Honey bee visitation to sunflower: effects on pollination and plant genotype

Sunflower (Helianthus annuus L.) is an allogamic plant, which needs insects on flowering, especially the honeybees for seed production. Collecting nectar and pollen by honeybees in agricultural crops is essential to apiculture, as well as a better understanding of plant biology. The foraging behavior of Africanized Apis mellifera L. (Hymenoptera, Apidae) and its efficiency of pollination on seed yield of sunflower genotypes (open pollination and restricted pollination) were evaluated. There were peaks of visits by A. mellifera for nectar collection on the 2nd and 3rd flowering days between 7h00 and 8h30. The average density of A. mellifera during increased visitation ranged from 2.27 to 2.94 bees per capitulum. Nectar collecting bees were more frequent (2.28 bees per capitulum) than pollen collecting (0.40 bees per capitulum). On the 3rd flowering day, Helio 360 and Aguará hybrids had higher (p ≤ 0.05) number of bee visits per flower head than the other genotypes. Seed yield was 43 % higher (p ≤ 0.05) from sunflower plants that were visited by pollinator-insects compared with plants restricted to pollinators

Etude de l'impact de colza résistant aux herbicides sur l'abeille domestique

National audienc

MÉTHODE DE COMPTAGE AUTOMATIQUE DES GRAINS DE POLLEN : ÉTUDE DE LA PRODUCTION POLLINIQUE CHEZ LE TOURNESOL (HELIANTHUS ANNUUS L., COMPOSITAE)

International audienc

Apprentissage et mémoires olfactifs chez l'abeille : comparaison de différentes procédures de conditionnement classique de la réponse d'extension du probocis

International audienc

Isolation and identification of volatile constituents of sunflowers (Helianthus annuus L.)

International audienc

Isolation and identification of volatile constituents of sunflowers (Helianthus annuus L.)

International audienc

A study of rapeseed (Brassica napus L. var. oleifera Metzger) flower nectar secretions

International audienc

Expression of Protease inhibitors in Rapeseed

International audienc

Effects of artificial diet containing GNA and GNA-expressing potatoes on the development of the aphid parasitoid Aphidius ervi Haliday (Hymenoptera : Aphidiidae)

Aphid parasitoids are important biological control agents. The possibility arises that whilst foraging on insect-resistant transgenic plants, they are themselves at risk from direct and indirect effects of the expression of a transgene used to control the pest species. A liquid artificial diet was successfully used to deliver the snowdrop lectin (Galanthus nivalis agglutinin; GNA) to the peach-potato aphid, Myzus persicae. Bioassays utilising artificial diet incorporating GNA, and excised leaves of the GNA-expressing transgenic potato line, GNA2#28, were performed to assess the potential effects of GNA on the development of the aphid parasitoid Aphidius ervi. The results indicate that GNA delivered via artificial diet to the aphids can be transferred through the trophic levels and has a dose-dependent effect on parasitoid development. Parasitoid larvae excreted most of the ingested GNA in the meconium but some of it was detected in the pupae. Although A. ervi development was not affected when developing within hosts feeding on transgenic potato leaves, this probably reflected sub-optimal expression of the toxin in the transgenic potato line used<br/