AN ECOLOGICAL STUDY OF SOME OF THE CHIRONOMIDAE INHABITING A SERIES OF SALINE LAKES IN CENTRAL BRITISH COLUMBIA WITH SPECIAL REFERENCE TO CHIRONOMUS TENTANS FABRICIUS by Robert Alexander Cannings BSc. Hons., University of British Columbia, 1970 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in the Department of Zoology We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA May, 1973 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia Vancouver 8, Canada Date ii ABSTRACT This thesis is concerned with a study of the Chironomidae occuring in a saline lake series in central British Columbia. It describes the ecological distribution of species, their abundance, phenology and interaction, with particular attention being paid to Chironomus tentans. Emphasis is placed on the species of Chironomus that coexist in these lakes and a further analysis is made of the chromo• some inversion frequencies in C. tentans. Of the thirty-four species represented by identifiable adults in the study, eleven species have not been previously reported in British Columbia, five are new records for Canada and seven species are new to science. The chironomid fauna of the lake series is divided into dominant associations whose existence seems to depend on salinity and productivity levels. A Cricotopus albanus - Procladius bellus - Ablabesmyia peleensis association pre• vails in the lowest salinities (40 to 80 jumho/cm conductivity) while in conductivities between 400 and 2800 jumho/cm a Glyptotendipes barbipes - Einfeldia pagana association domin• ates. In the most saline lakes (conductivity 4100 to 12000 jumho/cm) a Calopsectra gracilenta - Cryptotendipes ariel association is characteristic. Analysis of physical and chemical factors influencing the life cycle of C. tentans indicates that conditions associated with high levels of organic carbon promote large numbers of larvae and greater emergence success. The results suggest that competition between C. tentans and other Chironomus species is reduced through spatial separation due to different preferences for salinity or related factors. Furthermore, temporal separation among these and other abundant species such as G. barbipes and E. pagana occurs as a result of staggered generation times. The inversion frequency in chromosome 1 of C. tentans is negatively correlated with organic carbon levels and posi• tively correlated with dissolved oxygen and the abundance of Glyptotendipes barbipes. Since the inversion frequency is lowest in habitats where competing species are few and where C. tentans is most successful, it is suggested that the inver• sion governs a mechanism reducing competition. A major contribution of this work is the revision of the distribution of many of the chironomid species under considera• tion. In the past, little research has been done on popula• tions of chironomids in a saline lake series. The present study, in attempting to fill this gap in entomological research, shows that a species' life history and population structure can vary radically in closely associated lakes of differing chemical and biological constitution. IV TABLE OF CONTENTS Page Title Page i Abstract ii Table of Contents iv List of Tables vi List of Figures viii List of Plates xi Acknowledgements xii I INTRODUCTION 1 II THE LAKE ENVIRONMENTS 4 A. THE STUDY AREA 4 B. THE PHYSICAL AND CHEMICAL PROPERTIES OF THE LAKES 8 III SPECIES DIVERSITY AND THE CHIRONOMID COMPLEX IN THE LAKE SERIES 17 A. MATERIALS AND METHODS 17 1. Temperature Records 17 2. Biological Sampling Methods 17 a) Larval Sampling 17 b) Adult Sampling 19 3. Rearing of Specimens 23 4. Preparation and Identification of Specimens 24 5. Analysis of the Data 24 6. Storage of the Data for Further Study 24 B. RESULTS 26 1. Water Temperatures in the Lake Series 26 2. Chemical Data 30 3 The Occurrence of Species in the Lakes 30 4. Species Considered in Detail 33 5. The Chironomid Complex and the Lake Series 85 a) The Cricotopus albanus - Procladius bellus - Ablabesmyia peleensis association 85 b) The Glyptotendipes barbipes - Einfeldia pagana association 86 c) The Calopsectra gracilenta - Cryptotendipes ariel association 88 C. DISCUSSION 1. The Chironomidae and the Lake Series 91 2. Chironomus tentans and the Lake Series 102 a) Physical and Chemical Influences 102 b) Biotic Interactions 106 IV CHIRONOMUS TENTANS AND SOME BIOTIC FACTORS AFFECTING CHROMOSOME INVERSION 113 A. MATERIALS AND METHODS 113 B. RESULTS 115 C. DISCUSSION 121 r V CONCLUSION 125 Literature Cited 129 Appendix 140 vi LIST OF TABLES Page TABLE I Physical and chemical properties of the lakes. 10 TABLE II Average water temperature in the lake series. 27 TABLE III The distribution of chironomids in the one meter depth zone in the lakes. 31 TABLE IV The distribution of larvae unidentified to species. 32 TABLE V Summary of correlation coefficients describing the relationship between environmental factors and the amount of emergence of certain species. 76 TABLE VI The correlation between emergence histogram dispersion and environmental factors. 77 TABLE VII Summary of correlation coefficients describing relationships between environmental factors and species abundance. 78 TABLE VIII Summary of correlation coefficients describing the relationship between environmental factors and species per cent composition. 79 TABLE IX Summary of correlation coefficients describing the relationship between environmental factors and the amount of emergence. 80 TABLE X Summary of the correlation coefficients describing the relationship between environmental factors and the number of emergence peaks for various species. 81 TABLE XI Summary of correlation coefficients describing the relationship between environmental factors and the times of major emergence in several species. 82 VIX TABLE XII Summary of correlation coefficients describing the relationship between larval abundance, numbers of emerging adults, number of emergence peaks and emergence time. 83 TABLE XIII The developmental rates of C. tentans in various lakes. 84 TABLE XIV The percentage composition of species in the lakes based on the total adult emergence, May - August, 1970. 90 TABLE XV Inversion frequencies in chromosome 1 of C. tentans. 116 TABLE XVI Summary of correlation coefficients describing the relationship between the frequency of 1 Rad and some environmental factors. 117 TABLE XVII Summary of correlation coefficients describing the relationship between the frequency of 1 Rad and the abundance of some chironomids. 118 TABLE XVIII Summary of correlation coefficients describing the relationship between the frequency of 1 Rad and the per cent composition of some chironomids, 119 TABLE XIX Summary of correlation coefficients describing the relationship between the frequency of 1 Rad and some emergence variables. 120 viii LIST OF FIGURES Page FIGURE 1 The study area; Springhouse region. 5 FIGURE 2 The study area; water bodies in the Chilcotin region. 6 FIGURE 3 Details of the emergence trap. 22 FIGURE 4 Daily temperature range in some of the lakes where Chironomus tentans is abundant. 28 FIGURE 5 Cumulative day degrees measured at the mud surface at a depth of 1 meter in some of the lakes where Chironomus tentans is abundant. 29 FIGURE 6 The emergence of adults of Procladius bellus (Loew) and Procladius freemani Sublette from the one meter depth zone of several lakes. 35 FIGURE 7 The emergence of adults of Procladius dentus Roback from the one meter depth zone of several lakes. 37 FIGURE 8 The emergence of adults of Procladius clavus Roback and Ablabesmyia peleensis (Whalley) from the one meter depth zone of several lakes. 40 FIGURE 9 The emergence of adults of Cricotopus flavibasis Malloch and Cricotopus albanus Curran from the one meter depth zone of several lakes. 43 FIGURE 10 The emergence of adults of Psectrocladius barbimanus (Edwards) from the one meter depth zone of several lakes. 45 FIGURE 11 The emergence of adults of Crypto- tendipes ariel (Sublette) and Calopsectra gracilenta (Holmgren) from the one meter depth zone of several lakes. 47 ix FIGURE 12 Larval abundance and adult emergence of Perotanypus alaskensis (Malloch) in L. Lye, Boitano L. and L. Jackson. 50 FIGURE 13 Larval abundance and adult emergence of Derotanypus alaskensis (Malloch) in Rock L., Sorenson L. and East L. 51 FIGURE 14 Larval abundance and adult emergence of Einfeldia pagana Meigen in L. Jackson, Rock L. and Westwick L. 55 FIGURE 15 Larval abundance and adult emergence of Einfeldia pagana Meigen in Near Opposite Crescent, Barkley L. and East L. 56 FIGURE 16 Larval abundance and adult emergence of Glyptotendipes barbipes (Staeger) in L. Jackson, Westwick L. and Sorenson L. 58 FIGURE 17 Larval abundance and adult emergence of Glyptotendipes barbipes (Staeger) in Rock L., Barkley L. and East L. 59 FIGURE 18 Larval abundance and adult emergence of Chironomus anthracinus Zetterstedt in Boitano L., L. Jackson and Rock L. 62 FIGURE 19 Larval abundance and adult emergence of Chironomus anthracinus Zetterstedt in Sorenson L., Barkley L. and East L. 63 FIGURE 20 Larval abundance and adult emergence of Chironomus n.sp. in Barnes L., Boitano L. and L. Jackson 66 FIGURE 21 Larval abundance and adult emergence of Chironomus n.sp. in Rock L. and Sorenson L. 67 FIGURE 22 Larval abundance and adult emergence of Chironomus n.sp. in Barkley L. and East L. 68 FIGURE 23 Larval abundance and adult emergence of Chironomus tentans Fabricius in L. Jackson, Westwick L. and Sorenson L. 74 FIGURE 24 Larval abundance and adult emergence of Chironomus tentans Fabricius in Rock L., Barkley L.