Search results for "pollination"
showing 10 items of 114 documents
Potential impact of genetically modified Lepidoptera-resistant Brassica napus in biodiversity hotspots: Sicily as a theoretical model
2016
The general increase of the cultivation and trade of Bt transgenic plants resistant to Lepidoptera pests raises concerns regarding the conservation of animal and plant biodiversity. Demand for biofuels has increased the cultivation and importation of oilseed rape (Brassica napus L.), including transgenic lines. In environmental risk assessments (ERAs) for its potential future cultivation as well as for food and feed uses, the impact on wild Brassicaeae relatives and on non-target Lepidoptera should be assessed. Here we consider the potential exposure of butterflies as results of possible cultivation or naturalization of spilled seed in Sicily (Italy). Diurnal Lepidoptera, which are pollinat…
Quantitative importance of staminodes for female reproductive success inParnassia palustrisunder contrasting environmental conditions
2003
The five sterile stamens, or staminodes, in Parnassia palustris act both as false and as true nectaries. They attract pollinators with their conspicuous, but non-rewarding tips, and also produce nectar at the base. We removed staminodes experimentally and compared pollinator visitation rate and duration and seed set in flowers with and without staminodes in two different populations. We also examined the relative importance of the staminode size to other plant traits. Finally, we bagged, emasculated, and supplementary cross-pollinated flowers to determine the pollination strategy and whether reproduction was limited by pollen availability. Flowers in both populations were highly dependent o…
Latgales tradicionālā biškopība un tās ilgtspējīga attīstība
2019
Biškopības produkti ieņem īpašu vietu pārtikas, medicīnas un kosmētikas produktu nodrošinājumā cilvēku sabiedrībai, bet papildus šiem ekosistēmu pakalpojumiem bites nodrošina – savvaļas un lauksaimniecības augu apputeksnēšanu. Bišu skaita straujā samazināšanās pasaulē mūsdienās kļuvusi par vienu no aktuālākajām vides problēmām. Latvijā līdz šim nebija veikti pētījumi par biškopības stāvokli. Bakalaura darbā apkopoti galvenie Latvijas biškopības stāvokli raksturojošie dati, aptaujas dati par biškopības produktu popularitāti iedzīvotāju vidū Rīgā. Sīkāk raksturots biškopības stāvoklis un attīstības perspektīvas Latgalē, analizētas intervijas ar biškopjiem. Pēc biškopju vērtējuma nozare Latvij…
Black currant project: Multidisciplinary approach to agro-ecological measures
2022
The decline of wild pollinators leads to a drastic drop in the associated ecosystem service, resulting in significant lossesin agricultural yields. The production of blackcurrant “Noir de Bourgogne” could potentially be tripled, if populationsof wild pollinators were restored. Various agroecological measures beneficial to pollinators are discussed here, as wellas ongoing experimental tests. We discuss the practical possibilities of implementing these measures by blackcurrantgrowers as well as the technical locks that still exist. The return to an agroecological equlibrium for which pollinationbecomes again a free ecosystem service for agriculture, requires the integration of multiple agroec…
La pollinisation du cassis : État des lieux dans un contexte de changements anthropiques.
2019
Cultivated plants are part of their agroecosystem. Recent anthropic changes modified and decreased the wildcompartment of agroecosystems leading to a lowering of ecosystemic services such as pollination. Blackcurrant ispollinated at least partially by insects. In a study on 8 sites in Côte-d’Or, Burgundy, France we showed that pollinatordensity is lower than 0.5 pollinators per minute of observation in blackcurrant orchards. Blackcurrant are preferentiallyvisited by Bombus sp. and to a lesser extent by Andrena and Apis sp. Comparison of pollinator abundance between2018 data and data from ancient publications show that even if the floral abortion rate did not vary significantly, thenumber of…
Contribution des pollinisateurs dans la production de colza et de tournesol en zone atelier « Plaine et Val de Sèvre »
2018
Insect pollination is essential for over 70% of crops around the world. However, the contribution of pollinators to crop production and the insects involved in crop pollination have rarely been studied. Moreover, assessments of pollinator contributions have mostly been conducted on a small scale or under simplified conditions, which do not represent the real contributions at the field scale and do not take into account possible interactions between pollinators and farming practices. The aim of this study is to quantify directly under field conditions, the contribution of pollinators in two crops frequently cultivated in Europe: oilseed rape and sunflower. Estimations are realized both at th…
Should we manage weeds for bees ?
2014
National audience
Breeding system and conservation strategy of the extremely endangered Cistus carthaginensis Pau (Cistaceae) of Spain
2001
Cistus carthaginensis is one of the most endangered plants in Europe: at present there exist only a few individuals in Murcia and one in Valencia (SE and E Spain). To design an adequate conservation strategy able to avoid the extinction of this species, various aspects of its reproductive biology were studied. The extreme rarity of C. carthaginensis is not related to problems of development and/or fertility of pollen or ovules produced by the few existing specimens. Meiosis in the pollen mother cells is always regular and chromosome segregation is completely equilibrated in the male gametes. Pollen and ovule production is high and similar to that reported for other related species of Cistus…
Pollination of four sympatric species ofAngelonia (Scrophulariaceae) by oil-collecting bees in NE. Brazil
1991
The manner whereby the oil-producing bisaccate flowers ofAngelonia (Scrophulariaceae) are pollinated by female oil-collecting bees is reported for the first time. Observations were made in the Caatinga formation of Pernambuco, NE. Brazil, on four synchronopatric species. These differ in sizes and structural details of the corolla, level of flower exposition, and habitat preferences. All legitimate visitors wereCentris spp. (Anthophoridae):Angelonia hirta was mainly pollinated byC. fuscata andA. pubescens byC. hyptidis; A. bisaccata andA. hookeriana shared an unidentified species. Several exomalopsine, tetrapediine and meliponid bees exploit the flowers less descriminately for oil or pollen,…
The perfume flowers ofCyphomandra (Solanaceae): Pollination by euglossine bees, bellows mechanism, osmophores, and volatiles
1993
The perfume syndrome and pollination by fragrance-collecting euglossine bees in the neotropic solanaceous genusCyphomandra was confirmed by field observations. In SE Brazil,C. sciadostylis was visited byEufriesea violaceae, andC. diploconos byEuglossa mandibularis; C. hartwegii was pollinated byEulaema meriana in Costa Rica. The primary attractant, fragrant droplets that ooze from the dorsally bulged connectives, is mopped up by the males with the forebasitarsi. Thereby, the poricidal thecae are inadvertently pushed causing the dry pollen to dust the bee's sternum. The number and direction of the pollen jets are related to pollinator size and stigma structure. The flowers are homogamous, se…