HETEROSPECIFIC SOCIAL INTERACTIONS OF THE INVASIVE GUPPY (POECILIA RETICULATA): A POTENTIAL TRAIT TO ENHANCE INVASIVE SUCCESS Morelia Camacho-Cervantes A Thesis Submitted for the Degree of PhD at the University of St Andrews 2014 Full metadata for this item is available in Research@StAndrews:FullText at: http://research-repository.st-andrews.ac.uk/ Please use this identifier to cite or link to this item: http://hdl.handle.net/10023/6561 This item is protected by original copyright Heterospecific social interactions of the invasive guppy (Poecilia reticulata): a potential trait to enhance invasive success A thesis submitted for the degree of Ph.D. at the University of St Andrews Morelia Camacho-Cervantes September 2014 Declaration I, Morelia Camacho-Cervantes, hereby certify that this thesis, which is approximately 30,000 words in length, has been written by me, that it is the record of work carried out by me and that it has not been submitted in any previous application for a higher degree. I was admitted as a research student in September 2011 and as a candidate for the degree of Ph.D. in September 2012; the higher study for which this is a record was carried out in the University of St Andrews between 2011 and 2014. Date Dec 11th 2014 Signature of candidate I hereby certify that the candidate has fulfilled the conditions of the Resolution and Regulations appropriate for the degree of Ph.D. in the University of St Andrews and that the candidate is qualified to submit this thesis in application for that degree. Date Dec 11th 2014 Signature of supervisor In submitting this thesis to the University of St Andrews we understand that we are giving permission for it to be made available for use in accordance with the regulations of the University Library for the time being in force, subject to any copyright vested in the work not being affected thereby. We also understand that the title and the abstract will be published, and that a copy of the work may be made and supplied to any bona fide library or research worker, that my thesis will be electronically accessible for personal or research use unless exempt by award of an embargo as requested below, and that the library has the right to migrate my thesis into new electronic forms as required to ensure continued access to the thesis. We have obtained any third-party copyright permissions that may be required in order to allow such access and migration, or have requested the appropriate embargo below. The following is an agreed request by candidate and supervisor regarding the electronic publication of this thesis: Access to printed copy and electronic publication of thesis through the University of St Andrews. Date Dec 11th 2014 Signature of candidate Signature of supervisor ! Abstract From all the species that arrive to a novel environment, very few manage to form a viable population. The guppy, a very successful invader, is a highly social species that performs some of its vital tasks (e.g., foraging, avoiding predators) in groups. This thesis aimed to quantify heterospecific association benefits that enhance invasion success. Interactions between invaders and natives could be one of the environmental characteristics of a place that increase its risk of invasion. I evaluated the tendency of an invasive species to associate with native individuals with similar ecological requirements. I tested the hypothesis that invaders gain exploring, acquisition of information and foraging benefits when socializing with natives. In these experiments I used the guppy as the invasive model species and endangered native Mexican topminnows (Poeciliopsis infans, Skiffia bilineata, Ameca splendens, Zoogoneticus tequila, Xenotoca eiseni and Girardinichthys viviparous). I found that guppies shoal with other species in Trinidad (Poecilia picta and Poecilia sphenops), where they are native (Chapter 2) and that this trait remains when they are invasive (Chapter 3). Guppies are equally willing to explore novel environments when accompanied by heterospecifics or conspecifics. Guppies are more willing to explore complex environments than simple ones. Moreover, when exploring simple environments they have a higher association tendency, regardless of the partner’ species (Chapter 4), which could lead them to acquire the benefits of grouping behaviour and avoid Allee effects - the disadvantages of being part of a small group. In the contexts in which they were tested guppies gained as much information by associating with heterospecifics as with conspecifics (Chapter 5). Finally, I found that when shoaling in bigger shoals guppies are able to locate food faster and spent more time foraging. The benefits of increased shoal size were maintained when the additional guppies were replaced with heterospecifics. However, they derive more benefits from the species they are more willing to associate with (Chapter 6). These results uncover a mechanism enabling founding individuals to survive during the most vulnerable phase of an invasion and help explain why guppies have established viable populations in many parts of Mexico as well as in every continent except Antarctica. Acknowledgements I would like to thank Prof. Anne Magurran for her excellent supervision throughout my time at the University of St Andrews. I always came out of her office with better perspectives and more interesting ideas. I could not have completed this thesis without the support of Dr. Alfredo Ojanguren, who acted as a co-supervisor and had his door open for me and my questions at all times. Thanks to my tutor Prof. Thomas Meagher and my internal examiners Dr. Carl Smith and Dr. Jeff Graves for their helpful comments and discussions. To Al Reeve and Dr. Miguel Barbosa thanks for the endless discussions, the fieldwork and lab support. Thanks to Dr. Hideyasu Shimadzu, Dr. María Dornelas, Faye Moyes and the rest of the Fish Lunch discussion group members for sharing ideas and helping me better understand my data. And to my friends in México and St Andrews who helped me proofread chapters and articles, listened to my talk rehearsals and discussed with me scientific ideas or simply bureaucracy burdens. The work in México was possible thanks to the support of Dr. Constantino Macías at UNAM and Dr Omar Domínguez at UMSNH. Thanks to both and to the lab members of their groups, Laboratorio de Biología Acuática and Laboratorio de Conducta Animal respectively, especially to Edgar Luna and Diego Chechenquillo. Work in Trinidad was possible thanks to the support of Dr. Amy Deacon, Kharran Deonarienesingh and Dr. Indar Ramnarinne. In St Andrews, Dr. Andrew Whiston, Steve, Cara and the St Andrews Aquarium provided me with a population of goodeidae fish, thanks to them as well. Hugo Camacho and Cristian Cortés, thanks for driving me around so much to place data loggers and collect fish. María and Sofía Zirión, Hernando Rodríguez and Adrián Ortega, thanks for help me collect fish. Sorry about the sunken phone and Petrush’s injuries. Ian MacGregor-Fors, this whole doing-a-PhD idea started sitting next to you. Thanks for your help and support though the entire process. A very special thanks to my parents for their support in all the possible ways; from listening to everything I had to say and complaint about life abroad, science stuff or just anything, to financially support my trips to México and some of the fieldwork there. (Un agradecimento muy especial a mis padres por su apoyo en todas las formas posibles; desde escuchar todo lo que tuve que decir y quejarme de la vida fuera de México, ciencia o cualquier cosa, hasta su apoyo económico para pagar mis viajes a México y parte del trabajo de campo ahí. Gracias Oracio y Lupita por ayudarme incondicionalmente.) Finally, I want to thank my funding bodies CONACyT, COECyT and the Research Committee of the School of Biology. Para Duk y Abeja Heterospecific social interactions of the invasive guppy (Poecilia reticulata): a potential trait to enhance invasive success Contents 1. General Introduction 10 1.1 invasion process 12 1.2 Freshwater systems under threat 18 1.3 Benefits of living in groups during invasion 19 1.3.1 Shoaling behaviour 22 1.4 Allee effects 23 1.5 Heterospecific social interactions 26 1.6 The guppy, an ideal study species for invasion 26 1.7 Vulnerable Mexican fish communities 30 1.8 Aims 36 2. Association tendency and preference for 38 heterospecifics in an invasive species 2.1 Abstract 39 2.2 Introduction 40 2.2.1 Sociability 40 2.2.2 Heterospecific interactions 40 2.2.3 The social guppy 41 2.2.4 Aims 42 2.3 Methods 43 2.3.1 Data analysis 51 2.4 Results 52 2.4.1 Shoaling Tendency 52 2.4.2 Shoaling Preference 53 2.5. Discussion 54 3. High sociability as a key trait for invasion success: 57 a case study in the Mexican Central Plateau 3.1 Abstract 58 3.2 Introduction 59 3.2.1 Facilitation between species 59 3.2.2 Native species under risk 60 3.2.3 Aims 61 3.3 Methods 62 3.3.1 Data analysis 66 3.4 Results 66 3.5 Discussion 67 4. Boldness and exploratory behaviour with 70 heterospecifics in complex and simple habitats 4.1 Abstract 71 4.2 Introduction 72 4.2.1 Refuge use and exploring behaviour 72 4.2.2 Boldness 73 4.2.3 Aims 73 4.3 Methods 74 4.3.1 Data analysis 76 4.4 Results 77 4.4.1 Boldness 77 4.4.2 Exploring behaviour 78 4.5 Discussion 79 5. Transmission of information between native and 82 invasive fish species 5.1 Abstract 83 5.2 Introduction 84 5.2.1 Foraging in groups 84 5.2.2 Social learning 84 5.2.3 Aims 85 5.3 Methods 86 5.3.1 Data analysis 89 5.4 Results 90 5.5 Discussion 92 6.