ABSTRACT Awareness of the roles of flies as pollinators in natural and agricultural ecosystems has increased considerably in recent years, and there is growing consensus that globally they rank second in importance as floral pollinators after the Hymenoptera. The bristle flies (Tachinidae) are among the most important and ubiquitous flower‐visiting flies, yet relatively few studies have focused on the pollination services of tachinids and there have been no comprehensive studies of the frequency of flower visitation across the family. The goal of this paper is to review the pervasiveness and importance of bristle flies as floral visitors and pollinators. We provide an overview of the prevalence of Tachinidae as floral visitors, highlighting their importance in high elevation (and high latitude) environments, and as visitors of a broad array of plant families, most notably those with relatively short corollas and compound inflorescences. Using information from the iNaturalist database, we find that most tachinid genera visit flowers at least occasionally and many taxa are major floral visitors. The likelihood of floral visitation is found to vary significantly among subfamilies and tribes, with genera in the Phasiinae exhibiting the highest probability of floral visitation. We explore the phylogenetic distribution of floral adapted elongated mouthparts in tachinids, finding that these adaptations have evolved independently well over 20 times across the family and in multiple lineages in every subfamily. We further review patterns and examples of floral specificity within the family and assess the efficacy of tachinids as pollinators with case studies. Finally, we consider the roles of Tachinidae as pollinators in agricultural systems and their potential dual ecological services as both biocontrol agents and pollinators.
ABSTRACT As an environmental stress, ultraviolet B (UV‐B) radiation can directly affect the growth, development and survival of insects. However, the role of cuticular protein in insect response to UV‐B stress remains unknown. The study investigates the critical role of the cuticular protein gene MpCP19a in Myzus persicae under UV‐B stress. Herein, the cuticular protein gene MpCP19a of M. persicae was cloned and identified. Sequence analysis revealed that it contains a typical ChtBD4 functional domain characteristic of the CPR protein family. MpCP19a was expressed in different developmental stages and tissues of M. persicae, with the highest expression in 2nd nymphs, as well as in the head and embryo, and the lowest in 1st nymphs and the gut. The expression level of MpCP19a in aphids was significantly up‐regulated upon UV‐B exposure. When MpCP19a was knocked down by RNAi, the survival rate of M. persicae decreased under UV‐B exposure, accompanied by a significant reduction in body size and the formation of brown pigmentation on the body surface. In contrast, under normal conditions (without UV‑B stress), knockdown of MpCP19a did not significantly affect survival rate, body size, or pigmentation compared with the dsGFP control and negative control group. These results indicate that MpCP19a plays an important role in regulating the growth and development of M. persicae and its molecular response to UV‐B stress, laying a foundation for developing key targets in insect control technologies.
ABSTRACT Insects display a wide range of complex behaviours despite having relatively simple nervous systems, and neuropeptides have emerged as key signalling molecules connecting neural processing with physiological states and behaviours. This review consolidates current understanding of insect neuropeptide systems, focusing on their roles in regulating behaviour and communication, including feeding, reproduction, learning, stress responses, and pheromone‐mediated interactions. We outline the evolutionary origins of neuropeptidergic signalling and highlight how recent advances in genomics, transcriptomics, and peptidomics have expanded knowledge of neuropeptide diversity across both model and pest insects. Rather than providing a mere descriptive inventory, the review examines how major neuropeptide families and their G protein‐coupled receptors influence behavioural decisions and internal state‐dependent responses. We also discuss emerging strategies that target neuropeptide pathways to modify insect behaviour, such as RNA interference, peptidomimetic compounds, and small‐molecule receptor modulators, assessing their potential as selective and environmentally friendly alternatives to conventional insecticides. At the same time, we address present limitations, including functional redundancy, variable responses in field conditions, challenges in delivery and stability, and possible non‐target effects. By integrating molecular, neurobiological, and ecological perspectives, this review emphasizes neuropeptide signalling pathways as promising tools for precise manipulation of insect behaviour and communication. Continued interdisciplinary research will be crucial for translating these concepts into practical, sustainable applications within integrated pest management systems.
ABSTRACT Classical biological control, which is the introduction of natural enemies from an invasive pest's area of origin, has been proposed repeatedly to control the invasive Japanese beetle Popillia japonica Newman (Coleoptera: Scarabaeidae) in invaded areas. In the absence of area‐wide management strategies to control P. japonica in Europe the release of the fly Istocheta aldrichi (Mesnil) (Diptera: Tachinidae) is considered. However, although I. aldrichi has been released in the USA, in Canada, and the Portuguese Azores, no laboratory tests have been done to determine which non‐target host species are suitable for the development of the parasitoid (physiological host range). Thus, as first step of a risk–benefit analysis to assess the potential for the introduction of I. aldrichi to Europe, we investigated the physiological host range of the parasitoid by conducting laboratory‐based no‐choice tests with 14 European non‐target beetle species from three subfamilies of the family Scarabaeidae. As is the case for most parasitoids, we predicted that host acceptance for oviposition and suitability for development of I. aldrichi will decrease with decreasing phylogenetic relatedness to P. japonica . The assessment was done using a sequential exposure scheme, in which P. japonica was exposed before and after the non‐target beetle to ensure oviposition readiness of the parasitoid. Testing revealed that six out of 14 non‐target beetle species were accepted for oviposition by I. aldrichi females. As predicted, this included all three tested beetles within the subfamily Rutelinae, but also one Cetoniinae, and one Melolonthinae. However, successful development of the parasitoid was only found in two Rutelinae: Mimela junii (Duftschmid) and Anomala vitis Fabricius. Based on the information from this study, choice tests and further investigations into the ecological host range of I. aldrichi should be conducted to further analyse the risks of using the fly as a classical biological control agent in Europe.
ABSTRACT Salicylic acid (SA) and jasmonic acid (JA) are key phytohormones regulating induced plant defenses against insect herbivores. Phloem‐feeding insects often activate the SA pathway, although exceptions in which both SA and JA are induced, such as during herbivory by the white mealybug Planococcus citri (Risso) (Hemiptera: Pseudococcidae) on coffee plants, highlight the need to clarify the relative roles of these pathways in modulating plant resistance. This study investigated how activation of the SA and JA pathways in coffee plants, Coffea arabica L. (Rubiaceae), affects direct plant defenses against P. citri and indirect defenses through the emission of volatiles attractive to the predatory lady beetle Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae). Coffee plants were treated with exogenous doses of the phytohormone derivatives methyl salicylate (MeSA) and methyl jasmonate (MeJA). Direct defenses were assessed through P. citri preference and performance assays, whereas indirect defenses were evaluated using olfactory preference assays with C. montrouzieri . Application of MeSA to coffee plants, regardless of dose, increased host preference by P. citri nymphs compared with untreated plants, whereas treatment with MeJA, either alone or in combination with MeSA, particularly at higher doses, reduced herbivore preference. Treatment with any of the elicitors, irrespective of dose, delayed P. citri development, particularly on plants treated with MeJA alone. MeJA also induced indirect defenses, with or without P. citri infestation, triggering the emission of volatiles attractive to C. montrouzieri , whereas MeSA treatment reduced the attractiveness of plant volatiles to the predator. The combination of MeSA and MeJA in mealybug‐infested plants also reduced plant attractiveness to the lady beetle. Overall, activation of the jasmonate pathway played an important role in both direct and indirect defenses against the mealybug, whereas activation of the salicylate pathway produced inconsistent effects on direct defenses and did not regulate indirect defenses.
ABSTRACT Females of many insect species do not care for their offspring after oviposition, and are expected to maximize their fitness by laying eggs on sites suitable for offspring survival and performance. The relationship between female oviposition and offspring performance has been widely examined in phytophagous insects, but its patterns vary by species and ecological context. Physical traits of host plants, such as leaf toughness, as well as chemical characteristics, may influence this preference–performance relationship and drive the adaptation of species‐specific larval feeding traits. In this study, we investigated oviposition site selection, egg and larval morphology, and hatchling performance in two sympatric swallowtail butterflies, Papilio xuthus Linnaeus and Papilio memnon Linnaeus (Lepidoptera: Papilionidae), that utilize Citrus trees as host plants. Our field work indicated that P. xuthus females tended to oviposit on smaller leaves located near branch tips, whereas P. memnon females laid eggs on larger leaves inside the canopy. Laboratory experiments revealed that P. memnon hatchlings had larger head capsules relative to egg size and larger mandibles relative to head size, and that their survival rates were higher, even on tough old leaves, than those of P. xuthus . These results suggest that the species have evolved unique relationships between maternal oviposition site selection and hatchling feeding traits in response to the microenvironments of their host plants.
ABSTRACT Actia interrupta (Diptera: Tachinidae) is an important larval parasitoid of the eastern spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae), especially during low‐density (endemic) population phases. Despite its ecological importance, information on its basic biology remains limited. In a laboratory study, we described the morphology and development of immature stages, measured the duration of development at different temperatures, adult longevity, and the temporal dynamics of egg and larval maturation in females. Females were confirmed to be larviparous, larvipositing first‐instar larvae following a post‐copulation gestation period. The parasitoid develops through three larval instars, with the final instar forming a secondary respiratory funnel within the host prior to egression. Development time decreased with increasing temperature, while adult longevity was not affected by sex or mating status. Behavioral assays showed that females preferentially flied, landed, and larviposited on substrates containing hosts, supporting an indirect larviposition strategy. Finally, we demonstrate for the first time that the oblique‐banded leafroller, Choristoneura rosaceana (Lepidoptera: Tortricidae), serves as a suitable overwintering host for A. interrupta . These results provide key biological insights into a parasitoid species contributing to the regulation of low‐density spruce budworm populations.
ABSTRACT The order Hymenoptera, which has ~160 000 described species, is the largest within the class Insecta, in which all members are capable of parthenogenesis. This review represents a synthesis of the previously existing and new reports and hypotheses on different cases and mechanisms of parthenogenesis in Hymenoptera, including genetic and cytological aspects of sex determination as well as the role of specific bacterial symbionts. Arrhenotokous parthenogenesis and haplodiploidy are likely to represent two key ancestral genetic features of this order. Multiple independent transitions to diploid, and, occasionally, to triploid thelytoky took place across different hymenopteran clades. Arrhenotoky, that is, haploid males and diploid females respectively developing from unfertilized and fertilized eggs, is implemented in Hymenoptera either through single‐locus (or sometimes multiple‐locus) complementary sex determination (CSD) or, at least in some taxa with high levels of inbreeding, via genomic imprinting. Similarly to other insects, sex determination in this order is performed by specific gene cascades, with transformer and doublesex usually being the main master and actuator genes, respectively. In a few special cases, males are produced through paternal genome elimination. Thelytoky in Hymenoptera can be sporadic, facultative or obligate, and, in terms of the presence/absence of the reductional meiotic division, either automictic or apomictic. Different types of automixis in this order include gamete duplication as well as central or terminal fusion. Arrhenotoky and thelytoky can coexist within the same species, whereby thelytokous individuals sometimes become intraspecific social parasites. Thelytoky in Hymenoptera, usually in the form of gamete duplication, is often induced by endosymbiotic microorganisms, and this type of parthenogenesis is almost exclusively restricted to parasitoids. These endosymbionts must therefore possess specific genes which ensure both egg diploidization and feminization of the developing individual, either in the form of one‐step or, more frequently, two‐step thelytoky. Although recent data and hypotheses significantly contribute to our understanding of hymenopteran reproduction, a number of questions deserve further investigation.
ABSTRACT Insects have evolved a wide range of innate immune responses as a result of the variety of substrates they consume and the settings in which they reside. For this reason, they represent a nearly limitless source of biologically active compounds that possess unparalleled applications. Of particular interest in our current review are the lectins, the key elements of membrane‐bound or extracellular pattern‐recognition receptors (PRRs). Lectins are proteins that specifically recognize and interact with glycans non‐covalently. Besides their crucial role in insect immunity, lectins are at the pinnacle of research owing to their prospective applications. This is attributed to their capacity to discern subtle variations in the cell surface carbohydrate structures that are crucial for protein‐carbohydrate recognition. This review focuses on emerging trends in research on insect lectins with the objective of emphasizing the significance of further investigation that can perhaps help in the exploration of their probable applications.
ABSTRACT Diptera form one of the most diverse and functionally important insect groups, yet their ecological contributions to biodiversity maintenance and ecosystem services remain underrecognized and underrepresented in research and conservation planning. This review was undertaken to synthesize current evidence on the functional ecology of Diptera, highlight their roles in pollination services and biological control and identify knowledge gaps that limit their integration into biodiversity conservation and ecosystem management. A systematic search of peer‐reviewed articles was conducted by analyzing 83 studies from 114 screened sources. The review reveals that Diptera contribute substantially to pollination and biological control. They visit approximately 72% of the world's major crops and dominate pollination networks in alpine, arctic and shaded habitats where bees are scarce. Several families of Diptera, including Syrphidae, Bombyliidae, Calliphoridae and Muscidae provide pollination services valued in the hundreds of billions of dollars annually. Predatory and parasitoid species in Syrphidae, Tachinidae and Cecidomyiidae deliver natural pest suppression estimated at nearly US$100 billion annually. Overall, this review demonstrate that Diptera play indispensable roles in sustaining ecosystem processes, agricultural productivity and ecological resilience. However, major gaps persist in quantifying their contributions to pollination and pest regulation, particularly in tropical and developing regions. The review concludes that advancing dipteran research through targeted ecological studies, long‐term monitoring and integrative conservation strategies is essential for safeguarding ecosystem functioning and human well‐being.
ABSTRACT Anastrepha grandis (Macquart, 1846) (Diptera: Tephritidae) is one of the primary pests of Cucurbitaceae in the Americas, causing direct damage to agricultural production and being of major quarantine importance. Despite its economic importance, no comprehensive review has yet consolidated information on its geographic distribution, host plants, and management strategies, which limits the identification of knowledge gaps and the development of integrated pest management. Although several studies have addressed the biology, behavior, and management of A. grandis , this information remains scattered and fragmented across the literature, indicating the need for a systematized and critical synthesis. The objective of this review was to synthesize the main scientific findings on A. grandis , with emphasis on its geographic distribution, host plant associations, and population management strategies. This integrative review, conducted using systematized criteria, compiles, organizes, and critically analyzes 53 studies published between 1988 and 2025, revealing a marked increase in scientific output from 2014 onward. The species exhibits a well‐established distribution in South America, with most records concentrated in Brazil, particularly in the Southeast and Central‐West regions. Sixteen host plant species have been reported in the literature, most of which belong to the family Cucurbitaceae. Reported management strategies mainly include the use of baited traps with attractants or other semiochemicals, the application of selective insecticides, quarantine treatments (gamma irradiation and cold treatment), and integrated pest management (IPM) approaches. Nevertheless, significant challenges persist, especially regarding early detection during crop establishment, the delimitation of pest‐free areas, and the projection of potential range expansion under climate change scenarios. Overall, this review fills an important knowledge gap and provides a foundation for more effective and sustainable management strategies, while guiding future research aimed at mitigating the impacts of this pest species on regional and international agriculture.
ABSTRACT Predatory hoverflies show control effects on key agricultural and forestry pests such as aphids and thrips. Moreover, many species provide biological control services on a regional geographical scale driven by their migratory behavior, making them an important taxonomic group for maintaining global ecosystem balance. By reviewing previous studies, this paper identifies 53 species with high potential to serve as effective biological control agents such as Episyrphus balteatus De Geer (Diptera: Syrphidae) and summarizes both large‐scale mass‐rearing‐and‐release technologies and strategies for conservation and utilization of natural populations. Mass‐rearing and release technologies cover the full pipeline from larval rearing to adult release, including environmental control, reproductive optimization, protected‐cultivation deployment, and post‐release monitoring and management, as well as key challenges that should be addressed—including long‐term population storage, long‐distance transportation, and migration of released populations in open fields. For the conservation and utilization of natural populations, this paper focuses on major environmental and agricultural production factors shaping population dynamics and introduces key measures including natural habitat improvement, conservation‐oriented farming practices, and monitoring and evaluation of the biological control functions provided by natural populations. In addition, this paper integrates emerging approaches—such as artificial intelligence and biotechnology—into the application landscape of natural‐enemy insect industries and discusses the prospects of hoverfly‐based biological control.
The objective of this work was to evaluate the effects of sublethal exposure to the insecticides malathion and beta-cyfluthrin on the pheromone perception and emission by the cotton boll weevil [Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae)]. The potential impact of sublethal exposure on this species' population growth was also determined using fertility table parameters. Males and females were exposed to malathion (100 g a.i./L) or beta-cyfluthrin (25 g a.i./L) for 1 min in a glass Petri dish. The response of pesticide-exposed and unexposed insects to their aggregation pheromone (grandlure) was evaluated in a Y-tube olfactometer, and pheromone production was assessed. In order to evaluate the possible reproductive effects, the couples remained isolated for 48 h, and the females were subsequently evaluated until their death. For reproductive assays, four mating-pair treatments were established: (1) both sexes unexposed; (2) exposed males paired with unexposed females; (3) exposed females paired with unexposed males; and (4) both sexes exposed. Insects exposed to both insecticides did not respond to their aggregation pheromone during the first 24 h after exposure, whereas unexposed weevils showed a clear behavioral response. However, insecticide-exposed males did not show reduced pheromone production compared to unexposed males. Sublethal insecticide exposure lowered the net reproductive rate (R 0) and the intrinsic rate of increase (r m) for the cotton boll weevil. These findings suggest that sublethal insecticide exposure may suppress boll weevil population growth while potentially compromising the reliability of pheromone-based monitoring programs in intensively treated cotton fields.
ABSTRACT Selective pressure has driven the evolution of defensive strategies in insects against their natural enemies. These strategies are classified into primary and secondary defenses, which are further subdivided into behavioral, morphological, and chemical categories based on the mechanisms they employ. This review aimed to synthesize insect defense mechanisms from the literature published over three decades (1992–2023), describing and analyzing their efficiency, effects, and relationship with the life history of these organisms. Reports of primary and secondary defenses were obtained for insects across 22 and 20 orders, respectively. Defensive secretions, crypsis, and aposematism were the most reported primary defenses, while toxin release, fighting, and escape were the most frequently reported secondary defenses. Chemical defenses affect insect life history and, although most frequently reported, are not the most widespread across orders. Crypsis and escape, belonging to the morphological and behavioral subdivisions, respectively, are the most common primary and secondary defenses across insect orders. Understanding these mechanisms provides essential insights for biodiversity conservation and sustainable pest management.
ABSTRACT The complex fig‐wasp community, anchored by the obligate mutualism between Ficus and their pollinating wasps, represents a classic example of co‐evolution, critically maintained by species‐specific chemical communication. The chemical communication is mediated by fig syconia releasing specific volatile organic compounds (VOCs), which both pollinating and non‐pollinating wasps detect via their olfactory systems for host recognition. This review systematically outlines the key VOCs emitted by figs and the corresponding olfactory detection mechanisms in fig wasps. The latter covers recent progress in the identification of chemosensory genes, including odorant binding proteins, olfactory receptors, and ionotropic receptors, as well as their functional characterization. While we primarily focus on pollinating fig wasps, we explicitly synthesize available information on non‐pollinating fig wasps. These studies are providing insight into the mechanism of chemical communication and coevolution between figs and fig wasps.
ABSTRACT Macrobial biological control agents, such as parasitoids, play a pivotal role in Integrated Pest Management (IPM), yet their success depends on compatibility with agrochemicals commonly applied in cropping systems. The egg parasitoid Trichogrammatoidea cryptophlebiae Nagaraja, 1979 (Hymenoptera: Trichogrammatidae), widely released in South Africa for tortricid moth management, remains understudied regarding its responses to pesticides used in orchards. This study evaluated the acute and sublethal effects of a representative range of insecticides, fungicides, and biopesticides on multiple life stages of T. cryptophlebiae , applying the International Organisation for Biological Control (IOBC) classification system together with measures of parasitism, sex ratio, and pre‐imaginal development. Adult survival alone was not a reliable indicator of chemical compatibility. The non‐target effects of agrochemicals on T. cryptophlebiae varied across treatments and life stages, influencing adult survival, reproductive output, and developmental success. Several insecticides, particularly pyrethroids and other neuroactive compounds, permitted adult survival but were associated with pronounced reductions in parasitism, consistent with strong sublethal effects on parasitoid performance. In contrast, several fungicides and biopesticides were comparatively benign, having no effect on survival and reproduction. Sex ratios were largely unaffected across treatments. While IOBC mortality thresholds are a useful tool for initial screening of pesticide compatibility with T. cryptophlebiae , these results demonstrate that mortality‐based classifications alone may underestimate incompatibility by failing to capture effects on reproduction and development that are critical to biological control efficacy. By providing the first published assessment of pesticide effects on T. cryptophlebiae , this study offers data relevant to IPM programmes in macadamias and other crops in South Africa and contributes evidence toward refining pesticide‐natural enemy compatibility assessments.
ABSTRACT This special issue comprises papers presented at the 8th International Entomophagous Insects Conference (IEIC8), which took place in Tours, France in 2025. The first applied interest of entomophagous insects is their crucial role in biocontrol, as positive agents limiting other insects known as pests. But, beyond their agronomic value, these insects are fascinating models to investigate physiology, genetics, immunity, behavior, and many other biological traits at different integrative levels. This special issue includes 16 research papers giving examples of topics that were presented and discussed during the conference. It illustrates the diversity of interests around those fascinating insects that are enemies of other insects.
The use of biopesticides in agriculture has grown in recent years, but the effects on non-target species remain insufficiently understood. We assessed both the lethal (e.g., survival) and sublethal (e.g., fecundity and fertility) effects of Prev-Am Plus, a sweet orange essential oil-based biopesticide, on the parasitoid Exorista larvarum (L.) (Diptera: Tachinidae). This species was selected as a model non-target insect due to its dual role as a parasitoid of pest lepidopterans and as a pollinator. Fecundity was expressed as the number of eggs laid, whereas fertility was expressed as the proportion of eggs developing into puparia. The experimental techniques were adapted from internationally recognized protocols used for assessing pesticide toxicity on Apis mellifera L., a reference insect species in environmental risk assessment. Mated E. larvarum females were utilized in the experiments. Both acute contact (a) and oral (b) toxicity were tested by applying a single 1 mu L drop of biopesticide solution onto the fly thorax (a) or offering 10 mu L of biopesticide solution as food to flies (b). Different concentrations (0.25%, 0.5%, 5%, 10%, 20%) of the commercial product were tested. The results showed that both contact and oral exposure to Prev-Am Plus exhibited a dose-response relationship, with mortality increasing with concentration. In contact assays, the estimated LC20 was 3.93%, while the LC50 exceeded the highest tested concentration (20%). In oral assays, the proportion of females consuming the test solution decreased with increasing concentration. Among females that ingested more than 50% of the solution, mortality increased with concentration, with estimated LC20 and LC50 values of 2.5% and 10.8%, respectively. No effects on fecundity or fertility were detected following either exposure route.
Increasing evidence illustrates that insect sex pheromones and host plant volatiles synergistically guide mate localization in insects. The diurnal red moth, Phauda flammans (Walker) (Lepidoptera: Phaudidae), an oligophagous herbivore, exclusively feeds on the genus Ficus spp. (Rosales: Moraceae). We tested the hypothesis that host plant volatiles synergistically enhance male P. flammans responses to female sex pheromones. Behavioral assays in a Y-tube olfactometer showed that odors from either conspecific females or F. concinna branches alone attracted significantly more males than the blank control. When these odor sources were combined, they attracted significantly more males than either alone, with the strongest effect observed when plant volatiles were located upstream of the females, suggesting a potential role of host plant volatiles in modulating female pheromone release. Through electroantennographic and behavioral analyses, we identified the optimal blend, i.e., a mixture of the sex pheromones cis-9-hexadecenal and (Z, Z, Z)-9, 12, 15-octadecatrienal, combined with the plant volatiles (-)-alpha-pinene, beta-myrcene, (Z)-beta-ocimene, and beta-caryophyllene at a ratio of 1:10:100:10:10:1, that elicited strong responses and attracted significantly more males. A field-cage trial revealed that this synergistic blend was significantly more effective than either the sex pheromone or plant volatile alone. Our results demonstrated the synergistic role of host-plant volatiles and sex pheromones in mate location and provided a foundation for developing attractant-based monitoring and management strategies for P. flammans.
