A University of Sussex PhD thesis Available online via Sussex Research Online: http://sro.sussex.ac.uk/ This thesis is protected by copyright which belongs to the author. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the Author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the Author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given Please visit Sussex Research Online for more information and further details Novel aspects of nest defence in stingless bees Kyle Shackleton Submitted for the degree of Doctor of Philosophy Submission date: May 2018 University of Sussex Declaration I declare that the work carried out in this thesis is entirely done by me, and that any help provided by other individuals with data collection and analysis is fully acknowledged. I certify that this thesis has not and will not be submitted - in whole or part, to another university for the award of any other degree. Signature: Kyle Shackleton i University of Sussex Kyle Shackleton PhD Environmental Science Novel aspects of nest defence in stingless bees Summary Defence against predators is fundamental to increasing an organism’s fitness. My thesis explores this central theme in behavioural ecology using stingless bees as study organisms. The thesis contains a general introduction (Chapter 1), three data chapters (2-4) and a final discussion (5). Chapter 2 is a comparative study of aggression in nest defence among stingless bee species, and describes a new form of nest defence, suicidal biting, which is most prevalent in the genus Trigona. Chapter 3 describes a remarkable behaviour in Partamona helleri, which crashes head- first when entering its nest. An experiment suggests that this behaviour helps to avoid predation at the nest entrance. Chapter 4 studies nest defence in the hovering guards of Tetragonisca angustula, and demonstrates that through coordinated vigilance, a group level behaviour rarely observed in animals, the ability of the group to detect predators is enhanced. ii Publications arising from this thesis Shackleton, K., Toufailia, H.A., Balfour, N.J., Nascimento, F.S., Alves, D.A., Ratnieks, F.L.W. (2015) Appetite for self-destruction: suicidal biting as a nest defense strategy in Trigona stingless bees. Behavioral Ecology and Sociobiology 69, 273–281. (Chapter 2). Shackleton, K., Alves, D.A., Ratnieks, F.L.W. Spatial organisation enhances collective vigilance in the hovering guards of Tetragonisca angustula stingless bees. Behavioral Ecology (accepted). (Chapter 4). Other papers published during my PhD Shackleton, K., Ratnieks, F.L.W. (2016) Garden varieties: How attractive are recommended garden plants to butterflies? Journal of Insect Conservation 20, 141–148. Ratnieks, F.L.W., Shackleton, K. (2015) Does the waggle dance help honey bees to forage at greater distances than expected for their body size? Frontiers in Ecology and Evolution 3, 31. Shackleton, K., Balfour, N.J., Al Toufailia, H., Gaioski, R., de Matos Barbosa, M., Silva C.A. de S., Bento, J.M.S., Alves, D.A., Ratnieks, F.L.W. (2016) Quality versus quantity: Foraging decisions in the honeybee (Apis mellifera scutellata) feeding on wildflower nectar and fruit juice. Ecology and Evolution 6, 7156–7165. To be submitted Shackleton, K., Balfour, N.J., Al Toufailia, H., Alves, D.A., Ratnieks, F.L.W. Unique nest entrance structure of Partamona helleri stingless bees leads to remarkable ‘crash landing’ predator avoidance behaviour. (Chapter 3). iii Acknowledgements I would first like to thank my supervisor Prof Francis Ratnieks for employing me in the first place, although he did blurt out soon after that I had not been his first choice candidate. Francis was a source of ideas throughout the PhD and particularly early on, he gave me the guidance and encouragement to succeed. Thanks also to my second supervisor Prof Dave Goulson who was helpful in providing a different perspective on manuscripts. The PhD would not have been possible without my funders, the National Environment Research Council (NERC) and the University of Sussex School of Life Sciences. I also received smaller grants from the Royal Entomological Society and Santander Bank which allowed me to travel to Brazil for fieldwork. Past and present members of the Laboratory of Apiculture and Social Insects (LASI) were extremely welcoming, provided technical support, insightful discussions and great company are Margaret Couvillon, Roger Schürch, Hasan Al Toufailia, Nicholas Balfour, Mihail Garbuzov, Gianluigi Bigio, Luciano Scandian, Karin Alton, Christoph Grüter, Francesca Segers, Tom Butterfield and Alan Gallagher. Other members of the School of Life Sciences who facilitated research and provided helpful advice are Martyn Stenning, Rob Fowler and Victoria Norman. Many others helped with the sometimes monotonous task of data collection, and most did so as volunteers without pay. Felix Shrell was a tireless worker during my first year of fieldwork, Martin Stock, Clare Maurin and Ellie Blows all helped with dance decoding, while Roberto Gaioski Jr, Marcela Barbosa and Carina Silva were all willing and able helpers in Brazil. The annual trips to Brazil would not have been possible without those who helped to acquire funding, opened up their labs to us and often drove us to delicious restaurants. I would like to thank Denise Alves, Jose Mauricio Bento, Luis Marchini, Fabio Nascimento and Sidnei Matteus in this regard. iv I would like to thank the anonymous reviewers who have commented my manuscripts over the past four years, who provided constructive criticism and helped to improve the papers. Last I would like to thank my parents, Margaret and Michael Shackleton, for cultivating my interest in the natural world from an early age. v Contents Declaration ......................................................................................................................... i Summary ........................................................................................................................... ii Publications arising from this thesis ................................................................................ iii Acknowledgements .......................................................................................................... iv Chapter 1 – General introduction ...................................................................................... 1 1.1 General background to predator defence ................................................................ 1 1.2 Study species – the stingless bees ........................................................................... 2 1.3 Who are the enemies of stingless bees? .................................................................. 6 1.4 Threat detection ..................................................................................................... 10 1.5 Defenders of the fortress ....................................................................................... 14 1.6. Natural history aspects of nest defence ................................................................ 17 1.7 Self-sacrificial defence .......................................................................................... 19 1.8 Individual level defence ........................................................................................ 23 Chapter 2 – Appetite for self-destruction: suicidal biting as a nest defence strategy in Trigona stingless bees ..................................................................................................... 25 2.1 Abstract ................................................................................................................. 25 2.2 Introduction ........................................................................................................... 25 2.3 Methods ................................................................................................................. 27 2.4 Results ................................................................................................................... 31 2.5 Discussion ............................................................................................................. 35 Chapter 3 – Unique nest entrance structure of Partamona helleri stingless bees leads to remarkable ‘crash landing’ predator avoidance behaviour ............................................. 41 3.1 Abstract ................................................................................................................. 41 3.2 Introduction ........................................................................................................... 41 3.3 Methods ................................................................................................................. 45 3.4 Results ................................................................................................................... 47 3.5 Discussion ............................................................................................................. 52 vi Chapter 4 – Spatial organisation enhances collective vigilance in the hovering guards of Tetragonisca angustula stingless bees ............................................................................ 59 4.1 Abstract ................................................................................................................