Research haikus

Last month, the Zoology Department’s Dr. David Kelly launched his first book of Japanese short form poetry, Hammerscale from the Thrush’s Anvil. At the launch of the book, David invited us in the audience to try our hand at writing our own haikus.

Taking him up on his challenge, and taking inspiration from his book, a few of us in the School of Natural Sciences have penned our own poems based on our areas of study. We even have a contribution from David Kelly himself!

Trying not to sacrifice coherency at the alter of syllable number was a rather new struggle for most of us, but we managed and, I’d like to think, emerged with a greater appreciation for the poets in our midst. Read on for our science-y foray into the arts!

(Paula Tierney @_ptierney)

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Yellow red fish eyes

Maybe that’s a nematode?

No, it is more fish

Paula Tierney

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Carbon fixed by plants

Then sequestered in the soil

Helps to keep Earth cool

Matt Saunders

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Hoverflies hover

Syrphidae flying over

Gardens of flowers

Sarah Gabel

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Monochrome poets

Curved claws etching musky spoors

Into the cold night

Aoibheann Gaughran Continue reading “Research haikus”

Ecology & Science in Ireland: the inaugural meeting of the Irish Ecological Association

 

In the years to come, 140 ecologists working in Ireland will look back with fond memories of being part of the inaugural meeting of the Irish Ecological Association (24th-26th November). We will remember hard-hitting plenaries, compelling oral presentations, data-rich posters, influential workshops and the formation of the IEA’s first committee. The lively social events might be harder for some of us to remember…

There could not have been a more fitting way to open the conference than the plenary seminar from Professor Ian Montgomery (QUB) on Thursday night. Within the hour, he managed to given an incredibly detailed summary of the natural history of Ireland, showing how Ireland had been an island for 16,000 years and presenting evidence that human occupation dated back 13,000 years. Ian stepped us through successive mammal invasions, classifying them as true ‘natives’ and more recent ‘invasives’. His seminar was open to the public and the audience included local farmers with strong concerns about the impacts of invasive mammals on their stock.

We were welcomed the following morning with an energetic plenary from Professor Jane Memmott (U Bristol), covering her strikingly diverse career. She took us on a journey from life as a medical entomologist, to tropical ecologist living in a Costa Rican jungle tent, to invasion biologist in the land of invasives – New Zealand, to her more recent work on biodiversity in urban and farmland systems. Quantitative food webs were the central theme. Using both simple and complex food webs, based on enormous data sets, Jane clearly showed that we only see the full story about ecosystem dynamics by examining links between trophic levels. Continue reading “Ecology & Science in Ireland: the inaugural meeting of the Irish Ecological Association”

Shall we kill all our bees?

1024px-Bee_covered_in_pollenKill all the bees!!”, the modest proposal of Prof. Paul Sutton from University of South Australia is a provocative attempt to convince economic rationalists to finally start counting what really counts.

If all the bees were to go extinct we will have to replace them by, for example, hand-pollinating our crops. That means employment, economic growth in terms of GDP and tax revenues: very good for the Economy.

Now, the fact that not many economists will actually support this policy does not change the fact that if all the bees are going to be gone then GDP would actually rise, jobs would actually be created as well as tax revenues.

This is a market failure too big to be ignored! We need to “abandon magical thinking about free markets and invisible hands … and develop appropriate worldviews that are broader than the narrow economic worldview we are currently trapped in”. The services provided by healthy ecosystems should be considered too big to fail, just like the big banks.

Environmental scientists have lost an argument with economic rationalists. The evaluation of ecosystem services strives to use a common language between environmental sciences and economics.

Economists are the primary advisors of governments. We need environmental scientists with the same decisional power to face future challenges deriving from our current model of infinite growth on a finite planet.

Author

Luca Coscieme, coscieml[at]tcd.ie

Photo credit

Wikimedia commons

Mixed Messages, Pesticide Pestilence and Pollinator Populations

Honey_bee_on_flower_with_pollen_collected_on_rear_leg

“We’re getting mixed messages from scientists about the effects of neonicotinoids on bees” – I have heard this from several sources, including a very senior civil servant in the UK and from an intensive tillage farmer in Ireland. A recent article in the US media says pretty much the same thing. An article in the Guardian last week entitled “UK drew wrong conclusion from its neonicotinoids study, scientist says”, reports on Dave Goulson’s reanalysis of the Food & Environment Research Agency (FERA)’s own data, but draws the opposite conclusion.

So why is there confusion on bee decline and the role of neonicotinoids? I believe it’s down to several factors:

1. “Bees” are a diverse taxonomic group of insects, including the well-known eusocial honeybee Apis mellifera, the familiar bumblebees in the genus Bombus, plus hundreds of other species of bee, which have quite different life histories and ecologies, most of which do not form social colonies. When talking about bees, we need to be clear about which ones we are discussing. If everyone is clear about which taxonomic group they are talking about, this could cut down considerably on the confusion. (By the way, the Guardian used a picture of honeybees as the image accompanying their article on bumblebees).

2. Honeybees are managed by beekeepers. If a colony dies out (especially over winter in temperate countries), it is replaced by splitting a strong colony in spring. If the colony is sick, it is treated. When we talk about honeybee decline, we are either referring to colony losses (i.e. colonies dying out, which can be caused by a range of factors, especially parasites and diseases, and is highly spatio-temporally variable); OR we are referring to the fact that there are fewer beekeepers out there, or that each one is keeping fewer colonies. The point is, when colonies die out, beekeepers can restock and the total number of honeybee colonies depends on the activity of beekeepers. This is why there appears to be no decline in honeybees in the US. This is not the case for wild bees.

3. Eusocial bees, by the very nature of their colonial societies, are to some extent buffered against environmental stochasticity and pressures. If a few hundred honeybees are killed whilst out of the hive foraging during the summer, it may have little impact on the colony, because there are 50,000 or more honeybees left in the hive. This may be a reason why lab-based findings cannot always be scaled up when replicated at field level. Measuring effects at the colony-level is also another problem. A range of different experimental approaches has led to mixed conclusions on the effects of neonicotinoids on honeybees.

4. A huge number of independent peer-reviewed studies have shown negative lethal and sub-lethal effects of neonicotinoids on wild bees and other non-target organisms (e.g. see review by Pisa et al. 2015), in laboratory, and semi-field studies. Realistic field-level studies on the other hand are challenging methodologically: some bees have large foraging ranges and so studies must be conducted over large areas; pesticide free “control” sites are very hard to find; and wild bees are subject to a range of interacting pressures (loss of forage resources, parasites and disease, cocktails of pesticides, use of managed bees for pollination purposes, climate change…), and disentangling the effects of these pressures in a field experiment is hard. However, those few studies that have been conducted properly appear to support the lab and semi-field findings.

5. The media band-wagon… When the media polarise environmental issues, it’s very hard for people to make an informed decision – instead of crediting the general public with the intelligence to understand that the environment is highly variable in both space and time, and that ecological systems and interactions within them are highly complex, issues are presented as cut-and-dried in one direction or another. Thus the confusion is maintained, so that the next big news story, that contradicts the previous one, can have a bigger impact.

There shouldn’t be any confusion – neonicotinoids have sufficient negative impacts on non-target organisms for us to be concerned about their widespread and often prophylactic use (e.g. as seed dressings). We should also worry about the wider environmental impacts of pesticides like neonicotinoids – how persistent they are, how they get into the soil and water-courses and affect other organisms that provide essential ecosystem services. And we shouldn’t just be concerned about neonicotinoids – the massive cocktail of chemicals we intentionally and accidentally unleash on the natural environment could have long-term and very damaging effects to our natural capital. Including bees.

Author: Jane Stout, stoutj[at]tcd.ie

Photo credit: wikimedia commons

Seminar series highlights: Phil Stevenson

hoenybee

As mentioned previously on the blog, Andrew Jackson and I started a new module this year called “Research Comprehension”. The module revolves around our Evolutionary Biology and Ecology seminar series and the continuous assessment for the module is in the form of blog posts discussing these seminars. We posted a selection of these earlier in the term, but now that the students have had their final degree marks we wanted to post the blogs with the best marks. This means there are more blog posts for some seminars than for others, though we’ve avoided reposting anything we’ve posted previously. We hope you enjoy reading them, and of course congratulations to all the students of the class of 2014! – Natalie

Here’s articles from Maura Judge and Chris Parsisson inspired by Professor Phil Stevenson‘s seminar, “Pollinator fidelity in coffee and citrus: is it all just sex and drugs?”

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An unlikely love story

Maura Judge

This is the story of a certain love affair, commonly known as floral constancy. The story involves pollinators and flowers. Floral constancy is the tendency of a pollinator to remain faithful to and exclusively visit a certain flower species or morphospecies. Whilst remaining faithful, the pollinator bypasses other available flower species that could potentially be more rewarding.

So what are the drivers of this phenomenon? For the plant species, the benefits are more obvious as pollinators that are flower faithful are more likely to transfer pollen to other flowers of the same species and hence, flower constancy favors flower pollination. Furthermore, flower constancy prevents the loss of pollen during interspecific flights and prevents pollinators from clogging stigmas with the pollen of other flower species. Hence, the reasons for the evolution of floral constancy in plants are obvious.

However, what could be the benefits for a pollinator? To ignore other flowers that could potentially provide more nectar than their preferred type contradicts the optimal foraging theory. Nonetheless, floral constancy has been observed in honeybees (Apis mellifera), bumblebees (Bombus terrestris) and butterflies (Thymelicus flavus). Drivers of floral constancy are rewards associated with cues such as flower shape, colour or scent. For example, honeybees have been found not to attempt to feed on other available flowers that exhibit an alternative colour to their preferred flower type. One hypothesis for the evolution of floral constancy in pollinators is that insects can only identify and handle one flower type or species at a time due to their limited memory capacity.

There are three other hypotheses for the evolution of floral constancy in pollinators. The first is the learning investment hypothesis which refers to the ability of a pollinator to learn a motor skill to obtain nectar from a certain species of flower. Learning these motor skills requires a substantial investment of energy and switching to other flower species could be energetically costly and hence, inefficient and non-adaptive. Furthermore, feeding from one particular plant species increases the insect’s efficiency to obtain nectar from it. The second hypothesis is the costly information hypothesis which states that pollinators stay faithful to one plant species because they know that they obtain a reliable reward from it, i.e. nectar. Hence, the pollinator does attempt to feed on other plant species because it cannot predict the amount of nectar in other flowers and could essentially waste foraging time and energy on flowers that contain possibly less or even no nectar. The third alternate hypothesis is the resource partitioning hypothesis. It states that, in social foragers, flower constancy could benefit the entire colony as if individual foragers specialize on specific flower species, foragers avoid competing with one another. Thus floral constancy would increase foraging efficiency.

In addition, Prof. Stevenson and his colleagues have found evidence for another hypothesis in which toxins such as caffeine are the drivers of floral constancy in pollinators. Evidence for this came from bees being found to be more likely to forage on the same plant species if it contained caffeine and less likely to confuse it with similar signals from other plant species. They have found evidence of plant defence compounds enhancing the memory of reward in pollinators. Honeybees rewarded with caffeine, which occurs naturally in coffee and citrus plant species, were three times as likely to remember a learned floral scent as honeybees rewarded with sucrose alone. Thus, this proposed hypothesis ties the little understood phenomenon of floral constancy in with the little understood ecological role of plant defence compounds occurring in floral nectar.

Admittedly, this love affair is not as rosemantic (pun intended) as Romeo and Juliet’s. However, it is very intriguing nonetheless and the mechanisms behind it are still very uncertain. Exciting new evidence underlying the mechanisms involved is being found by Stevenson and his collaborators and it seems likely that it is not solely Britney Spears who finds toxicity attractive.

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The deviousness of flowers

Chris Parsisson

It should have come as no surprise to us that flowers act as drug pushers to get their evil way. Phil Stevenson of The University of Greenwich and Kew gave a short talk about the loyalty of pollinators to nectar producers.

Flowers have many devious tricks and will stop at nothing to reach their ultimate reproductive goals.  A world before flowers must have been a drab place with wind pollination being the order of the day and clouds of pollen wafting across the countryside in a desperate bid to land on a female plant part and perpetuate the gene line of the parent. No colourful flowers, no enticing perfume, no sweet honey. Just a hay fever sufferer’s nightmare. No wonder some plants formed a partnership with pollinators to streamline the operation.

And what a partnership it was! Insects often took on the role of pollinators and tied their fortunes to the plants’ success as plants tied themselves to the pollinators. Flowers evolved colours and scents to attract insects then often refined their flowers for special partners. Bees and wasps became preeminent in pollination and became dependent on supplies of nectar and pollen for their living. Always lured in by the flowers their co-evolution made both mutually dependent. The beauty of flowers and scents led to human intervention and flowers were developed with multiple petals and constant flowering periods but these developments often led to sterile flowers or loss of scents the need for human pollination. Isn’t it always the way? But who is keeping score? The millions of cultivated roses grown around the world must outnumber the wild roses in hedgerows so again the inclusive fitness of the roses, originally chosen for a brighter or extra petal, was assured. We too were seduced by the flowers into serving their nefarious schemes.

We discovered in recent decades that the colour we see on a flower is not the same as that seen by many pollinators. Bees see more in the ultra violet range and the patterns they perceive on many flowers lead directly to nectaries or to the stamens for a dusting of pollen or to shed some onto the stigma in this joint effort. No wonder many cultivated flowers with their multiple petals, lack of scent and vibrant colours are inaccessible to many bees, the landing instructions are lost and the nectaries have often been sacrificed for more petals. Best leave the cultivated flowers for the humans, enthralled by the flowers’ guile.

We know that some orchids lure male bees in with the promise of quick uncomplicated sex. Like a seaport pimp enticing a sailor down an alley with promises of beautiful girls nearby, the orchid entices him in and delivers nothing. The female bee is really another co-evolved flower and the male gets nothing for his trouble. The orchid delivers its pollen onto the bee’s back and off he goes looking for another flower. The floral equivalent of robbing the sailor and sending him staggering off into the night.

Now, it seems, we find that flowers are demanding loyalty of bees by slipping them drugs without their knowledge. Small amounts of caffeine are included with the nectar at a level thought to be below the taste consciousness of the bee but enough to make it remember the hit it got and return for more. This occurs in many coffee species and also in citrus species. It makes evolutionary sense. All flowering plants are competing with every neighbouring flower. If they weren’t and there were enough pollinators to go around all flowers would be simple in form and give out a minimum amount of nectar. That’s why flower form evolved so dramatically. The cunning flowers need an extra edge to ensure that bees come back to them as long as their flower lasts. Many flowers need a pollinator to visit more than once: to take away pollen to another flower and to bring in pollen. Often the female stigma ripens at a different time to the male anthers to prevent self-fertilisation so multiple visits may be ensured by making a bee remember the little lift it got at a particular plant.

Pollination is a serious business as 65% of crops are insect pollinated. Concerns about sudden hive collapse of honey bees and losses of pollinators are real. Even the managed bees are not enough for all pollination needs so wild pollinators must be carefully watched. Large monocultures may be detrimental to bees as tests have shown that levels of amino acids in some nectar may be harmful if eaten in excess.

Many leads could follow this research as a way to best serve the pollinators but, rest assured, those devious flowers will be still full of tricks.

Image: Wikicommons

Big is better!

INTECOLlogo

Reflections on geeking it up at Intecol 2013 by Jane Stout

Having not been to a 2000+ delegate, multi-session, international conference for several years, I was a bit nervous in the run up to INTECOL2013 “Into the next 100 years: advancing ecology and making it count” – would it be possible to see all the talks, read all the posters and meet all the people I planned to? (Answer: no). Would I remember everyone and would anyone remember me from past meetings? (Answer: some yes, some no – thank goodness for name tags). Could I follow in the footsteps of Katie Taylor, the last girl from Bray to take the stage at the London ExCeL Arena, and take the Olympic gold? (Answer: no; note to self: must try harder). But I needn’t have worried – INTECOL 2013 was excellent: it was well organised, the quality of the science was top-notch, the sun shone, and the whole thing was very inspiring and humbling.

First off, there were some excellent plenaries. Georgina Mace’s talk on “Looking forwards not backwards: Biodiversity conservation in the 21st century” was particularly lucid and inspiring, even though one of the things that I remember best was when she did look backwards, at what she termed the four “ages of conservation”: 1. Nature for itself (all about protected areas, species, populations), 2. Nature despite people (all about the terrible things humans have done to nature – threats and drivers – I think this was more or less when I started my BSc), 3. Nature for people (ecosystem function, ecosystem services) and 4. People and nature (about changes and dynamics, involving more socioeconomics etc.). She highlighted that conservation focus has moved fast but the science has not necessarily kept up. And that extremes not averages may matter more in the future.

Bill Sutherland’s plenary on “How do we improve decision making?” was also really good – he talked about how (not) to make decisions and stressed that good scientific evidence was not only fundamental, but needed to be effectively communicated in order to be taken into account.  He also highlighted some research into so-called “experts” which was fascinating (see Bergman et al. 2011). The panel discussion following Bill’s talk was really good, especially as it was effectively and humorously chaired by Professor Sue Hartley (Director – York Environmental Sustainability Institute). Having Bob May describe his position as the first Chief Scientist to the UK government was really interesting – and made me realise how great it would be if we had a similar position here in Ireland.

David Tilman managed to pull a plenary talk out of the bag at <48hrs notice, which was not only impressive in itself, but also an excellent talk. He described some of the findings from the Cedar Creek biodiversity plots which show the importance of biodiversity (“I knew biodiversity was going to be important, what I hadn’t realised was just how important”) and talked about how it wasn’t necessary to trade biodiversity off against food production – we just all need to eat less meat. He suggested that we all to invite friends round and cook vegetarian food (try this veg curry!).

Aside from the plenaries, there were heaps of really interesting talks. There were so many good titles that there wasn’t a hope of seeing everything that I wanted to. The thing that amazed me was how many pollination related talks there were. The last time I went to a conference like this there was maybe half a dozen pollinator talks. At this meeting there were at least 44 oral presentations with something to do with pollination or bees in the title. Hardly surprising given all the media hype associated with bee decline, but great to see how this field has grown in the past 10 years.

I was fortunate enough to speak in the symposium “Threats to an ecosystem service: evaluating multifactorial pressures on insect pollinators”, which included a really excellent introduction by Claire Kremen, who described, among other things, almond pollination in the US – millions of honeybee colonies are shipped into California from all over the country to pollinate almonds because there are no wild bees left in the orchards. One of the things she’s working on is introducing native wild plants in hedgerows into the landscape – made me realise how lucky we are here in Ireland with our complex landscapes full of hedgerows. Many of the other speakers in this session were talking about work they have done as a result of the Pollinator Initiative funding in the UK. There’s some excellent work going on there. The symposium was followed by a social event which apparently was sort of like speed dating but with “experts” moving around the room speaking to different people (who were mostly equally, if not more, expert themselves). Not sure whether it really worked, but there was a glass of wine in it for everyone (and no dating involved thankfully).

I saw some really nice presentations by current PhD students – some of my favourites were Alistair Campbell from Lancaster talking about enhancing beneficial insect communities and their services in cider apple orchards by planting flower strips; Gita Benadi from Wurzburg talking about her work on phenological synchrony between plants and pollinators and implications of shifts in either taxa with climate change; and Katherine Orford from Bristol talking about her work on how grassland management affects pollinator community diversity, function and biomass. Keep an eye out for their papers…

I didn’t manage to get to the BES birthday party, which was apparently great fun, but there were some great social interactions (shame about the beer – this part of London is so new there aren’t any decent pubs). We did take the cable car from the Excel Arena to the O2 Arena aka Millennium Dome and then a boat up the River Thames which was cool. And the sun shone! Happy geeky nerdy sunny ecology days…


Author:

Jane Stout: stoutj[at]tcd.ie

@JaneCStout

Image source:

intecol2013.org 

What I did this summer: Tortured some bees

Bumble-bee_on_Rhododendron

Among the multiple pressures currently driving decline in bee populations, little attention has been given to naturally occurring toxins in plant nectar.  We carried out research this summer on invasive Rhododendron ponticum, a plant that contains neurotoxins in its floral nectar.  We found this toxin to be lethal to honeybees, but apparently benign to the plant’s main pollinators, bumblebees.  Differential responses by bee species to toxins and other pressures means we need to consider bee decline on a species by species basis.

It is well documented that bee populations worldwide are in trouble, and we’ve written about this on the blog before.  From peer reviewed scientific literature to the August 2013 issue of Time magazine, everyone is talking about declines in bee populations.  Bees are important pollinators and contribute to the pollination of 75% of our crop species, which translates to 35% overall global crop production.  The downfall of wild and domestic pollinators could pose serious risks for food security and ecosystem function.

Most people agree that the decline of bees can’t be attributed to one specific cause.  Instead, multiple pressures such as habitat loss (including loss of forage plants, as well as nesting, mating and overwintering sites for wild bees), and exposure to new diseases and parasites are probably all contributing.  One of the suspected drivers of bee decline that has received a lot of media coverage lately is exposure to synthetic pesticides, especially neonicotinoids, which end up contaminating the nectar and pollen of bee-pollinated crops.  Surprisingly though, pesticides aren’t the only potentially harmful chemicals bees are exposed to in their food.  They also have to cope with natural plant toxins in nectar and pollen.  Plants often produce toxic secondary compounds, such as alkaloids, terpenes, and phenolics, to defend against herbivorous insects, like aphids and caterpillars.  We humans tend to use many of these chemicals for our own purposes- for example, nicotine (found in nicotiana plants) and caffeine (in citrus and coffee plants).  But plant nectar is generally thought to function as a reward for pollinating insects like honeybees.  Why then do we find these deterrent chemicals in floral nectar?  And how are they impacting honeybees and wild bees?  This is a large part of my PhD project, see this old blog post for more detail.

Researchers in the lab of Dr. Jane Stout at Trinity College Dublin are studying drivers of bee decline, and a current project focusses on a plant that contains toxins in its nectar, Rhododendron ponticumRhododendron is an ecologically damaging invasive plant in Ireland and Great Britain, famous for the problems it has caused in forest ecosystems in places such as Killarney National Park.  This plant grows in moist, acidic soil, and often takes over the understory and edges of forests, shading out other floral resources.  The work done at Trinity (in collaboration with Dr. Phil Stevenson at Greenwich University and Dr. Geraldine Wright at Newcastle University) has found that Rhododendron contains a class of toxic chemicals known as grayanotoxins (GTX) in its nectar and pollen.  These chemicals are neurotoxins, which block the sodium channels of insects and cause neurological symptoms, like paralysis.  To certain insects, this toxin can be lethal.

I am doing a PhD with Dr. Stout and one of my studies is investigating how GTX from Rhododendron nectar affects Irish bees.  Together with undergraduate Zoology students Tara English and Sharon Matthews, I’ve performed assays using honeybees, bumblebees, and solitary bees.  We fed the bees sugar solutions that are designed to mimic floral nectar, but bees in one treatment are fed solutions containing the toxin and their survival and behavior is compared to control groups, fed solutions containing no chemicals.  Surprisingly, the consequences of ingesting GTX from Rhododendron were very different depending on which species of bee was being tested.

Bumblebees can be seen feeding on Rhododendron every May and June in Ireland, and so, as you would expect, they have no apparent negative reaction to consumption of GTX: there was no impact on survival or behavior.  Solitary bees are more rarely found feeding on Rhododendron.  In the lab, no differences in survival were detected in one species of Andrena, but these bees showed behavioral changes.  Bees flipped on their backs and twitched for hours after eating solutions containing GTX.  They eventually recovered, but one can imagine that this behavioral response could make them easy targets for predators like birds, and prevent them from foraging and provisioning their nests in their usual way.

Lastly, and most dramatically, were the effects on honeybees.  Honeybees showed an almost immediate neurological response to consuming solutions containing nectar-relevant concentrations of GTX: within fifteen to twenty minutes, the bees began twitching and lost antennal function.  Some unrolled their proboscis and couldn’t role the tongue-like structure back in, while others regurgitated the liquid as soon as possible.  Regardless of their symptoms, within three to six hours, bees fed the GTX solution were dead.

Even though the effect of GTX on honeybee survival is dramatic, compared to the other pressures on the industry, Rhododendron is probably not a huge problem for honeybees.  Field surveys by the TCD researchers show that honeybees are not found foraging on Rhododendron in Ireland, even when hives are kept in the middle of a forest invaded by the plant.  Honeybees have a remarkable ability to communicate which are the best plants to collect nectar and pollen from, and it’s likely that they quickly learn to avoid this toxic plant.  Still, Rhododendron is likely preventing the growth of other plants that might provide forage resources for honeybees, to some extent changing the landscape in an unfavorable way for this species.  But our work, in combination with previous work from the Stout laboratory, shows honeybees do not represent the entire ecological story.  A study carried out in 2006 and 2007 by Anke Dietzsch showed that the number of bumblebee colonies of two species was higher in areas invaded by Rhododendron when compared to uninvaded control sites in both years.  Rhododendron provides a huge amount of nectar and pollen early in spring that this group of bees can take full advantage of.  So is Rhododendron good for bees or bad for bees?  Turns out it depends what bee species you’re talking about.

The species-specific response to the toxin in Rhododendron nectar is surprising, and emphasizes that not all bees are the same.  It’s easy to group these insects into one category, but the impacts of chemicals and other pressures could be very different for each species.  It also emphasizes that honeybees are facing many challenges in our changing landscape.  Some of these challenges, like habitat change from invasive species and exposure to chemicals, can interact to make the picture even more complicated.  Pollinators, including honeybees, need all the help we can provide.

Work on the toxic nectar of Rhododendron ponticum is funded by Science Foundation Ireland, with additional support from the U.S. National Science Foundation, Irish Research Council’s EMBARK Postgraduate Scholarship Scheme, and the Wellcome Trust.


 Author:

Erin Jo Tiedeken: tiedekee[at]tcd.ie

@EJTiedeken

Photo source:

Wikicommons

 

The popularity of bees

714px-Honey_Bee_takes_Nectar

Because my research often uses bees as the study subject, friends and family are always forwarding links to news and culture that concerns these fascinating creatures.  Let me list for you some of my favourites: I found this article about the debate surrounding the ban on neonicotinoids within the EU on twitter.  On a lighter note, a performance group teamed up with a group of monks at Glenstal Abbey to compose a “Song of the bees” based on scientific recordings and data from honeybees.  A friend on facebook sent me this comic, which describes the seeming absurdity of honeybee workers sacrificing themselves for their hives.  Another facebook find was this spoof article which points out that we could probably solve the problem of bee decline if bees privatised.  Finally, friends and family in Philadelphia informed me that Drexel University recently named its new department the BEES department!  That last one is a little deceiving because BEES stands for Department of Biodiversity, Earth and Environmental Science, so they don’t actually focus on the study of bees.  I think it’s still significant that the department’s acronym features our little buzzing friends though.  In addition to these references, the birthday and Christmas gifts I’ve received over the past three years include bee embroidered hand towels, wine glasses with bees painted on them, a bracelet with a bee charm, and a stuffed bee .

What is apparent from all of these links and articles (and the availability of the plethora of bee paraphernalia my lovely friends and family continue to buy for me), is that bees are incredibly popular right now.  And I can’t help but ask myself, what is the attraction?

My first question was am I just noticing these references more because I started studying bees in the last few years?  Honestly if you asked me to point out the difference between a honeybee and a bumblebee before I went to college, I’m sure I wouldn’t have been able to do it. But it turns out it’s not personal bias, not according to the scientific literature anyway.  The graph below is the result of a search in Web of Science for papers that contain the word “bee” or “bees” in the topic.  Clearly there has been increased interest in bees since the 1940’s.  In the last few years the publications on bees have been especially numerous, for example there were 1796 records in 2012.

graph

Okay, so bees are being studied more.  But why does the public seem to be so intrigued by these organisms? Why do people love bees?

I have a few thoughts- I’ll start with the obvious:

1.) Bees make honey.

Or so many think.  In reality, not all bees make honey.  The honey-like substance that bumblebees produce would not be fit for consumption- they don’t keep their colonies nice and neat like honeybees do, so you’d be likely to get a mouth full of bacteria or bee larvae in your honey if it came from a bumblebee.  But everyone thinks all bees make honey, and after all, honey is delicious.

2.) The social nature of bees.

The average person may not know much about solitary bees or the differences in the life cycles of bee species, but usually they can tell you that honeybees have a queen.  People also commonly know that the queen bee is responsible for producing all the rest of the bees, and that the rest of the bees in the colony will fight to the death to protect her.  I’m not trying to dive too deeply into psychology here, but I think that the apparent altruism of bees attracts people to them and makes them a more sympathetic organism than we would normally consider something with a sting.  People also like the concept of a “superorganism.”

3.) The “busy bee”

If you’ve ever watched a bee in the springtime foraging on a flower it’s clear that they are working hard.  The work ethic of bees is impressive!  I think people like that bees put in a hard day’s work, collecting food for themselves and their brood.  It makes us think kindly of them, the working class insect.

4.) The ecosystem service

Maybe my first three reasons seem a bit silly and have left you unconvinced, so I will end with a more scientific explanation.  We’ve known for some time that bees make excellent pollinators, and pollination is an important ecosystem service.  In 2006 Science published two studies describing declines in pollinators in Europe and North America.  These findings were compounded by the emergence of colony collapse disorder just a year or so later, leading to intense fear that our helpful honeybees were experiencing declines in population that they simply wouldn’t be able to recover from.  The next question was what will be the impact of declining bee populations on food security? Turns out it’s rather significant.  Studies have shown that the global economic value of pollination is over €153 billion.  Furthermore, a study in March demonstrated that honeybees cannot replace the value of pollination services from wild pollinators; we can’t just worry about the honeybees, wild bees are important to increasing yields as well.  Food security is not something we tend to take lightly, so our pollinators have intrinsic value.  This helps explain the incredible media coverage bees have been receiving lately, especially regarding the European ban of neonicotinoids, a class of insecticides that have been shown to be harmful to bees.

I wonder though, how many people know the facts about how important bees are to the ecosystem service of pollination and therefore food security?  How many people really like them because they are fuzzy, make sweet honey, and are hard workers?  I suppose you could argue that it doesn’t matter why people are attracted to bees, it’s positive regardless because it encourages money to be spent on research into why they are declining and how we can conserve their populations.  I think it’s helpful to try to understand why bees have become a sort of flagship species. That way we can better understand what traits cause humans to assign intrinsic value to organisms for future conservation work.

Author

Erin Jo Tiedeken: tiedekee[at]tcd.ie

Photo credit

wikimedia commons

Bees and biofuels….what’s the buzz?

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As oil prices sore and the future of world energy is uncertain, there is rising demand for alternatives to fossil fuels. From solar energy to wind to algae fuel and biodigestion, the alternatives are numerous. One alternative that has received substantial media attention is the use of bioenergy which involves the production of energy from crops including maize, sugarcane, elephant grass and oilseed rape which are grown specifically for energy purposes.

However, the debate over bioenergy crops is often heated. Do they compete with food crops and therefore increase prices in an already stretched market? Do bioenergy crops result in the destruction of tropical rainforest to clear new areas for farmland? And are bioenergy crops even carbon neutral to begin with?

One debate that has been investigated by researchers in Trinity as part of the Simbiosys project is whether bioenergy crops can have impacts on biodiversity – the animals and plants that live on and in farmland. Not only are these animals and plants an important part of our heritage, but they are the pollinators of our food crops, the insects that control agricultural pests and the organisms that help provide us with clean water and air. With two-thirds of Irelands land area used for farming, any changes in farming practice are likely to have knock-on impacts on biodiversity.

A study recently published in the Journal of Applied Ecology investigated how growing bioenergy crops impacts the bees and other pollinating insects that pollinate wild flowers, apples, berries, oilseed rape, clover and many other crops here in Ireland (in fact pollinators are required for approximately 1/3 of all the food we eat). It was found that although different types of insect responded differently, there were no decreases of pollinators in bioenergy crop fields in comparison to their conventional farming alternative. And for some pollinator groups such as the small solitary bees, the introduction of small amounts of different crops into agricultural areas may actually be beneficial.

However, bioenergy crops did not provide the stable nesting conditions needed for pollinators; almost all bumblebees chose to nest in the field margins and hedgerows surrounding the fields. Field margins and hedgerows also provided habitat for large numbers of other insects. The study concluded that small amounts of bioenergy production on existing farmland may provide a diversity of habitats for pollinating insects, but that changes in levels of production in the future may have different effects. Hedgerows and field margins should also be maintained during bioenergy production as they are important nesting and forage sites for pollinating insects.

Although bioenergy crops in their current form seem like good news for bees, the future may be less certain. Growing these crops over larger areas rather than in individual fields, or the replacement of forests or meadows rather than existing arable (tilled) land, may have very different effects. With EU targets of 20% energy from renewable sources by 2020, and bioenergy incentives for farmers, we can expect further changes in this developing sector over the next few years.

Author

stanleyd[at]@tcd.ie

Photo credit

Dara Stanley

The buzz on neonicotinoids

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On the 31st January, stimulated by a European Food Safety Authority report, the EU proposed banning three neonicotinoid insecticides which have been implicated in causing honeybee decline. These insecticides are widely-used, systemic (i.e. soluble enough in water to move around the plant’s vascular system to nearly all plant tissues), and, like nicotine, affect the insects’ central nervous system. They are highly effective at reducing insect pests that feed on crops and reduce yields and value, and many farmers are concerned about the effect the proposed ban will have on crop production. But these insecticides can also end up in the nectar and pollen of crops (as well as in the soil and in non-crop plants), and thus can have unintended side-effects on beneficial, nectar-feeding insects, who act as pollinators. Especially bees.

Bee decline has become a hot topic with scientists, the media, the public and even some politicians, but until recently the threat of neonicotinoids to bees has not been seriously implicated in their decline. Concern about pollinator decline is a result of the important role that pollinators play in food production: 75% of crop species depend on animal pollinators, which translates into 35% of global production; and the total annual economic value of pollination has been estimated at €153 billion globally. In addition, pollinators are fundamental to most terrestrial ecosystems, and indirectly affect the availability of food for other organisms (e.g. fruits and berries for frugivorous birds), as well as the structure and functioning of ecosystems.

So here’s the paradox: flower-visiting insects including bees are really important for agricultural production. But so is the use of neonicotinoid pesticides. Which is more important and is the ban justified on scientific grounds?

In the last year, the evidence that neonicotinoids have negative impacts on bees has been mounting. Bees and other flower-visiting insects are exposed to neonicotinoid pesticides in multiple ways: during planting of seeds which have been coated with pesticides as a pre-planting treatment, by collecting pollen and nectar from the crop, and by foraging on non-crop plants which take the pesticide up through the soil. Traditionally, toxicological tests of agrochemicals are carried out on the managed honeybee Apis mellifera, and pesticides are rated according to their lethal effects (by calculating the LD50 – the dose required to kill half the organisms tested after a specified duration). But the biology of Apis and all the other bee species (20,000 of them worldwide) is different. Can we generalise about effects on Apis, to effects on other bee species, and other pollinating insects including hoverflies and butterflies? And what about sub-lethal effects, i.e. those that don’t kill the insects, but affect their physiolology, behaviour and fitness?

Neonicotinoids are highly toxic to insects – that’s the whole point of them. Bees are insects. So it shouldn’t be too much of a shock that they kill bees. Last year it was shown that neonicotinoids can also have sub-lethal effects in honeybees, by decreasing foraging success and navigation by individuals back to the hive. At the same time, the neonicotinoid pesticide, imidacloprid, can reduce bumblebee colony growth and fitness by affecting their feeding behaviour. Some dissenters have cast doubt on the field-relevance of laboratory tests, claiming that field-realistic dosages have not been used, but this is not the case – the concentration of imidacloprid in oilseed rape flowers for example has been found to be 4.4-7.6 mg/kg in pollen and 0.6-0.8 mg/kg in nectar, which was within the range tested on bumblebees. This is pretty convincing evidence that neonicotinoids can cause very adverse effects on populations of these social bees.

Although neonicotinoids are not the only cause of widespread bee decline, they are more than likely contributing to it. Some of the agrochemical companies are claiming that bee decline has nothing to do with their chemicals and instead blame decline on Varroa destructor, the parasitic mite which infects honeybee colonies. Whilst Varroa probably plays its part in honeybee decline, the most probable cause of decline in other bee species is multiple pressures, including habitat loss and loss of forage plants, AND the use of neonicotinoid pesticides.

So should these insecticides be banned? YES, if we want to address pollinator decline. They should not be used for insect-pollinated crops, and wind-pollinated crops that insects forage on (including maize). But what’s the alternative for the farmer? How can crop production be maintained in the absence of these chemicals? Use something worse? If we’ve learned anything since Rachel Carson’s “Silent Spring” published 50 years ago last year, it’s that an alternative will be found, and we can’t be sure that this won’t be worse for the bees and other pollinating insects.

Author

Jane Stout: stoutj@tcd.ie

Photo credit

wikimedia commons