9 months after grafting the mandarin C. reticulata with 'Ca. L. asiaticus' scions revealed a significant decrease in the photosynthesis variables maximum photochemical quantum yield of photosystem II (PSII), effective photochemical quantum yield of PSII, and coefficient of photochemical fluorescence quenching assuming interconnected PSII antennae, whereas nonphotochemical fluorescence quenching increased significantly; C. maxima plants, on the other hand, did not show significant differences until the 12th month from infection exposure. The variables superoxide dismutase, catalase, peroxidase, and soluble protein initially increased and later decreased. In addition, progression of 'Ca. L. asiaticus' replication in both citrus species was accompanied by rapid changes in three reactive oxygen species scavenging enzymes in C. maxima, while the pattern was different in C. reticulata. We hypothesize that the observed interspecific differences in physiological change are related to their relative resistance against 'Ca. L. asiaticus' infection. These results provide a scaffold for better describing the pathogenesis, selecting the most resistant breeds, or even validating pertaining omics research; ultimately, these detailed observations can facilitate the diagnosis of 'Ca. L. asiaticus' infection.

On the Biological Diversity of Ant Alkaloids.

Ants have outstanding capacity to mediate inter- and intraspecific interactions by producing structurally diverse metabolites from numerous secretory glands. Since Murray Blum's pioneering studies dating from the 1950s, there has been a growing interest in arthropod toxins as natural products. Over a dozen different alkaloid classes have been reported from approximately 40 ant genera in five subfamilies, with peak diversity within the Myrmicinae tribe Solenopsidini. Most ant alkaloids function as venom, but some derive from other glands with alternative functions. They are used in defense (e.g., alarm, repellants) or offense (e.g., toxins) but also serve as antimicrobials and pheromones. We provide an overview of ant alkaloid diversity and function with an evolutionary perspective. We conclude that more directed integrative research is needed. We suggest that comparative phylogenetics will illuminate compound diversification, while molecular approaches will elucidate genetic origins. Biological context, informed by natural history, remains critical not only for research about focal species, but also to guide applied research.

Home direct-to-consumer telehealth solutions for children with mental health disorders and the impact of Covid-19.

Delivery of mental health treatment in the home can close gaps in care. Telehealth also provides access to healthcare that has been disrupted due to the COVID-19 pandemic. In 2016, a home direct-to-consumer telehealth program was initiated. Mental health encounters made up a significant portion of all telehealth encounters and COVID-19 had a significant impact on accelerating the utilization of telehealth. Telemental health has been more successful at meeting targeted volumes than the overall health system. Of all the mental health diagnoses before and during COVID-19, attention deficit hyperactivity disorder, Autism Spectrum Disorder, and Anxiety Disorder were most common. The direct-to-consumer telehealth program saved patients a significant amount of travel miles and associated time, based on data from the period before COVID-19. Payment reimbursement for direct-to-consumer telehealth professional services was similar to reimbursement for in-person visits. This program demonstrates direct-to-consumer telehealth is a feasible and acceptable care modality for a variety of youth mental health disorders.

Preliminary Report on the Acquisition, Persistence, and Potential Transmission of Citrus tristeza virus by Diaphorina citri.

Citrus tristeza virus (CTV) is one of the most important citrus tree viruses: a graft-transmissible virus that can be vectored by several aphid species. Diaphorina citri is the insect vector of "Candidatus Liberibacter spp.", a bacterium associated with citrus Huanglongbing (HLB). However, no detailed description of the relationship between CTV and D. citri has been reported. In this study, D. citri adults collected from CTV-infected "Shatangju" mandarin, "Newhall" sweet orange, and "fingered citron" trees in different orchards yielded CTV-positive rates of 40%, 65%, and 95%, respectively, upon detection by conventional PCR. Illumina HiSeq sequencing followed by de novo assembly recovered the primary full CTV genome from the RNA of 30 D. citri adults sampled from CTV-positive citrus plants. Molting and adult emergence did not affect the presence or titers of CTV within the D. citri; however, the persistence of CTV in psyllids varied among different host plant species. Groups of 10 D. citri (from a population 85% CTV-positive) were shown to potentially transmit CTV to two citrus species, "Shatangju" mandarin and "Eureka" lemon, yielding 58.33% and 83.33% CTV-positive plants, respectively. No transmission of CTV to orange jasmine plants occurred. Thus, this study reports on the ability of D. citri to acquire and transmit CTV, making D. citri as a vector of two important citrus pathogens, warranting further attention and investigation.

Metarhizium Entomopathogenic Fungi Against the Beetle Brontispa longissima (Coleoptera: Hispidae): Isolation and Species Identification.

Seven entomopathogenic fungi strains (M1-7) were isolated from field-obtained dead coconut hispine beetles Brontispa longissima (Gestro), identified to species, and bioassayed for their pathogenicity. According to ITS sequences, all isolates belong in the genus Metarhizium, mainly M. flavoviride and M. anisopliae. Measured median lethal times (LT50) of 1×107 conidia/ml of M1-7 against fourth-instar B. longissima larvae within 15 d following exposure were, respectively: 5.43, 10.64, 11.26, 10.93, 6.62, 4.73, and 5.95 d. The isolate M6 yielded the highest mortality to fourth-instar larvae, and was thus selected to be tested against other larval instars and adults of B. longissima, after Time-Dose-Mortality (TDM) models. M6 proved more pathogenic against larvae than adults. The obtained bioassays data produced a good fit to the TDM models, yielding estimated LC50 and LT50 for each of the tested developmental stages of B. longissima. Both the obtained dose (ß) and time effect (ri) parameters from TDM models suggest that first-instar larvae are the most susceptible life stage of the pest insect, while adults are more resistant to M6 infection. Calculated LC50 values were, respectively, 1.23×103 and 1.15×106 conidia/ml for first-instar larvae and adults, on the 15th day following M6 inoculation. Estimated LT50 were 3.3 and 5.9 d for first-instar larvae and adults, respectively, at 1×108 conidia/ml. Taken together, these results would suggest Metarhizium M6 as an option for the biological control of B. longissima in the field.

Differential Behavioral Responses of Solenopsis invicta (Hymenoptera: Formicidae) Workers Toward Nestmate and Non-Nestmate Corpses.

The removal of corpses (aka 'necrophoric behavior') is critical to sanitation in ant colonies. However, little is known about differences in the necrophoric responses of Solenopsis invicta workers towards corpses of nestmates and non-nestmates. We introduced corpses of S. invicta workers from either intracolony (i.e., nestmate) or intercolony (i.e., non-nestmate) origin at the entrance of artificial nests, and recorded workers' aggressive responses and necrophoric behaviors for analysis. Solenopsis invicta workers displayed distinct responses towards corpses of different origins. Specifically, resident workers were more likely to remove fresh non-nestmate corpses than nestmate corpses, but there was no difference regarding corpses that had been dead for 15 min or longer. Resident workers reacted more aggressively to, and removed more quickly, fresh non-nestmate corpses than corpses of their nestmates. On the other hand, there was no significant difference in the removal time between nestmate and non-nestmate corpses that had been dead for 15 min or longer. Resident workers always displayed stronger aggressiveness towards non-nestmate corpses than nestmate corpses, excepting to corpses that had been dead for 6 h, which elicited a response. No significant correlation between the removal times and aggressiveness levels were detected in any treatments. It remains to be tested whether this differential response is adaptive in how it influences colony fitness and competition.

Venom alkaloids against Chagas disease parasite: search for effective therapies.

Chagas disease is an important disease affecting millions of patients in the New World and is caused by a protozoan transmitted by haematophagous kissing bugs. It can be treated with drugs during the early acute phase; however, effective therapy against the chronic form of Chagas disease has yet to be discovered and developed. We herein tested the activity of solenopsin alkaloids extracted from two species of fire ants against the protozoan parasite Trypanosoma cruzi, the aetiologic agent of Chagas disease. Although IC50 determinations showed that solenopsins are more toxic to the parasite than benznidazole, the drug of choice for Chagas disease treatment, the ant alkaloids presented a lower selectivity index. As a result of exposure to the alkaloids, the parasites became swollen and rounded in shape, with hypertrophied contractile vacuoles and intense cytoplasmic vacuolization, possibly resulting in osmotic stress; no accumulation of multiple kinetoplasts and/or nuclei was detected. Overexpressing phosphatidylinositol 3-kinase-an enzyme essential for osmoregulation that is a known target of solenopsins in mammalian cells-did not prevent swelling and vacuolization, nor did it counteract the toxic effects of alkaloids on the parasites. Additional experimental results suggested that solenopsins induced a type of autophagic and programmed cell death in T. cruzi. Solenopsins also reduced the intracellular proliferation of T. cruzi amastigotes in infected macrophages in a concentration-dependent manner and demonstrated activity against Trypanosoma brucei rhodesiense bloodstream forms, which is another important aetiological kinetoplastid parasite. The results suggest the potential of solenopsins as novel natural drugs against neglected parasitic diseases caused by kinetoplastids.

Fire Ant Venom Alkaloids Inhibit Biofilm Formation.

Biofilm formation on exposed surfaces is a serious issue for the food industry and medical health facilities. There are many proposed strategies to delay, reduce, or even eliminate biofilm formation on surfaces. The present study focuses on the applicability of fire ant venom alkaloids (aka 'solenopsins', from Solenopsis invicta) tested on polystyrene and stainless steel surfaces relative to the adhesion and biofilm-formation by the bacterium Pseudomonas fluorescens. Conditioning with solenopsins demonstrates significant reduction of bacterial adhesion. Inhibition rates were 62.7% on polystyrene and 59.0% on stainless steel surfaces. In addition, solenopsins drastically reduced cell populations already growing on conditioned surfaces. Contrary to assumptions by previous authors, solenopsins tested negative for amphipathic properties, thus understanding the mechanisms behind the observed effects still relies on further investigation.

Queen venom isosolenopsin A delivers rapid incapacitation of fire ant competitors.

Fire ant venom contains insecticidal alkaloids named 'solenopsins'. Whilst species-specific differences are reported, little attention has been given to caste-specific venom adaptations. The venom of fire ant queens has remained particularly poorly studied, though studies have shown it to be strikingly similar across different species, in being primarily composed of the alkaloid isosolenopsin A, regardless of the chemical configuration in workers. We predict that this is the evolutionary outcome of stabilising selection, implying that a shared mechanism is responsible for the conserved venom composition among fire ant queens. The present investigation tests whether venom plays a role in nest founding, when queens must succeed in isolation in the field against competitor species. Here, we report that fire ant queen venom and isosolenopsin A are faster to incapacitate alien ants than the venom of fire ant workers. Representative sympatric competitor ant species were selected and exposed on their heads to the venom of workers and queens of the invasive fire ant species Solenopsis invicta and S. geminata. Queen venom was found to incapacitate rival foragers quicker than worker venom. The effects were reproduced using synthetic solenopsins, establishing that solenopsin A analogues are particularly effective contact neurotoxins. Overall, the venom of S. invicta is more lethal than of S. geminata, regardless of the incapacitation speed. We believe these are fundamental aspects of the chemical ecology of the invasive ants which remain overlooked, and emphasise the need for further studies into the venom biology of founding queens.

The allergic response mediated by fire ant venom proteins.

Fire ants are widely studied, invasive and venomous arthropod pests. There is significant biomedical interest in immunotherapy against fire ant stings. However, mainly due to practical reasons, the physiological effects of envenomation has remained poorly characterized. The present study takes advantage of a recently-described venom protein extract to delineate the immunological pathways underlying the allergic reaction to fire ant venom toxins. Mice were injected with controlled doses of venom protein extract. Following sensitization and a second exposure, a marked footpad swelling was observed. Based on eosinophil recruitment and production of Th2 cytokines, we hereby establish that fire ant proteins per se can lead to an allergic response, which casts a new light into the mechanism of action of these toxins.

Host Plant-Mediated Interactions Between 'Candidatus Liberibacter asiaticus' and Its Vector Diaphorina citri Kuwayama (Hemiptera: Liviidae).

The Diaphorina citri Kuwayama (Hemiptera: Liviidae) also known as Asian citrus psyllid transmits 'Candidatus Liberibacter asiaticus' (CLas) associated with the citrus Huanglongbing (HLB). Minimizing Asian citrus psyllid populations is one of the most important methods for HLB control. The development and survival of Asian citrus psyllid were evaluated on CLas+ and CLas- plants of Citrus reticulata Blanco. cv. Mashuiju (Sapindales: Rutaceae) or Citrus sunki Hort. ex Tanaka (Sapindales: Rutaceae) to assess the effects of CLas infection on vector populations. The development times were unaffected between CLas+ and CLas- plants for eggs and first to third instar nymphs but decreased for fourth instars, fifth instars, and total nymphal life on CLas+ plants. The survival rates of eggs and first and second instar nymphs were significantly lower, while those of third to fifth instar nymphs were significantly higher on CLas+ plants. However, overall nymphal survival did not differ between CLas+ and CLas- plants. The pre-oviposition period of Asian citrus psyllid on CLas+ plants decreased, while oviposition period increased, resulting in significantly higher fecundity and population trend index compared with those on CLas- plants, illustrating an overall fitness benefit of CLas infection to Asian citrus psyllid. On the other hand, the longevity and resistance to starvation and lower temperatures of adults from CLas+ plants were significantly lower than those from CLas- plants suggesting that there may be a fitness cost for Asian citrus psyllid on CLas+ plants. The development time of eggs and nymphs and adult longevity were always shorter on C. reticulata regardless of infection status. This knowledge of host plant, pathogen, and vector interactions is useful for developing Asian citrus psyllid-HLB management programs.

Gas-chromatography and UV-spectroscopy of Hymenoptera venoms obtained by trivial centrifugation.

This paper summarises gas-chromatography (GC-MS) and preliminary UV-spectroscopy analyses data of fresh, unmodified venom of aculeate hymenopterans (ants, bees, wasps), mainly focusing on red imported fire ants. No solvents nor fractionation were used at any point, which is a novel approach to describing integral toxins cocktails as proposed by Fox et al. (2018a) [1] 10.1016/j.toxicon.2018.02.050 where these results are discussed in deeper details. Herein we focus on further characterising the obtained venom extracted through a novel approach. Pertaining raw data is accessible from Fox et al. (2018b) [2] 10.17632/cpnscw2gkc.1 including further relevant information regarding the used insects, machinery settings, chemical standards.

Host and environmental factors influencing 'Candidatus Liberibacter asiaticus' acquisition in Diaphorina citri.

BACKGROUND: Diaphorina citri is a vector of 'Candidatus Liberibacter asiaticus' (CLas) associated with citrus Huanglongbing. In this study, the infection and titers of CLas in the psyllid, were monitored for life cycle stage, sex, host-plant CLas titer, host-plant genotype, and ambient temperature. RESULTS: Acquisition efficiency of CLas by D. citri was highest in nymphs reared at 25 °C on a host plant with high CLas titers but was independent of the host genotypes assessed and of vector sex. We further observed that D. citri nymphs acquired CLas more rapidly than adults based on acquisition access periods (AAPs). CLas did not multiply in the alimentary canal, hemolymph, and salivary glands of adults for 18 days after a 3-day AAP as adult. However, CLas multiplication was detected in hemolymph and salivary gland of adults after the bacterium was acquired by nymphs. Eighty percent of salivary glands of adults contained CLas 18 days after a 3-day AAP as nymph compared to 10% 18 days after a 3-day AAP as adults. CONCLUSION: Different factors tested herein influenced CLas acquisition efficiency of D. citri, CLas multiplication and spread inside the psyllid. These observations serve to better understand mechanisms of CLas infection in D. citri. © 2018 Society of Chemical Industry.

Speedy milking of fresh venom from aculeate hymenopterans.

A straightforward method for extracting aculeate arthropod venoms by centrifugation is described, based on adapting a glass insert containing a piece of metal mesh or glass wool into a centrifuge tube. Venom apparatuses are centrifuged for 30 s intervals at ≈2000-6000 g, with samples being dislodged between cycles. Venom from fire ants, honeybees, and a social wasp were extracted within minutes. The method is suited for small-scale bioassays and allows for faithful descriptions of unmodified toxin cocktails.