Ceratitis Capitata Research Articles

Competition Between the Mediterranean Fruit Fly, Ceratitis capitata, and the Peach Fruit Fly, Bactrocera zonata Under the Agricultural Ecosystem in Central Iraq

The fruit fly is found all over the world. Ceratitis capitata and the peach fruit fly Bactrocera zonata are among the most damaging fruit pests in the world, causing serious economic and environmental losses and damages. The study was carried out in the Baghdad province in the locations of Al-Taji and Al-Rashidiyah to determine the seasonal presence of C. capitata and B. zonata. Males were trapped using sexual pheromone traps. The results showed that B. zonata flies collected in traps had higher population densities than C. capitata flies. The findings also revealed that the presence of B. zonata was highest in mid-November and lowest in February and March. The results show that, unlike C. capitata, B. zonata can endure high temperatures. The study’s findings revealed a competitive displacement of B. zonata at the expense of C. capitata, whose presence reduced over the study season, which lasted from 1/3/2022 to 15/2/2023. This type of research aids in understanding the time map of these pests, which aids in anticipating the times of their appearance, allowing farmers to select the most optimal times for economically feasible treatment and when the pests approach crucial economic limitations. At the same time, it will supply essential data to interested parties, researchers, and companies that can be used in future studies.

Interference of tritrophic (grape × medfly × parasitoid) interactions by mineral and biomaterial films.

Fruit fly infestation is one of the main obstacles to the exportation of fresh agricultural produce. Films of mineral particles and biomaterials have the potential to protect fruits against tephritid fruit fly infestation. The present study evaluated the effects of particle films on the tritrophic interactions of grape (Vitis vinifera L.), the fruit fly Ceratitis capitata (Wiedemann) and the parasitoid Diachasmimorpha longicaudata (Ashmead) under semi-field conditions. Grapes were biometrically characterised (i.e. colour, firmness, mass, length and diameter), treated with mineral particles, biomaterials or distilled water (control), and then used in oviposition and parasitism bioassays. In the oviposition bioassay, the treated grapes were exposed to 50 C. capitata pairs in field cages, and after 48 h, the punctures and eggs on each fruit were counted. In the parasitism bioassay, treated grapes were artificially infested with third-instar C. capitata larvae (two per fruit), exposed (2 h) to 50 D. longicaudata pairs in field cages to determine parasitism index, larval and pupal viabilities and number of flies and parasitoids emerged. Treatment with the mineral film affected fruit colour and reduced C. capitata oviposition but failed to significantly affect the parasitism capacity of D. longicaudata. The ability of the parasitoid to locate and parasitise C. capitata larvae in kaolin-coated fruits suggests that kaolin films could be used in conjunction with biological agents to control fruit flies.

Can the use of particle films for fruit protection against medfly alter the behavior of the parasitoid Diachasmimorpha longicaudata?

AbstractThe use of particle films, especially kaolin‐based films, is a promising technology to control infestations of Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), an important pest of fruits. However, its effects on one of the most important biocontrol agents of this fly in Brazil, the parasitoid Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae), are unknown. This study aimed to evaluate the influence of mineral particle films on the oviposition behavior of D. longicaudata and to determine the success of parasitism in C. capitata using grape (Vitis vinifera L., Vitaceae) as substrate. Before the bioassays, the color characteristics, firmness, total soluble solid content, pH, and titratable acidity of the fruits were determined. Grapes were immersed in suspensions of kaolin Surround WP, kaolin 607, kaolin 608, and distilled water (control); thereafter, they were perforated, and two C. capitata third instars were inserted into the orifice. The grapes were then exposed to a female parasitoid. The frequency and duration of the following behavioral parameters of D. longicaudata were evaluated: landing on fruit, inspection, buccal contact, oviposition, cleaning, resting on fruit, and resting on cage. Furthermore, parasitism success was assessed. Mineral particle films altered the color and firmness of the grapes. The females of D. longicaudata performed all distinguished behaviors in treated and untreated grapes, except buccal contact, which was not done on the kaolin‐treated fruits. Kaolin 607 negatively affected landing, inspection, puncture, and rest behaviors; kaolin Surround WP only reduced inspection and puncture. Fruit coating with all three tested kaolin products decreased the success of parasitism of D. longicaudata, indicating that particle films applied to plant organs can affect the behavior of this natural enemy.

Shadow Effect for Small Insect Detection by W-Band Pulsed Radar.

In radar entomology, one primary challenge is detecting small species (smaller than 5 cm) since these tiny insects reflect radiation that can be poorly observable and, therefore, difficult to interpret. After a literature search on radar entomology, this research found few works where it has been possible to sense insects with dimensions smaller than 5 cm using radars. This paper describes different methodologies to detect Mediterranean fruit flies with 5-6 mm sizes using a pulsed W-band radar and presents the experimental results that validate the procedures. The article's main contribution is the successful detection of Mediterranean fruit flies employing the shadow effect on the backscattered radar signal, achieving an 11% difference in received power when flies are present. So far, according to the information available and the literature search, this work is the first to detect small insects less than 1 cm long using a pulsed radar in W-Band. The results show that the proposed shadow effect is a viable alternative to the current sensors used in smart traps, as it allows not only detection but also counting the number of insects in the trap.

Immunodetection of Truncated Forms of the α6 Subunit of the nAChR in the Brain of Spinosad Resistant Ceratitis capitata Phenotypes.

The α6 subunit of the nicotinic acetylcholine receptor (nAChR) has been proposed as the target for spinosad in insects. Point mutations that result in premature stop codons in the α6 gene of Ceratitis capitata flies have been previously associated with spinosad resistance, but it is unknown if these transcripts are translated and if so, what is the location of the putative truncated proteins. In this work, we produced a specific antibody against C. capitata α6 (Ccα6) and validated it by ELISA, Western blotting and immunofluorescence assays in brain tissues. The antibody detects both wild-type and truncated forms of Ccα6 in vivo, and the protein is located in the cell membrane of the brain of wild-type spinosad sensitive flies. On the contrary, the shortened transcripts present in resistant flies generate putative truncated proteins that, for the most part, fail to reach their final destination in the membrane of the cells and remain in the cytoplasm. The differences observed in the locations of wild-type and truncated α6 proteins are proposed to determine the susceptibility or resistance to spinosad.

RNAi-mediated silencing of Mediterranean fruit fly (Ceratitis capitata) endogenous genes using orally-supplied double-stranded RNAs produced in Escherichia coli.

The Mediterranean fruit fly (medfly), Ceratitis capitata Wiedemann, is a major pest affecting fruit and vegetable production worldwide, whose control is mainly based on insecticides. Double-stranded RNA (dsRNA) able to down-regulate endogenous genes, thus affecting essential vital functions via RNA interference (RNAi) in pests and pathogens, is envisioned as a more specific and environmentally-friendly alternative to traditional insecticides. However, this strategy has not been explored in medfly yet. Here, we screened seven candidate target genes by injecting in adult medflies gene-specific dsRNA hairpins transcribed in vitro. Several genes were significantly down-regulated, resulting in increased insect mortality compared to flies treated with a control dsRNA targeting the green fluorescent protein (GFP) complementary DNA (cDNA). Three of the dsRNAs, homologous to the beta subunit of adenosine triphosphate (ATP) synthase (ATPsynbeta), a vacuolar ATPase (V-ATPase), and the ribosomal protein S13 (RPS13), were able to halve the probability of survival in only 48 h after injection. We then produced new versions of these three dsRNAs and that of the GFP control as circular molecules in Escherichia coli using a two-self-splicing-intron-based expression system and tested them as orally-delivered insecticidal compounds against medfly adults. We observed a significant down-regulation of V-ATPase and RPS13 messenger RNAs (mRNAs) (approximately 30% and 90%, respectively) compared with the control medflies after 3 days of treatment. No significant mortality was recorded in medflies, but egg laying and hatching reduction was achieved by silencing V-ATPase and RPS13. In sum, we report the potential of dsRNA molecules as oral insecticide in medfly. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Biological diversity of arthropods associated with two varieties of pepper (<i>Capsicum annuum</i> L., 1753) at Nkolmelen (Yaoundé, Cameroon)

Pepper is a vegetable which plays an important role in the human diet and health. Many insects attack this plant and decrease its production in the absence of appropriate phytosanitary treatment. Thus, the objective of the present study was to record the arthropods associated with the yellow and red pepper varieties. For this purpose, weekly observations were conducted during two cropping cycles on 192 plants, using a completely randomized device. As results, the fauna of the pepper was very diverse and stable (specific richness 47 and Equitability index 0.86). The yellow pepper was the most sensitive with an average of nine insect species per plant versus eight on the red pepper. These insects belonged to seven orders (Arachnida, Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera and the Orthoptera), 28 families and 47 species. The densest orders were Diptera represented by Ceratitis capitata, Silba capsicarum, followed by Hymenoptera were represented by Camponotus floridanus, Camponotus acvapimensis and Crematogaster sp. and Hemiptera represented by Aphis gossypii, Macrosiphum euphorbiae, Pseudococcus sp. The present study provided a database on arthropodofauna of the pepper plant. This is of paramount importance for the development of healthy and sustainable protection strategies among pepper producers in order to improve national production.

Learning algorithms estimate pose and detect motor anomalies in flies exposed to minimal doses of a toxicant

Pesticide exposure, even at low doses, can have detrimental effects on ecosystems. This study aimed at validating the use of machine learning for recognizing motor anomalies, produced by minimal insecticide exposure on a model insect species. The Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), was exposed to food contaminated with low concentrations of Carlina acaulis essential oil (EO). A deep learning approach enabled fly pose estimation on video recordings in a custom-built arena. Five machine learning algorithms were trained on handcrafted features, extracted from the predicted pose, to distinguish treated individuals. Random Forest and K-Nearest Neighbor algorithms best performed, with an area under the receiver operating characteristic (ROC) curve of 0.75 and 0.73, respectively. Both algorithms achieved an accuracy of 0.71. Results show the machine learning potential for detecting sublethal effects arising from insecticide exposure on fly motor behavior, which could also affect other organisms and environmental health.

Differential Cold Tolerance on Immature Stages of Geographically Divergent Ceratitis capitata Populations.

Cold tolerance of adult medflies has been extensively studied but the effect of subfreezing temperatures on the immature stages remains poorly investigated, especially as far as different populations are regarded. In this study, we estimated the acute cold stress response of three geographically divergent Mediterranean fruit fly populations originating from Greece (Crete, Volos) and Croatia (Dubrovnik) by exposing immature stages (eggs, larvae, pupae) to subfreezing temperatures. We first determined the LT50 for each immature stage following one hour of exposure to different temperatures. Then eggs, larvae and pupae of the different populations were exposed to their respective LT50 for one hour (LT50 = -11 °C, LT50 = -4.4 °C, LT50 = -5 °C for eggs, larvae and pupae, respectively). Our results demonstrate that populations responded differently depending on their developmental stage. The population of Dubrovnik was the most cold-susceptible at the egg stage, whereas in that of Crete it was at the larval and pupal stage. The population of Volos was the most cold-tolerant at all developmental stages. The egg stage was the most cold-tolerant, followed by pupae and finally the 3rd instar wandering larvae. This study contributes towards understanding the cold stress response of this serious pest and provides data for important parameters that determine its successful establishment to unfavorable environments with an emphasis on range expansion to the northern, more temperate regions of Europe.

Optimization of Brewer's Yeast Quantity in Liquid and Gel Larval Diets for the Mediterranean Fruit Fly.

Several artificial larval diets have been developed, evaluated and used for mass-rearing of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) (Diptera: Teprhitidae). There are several efforts to reduce the cost of rearing and optimize the quality of the produced sterile males that are destined for release in sterile insect release programs. Survival, growth, longevity and reproductive capacity of sterile males are strongly connected with the most expensive ingredient, the brewer's yeast (protein), in the larval diet. The current study focused on settling the optimal content of brewer's yeast in a liquid diet and a gel diet. Egg hatch rates, developmental duration of immatures, pupation rate, pupae and adult survival were recorded as indicators of quantity and quality of the produced adults. Egg hatch was higher and larval developmental duration longer in the gel diet. In contrast to the liquid diet, an increase in brewer's yeast concentration was correlated with increased pupation rate and pupae survival in the gel diet. Reducing brewer's yeast up to 50% of its initial quantity had no significant effect on the survival of the emerging adults regardless of the diet type. Our findings may contribute to the production of low-cost and effective diets for use in mass-rearing facilities of medflies.

Smart insect monitoring based on YOLOV5 case study: Mediterranean fruit fly Ceratitis capitata and Peach fruit fly Bactrocera zonata

The agricultural sector in Egypt is adversely affected by factors such as inadequate soil fertility and environmental hazards such as pestilence and diseases. The implementation of early pest prediction techniques has the potential to enhance agricultural yield. Bactrocera zonata and Ceratitis capitata, known as peach fruit fly and Mediterranean fruit fly, respectively, are the predominant pests that cause significant damage to fruits on a global scale. The present study proposes a deep learning-based approach for the detection and quantification of pests. The proposed approach entails the retrieval of data pertaining to the adhesive trap condition, followed by its examination and presentation through a mobile application. The YOLOV5 model has been implemented for the purpose of pest classification, localization, and quantification. In order to address the issue of a restricted dataset, a hybrid technique of transfer learning and data augmentation (copy and paste) was employed. The proposed approach offers an intelligent real time pest detection, thereby facilitating the prediction of treatment options. An application for smartphones has been developed to aid farmers and agricultural professionals in the management and treatment of pests. The proposed approach has the potential to aid farmers in identifying the existence of pests, thereby diminishing the duration and resources needed for farm inspection. As per the results of the conducted experiments, the proposed approach demonstrates a noteworthy increase in performance. The weighted average accuracy reaches 84%, while precision (P), mean average precision (mAP), and F1-score show enhancements of up to 15%, 18%, and 7% respectively.

Boric Acid as a Safe Insecticide for Controlling the Mediterranean Fruit Fly Ceratitis Capitata Wiedemann (Diptera: Tephritidae)

In promising experiments, boric acid has been tested as a safe and environmentally friendly insecticide for controlling Ceratitis capitata Wiedeman, a mediterranean fruit fly diptera belonging the Tephritidae family. Obtaining encouraging results can partially solve insecticidal pollution caused by chemical insecticides. Boric acid was applied in five baits that were, water, 5 and 10% sugar solutions, and 2.5 and 5% protein solutions on just emerged and 24-hour-old flies. For each bait, boric acid was presented by successive concentrations of 0.5%, 1%, 1.5%, and 2%. After 24 hours, the aged-fly death percentage ranged from 12.2 to 69.4 % and from 48 to 99.4% after 48 hours for just-emerged flies. However, for 24-hour-old flies, the percentage of death ranged from 32.6 to 90.4% after 24 hours and 65 to 99.6% after 48 hours. The current study shows the existence of a a direct proportionality between death percentage and the concentration of boric acid in the five baits, as death percentage increased with boric acid concentration. In addition, different baits had some effect on death percentage, but without a noticeable correlation. To avoid direct contact with the host plant and the boric acid-based baits, it is strongly encouraged to utilize boric acid in medfly control methods like the mass trapping technique.

Prioritisation of quarantine pest list for the Caribbean using a multi-criteria decision approach

Quarantine plant pests are socially, economically and environmentally important due to their impact on food security, human health, global trade and crop production costs. The increase in global trade and tourism, frequent occurrence of natural disasters and climate changes have exacerbated the rate of entry, establishment and spread of plant pests regionally and globally. It has, therefore, become exigent to develop a list of pests of quarantine importance at the regional and national levels to prioritise and allocate the limited available resources to manage the associated risks. In the present study, the Technical Committee on the Formulation and Prioritisation of a Regional Priority Pest List for the Caribbean, in collaboration with the National Plant Protection Organisation of the Caribbean countries and the United States Department of Agriculture - Animal and Plant Health Inspection Service (USDA-APHIS), developed and prioritised a quarantine pest list using a multi-criteria decision-making approach. The technical committee successfully evolved the process in 2014 and 2018 and developed a list of the top 10 pests of quarantine importance for the Caribbean Region, employing the Delphi Technique (DT) and Analytical Hierarchy Process (AHP) through the assignment of criteria that are relevant to the region. The Mediterranean fruit fly (Ceratitis capitata), frosty pod rot (Moniliophthora roreri) and the tomato leaf miner (Tuta absoluta), listed as top quarantine pest threats, were subsequently detected in the region. This exercise guided the authorities in advance to allocate resources and to develop response plans including capacity building for surveillance and detection of priority pests. This has demonstrated the significance and appropriateness of the multi-criteria decision approach to determine priority pest lists and prepare the region for development of better management practices.

Differential responses of Ceratitis capitata to infection by the entomopathogenic fungus Purpureocillium lilacinum.

The medfly Ceratitis capitata is one of the most damaging fruit pests with quarantine significance due to its extremely wide host range. The use of entomopathogenic fungi constitutes a promising approach with potential applications in integrated pest management. Furthermore, developing insect control methods can involve the use of fungal machinery to cause metabolic disruption, which may increase its effectiveness by impairing insect development. Insect species, including C. capitata, relies on reproduction potential, nutrient reserves, metabolic activities, and immune response for survival. Accordingly, the purpose of this study was to investigate the impacts of the entomopathogenic fungus Purpureocillium lilacinum on C. capitata pre-mortality. The medfly V8 strain was subjected to laboratory bioassays, which consisted on determining the virulence of P. lilacinum on the medfly. Purpureocillium lilacinum was applied on abdominal topical of 5-day-old males and females. Following the fungal inoculation, we have confirmed (i) a significant increase in tissue sugar content, (ii) a significant decrease in carbohydrase activities, digestive glycosyl hydrolase, and proteinase activities in whole midguts of treated flies, (iii) the antimicrobial peptides (AMPs) genes expression profile was significantly influenced by fly gender, fly status (virgin, mature, and mated), and time after infection, but infection itself had no discernible impact on the AMPs for the genes that were examined. This study provides the first insight into how P. lilacinum could affect C. capitata physiological mechanisms and provides the foundation for considering P. lilacinum as a novel, promising biocontrol agent.

Natural Oil Lure Outperforms Trimedlure in Capturing Males of the Mediterranean Fruit Fly, Ceratitis capitata (Diptera: Tephritidae).

Females of certain tephritid fruit fly species (Diptera: Tephritidae) pose an enormous agricultural threat, as they oviposit in commercially important fruits and vegetables. Trapping networks are often operated in fruit fly-free areas to detect incipient infestations. Trapping relies largely on male attractants, so-called male lures, with trimedlure (TML) being used to detect invasive Ceratitis spp. Operating large-scale surveillance programs incurs substantial costs for both supplies and labor, and the problem is exacerbated by the fact that trimedlure (as well as other male lures) is effective for relatively short intervals in the field (6-8weeks). Because frequent servicing increases costs, there is considerable interest in modifying existing lures or developing new formulations to extend their effective field longevity. Here, we present results of a field study in Hawaii on a wild population of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), that compared male captures in traps baited with (i) fresh liquid TML, (ii) TML plugs, (iii) a novel controlled-release TML sachet, and (iv) a novel natural oil blend dispensed from a sachet. Catch was recorded weekly for 12weeks and then at 16 and 20weeks, with 12 traps deployed per treatment. The natural oil formulation, which contains the natural plant product α-copaene, was as effective as the fresh liquid TML even after weathering for 20weeks. Future work will focus on developing a dispenser for this formulation that is compatible with standard trap design and deployment.

Development of a Hydrothermal Treatment to Control Fruit Flies (Diptera: Tephritidae) and Maintain the Quality of ‘Fuyu’ Persimmons

Because of fruit fly incidence, importing countries impose phytosanitary barriers to prevent the entry and spread of infested fruits. When fruits are not grown in fruit fly-free areas, some countries require quarantine treatments for fruit disinfestation before or during shipping. The objective of this study was to evaluate the use of a hydrothermal treatment as a quarantine treatment for ‘Fuyu’ persimmons infested with two fruit fly species to maintain fruit quality. Hot water treatment (HWT) was applied to eggs and third-instar larvae of Ceratitis capitata and Anastrepha fraterculus in vitro at 42º, 44º, 46º, 48º, and 50 ºC for 20, 30, 40, 50, 60, and 90 min. Persimmon fruit infested by C. capitata and A. fraterculus eggs and third-instar larvae were subjected to 44 ºC for 60 and 90 min, 46 °C for 20 and 30 min; and 48 °C for 20 min. Untreated infested fruits were used to estimate the rate of fruit fly infestation. Pulp firmness, skin and pulp colors, titratable acidity, pH, and total soluble solids were measured to evaluate the effect of HWT on fruit quality. The increase in temperature and immersion time decreased the pupation and emergence of adults of C. capitata and A. fraterculus in vitro. C. capitata eggs treated in vitro at temperatures ≥ 46 ºC for 30 min did not produce pupae. A. fraterculus eggs treated in vitro at 46 ºC for 20 min exhibited no larval hatching. No pupae were obtained from third-instar larvae of both fruit fly species treated at 44 ºC for 60 min. Infested ‘Fuyu’ persimmons treated at 44 ºC for 90 min did not exhibit the emergence of adults of C. capitata or A. fraterculus. Except for pH, in general, ‘Fuyu’ persimmons subjected to HWT demonstrated no alterations of skin or pulp texture, skin coloration, titratable total acidity, or total soluble solids. The results suggest that HWT is a potential quarantine treatment for the export of ‘Fuyu’ persimmons.

Influência da recópula na técnica do inseto estéril em Ceratitis capitata (Diptera: Tephritidae): uma abordagem molecular

ABSTRACT The Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), is one of the most harmful species to world horticulture, thus requiring suppression or eradication programs. The sterile insect technique is widely used for autocidal control of nuisance insects because it neither releases exotic agents into the environment nor introduces new genetic material into existing populations. In 2005, the Moscamed Brasil biofactory imported the tsl Vienna 8 C. capitata strain from the International Atomic Energy Agency (IAEA); this action required genetic testing of the strain’s biological characteristics. The objective of this study was to discriminate males of wild populations from tsl Vienna 8 using molecular markers, and to conclude which male line dominated in a remating condition. Four crosses, each using 100 males and 100 females, were performed: wild female × wild male; wild female × tsl Vienna 8 male; wild female × wild male, followed by remating with tsl Vienna 8 males after 48 h, and wild female × tsl Vienna 8 male, followed by remating with wild males after 48 h. The results showed that the tsl Vienna 8 strain is compatible with wild females from the São Francisco Valley region and that these males can successfully transfer their sperm to the female spermathecae. Regarding remating, the sperm of the second male dominated over that of the first one. Based on these findings, the sterile insect technique success may be reduced, since the progeny of a female that remates with a wild male could be viable.

Early detection of the Mediterranean Fruit Fly, Ceratitis capitata (Wied.) in oranges using different aspects of remote sensing applications

Mediterranean Fruit Fly, Ceratitis capitata (Diptera: Tephritidae) is regarded as an important pest of orange (Citrus). Early detection of pest infestations enables theoptimal application of preventative and control measures. This study was carried out under laboratory conditions, in order to predict and monitor orange pest infestations. Consequently, the scope was to find a remote sensing application that can help in the prediction of Mediterranean Fruit Fly infestation in oranges with the least loss in production. Spectroscopic and thermal imaging techniques were investigated, as effective tools in determination of pest infestation and damage in orange fruits. According to the findings, the optimum spectral zones that can be used to discriminate and differentiate between healthy (non-infected) orange fruit and infected ones were red and near infrared bands. Six vegetation indices were calculated to analyze the Field Spectral measurements. By calculating the NPCI (Normalized Pigment Chlorophyll Index), it was found that NPCI values for infected orange fruits were higher in comparison to healthy ones. Thermal imaging showed that the infected orange fruit temperatures were on average 0.8 °C higher than that of healthy fruits. As the maximum temperature differential (MTD) between healthy and infected fruits were 23.7–24.5 °C, respectively. These spectral reflectance curves were useful for researchers working on Site-specific crop management, as they can use remote sensing to detect individual fruit infections. Also, this technique should be used as a powerful and non-destructive method for assistance in agriculture.

Gut bacterial population and community dynamics following adult emergence in pest tephritid fruit flies

Gut microbiota are important contributors to insect success. Host-microbe interactions are dynamic and can change as hosts age and/or encounter different environments. A turning point in these relationships the transition from immature to adult life stages, particularly for holometabolous insects where there is radical restructuring of the gut. Improved knowledge of population and community dynamics of gut microbiomes upon adult emergence inform drivers of community assembly and physiological aspects of host-microbe interactions. Here, we evaluated the bacterial communities of the pest tephritid species melon fly (Zeugodacus cucurbitae) and Medditeranean fruit fly (medfly, Ceratitis capitata) associated with the pupae life stage and timepoints immediately following adult eclosion. We used a combination of culturing to determine cultivatable bacterial titers, qPCR to determine 16S-rRNA SSU copy numbers, and 16S V4 sequencing to determine changes in communities. Both culturing and qPCR revealed that fly bacterial populations declined upon adult emergence by 10 to 100-fold followed by recovery within 24 h following eclosion. Titers reached ~ 107 CFUs (~ 108 16S rRNA copies) within a week post-emergence. We also observed concurrent changes in amplicon sequence variance (ASVs), where the ASV composition differed overtime for both melon fly and medfly adults at different timepoints. Medfly, in particular, had different microbiome compositions at each timepoint, indicating greater levels of variation before stabilization. These results demonstrate that tephritid microbiomes experience a period of flux following adult emergence, where both biomass and the makeup of the community undergoes dramatic shifts. The host-microbe dynamics we document suggest plasticity in the community and that there may be specific periods where the tephritid gut microbiome may be pliable to introduce and establish new microbial strains in the host.

Toxicological interactions between spinosad and essential oils in the Mediterranean fruit fly, Ceratitis capitata

AbstractIn recent decades, the use of biopesticides for pest management has increased, especially in modern and organic agriculture. Spinosad is a biopesticide approved in many countries for its use against Ceratitis capitata. However, an increasing amount of pest resistance against spinosad had been found in different pest species. In the present study, we propose the use of a combination between essential oils (EOs) and spinosad as a way to contribute to the development of sustainable alternatives, integrating natural substances with anti‐insect properties and reducing the amount of commercial active ingredients by synergistic effects. Our primary objective was to investigate the synergistic potential of EOs and spinosad in order to enhance the insecticidal efficacy against C. capitata adults. We evaluate the toxic effect of the EOs of Baccharis spartioides (Hook), Eucalyptus cinerea (F. Muell. ex Benth) and Schinus areira (Linneo), the bioinsecticide spinosad and their combinations. We evaluated the combined toxicities of EOs from B. spartioides, E. cinerea and S. areira with spinosad and characterized the LD50 of each mixture and each substance administered topically alone on male and female individuals of C. capitata. A synergistic effect was observed for the B. spartioides–spinosad mixture in females and the S. areira–spinosad mixture in both sexes, and an antagonistic effect was found for the B. spartioides–spinosad mixture and the E. cinerea–spinosad mixture in males. Considering these results, we suggest the use of the EO from S. areira combined with spinosad as an alternative way of controlling C. capitata.