Insect

Bee-friendly plants put to the test

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Honeybee on lavender (c) Science Photo Library

Researchers have used an experimental garden to put pollinator-friendly plants to the test.

The University of Sussex scientists counted the number of insects visiting the plants in their garden.

They say their findings show that insect-friendly plants are just as pretty, cheap and easy to grow as less pollinator-friendly varieties.

Their results are published in the Journal of Functional Ecology.

PhD student Mihail Garbuzov used 32 different varieties of popular garden plants. These included some nectar-rich and highly scented plants he thought would be attractive to insects and some that seemed to be less attractive.

While the small-scale study did not produce an exhaustive list of the best plants for pollinating insects, the team says the data has put a number on just how many more pollinators the right plants can attract.

Mr Garbuzov told the BBC: “Some of the best plants attracted approximately 100 times as many insects as the worst.

“And the plants that are attractive to insects are not more expensive, and they’re just as pretty.”

The researchers wrote in their paper that there was “great scope for making gardens and parks more insect friendly” by selecting the right plants.

Tips for insect-friendly gardening are already available from a variety of sources, but the researchers say they are largely based on “opinion and general experience”.

The aim of this study, said Prof Francis Ratnieks, from the University of Sussex, was to “put that advice on a firmer scientific footing, by gathering information about the actual number of insects visiting the flowers to collect nectar or pollen”.

Counting bees

Honeybee on a flower (c) Ethel M Villalobos
  • Bees have different colour-detection systems from humans, and can see the world in ultraviolet. This helps them to detect the flowers they pollinate and take nectar from.
  • Pollination is essential for agriculture, as well as the reproduction of non-food flowers and plants. According to the UN Food and Agriculture Organization, pollinators including bees, birds and bats are involved in more than a third of the world’s crop production.
  • Honeybees evolved to make honey as a food source for the colony. Selective breeding of European honeybees by humans has produced colonies that make excess honey for us to harvest.

The researchers gathered their data simply by visiting each of the patches of flowers every day over two summers and counting the number of insects on the flowers.

Their results did lead them to make some horticultural recommendations – they found that borage, lavender, marjoram and open-flower dahlias varieties were very good for insects.

The colourfully named bowles mauve everlasting wallflower was also very attractive to pollinators, while the least attractive flowering plant for insects was the very popular geranium.

Marjoram, the researchers say, was probably the best “all-rounder”, attracting honey bees, bumble bees, other bees, hover flies, and butterflies.

Borage was the best for honey bees and lavender and open-flowered dahlias were most attractive to bumblebees.

The team put a number of varieties of lavender to the test and found that highly bred hybrids, including some with novel colours – such as white or pink – that have been carefully bred into the plants proved the most attractive to insects.

Dr Nigel Raine, from Royal Holloway University of London, commented that with bee populations declining across the world, “we can all give bees a helping hand by planting the right flowers to give them the nectar and pollen they need”.

“This study highlights that it’s important for bee-friendly gardeners to choose what you plant with care,” he added.

“Gardeners and town planners should think carefully about the mixture of flowers they plant to ensure food is available for a wide range of bees and other important insect pollinators.

“It’s also important to cater for the needs of the rarer species and provide food at times when there might be fewer wild flowers in bloom.”

In another prior study, a team from the University of California San Diego used this ‘taste test’ to work out if bees are able to detect the scent of a flower. If the bee detects a floral scent, it will stick out its tongue.

Mosquito fossil found so well-preserved still has blood in its stomach.

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Scientists discover mosquito fossil so well-preserved that it still has blood in its stomach

  • The mosquito perished soon after feeding in the Middle Eocene and its body has been trapped in shale ever since
  • A team of international researchers used non-destructive mass spectrometry to create a chemical picture of the mosquito’s stomach contents
  • The find extends the fossil record of blood-feeding in this family of insects by 46 million years
Blood sucked by a mosquito that died 46 million years ago has been discovered by scientists.Researchers used a new technique to determine the nature of the animal’s last meal to prove that the insects have been feeding on blood all this time and could even have feasted on dinosaurs.The mosquito that was discovered perished soon after feeding in the Middle Eocene and its body has been trapped in shale ever since.

Researchers used a new technique to determine the nature of the mosquito's last meal

Researchers used a new technique to determine the nature of the mosquito’s last meal to prove that the insects have been feeding on blood all this time and could even have feasted on dinosaurs. The creature’s fossilised body (pictured) has been trapped in shale for 46 millions years

The animal died when the spectacular mountain ranges in Montana, where it was dug up, had just finished forming.

The ancient insect was so well-preserved because it had been trapped in shale – a type of mudstone in which organic remains decompose much more slowly – and the soft mud material that surrounded it compressed the creature’s body without distorting it.

The fine grain size of shale also preserves more details and the process of fossilisation is much like holding the fossil flat and pressing it like a book protects a dried flower.

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Paleobiologist Dr Dale Greenwalt, a researcher at the Smithsonian’s National History Museum, who led the study, used a state-of-the-art technology called non-destructive mass spectrometry to produce a detailed chemical picture of the mosquito’s stomach contents.

The findings show the insects have been feeding on blood for millions of years and around 14,000 living insect species including fleas, ticks and modern mosquitoes feed on blood today.

Although this feeding strategy appears to have evolved independently across a variety of animals, fossil evidence of this behaviour is extremely rare.

The find extends the fossil record of blood-feeding in this family of insects by 46 million years, according to Dr Ralph Harbach, a researcher at the Natural history Museum in London who was involved with the study.

Dr Dale Greenwalt used non-destructive mass spectrometry

Dr Dale Greenwalt used non-destructive mass spectrometry to produce a detailed chemical picture of the mosquito’s stomach contents. The findings show the insects have been feeding on blood for millions of years and around 14,000 living insect species including fleas, ticks and modern mosquitoes (pictured) feed on blood today

After finding high levels of iron in the fossilised insect’s abdomen, the researchers analysed the specimen and identified the source as haem – the protein in the blood responsible for the transport of oxygen.

Although large and fragile molecules such as DNA generally do not survive fossilisation, the mosquito proves certain complex organic molecules such as haem can be preserved.

It was one of two mosquitoes discovered in the shale deposits that reveal just how remarkably little the parasites have changed in the last 46 million years.

The new fossils – one female and the other male – are so detailed scientists were able to determine they represent two previously unknown species.

The female, named Culiseta lemniscata, had eaten the blood meal. The male has been named Culiseta kishenehn.

Their fossils contain details as intricate as wing veins, sexual organs, scales and hair-like structures on the wings.

Richard Attenborough in the film is pictured

Dr Greenwalt said it’s not surprising that it is the first discovery of its kind despite the misconception of dinosaur DNA recovery from mosquitoes preserved in amber popularised by Jurassic Park twenty years ago – Richard Attenborough in the film is pictured

Dr Greenwalt and colleagues, whose findings are published in Proceedings of the National Academy of Sciences, said the preservation of the fossil was ‘extremely improbable’.

‘The insect had to take a blood meal, be blown to the water’s surface and sink to the bottom of a pond or similar structure to be quickly embedded in fine sediment – all without disruption of its fragile distended blood-filled abdomen.’

He said it is not surprising that it is the first discovery of its kind despite the misconception of dinosaur DNA recovery from mosquitoes preserved in amber popularised by Jurassic Park twenty years ago.

‘The existence of this rare specimen extends the existence of blood-feeding behaviour in this family of insects 46 million years into the past,’ Dr Greenwalt said.

‘This is the only known fossil of a blood-engorged mosquito ever found and represents the first clear evidence that some organic molecules can be preserved in a fossil of this age.

‘We made the assumption that genetic material like DNA was not preserved. We didn’t even attempt to look at it because DNA degrades very quickly.

‘Without question there are probably other things contained in this fossil. We just don’t know what they might be,’ he added.