Uncategorized – Ecology Field Notes

Glasgow (Wild)Life

It has been a whirlwind few months. In March 2026, I moved from London to Glasgow to take up a new role at Glasgow Museums as Collections Officer (Biological Data). I’ve been very excited about taking on the role where I am now responsible for managing the Glasgow Museums Biological Records Centre, through collating, validating, and verifying biological data for the Glasgow City Region (covering 8 local authorities).

This also means that I will be working closely with data providers such as recording schemes and societies, Biodiversity Officers, Coutryside Rangers, environmental organisations, and members of the public to keep the database up-to-date. With over 1.3 million records currently held in the database and with growth expected to be around 50,000 new records per year, this is no mean feat. For my first few months in post, I have been familiarising myself with the database and getting to grips with not only a new city and a new country, but also new software systems. It has been a very steep learning curve, and I am very grateful to everyone who has helped out with Recorder 6 queries, field excursions, and introductions to all the right people.

Glasgow Museums Resource Centre. My new office space on the outskirts of Glasgow.

Over the last couple of weeks, my focus shifted from database management to prioritising the delivery of commercial enquiries. The previous pricing structure and commercial offer have been updated so that they are now in line with other Local Environmental Records Centres. This phase of the job is all customer-focused. I have been running some explorative searches from the database and will be meeting with multiple stakeholders to discuss how these data can be used for planning, conservation, research, and public engagement.

In relooking at the offer, I also realised that some of the workflows could be streamlined through using the R programming language and have been working on coding scripts for reporting functions and managing queries.

When not at my desk and behind a screen, I have been getting out to visit green spaces in and around Glasgow with Richard Sutcliffe’s excellent (though sadly now somewhat out of date) guidebook as reference. I have only scratched the surface of all the places to visit, but I have been struck by the clear ecological differences between the Scottish lowlands and Southeast England. The climate is obviously cooler and wetter here, and with very different geology as well, come different habitats and therefore different invertebrate species and assemblages.

I’m still figuring all this out, but it does mean that I can fairly easily find new lifers when I’m out in the field (or on a lunch break). And, as climate change effects are causing Northward range shifts in invertebrate species, it is also possible to find species newly arrived in the area.

Gorse Orbweb Spider (*Agalenatea redii)*

Four-spotted Carrion Beetle
(*Dendroxena quadrimaculata*)

I’m planning a short trip back to London soon, but am so pleased with the new job and am excited to see where my Scottish adventure leads.

Cody Dock Ecology Update

It’s been 9 months since I started my role as Biodiversity Officer at Cody Dock and it’s been a rather busy time. I wanted to review some of the work that has been done here, summarising parts of the excellent Tidal Lea Ecology Report prepared by my predecessors & adding what we’ve already managed to build on this with our Community Science and Conservation Volunteers in a concise manner.

Moving on

From February 2023, I will be taking on the role of Biodiversity Officer for the Gasworks Dock Partnership charity based at Cody Dock on the tidal stretch of the River Lea in east London. I will be co-ordinating volunteer opportunities for surveying and monitoring habitats and wildlife of the local area and delivering related training to our network of community scientists.

Not exclusively focused on invertebrates (though you can be guaranteed they will feature heavily) the monitoring will continue the existing bird counts, bat walks, and vegetation surveys that have been carried out so far – there is an excellent report available that covers this for 2021-2022. Plans are afoot to add in Flower-Insect Timed Counts to contribute to the UK Pollinator Monitoring Scheme and various other invertebrate recording schemes.

Habitat management and improvement works will also be part of this job where establishing new reed beds in the Lea will create cover for water birds and serve as a natural filter for some of the litter and pollutants in the river. Silt traps have already been set along the sloped concrete banks and have become vegetated, and we hope to be able to extend this work further along the east bank. Additionally, there are other areas on or near the industrial estate that can be better managed for wildlife and people including woodland, scrub, and parkland which will entail a number of different projects.

Canary Wharf as seen from the Cody Wilds walk along the east bank of the River Lea.

My vision for this stretch of the Lea is that it acts as a green and blue corridor through this part of east London which has a very industrial heritage, but which is now rapidly being redeveloped with high-density housing. The river serves as the boundary between the boroughs of Newham and Tower Hamlets. These are already densely populated areas (Tower Hamlets has the highest density per km of all English districts, while Newham has the 4^th highest population of all the London boroughs) with high levels of poverty (Tower Hamlets has the highest poverty rates in London with Newham ranking 3^rd highest). Consulting with property developers at sites in both boroughs to offset some of the habitat loss caused by building apartment blocks as well as helping to shape a nature-friendly approach to the landscaping will also be part of the job. The loss of post-industrial brownfield sites to development is of concern and we will be working to try to mitigate this through the establishment of green roof systems that mimic traditional brownfield habitat as well as advising on the best use of pocket parks and identifying areas to be set aside as wilder habitats.

Bromley-by-Bow Gasworks which is a classic example of the open mosaic habitats of post-industrial brownfield sites in the area which are being redeveloped into high-density housing.

In other news, I recently took on the role of Woodlouse Recorder for the London Natural History Society with plans to increase records for this group so that we can have a better understanding of their distribution across London. So come along to Invertebrate Field Recorder Days across London and Invertebrate Study Days at the Natural History Museum to learn more about these fascinating crustaceans. I have also recently been elected as a trustee for Bethnal Green Nature Reserve where I will be focused on helping with community-led ecology projects.

Working as FSC BioLinks Project Officer has been a fantastic experience. Some of my highlights over the past year-and-a-bit have been my reintroduction to aquatic invertebrates after spending such a long time focussing on all things terrestrial – there is so much to see underwater, and you get to have a bit of splash about which is especially fun on a hot Summer’s day. Formalising my self-taught ant ID with a number of courses (some of which I even got to teach!) and running my version of an Ant Picnic at Richmond Park where I got youngsters to do science while looking at ants. Rediscovering woodlice, millipedes and centipedes; finding the Downland Villa Bee-fly, Villa cingulata, in abundance at Bushy Park; visiting so many amazing sites in and around London from hidden gems to publicly accessible thoroughfares – the list goes on and on.

Downland Villa Bee-fly (*Villa cingulata*) from Bushy Park in the summer of 2022.

It has been fun and an absolute privilege to work across so many different invertebrate taxa. I recently presented some of the findings from the project at the BioLinks Legacy Conference (the final report will be made available to the public in due course) at the Wellcome Collection in London and am very proud of the work that our team managed to accomplish despite a global pandemic in the middle of our project delivery.

Slide from my presentation at the BioLinks Legacy Conference on 20 January 2023 showing the breakdown of all BioLinks place-based course delivery by invertebrate taxonomic group.

I have learned so much more about a wide variety of invertebrates from national experts (further improving my ID skills) and came to meet a community of people who are passionate, enthusiastic, generous, and knowledgeable about our natural world and the invertebrates upon which we all rely. My sincere thanks to every person who I’ve met along the way and I very much look forward to seeing and working with many of them again in the future.

Slavers, Rebels, and Regicide: The Fantastical Lives of Ants

I recently wrote a blog post for the FSC BioLinks project on some of the colony founding techniques and behavioural adaptations that have evolved in some ant groups and species. The blog post was entitled The Fantastical Lives of Ants: Slavers, Rebels, and Regicide, but I think I prefer the inversion of the title and subtitle as used above.

The piece was written in response to a comment made by an attendee at one of the Learn to Love Ants courses that I was teaching, where the person remarked that the lives of ants seem much like the fantasy series Game of Thrones. And there are certainly parallels that can be drawn between some of the observed behaviours of ants and the tropes of deception, brutality, conquest, and conflict that are rife in the fantasy genre.

There is of course much more complexity in these social insect societies than just these cherry-picked sensationalist topics, such as: brood care; mutualistic interactions with other organsims; the recently documented care for injured Matabele ants by their sisters; and many more besides. After all, as Sansa Stark says: “I’m sure cutting off heads is very satisfying, but that’s not the way you get people to work together”.

British Biodiversity in Peril

In the run up to both COP 26 and COP 15 many newspapers recently reported the shocking fact that Britain has lost almost half (47%) of its biodiversity since the industrial revolution. For naturalists and conservationists working in the UK this will,however, come as absolutely no surprise whatsoever.

Research by Prof Andy Purvis from the Natural History Museum in London showed that Britain is one of the most nature-depleted nations in the world, well below the global average of 75%. With the publication of the Biodiversity Intactness Index (BII) we can now clearly see in the data what naturalists have been warning about for decades from their field observations – Britain’s biodiversity is in peril.

What’s the deal with biodiversity anyway?

‘…Biodiveristy provides us with the food we eat, from the micro-organisms that enrich the soil where we grow our crops, to the pollinators who give us fruit and nuts… [and] many of our medicines originate from plants and fungi…’.
Sir Richard Attenborough

This beautiful animation (below) narrated by Sir David Attenborough and produced by The Royal Society explains the importance of biodiversity, both to us and the world at large.

When 67% of the UK is used for agriculture and a further 8% is built on that leaves a paltry and dwindling 25% for nature. According to official statistics from the Ministry of Housing, Communities and Local Government (2018), forest, open land and water constitute 21% of all land use in England.

‘As Presidents of COP26, the UK has put nature at the heart of the agenda, and we very much welcome this important study which highlights the crucial connections between climate and biodiversity and the urgent need to protect nature’.
Lord Zac Goldsmith, UK Government Minister for Pacific & the Environment

Damningly though, researchers from the RSPB have found that although 28% of UK land is reported by the UK government to be protected, only 11.4% of land area actually falls within protected areas designated primarily for nature conservation. And because of the poor condition of some of these areas, as little as 4.9% of UK land area may in reality be effectively protected for nature.

How do we effectively address this issue in Britain?

‘Governments possess the power – economic, political and legal – to address the planetary emergency, and there may still be time, but they must act now.’
Prof Andy Purvis, Natural History Museum

The British Ecological Society produced a report in May this year (2021) that called for a nature-based approach to tackling both climate change and biodiversity loss in conjunction with other climate and conservation actions. A brief summary of their specific policy recommendations provide examples of opportunities across a range of habitats through:

Restoring degraded peatlands and end burning on blanket bogs
Increasing native woodland and woodland connectivity in the right places
Establishing more saltmarshes
Protecting and re-establishing hedegrows in arable landscapes
Increasing agroforestry in arable landscapes
Increasing urban green spaces with a focus on native species

Unfortunately, any and all action to prevent further biodiversity loss is costly. A recent report from the Green Finance Institute claims that the UK governement faces as much as a £97 billion funding gap for its current commitments to nature-based actions over the next 10 years.

Regardless of the financial costs of mitigating and remedying biodiversity loss, we should never lose sight of the costs of inaction – not just economic, though these are significant. But also the legacy of a pillaged, spoiled and empty landscape; a depauperate and diminished native biota; and ultimately, an impoverished and increasingly precarious society.

What have I learned during my PhD?

Instead of attending an in-person seminar this year, PhD students in our department at UCL were recently asked to produce a video in response to a question set by the Post-graduate Tutors.

This is my video responding to the question: “What have I learned (so far) during my PhD?”.

Buzzkill: Arabica coffee plantations under increasing threat from the effects of climate change

Note that this content is from an article I wrote as part of my BSc degree in 2014. The latest reports indicate that coffee production and consumption have both increased since the slump of 2013 – 2016, while prices have shown a downward trend. Despite this, I think that the article remains relevant especially concerning coffee production and means of mitigating the inevitable effects of climate change.

Originating in the horn of Africa with cultivation possibly starting in Yemen around six
centuries ago, coffee is now one of the most popular hot drinks worldwide1. After oil, coffee is the world’s second-most traded commodity with 93.4 million bags, worth a staggering US $15.4 billion (£9.27 billion) exported from coffee-growing countries in 2009/2010. Now it seems that the world’s coffee-producing regions may be under threat from the effects of climate change, according to Aaron Davis and Justin Moat from Kew.

Screenshot 2018-09-29 at 11.44.31.png

By all accounts, we love our coffee, with nearly a third of the world’s population drinking it. The USA imported almost 27 million bags between November 2012 and October 2013 while the UK imported around 4 million bags over the same period, according to the International Coffee Organization (ICO). In total, worldwide imports for the 2012/2013 coffee season were an astonishing 133.9 million bags.

Reduction in productivity, increased and intensified management, and crop failure.

Of the 125 species of coffee plants found naturally, the two main types used in the production of coffee are arabica and robusta. Originally from the high-altitude, humid evergreen forests of Ethiopia and South Sudan, arabica is known to be climate sensitive with an ideal average temperature of between 18°C and 23°C and well-defined rainy and dry seasons. Arabica coffee is now grown in 52 countries worldwide. Robusta, as its name implies, is more comfortable with higher temperatures and produces a greater crop yield than arabica. With its higher caffeine content and more bitter flavour, robusta tends to be used in instant coffees while arabica is considered superior in quality and taste making up 70% of all commercially produced coffee. There are now thought to be around 26 million people working in the coffee sector worldwide. Our demand for coffee has never been greater and yet a series of climate-linked and interrelated problems such as increased temperature, unpredictable rainfall, the spread of insect pests and diseases, intensive farming, and urbanization could spell the end of coffee as we know it.

It’s getting hotter

Ethiopia (the fifth largest global exporter of coffee and Africa’s main coffee-producing nation) was used as an example by Davis and Moat when they looked at the possible future distribution of arabica coffee. They based their findings on the Intergovernmental Panel on Climate Change’s (IPCC’s) best estimates of anticipated temperature rises of 1.8°C to 4°C in global temperatures by the end of the twenty-first century and found that coffee production was likely to decrease significantly. Worryingly, they also found that there would be less land that is suitable for growing coffee, saying that it would lead “…to a reduction in productivity, increased and intensified management…and crop failure.”

Countries whose economies depend heavily on agriculture for their development may be hardest hit by a change in climate.

Responding to warming temperatures, some farmers are starting to grow their crops further up hillsides and mountain slopes. At higher elevations, where the temperature is slightly cooler, the arabica plants thrive once again. It is, however, harder to farm at higher altitudes and we cannot keep going up the mountains, we’ll simply run out of farmable land. There is also expected to be a climatic shift in latitudes so that the tropics and subtropics effectively move away from the equator, but this is incredibly difficult to predict because of air currents, ocean currents and local geography all affect this and act on one another. In a report by the International Trade Centre (ITC) entitled ‘Climate Change and the Coffee Industry’ the authors note that any shift in altitude or latitude may adversely affect the quality of the coffee and fewer parts of the world may end up being able to support arabica coffee production.

Unpredictable rainfall

As air and ocean temperatures rise, it is likely that wet areas will get wetter and dry areas will get drier according to both the ITC and IPCC. This is the rule-of-thumb measure for regions, but there is also expected to be far more variability; that is, more extreme droughts and more heavy rainfall. The increased warming will mean that for every 1°C increase in temperature the plants and animals that live in a certain area because the climate conditions are perfect for them there will have to shift by 160 km (about the distance between Birmingham and London as the crow flies) north or south, following those perfect conditions. In the case of some island nations a 160 km shift could be catastrophic. We should expect more humidity and higher rainfall to accompany the hotter tem- peratures. The seasonal and geographical rainfall and temperature patterns that we have all grown used to will change because of these shifts. This is of course incredibly bad news for arabica which needs quite particular weather conditions.

Intensive farming methods

The way in which the coffee is grown can also contribute to some difficulties. Traditionally, coffee was grown under taller trees and shrubs of different heights with a large mix of plant species. This meant that the coffee plants grew in shade and that the soil was rich with the nutrients of all of the accumulated dead plant matter. On a number of farms this method of growing has been abandoned in favour of plantation-style planting which means that the farmer can squeeze more plants into an area and improve the size of the yield. This involves clearing the land by chopping down the trees, sometimes burning, and planting sun-resistant varieties of coffee that have been bred to tolerate growing in direct sunshine. This intense planting regime also requires the addition of many tonnes of expensive man-made fertilizers and chemical controls such as fungicides and pesticides every year. These changes in production practices have been found to exacerbate the problems associated with coffee-growing according to Juliana Jaramillo, from the Institute of Plant Diseases and Plant Protection, at the University of Hannover in Germany. Studying a coffee-producing area near Nairobi in Kenya, Jaramillo and her colleagues found that open plantations were 2°C higher than shaded ones. Obviously, the associated warmer temperatures are a problem for arabica growing, but it can also present coffee-growers with a whole new set of problems. The increased exposure to heavy rain can lead to nutrients being leached out of the soil, soil conditions quickly deteriorate leading to soil erosion, and in the worst cases, water run-off that turns into floods and landslides. This becomes a cyclical problem, as crops fail or yields decrease, more intensification occurs to make up the shortfall and worsens the conditions.

The spread of insect pests & diseases

As with any crop plant, coffee can suffer from attacks by insect pests and diseases. With even small temperature rises and changes in rainfall patterns, these pests and diseases become more common and more difficult to control. The coffee berry borer beetle is the most destructive pest of commercially grown coffee, causing crop losses of more than US $500 million (£300 million) per year. These beetles actually benefit from increases in temperature. Based on a 1°C temperature rise over the next 50 years, Jaramillo expects to find the beetles reproducing faster and spreading further. Even now the insects are being found 300 metres higher up the slopes of Mt. Kilimanjaro in Tanzania than where they used to be ten years ago.

A devastating outbreak of coffee leaf rust in Central America was reported by Reuters News Agency in July 2013. The rust is very damaging to crop yields and was responsible for a 15% drop in production from the region last season with even worse effects expected for 2013/2014. Warm temperatures and high humidity are ideal conditions for the rust to spread, but it also needs the leaf that it is colonising to be wet to be able to first become established. Increased warming and heavier than usual rainfall in the region has created the perfect incubator for the rust. Ironically, another fungus, the white halo fungus, which attacks and partially controls the spread of the rust
has been wiped out by the systematic spraying of chemicals. “What we feel has been happening is that gradually the integrity of this once-complicated ecosystem has been slowly breaking down, which is what happens when you try to grow coffee like corn,” said US ecologist John Vandermeer.

The integrity of this once- complicated ecosystem has been slowly breaking down.

Rather than responding to temperature rises, the coffee white stem borer beetle, a major coffee pest in Zimbabwe, is becoming more common because of changes in rainfall. Adult beetles emerge from the infested coffee plants in the rainy season and with increased periods of rainfall up to 200% more beetles are expected there by the year 2080 says Dumisani Kutywayo and colleagues from the Coffee Research Institute (CRI). A quarter of Zimbabwe’s yield losses are due to infestation by coffee white stem borer and as rainfall patterns become more unpredictable and seasonality shifts, coffee farmers’ outlook can only be described as gloomy.

What is to be done?

In the face of catastrophe, all is not lost. The planting of coffee plants under a mixed canopy of plants has shown time and again to be a very effective model for controlling temperature. This form of planting is known as agroforestry and apart from creating more favourable conditions for coffee growing also allows the farmer to grow an additional crop such as bananas. This model is already in use across the coffee-growing world and as Helton Nonato de Souza from the Department of Soil Quality, Wagenin- gen University in The Netherlands explains: agroforestry creates shade, maintains a cooler air temperature, improves the condition of the soil, retains soil moisture, and limits damage from high rainfall. In their study area in the Brazilian Atlantic Rainforest, de Souza and his team also identified not only a vast array of tree species average of 60% greater biodiversity than the surrounding forests.

This species richness is an invaluable part of a healthy ecosystem and contributes to the well being of the coffee plants through biological controls. Pests and diseases can be controlled by their natural predators instead of chemicals as long as we provide a space for them to live according to the US ecologist, Daniel Karp.

There is also ongoing research into developing new breeds of arabicas that are less heat-sensitive or show more resistance to pathogens and diseases. Returning to the birthplace of coffee; some coffee plants with resistance to extremes in temperature have recently been found in the Ethio- pian Great Rift Valley.

90% of all coffee production is located in the developing world.

Screenshot 2018-09-29 at 11.47.33.png All the signs regarding arabica coffee growing in an age of global climate change are troubling. We must expect that production will probably decrease, that quality may be affected, prices will rise, and that the livelihoods of millions of people are at risk. With many farmers finding conditions more difficult with less income, there is the real risk that intense production of higher-income cane sugar, palm oil, cocoa leaf or khat replace coffee. What is needed is a reevaluation of the pricing structure of coffee linked to new patterns of behaviour that value the wider natural system within which it is grown. With the fair financial support of consumers, coffee farmers will be able to take steps to protect their livelihoods from the devastations of unpredictable rainfall, increasing temperatures and the growing abundance of pests and diseases. There is now an opportunity for more farmers to embrace small-scale, shade-grown coffees that will benefit the wider environment, keep their businesses sustainable and keep producing good quality coffees.

As a Roaster from a coffee company in London said in an interview for this article: “The consumers have the knowledge, the power and the resources to do something proactive. If the consumer is willing to pay more from an ethical company … then the farmers have the resource to invest in strategies that will help to mitigate the issue [of climate change].

References:

Kew Royal Botanical Gardens http://www.kew.org/plants-fungi/Coffea-arabica.htm Last accessed 04/03/142

International Coffee Organization http://www.ico.org/prices/m1.htm Last accessed 01/03/14

Davis AP, Gole TW, Baena S, Moat J (2012) “The Impact of Climate Change on Indigenous Arabica Coffee (Coffea arabica): Predicting Future Trends and Identifying Priorities.” PLoS ONE 7(11): e47981. doi:10.1371/journal.pone.0047981

US Department of Agriculture (2013) “Coffee: World Markets and Trade”http://apps.fas.usda.gov/psdonline/circulars/coffee.pdf Last accessed 22/02/14

Kasterina A, Scholer M, and van Hilten HJ. (2010) “Climate Change and the Coffee Industry.” International Trade Centre http://www.intracen.org/uploadedFiles/intracenorg/Content/Exporters/Sectoral_Information/Agricultural_Products/Organic_Prod ucts/Climate-Coffee-Ch-13-MS-ID-3-2-2010ff_1.pdf

Wexler A. “Arabica-Coffee Prices Climb to 16-Month Highs.” Wall Street Journal 19/02/2014http://online.wsj.com/news/articles/SB10001424052702303775504579392853470572772 Last accessed 26/02/14

Jaramillo J, Setamou M, Muchugu E, Chabi-Olaye A, Jaramillo A, et al. (2013) “Climate Change or Urbanization? Impacts on a Traditional Coffee Production System in East Africa over the Last 80 Years.” PLoS ONE 8(1): e51815. doi:10.1371/journal.pone.0051815

Kutywayo D, Chemura A, Kusena W, Chidoko P, and Mahoya C. (2013) “The Impact of Climate Change on the Potential Distribution of Agricultural Pests: The Case of the Coffee White Stem Borer (Monochamus leuconotus P.) in Zimbabwe.” PLoS ONE 8(8): e73432. doi:10.1371/journal.pone.0073432

de Souza HN, de Goede RGM, Brussaard L, Cardoso IM, Duarte EMG, Fernandes RBA, Gomes LC, and Pulleman MM. (2012) “Protective shade, tree diversity and soil properties in coffee agroforestry systems in the Atlantic Rainforest biome.” Agriculture, Ecosystems and Environment. 146, 179-196

Jaramillo J, Muchugu E, Vega FE, Davis A, Borgemeister C, et al. (2011) “Some Like It Hot: The Influence and Implications of Climate Change on Coffee Berry Borer (Hypothenemus hampei) and Coffee Production in East Africa.” PLoS ONE 6(9): e24528. doi:10.1371/journal.pone.0024528

Nicholson M. “Central American coffee leaf rust sends roasters to new markets for beans.” Reuters News Agency 10/07/2013http://www.reuters.com/article/2013/07/10/coffee-fungus-supply-idUSL2N0EV20S20130710 Last accessed 01/03/14

Jackson D, Skillman J, and Vandermeer J. (2012) “Indirect biological control of the coffee leaf rust, Hemileia vastatrix, by the entomogenous fungus Lecanicillium lecanii in a complex coffee agroecosystem.” Biological Control. 61:1, 89-97

Erickson J. “Modern growing methods may be culprit of ‘coffee rust’ fungal outbreak.” Michigan News: University of Michigan. 12/02/2013http://www.ns.umich.edu/new/releases/21192-modern-growing-methods-may-be-culprit-of-coffee-rust-fungal-outbreak

Karp DS, Mendenhall CD, Sandi RF, Chaumont N, Ehrlich PR, Hadly EA, Daily GC. (2013) “Forest bolsters bird abundance, pest control and coffee yield.” Ecology Letters. 16:11, 1339-1347

Gonthier DJ, Ennis KK, Philpott SM, Vandermeer J, and Perfecto, I. (2013) “Ants defend coffee from berry borer colonization.” BioControl: Journal of the International Organization for Biological Control. 58:6, 815-820

The Walking (Un)Dead: Zombie ants and the strange effects of parasitic fungi on ant behaviour.

In the understorey of a tropical forest, a carpenter ant, of the species Camponotus leonardi, has descended from the canopy away from her regular foraging trails and staggers drunkenly along a branch. Her movements are jerky and conspicuous. She twitchily moves forwards and suddenly starts convulsing with such ferocity that she falls from the branch onto the ground before again taking up an erratic fitful path that zigzags and circles back on itself. Around noon, after several hours of climbing and aimless lurching (now no more than about twenty-five centimetres above the ground) the ant finds herself on the underside of a sapling leaf where, without warning, she forcefully sinks her mandibles into one of the leaf’s veins, gripping it firmly between her tightly locked jaws. Within six hours the ant is dead. After two days, white hairs bristle from between her joints and a few days later these have become a brown mat covering the whole insect and a pinkish-white stalk has started to erupt from the base of the ant’s head. The stalk continues to grow and within two weeks it has reached twice the length of the ant’s body reaching towards the ground below.

This is a description of a “zombie-ant”, part of the life-cycle of a parasitic fungus, Ophiocordyceps unilateralis. This bizarre behaviour was first recorded by Alfred Russell Wallace in Sulawesi in 1859, but was not researched in much detail until quite recently. It has since been discovered that the fungus disrupts the normal behaviour of the ant through chemical interference in the brain, causing the infected ant to behave in ways that will improve the fungus’ opportunities to spread its spores and so reproduce. The fungus grows throughout the body cavity of the ant, using internal organs as food while the ant’s strong chitonous exoskeleton serves as a kind of capsule, protecting the fungus from drying out, being eaten, or further infection.

The earliest known record of a fungus visibly parasitizing an insect dates from about 105 million years ago, it is a male scale insect, preserved in amber, with two fungal stalks projecting from its head. But this fossil cannot tell us if the infected insect’s regular behaviour was changed or disrupted in any way. Evidence of “Zombie-ant” behaviour dates from around 48 million years ago from fossilised leaves that show the distinct markings on either side of leaf veins left by the lock-jawed mandibles of Eocene epoch ants. This association is evidently ancient and seemingly very common, with about 1,000 species of fungal parasites of insects known to exist today. These fungal pathogens have evolved to become either strictly species-specific or more generalist in their target insects, with some able to infect hundreds of different species. The variety of fungal pathogens and potential hosts has created some peculiar behaviours in insects which have most likely co-evolved with the fungi.

It is sometimes difficult to know which of these insect behaviours are entirely involuntary and driven by the fungus to improve its own reproductive success; and which the insects have evolved as a form of defence against infection. One of these unresolved odd behaviours is when the ant host climbs to an elevated position in what is known as “summit disease”. This increases the area over which spores can spread through wind dispersal, and removes the ant from close proximity with its colony or relatives. It is unclear if this behaviour is a zombie state caused by the fungus or if it is an altruistic act of self-sacrifice by the ant. By moving to an area away from its relatives it might be saving the rest of the colony from the immediate spread of infection by what is sometimes called “adaptive suicide”.

In this age-old struggle for survival the ants have developed adaptations to protect themselves and their nests from fungal infections. Grooming themselves and socially cleaning each other, allogrooming, they remove potentially harmful spores before these can penetrate the cuticle and take hold. Some ants spray poison in their nests to act as fungicides and if that fails to stop an infestation, they partition their nests by sealing off contaminated chambers. In some cases infected individuals are carried out of the nest by healthy workers; and as a last resort the entire colony relocates, abandoning the nest.

Zombie-like behaviour in insects is also caused by other types of parasites including bacteria and even other invertebrates. Such parasites are extreme versions of the multitudes of microscopic organisms that exist in and on all living things. This raises fascinating questions about the nature of any organism’s true independence in what are undoubtedly highly complex interrelated living systems. Zombie-ants provide us with a glimpse into this intricately tangled-web of molecular influences and behavioural adaptations – often leading us to wonder: who, ultimately, controls whom?

References:

Andersen, S.B., Gerritsma, S., Yusah, K.M., Mayntz, D., Hywel-Jones, N.L., Billen, J., Boomsma, J.J. and Hughes, D.P. (2009) The Life of a Dead Ant: The Expression of an Adaptive Extended Phenotype. The American Naturalist, 174(3): 424-433.

Hughes, D.P, Andersen, S.B., Hywel-Jones N.L., Himaman W., Billen, J. and Boomsma J.J. (2011) Behavioral Mechanisms and Morphological Symptoms of Zombie Ants Dying from Fungal Infection. BioMed Central: Ecology, 11(13).

Pontoppidan M.-B., Himaman W., Hywel-Jones N.L., Boomsma J.J. and Hughes D.P. (2009) Graveyards on the Move: The Spatio-Temporal Distribution of Dead Ophiocordyceps-Infected Ants. Public Library of Science: ONE, 4(3): e4835.

Shang, Y., Feng, P. and Wang, C. (2015) Fungi That Infect Insects: Altering Host Behaviour and Beyond. Public Library of Sciences: Pathogens, 11(8): e1005037

Hughes, D.P., Wappler, T. and Labandeira C.C. (2010) Ancient death-grip leaf scars reveal ant–fungal parasitism. Biology Letters, 7: 67-70.

Roy, H.E., Steinkraus, D.C., Eilenberg, J., Hajek, A.E. and Pell, J.K. (2006) Bizarre Interactions and Endgames: Entomopathogenic Fungi and Their Arthropod Hosts. Annual Review of Entomology, 51: 331-57

Bekker, C. de, Quevillon, L.E., Smith, P.B., Fleming, K.R., Ghosh, D., Patterson, A.D. and Hughes, D.P. (2014) Species-Specific Ant Brain Manipulation by a Specialized Fungal Parasite. BioMed Central: Evolutionary Biology, 14(166).

Faking it as a survival strategy

Cheats and Deceits: How animals and plants exploit and mislead. By Martin Stevens. Published by Oxford University Press (2016).

Last year, on a trip to Devon, I saw my first ever oil beetle (Meloe proscarabaeus). She was beautiful. Her black carapace glistened violet and blue in the sunlight. She was gravid and crawling along the footpath in search of a place to dig a nest burrow to lay her eggs. But what I did not yet appreciate was the extraordinary life cycle of these captivating beetles. The young of a related species, Meloe franciscanus, emerge from the nest and swarm up a nearby plant where they congregate in a mass mimicking the shape of a female solitary bee (Habropoda pallida) and release a chemical compound similar to the bee’s sexual pheromones. This proves all too irresistible to male bees who are drawn to this aggregation and attempt to mate with it, presenting the larvae with the perfect opportunity to grab hold of the bee and clamber onto his back. He then carries these passengers with him until he finds a female to mate with at which point the larvae instantly decamp onto the female. From here they then transfer to her nest where they devour the stored nectar, pollen and the bee’s eggs. The evolution of this complex mimicry is absolutely fascinating and forms part of Martin Stevens‘ interrogation of deception in Cheats and Deceits: How animals and plants exploit and mislead.

This book is an immensely informative and enjoyable exploration of the multiple roles deception plays in nature. Stevens sets out a detailed examination of a wide variety of instances of natural deception from well documented examples such as the evolution of camouflage through industrial melanism in the Peppered Moth (Biston betularia) to current research into the resemblance to falling leaves in the movement and colouration of Draco cornutus, a gliding lizard from Borneo. It is to Stevens’ credit that this book makes for entertaining and effortless reading while clearly citing all the relevant research within context and pointing to areas where knowledge is still lacking.

The language of deception is important. Stevens takes the time to explain some of the more commonly used terms associated with deception such as camouflage (blending in to the environment), mimicry (assuming the appearance – be that visual, chemical, behavioural or acoustic – of another organism) and masquerade (taking the form of an inedible object – as with stick insects). Mimicry and masquerade therefore lead to misidentification while camouflage reduces detectability or impairs recognition. Mimicry also comes in various guises some of which can be described as: aggressive, when predators mimic harmless species to enable prey capture; Batesian, when a palatable species mimics the characters of an unpalatable species, as seen in the chicks of an Amazonian bird Laniocera hypopyrra mimicking toxic caterpillars; and imperfect mimicry, as with hoverflies roughly resembling certain species of wasps and bees (for which there are a number of competing theories).

This, of course, only scratches the surface of a vast area of research that Stevens specialises in as head of the Sensory Ecology and Evolution group at the University of Exeter where he continues to research these themes. His enthusiasm for his topic is highly infectious; you find yourself transported from an explanation of background matching in cuttlefish, to an historical aside concerning the development of military camouflage, and on again to a description of his own field experiments in testing the efficacy of disruptive colouration.

“We must trust to nothing but facts: these are presented to us by nature and cannot deceive. We ought, in every instance, to submit our reasoning to the test of experiment, and never to search for truth but by the natural road of experiment and observation.” ~ 18th-century chemist Antoine Lavoisier

The book does rely heavily on zoological examples, and although Stevens doesn’t entirely neglect plants his observations do tend to mainly focus on carnivorous plants and orchids. But to be fair, Stevens does make the point that more research into botanical forms of deception is required and suggests that this should be undertaken with a view to specifically exploring the roles of chemical signalling and sensory exploitation. One of the examples cited in the book is the orchid Epipactis veratrifolia which attracts female hoverflies to lay eggs on the plant by releasing chemicals that mimic the alarm pheromones of aphids (the food source of hoverfly larvae). This may rather be a means by which the orchid exploits an inbuilt perceptual preference for chemicals associated with hoverfly larval food sources – either way the plant is deceiving the insect in order to ensure protection from aphid infestation.

A form of deception more commonly associated with orchids is that of exploiting male insects to pollinate plants by mimicking the female form through the shape and colouration of the flower. However, Stevens points out that this mimicry is sometimes (as in Cryptostylis orchids) not particularly convincing to human eyes, but is overwhelmingly so to the male wasp which tries to mate with the flower and thus collects the pollinium which will be deposited at the next Cryptostylis flower that he visits. With this example (as with the oil beetle, among others) the author cautions researchers of deception in nature to be aware of anthropocentric biases that may arise through our observations and study, and to (wherever possible) approach our subjects in the manner and with the senses of the deceived species.

I am utterly delighted and inspired by this book and am certain that I will return to it again and again as a point of reference. I have no hesitations in highly recommending it to researchers, field naturalists and those with a passing interest in natural history.

Postscript

At the time of writing, Phil Torres and Aaron Pomerantz have discovered and documented kleptoparasitism of ants in a species of butterfly (Adelotypa annulifera) in the Peruvian Amazon which they believe might mimic ants through their wing patterns. This seems to me an ideal opportunity for further research looking at visual and chemical mimicry given both the wing patterns and larval associations.

Getting down and dirty with the Earthworm Society of Britain

I attended the Earthworm Society of Britain‘s annual general meeting at Cannock Chase Forest where I got to meet fantastic amateur enthusiasts, very knowledgable naturalists with a general interest in worms, and some hardcore earthworm specialists. It was an immensely enjoyable couple of days of field recording in various habitats found here including broadleaved woodland, grassland and heath as well as microhabitats such as dead wood.

“It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organised creatures”. Charles Darwin

Since Darwin’s observations and experiments with earthworms was first published in 1881 under the title The Formation of Vegetable Mould, Through the Action of Worms, With Observations on Their Habits a new area of little-known research relating to these fascinating creatures was born. Despite this, we still find a lamentable lack of data regarding the distribution of earthworms throughout the UK and are continuing to research the ecosystem-wide implications of their below-ground activity.

In attending the society’s field day and AGM I was curious to find whether earthworms would pique my interest as a naturalist and scientist or whether I had developed a nostalgic yearning for simpler times. I have vivid memories of when, as a child, I would gingerly lift the edge of the damp burlap sack to scoop out trowel-fulls of fusty earth from half an oil drum in which my grandfather bred earthworms to bait his fishing hooks. I think the answer is that they are probably both true. This area is rich for contributions to research and recording while also being a great opportunity to get my hands stuck in some dirt and forget about my everyday worries. And when Amy Stewart so eloquently points out in response to the relevance of Darwin’s research and the significance of earthworms, that they’re “…only carrying out the natural order of things, folding the ruins of a farm, a city, or a society into the lower strata of the earth. When our civilizations end, and when we as individuals die, we don’t ascend, not physically. We descend. And the earth rises up to meet us”, how could I resist?

Day 1

Looking for earthworms is a messy affair and you have got to be prepared to get dirty. Armed with spades, sorting trays and all-weather gear we set out to see what the various sites had to offer.

ESB We started with the damp, waterlogged woodland near the classroom we had booked for the day and were immediately set upon by midges and mosquitoes. Ankle-deep in mud, and stippled with insect bites we dug 5 soil pits here with a reasonable haul of worms before making a break for an area of bracken further up the slope and farther away from the biting flies. We didn’t find any earthworms in the bracken pits, but were entertained by a greater spotted woodpecker feeding her voracious and loudly calling young in a nearby nesting hole before we again set off to a new site. A stop on the way to explore the banks of a stream and some adjacent dead wood in varying states of decay provided a few more worms for our count as well as other obligatory detritivores – millipedes, centipedes and woodlice.

It was in the pits dug from the grass verge alongside a footpath with flowering speedwell and buttercups where the highest number of earthworms were found, along with leatherjackets and other unidentified fly and beetle larvae. Our small party of slightly bedraggled and filthy earthworm explorers then headed back to the Forestry Commission classroom. Looking to all the world like a group of unsuccessful treasure hunters or end-of-shift gravediggers we traipsed back to the promise of piping hot tea and freshly made sandwiches while a retinue of dog walkers, mountain bikers and Segway riders passed us by. After lunch we could be found sitting in drifts of leaf litter in an old disused drainage ditch beneath a small stand of beech trees opposite the car park where we turned up a few more worms.

Then on to the AGM. First we were treated to a fascinating presentation on the worldwide diversity of earthworms (look out for the fried egg worm when in the Philippines) and an update on the ongoing search for the world’s longest earthworm (currently hotly contested between researchers in the Amazon and another in South Africa) by the society’s chair. Thereafter, the recording officer presented an assessment of the state of earthworm recording in the UK compared to other ‘more charismatic’ species such as butterflies – I think it’s fair to say that we have some way to go yet, but that significant progress has been made since the establishment of the society. New members were elected to the committee (I am delighted to have been accepted as the new treasurer) and all matters were concluded and followed by dinner and drinks in a local pub.

Day 2

The next morning started with a sighting of a pair of Little Ringed Plovers on a derelict brownfield site near the hotel where we were staying before we bundled into cars and headed back to Cannock Chase with the intention of doing some mustard sampling, digging soil pits in the heath and surveying areas that were being grazed by cattle. We set off on foot from the car park along the road until we reached a small wooded area with birch trees and much dead wood where we started collecting worms accompanied by the call of a cuckoo.

And then on to the next site where the shallow, stony and root-filled heathland pits that we eventually managed to dig were predictably uninhabited by earthworms; but we did manage to extract some from beneath some carpet tiles that had been scattered on a grassy area nearby using the diluted mustard concoction below (which I’ve been told is as indispensable as a spade to earthworm recorders).

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A little further down the path a rather large felled tree was rolled away to reveal more worms and a host of other creatures including a palmate newt, a toad, an unidentified moth larva, pill millipedes, centipedes and carabid beetles. We were also treated to a view of a tree pipit calling from the top of an oak and the slightly stumbling flight of a scorpion fly. We then made our way on to the grazed area where we wanted to do our final sampling for the day. Or we would have, but as we walked past the cinnabar moths and the many humped yellow meadow ant nests we realised that we may have misjudged the distance somewhat, so picked up the pace but didn’t get there with enough time to do any sampling. As a consolation we did spy a green tiger beetle scuttle across the chalk path as we now hastened back to the car park for a final catch up before scrubbing our hands clean and going our separate ways.

More information

You may have noticed that for a blog post on earthworms, this has been fairly light on any detailed earthworm records. This is because we don’t yet have our full set of records from those who attended the field days, and for my part as I am still a complete novice I am still working my way through the ID process. For ID resources, there is an excellent key by Emma Sherlock and an online multi-access key developed by Richard Burkmar, both of which I highly recommend.

For a bit more information about earthworms and some of the work of the Earthworm Society watch this short youtube video produced by Eco Sapien and the FSC explaining why earthworms are important.

To get involved you can either contact the Earthworm Society directly or if you first want to try your hand at surveying earthworms you can take part in the citizen science project Earthworm Watch.