Parasitoids are a megadiverse group, and some of the most speciose parasitoid communities are associated with leaf miners. For koinobiont endoparasitoids, host discrimination is important, but parasitoids can hardly contact host individuals before laying eggs. However, we know little about the extent to which parasitoids specialize in different leafminer species coexisting on the same host plant. This study compared the community structures of ichneumonoid koinobiont endoparasitoids among leaf miners of Gracillariidae (Lepidoptera) on three fabaceous plant species, Pueraria lobata, Lespedeza bicolor and Wisteria floribunda, in Japan. Each of the three fabaceous species is utilized by three to four non-congeneric gracillariid species. We collected 11 parasitoid species from nine gracillariid leafminer species belonging to six genera. None of the collected parasitoid species emerged from all the gracillariid species that shared a host-plant species, nor from all the congeneric gracillariid species on different host-plant species. Although significant community structures were not detected, the "parasitoid-host genus" network exhibited higher network-level specialization (H2 ' = 0.7701) than the "parasitoid-plant species" network (H2 ' = 0.6511). Cryptic divergence (>5%) was also detected among individuals in Centistidea mogrus (Papp) (Hymenoptera: Braconidae), which were divided into two monophyletic clades; one showed wider association with gracillariids and plants, whereas the other specialized on a single gracillariid taxon on a specific host plant. Our results indicate that the majority of koinobiont endoparasitoids utilizing gracillariid leaf miners exhibit species-specific interactions with their host, even when multiple gracillariid species are associated with the same host plant species.
Abstract Insects impact many aspects of human life, shaping ecosystems, driving economies, and serving as muses for the arts and music. They pollinate crops and gardens, and are food sources for many animals, including humans. They can vector pathogens that cause disease and can be pests in urban and rural settings. Given current rates of decline in insects, vital positive human–insect interactions may be disrupted, and negative interactions exacerbated as insect abundance and biodiversity decrease. Here, we review some of the ways that insects impact human quality of life and how their decline may impact humanity.
Introduced phytophagous insects that use native host plants tend to recruit native parasitoids either from among those attacking native insect hosts closely related to the introduced insect or from among those attacking other insects feeding on the adopted host plant of the introduced herbivore. The introduced North American cynipid gall wasp Liposthenes glechomae Linnaeus 1758 (Hymenoptera: Cynipidae: Aulacideini) is peculiar in that neither the wasp nor its host plant, the ground ivy Glechoma hederacea, has congeners in North America. Consequently, there would appear to be few opportunities for parasite recruitment. We studied the origins of the parasitoid wasp community of L. glechomae in North America by collecting in Iowa and Pennsylvania, dissecting and rearing insects from galls and sequencing larvae and adults. We found 3 parasitoid species. Two of these, Phaenocytus glechomae F & ouml;rster, 1841 (Hymenoptera: Pteromalidae) and Torymus cingulatus Nees von Esenbeck, 1834 (Hymenoptera: Torymidae), were not new recruits but rather parasitoids of L. glechomae in its native range that have followed their host gall wasp and its host plant to North America. Of the 3 parasitoid species recorded, only 1 is native to North America, Torymus advenus Osten-Sacken, 1870 (Hymenoptera: Torymidae), a generalist that also attacks many different cynipid gall wasps and gall midges associated with a variety of Nearctic plants. After more than 3 centuries in North America, L. glechomae has recruited just 1 new parasitoid in the studied region.
Over the past decade, leafhoppers (Hemiptera: Cicadellidae) have gained increasing attention as agricultural pests and vectors of phytoplasma diseases in Qu & eacute;bec. To determine whether their pest status has changed over time, we analyzed historical and contemporary records spanning 1868 to 2025, focusing on 2 ecological groups: species that overwinter in Qu & eacute;bec (local species) and species that migrate annually (migratory species). Our analysis revealed that local leafhoppers have been recognized as pests since at least 1886, although they were generally regarded as having secondary economic importance. In contrast, migratory species, first reported in 1908, have been more frequently associated with economically significant crop damage. Among these, Empoasca fabae (Harris) and Macrosteles quadrilineatus (Forbes) were associated with 10 agricultural crops and accounted for 11% to 88% of adult specimens in reported crop assemblages. Local species were primarily associated with grapevine and apple production, respectively. We further found that first annual field reports from 1997 to 2025 are occurring progressively earlier in crops dominated by migratory species, such as potato and strawberry. These results suggest that recent changes in leafhopper pest status in Qu & eacute;bec are being driven primarily by migratory species and that migratory leafhoppers have long been an important component of Qu & eacute;bec agroecosystems, but their growing visibility and earlier seasonal report are increasing their perceived economic importance. The historical framework developed here provides a valuable approach for tracking changes in pest status through time and offers a useful tool for understanding how climate change may reshape the importance of agricultural pests in the future.
Ptinid beetles (Ptinidae Latreille, 1802) are essential components of forest and terrestrial trophic networks, exhibiting highly diverse ecologies. While many species are vital as decomposers of organic matter, others are widely recognized as significant pests of stored products and cultural heritage. Understanding the evolutionary timeline of this ecologically and economically important lineage is crucial, yet its fossil record predating the late Eocene remains understudied. Herein, we examined a well-preserved ptinid inclusion from the lowermost Eocene Oise amber (Sparnacian, similar to 53 Ma, France) using synchrotron-based phase-contrast X-ray microtomography. We describe dagger Imaginedraconium daemon gen. et sp. nov., which represents the first fossil record of the "Cryptoramorphini" group and the second earliest documented occurrence of the subfamily Dorcatominae Thomson, 1859. This new taxon provides a rare glimpse into a subfamily whose early history is otherwise almost exclusively documented from the later Baltic amber (similar to 35 Ma). This discovery documents the presence of a dorcatomine beetle in the warm, humid forests of the Oise amber deposit, although its ecology remains uncertain, and offers a valuable temporal calibration point for future phylogenetic and molecular dating analyses of the family.
