‘Jewel of nature’: scientists fight to save a glittering green bee after the summer fires



Remko Leijs, Author provided

Katja Hogendoorn, University of Adelaide; Remko Leijs, Flinders University, and Richard V Glatz, University of Adelaide

This article is a preview of Flora, Fauna, Fire, a multimedia project launching on Monday July 13. The project tracks the recovery of Australia’s native plants and animals after last summer’s bushfire tragedy. Sign up to The Conversation’s newsletter for updates.


The green carpenter bee (Xylocopa aerata) is an iconic, beautiful native species described as a “jewel of nature” for its metallic green and gold colouring. Carpenter bees are so named because they excavate their own nests in wood, as opposed to using existing holes.

With a body length of about 2 centimetres, it is among the largest native bees in southern Australia. While not used in honey farming, it is an important pollinator for several species of Australian native plants.

Last summer’s catastrophic bushfires significantly increased the risk of local extinctions of this magnificent species. We have studied the green carpenter bee for decades. For example, after the 2007 fires on Kangaroo Island, we bolstered the remaining population by providing nesting materials.

To see our efforts – and more importantly, most of the habitat these bees rely on – destroyed by the 2020 fire was utterly devastating.

Much of Kangaroo Island was incinerated by the summer bushfires.
Daniel Mariuz/AAP

A crucial pollinator on the brink

The green carpenter bee is a buzz-pollinating species. Buzz pollinators are specialist bees that vibrate the pollen out of the flowers of buzz-pollinated plants.

Many native plants, such as guinea flowers, velvet bushes, Senna, fringe, chocolate and flax lilies, rely completely on buzz-pollinating bees for seed production. Introduced honey bees do not pollinate these plants.




Read more:
Our field cameras melted in the bushfires. When we opened them, the results were startling


The green carpenter bee went extinct on mainland South Australia in 1906 and in Victoria in 1938. It still occurs on the relatively uncleared western half of Kangaroo Island in South Australia, in conservation areas around Sydney, and in the Great Dividing Range in New South Wales.

Local extinctions were probably due to habitat clearing and large, intense bushfires. The last time the green carpenter bee was seen in Victoria was early December 1938 in the Grampians, which burnt completely during the Black Friday fires of January 1939.

There are several reasons green carpenter bees are vulnerable to fire, including:

  • the species uses dead wood for nesting, which burns easily
  • if the nest burns before the offspring matures in late summer, the adult female might fly away but won’t live long enough to reproduce again, and
  • the bees need floral resources throughout the year.
A male green carpenter bee.
Remko Leijs, Author provided

Nowhere to nest

The bees mainly dig their nests in two types of soft wood: dry flowering stalks of grass trees and, crucially important, large dead Banksia trunks. The availability of both nesting materials is intricately connected with fire.

Green carpenter bees sometimes nest n the dried flowering stalks of grass trees, also known as Xanthorrhoea.
Remko Leijs, Author provided

Grass trees flower prolifically after fire, but the dry stalks are only abundant between two and five years after fire. Banksia species don’t survive fire, and need to grow for at least 30 years to become large enough for the bees to use.

Bees nesting in an artificial stalk.
Remko Leijs, Author provided

With increasingly frequent and intense fires, there’s not enough time for Banksia trunks to grow big enough, before they’re wiped out by the next fire.

A helping hand after the 2007 fires

In 2007, Flinders Chase National Park on Kangaroo Island burnt almost entirely.

An artificial stalk nesting site installed in a Xanthorrea.
Remko Leijs, Author provided

However, in long-unburnt areas adjacent to the park, carpenter bee nests were still present. From there, they colonised the many dry grass tree stalks that resulted from the fire in the park.

In 2012, most flowering stalks had decayed. In an attempt to bolster population size, we successfully developed artificial nesting stalks to tide the bees over until new Banksia, suitable for nesting, would become available.

Since then, each year we’ve placed artificial nesting stalks in fire-affected areas where the bee still occurred. Almost 300 female carpenter bees have successfully used our stalks to raise their offspring.

Then came the January 2020 fires

At the time of the 2020 fires on Kangaroo Island, there were more than 150 nests containing mature brood in the stalks we had provided.

We’d placed these in 12 sites in and around Flinders Chase National Park, to spread risk – to no avail, as they all burnt.

We were horrified to see the intensity and speed of the fire that turned our efforts to ash, along with most of the remnant, long (more than 60 years) unburnt Banksia habitat the bees rely on. In New South Wales, much of the species’ natural range was also burnt.

The yellow dots represent known green carpenter bee nests. In red: the area burnt in 2020. Only a subset of the remaining green and yellow patches still have the right vegetation for the green carpenter bee.
Nature Maps SA/Remko Leijs, Author provided

What’s next for the green carpenter bee?

To fully appreciate the impact, we need to survey the remaining long unburnt areas on Kangaroo Island and in NSW.

Encouragingly, we have already found a few natural nests on Kangaroo Island, but the remaining suitable areas are small and isolated, and densities are likely to be low.

With funds raised through the Australian Entomological Society and the Wheen Bee Foundation, and with help of the Kingscote Men’s Shed, we are making new nesting stalks.

The Kingscote Men’s Shed on Kangaroo Island is helping build new nesting stalks.
Remko Leijs, Author provided

With permission of landholders, we’ll place these new stalks in areas with good floral support, to enhance reproduction and help the bees disperse into conservation areas once suitable.

As we have learnt, success is not guaranteed. Extensive and repeated bush fires, combined with asset protection and fuel reduction burns, are making longtime unburnt habitat increasingly rare. It is this lack of old, continuous, unburnt forest that severely threatens the green carpenter bees’ existence.

The future of fire-vulnerable biodiversity

The carpenter bee is not the only species facing this problem. Many Australian plants and animals are not resilient to high frequency fires, no matter their intensity or time of year.

The ecological importance of longtime unburnt forest needs urgent recognition, as increased fire frequency – both of natural and “managed” fires – is likely to drive a suite of species to extinction.

For Kangaroo Island, this could include several small mammals, glossy black cockatoos, and a range of invertebrate species, including the green carpenter bees.

Given the expected increase in fire frequency and intensity associated with global heating, it’s time we recognise fire-vulnerable species as a category that requires urgent habitat protection.




Read more:
After last summer’s fires, the bell tolls for Australia’s endangered mountain bells


The Conversation


Katja Hogendoorn, University of Adelaide; Remko Leijs, Researcher, Flinders University, and Richard V Glatz, Associate research scientist, University of Adelaide

This article is republished from The Conversation under a Creative Commons license. Read the original article.

One, then some: how to count like a bee


Scarlett Howard, Deakin University and Adrian Dyer, RMIT University

If you were a honeybee, how would you choose where to find flowers? Imagine your first flight out of the hive searching for food. What would you do if you saw flower patches with one flower, or three, or twelve, or twenty?

Our new study, published in the Journal of Experimental Biology, tested honeybees on exactly this question. We wanted to understand how honeybees choose where to forage in environments like greenhouses where our food is pollinated, in local parks, or in our own backyards.

Specifically, our research looked at whether honeybees with no specific numerical training could choose a flower patch based on the quantity of flowers it had.

We found the bees could tell the difference between groups of 1 vs 4 flowers – but not between, say, 4 vs 5. Basically, they couldn’t differentiate between groups of 2 or more flowers.

A honeybee pollinating a strawberry plant flower in a greenhouse.
Adrian Dyer/RMIT University

A mathematical matter of life and death

The ability to tell the difference between two quantities can mean life or death for an animal. “Quantity discrimination” can be vital for survival in tasks including:

  • resource comparison: choosing a larger quantity of food

  • aggressive interactions: choosing to avoid conflicts with larger groups of individuals, and

  • avoiding predators: choosing to stay with a larger group of animals of the same species to reduce your chance of being eaten.

We are gaining a better understanding of quantity discrimination across the animal kingdom. Primates and other mammals, amphibians, reptiles, birds and fish all display some form of quantity discrimination in day-to-day tasks. For example, fish use quantity discrimination to stay in larger groups to reduce the chance of being eaten by a predator.

However, little is known about spontaneous number choices by insects.




Read more:
We taught bees a simple number language – and they got it


How do bees choose where to forage?

Honeybees assess the available flowers based on several factors, including scent, colour, shape and size.

Backyard flowers; which patch to choose if you were a bee?
Adrian Dyer/RMIT University

Honeybees typically visit around 150 individual flowers per flight from the hive to collect resources such as nectar or pollen. For a honeybee, a high quantity of flowers in a single area would mean less energy exertion than having to fly to many flower patches with less flowers.

Using different numbers of artificial flowers, we wanted to test whether individual honeybees could discriminate between a range of quantities, and how they might determine the quality of a flower patch.

Our honeybees were shown pairs of flower quantities ranging from easier number comparisons (such as 1 flower vs 12 flowers) to more challenging scenarios (such as 4 flowers vs 5 flowers).

The experimental set-up (left) and the quantity comparisons (right). Honeybees succeeded at spontaneously discriminating between 1 vs 12, 1 vs 4, and 1 vs 3 flowers, but no other comparisons. The honeybees were trained to associate single yellow dots with sugar water before being shown quantity comparisons.
Scarlett Howard

Interestingly, despite previous findings that trained honeybees can discriminate between challenging quantities and can also learn to add and subtract, the bees performed poorly in our spontaneous number task.

We found they were only able to discriminate between 1 vs 3, 1 vs 4, and 1 vs 12 flowers – wherein they preferred the larger quantity. When 1 flower was an option they succeeded, but confused any comparisons between groups of 2 flowers or more.

This result suggests flower patch choice based on numerical-type cues is difficult for honeybees. And this has implications for how flower displays are interpreted.

A honeybee flies towards three flowers.
Scarlett Howard

With today being World Bee Day, why not take the opportunity to discover what bees are doing in gardens near you. Chances are they’re going to any flower patch with more than one flower, rather than paying much attention to absolute numbers.




Read more:
Bees learn better when they can explore. Humans might work the same way


The Conversation


Scarlett Howard, Postdoctoral research fellow, Deakin University and Adrian Dyer, Associate Professor, RMIT University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Aussie scientists need your help keeping track of bees (please)



The Asian honey bee (Apis cerana) has been found in Cairns. It’s just one of the introduced bees buzzing under the radar.
Tobias Smith, Author provided

Manu Saunders, University of New England; Callum McKercher, University of New England; Mark Hall, Western Sydney University; Tanya Latty, University of Sydney, and Tobias Smith, The University of Queensland

Bees get a lot of good press. They pollinate our crops and in some cases, make delicious honey. But bees around the world face serious threats, and the public can help protect them.

Of more than 20,400 known bee species in the world, about 1,650 are native to Australia. But not all bees found in Australia are native. A few species have been introduced: some on purpose and others secretly hitchhiking, usually through international trade routes.

As bee researchers, we’ve all experienced seeing a beautiful, fuzzy striped bee buzzing about our gardens, only to realise it’s an exotic species far from home.




Read more:
The farmer wants a hive: inside the world of renting bees


We need the public’s help to identify the bees in Australian backyards. There’s a good chance some are not native, but are unwanted exotic species. Identifying new intruders before they become established will help protect our native species.

The European honey bee (Apis mellifera) fuels a valuable honey industry and contributes to agricultural pollination. Other introduced species are far less welcome.
Tobias Smith

Exotic bees in Australia

The European honey bee (Apis mellifera) is the best-known introduced species, first brought to Australia in the early 1800s. It is now well-established throughout the country, with profitable industries built around managed populations.

Other invasive species in Australia are less well known (or loved). The European bumblebee (Bombus terrestris) is present in high numbers in Tasmania, but isn’t thought to be established on mainland Australia.

This bumblebee has caused major harm to native bees in South America, competing for resources and spreading disease.

In northern Queensland, the Asian honey bee (Apis cerana) is established around Cairns and Mareeba, from a single incursion in 2007. The original founding colony is thought to have been a stowaway on a boat that sailed to Cairns from somewhere in southeast Asia or the Pacific, where this bee is widespread.

New Asian honey bee incursions at Australian ports occur almost annually, most recently in Townsville and Melbourne. But swift biosecurity responses have so far stopped them becoming established.

The European bumble bee (Bombus terrestris) lives in large numbers in Tasmania, but is not established on the mainland.
Tobias Smith, Author provided

Why should we care?

Most insects can spread and establish breeding populations before anyone notices them, so it’s important we pay attention to these small intruders.

Introduced species can bring new parasites or diseases into the country that may harm native insects – including our stingless bees that are so vital to crop pollination – or affect the valuable European honey bee industry.

While bumblebees may help commercial pollination in a handful of Australian crops, they and other introduced species can also compete with native species for resources, or spread weeds.

Most resources go to monitoring invasive species with a more dramatic and understood effect on agriculture and the environment. Bees sneak under the radar – but we’re still curious.

Take the African carder bee (Pseudoanthidium repetitum), which arrived in Australia in the early 2000s. Thanks to citizen scientists, we know they are spreading rapidly. In 2014, they were the third most common bee species found in a survey of Sydney community gardens.

An African carder bee spotted in Lismore. They are the third most common bee species in Sydney community gardens.
Tobias Smith, Author provided

Just recently, we found two invasive African carder bees in a backyard in Armidale in northern New South Wales while testing out a new insect monitoring method. There are no confirmed records of this invasive bee in Armidale, although we have seen a few around town since 2017.




Read more:
Bees: how important are they and what would happen if they went extinct?


Although it’s usually exciting to find a new record for a native species, finding an exotic bee where it’s not supposed to be is worrying. How long have they been there, and how many others are there?

The European bumble bee was recently sighted to global biodiversity.

You don’t have to be totally sure what kind of bee you’ve spotted. Just snap some pictures and upload it to a citizen scientist app like iNaturalist with the date and location.
Jean and Fred/Flickr, CC BY

Will you help us keep track?

Anyone can help keep track of potential new invasive species, simply by learning more about the insects in your local area and sharing observations on citizen science platforms such as iNaturalist, or through targeted projects like the African carder bee monitoring project.

You don’t need to be sure exactly what species you’ve seen. Uploading some clear, high-resolution photos, along with the date and location of your observation, will help naturalists and researchers identify it.




Read more:
Wasps, aphids and ants: the other honey makers


You can also participate in events such as the twice-yearly Wild Pollinator Count or local Bioblitzes.

Your efforts can help us detect emerging threats, and add to our records of both native and non-native bees (and other species). Plus it’s a great excuse to get outdoors and learn more about the insect life in your area.


This article was co-written with Karen Retra.The Conversation

Manu Saunders, Research fellow, University of New England; Callum McKercher, PhD Student, University of New England; Mark Hall, Research fellow, Western Sydney University; Tanya Latty, Associate professor, University of Sydney, and Tobias Smith, Ecologist, bee researcher and stingless bee keeper, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bees seeking blood, sweat and tears is more common than you think



File 20190412 76837 1czhl8p.jpg?ixlib=rb 1.1
Known sweat-collecting stingless bees, Tetragonula sp., from the bee family Apidae.
Tobias Smith, Author provided

Manu Saunders, University of New England and Tobias Smith, The University of Queensland

The recent story of four live bees pulled from inside a woman’s eye quickly grabbed people’s attention. News reports claimed the bees were “sweat bees”, the common name for species in the bee family Halictidae.

There are some contradictory and unlikely statements in the many news reports covering this story, so it’s hard to know what actually happened. The images accompanying many reports, which some reporters captioned as the live sweat bees in the Taiwanese woman’s eye, are actually uncredited images from a completely unrelated story – this report by Hans Bänzinger of a stingless bee species (Lisotrigona cacciae) collecting tears from his eye in Thailand.


The Guardian/ Bees (Hymenoptera: Apidae) That Drink Human Tears, in Journal of the Kansas Entomological Society.

All in all, we would consider it extremely unlikely for multiple adult insects to survive inside a human eye for very long. Most halictid bees are too large to get trapped in your eye unnoticed. Female sweat bees also have stingers so you would definitely know straight away!

But whether this story is accurate or not, there are bees who would happily feast on human tears – and blood, sweat and even dead animals. Flower-loving insects like bees and butterflies often seek out other food sources that are at odds with their pretty public image.




Read more:
Can bees do maths? Yes – new research shows they can add and subtract


Un-bee-lievable

So why would bees hang around someone’s eye in the first place? It’s a bit of a myth that all bees only collect pollen and nectar for food. There are bee species all over the world that also feed on the bodily fluids of living and dead animals, including animal honeydew, blood, dead meat, dung, sweat, faeces, urine and tears. This is a source of important nutrients they can’t get from flowers, like sodium, or protein and sugar when floral resources are scarce.




Read more:
Wasps, aphids and ants: the other honey makers


The term “sweat bee” is used colloquially for bees that ingest human sweat as a nutritional resource.

Many people think the term only refers to bees in the Halictidae family. But not all halictid bee species are known to collect sweat, while many species in the Apidae family, particularly stingless bees, are common sweat-collectors in tropical areas around the world. Swarms of sweat-seeking stingless bees can be a nuisance to sweaty humans in tropical places.

And it’s not just sweat; stingless bees have quite diverse tastes and collect many non-floral resources. There are also a few neotropical Trigona species that collect animal tissue as their main protein source, instead of pollen. These species collect floral nectar and make honey, like other stingless bees, but predominantly scavenge on carrion (they are technically know as obligate necrophages).

Vulture bees feed on rotting meat rather than pollen or nectar.
Wikipedia/José Reynaldo da Fonseca, CC BY-SA

Regardless of taxonomy, bees that are attracted to sweat often use other bodily fluids too, like tears. Tear-feeding is such a common behaviour among insects, it has an official name: lachryphagy. Some stingless bees from south Asia, such as the Lisotrigona species mentioned above, are well-known lachryphagous insects, often seen congregating in groups around animal eyes (including humans) to harvest fluids. They don’t harm the animal in the process, although their activity might be a nuisance to some.

In South America, Centris bees are large, solitary apid bees, in the same family as stingless bees and honey bees. These bees are often observed drinking tears from animal eyes; published observations include interactions with caimans and turtles.

Bees aren’t the only insects that regularly drink from animal eyes. Our world-famous hand gesture, the Aussie salute, is designed to deter the common bush flies (Musca species) that hang around our faces on hot days, looking for a quick drink of sweat, saliva or tears. These flies are also commonly seen clustered around livestock eyes on farms.

The feeding habits of butterflies would shock many people who think they are dainty, angelic flower-frequenting creatures. Butterflies are common feeders on dung, carrion, mud and various other secretions, including animal tears. Moths are also well-known nocturnal feeders on animal tears, even while they are sleeping.

Julia butterflies drinking the tears of Arrau turtles in Ecuador.
Wikimedia/amalavida.tv, CC BY-SA

Although most of us wouldn’t like the idea of an insect drinking out of our eyelid, this isn’t the stuff of nightmares. It’s just another fascinating, but little-known, story of how animals interact with each other. From a bee’s perspective, an animal’s eye is just another food source.




Read more:
Catch the buzz: how a tropical holiday led us to find the world’s biggest bee


It produces secretions that provide important nutrients, just like a flower produces nectar and pollen. Although entomologists know this behaviour occurs, we still don’t fully understand how common it is, or how reliant pollinating insects are on different animals in their local environment.

But, while tear-collecting behaviour is normal for many insects, the odds of live bees crawling inside your eye to live are extremely low.The Conversation

Manu Saunders, Research fellow, University of New England and Tobias Smith, Ecologist, bee researcher and stingless bee keeper, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Catch the buzz: how a tropical holiday led us to find the world’s biggest bee



File 20190221 148523 qptvp2.jpg?ixlib=rb 1.1
Eli Wyman with the elusive Wallace’s Giant Bee.
Clay Bolt, Author provided

Simon KA Robson, University of Sydney

Many people on a tropical island getaway might take a jungle hike, or learn about the local wildlife. My colleagues and I went one better: we tracked down the world’s biggest bee species, which hadn’t been spotted for decades, while on holiday in Indonesia’s North Molucca islands.

Wallace’s giant bee, Megachile pluto, is fascinating for many reasons. It’s the largest of all known living bees, with a body length about that of a human thumb and a wingspan of more than 6cm. What’s more, its last confirmed sighting in the field was in 1981. After numerous efforts to rediscover it, it was unclear whether the species still remained in the wild.

Beenormous: M. pluto is roughly four times the size of a European honeybee.
Clay Bolt, Author provided

The bee also has a special place in scientific history. It was first collected by the British naturalist and explorer Alfred Russel Wallace in 1859, as part of his work in the Malay Archipelago. He described the female bee as “a large black wasp-like insect, with immense jaws like a stag-beetle”.

Wallace not only independently derived the theory of natural selection as an explanation for evolution alongside Charles Darwin, but his detailed studies of the distribution of animals gave rise to the famous Wallace Line, a boundary that splits Australia and Asia and helps to explain the distribution patterns of many plants and animals.




Read more:
Wallacea: a living laboratory of evolution


Holiday plans

How did four biologists from across the globe, two from Australia (myself and Glen Chilton) and two from the United States (Eli Wyman and Clay Bolt), end up on this journey?

My involvement started at the prompting of Glen, who although specialising in ornithology and writing was interested in both Wallace and the rediscovery of potentially extinct species. He became aware of the existence of the world’s largest bee, and after two years of cajoling I agreed that searching for the bee would represent an excellent holiday.

During the planning for our trip, we became aware that Eli and Clay were also, independently, planning to travel to the Moluccas to search for M. pluto. After a brief Skype call we decided it made sense to join forces and collaborate. So despite our two duos never having met in person, we were a team heading out into the field.

And what a great team it was: Eli’s expertise in all things bee-related; Clay’s fantastic photographic skills; Glen’s enthusiasm and knowledge of Wallace; and my own fascination with the evolution of insect behaviour.

On the ground

We converged on the island of Ternate and began our search across the North Molucca islands for termite mounds containing bee-sized holes, helped by two excellent local guides, Ekawati Ka’aba and Iswan Maujad.

M. pluto is a solitary bee species that forms communal nests inside termite mounds, using its mandibles to collect and apply tree resin to the inner walls of its nest. So we knew what to look out for.

After five fruitless days of searching termite mounds, we were about to call it quits and head for a late lunch when we spotted another mound near the edge of a path.

Inspection with a torch and binoculars revealed a hole that looked promising. Clay scaled the tree and reported that the hole looked to be lined with resin – very exciting. Our guides constructed a platform from branches, we inspected the hole in more detail, and there she was. Cue intense excitement and cries of jubilation as we all rushed to peer inside and catch a glimpse.

Now that we had the bee, we had to be able to prove it, so we put away our iPhone cameras in favour of better-quality (but riskier: the bee might escape!) footage with more professional photographic and video equipment. We gently coaxed her out of her nest and into a small flight chamber, and then eventually Clay got the magic shot, where we released the bee back onto her nest and photographed her at the entrance to her home. Mission accomplished.

Capturing the evidence.
Simon Robson, Author provided

Confirming that the world’s largest bee species is still alive is an enticing development for ecologists. We can learn a lot about the ecology, behaviour and ecological significance of this giant. Amid a global decline in many insects, it’s wonderful to discover this special species is still surviving.




Read more:
Ten years after the crisis, what is happening to the world’s bees?


We also hope our discovery will galvanise conservation movements in Indonesia, and we were inspired by the reception our journey met with many people in the conservation and forestry fields of the North Molucca islands.

We would love more work to be done to assess the bee’s current conservation status. Plans to produce a documentary about Wallace and the rediscovery of this bee are underway, and we hope that its rediscovery provides further impetus to conservation efforts generally.

Not a bad outcome for a holiday!The Conversation

Simon KA Robson, Honorary Professor, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Can bees do maths? Yes – new research shows they can add and subtract



File 20181211 76962 cfh85r.jpg?ixlib=rb 1.1
Can we have a count of all the honeycomb cells please?
from www.shutterstock.com

Scarlett Howard, RMIT University; Adrian Dyer, RMIT University, and Jair Garcia, RMIT University

The humble honeybee can use symbols to perform basic maths including addition and subtraction, shows new research published today in the journal Science Advances.

Bee have miniature brains – but they can learn basic arithmetic.

Despite having a brain containing less than one million neurons, the honeybee has recently shown it can manage complex problems – like understanding the concept of zero.

Honeybees are a high value model for exploring questions about neuroscience. In our latest study we decided to test if they could learn to perform simple arithmetical operations such as addition and subtraction.




Read more:
Which square is bigger? Honeybees see visual illusions like humans do


Addition and subtraction operations

As children, we learn that a plus symbol (+) means we have to add two or more quantities, while a minus symbol (-) means we have to subtract quantities from each other.

To solve these problems, we need both long-term and short-term memory. We use working (short-term) memory to manage the numerical values while performing the operation, and we store the rules for adding or subtracting in long-term memory.

Although the ability to perform arithmetic like adding and subtracting is not simple, it is vital in human societies. The Egyptians and Babylonians show evidence of using arithmetic around 2000BCE, which would have been useful – for example – to count live stock and calculate new numbers when cattle were sold off.

This scene depicts a cattle count (copied by the Egyptologist Lepsius). In the middle register we see 835 horned cattle on the left, right behind them are some 220 animals and on the right 2,235 goats. In the bottom register we see 760 donkeys on the left and 974 goats on the right.
Wikimedia commons, CC BY

But does the development of arithmetical thinking require a large primate brain, or do other animals face similar problems that enable them to process arithmetic operations? We explored this using the honeybee.

How to train a bee

Honeybees are central place foragers – which means that a forager bee will return to a place if the location provides a good source of food.

We provide bees with a high concentration of sugar water during experiments, so individual bees (all female) continue to return to the experiment to collect nutrition for the hive.

In our setup, when a bee chooses a correct number (see below) she receives a reward of sugar water. If she makes an incorrect choice, she will receive a bitter tasting quinine solution.

We use this method to teach individual bees to learn the task of addition or subtraction over four to seven hours. Each time the bee became full she returned to the hive, then came back to the experiment to continue learning.




Read more:
Are they watching you? The tiny brains of bees and wasps can recognise faces


Addition and subtraction in bees

Honeybees were individually trained to visit a Y-maze shaped apparatus.

The bee would fly into the entrance of the Y-maze and view an array of elements consisting of between one to five shapes. The shapes (for example: square shapes, but many shape options were employed in actual experiments) would be one of two colours. Blue meant the bee had to perform an addition operation (+ 1). If the shapes were yellow, the bee would have to perform a subtraction operation (- 1).

For the task of either plus or minus one, one side would contain an incorrect answer and the other side would contain the correct answer. The side of stimuli was changed randomly throughout the experiment, so that the bee would not learn to only visit one side of the Y-maze.

After viewing the initial number, each bee would fly through a hole into a decision chamber where it could either choose to fly to the left or right side of the Y-maze depending on operation to which she had been trained for.

The Y-maze apparatus used for training honeybees.
Scarlett Howard

At the beginning of the experiment, bees made random choices until they could work out how to solve the problem. Eventually, over 100 learning trials, bees learnt that blue meant +1 while yellow meant -1. Bees could then apply the rules to new numbers.

During testing with a novel number, bees were correct in addition and subtraction of one element 64-72% of the time. The bee’s performance on tests was significantly different than what we would expect if bees were choosing randomly, called chance level performance (50% correct/incorrect)

Thus, our “bee school” within the Y-maze allowed the bees to learn how to use arithmetic operators to add or subtract.

Why is this a complex question for bees?

Numerical operations such as addition and subtraction are complex questions because they require two levels of processing. The first level requires a bee to comprehend the value of numerical attributes. The second level requires the bee to mentally manipulate numerical attributes in working memory.

In addition to these two processes, bees also had to perform the arithmetic operations in working memory – the number “one” to be added or subtracted was not visually present. Rather, the idea of plus one or minus “one” was an abstract concept which bees had to resolve over the course of the training.

Showing that a bee can combine simple arithmetic and symbolic learning has identified numerous areas of research to expand into, such as whether other animals can add and subtract.




Read more:
Bees get stressed at work too (and it might be causing colony collapse)


Implications for AI and neurobiology

There is a lot of interest in AI, and how well computers can enable self learning of novel problems.

Our new findings show that learning symbolic arithmetic operators to enable addition and subtraction is possible with a miniature brain. This suggests there may be new ways to incorporate interactions of both long-term rules and working memory into designs to improve rapid AI learning of new problems.

Also, our findings show that the understanding of maths symbols as a language with operators is something that many brains can probably achieve, and helps explain how many human cultures independently developed numeracy skills.


This article has been published simultaneously in Spanish on The Conversation Espana.The Conversation

Scarlett Howard, PhD candidate, RMIT University; Adrian Dyer, Associate Professor, RMIT University, and Jair Garcia, Research fellow, RMIT University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Our ‘bee-eye camera’ helps us support bees, grow food and protect the environment



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To help draw bees’ attention, flowers that are pollinated by bees have typically evolved to send very strong colour signals.
Shutterstock

Adrian Dyer, RMIT University and Tanya Latty, University of Sydney

Walking through our gardens in Australia, we may not realise that buzzing around us is one of our greatest natural resources. Bees are responsible for pollinating about a third of food for human consumption, and data on crop production suggests that bees contribute more than US$235 billion to the global economy each year.

By pollinating native and non-native plants, including many ornamental species, honeybees and Australian native bees also play an essential role in creating healthy communities – from urban parks to backyard gardens.

Despite their importance to human and environmental health, it is amazing how little we know how about our hard working insect friends actually see the world.

By learning how bees see and make decisions, it’s possible to improve our understanding of how best to work with bees to manage our essential resources.

Insects in the city: a honeybee forages in the heart of Sydney.
Adrian Dyer/RMIT University



Read more:
Bees get stressed at work too (and it might be causing colony collapse)


How bee vision differs from human vision

A new documentary on ABC TV, The Great Australian Bee Challenge, is teaching everyday Australians all about bees. In it, we conducted an experiment to demonstrate how bees use their amazing eyes to find complex shapes in flowers, or even human faces.

Humans use the lens in our eye to focus light onto our retina, resulting in a sharp image. By contrast, insects like bees use a compound eye that is made up of many light-guiding tubes called ommatidia.

The top of each ommatidia is called a facet. In each of a bees’ two compound eyes, there are about 5000 different ommatidia, each funnelling part of the scene towards specialised sensors to enable visual perception by the bee brain.

How we see fine detail with our eyes, and how a bee eye camera views the same information at a distance of about 15cm.
Sue Williams and Adrian Dyer/RMIT University

Since each ommatidia carries limited information about a scene due to the physics of light, the resulting composite image is relatively “grainy” compared to human vision. The problem of reduced visual sharpness poses a challenge for bees trying to find flowers at a distance.

To help draw bees’ attention, flowers that are pollinated by bees have typically evolved to send very strong colour signals. We may find them beautiful, but flowers haven’t evolved for our eyes. In fact, the strongest signals appeal to a bee’s ability to perceive mixtures of ultraviolet, blue and green light.

Yellow flower (Gelsemium sempervirens) as it appears to our eye, as taken through a UV sensitive camera, and how it likely appears to a bee.
Sue Williams and Adrian Dyer/RMIT University



Read more:
Bees can learn the difference between European and Australian Indigenous art styles in a single afternoon


Building a bee eye camera

Despite all of our research, it can still be hard to imagine how a bee sees.

So to help people (including ourselves) visualise what the world looks like to a bee, we built a special, bio-inspired “bee-eye” camera that mimics the optical principles of the bee compound eye by using about 5000 drinking straws. Each straw views just one part of a scene, but the array of straws allows all parts of the scene to be projected onto a piece of tracing paper.

How a bee eye camera works by only passing the constructive rays of light to form an image.
Sue Williams and Adrian Dyer/RMIT University

The resulting image can then be captured using a digital camera. This project can be constructed by school age children, and easily be assembled multiple times to enable insights into how bees see our world.

Because bees can be trained to learn visual targets, we know that our device does a good job of mimicking a bees visual acuity.

Student projects can explore the interesting nexus between science, photography and art to show how bees see different things, like carrots – which are an important part of our diet and which require bees for the efficient production of seeds.

Clip from “The Great Australian Bee Challenge, Episode 2.



Read more:
A bee economist explains honey bees’ vital role in growing tasty almonds


Understanding bee vision helps us protect bees

Bees need flowers to live, and we need bees to pollinate our crops. Understanding bee vision can help us better support our buzzy friends and the critical pollination services they provide.

In nature, it appears that flowers often bloom in communities, using combined cues like colour and scent to help important pollinators find the area with the best resources.

Having lots of flowers blooming together attracts pollinators in much the same way that boxing day sales attract consumers to a shopping centre. Shops are better together, even though they are in competition – the same may be true for flowers!

This suggests that there is unlikely to be one flower that is “best” for bees. The solution for better supporting bees is to incorporate as many flowers as possible – both native and non native – in the environment. Basically: if you plant it, they will come.

We are only starting to understand how bees see and perceive our shared world – including art styles – and the more we know, the better we can protect and encourage our essential insect partners.The Conversation

Looking at the fruits and vegetables of bee pollination; a bee camera eye view of carrots.
Sue Williams and Adrian Dyer/RMIT University

Adrian Dyer, Associate Professor, RMIT University and Tanya Latty, Senior Lecturer, School of Life and Environmental Sciences, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Honeybees hog the limelight, yet wild insects are the most important and vulnerable pollinators



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Szefei / http://www.shutterstock.com

Philip Donkersley, Lancaster University

Pollinating insects like bees, butterflies and flies have had a rough time of late. A broad library of evidence suggests there has been a widespread decline in their abundance and diversity since the 1950s. This matters because such insects are critical both for the reproduction of wild plants and for agricultural food production.

The decline of these pollinators is linked with destruction of natural habitats like forests and meadows, the spread of pests such as Varroa mite and diseases like foulbrood, and the increasing use of agrochemicals by farmers. Although there have been well documented declines in managed honeybees, non-Apis (non-honeybee) pollinators such as bumblebees and solitary bees have also become endangered.

There are more than 800 wild (non-honey) bee species in Europe alone. Seven are classified by the IUCN Redlist as critically endangered, 46 are endangered, 24 are vulnerable and 101 are near threatened. Collectively, losing such species would have a significant impact on global pollination.

Though much of the media focus is on honeybees, they are responsible for only a third of the crop pollination in Britain and a very small proportion of wild plant pollination. A range of other insects including butterflies, bumblebees and small flies make up for this pollination deficit.

Butterfly pollinating during monsoon season.
Hitesh Chhetri / http://www.shutterstock.com

Not all pollinators are created equal

Pollinators also vary in their effectiveness due to their behaviour around flowers and their capacity to hold pollen. Bigger and hairier insects can carry more pollen, while those that groom themselves less tend to be able to transfer pollen more effectively. Bumblebees, for example, make excellent pollinators (far superior to honeybees) as they are big, hairy and do not groom themselves as often.

Where they are in decline, honeybees suffer primarily from pests and diseases, a consequence of poor nutrition and artificially high population density. This differs from other pollinators, where the decline is mainly down to habitat destruction. It seems pesticides affect all pollinators.

An ashy mining-bee (Andrena cineraria) settles in for a snack.
Philip Donkersley, Author provided

Save (all) the bees

Curiously, the issues facing non-Apis pollinators may be exacerbated by commercial beekeeping, and attempts to help honeybees may even harm efforts to conserve wild pollinators.

The problem is that there are only so many flowers and places to nest. And once the numbers of honeybees have been artificially inflated (commercial-scale beekeeping wouldn’t exist without humans) the increased competition for these resources can push native non-Apis pollinators out of their natural habitats. Honeybees also spread exotic plants and transmit pathogens, both of which have been shown to harm other pollinators.

The European honey bee (Apis mellifera) is the most common species of honey bee.
Philip Donkersley, Author provided

Over the coming decades, farmers and those who regulate them are faced with a tough challenge. Agricultural output must be increased to feed a growing human population, but simultaneously the environmental impact must be reduced.

The agriculture sector has tried to address the need to feed a growing population through conventional farming practices such as mechanisation, larger fields or the use of pesticides and fertiliser. Yet these have contributed to widespread destruction of natural landscapes and loss of natural capital.

Limited resources and land use pressure require conservation strategies to become more efficient, producing greater outcomes from increasingly limited input.

A mosaic of different flowers: these sorts of landscapes are paradise for bees.
Philip Donkersley, Author provided

Cooperative conservation

So-called agri-environment schemes represent the best way to help insect pollinators. That means diversifying crops, avoiding an ecologically-fragile monoculture and ensuring that the insects can jump between different food sources. It also means protecting natural habitats and establishing ecological focus areas such as wildflower strips, while limiting the use of pesticides and fertilisers.

As pollinating insects need a surprisingly large area of land to forage, linking up restored habitats on a larger scale provides far more evident and immediate benefits. However, so far, connections between protected areas have not been a priority, leading to inefficient conservation.

The ConversationWe need a substantial shift in how we think about pollinators. Encouraging land managers to work cooperatively will help create bigger, more impactful areas to support pollinators. In future, conservation efforts will need to address declines in all pollinators by developing landscapes to support pollinator communities and not just honeybees.

Philip Donkersley, Senior Research Associate in Entomology, Lancaster University

This article was originally published on The Conversation. Read the original article.