Petal ‘landing lights’ help bumblebees

Gardeners can help maintain bumblebee populations by growing flowers equipped with “landing lights”, new research suggests. A study found that the insects favour snapdragons with striped petals.

Scientists believe the patterns perform a similar function to runway landing lights used by aircraft.

“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 Cathie Martin, from the John Innes Centre in Norwich.

“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 field research was carried out by students who observed bumblebees foraging among different snapdragon strains over a number of successive summers.

They found that striped flowers were visited significantly more frequently than those with plain white or pink petals.

The bees were also more attracted to plants with red flowers.

Bumblebees are vital pollinators for snapdragons because only their heavy bodies can open the closed flowers.

A team of New Zealand scientists also took part in the research, published in the journal New Phytologist.

They looked into how stripy patterns are formed along the petal veins of the common snapdragon.

“Complex colour patterns such as spots and stripes are common in nature but the way they are formed is poorly understood,” said 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.”