Ne'eman G./Публикации

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Ne'eman G.
Автор антэкологических публикаций

, Ne'eman R.
Автор антэкологических публикаций

Journal of Pollination Ecology
Журнал с антэкологическими публикациями.

. 2017. V. 20. P. 1–12. Статья
Plants use visual signals to attract pollinators and direct them to their flowers. Visual capabilities of bees have been extensively studied mostly using artificial paper models. However, there is no empirical determination of the maximal detection distance (MDD) or minimal subtended visual angle (MSVA) of real flowers. Using a six armed radial maze, we tested MDD and MSVA of 12 types of natural and manipulated real flowers by bumble bee ( Bombus terrestris ) workers. Bees were initially trained
to obtain sugar solution at target flowers that were presented at close range on a mobile divider at the back of one of the six arms. Bees were individually marked and tested. For bees that passed the short range test, we gradually increased the distance of the target flower, until the number of successful choices reached chance level, indicating that they could not see the target flowers. The results show that MSVA of flowers is correlated with flower diameter but not with MDD. The variation in MDD to natural flowers by bumble bee workers can be best predicted by : MDD = flower coloured area / (contour line * green contrast) . Contour line length determines flower dissectedness. Full circular flowers can be detected from longer distance than dissected flowers with identical diameter. We hypothesize that dissected flower shapes might be compensated by their higher attractiveness for bees. Empirical determination of real flower MDD and MSVA is important for studying bee foraging behaviour, pollinator induced evolution of flower traits and validation of neurophysiological visual models.
Potts S.G.
Автор антэкологических публикаций

et al. (+4)
Журнал с антэкологическими публикациями.
Ecological Society of America ·,

. 2003. V. 84. No. 10. P. 2628–2642. Статья
Pollinators provide essential ecosystem services, and declines in some pollinator communities around the world have been reported. Understanding the fundamental components defining these communities is essential if conservation and restoration are to be successful. We examined the structure of plant–pollinator communities in a dynamic Mediterranean landscape, comprising a mosaic of post‐fire regenerating habitats, and which is a recognized global hotspot for bee diversity. Each community was cha
racterized by a highly skewed species abundance distribution, with a few dominant and many rare bee species, and was consistent with a log series model indicating that a few environmental factors govern the community.

Floral community composition, the quantity and quality of forage resources present, and the geographic locality organized bee communities at various levels: (1) The overall structure of the bee community (116 species), as revealed through ordination, was dependent upon nectar resource diversity (defined as the variety of nectar volume‐concentration combinations available), the ratio of pollen to nectar energy, floral diversity, floral abundance, and post‐fire age. (2) Bee diversity, measured as species richness, was closely linked to floral diversity (especially of annuals), nectar resource diversity, and post‐fire age of the habitat. (3) The abundance of the most common species was primarily related to post‐fire age, grazing intensity, and nesting substrate availability. Ordination models based on age‐characteristic post‐fire floral community structure explained 39–50% of overall variation observed in bee community structure. Cluster analysis showed that all the communities shared a high degree of similarity in their species composition (27–59%); however, the geographical location of sites also contributed a smaller but significant component to bee community structure.

We conclude that floral resources act in specific and previously unexplored ways to modulate the diversity of the local geographic species pool, with specific disturbance factors, superimposed upon these patterns, mainly affecting the dominant species.