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Koinobionts are parasitoids that allow their hosts to grow after infection, and they finally kill their host individuals at parasitoid-specific host stages. Since fatal accidents of host organisms directly result in the deaths of parasitizing koinobionts, a longer parasitization period in vulnerable hosts is likely to increase the mortality of the koinobionts. However, for hosts inhabiting concealed environments in their later developmental stages, koinobionts should begin parasitization in early-stage hosts to make use of the grown hosts. A koinobiont parasitoid, Aneurobracon philippinensis (Muesebeck), mainly uses a leaf-mining moth, Acrocercops transecta Meyrick (Lepidoptera: Gracillariidae) as a host. Due to the three-dimensional structure of the mines constructed by later instars of A. transecta, females of A. philippinensis seldomly oviposit into later instar hosts, whereas feeding on final instar hosts is essential for A. philippinensis larvae. This implies that oviposition targets in the wild are shifted to early instars, though the final instar is the ideal target to shorten the parasitization period. The dissection of wild host larvae demonstrated that no eggs were observed in the final instar, supporting the above expectation. Laboratory parasitization experiments revealed that A. philippinensis eggs hatched approximately 80 h after oviposition, and hatched larvae stayed in the first instar until the host larvae completed making cocoons. These results suggest that the first-instar period of the parasitoid larvae functions as an adjusting period to synchronize the parasitoid and host developmental stages and that koinobiosis plays an important role in utilizing the final instar of A. transecta as a resource.

Asian species of the genus Vespina Davis, 1972 (Lepidoptera, Incurvariidae) are mainly reviewed. Vespina meridiana Hirowatari & Yagi sp. nov. from the Ryukyu Islands, Japan, and Vespina sichuana Hirowatari, Huang & Wang sp. nov. from Sichuan, China, are described. The previously known Vespina species are associated with plants from the Fagaceae family on the western coast of the USA and East Asia and with Sapindaceae (Aceraceae) in eastern Europe. The two new species described here are associated with Fagaceae and Myricaceae, respectively, in warm temperate areas in Asia. Vespina nielseni Kozlov, 1987, which was only known from East Asia, is newly recorded from South China. A checklist for the genus is provided herein. Morphological information of the immature stages of the two new species is partially provided. The absence or reduction of a female frenulum and presence of approximately 20 thin pseudofrenular bristles, the dorsoventrally flattened pupa, and the minute tergal spines scattered on abdominal segments 3–8 are considered as possible autapomorphies of Vespina.

Insect galls are unique organs that provide shelter and nutrients to the gall-inducing insects. Although insect galls are fascinating structures for their unique shapes and functions, the process by which gall-inducing insects induce such complex structures is not well understood. Here, we performed RNA-sequencing-based comparative transcriptomic analysis of the early developmental stage of horned gall to elucidate the early gall-inducing process carried out by the aphid, Schlechtendalia chinensis, in the Chinese sumac, Rhus javanica. There was no clear similarity in the global gene expression profiles between the gall tissue and other tissues, and the expression profiles of various biological categories such as phytohormone metabolism and signaling, stress-response pathways, secondary metabolic pathways, photosynthetic reaction, and floral organ development were dramatically altered. Particularly, master transcription factors that regulate meristem, flower, and fruit development, and biotic and abiotic stress-responsive genes were highly upregulated, whereas the expression of genes related to photosynthesis strongly decreased in the early stage of the gall development. In addition, we found that the expression of class-1 KNOX genes, whose ectopic overexpression is known to lead to the formation of de novo meristematic structures in leaf, was increased in the early development stage of gall tissue. These results strengthen the hypothesis that gall-inducing insects convert source tissues into fruit-like sink tissues by regulating the gene expression of host plants and demonstrate that such manipulation begins from the initial process of gall induction.

Galls are plant structures generated by gall-inducing organisms including insects, nematodes, fungi, bacteria and viruses. Those made by insects generally consist of inner callus-like cells surrounded by lignified hard cells, supplying both nutrients and protection to the gall insects living inside. This indicates that gall insects hijack developmental processes in host plants to generate tissues for their own use. Although galls are morphologically diverse, the molecular mechanism for their development remains poorly understood. To identify genes involved in gall development, we performed RNA-sequencing based transcriptome analysis for leaf galls. We examined the young and mature galls of Glochidion obovatum (Phyllanthaceae), induced by the micromoth Caloptilia cecidophora (Lepidoptera: Gracillariidae), the leaf gall from Eurya japonica (Pentaphylacaceae) induced by Borboryctis euryae (Lepidoptera: Gracillariidae), and the strawberry-shaped leaf gall from Artemisia montana (Asteraceae) induced by gall midge Rhopalomyia yomogicola (Oligotrophini: Cecidomyiidae). Gene ontology (GO) analyses suggested that genes related to developmental processes are up-regulated, whereas ones related to photosynthesis are down-regulated in these three galls. Comparison of transcripts in these three galls together with the gall on leaves of Rhus javanica (Anacardiaceae), induced by the aphid Schlechtendalia chinensis (Hemiptera: Aphidoidea), suggested 38 genes commonly up-regulated in galls from different plant species. GO analysis showed that peptide biosynthesis and metabolism are commonly involved in the four different galls. Our results suggest that gall development involves common processes across gall inducers and plant taxa, providing an initial step towards understanding how they manipulate host plant developmental systems.

In insects, the gall-inducing life-style has evolved independently many times. Several evolutionary pathways leading to this lifestyle have been proposed. While there is compelling evidence supporting surface-feeders and stem-borers as ancestral states of insect gall-inducers, an evolutionary pathway from leaf-miners remains hypothetical. Here we explored this question by comparing the developmental processes of two micromoths, a gall-inducer Caloptilia cecidophora (Lep., Gracillariidae), and its non-gall-inducing relative C. ryukyuensis. Like other Caloptilia, the first and second instars of C. cecidophora are leaf-miners and the gall is initiated inside the leaf mine by the third instar, thus suggesting leaf-mining as an ancestral, plesiomorphic state in this case. This is the first example of an insect species switching from leaf-mining to gall-inducing during larval development. The first two leaf-mining instars of C. cecidophora exhibit an absence of growth and a reduced time duration compared to C. ryukyuensis. The shortening of the duration of leaf-mining stages is apparently compensated in C. cecidophora by a larger egg size than C. ryukyuensis, and an additional larval instar during the gall phase.

This paper provides new taxonomic and biological data on a complex of gracillariid moths in the endemic genus Philodoria Walsingham, 1907 that are associated with Myrsine (Primulaceae) in the Hawaiian Islands, United States. Two new species, Philodoria kauaulaensis Kobayashi, Johns & Kawahara, sp. n. (host: Myrsine lanaiensis, M. lessertiana, and M. sandwicensis) and P. kolea Kobayashi, Johns & Kawahara, sp. n. (host: M. lessertiana) are described. Biological data are provided for two previously described species that also feed on Myrsine: P. auromagnifica Walsingham, 1907 and P. succedanea Walsingham, 1907. For the first time we detail and illustrate genital structures, immature stages, biology, and host plants of P. auromagnifica and P. succedanea. Philodoria kolea, P. auromagnifica, and P. succedanea occur in sympatry on the island of Hawaii (Big Island), but each species differs in behavioral characters: P. kolea utilizes leaves of seedlings and forms a serpentine mine, whereas the latter two utilize leaves of larger plants, and form linear or serpentine to blotch mines. More broadly, leaf mine forms and diagnostic characteristics of the Myrsine-feeding species complex of Philodoria (as currently known) are reviewed and illustrated.

This paper provides new taxonomic and biological data on a complex of gracillariid moths in the endemic genus Philodoria Walsingham, 1907 that are associated with Myrsine (Primulaceae) in the Hawaiian Islands, United States. Two new species, Philodoriakauaulaensis Kobayashi, Johns & Kawahara, sp. n. (host: Myrsinelanaiensis, M.lessertiana, and M.sandwicensis) and P.kolea Kobayashi, Johns & Kawahara, sp. n. (host: M.lessertiana) are described. Biological data are provided for two previously described species that also feed on Myrsine: P.auromagnifica Walsingham, 1907 and P.succedanea Walsingham, 1907. For the first time we detail and illustrate genital structures, immature stages, biology, and host plants of P.auromagnifica and P.succedanea. Philodoriakolea, P.auromagnifica, and P.succedanea occur in sympatry on the island of Hawaii (Big Island), but each species differs in behavioral characters: P.kolea utilizes leaves of seedlings and forms a serpentine mine, whereas the latter two utilize leaves of larger plants, and form linear or serpentine to blotch mines. More broadly, leaf mine forms and diagnostic characteristics of the Myrsine-feeding species complex of Philodoria (as currently known) are reviewed and illustrated.

The use of physical barriers is a common defensive strategy in small-sized endophagous arthropods, but this feeding mode often results in tracks being left on host organisms, thus increasing predation risk. Mechanisms of escape from tracking predators are thus particularly important for endophagous arthropods. Leaf miners are herbivorous insects that inhabit the interiors of leaves and produce various forms of tracks on their host plants. Such tracks are called “mines,” and parasitoid wasps, which are the primary enemy of leaf miners, use mines as cues to find host larvae. In the present study, we use the leaf-mining moth Acrocercops transecta (Insecta: Lepidoptera: Gracillariidae), which changes mine forms during larval growth, and its primary parasitoid Aneurobracon philippinensis (Hymenoptera: Braconidae). Larvae of A. transecta make narrow linear mines in the first and second instars, the third instars expand the mines to flat blotch mines, and the fourth and fifth instars construct three-dimensional tentiform blotch mines. A laboratory parasitization experiment showed that successful oviposition rates were significantly lower on tentiform blotch mines than on other mine types. In contrast, all fifth instars that were transplanted into flat blotch mines were oviposited, suggesting that older instars did not deter ovipositing parasitoids and that the lower rates of successful oviposition on tentiform blotch mines were attributable to refuges inside such mines provided by their three-dimensional structure. Field data demonstrated a plateau in parasitism rates in fourth instar larvae, confirming the results of the laboratory experiment. These results indicate that different mine forms affect the viability of endophagous larvae.

International audience; During an ongoing DNA-barcoding campaign of the leaf-mining moths that feed on woody plants in Northeast Asia, four lineages of the genus Phyllocnistis (Gracillariidae, Phyllocnistinae) were discovered on dogwood (Cornus spp): P. cornella Ermolaev, 1987 on C. controversa Hemsl. (Japan: Hokkaido) and three new species - one feeding on C. controversa, C. florida L. and C. macrophylla Wall. in Japan (Honshu, Shikoku, Kyushu), a second species on C. macrophylla in China (Yunnan) and a third on Siberian dogwood Cornus alba L. in Russia (Siberia). All these species showed differences in morphology, in the barcode region of the cytochrome c oxidase I gene and in two nuclear genes (histone H3 and 28S ribosomal RNA). No correlation was found between the deep mitochondrial splits observed and the Wolbachia infection pattern. Based on both morphological and molecular evidence, the three recently discovered lineages are described here as new species: P. indistincta Kobayashi & Triberti, sp. n. (Japan), P. saepta Kirichenko, Ohshima & Huang, sp. n. (China) and P. verae Kirichenko, Triberti & Lopez-Vaamonde, sp. n. (Russia). In addition, the authors re-describe the adult morphology of P. cornella, provide the first record of this species from Japan and highlight the diagnostic characters that allow these Cornus-feeding Phyllocnistis species to be distinguished.

International audience; Leaves represent the main resource for herbivorous insects and their performances are mainly a function of leaf nutritional quality. Two feeding strategies are known to optimize the exploitation of leaf resources: leaf-miners that selectively feed on tissues of high nutritional quality and gall-inducers that induce the development of a new tissue showing an enhanced nutritional value. Some leaf-miners are known to also manipulate their nutritional environment , but do not affect plant development. Cases of callus proliferation in leaf-mines have been reported, however, the direct role of the insect in the formation of additional plant cells and the nutritional function of this tissue have never been established. Using an experimental approach, we show that leaf-mining larvae of micromoth, Borboryctis euryae (Lepidop-tera: Gracillariidae), that grow on Eurya japonica (Pentaphylacaceae), actively induce callus proliferation within their leaf-mine at the fourth instar. We experimentally demonstrated that, at this developmental stage, the larva feeds exclusively on this newly formed tissue and feeding of the tissue is essential for completing larval stage. Phenological census revealed considerable expansion and variation of fourth instar duration caused by the continuous production of callus. We propose here the "cornucopia" hypothesis which states that the newly produced callus induced by the leaf-mining larvae provides virtually unending nourishment, which in turn allows flexible larval development time. This represents the first example of a leaf-miner manipulating plant development to its benefit, like a gall-inducer. We propose to name this life style "mine-galler".

During an ongoing DNA-barcoding campaign of the leaf-mining moths that feed on woody plants in Northeast Asia, four lineages of the genus Phyllocnistis (Gracillariidae, Phyllocnistinae) were discovered on dogwood (Cornus spp): P. cornella Ermolaev, 1987 on C. controversa Hemsl. (Japan: Hokkaido) and three new species – one feeding on C. controversa, C. florida L. and C. macrophylla Wall. in Japan (Honshu, Shikoku, Kyushu), a second species on C. macrophylla in China (Yunnan) and a third on Siberian dogwood Cornus alba L. in Russia (Siberia). All these species showed differences in morphology, in the barcode region of the cytochrome c oxidase I gene and in two nuclear genes (histone H3 and 28S ribosomal RNA). No correlation was found between the deep mitochondrial splits observed and the Wolbachia infection pattern. Based on both morphological and molecular evidence, the three recently discovered lineages are described here as new species: P. indistincta Kobayashi & Triberti, sp. n. (Japan), P. saepta Kirichenko, Ohshima & Huang, sp. n. (China) and P. verae Kirichenko, Triberti & Lopez-Vaamonde, sp. n. (Russia). In addition, the authors re-describe the adult morphology of P. cornella, provide the first record of this species from Japan and highlight the diagnostic characters that allow these Cornus-feeding Phyllocnistis species to be distinguished.

Differences in host-plant species may affect the structure of parasitoid communities of phytophagous insects. Phytophagous insect species often consist of host races, and comparisons between host races enable us to infer the effects of host-plant differences on parasitoid communities. Here, we compare the parasitoid fauna of two host races of the leaf-mining moth Acrocercops transecta, which are associated with either Juglandaceae or Lyonia ovalifolia (Ericaceae). Field collection and subsequent laboratory rearing revealed a significantly higher parasitization ratio in the Juglandaceae race than in the Lyonia race. In the Juglandaceae race the majority of parasitoids were Braconidae, whereas in the Lyonia race the majority were Eulophidae. Furthermore, even within the same host race the most abundant parasitoid species differed between populations with different host associations. Hence, the present results strongly indicate that different host-plant taxa affect the structure of parasitoid communities eve...

Genetic differentiation in ecological traits plays an important role in the reproductive isolation of phytophagous insects. The present study aims to elucidate the genetic changes involved during the process of host shifts, by combining analyses for (1) host adaptations, (2) pre- and postmating isolation, and (3) phylogeney among populations, using a leaf-mining moth, Acrocercops transecta. This species is associated with Juglans ailanthifolia and Lyonia ovalifolia. Transplantation of the larvae demonstrated that the Juglans-associated population completely failed to survive on Lyonia, whereas the Lyonia-associated population survived on Juglans as well as on Lyonia. Females of respective host-associated populations oviposited on their natal host plant only. An mtDNA-based phylogeny clearly separated the Lyonia-associated population from the Juglandaceae-associated population, and indicated that the Lyonia-associated population once evolved from the Juglandaceae-associated population. These results indicate that the processes of host shifting from juglandaceous species to Lyonia involved genetic changes both in larval ability to use host plants and in host preference of females. The derived Lyonia-associated population has retained the potential to assimilate the ancestral host, Juglandaceae. Mating between the two host-associated populations was successful for both directions of crossing, and there were no significant differences in egg hatchability between hybrids and control crosses. No adults emerged when the F1 hybrid larvae were maintained on Lyonia; however, on Juglans the F1 hybrid larvae grew to adulthood as well as in the control, suggesting a lack of genomic incompatibilities between the two host-associated populations. In conclusion, the results showed that the two host-associated populations are host races that are partially reproductively isolated, and that the differences in performance and preference function as strong barriers against gene flow between the host races. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 93, 135–145.

Understanding the genetics behind adaptation and reproductive isolation contributes to our knowledge about how biodiversity is created and maintained. Host races of phytophagous insects are host-associated ecotypes and have been considered as candidates for ecological speciation, but very little is known about the genetic backgrounds of host adaptations. A leaf-mining moth, Acrocercops transecta, consists of Juglans- and Lyonia-associated host races. This study assesses the genetic bases of oviposition preference and larval performance using F(1), F(2) and backcross hybrids between the two host races. Segregation patterns in the hybrid generations revealed that larval performance on Juglans is dominant, but oviposition preference for Lyonia is dominant. This result indicates that genetic components introgressed from the Lyonia race are removed from the Juglans race even though hybrid larvae are viable on Juglans. Thus, simple genetic controls with contrasting dominance directions in host-adaptation traits function as barriers to prevent a fusion of host races.

Background Researchers conducting molecular phylogenetic studies are frequently faced with the decision of what to do when weak branch support is obtained for key nodes of importance. As one solution, the researcher may choose to sequence additional orthologous genes of appropriate evolutionary rate for the taxa in the study. However, generating large, complete data matrices can become increasingly difficult as the number of characters increases. A few empirical studies have shown that augmenting genes even for a subset of taxa can improve branch support. However, because each study differs in the number of characters and taxa, there is still a need for additional studies that examine whether incomplete sampling designs are likely to aid at increasing deep node resolution. We target Gracillariidae, a Cretaceous-age (~100 Ma) group of leaf-mining moths to test whether the strategy of adding genes for a subset of taxa can improve branch support for deep nodes. We initially sequenced ten genes (8,418 bp) for 57 taxa that represent the major lineages of Gracillariidae plus outgroups. After finding that many deep divergences remained weakly supported, we sequenced eleven additional genes (6,375 bp) for a 27-taxon subset. We then compared results from different data sets to assess whether one sampling design can be favored over another. The concatenated data set comprising all genes and all taxa and three other data sets of different taxon and gene sub-sampling design were analyzed with maximum likelihood. Each data set was subject to five different models and partitioning schemes of non-synonymous and synonymous changes. Statistical significance of non-monophyly was examined with the Approximately Unbiased (AU) test. Results Partial augmentation of genes led to high support for deep divergences, especially when non-synonymous changes were analyzed alone. Increasing the number of taxa without an increase in number of characters led to lower bootstrap support; increasing the number of characters without increasing the number of taxa generally increased bootstrap support. More than three-quarters of nodes were supported with bootstrap values greater than 80% when all taxa and genes were combined. Gracillariidae, Lithocolletinae + Leucanthiza, and Acrocercops and Parectopa groups were strongly supported in nearly every analysis. Gracillaria group was well supported in some analyses, but less so in others. We find strong evidence for the exclusion of Douglasiidae from Gracillarioidea sensu Davis and Robinson (1998). Our results strongly support the monophyly of a G.B.R.Y. clade, a group comprised of Gracillariidae + Bucculatricidae + Roeslerstammiidae + Yponomeutidae, when analyzed with non-synonymous changes only, but this group was frequently split when synonymous and non-synonymous substitutions were analyzed together. Conclusions 1) Partially or fully augmenting a data set with more characters increased bootstrap support for particular deep nodes, and this increase was dramatic when non-synonymous changes were analyzed alone. Thus, the addition of sites that have low levels of saturation and compositional heterogeneity can greatly improve results. 2) Gracillarioidea, as defined by Davis and Robinson (1998), clearly do not include Douglasiidae, and changes to current classification will be required. 3) Gracillariidae were monophyletic in all analyses conducted, and nearly all species can be placed into one of six strongly supported clades though relationships among these remain unclear. 4) The difficulty in determining the phylogenetic placement of Bucculatricidae is probably attributable to compositional heterogeneity at the third codon position. From our tests for compositional heterogeneity and strong bootstrap values obtained when synonymous changes are excluded, we tentatively conclude that Bucculatricidae is closely related to Gracillariidae + Roeslerstammiidae + Yponomeutidae.

We investigated the utility of indel data for genealogical and population genetic analyses using the Tpi intron of the leaf mining moth Acrocercops transecta (Insecta: Lepidoptera). Genealogical analyses revealed that indel data were less homoplasious than DNA sequence data and that indel data contained a sufficient signal to provide a high resolution tree that was highly congruent with the tree estimated from DNA sequences. Although some conflicts were identified in the distributions of multi-residue indels, such conflicts were especially useful for the unambiguous detection of recombinations. For the first time, we adopted a Bayesian clustering method for indel characters to infer genetic structure of the moth. We concluded that indel characters have the potential to be a powerful tool in the analysis of population genetics and population structure as well as in the detection of gene flow.

Insect herbivores such as gall formers and leaf miners are often highly specialized and adapted to their respective natal host plants. Due to the specialization and adaptation, it is presumed that host shifts readily occur among closely related plant species. Leaf-mining moths, the Acrocercops leucophaea complex, consist of three species, A. leucophaea, A. defigurata, and A. transecta. Larvae of all the species of the complex feed on Juglandaceae plants, but A. leucophaea and A. transecta are also associated with an Ericaceae plant, which is quite distantly related to Juglandaceae. Such a host utilization as in this species complex is very rare among phytophagous insects. In the present study, we estimate the history of host shifts by reconstructing the phylogeny of the A. leucophaea complex using molecular data (partial sequence of mitochondrial COI, 12S rDNA, and ND5). Parsimony and maximum likelihood analyses indicated that the common ancestor of the A. leucophaea complex used Juglandaceae only, and that the association with Ericaceae has evolved in A. leucophaea and A. transecta independently. Parametric bootstrap analysis also supported multiple origins of the association with Ericaceae in this complex. These results imply that there are ecological and biochemical factors that promote host shifting between Juglandaceae and Ericaceae despite the two families being not closely related.