Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1973 The ffecE t of Thyroxine and Thiourea on Territorial Behavior in Cichlid Fish. Peter Harry Spiliotis Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Spiliotis, Peter Harry, "The Effect of Thyroxine and Thiourea on Territorial Behavior in Cichlid Fish." (1973). LSU Historical Dissertations and Theses. 2573. https://digitalcommons.lsu.edu/gradschool_disstheses/2573 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS This material was produced from a microfilm copy of the original document. 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Michigan 4B106 74-18,369 SPILIOTIS, Peter ferry, 1946- THE EFFECT OF THYROXINE AND THIOUREA ON TERRITORIAL BEHAVIOR IN CICHLID FISH. The Louisiana State University and Agricultural and Mechanical College, Ph.D., 1973 Psychology, general University Microfilms, A XEROX Company, Ann Arbor, Michigan THIS DISSERTATION HAS BEEN MICROFILMED EXACTLY AS RECEIVED. THE EFFECT OF THYROXINE AND THIOUREA ON TERRITORIAL BEHAVIOR IN CICHLID FISH A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Psychology by Peter Harry Spiliotis B .A ., The University of North Carolina, 1969 M .A ., Louisiana State University, 1971 December, 1973 ACKNOWLEDGMENT The author would like to thank his major professor Dr, Donald R. Hoffeld for his guidance and assistance during this project. The author would also like to express gratitude to members of his committee, Dr. Albert H. Meir, Dr, Billy M, Seay, Dr, Arthur J. Riopelle, and Dr. Nathan W. Gottfried. Special thanks is extended to Dr. Laurence Siegel, Chairman of the Department of Psychology and Dr. Irwin A. Berg, Dean of the School of Arts and Sciences who made available funds in support of this dissertation. I am Indeed grateful to the typist, Mrs. Mary Mevers. ii TABLE OF CONTENTS Page TITLE P A G E ....................................................... i ACKNOWLEDGMENT.................................................. ii LIST OF T A B L E S .................................................. iv ABSTRACT ......................................................... v INTRODUCTION ..................................................... I Functional Considerations of Thyroid Hormones ............... 3 Territorial Behavior and Its Components . ............... 8 P u r p o s e ....................................................... 13 METHOD ........................................................... 15 Subjects....................................................... 15 A ppar a t u s ..................................................... 15 Procedure..................................... 16 Statistical Analysis and Informal Data....................... 19 RESULTS........................................................... 21 Reliability........................... 21 Quantitative Behavior Measures................................ 21 Qualitative Observational Data................................ 26 S u m m a r y ................................................ 30 DISCUSSION....................................................... 33 Hormones and Territoriality .................................. 33 Activity and Locomotor Levels ................................ 37 Pigmentation and Coloration Displays......................... 37 Drug Dosage ................................................... 39 Rhythmicity ......... ........ ........... 40 REFERENCES....................................................... 41 APPENDIX ......................................................... 51 VITA ............................................................. 55 iii LIST OF TABLES Table Page 1. Mean Frequency of Behavior Categories for each Defended Territory in Group I ......................... 22 2. Mean Frequency of Behavior Categories for each Defended Territory in Group II......................... 23 3. Mean Frequency of Behavior Categories for each Defended Territory in Group III ...................... 24 iv ABSTRACT Two species of mature cichlids, Cichlasoma meeki and Cichlasoma biocellatum, exhibited behavioral changes in critical stimuli involved in defense of a territory after prolonged thyroxine treatment. Fish exhibited increased locomotor activity, changes in integument pigmenta­ tion which corresponded to adopted functional behaviors, and spent con­ siderably more time on the surface of aquaria. Only C. meeki showed flutter behavior. Dominant territorial fish tended to increase the area of their territory and their dominance over nonterritorial members. In C. meeki prolonged thyroxine resulted in significant increases in two behavior categories from baseline--territorial mouth fighting (Tm, p ^.005) and nipping of the subtrate outside the territorial pit (N, p<.025). Similar increases in the frequency of nipping (p <^.025) occurred in C. biocellatum. These changes suggest that thyroxine may have a role in agonistic behavior during defense of a territory and also effects critical stimuli involved in territorial behavior. The standard aquarium setting and social category system place limitations on the extent that intensification of territorial behavior can be evaluated. Thiourea treated C. meeki abandoned previously defended territories, developed darker integument pigmentation, grouped together and schooled stationary at the bottom of each aquaria. The diminution in activity consisted of uncoordinated jerky movements, persistent beating of pectoral fins, and periodic bouts of agonistic behavior. Within 2 weeks of the thiourea treatment, all behavior categories significantly decreased (p -^.025). Thiourea treatment decreased the number of critical sign stimuli necessary for the execution of territorial behavior. Thiourea dosage level was critical and JJ. meeki are suscep­ tible to prolonged thiourea treatment. vi INTRODUCTION In vertebrate evolution, the forebrain haa attained an increas­ ing dominate control over certain behavior responses, with the result that they tend to escape hormonal control. In lower vertebrates, the influence of the forebrain may be less marked, and behavior sequences may be increasingly controlled by hormones (Beach, 1947, 1948). According to Beach, hormones act as chemical sensitizers which alter the responsiveness of the CNS to stimuli from the environment. How­ ever, there is little evidence for the exact functional role of the fish thyroid (Matty, I960) and the physiological effects and peripheral target of the fish thyroid hormones have been difficult to elucidate definitively (Berg, Gorbman, & Kobayaski, 1959; Gorbman, 1969). Fish are low in the vertebrate series and therefore may provide insight into the ways in which hormones have gained control over behavior in the course of vertebrate evolution. Moreover, fish possess a repertoire of behaviors which are relatively simple and much more rigid and stereotyped than those of higher vertebrates. In conjunction, territorial behavior exemplifies some adaptive features of fish. Territorial behavior in fish serves to: (1) regulate the population;* (2) provide food reserve for adults and young; (3) increase geograph­ ical range of the species; (4) provide undisturbed