Search

Key message Pollination is a key step for fruit production. To provide a tool for future in-depth analysis of pollination in chestnut, we describe in detail a chestnut orchard (location, genotype, phenotype and seed-set of all trees). Context Chestnuts, which are insect-pollinated trees, have been massively planted around the world for nut production. Orchards are planted with clonal varieties selected from crosses between the European chestnuts (Castanea sativa) and Japanese chestnuts (C. crenata) or Chinese chestnuts (C. mollissima) because these two last species are tolerant to blight and ink diseases. Aims To characterize chestnut genetic resources and accurately model male and female fitness as well as pollen exchanges in orchards, we characterized all chestnuts of the INRAE chestnut germplasm collection located near Bordeaux (France). Methods All chestnut trees were geolocated and genotyped using 79 SNP and 98 SSR loci. We scored their flowering phenology using chestnut BBCH scale and precisely described their phenotype (height, diameter a breast height (DBH), canopy diameter…), their capacity to produce pollen (flower type, catkins length…) and their fruit production (number of burrs, seed-set…). Results We geolocated 275 trees and genotyped 273 of them. We identified 115 unique genotypes and assigned each genotype to species. To assess phenology, we evaluated 244 trees twice a week, for 6 weeks from early June to mid-July. We also described tree phenotypes with 11 variables, pollen production with 5 variables and fruit production with 3 variables. All measures were recorded in 2018 except seed set that was measured two consecutive years, in 2018 and 2019. Conclusion The data collected is very detailed and allows modelling precisely pollen exchanges between trees. Parts of this data have been successfully published in scientific articles. Data are available at: https://data.inrae.fr/dataset.xhtml?persistentId=doi:10.15454/GSJSWW Associated metadata are available at:https://metadata-afs.nancy.inra.fr/geonetwork/srv/fre/catalog.search#/metadata/02c5ca07-1536-4f89-9a0c-9e8d44a91287

This masters thesis studies the influence of species diversity of bloomig flowers in the flower strips on the composition of pollinators community, which is wisiting the flower strips. The flowers are blooming plentiful during the whole season and therefore they are providing resources for the functional groups of pollinators. Therefore these flower strips are helping to increase the biodiversity in cities.

The special mixed reproductive system, i.e., the ability of an individual plant to develop both open, chasmogamous (CH) flowers adapted to cross-pollination and closed, cleistogamous (CL) flowers with obligate self-pollinating, is a common phenomenon in Viola L. In most sections of Northern Hemisphere violets, cleistogamy is seasonal, and CH and CL flowers develop sequentially in the season. Non-seasonal cleistogamy (simultaneous) is a rare phenomenon in rostrate violets. In the current study, we focused on modification of the CH/CL mating system in V. caspia by environmental conditions, resulting in a gradual switch from temporal cleistogamy, occurring in nature, to simultaneous cleistogamy under greenhouse conditions. V. reichenbachiana with seasonal cleistogamy was the control for V. caspia with the labile seasonal/simultaneous cleistogamy system. In simultaneous cleistogamy, the CH and CL flowers, fruits and seeds developed on an individual plant at the same time on the same branch. The typical difference between CH and CL flowers’ pistils is a straight style ending with a head-like stigma in CH and a curved style in CL adapted to self-pollination. This trait persists in the fruit and seed stages, allowing for easy recognition of fruit of CL and CH flowers in simultaneous cleistogamy. Floral meristems of CH flowers of V. reichenbachiana developed on the rhizome at the end of the growing season under short-day conditions and remained dormant until the following season. The CL floral meristems formed under long-day conditions on elongating lateral branches in the upper leaf axils. The daily temperature influenced the variable CH/CL ratio of V. caspia in nature and greenhouse conditions. Regulation of the CL/CH flower ratio by modifying environmental factors is important for basic research on genetic/epigenetic regulation of cleistogamy and for practical use to produce genetically stable lines of economically important species via CL seeds.

The aim of this study was to analyse wild bee-plant interactions in Madeira Island and construct anetwork structure covering the largest parts of the island and most altitudes and habitat types. The interaction datawere sampled at 179 localities from 1989 to 2012 mainly by the authors; additionally, data from the collections of theLaboratório Agrícola da Madeira, Camacha (ICLAM) and the Museu de História Natural do Funchal, Madeira, Portugal,were used. Twelve wild-bee species (the complete species pool of permanently established Madeiran wild-beespecies) were collected or observed on 81 plant taxa (belonging to 30 plant families). The total dataset from MadeiraIsland includes 637 data points of bee-plant interactions. We assigned the data set to the main thermotypes – infra- /thermo-Mediterranean zone as well as meso-Mediterranean / temperate zone – and constructed two networks. Incontrast to most of the mainland networks of temperate and Mediterranean ecosystems with more wild-bee thanplant species, the bee-plant networks demonstrate high asymmetry, with many more plant than bee species. Thisphenomenon has also been documented, e.g., in Porto Santo (Madeira Archipelago). Wild-bee species and plantspecies were highly interconnected within the network, showing that even under difficult and strong climaticconditions with unequal resource availabilities, there were enough alternatives for obtaining food resources. Ten ofthe wild-bee species are euryanthic, with only two species (the introduced Hylaeus pictipes and the endemic Andrenamaderensis) showing stenanthy. The high individual numbers and euryanthic behaviour of most wild-bee speciesmet the precondition for network stability. The plant families with the highest importance as food resources are in the orders Asteraceae (51%), Brassicaceae (14%), Fabaceae (8%) and Boraginaceae (8%). These offer different flowertypes (actinomorphic, zygomorphic, Asteroideae and Cichorioideae types) and a variability of flower types for wild-bee species of different body sizes and foraging behaviour. Similar to the results of the bee-plant network of PortoSanto, most of the foraged plant species were endemic or native species. Introduced and cultivated plant speciesmainly showed minor importance. We found no disturbances of the network by the introduced masked bee Hylaeuss. signatus and the probably introduced bumblebee Bombus r. ruderatus. Differences and similarities between thebee-plant networks of Madeira Island (infra- / thermo-Mediterranean zone) and the corresponding areas of the mucholder island Porto Santo (xeric- / infra-Mediterranean zone) are discussed in this paper

An analysis of the anthophilous fauna of N.W. Europe is presented, stressing the role plants play for insects. The study is based on some 29,000 relations between about 2,600 insect species and 1,300 plant species (569 genera). The data are derived from our database (“CrypTra”) of biotic relations between Cryptobiota and Tracheophyta, that is based on published sources. It is suggested that a ratio of 2 to 5 anthophilous insect species per entomophilous plant species is the rule in N.W. Europe, where other types of zoophily are virtually absent. A small minority of the plant species/genera play a disproportionally important role as hosts to flower visitors; many of these so-called cornucopian taxa belong to the commonest entomophilous plants in the region, and occur also in moderately disturbed habitats. There is a significant positive correlation between the commonness of a plant species and the fraction this plant represents of the trophic resources exploited by an insect species. There is, on the other hand, a significant negative correlation between the number of insect species visiting a given plant species, and the number of plant species visited by a given insect species. These two elements together demonstrate that the anthophilous fauna and the entomophilous flora of N.W. Europe as a whole form a loose system, not predominantly characterised by specialisation. In accordance with this, factor analysis suggests that there is no ground to recognise more than three visitor types, viz., the allotropous, hemitropous, and eutropous visitors as defined by Loew. A minority of the plant taxa – essentially the cornucopian ones – can with some difficulty be associated with these three types of visitors, and a very few narrowly specialised plant taxa can be associated with more specific visitor groups. However, the large majority of plants cannot be fitted in any typology. These results have practical implications for the nature management of the anthophilous fauna, in that the important role of the cornucopian floral element is underlined. The fact that the majority of the cornucopian species are perennial, or even woody, places constraints to agricultural practices intended to foster beneficial anthophilous insects.

An analysis of the anthophilous fauna of N.W. Europe is presented, stressing the role plants play for insects. The study is based on some 29,000 relations between about 2,600 insect species and 1,300 plant species (569 genera). The data are derived from our database (“CrypTra”) of biotic relations between Cryptobiota and Tracheophyta, that is based on published sources. It is suggested that a ratio of 2 to 5 anthophilous insect species per entomophilous plant species is the rule in N.W. Europe, where other types of zoophily are virtually absent. A small minority of the plant species/genera play a disproportionally important role as hosts to flower visitors; many of these so-called cornucopian taxa belong to the commonest entomophilous plants in the region, and occur also in moderately disturbed habitats. There is a significant positive correlation between the commonness of a plant species and the fraction this plant represents of the trophic resources exploited by an insect species. There is, on the other hand, a significant negative correlation between the number of insect species visiting a given plant species, and the number of plant species visited by a given insect species. These two elements together demonstrate that the anthophilous fauna and the entomophilous flora of N.W. Europe as a whole form a loose system, not predominantly characterised by specialisation. In accordance with this, factor analysis suggests that there is no ground to recognise more than three visitor types, viz., the allotropous, hemitropous, and eutropous visitors as defined by Loew. A minority of the plant taxa – essentially the cornucopian ones – can with some difficulty be associated with these three types of visitors, and a very few narrowly specialised plant taxa can be associated with more specific visitor groups. However, the large majority of plants cannot be fitted in any typology. These results have practical implications for the nature management of the anthophilous fauna, in that the important role of the cornucopian floral element is underlined. The fact that the majority of the cornucopian species are perennial, or even woody, places constraints to agricultural practices intended to foster beneficial anthophilous insects.