The Reproductive Biology of Raspberries and Plant‐pollinator Community Structure

Abstract

Rubus idaeus and Rubus pubescens are congeners which differ with respect to their life history patterns. Rubus idaeus is locally important in the Northeast in areas subject to windthrow, fire, and man‐made disturbances, while R. pubescens often forms a significant portion of the ground cover of shaded, damp, woodland areas. The life history pattern of R. idaeus is based upon the short term build up and slow decay of a large seed bank. Vegetative reproduction is more important in the eventual spread of R. pubescens. The reproductive traits of the two species reflect many of the above mentioned constraints and differences. Rubus pubescens produces relatively small quantities of nectar and flowers during a brief 1–2‐wk period late in May. Synchronous flowering probably minimizes the incidence of floral predation and makes the low nectar flowers more attractive by reducing the pollinators' flight time. Rubus idaeus is an abundant species, which offers almost unlimited supplies of nectar during at least part of its extended 3–4‐month flowering season. It is attractive to a wide range of pollinators and has figured prominently in the design, phenology, and reward structure of the early successional northern hardwoods plant‐pollinator community.

Population evaluation in crop wild relatives for in situ conservation: a case study for raspberry Rubus idaeus L. in the Leningrad region, Russia

“…This is confirmed by the results of DNA analysis on wild raspberry, revealing high level of genetic diversity (Antonius and Nybom 1994;Graham et al 1997). Besides, the variability of clumps of this species is increased due to the fact that most plants arose as a result of cross-pollination, producing genetically heterogeneous plants (Keep 1968;Whitney 1984).…”

Responses of insect pollinators and understory plants to silviculture in northern hardwood forests

“…Other studies have documented large increases in raspberry post-harvest, in spruce stands in northwestern Ontario (Fye 1972), in strip-cuts in New Hampshire (Whitney 1984), and in hardwood forests (Roberts and Dong 1992;Romey et al 2007;Falk et al 2010). Whitney (1984) found that raspberry attracted mainly bees, but in this study, syrphids utilized it extensively as well. Twenty-four syrphid and 14 bee species were collected on the flowers of raspberry (Appendices 2 and 3).…”

“…Once established, it spreads and reproduces mainly through root suckers and rhizomes, forming monospecific communities that monopolize resources such as nutrients, moisture, space, and light (Oleskevich et al 1996). Other studies have documented large increases in raspberry post-harvest, in spruce stands in northwestern Ontario (Fye 1972), in strip-cuts in New Hampshire (Whitney 1984), and in hardwood forests (Roberts and Dong 1992;Romey et al 2007;Falk et al 2010). Whitney (1984) found that raspberry attracted mainly bees, but in this study, syrphids utilized it extensively as well.…”

“…Its reliance on pollinators explains why it produces copious, high-quality nectar. Whitney (1984) found that it produced an average of 4.29 mg sugar/flower/day, or about 18 kg/ha for four-year old strip-cut sites in New Hampshire. This amount of nectar is an order of magnitude more than other species (e.g.…”

“…This amount of nectar is an order of magnitude more than other species (e.g. Rubus pubescens produced 0.12 mg; Whitney 1984). In the harvested treatments, raspberry dominated in the canopy gaps, and it was there where the majority of syrphids and bees were caught.…”