Termites (not fairies) cause plant circles in African deserts

TermiteRingsNot quite ants, bees or wasps, but still pretty cool.

In arid, sandy soils ranging from Angola to South Africa, “fairy rings” of perennial grass species dot the landscape. These rings have inspired ecological and mythological speculation about their origins.  Norbert Jürgens of the University of Hamburg in Germany has worked on these rings for years and has determined that they are the result of the sand termite (Psammotermes allocerus).

Termites create these rings after eating the roots of grass. Their chomping results in a bald patch that becomes the ring center. The soil in the center of that patch stays damper than neighbouring areas. The circles’ bull’s eye then sustains both the moisture-loving termites and a belt of grasses around its edge.

I’ve seen rings like these in New Zealand grasslands, though was taught somewhere, sometime, that they were fungus related. I’ll check for termites next time I’m in a field with some of these.

More information here.

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Plants drug honey bees with caffeine.

honeybee-flower1I’m sure that caffeine has many positive effects for me. And it turns out that the little brains of honey bees are influenced as well.

Some plants are effectively drugging the bees with caffeine. It was thought that caffeine was an anti-herbivore response. But it modifies bee brains as well.

In a long-term memory experiment caffeinated bees remembered an odour better than their non-caffeinated sisters. Three times as many bees on caffeine stuck out their tongues for a reward 24 hours after training, compared to their decaffeinated sisters, and twice as many recalling it 72 hours later.  Caffeine thus appears to help the bees learn.

Plants are thought likely to benefit because the bees remember where the tasty reward is and come back for more (thus more pollination).

Caffeine modifies how bee brain neurons respond to learning and memory tasks. It appears to result in a stronger reaction of bee-brain cells to sensory input. These stronger reactions in term causes a long-term potentiation, which is a major mechanism resulting in memory formation.

I’m going to keep drinking my coffee…

The full article is available in Science Magazine. A good additional reports is available here at NBC news.

Bees keep elephants from stealing crops

In Kenya increasing elephant populations have been widely praised as a conservation success story. But this success represents a problem too. Elephants raid crops. Thorny fences represent little obstacle to these large marauders, but they don’t want to mess with an angry bee…

Dr Lucy King and her group from the University of Oxford used a novel beehive fence deployed in 62 communally run farms in Kenya. Beehive  fences semi-surrounded the outer boundaries of seventeen farms. They compared elephant farm invasion events with these and to seventeen neighbouring farms whose boundaries were ‘protected’ only by thorn bush barriers. Their results demonstrate that beehive fences are more effective than thorn bush barriers at deterring elephants. The bees may have a role to play in alleviating farmer–elephant conflict. The bees also provide pollination and produce honey.

A Sagalla beehive fence. Photo from http://www.elephantsandbees.com/

The elephants even have a alarm call specific to these bees!

The Elephants and Bees Research Project is one of Save the Elephants’ innovative programs designed to explore the natural world for solutions to human-elephant conflict.  More information on Dr King’s project can be found here, including publications and more pictures.

Watch out below: wasps battle ants by dropping them

ImageOne of the most successful invasive species is the common wasp, Vespula vulgaris. Dr Julien Grangier recently demonstrated how foragers of this wasp have adopted previously unknown interference behaviour when competing for food with native ants. Picking their opponents up in their mandibles, flying backward and dropping them some distance away from the disputed resource, wasps were shown to efficiently deal with a yet aggressive competitor. The wasps modulate this behaviour according to various circumstances including the abundance of ants. In this second paper we further discuss the nature and functioning of this unusual strategy. We first highlight the questions this interaction raises regarding the competitive advantages offered by asymmetries in body size and flight ability. Then, we argue that this study system illustrates the important role of behavioural plasticity in biological invasions: not only in the success of invaders but also in the ability of native species to coexist with these invaders.

Image

Our initial paper describing this behaviour was published in BIOLOGY LETTERS. Associated with this article was a video published in YouTube, which has been viewed over 60,000 times. We were invited to publish this paper in COMMUNICATIVE & INTEGRATIVE BIOLOGY in 2012. The work was covered in the journal Science and the National Geographic.

Nematodes in New Zealand native ants

Diploscapter formicidae sp. n. (Rhabditida: Diploscapteridae)

Ever dissected an ant and found it to be jam packed with will little worms? Evan Brenton-Rule, Julien Grangier  and Monica Gruber have. The article on nematode infections in native ants is out “on-line early” in Nematology. With a Landcare Research Ltd scientist (Dr Zeng Qi Zhao) they describe a new species of nematode commonly infecting the native ant Prolasius advenus. While females of this nematode were abundant, we have yet to find a male, which indicates males may be absent or rare in this species.

The full article can be found, with some amazing microscopy images, on line in the journal NEMATOLOGY.

Honey-bees found to have bite that stuns

Honey-bees are known for their sting, but scientists have now discovered they can also bite. Bees resort to biting when faced with pests, such as parasitic mites, that are too small to sting. Close study of the biting behaviour has revealed that they secrete a chemical in their bite that stuns pests so they are easier to eject from a colony. Tests suggest the chemical could also have a role in human medicine, as a local anaesthetic. Bees were thought to use their mandibles to groom rather than bite The pests that honey-bees bite include varroa mites as well as wax moth larvae. The varroa mite is endemic throughout both feral and cultivated honey-bee colonies.  The knock-out effect of the chemical secreted in the honey-bee bite, known as 2-heptanone, was discovered as Dr Papachristoforou and colleagues observed bees dealing with pests.  Early tests suggest 2-heptanone may also find a role in humans as a local anaesthetic. It could be an alternative to well established treatments such as lidocaine that can provoke allergenic reactions in some people. The researchers published their results in the journal Plos One.

“The potential implications of this new research for honey-bees and their interactions with varroa mites and wax moth larvae will need to be looked at in more detail, but the initial results look really interesting,” said Giles Budge, senior researcher with the UK’s National Bee Unit. “I think it is amazing that despite all the years of intensive study there are still massive discoveries to be made about fundamental honey-bee physiology such as the ability to paralyse small insects and mites,” he said.

Dr Papachristoforou, said the good news about the research was that bees would not inflict any damage on humans if they bit them. “Humans cannot be bitten by bees,” he said. “They have such small mandibles they can only use them against larvae and mites.”

See the full published article for free in the journal  PLoS One. The full article that I swiped this text from was from here at the BBC.