Aphrodisiac Virus Makes Plants Super-attractive To Bumblebees

Going viral is a good thing. Viral infections can help some plants attract more pollinators and produce more seeds, essentially boosting – rather than hurting – their evolutionary fitness, a new study has found.

Plants are known to emit volatile chemicals that deter herbivores or attract pollinators or seed dispersers. Some viruses can change those volatiles to attract insects, such as aphids, that damage plants but help transmit the virus between them.

Now, a team of researchers lead by John Carr from the University of Cambridge has shown in greenhouse experiments that a cucumber mosaic virus can change the types and amounts of chemicals emitted by an infected tomato plant, so that it attracts more bumblebees to pollinate it. As a result, the plants in their experiments produced more seeds.

Without pollination, the virus affected the plants negatively, decreasing their seed production, compared with non-infected plants. But when bumblebees were present, it had the opposite effect.

When the researchers then modelled what would happen under natural conditions, they found that such viruses could indeed enhance plant attractiveness to pollinators enough to make up for loss of fitness due to infection.

This means that the benefits of the virus could outweigh the drawbacks, allowing genes for susceptibility to persist in plant populations.

“To my knowledge, this is the first evidence that virus infection can make plants more attractive to pollinators,” says Carr.

The team can’t yet say how or why this process initially evolved. But they think that this is a case of mutualism, useful for all involved, including the bumblebees.

“Viruses reprogram plant metabolism and we can speculate that by chance this resulted in some beneficial changes for bees,” says Carr.

Infection protection

Although viruses can cause disease and crop losses in cultivated plants, “there is a growing realisation among plant virologists that in the wild, virus infection may be beneficial,” says Carr.

For example, his team has previously found that a protein made by the cucumber mosaic virus made infected Arabidopsis plants resistant to drought.

“The ability of cucumber mosaic virus to induce drought tolerance enhances the survival of its host and therefore of the virus itself during periods of environmental stress,” says Carr. “Indeed, under drought conditions, resistant plants may be at a disadvantage compared with infected ones.”

Carr thinks that this phenomenon could now be exploited to boost pollination of crops. “We can learn from the effects of the virus on pollinators,” he says. “Understanding how these volatile chemicals attract bees could be used to increase crop yields.”

John Walsh from the University of Warwick, UK, is intrigued by the findings. “This is the first evidence of this phenomenon. Such interactions, brought about by co-evolution between the three species – plant, insect and virus – are likely to be very important and need further research.”

The Meaning of Flower Colors

Did you know there is an entire branch of psychology devoted entirely to colors and their meanings?  Is it any wonder, then, that people have long associated different flower colors with different meanings and in fact they were once used as part of a code to get across one's message in a socially acceptable and discreet way.  Overall, the gift of flowers says, "I love you", "I appreciate you" or "I care how you feel", but there are many other messages that have traditionally been conveyed by the choice of flower colors.

Red is known as the color of passion, romance and love.  You certainly don't want to send red flowers, particularly roses to the wrong person or you could be sending a message you don't want to send.  If you aren't in love, don't send red roses choose pink instead.  Pink is the color of fun and love.  You can send pink flowers to a romantic interest or even to a family member or secretary without it being thought of as a romantic gesture.  Yellow is also a popular color choice because it symbolizes friendship and is a bright cheerful color that can put a smile on almost anyone's face.  Yellow is a great choice for a sick friend or anyone who needs a little pick-me-up.

Deeper colors can come across as sexy and mysterious.  The blood red rose or black rose are prime examples of this.  If you give or receive this color flower, seduction is in the air.  White flowers, in contrast, stand for purity and eternity and make a great choice for weddings and funerals alike.  A white flower could also be a sign of sincerity and pure intentions.  You might want to consider sending orange flowers to express happiness or joy such as for the birth of a child or to announce a trip or other exciting adventure.

While people have traditionally recognized the meaning of flower colors to symbolize a particular message or emotion, you should not feel restrained by this.  Today it is perfectly acceptable to choose flowers just because you like the way they look and the message you intend can clearly be written and included on the card that accompanies the flowers.  While you might still want to send red roses with caution, other flowers can safely be given to a variety of people for a variety of occasions and the meaning of flower colors will not be as important as the thoughtfulness of your gift.

Growing scented roses for summer

The eglantine roses I planted in the blossom wood are doing exactly what I wanted them to, and I am feeling rather good about it. They have had two summers to get their feet in and rise above the meadow grass, and with a little bulk their aromatic foliage is beginning to catch the breeze. I planted them on the windward side of the path quite deliberately so that their perfume would form an invisible tunnel of deliciousness. After dew or a shower of rain, you can walk into their influence, a delicate cloud that smells of green apples and early summer.

Rosa eglanteria – or the sweet briar, as it's otherwise known – was a component of Titania's bower in A Midsummer Night's Dream. You might at first confuse it with native dog rose, or Rosa canina. Though it will be easily as rangy when it's established, the added attraction of the essential oils in the foliage make it the superior plant in my book.

As soon as the foliage breaks in the spring it is performing, and though the perfume dims in the late summer as the foliage ages, by then its hips are providing for you.

The arching sprays of dog roses are at their most wonderful just now with bud in reserve and a smattering of flowers tumbling over the branches. Dog roses have a delightful simplicity which far outweighs their fleeting fortnight of flower, and their easy demeanour more than compensates for the fact that they are once-blooming. You simply have to think of them as you might a blossom tree and delight in their ability to root you in the moment.

They start early with the "Canary Bird", which pops bright at the start of May. I admit to never having grown it, favouring the slightly later Rosa x cantabrigiensis, which grows bigger in all directions, eventually to about 10ft. I use it on the margins of larger gardens to feather the way from ornamental garden to something wilder. The primrose yellow flowers cover the bush at cow parsley time, and they make excellent companions. The foliage is fine and ferny, and in autumn the branches are scattered with tiny dark-red hips. If I have the room, I'll team it with "Frühlingsgold" for the change in scale in the flowers. Soft in tone, its flowers age fast from gold to primrose. There is a humble quality about the shrub, and although you would never call it a dog rose, the ephemeral nature of the flowers retains a freshness.

At a more accommodating scale are the Scotch briar roses. You find Rosa spinosissima growing in coastal sand dunes, arching to 3ft or so and running into thickety colonies. On the Gower Peninsula in South Wales, it grows with bloody cranesbill and sea holly, the single creamy flowers studding branches massed with little thorns. The foliage is dark and ferny and, come the autumn, almost-black hips weight the branches. Grow it among silvery groundcovers and low lavenders to show these to best effect.

Resistant to sea breezes, never really troubled by pests or diseases, Scotch briars are toughies. "Dunwich Rose" is a handsome selection from Suffolk and perhaps the most floriferous, with lemon-yellow flowers. It will adapt to a range of soils. I also love "Single Cherry", with its pale reverse and fruity red flowers. Though not strictly a dog rose, "Stanwell Perpetual" is one of the few Scotch briars to repeat-flower. It is palest shell pink and semi-double, and I love its arching growth and resilience. "Double White" will grow a little bigger than most Scotch briars, forming a thicket of up to 5ft and making a fine wind break if you need it. Each little flower, not much more than an inch across, is perfectly formed, like a doll's house rose, and perfect in a sprig for a summer lapel. I plan to use it on the banks around my vegetable garden to give me some shelter from the westerlies. Planted deep, so that the root graft is covered, it will quickly sucker and run to form a thicket of delightfulness.

Insects find lifeline in the busiest of busy lizzies

Pop, pip, pop ... seedheads of Himalayan balsam are bursting in tiny explosions. The flower heads are chandeliers of red-green, glassy, pendants, which open into lipped, lobed, bulbous flowers like orchids from cerise to shell pink.

Each of these has a bee’s backside sticking out of it. When they’re pollinated and the petals crinkle and fall, the seedhead grenades are formed.

The first of these popped in Britain in 1839 when the plant was grown in gardens from seed collected in the Himalayas. Since then Himalayan balsam (Impatiens glandulifera), the busiest of busy lizzies, has colonised stream banks, river valleys and damp patches all over the country.

Sometimes this spread has been due to natural encroachment – the seeds can land seven metres away and are viable for two years. Sometimes it’s been caused by enthusiasts casting seeds.

This balsam has infiltrated popular culture under the names of policeman’s helmet, ornamental jewelweed, poor man’s orchid, stinky-pops, kiss-me-on-the-mountain, bee bums and Mr Noisy’s exploding plant. Yet it splits opinion.

Some – including the government – find it a nightmare weed, an alien invader with gaudy flowers and a noxious pong, a thug bullying native plants and swamping habitats. Because it is shade tolerant it dominates other plants and, being an annual, exposes stream banks to erosion when it dies back in winter. This brings out armies of volunteers, and sometimes the army, on balsam bashing operations.

Others appreciate its exotic splash of colour and scent and the nectar it provides, not only in its flowers but from glands under the leaf stalks. A vast number of insects, particularly bumblebees at the moment, feed on it when there are few other flowers about, and will do so until later in autumn when the frosts hit.

Where the climate gets warmer and wetter, plants like Himalayan balsam will thrive. Perhaps the tide of opinion is becoming more accepting of the colonists. The Himalayan balsam patch I’m watching is certainly growing rapidly and is full of life, unlike the thickets of buddleia, which are also garden escapes and have been around long enough to be prized as butterfly plants but are largely as empty as abandoned nightclubs this year. Hopefully Mr Noisy’s “outlaw” will give sanctuary to insects being wiped out in the rest of the landscape.