Cold tolerance in Sonoran Desert Drosophilaspecies Item Type text; Thesis-Reproduction (electronic) Authors Cleaves, Lawrence Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 03/10/2021 09:26:39 Link to Item http://hdl.handle.net/10150/291510 INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may t)e from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. 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Ann Art)or, Ml 48106-1346 USA 800-521-0600 COLD TOLERANCE IN SONORAN DESERT DROSOPHILA SPECIES by Lawrence Scott Cleaves Copyright © Lawrence Scott Cleaves 2002 A Thesis Submitted to the Faculty of the DEPARTMENT OF BIOCHEMISTRY AND MOLECULAR BIOPHYSICS In Partial Fulflllnient of the Requirements For the Degree of MASTER OF SCIENCE WITH A MAJOR IN GENERAL BIOLOGY In the Graduate College THE UNIVERSITY OF ARLZONA 2002 UMI Number; 1409486 Copyright 2002 by Cleaves, Lawrence Scott All rights reserved. ® UMI UMI Microform 1409486 Copyright 2002 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Infomiation and Leaming Company 300 North Zeeb Road P.O. 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SIGNED: APPROVAL BY THESIS DIRECTOR This thesis has been approved on the date shown below: 3 TABLE OF CONTENTS ABSTRACT 6 INTRODUCTION AND HISTORICAL PERSPECTIVE 7 SPECIES UTILIZED IN THIS STUDY 13 MATERIALS AND METHODS 20 RESULTS 26 DISCUSSION 49 ACKNOWLEDGMENT 60 REFERENCES 61 4 LIST OF TABLES AND ILLUSTRATIONS TABLE 1, Drosophila Species Used in This Study 18 TABLE 2, Taxonomy of Drosophila Species Used in This Study 21 TABLE 3, Cold Shock Response in Drosophila Species 27 TABLE 4, Rapid Cold Hardening Response in Drosophila Species 35 TABLE 5, Prolonged Exposure at 0°C Response in Drosophila Species 39 FIGURE 1, Representative Phylogeny of Drosophila 19 FIGURE 2, Cold Baths Used in Experiments 22 FIG. 2a: Ice Bath with Circulator FIG. 2b: Sub-zero Water/Anti-freeze Bath FIGURES 3-9, Cold Shock graphs FIG 3: D. pseudoobscura 28 FIG. 4: D. melanogaster 29 FIG. 5: D. hydeii 30 FIG. 6: D. mettleri 31 FIG. 7; D. mojavensis 32 FIG. 8: D. niff'ospiracula 33 FIG. 9: D. paulistorum 34 FIGURES 10-11, Rapid Cold Hardening graphs FIG. 10; Males for five species 37 FIG. 11: Females for five species 38 5 LIST OF ILLUSTRATIONS - continued FIGURES 12-17, Prolonged Exposure at 0°C graphs FIG. 12: D. pseudoobscura 40 FIG. 13: D. melanogaster 41 FIG. 14: D. hydei 42 FIG. 15: D. metlleri 43 FIG. 16: D. mojavensis 44 FIG. 17: D. paulistorum 45 FIGURES 18-19, Prolonged Exposure at 0°C Comparison graphs FIG. 18: Males for six species 46 FIG. 19: Females for six species 47 6 ABSTRACT I examined resistance to cold temperature in seven Drosophila species from different habitats to determine the lower limits of cold tolerance. Three separate tests were administered to measure the; 1) response to a cold-shock exposure; 2) extent to which a short-term survival strategy, rapid cold hardening, was utilized by each species; and 3) degree to which each species would respond to a prolonged exposure at 0°C. As expected, the temperate-montane species, D. pseudoobscura, was the most cold-tolerant, whereas the least cold-tolerant was the tropical species, D. paulistorum. The two cosmopolitan species, D. hydei and D. melanogaster, and the three Sonoran Desert endemic species, D. mojavensis, D. nigrospiracula, and D. mettleri, demonstrated intermediate levels of cold-tolerance. Of the five species tested for rapid cold hardening, all exhibited the response, including the tropical representative. The results for the 0°C test paralleled the results of the cold shock test. The desert species tested proved surprisingly cold-tolerant, especially D. mojavensis. 7 INTRODUCTION AND HISTORICAL PERSPECTIVE Introduction Temperature is the most important abiotic factor affecting the survival and distribution of insects world-wide (Andrewartha and Birch 1954; Cohet et. al 1980; Morin et al. 1997), and a great deal of work has been focused on the topic, particularly in the last 50 years. Some of the fundamental questions in thermal biology include: How do insects adapt to and survive the stresses of temperature extremes? What role has temperature played in the ecology and evolution of species? What are the biochemical and physiological mechanisms insects use to tolerate high and low temperatures? What impact does temperature have on insect development, reproductive capacity, and behavior? This paper addresses the first two questions above in relation to cold tolerance in various Drosophila species. Although significandy more research has focused on the effects of high temperature on insects (Levins 1969; Denlinger et al. 1991; Heinrich 1993; Stratman and Markow 1998; Feder and Hoffman 1999), the last few decades have produced numerous investigations concerning the effects of cold temperature (Parsons 1977; Lee 1989; Lee and Denlinger 1991; Chen and Walker 1994; Gibert et al. 2001). Recent studies on Drosophila have attempted to identity cold tolerance parameters for a number of species firom a variety of habitats (Cohet et al. 1980; Stanley et al. 1980; Yamamoto and Ohba 1984a, 1984b; Kimura 1988; Hoffman and Watson 1993; Gibert and Huey 2001; Gibert 8 et al. 2001). One group which has not received much investigative attention for cold tolerance, however, is the desert species, which may experience severe frosts during winter months as well as rapid changes in diurnal temperature (Lowe et al. 1967; Heed 1982). The primary purpose of this study is to compare levels of cold tolerance in three species of desert Drosophila with four other species from the same genus, including one temperate, two cosmopolitan, and one tropical representative. Historical Perspective Serious investigations in cryobiology began in the mid-19"* century when research focused on the economic importance of producing frost-hardy plant crops (Payne 1926). Between the latter part of the 19''' and the middle of the 20"* century, insects became popular as subjects of cryobiology research not only because of their obvious impact on plants, but also because of a growing interest in determining the effect of low temperature on insect ecology, geographic distribution, and behavior (Salt 1936, 1950,1956; Novitski and Rush 1949; Knipling and Sullivan 1957). Since the 1950's, investigations in cryobiology have included a wide variety of other poikilothermic organisms (Block 1982; Zachariassen 1982; Storey and Storey 1988; Loomis 1991) as well as a substantial broadening of research topics. On insects alone, the last 50 years have produced studies which have investigated the genetic and cellular basis for cold tolerance (Marinkovic et al. 1969; Parsons 1973; Tucic 1979; Ring 1980; Lee et al. 1996); specific physiological and biochemical mechanisms that promote cold tolerance (Salt 1961; Somme 1982; Zachariassen 1985; Lee 1991; Storey and Storey 1991); implications for cryopreservation 9 (Morris 1987; Leopold 1991; Steponkus et al. 1991); potential for using insect cold tolerance data as a tool for pest management practices (e.g. long-term population forecasting and the application of natural pesticides which lower insect resistance to colder temperatures) (Bale 1991, Lee et al. 1993); and ecological and evolutionary basis for cold adaptation (Baust and Rojas 1985; Bale 1987; Danks 1978, 1991; Somme and Block 1991). During the past three decades in particular, the ecological and evolutionary basis for cold adaptation in insects has received increasingly significant attention. Many investigations have attempted to correlate laboratory results with conditions in nature to establish ecological relevance (Parsons 1978; Hori and Kimura 1998; David et al. 1998; Kelty and Lee 1999, 2001; Gibert and Huey 2001; Gibert et al. 2001). For example, researchers have assessed cold tolerance in a wide range of species in a variety of developmental stages to better understand overwintering strategies and distribution patterns (Izquierdo 1991; Kimura and Beppu 1993; Kimura et al. 1994; Collett and Jarman 2001). Furthermore, recent studies have more closely examined both short and long-term acclimation responses (Lee et al.