Préliminaires sur la production de nectar chez trois espèces de Vaccinium

Abstract

Résumé — Les sécrétions nectarifères de la myrtille (Vaccinium myrtillus L), de

Early spring floral foraging resources for pollinators in wet heathlands in Belgium

“…The amounts observed here were low compared to other studies on V. myrtillus (Jacquemart 1992), but can be explained by dry weather conditions during early spring 2014. Nectar of V. myrtillus is sucrose dominant.…”

“…In the Ardenne, High Belgium, the flowering season starts as early as March or April (Lambinon and Verloove 2012). Salix x multinervis thus constitutes the first flowering species in wetlands and wet heathlands (Jacquemart 1992). Willows are dioecious and bear catkins; they are known to attract numerous oligolectic solitary bee species, such as Andrena spp.…”

Nectar foragers contribute to the pollination of buzz‐pollinated plant species

“…On the Vaccinium species, we showed that buzzing visitors were far more effective for pollen deposition than legitimate nectar visitors. Furthermore, the higher nectar quantity of these plants attracted nectar foragers (Jacquemart, 1992; Stephens, 2013; Moquet et al, 2017). Nectar production is not frequent in buzz‐pollinated species (Buchmann, 1983; Knudsen and Olesen, 1993; De Luca and Vallejo‐Marín, 2013).…”

“…Vallejo‐Marín et al (2010) reported nectar secretion in all species belonging to three poricidal plant families (out of 14 studied families). For example, Ericaceae have poricidal anthers and produce large amounts of nectar (Jacquemart, 1992; Moquet et al, 2017). Other studies of the pollination effectiveness for buzz‐pollinated flowers have only examined pollen collection in nectarless flowers (Proença, 1992; Larson and Barrett, 1999; Kawai and Kudo, 2009; De Luca and Vallejo‐Marín, 2013).…”

Tree-dimensional resources: hedgerow and orchard pollen for bumble bees

“…One remarkable tree species is the willow (Salix spp. ; Salicales: Salicaceae) that represents an important resource for spring bee species, particularly in wetlands and wet heathlands, blooming in early spring and offering a huge amount of nutritive and easily accessible pollen (e.g., [49][50][51]). However, riparian zones and their associated willows are declining, notably as a consequence of stream diversions, groundwater pumping, extended drought, and replacement with less desirable shrubs and trees [52][53][54], thereby threatening bumble bee colony establishment.…”