Natural Sciences at PROBE 2018: The pollinator bit

Each year, Trinity College Dublin takes part in European Researchers Night, funded by  European Commission Marie Skłodowska-Curie Actions, where research institutions around Europe open their doors to the public to promote their research. This year, Trinity’s event, PROBE, in collaboration with the Science Gallery, took place on Friday 29th September. Our research group led a morning activity as PhD student, Cian White explains below…

To kick-start the day, the Science Gallery welcomed 90 children from four different schools around Dublin to a hands-on workshop about pollinators. Prof. Jane Stout introduced the children to the amazing diversity of insect life (all 1.5 million species described so far) and was careful to remind them that spiders are not insects (why? Cus they have 8 legs silly!).  The children were quick to catch on though and in response to a question about why insects are special, hands shot up all over the room and in their eagerness, one shouted out ‘Cus they can fly!’. Spot on, I think we have a recruit for the plant animal interaction lab!

BeeBoard-768x431The children’s thoughts on bees.

After retelling the story of the Hungry Caterpillar, illustrating that metamorphosis allows many insects to occupy very different niches during their life (another reason why there is 1.5 million of them), Prof. Stout let them in on a little secret. Only a handful of bee species actually produce honey! Out of the 20,000 species of bee in the world! Gasps from the young audience, ‘There’s more than one species of bee?’. Recruit number 2. After showing the children how honey bees communicate to each other through dance (wish I could be a bee), it was onto the interactive part of the event. Three groups rotated around activities, from learning to dance like a bee, to live like a bee (making solitary bee hotels for the 15 Irish species who nest in cavities) and to eat like a bee (aka how dependent on pollinators is the food you eat?). My favourite reaction of the day: a girl finding out that the cocoa plant (where chocolate comes from) is pollinated by mosquitoes and swearing to never eat chocolate again. I wish her luck.

A luxury insect hotel
A luxury insect hotel

All in all it, was great fun and the children learned lots, and were genuinely enthusiastic about pollinators. Thanks to Sandra Austin and the trainee teachers from Marino, Irene and Elena for getting stuck in, Jane for being awesome and Kate for organising. For more information about Ireland’s 99 species of bee and 180 hoverfly species and what you can do to conserve them, check out

About the Author: Cian White is a PhD Student supervised by Prof. Jane Stout and Dr. Marcus Collier, and is a joint member of the Plant Animal Interactions and Urban Ecology labs. His research focuses on network, community and applied ecology. You can find out more about his research here: Cian White

This post originally formed part of the EcoEvo@TCD blog “From Worms to Wildfire: Natural Sciences at PROBE 2018” – check it out to find out what else we got up to on the night…


Pesticides harm bees, but what about hoverflies?

Summer has come to an end, and with it the hot, sunny days that we all enjoyed. It was a good year for field work, as the uncharacteristically warm Irish summer made my job of sampling for my research easier.

I am a PhD student with a research focus on aphidophagous syrphids in cereal crops. Syrphids are commonly known as hoverflies, many of which have colour patterns that mimic bees and wasps. I focus on the species with larvae that feed on aphids (aphidophagous), therefore providing pest control services to tillage farmers (Figure 1). The adults, however, generally feed on pollen and nectar from flowers, providing pollination services like the bees and wasps they mimic.

Figure 1: Hoverfly eggs (white) and aphids on oat leaves. These will hatch into larvae that will feed on the aphids. Image Credit: Sarah Gabel

However, just as bees are facing threats of habitat degradation, so too are hoverflies. This summer, I was investigating the presence of one threat in particular – pesticides. Although intended to be applied to a certain aspect of the landscape (e.g. crops) to kill a certain kind of pest (e.g. aphids), pesticides can disperse throughout the environment, ending up in unintended places (e.g. wildflowers near a treated crop) and harming beneficial wildlife (e.g. pest-controlling, pollinating hoverflies). An adult hoverfly can inadvertently consume pesticide residues that ended up in the pollen and nectar of wildflowers. Likewise, hoverfly larvae can feed on aphids that had been feeding on treated crops, therefore being exposed to the pesticides the aphids were either sprayed with or ate themselves. To determine whether pesticides could be found in these food resources for hoverflies – and in what amounts – I sampled aphids from cereal crops, and pollen and nectar from blackberry flowers (Rubus fruticosus, Figure 2) in the hedges surrounding the crops.

Figure 2: A blackberry flower loaded with pollen. Image Credit: Sarah Gabel

With an amazing team of helpers, the samples were all collected, and are safely stored in a freezer, waiting for chemical analysis. Surveying of the adult fauna found a high presence of aphidophagous hoverflies, with the highest counts going to the iconic marmalade hoverfly (Episyrphus balteatus, Figure 3).  While there weren’t many hoverfly juveniles found hunting for aphids on the crops, there were plenty of other predators feeding on aphids – ladybirds, parasitoid wasps, and spiders just to name a few. Pesticide residues found in aphids could have an impact on all of these beneficial predators, just as residues found in the nectar and pollen of blackberry flowers could have an impact on all the pollinators feeding on them.

Figure 3: The marmalade hoverfly, Episyrphus balteatus. Image Credit: Sarah Gabel

While this work is mainly focused on the poisons in hoverfly food resources (aphids, nectar and pollen), the results will have significant meaning to all beneficial wildlife that depend on these resources and, subsequently, will have meaning to us humans as recipients of their ecosystem services.


Sarah Gabel (@SarahG10J) is a PhD student at Trinity College Dublin supervised by Professors Jane Stout and Blanaid White at DCU. She is studying aphidophagous hoverflies in cereal crops, and their interactions with the landscape. Sarah’s PhD is funded by the Irish Research Council (IRC).


What’s the buzz about Irish honey?

Newly published research by IRC-funded PhD student, Saorla Kavanagh, from DCU, supervised by Blanaid White and Jane Stout, has hit the headlines today, with articles in The Irish Times, Independent, Irish Examiner, The Times, and RTE news,  and the TCD news page.

Saorla Kavanagh with her bees

By sampling honey from all over Ireland (see map below), we evaluated the physiochemical properties and total phenolic content (TPC) of single vs. multi-floral honey, and compared this with selected international honeys. The story that has hit the headlines is that Irish heather honey has similar total phenolic content as the famous manuka honey from New Zealand. Increased phenolic content has been linked with beneficial antioxidant effects, and manuka honey commands high retail prices due to its alleged health benefits.

Honey samples were donated by beekeepers from across Ireland

However, we only tested three heather and three manuka honey samples. Most of our samples (124) were multi-floral honeys, and we found that those produced by urban bees (55 samples) had a greater TPC than their rural counterparts (69 samples). We also analysed ivy honey for the first time.

Because the botanical origin of honey has the greatest influence on its phenolic content, the availability of food sources (flowers) in the wider landscape influences its potential health benefits. Finding a difference in honey chemistry between urban and rural hives probably reflects the difference in flower availability in urban and rural areas, and raises interesting questions with regards to floral availability and quality across landscapes.

The full paper is published in Food Chemistry.

We are grateful to the Irish Research Council for funding the research, and to the beekeepers across Ireland who donated honey samples.

The Flight of the Undergraduate – From Genetics to Bumblebees

My name is Maeve McCann and I’m a Genetics student at TCD. This summer I am working on a research project with Jane Stout (Botany, TCD) and Jim Carolan (Biology, Maynooth University). Last May (2017), I sent Jane an email asking if there was any chance I could get involved with the work she was doing with bumblebees, not even sure if as a 2nd year I would get a reply. However, to my delight Jane replied and here I am doing a research project and loving it!

In a meadow near Monawilkin Lake, Derrygonnelly, Co. Fermanagh
In a meadow near Monawilkin Lake, Derrygonnelly, Co. Fermanagh

The project Jane and I put together aims to further research already carried out on a group of bumblebees known as B. lucorum agg. They are a cryptic complex meaning that the worker bees of four different species are indistinguishable by appearance. They are all white tailed with two yellow bands, one on the thorax and one on the abdomen. The four species are Bombus terrestris, Bombus lucorum, Bombus magnus and Bombus cryptarum (B. terrestris queens are distinguished from the other queens by their buff tail, however the workers are generally not distinguishable). Due to their cryptic appearance the only way to exactly determine the species is to do a genetic fingerprint test from a sample of their DNA. This is a robust method for species determination and, provided I get the hang of the lab techniques, I should be able to figure out which of the four species are living in which habitats across our chosen locations of County Fermanagh and Dublin city (cross-border bees!).

Two yellow stripes and a white tail, but which species?

To get the DNA samples I was out “in the field” for a few weeks in Dublin and Fermanagh catching Bombus lucorum agg bees. I only need a single tarsal (foot) sample from each bee as this gives sufficient DNA to run the fingerprint test. I have had a fantastic time out and about catching bees to get the tarsal samples. I have learned so much about bumblebees, been to beautiful places and had great conversations with people enthusiastic about bees. I also managed to drag a few friends and family along with me. I took a few friends to the flower beds in Phoenix park, went with a group learning about Bumblebees with Bí Urban around Stoneybatter, went cycling between meadows in west Fermanagh with my Mum and canoeing to islands in Lower Lough Erne with my Dad. I’ve also been working on my farmers tan having been out and about during the recent hot weather!

blog pic 2
On the way to Inis Davar, Lower Lough Erne, Co. Fermanagh.

Having completed my fieldwork I feel enriched with the new knowledge which it has brought. I’ve seen brand new things, learned a lot about bumblebees and gained a whole new appreciation for the insect world, but I have also come to realise that bumblebees along with many other insect species are under major threat from human activity. With projects like the All-Ireland Pollinator Plan in full swing I have great hope that we can turn the tide of habitat loss and insect decline.

As for me – It’s now time for me to take all my samples to Jim Carolan’s lab in Maynooth and discover what I have caught. So I’m switching my net for a pipette.


Maeve McCann is an undergraduate Science student at Trinity College Dublin, and her project is supported by the C.B. Dennis British Beekeepers’ Research Trust.

PROTECTS (Protecting Terrestrial Ecosystems Through Sustainable Pesticide Use)

We have received funding from the Irish Department of Agriculture, Food and the Marine (DAFM) under their Research Funding programme for a new project called PROTECTS. We will provide baseline information in an Irish context to build towards mitigating the effects of pesticide use on terrestrial ecosystem services, focussing on pollinators and soils.


This project brings together several of the members of the Irish Pollinator Research Network (IPRN) and is an interdisciplinary, multi-institutional 4-year project, starting 1st July 2018.

Dara Stanley (UCD) will lead the project, which involves researchers from Trinity College Dublin (Jane Stout), Maynooth University (Jim Carolan), Dublin City University (Blanaid White), and Teagasc (Karl Richards). Our findings will help to ensure that pesticides can be used safely while protecting wildlife, health and the environment, both in Ireland and internationally.

There are two PhD studentships currently available at TCD and DCU (details below). Successful candidates will join two other PhD students on the project team.

TCD studentship: Characterising pesticide residues in floral resources for bees

In this PhD project, the potential for pesticide contamination of floral resources as a result of translocation from soil will be evaluated. This translocation to floral products poses a major route of exposure of pollinators to pesticides. Working with other members of the PROTECTS team, we will identify four systemic pesticides which are a) extensively in Irish agricultural systems and b) potentially have negative impacts on pollinating insects. We will develop and validate extraction protocols for these pesticides from the floral resource matrices of nectar and pollen, collect samples from model species from field sites, complete laboratory-based chemical analyses and determine residue presence/concentrations in nectar and pollen to compare with soil-level contamination. In addition, methods for screening residues from nectar and pollen samples for rapid assessment of toxicity of floral rewards will be developed, and nectar extracts will be utilised directly in bee exposure experiments.

DCU studentship: Developing tools for pesticide detection and toxicity testing in soils and floral resources for bees

In this PhD project, we will collect soil samples from sites across Ireland and characterise these soils in terms of their physical and chemical properties, and their microbial communities. We will develop methods to extract pesticide residues from these soils, and analyse these extracts using GC-MS and HPLC-MS methodologies to determine which pesticide residues are present, and at what concentration. The extracted pesticide residues will also be used to determine their impact on pollinator species. We will also use the developed analytical tools to determine what pesticide residues are present in associated floral resource matrices for bees, in particular nectar and pollen. Finally, we will also develop a soil toxicity biosensor and apply this to screen the soil extracts.