Conducting behaviour

A study recently published in Proceedings of the Royal Society B suggests that honey bees may communicate using the electric fields that build up on their wings when they fly . The authors showed that electric fields change the position of the bees’ antennae. This in turn affects the sensory Johnstone’s organ the base of the antennae, which sends signals to the brain. Tests were conducted that showed honey bees learned a carbohydrate rich reward was present when they detected a specific electric field. This is another, fascinating way in which honey bees may be able to communicate with each other… or aid in communication such as the waggle dance. 

 

Interestingly, another study, recently published in Science, suggests that bumblebees can distinguish between the electric fields of flowers recently visited and those which are unvisited and have untapped reservoirs of nectar. In lab experimentation bees were able to distinguish between artificial flowers with two potential electric fields: one gave a sweet reward and the other gave a bitter reward. If bumblebees are able to do this in nature it would mean more efficient foraging behaviour.

 

 

 

 

 

 

Advertisements

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.

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.

Caterpillar Bodyguards

The interaction of parasitoid wasps with their hosts are often fascinatingly macabre. The interaction between the wasp Glyptapanteles sp.and its host, Thyrinteina leucocerae is no exception.

 

Adult female wasps oviposit directly into caterpillars of the moth. These parasitised caterpillars continue to develop along with up to 80 parasitoid larvae inside them. When the caterpillar reaches the 4th or 5th instar the parasitoid larvae tunnel out of the host to pupate. The larvae spin cocoons close to the caterpillar.

 

This is where things become interesting. The host then undergoes a series of behavioural changes. It ceases to feed and remains stationary near the cocoons. However, if the cocoons are approached by a potential disturbing agent, the caterpillar violently swings its head, apparently attempting to dislodge the disturbing agent.

 

Grosman et al compared the behaviour of parasitised and unparasitised caterpillars and the relative survival of wasps. They found that unparasitised individuals ignored wasp cocoons, as well as potential threats to the cocoons. They also found that removing parasitised caterpillars doubled the death rates of the wasps.

 

The authors dissected caterpillars from which parasitoids had egressed and found 1-2 active parasitoid larvae that had remained in the host. They hypothesise that the remaining larvae are responsible for the changes in host behaviour and that they represent the cost of host manipulation – some offspring are sacrificed for the survival of their kin.

 

The full paper can be found here: http://www.plosone.org/article/info:doi/10.1371/journal.pone.0002276Image

Reverse brain aging in honeybees

Researchers from Arizona State University, observed improvements in brain functions among older bees that turn their attention back to nursing the larvae. When the young bees, responsible for brood care, were removed from the hive, some of the older foragers assumed their work. Bees that returned to caring the larvae showed an increased ability to learn and less signs of aging normally shown by older bees (worn wings, hairless bodies, and more importantly, loss of brain function). The scientists also detected proteomic changes in the brains of the bees that had learned new things. One of these proteins, which is also found in humans is known to protect against dementia, including Alzheimer’s disease. The results presented highlight the importance of psychological balance in the elderly and indicate that changing how you deal with your surroundings can help our brains stay younger.

This article can be found here. More information on Dr. Amdam’s lab work on bees can be found here.