14 research outputs found
Flora visitata da alcuni insetti e relativo ruolo nell'impollinazione delle colture agrarie
FLORA FORAGED BY SOME INSECTS AND RELA TIVE ROÌLEÂ IN THE POLLINATION OF THE AGRICULTURAL CULTIVATIONS The flora foraged by 32 pollinator insects was observed in a surrounding rich in following and overlaping flowerings. Apis mellifera ligustica Spin. solves the majority impollination problems of tre agricultural cultivations. Bombus spp. replace profiÌtably the honeybee for the early cultivations or in presence of Iow temperatures or in superior altitudinal zones (1,000 m s.I.); Osmia spp. show themselves to be very effective on the fruit trees; Ombelliferae take advantage of Syrphidae, Muscidae, Calliphoridae, Prosopis punctata BrulleÌ, Andrena spp., Halictus spp., Lasioglossum spp. visits. Medicago sativa L. could mainly take advantage of Megachile spp. service. The pollinator entomofauna should profit by undisturbed areas or in specific cases should be breeded in view of the pollination of the cultivations in glasshouses or the one's in open field.In un ambiente ricco di fioritura scalari ed accavallantisi eÌ stata osservata la flora visitata da 32 insetti pronubi. Apis mellifera ligustica Spin. risolve la maggior parte dei problemi inerenti l'impollinazione delle colture agrarie. Bombus spp. sostituiscono vantaggiosamente l'ape al cospetto di colture precoci o in presenza di basse temperature o nelle fasce altitudinali superiori ( 1000 m s.l.m.); Osmia spp. si rivelano molto efficaci sui Frut- tiferi; le Ombrellifere traggono profitto dalle visite di Syrphidae, Muscidae, Calliphoridae, Prosopis punctata BrulleÌ, Andrena spp., Halictus spp., Lasioglossum spp. Medicago sativa L. potrebbe usufruire soprattutto del servizio di Megachile spp. L'entomofauna pronuba dovrebbe beneficiare della presenza di appropriate aree di rispetto e in casi specifici essere allevata per l'impollinazione delle colture protette e in pieno campo.
- Indagini di laboratorio e di pieno campo sulla dieta di Osmia rufa cornigera Rossi (Hymenoptera, Megachilidae)
Osservazioni sugli insetti impollinatori del cartamo (Carthamus tinctorius L.) in Umbria.
Botanical and geographical characterisation of honeys in Diamante, Entre RĂos, Argentina
Male flowers in Tulipa pumila
We found functionally male individuals in an otherwise hermaphroditic population of Tulipa pumila (Liliaceae) located in Tuscany (central Italy). We investigated the sex ratio of this population, followed by morphometric analyses of the scape, leaves and flowers, and tests on pollen germinability and seed number and mass, in order to infer which sexual strategy produced the observed co-occurrence of male and hermaphrodite individuals. We found that sex ratio deviated from 1:1, and functionally male individuals showed a smaller plant size and a reduced pollen fitness (germinability and siring ability) compared to hermaphrodites. These findings point to a resource-dependent sexual allocation strategy, probably associated with gender diphasy