Search Results (35)

Host plant limitation poses a major threat to the endangered specialist butterfly Luehdorfia chinensis Leech, 1893, whose larvae are oligophagous at the species level on Asarum spp., while local populations often appear monophagous, depending on the host plants (A. sieboldii Miq. or A. forbesii Maxim.) available in their habitat. To simulate natural starvation caused by host plant scarcity, third- to fifth-instar larvae were subjected to a three-day deprivation treatment, and the effects on individual fitness traits—including larval development, pupal duration, and adult fecundity—were assessed, along with population dynamics. Starvation significantly prolonged larval development, shortened the pupal stage, reduced female fecundity, and markedly decreased key population parameters, such as the intrinsic rate of increase (r_m) and the net reproductive rate (R₀). Population projections further indicated that repeated starvation stress could reduce population size by more than 83% within two years, potentially intensifying genetic drift, inbreeding depression, and demographic instability, ultimately increasing the risk of extinction. These findings provide direct evidence that host plant limitation drives population decline in L. chinensis, contribute to the broader understanding of global butterfly declines, and underscore the critical importance of conserving and restoring essential habitat resources. Moreover, they highlight the relevance of the resource-based habitat concept for the effective protection of specialist species. Full article

Habitat and climate changes driven by human activities are altering the distribution of organisms globally. In South Korea, recent temperature increases have exceeded twice the global average, and habitats have markedly changed and shrunk due to urban development driven by population growth and economic expansion. Despite its high biodiversity and over 500 years of preservation, Gwangneung Forest in South Korea has experienced habitat alterations due to the urbanization of surrounding rural areas since the 1990s. In this study, we aimed to evaluate how butterfly communities respond to urbanization and climate change using long-term monitoring data (1998–2015) from the conserved Gwangneung Forest. We considered the thermal adaptation types (cold-, warm-, and moderately adapted species), habitat types (forest edge, forest inside, and grassland), diet breadth (monophagous, oligophagous, and polyphagous), and wingspan of butterflies. Linear regression analysis of the abundance trends for each species revealed that cold-adapted species experienced population declines, while warm-adapted species showed increases. Changes in butterfly abundance were associated with both thermal adaptation type and wingspan, with larger, more mobile species showing greater resistance to habitat loss in surrounding areas. To preserve butterfly diversity in Gwangneung Forest and across South Korea, it is crucial to conserve open green habitats—such as gardens, small arable lands, and grasslands—within urban areas, especially considering the impacts of climate change and habitat loss, which disproportionately affect smaller species with limited mobility. Full article

Arecaceae (palms) constitute a highly diversified family of monocots, distributed especially in tropical and subtropical areas, including approximately 2600 species and 180 genera. Palms originated by the end of the Early Cretaceous, with most genus-level cladogenetic events occurring from the Eocene and Oligocene onward. Meligethinae (pollen beetles) are a large subfamily of Nitidulidae (Coleoptera), including just under 700 described species, and some 50 genera. Meligethinae are widespread in the Palearctic, Afrotropical, and Oriental Regions. All meligethine species are associated with flowers or inflorescences of several plant families, both dicots (the great majority) and monocots (around 7%); approximately 80% of known species are thought to be monophagous or strictly oligophagous at the larval stage. The origin of Meligethinae is debated, although combined paleontological, paleogeographical, and molecular evidence suggests placing it somewhere in the Paleotropics around the Eocene–Oligocene boundary, ca. 35–40 Mya. This article reviews the insect–host plant relationships of all known genera and species of Meligethinae associated with Arecaceae, currently including some 40 species and just under ten genera (including a possibly new African one). The role of adults as effective and important pollinators of their host palms (also in terms of provided ecosystem services) has been demonstrated in some common palm species. All Meligethinae living on palms show rather close phylogenetic relationships with one another and with the mainly Eastern Palearctic genus Meligethes Stephens, 1830 and related genera (associated with dicots of the families Rosaceae, Brassicaceae, or Cleomaceae). Molecular data suggests that the palm-associated Paleotropical genus Meligethinus Grouvelle, 1906 constitutes the sister-group of Meligethes and allied genera. Some hypotheses are presented on the evolution of Meligethinae associated with palms and their probably rather recent (early Miocene–Pleistocene) radiation on their host plants. Meligethinae likely radiated on palms long after the diversification of their hosts, and their recent evolution was driven by repeated radiation on pre-existing and diverse palm taxa, rather than ancient host associations and coevolution. Finally, this article also briefly summarized the relationships that other unrelated groups of Nitidulidae have established with palms around the world. Full article

The ladybird beetle, Henosepilachna vigintioctopunctata, is an oligophagous pest with significant economic impact. This pest causes considerable economic damage on numerous Solanaceae crops. Neuropeptides, along with their designated receptors, play a pivotal role in regulating diverse biological processes in insects, presenting a promising avenue for innovative pest management strategies. Herein, the transcriptome of the central nervous system (CNS) of H. vigintioctopunctata was sequenced. Overall, our analysis identified 58 neuropeptide precursor genes, from which 98 diverse mature peptides were predicted. Furthermore, 31 neuropeptide receptor genes belonging to three distinct classes were discovered, along with predictions for their potential ligands. Moreover, the expression patterns of these 58 neuropeptide genes across larval brain tissue, ventral nerve cord, and gut were evaluated using quantitative real-time PCR. Collectively, these findings will significantly contribute to future research focused on understanding the physiological functions and pharmacological characteristics of neuropeptides and their receptors in H. vigintioctopunctata. Ultimately, these insights may facilitate the development of targeted neuropeptide-based solutions for managing this pest affecting solanaceous plants. Full article

Two of the most studied species, monophage Trioza magnisetoza Loginova, 1964 (Hemiptera, Triozidae) and narrow oligophage Altica ballasogloi (Jakobson, 1892) (Coleoptera, Chrysomelidae), are offered for biological control of Russian olive (Elaeagnus angustifolia) in the USA. The data obtained over 15 years and presented in this publication on biological and ecological features, host plants, damage to the host plants, and suggested approaches for establishing new populations of both species are sufficient for their use in biological control in North America. Currently, 72 species of insects from 58 genera, 33 families, and six orders are known in Central Asia as pests of Russian olive. The most numerous are insects from the order Coleoptera (36 species, 29 genera, 10 families), Homoptera (14 species, eight genera, six families), and Lepidoptera (13 species from 12 genera, 10 families). Twenty-four species from this list, including eight species of monophages and 16 species of oligophages, are the most suitable for biological control of Russian olive. In addition, six other species of insect pests with unexplored food specialization but associated with Russian olive might also be used. Full article

The evolution of phytophagous insects has resulted in the development of feeding specializations that are unique to this group. The majority of current research on insect palatability has concentrated on aspects of ecology and biology, with relatively little attention paid to the role of insect gut symbiotic bacteria. Symbiont bacteria have a close relationship with their insect hosts and perform a range of functions. This research aimed to investigate the relationship between insect host plant range and gut symbiotic bacteria. A synthesis of the extant literature on the intestinal commensal bacteria of monophagous, oligophagous, and polyphagous tephritids revealed no evidence of a positive correlation between the plant host range and the diversity of larval intestinal microbial species. The gut symbionts of same species were observed to exhibit discrepancies between different literature sources, which were attributed to variations in multiple environmental factors. However, following beta diversity analysis, monophagy demonstrated the lowest level of variation in intestinal commensal bacteria, while polyphagous tephritids exhibited the greatest variation in intestinal commensal bacteria community variation. In light of these findings, this study proposes the hypothesis that exclusive or closely related plant hosts provide monophagy and oligophagy with a stable core colony over long evolutionary periods. The core flora is closely associated with host adaptations in monophagous and oligophagous tephritids, including nutritional and detoxification functions. This is in contrast to polyphagy, whose dominant colony varies in different environments. Our hypothesis requires further refinement of the data on the gut commensal bacteria of monophagy and oligophagy as the number of species and samples is currently limited. Full article

Dioryctria abietella Denis Schiffermuller (Lepidoptera: Pyralidae) is an oligophagous pest that mainly damages Pinaceae plants. Here, we investigated the effects of the Bacillus thuringiensis 2913 strain (Bt 2913), which carries the Cry1Ac, Cry2Ab, and Vip3Aa genes, on the D. abietella midgut transcriptome at 6, 12, and 24 h after infection. In total, 7497 differentially expressed genes (DEGs) were identified from the midgut transcriptome of D. abietella larvae infected with Bt 2913. Among these DEGs, we identified genes possibly involved in Bt 2913-induced perforation of the larval midgut. For example, the DEGs included 67 genes encoding midgut proteases involved in Cry/Vip toxin activation, 74 genes encoding potential receptor proteins that bind to insecticidal proteins, and 19 genes encoding receptor NADH dehydrogenases that may bind to Cry1Ac. Among the three transcriptomes, 88 genes related to metabolic detoxification and 98 genes related to immune defense against Bt 2913 infection were identified. Interestingly, 145 genes related to the 60S ribosomal protein were among the DEGs identified in the three transcriptomes. Furthermore, we performed bioinformatic analysis of zonadhesin, GST, CYP450, and CarE in the D. abietella midgut to determine their possible associations with Bt 2913. On the basis of the results of this analysis, we speculated that trypsin and other serine proteases in the D. abietella larval midgut began to activate Cry/Vip prototoxin at 6 h to 12 h after Bt 2913 ingestion. At 12 h after Bt 2913 ingestion, chymotrypsin was potentially involved in degrading the active core fragment of Vip3Aa toxin, and the detoxification enzymes in the larvae contributed to the metabolic detoxification of the Bt toxin. The ABC transporter and several other receptor-protein-related genes were also downregulated to increase resistance to Bt 2913. However, the upregulation of 60S ribosomal protein and heat shock protein expression weakened the resistance of larvae to Bt 2913, thereby enhancing the expression of NADH dehydrogenase and other receptor proteins that are highly expressed in the larval midgut and bind to activating toxins, including Cry1Ac. At 24 h after Bt 2913 ingestion, many activated toxins were bound to receptor proteins such as APN in the larval midgut, resulting in membrane perforation. Here, we clarified the mechanism of Bt 2913 infection in D. abietella larvae, as well as the larval immune defense response to Bt 2913, which provides a theoretical basis for the subsequent control of D. abietella using B. thuringiensis. Full article

Dioryctria sylvestrella (Lepidoptera: Pyralidae) is a destructive borer pest on Korean pine (Pinus koraiensis) indigenous to northeastern China. The antennal sensilla of D. sylvestrella were examined by scanning electron microscopy to understand the behavioral ecology of this insect pest. Both the male and female antennae are filiform, and each consists of a scape, a pedicel, and a flagellum. D. sylvestrella is characterized by sexual dimorphism. Only the male antennae present two deeply grooved thumblike protuberances on the crest surfaces of their fourth and fifth flagellomeres, respectively. These structures have never been reported for any other Pyralidae. Eight different types of sensilla with unique bioecological functions were detected on the antennae of both sexes. There may be structure–location–function relationships for these sensilla, and most of them are involved in communication between the insect and the host plant, mate detection, and oviposition site selection. Full article

The temporal variation in a community of nocturnal and diurnal Lepidoptera was studied in a Mediterranean mid-mountain area of the SW Iberian Peninsula between 2017 and 2019. Monthly samplings that allowed for the identification of 3528 specimens, belonging to 373 species from 40 different families, also provided data on the temporal and seasonal variation in richness and the abundance (dominated by Geometridae and Noctuidae), diet type (mainly oligophagous), voltinism (mostly univoltine) and biogeography of the community, primarily Mediterranean in scope. Richness, abundance and diversity were also found to be highly positively correlated with temperature and solar radiation, and less negatively correlated with precipitation and humidity. Canonical correspondence analyses (CCAs) also indicate that temperature and radiation are the climatic variables with the greatest influence on species occurrence over the different months of the year. The CCAs gave a cumulative variance value of 84.79% when using the monthly mean values of temperature, solar radiation and minimum relative humidity, and 86.4% if only monovoltine species were considered. Guidelines to maintain diversity in the environment of the study area are provided. It is possible that the area may function as a refuge area for Lepidoptera in the face of climate change and deforestation that are occurring in the geographical environment. Full article

Crop rotation is an important strategy for pest reduction. For mono-, or oligophagous pests that overwinter at a previously infested site, crop rotation means that the pests must find new host crop sites in the following year, and it is more efficient if a pest-specific distance is applied. Here, we report the development of a GIS-based tool for efficient cultivation planning using the example of the pest complex pea moth (Cydia nigricana) and grain and green peas (Pisum sativum). Monitoring data for four consecutive years (2016–2019) from 513 sites were used. Infestation of pea seeds and the distance to the previous year’s pea sites were recorded. An adjustable Python script was developed by means of infestation–distance–correlation as a pest and crop-specific minimum migration distance (MD). The output of the tool is a risk map as decision support for cultivation planning. It shows different risk buffers with distances from 1261 m to 1825 m, depending on the cultivation type. The web tool is easily adjustable to other pests and crops anywhere in the world. The tool helps to prevent damages caused by agricultural, mono-, or oligophagous insect pests and consequently reduces pesticide applications for the benefit of the environment and biodiversity. Full article

The Camellia weevil, Curculio chinensis (Chevrolat, 1978), is a dominant oligophagous pest that bores into the fruit of oil-tea Camellia. Genetic differentiation among populations in various hosts can easily occur, which hinders research on pest management. In this study, the genetic structure, genetic diversity, and phylogenetic structure of local C. chinensis populations were examined using 147 individuals (from 6 localities in Jiangxi), based on 2 mitochondrial COI markers. Results indicated that the C. chinensis population in Jiangxi exhibits a high haplotype diversity, especially for the populations from Cam. meiocarpa plantations. Structural differentiation was observed between Haplogroup 1 (73 individuals from Ganzhou, Jian, and Pingxiang) in the monoculture plantations of Cam. meiocarpa and Haplogroup 2 (75 individuals from Pingxiang and Jiujiang) in Cam. oleifera. Two haplogroups have recently undergone a demographic expansion, and Haplogroup 1 has shown a higher number of effective migrants than Haplogroup 2. This suggests that C. chinensis has been spreading from Cam. meiocarpa plantations to other oil-tea Camellia, such as Cam. oleifera. The increased cultivation of oil-tea Camellia in Jiangxi has contributed to a unique genetic structure within the C. chinensis population. This has, in turn, expanded the distribution of C. chinensis and increased migration between populations. Full article

This review describes global rice stemborer assemblages based on published species distributions, apparent host preferences, and reported shifts in assemblage composition in response to environmental factors. At least 56 moth (Lepidoptera: Crambidae, Pyralidae, Noctuidae) and fly (Diptera: Diopsidae, Chloropidae) species have been associated with rice; however, only 21 species are of potential, large-scale economic importance with a further 2 species of localized concern; most of the remaining species’ associations with rice are based on dubious records without economic impacts on rice production. A list of stemborer–host associations indicates that rice stemborers are largely oligophagous on grasses (Poaceae), but a few species are polyphagous (also attacking Cyperaceae, Typhaceae, and some Eudicotyledon plants). Total stemborer abundance is determined by rice cropping patterns and management. Assemblage species richness is determined by geographical location, surrounding habitat (particularly as regards secondary and occasional species), and season. Evidence suggests that stemborer assemblage structure is largely determined through conditional interspecific competition. Regional assemblages typically include a single dominant lepidopteran species (primary species) that is largely restricted to rice and for which the climate is optimal; one or more secondary species that vary based on the age of rice attacked, rice anatomy, and the proximity to other habitats (including other crops); and occasional species that probably spill over from adjacent grasslands. The co-occurrence of lepidopteran with dipteran rice stemborers requires further research attention. Full article

The present study evaluated the host plant effect on life type characteristics of three important spider mite pest species, Tetranychus urticae Koch, Eutetranychus orientalis (Klein), and E. palmatus Attiah (Acari: Prostigmata: Tetranychidae), based on both field and laboratory observations. The polyphagous species, T. urticae with complicated web (CW-u) life type, occupying unstable habitats, showed variations in the sites for quiescence (SQ), sites for oviposition (SO), sites for defecation (SD), and webbing density (WD) on different annual/perennial host plants. The SQ, SO, and SD of T. urticae were observed either on the leaf, web threads, or trichomes. Tetranychus urticae constructed the lowest WD on tomato plants and the highest WD on maize/mulberry plants. Two spider mite species of the genus Eutetranychus Banks, the polyphagous E. orientalis and the oligophagous E. palmatus, inhabit stable host plants, depicted in the little web (LW-j) life types with persistency in all characteristics on different plants. It is concluded that polyphagous spider mites have restricted their life types, showing their high adaptability to utilize the resources of different host plants for survival with slight variation in some important life type characteristics. Full article

Curculio elephas is an oligophagous insect, attacking fruits of chestnut (Castanea spp.) and oak (Quercus spp.). It is considered one of the most important pests of European chestnut (Castanea sativa) in Europe and it occurs in a continuous range throughout Greece. The aim of this study was to identify the potential volatile organic compounds (VOCs) from chestnut reproductive plant tissues (catkin, nut, and bur) acting as attractants for C. elephas adults to be used for the development of a monitoring system integrating pest management tools. VOCs were sampled in situ during spring and autumn of 2021 and 2022 in different areas of Greece. For the collection and identification of VOCs, the dynamic-headspace technique combined with gas chromatography–mass spectrometry (GC–MS), was employed. In total, 122 compounds from these tissues were detected, with most of them being terpenes (>80%). Further analysis showed that chestnut trees release different VOCs depending on their developmental stage. Antennae of both male and female chestnut weevil adults responded to terpenes, green leaf volatiles, and methyl salicylate. Identification of semiochemicals for manipulating weevils’ behavior will contribute to the development of efficient monitoring tools for the detection and management of this pest. Full article

The aim of the study was to determine the influence of differentiated landscape management on the distribution and abundance of butterfly species. The question was raised with regard to which land use type benefited butterflies, and which affected them, that is: under which management type does biodiversity increase, and under which is it depleted? The spatial and abundance distributions of the examined butterfly species diverged considerably. The observed differences between the abundance distributions may be due to diverse conditions in the small-scale environments or specific food preferences of individual species. The diversified management of the “Krzywda” landscape fosters the abundance of mesophilic and ubiquitous butterfly species, whereas xerotermophilic and hygrophilous species are not fostered. The transects established on the fallow land with harvested biomass as well as that with unharvested biomass and in the forest ecotone showed that the fallows were characterized by the highest abundance of butterflies, and the greatest number of plant species was recorded there. Mown fallow lands with not harvested biomass as well as forested areas fostered polyphagous and monophagous butterfly species. Oligophagous butterfly species were fostered by mown fallow lands with not harvested biomass. Unmown meadows, the ecotone marshland and fallow, as well as unmown fallow lands did not foster butterfly abundance. This most likely means that land management can influence the food base of butterflies, and consequently, their abundance. The stage of succession as well as the homogeneity of the area in terms of vegetation had the strongest filtering effect on the occurrence and distribution of butterflies among the analyzed variables. The number of species as well as their abundance was higher on transects classified as young successional stages on which successional processes were artificially inhibited by mowing and biomass removal. Advanced environmental engineering enables humans to influence species composition in a given ecosystem to achieve a desired result. There is no doubt that human activity will be successful when the needs of individual species in a given environment are accurately understood. Full article