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Agromyzidae (Insecta: Diptera) is a cosmopolitan family of acalyptrate flies, with almost 3,000 species worldwide distributed. Most species are leaf miners on a large number of plants. Among them, Liriomyza Mik, 1894 is a large genus of leaf-miner species that can cause significant damage to economically important crops and is considered agricultural pests, such as Liriomyza sativae Blanchard, 1938 and Liriomyza huidobrensis (Blanchard, 1926), which are herein investigated. The present study deals with the impact of climatic factors (temperature, humidity, and precipitation), seasonality, and parasitoid abundance on leaf-miner infestation during one year in five cultivated crops in Northeastern Brazil. Climatic factors for instance had different effects on L. sativae populations in melon and watermelon crops. Larval abundances were greater during the dry season for both species, L. sativae and L. huidobrensis, and abundance of adult parasitoids followed the increase of mining larvae.

International audience; As phytohormones lie at the very core of molecular mechanisms controlling the plant physiology and development, they have long been hypothesized to be involved in insect-induced plant manipulations. Cytokinins (CKs) are phytohormones now widely recognized to be utilized by leaf-mining and gall-inducing insects in the control of the physiology of their host plant. In some leaf-mining moth species, larvae can supply the hormones themselves, bacterial symbionts contributing to the production of CKs. Our objective was to investigate whether closely related leaf-miner species sharing the same ecological niche but differing in their Wolbachia infection status develop similar strategies to manipulate their host plant. An extensive identification and quantification of CKs has been used to elucidate physiological patterns relevant for the plant-insect interactions. Our results show that modulation of plant CK levels is impaired in the Wolbachia-free leaf-mining moth Phyllonoryc-ter mespilella (H€ ubner) (Lepidoptera: Gracillariidae) contrasting with results previously observed in the closely related moth species Phyllonorycter blancardella (Fabricius) that produce and deliver CKs to the plant through an intricate interaction with Wolbachia. Our study suggests that mechanisms underlying colonization of the host plant and adaptation to fluctuating environmental conditions are different between the two leaf-miner species and that P. mespilella larvae most likely do not produce CKs. This species rather only buffers the degradation of CKs naturally occurring during the senescence of leaves leading to few active CKs being maintained at a sufficiently high level to induce and maintain a 'green island' phenotype (photosynthetically active green patches in otherwise senescing leaves). This study further provides converging experimental evidence pointing toward the influence of bacterial symbionts in the ability of leaf-mining moths to control the physiology of their host plant with consequences for their ecology and evolutionary diversification.

The sawfly genusHeterarthrusis naturally distributed in the Palaearctic, with a single described Oriental species. Their larvae mine in the leaves of trees and shrubs of Salicaceae, Betulaceae, and Sapindaceae (Acer). We here recognise twelve West Palaearctic species as valid, with the status of two additional nominal species group taxa in need of further study:fruticicolumErmolenko, andsmithiErmolenko. A key to adults of the species occurring in the West Palaearctic is presented. Two new species are described:Heterarthus vikbergiListon, Mutanen & Viitasaari,sp. nov.from females and males reared from leaf-mines inPopulus balsamiferacollected in eastern Finland, andHeterarthrus fioraListon,sp. nov.from females reared fromAcer pseudoplatanus. The latter is a widespread European species, previously misidentified asHeterarthrus aceris(Kaltenbach, 1856). New junior subjective synonyms arePhyllotoma acerisKaltenbach, 1856 ofHeterarthrus leucomela(Klug, 1818),H. aihinoensisHaris, 2006 ofH. kamtchaticus(Malaise, 1931) sp. rev., andH. imbrosensisSchedl, 1981 ofH. wuestneii(Konow, 1905). Lectotypes are designated forPhyllotoma flavicollisGussakovskij, 1947,P. kamtchaticaMalaise, 1931, andTenthredo ochropodaKlug, 1818.

International audience; Hypermetamorphosis has been described in several Lepidoptera leaf-miner species (mostly Gracillariidae, Epipyropidae, and Phyllocnistidae) and can be defined as a strong modification of the larval morphology associated with a switch in its feeding mode. Evolution of this larval feeding strategy presumably influences nutritional resources that can be exploited and has strong consequences for plant morphology. The following studyfocuses on Phyllonorycter blancardella (Lepidoptera: Gracillariidae), a leaf-miner developing on Malus domestica. We characterize the morphology of larval mouthparts and the resulting morphological impact on leaf tissues. Our results show that first instars do not strongly affect the leaf anatomy and leave most plant cells intact, while later instars significantly disrupt leaf tissues. Additionally, young larvae are ‘‘fluid-feeders’’ and feed on plant cell fluids resulting from the progression of the larvae through the lower layer of the leaf spongy parenchyma. They occupy a feeding niche clearly distinct from later instars that are ‘‘tissue-feeders’’. Hypermetamorphosis in P. blancardella most likely allows insects to cope with a confined nutritional space by partitioning the limited feeding resources, and may help leaf-miners to optimize their nutrition

The choices made by insects at different stages of their life cycle are critical for the individual and progeny success. In the case of leaf-miners, during larval development they are not able to make choices until the emergence from the leaf, after which the larva falls to the ground and begins pupation. According to needs, preferences and soil properties, the larva could achieve a suitable substrate for the development of the pupa. Our aim was to study the preferences for pupation substrates of Notofenusa surosa larvae, leaf-miners of Nothofagus obliqua, in relation to soil properties. We selected different types of substrates (including volcanic ash) and conducted paired preference tests. The substrate was considered chosen when the larva selected it and formed the pupa (response variable). According to data obtained, several models were performed to determine the probability of individuals to choose a particular option depending on its preferences and substrates´ properties. These larvae are able to discriminate the different options offered and choose their pupation substrate according to the percentage of organic matter. Fil: Pietrantuono, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; Argentina Fil: Enriquez, Andrea Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Area de Recursos Naturales; Argentina Fil: Fernandez Arhex, Valeria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Area de Recursos Naturales; Argentina Fil: Bruzzone, Octavio Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Area de Recursos Naturales; Argentina