Young honeybees show learned preferences after experiencing adulterated pollen

Pollen selection affects honeybee colony development and productivity. Considering that pollen is consumed by young in-hive bees, and not by foragers, we hypothesized that young bees learn pollen cues and adjust their preferences to the most suitable pollens. To assess whether young bees show preferences based on learning for highly or poorly suitable pollens, we measured consumption preferences for two pure monofloral pollens after the bees had experienced one of them adulterated with a deterrent (amygdalin or quinine) or a phagostimulant (linoleic acid). Preferences were obtained from nurse-aged bees confined in cages and from nurse bees in open colonies. Furthermore, we tested the bees’ orientation in a Y-maze using a neutral odour (Linalool or Nonanal) that had been previously associated with an amygdalin-adulterated pollen. Consumption preferences of bees, both in cages and in colonies, were reduced for pollens that had been adulterated with deterrents and increased for pollens that had been supplemented with linoleic acid. In the Y-maze, individuals consistently avoided the odours that they had previously experienced paired with the deterrent-adulterated pollen. Results show that nurse-aged bees associate pollen-based or pollen-related cues with either a distasteful/malaise experience or a tasty/nutritious event, leading to memories that bias their pollen-mediated response.

Особенности мужского гаметофита томата в условиях вирусного патогенеза и водного дефицита

On the example of F1 hybrid combinations and tomato varieties, the possibility of the assessing method for pollen selection on the responses of male gametophytes under conditions of viral pathogenesis and drought has been shown. It was found the action of factors on the pollen viability and on the rate of pollen tubes growth, leading to the manifestation of differential reactions. The viruses are the main sources of variability of the pollen functional traits, while the effect of water deficit and genotype are considerably weaker. Genotypes that combine the high viability of pollen with the ability to form longer pollen tubes under the complementary action of viruses and water deficit have been identified, suggesting the prospect of these genotypes using in further breeding studies.

Young bumblebees may rely on both direct pollen cues and early experience when foraging

An adequate supply of macro- and micronutrients determines health and reproductive success in most animals. Many bee species, for example, collect nectar and pollen to satisfy their demands for carbohydrates, protein and fat, respectively. Bees can assess the quality of pollen by feeding on it, but also pre-digestively by means of chemotactile assessment. Whether they additionally use larval nutritional experience, as has been shown for Drosophila melanogaster and Bombyx mori , is unknown. In this study, we tested whether pollen selection of bumblebee foragers is affected by nutritional experience (acquired before the onset of foraging) or solely by food quality. Bumblebee larvae were fed with one out of three different pollen blends. As adults, they were offered all three blends when they started foraging for the first time. We found all treatment groups to prefer one out of the three blends. This blend provided the highest nutritional quality and increased the bees' lifespan, as shown by feeding studies with microcolonies. Besides, bees also chose the pollen blend fed during their larval stage more often than expected, indicating a significant effect of pre-foraging experience on adult pollen foraging behaviour. The combination of both direct pollen quality assessment and pre-foraging experience (i.e. during the larval phase or as early imagines) seems to allow foraging bumblebees to efficiently select the most suitable pollen for their colony.

Pollen Selection for Drought Tolerance in Sunflower

The drought resistance and genetic structure of F2 sporophytic populations for some morphological marker traits after pollen selection for water stress tolerance in F1 sunflower hybrids has been studied. The emasculated inflorescences were moistened with 10% and 20% of PEG 6000 solution in the experiments and with distilled water in the control. Freshly collected pollen was used for pollination after drying up the PEG solution on stigmas. F2 resulted seeds were germinated in 20% solution of PEG 6000 for a period of 3 days, and then the percentage of seed germination was counted. Germinated and not germinated seeds were separately planted. Segregation ratios in F2 populations for leaf venation and leaf chlorophyll deficiency marker traits were analyzed at early stage of development. Pollen treatment significantly increased the drought resistance of F2 populations and changed the monogenic ratios for leaf chlorophyll deficiency marker trait.