Aging effect on nectar production in two clones of Asclepias syriaca

In common milkweed ( Asclepias syriaca ), flower nectar volumes, concentration and sugar production varied according to the age of the sampled blossoms. In individual blossoms, nectar production peaked daily at 0800 hr. Peak production during the life of the flower occurred on the second day of flowering, 50 h after anthesis, and nectar production ceased after 120 h. The amount and quality of nectar were affected by microclimatic conditions and varied between clones. However, the same secretory patterns were found in all flowers studied. This age dependent nectar secretion combined with the sequential mode of flowering found on a single stem, results in substantial reward for extended periods to nectar feeders.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47744/1/442_2004_Article_BF00378227.pd

Towards elucidating the differential regulation of floral and extrafloral nectar secretion

Nectar is a rich source of sugars that serves the attraction of pollinators (floral nectar) or predatory arthropods (extrafloral nectar). We just begin to understand the similarities and differences that underlie the secretory control of these two important types of plant secretions. Jasmonates are phytohormones, which are well documented to be involved in plant developmental processes and plant defence responses against herbivores, including the secretion of extrafloral nectar. Recently, jasmonates have also been implicated in the regulation of floral nectar secretion in Brassica napus. Due to a trade-off between reproduction and defence, however, plants need to functionally separate the regulation of these two secretory processes. In line with this prediction, externally applying jasmonates to leaves did indeed not affect floral nectar secretion. Here we compare the current knowledge on the regulation of floral and extrafloral nectar secretion to understand similarities and dissimilarities between these two secretory processes and highlight future research directions in this context

EGFR gene methylation is not involved in Royalactin controlled phenotypic polymorphism in honey bees

The 2011 highly publicised Nature paper by Kamakura on honeybee phenotypic dimorphism, (also using Drosophila as an experimental surrogate), claims that a single protein in royal jelly, Royalactin, essentially acts as a master "on-off" switch in development via the epidermal growth factor receptor (AmEGFR), to seal the fate of queen or worker. One mechanism proposed in that study as important for the action of Royalactin is differential amegfr methylation in alternate organismal outcomes. According to the author differential methylation of amegfr was experimentally confirmed and shown in a supportive figure. Here we have conducted an extensive analysis of the honeybee egfr locus and show that this gene is never methylated. We discuss several lines of evidence casting serious doubts on the amegfr methylation result in the 2011 paper and consider possible origins of the author's statement. In a broader context, we discuss the implication of our findings for contrasting context-dependent regulation of EGFR in three insect species, Apis mellifera, D. melanogaster and the carpenter ant, Camponotus floridanus, and argue that more adequate methylation data scrutiny measures are needed to avoid unwarranted conclusions