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Bees and beyond

Because pollen sucks.

It does! But if you prefer the smart word: it’s hygroscopic. It attracts water.

And where is water, there is rot.
Which is a problem when you are an insect that relies on pollen to feed its brood and therefore needs to store pollen for weeks, if not months. You may be more or less okay when in a desert or at least able to avoid the rainy season – but in our friendly fertile temperate zones, you’re not.

Still, they are here. Plenty of them. Mason bees and leafcutter bees and carder bees and many more.

Photograph: Neil Bromhall

In their new paper, Christophe Praz and his colleagues suggest a scenario for just how this could have happened:

Before the bees began to feed pollen to their brood (i.e. before they actually became bees) they were something similar to today’s apoid wasps (Grabwespen). They were hunting other insects, paralysed their victims and dragged them into the broodnest where their prey would stay alive for several weeks before being consumed by the larvae.
You may find this disgusting or not, but keeping your food alive until consumption is definitely a good way to keep it fresh.
And there is nothing „primitive“ or old-fashioned about it. There are still plenty of wasps around who do exactly this. But this method does have its costs. Hunting takes time, it’s not without risks, chances to find prey are limited and so on. So when the flowering plants arrived and offered pollen as an alternative source of protein, the bees’ ancestors skipped their carnivorous habits and became all out vegetarians. Which – as we all know – turned out to be a smart move.

But before the flowers and the bees could become one of the biggest success stories on the planet, there was one more innovation needed.

From gene sequencing data and the analysis of diversification rates and biogeography, Praz and his colleagues conclude that for a long time bees had been restricted to arid evironments and that it was only after the „invention“ of traits to impregnate the broodchamber that they were able to achieve their impressive diversity (3900 species today) and worldwide expansion.

They also argue that nest-lining behaviour with foreign material was „invented“ only once within the megachilid bees, some 90 to 100 million years ago (as marked by the green star in the figure below).

[Click picture to enlarge]

So flowering plants and pollen were very important for bees to evolve. But if it hadn’t been for new behavioural traits that allowed to keep the pollen safe from spoilage through water and fungi, the megachilid bees would probably never have been able to leave the deserts.

The cell linings they produce can vary widely. Some bees use mud or chewed leaf paste, others coat the nest with cut out pieces of leaf, and some cement together little pieces of gravel. Whatever the material, all these linings seem to have water-repellent and anti-microbial properties.
There also are a few megachilid species that never got into cell-lining at all.
But they are still in the deserts.

 

Note: This is a slightly modified version of a post I have written in 2011. I decided to re-post it, because I am taking part in this years’ NESCent Blog Contest and I really like the bee-story. With bee populations struggling in so many places, I find it even more fascinating to see where they have come from, and how adaptive nature really is.

 

Litman JR, Danforth BN, Eardley CD, & Praz CJ (2011). Why do leafcutter bees cut leaves? New insights into the early evolution of bees. Proceedings. Biological sciences / The Royal Society PMID: 21490010

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A few weeks ago, the German weekly Die Zeit published my article about the entangled histories of bees, men and mites. It is now online and even received some comments!


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When researching for my article on Varroa for Die Zeit, I relied heavily on The World History of Beekeeping and Honey Hunting by Eva Crane, a nuclear physicist who turned beekeeper, bee researcher and founder of the International Bee Research Association (IBRA).

The book is a fascinating and almost inexhaustible resource, or, as Paul Theroux wrote in 2000:

… the classic that everyone interested in bees, beekeeping or honey in human history has been waiting for. There are many of us, and now we have our encyclopedic work. A whole library of slighter books exists on this and related subjects, but this is the masterwork – for its enormous scope and exhaustiveness, for being a treasure house of apiaristic facts as well as totally up-to-date.

Eva Crane herself was a fascinating person, too. After studying mathematics and quantum mechanics (then a groundbreaking field), she aquired a PhD in nuclear physics in 1937 and

although the concept of women having a career path may not have been recognised in the 1940s, […] Eva was certainly bound for academic heights when she took up lecturing posts in Hull and Sheffield Universities.
(Richard Jones in the Foreword to The World History… )

It was in 1942 when she aquired her first beehive (apparently as a wedding present), for purely practical reasons: to produce honey in a time of national sugar schortage. But these bees would change the rest of her life.
At the time (when there was no internet, barely a telephone in every household), Crane found it difficult to find information about research to help her improve the effectiveness of her beekeeping, and in the following years “the business of collecting, collating and disseminating information about bees and beekeeping became the dominant force in her life” (R.J.). In 1949 she founded the Bee Research Association, renamed International BRA (or IBRA) in 1976, where, among many other activities, she became the editor of Bee World and other publications. She also was a traveler:

For more than a half-century Dr. Crane worked in more than 60 countries to learn more and more about honeybees, sometimes traveling by dugout canoe or dog sled to document the human use of bees from prehistoric times to the present. She found that ancient Babylonians used honey to preserve corpses, that bees were effectively used as military weapons by the Viet Cong, and that beekeepers in a remote corner of Pakistan use the same kind of hives found in excavations of ancient Greece. (Douglas Martin, New York Times)

 

 

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Image: IBRA

The Varroa mite is widely recognized as today’s most serious pest of the Western Honeybee (Apis mellifera), so its rather menacing scientific name of Varroa destructor seems only natural and fitting.
However, when the mite was first discovered in Java in 1904, it had never even met a Western Honeybee, let alone damaged one, but was an altogether inconspicuous species living in a well-balanced relationship with the Eastern Honeybee (A. cerana). And A.C. Oudemans, who first described it as a species, may have been a remarkable man, but he was in no way prescient concerning the enormous threat the mite would become some hundred years later. He therefore named it, quite conventionally, Varroa jacobsoni after its collector.

For a long time, this was of little interest to anybody.

During this time, all Varroa mites were thought to belong to one of three species: V. jacobsoni, V. underwoodi, V. rindereri, with V. jacobsoni having the widest distribution on A. cerana and being the only species to parasitise A. mellifera. Which, of course, eventually, brought it to the attention of the bee researchers. Varroa jacobsoni soon became one of the closest studied mite species in the world.

Despite all this attention, there was very little morphological variation to be found within V. jacobsoni. From the outside, all mites looked the same. But there was a marked difference in their virulence toward A. mellifera. V. jacobsoni of Javanese origin, for example, were completely unable to reproduce on A. mellifera (and therefore much less damaging for the bees), whereas mites from other locations thrived on the western bees and caused great losses in managed and feral hives.

So the question was: What is different between the „harmless“ mites from Java and the virulent types from other places?

Dr. Denis Anderson

All through the 1990s, the Australian entomologist Denis Anderson and his colleagues had been collecting and comparing specimens of V. jacobsoni from all over the world. They found, that despite their uniform appearance, jacobsoni-mites were genetically quite diverse, and identified 18 haplotypes (mites with distinct sequences in their mitochondrial DNA) on A. cerana in Asia (the original host). Of these 18 haplotypes, only two had become pests of A. mellifera. The team also showed, that mites living on A. mellifera do not mix with mites living on A. cerana. They are reproductively isolated.

In the their publication in the year 2000, they concluded that

…the between-clade differences are sufficiently large to represent differences between species.

Meaning: They had discovered Varroa destructor.

For an insight into the reception of this discovery, I strongly recommend the guest editorial in Bee World from 2001 by Keith S. Delaplane, an entomologist at University of Georgia:

During the 1990s many workers contributed to the “revolution” that was heating up, but it was Anderson and Trueman who dealt the old paradigm its death blow. The mite we were all dealing with, we learned, was not Varroa jacobsoni at all. This much-maligned species turns out to be a benign homebody, still restricted essentially to its original host A. cerana in Indonesia as Jacobson found it, and not the culprit to worldwide calamity we had thought. For this we needed a new culprit, and Anderson and Trueman found it. They not only found it and named it, they named it in a glorious flourish of melodrama, appropriate in this case and all too rare in the stuffy halls of academe – Varroa destructor. Let your tongue roll on that one. Here’s a Linnaean name anyone can appreciate.

At the time, despite the “glorious flourish of melodrama”, there was hope that Varroa might be defeated through making use of the new genetic information. But so far, V. destructor is still thriving.

ResearchBlogging.org

Anderson DL, & Trueman JW (2000). Varroa jacobsoni (Acari: Varroidae) is more than one species. Experimental & applied acarology, 24 (3), 165-89 PMID: 11108385

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Before Varroa destructor got this rather menacing name, it was called Varroa jacobsoni after its collector by the Dutch zoologist Anthonie Cornelis Oudemans.

 

This is the wall of Oudemans Crater on Mars. Named after Oudemans (the astronomer) and located right here. (Image: NASA)

Oudemans was the son of the noted astronomer Jean Abraham Chr̩tien Oudemans, who had spent the years between 1857-1875 in the Dutch East Indies (now Indonesia, more or less), where he Рamong many other things Рpublished six volumes on the triangulation of Java.

Oudemans (the astronomer) on his trip to Réunion in 1874 to observe the Transit of Venus

 

Java in turn happens to be the place where Varroa jacobsoni was first found by the collector E. Jacobson, who sent it to Oudemans’ son in the Netherlands, who in turn published its taxonomic description in 1904. Anthonie Oudemans, the son, later donated his collection of 1316 mite species to the Rijksmuseum. His original catalogue can be found here, with Varroa jacobsoni duly mentioned on page 300:

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Aside from mites, Oudemans was also interested in larger animals. In 1892, he published The Great Sea Serpent, a study of the many sea serpent reports from around the world. Oudemans concluded that the sightings might refer to a previously unknown large seal, which he dubbed Megophias megophias. His work was later considered to be one of the first in cryptozoology.

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As I wrote before, we are trying to get our heads around a few things related to bees and social insects in general. One of them is the concept of the Superorganism (which somehow seems to be much more readily embraced in popular culture than among biologists).

Two prominent proponents of the superorganism-concept are Bert Hölldobler and E.O. Wilson and their book “The Superorganism” is a phantastic source of examples from the natural history of social insects. Although “ant-people” by profession and inclination, they have plenty of stories to tell for “bee-pople” as well.

„[O]ur intention here is to present the rich and diverse natural history facts that illustrate superorganismic traits in insect societies and to trace the evolutionary pathways to the most advanced stages of eusociality.

Our intent in doing so is to revive the superorganism concept, with emphasis on colony-level adaptive traits, such as division of labor and communication. Finally, in presenting the subject this way, we visualize the colony as a self-organized entity and a target of natural selection.

In this book, we view the insect colony as the equivalent of an organism, the unit that must be examined in order to understand the biology of colonial species.“

Hölldobler and Wilson strongly argue that natural selection works on several levels, not just on individuals and their genes, but on groups as well.

„Life is a self-replicating hierarchy of levels. Biology is the study of the levels that compose the hierarchy. No phenomenom at any level can be wholly characterized without incorporating other phenomena that arise at all levels. (…) Natural selection that targets a trait at any of these levels ripples in effect across all the others.“ (pp 7f)

So, while the “selfish gene” does play an important role, they see other mechanims at work as well.
More on the history of the different evolutionary concepts you can find in this interview with Bert Hölldobler on Wired.

Aside from the debate about underlying evolutionary principles, I do like the focus of the superorganism concept on self-organization and decentralized, bottom-up processes. There is no “brain-caste” in insect societies. “Order” and “intelligence” are achieved by cooperation alone. Cooperation according to some very strict and unrelenting rules, though (or behavioral patterns, if that’s a better term).

Also, by the way, Ed Yong reports some compelling Mathematical Support for Insect Colonies as Superorganisms.

Und: “Der Superorganismus” ist inzwischen auch in deutscher Ãœbersetzung verfügbar.

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While the bees have done the smart thing and huddled up for winter, we are wide awake and using the snowy days for catching up on reading and working on the “wider picture”.

There is a lot about bees that is interesting, and the more we study them, the more we keep encountering new and strange and unexpected connections that reach way beyond bees and biology.

Take the superorganism.

Now I know what you are thinking (or what you would be thinking if you were anything like me):

The Borg-Cube

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