Recent research

Landing lights for bumblebees

Gardeners could help maintain bumblebee populations by growing plants with red flowers or flowers with stripes along the veins, according to field observations of the common snapdragon Antirrhinum majus at the John Innes Centre in Norwich, UK. "Stripes following the veins of flowers are one of the most common floral pigmentation patterns so we thought there must be some advantage for pollination," said Professor Cathie Martin.

The study compared the number of visits by bumblebees to various cultivars of the plant, and the number of flowers visited per plant. Red flowers and those with venation patterning were visited significantly more frequently than white or pink, and more flowers were visited per plant. "Stripes provide a visual guide for pollinators, directing them to the central landing platform and the entrance to the flower where the nectar and pollen can be found. We examined the origin of this trait and found that it has been retained through snapdragon ancestry. The selection pressure for this trait is only relaxed when full red pigmentation evolves in a species," said Professor Martin.

Bumblebees are the main pollinators for snapdragon because the weight of the bee is needed to open the flower. Pollinators learn and memorise floral signals, such as flower shape, scent, colour and patterns of pigmentation. They return to flowers from which they have previously found food. Simple changes due to single gene changes can have dramatic effects on which flowers pollinators visit, and how often.

Collaborators on the project from New Zealand also analysed how the stripy patterns are formed along the veins of the common snapdragon. They showed that two signals interact to create the stripes. "Complex colour patterns such as spots and stripes are common in nature but the way they are formed is poorly understood," said Dr Kathy Schwinn from the New Zealand Institute for Plant & Food Research. "We found that one signal comes from the veins of the petals and one from the skin of the petals, the epidermis. Where these signals intersect, the production of red anthocyanin pigments is induced."

PHOTO © BIOTECHNOLOGY AND BIOLOGICAL SCIENCES RESEARCH COUNCIL

Zoe Dunford, JIC Press Office

Citation: SHANG,Y.; VENAIL,J. (2010) The molecular basis for venation patterning of pigmentation and its effect on pollinator attraction in flowers of Antirrhinum.

New Phytologist no. doi: 10.1111/j.1469-8137.2010.03498.x

Wild bee conservation

Scientists at the University of Cambridge UK, led by Professor William J Sutherland, have brought together scientific knowledge and experience about how to conserve wild bees around the world, in a free online resource Bee Conservation: evidence for the effects of interventions. The synopsis summarises evidence for 59 different actions you could take to help bees, from planting flowers in farmland to supporting beekeepers keeping indigenous species. Developed in partnership with an international group of bee experts, the synopsis will inform people taking action or spending money to benefit bees – from farmers to international NGOs – about what works and what does not. Evidence from 29 studies shows that providing nest boxes on agricultural land can benefit solitary bees. In several parts of the world solitary bees, including endangered species, will use nest boxes. Three studies show that numbers of nesting bees can double over three years with repeated nest box provision.

Bees can be problematic in places they are not indigenous, and there is some evidence about how to reduce the impacts of invasive nonindigenous bee species. For example a concerted effort to eradicate European bufftailed bumblebees from small patches of Japanese countryside increased numbers of the indigenous bumblebees, but did not remove the invaders altogether.

“Habitat preservation and the proper application and use of insecticides are the most important issues in bee conservation now,” says Peter Kwapong, of the International Stingless Bee Centre in Ghana, a member of the Advisory Board.

The bee synopsis is part of a project called Conservation Evidence, which aims to make conservation practice more science-based. The project has an open access journal where conservationists can document their experience and an online database of evidence. The series of synopses, of which Bee Conservation is the first, will cover major species groups and habitat types. Synopses are already being prepared for birds, butterflies, grassland and farmland. The Bee Conservation synopsis is available at: www.conservationevidence.com.

Lynn Dicks, Department of Zoology, University of Cambridge