Anisota Virginiensis Drury) (LEPIDOPTERA: SATURNIIDAE)
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Lakehead University Knowledge Commons,http://knowledgecommons.lakeheadu.ca Electronic Theses and Dissertations Undergraduate theses 2021 A morphological comparison of two Canadian populations of the pink striped oakworm (Anisota virginiensis Drury) (LEPIDOPTERA: SATURNIIDAE) Hensrud, Claire B. http://knowledgecommons.lakeheadu.ca/handle/2453/4765 Downloaded from Lakehead University, KnowledgeCommons A MORPHOLOGICAL COMPARISON OF TWO CANADIAN POPULATIONS OF THE PINK STRIPED OAKWORM (Anisota virginiensis Drury) (LEPIDOPTERA: SATURNIIDAE) by Claire B. Hensrud FACULTY OF NATURAL RESOURCES MANAGEMENT LAKEHEAD UNIVERSITY THUNDER BAY, ONTARIO APRIL 2021 ii A MORPHOLOGICAL COMPARISON OF TWO CANADIAN POPULATIONS OF THE PINK STRIPED OAKWORM (Anisota virginiensis Drury) (LEPIDOPTERA: SATURNIIDAE) by Claire B. Hensrud An Undergraduate Thesis Submitted in Partial Fulfilment of the Requirements for the Degree of Honours Bachelor of Environmental Management Faculty of Natural Resources Management Lakehead University April 2021 Dr. Don Henne Ryan Wilkie Major Advisor Second Reader iii LIBRARY RIGHTS STATEMENT In presenting this thesis in partial fulfilment of. the requirements for the HBEM degree at Lakehead University in Thunder Bay, I agree that the University will make it freely available for inspection. This thesis is made available by my authority solely for the purpose of private study and may not be copied or reproduced in whole or in part (except as permitted by the Copyright Laws) without my written authority. Signature: Date: April 15, 2021 iv A CAUTION TO THE READER This HBEM thesis has been through a semi-formal process of review and comment by at least two faculty members. It is made available for loan by the Faculty of Natural Resources Management for the purpose of advancing the practice of professional and scientific forestry. The reader should be aware that opinions and conclusions expressed in this document are those of the student and do not necessarily reflect the opinions of the thesis supervisor, the faculty or of Lakehead University. v ABSTRACT Keywords: Anisota virginiensis, Anisota, morphology, pink-striped oakworm, wingspan, body length This thesis involves a morphological and physiological comparison of two Canadian populations (Manitoba and Nova Scotia), and several USA populations of adult pink-striped oakworm (Anisota virginiensis) moths. It was hypothesized that there would be no significant differences in morphological characteristics of these adult moths (i.e., body length, wingspan, and colouration). Adult moth body lengths and wingspans were measured. By using a series of t-tests none of the populations were deemed to be significantly different. However there appears to be a modest trend towards smaller adult moths from northern and western parts of the range of this moth. Additionally, adult wing colouration was quite different amongst populations. Further research using mDNA procedures may indicate that certain populations of the pink-striped oakworm are new species. vi ACKNOWLEDGEMENTS I would like to thank Dr. Don Henne for allowing me the opportunity to work on this project with him, and for all of his assistance and guidance throughout this process. I would also like to thank Ryan Wilkie for taking the time to be my second reader, my parents, Ole and Candi, and my fiancé Derian for always motivating me to do my best and helping me achieve my goals, as well as my dog Onni for the countless hours of company while I completed this study. vii CONTENTS LIBRARY RIGHTS STATEMENT iii A CAUTION TO THE READER iv ABSTRACT v ACKNOWLEDGEMENTS vi CONTENTS vii TABLES viii FIGURES ix INTRODUCTION 1 LITERATURE REVIEW 3 MATERIALS AND METHODS 11 RESULTS 14 DISSCUSSION 27 CONCLUSION 29 ACKNOWLEDGEMENTS 30 LITERATURE CITED 31 viii TABLES Table Page 1. List of Anisota species and their distribution. 10 2. Wingspans and body lengths (in mm) of adult female A. virginiensis 14 from the Manitoba and Nova Scotia populations. 3. Wingspans and body lengths (in mm) of adult male A. virginiensis 15 from the Manitoba and Nova Scotia populations 4. Wingspans and body lengths (in mm) of adult female Anisota from 15 the United States. 5. Wingspans and body lengths (in mm) of adult male Anisota from the 16 United States. 6. Two-tailed t-test table of male body lengths. 16 7. Two-tailed t-test table of male wingspans. 17 8. T-test table of female body length. 17 9. T-test table of female wingspans. 18 10. T-test table of Manitoban and USA female body lengths. 18 11. T-test of Manitoban and USA female wingspans. 19 12. T-test of Manitoban and USA male body lengths. 19 13. T-test of Manitoban and USA male wingspans. 20 14. T-test of Nova Scotian and USA female body lengths. 20 15. T-test of Nova Scotian and USA female wingspans. 21 16. T-test of Nova Scotian and USA male body lengths. 21 17. T-test of Nova Scotian and USA male wingspans. 22 ix FIGURES Figure Page 1. Anisota virginiensis moths from Nova Scotia. Male (left) and 4 female (right). 2. Anisota virginiensis caterpillars from Nova Scotia (left) and 4 Manitoba (right) 3. Range map of bur oak (Quercus macrocarpa). 7 4. Range of red oak (Quercus rubra). 8 5. Range map of genus Anisota. 9 6. Map showing location of Belair, Manitoba. 12 7. Map showing location of Mount Uniake, Nova Scotia 13 8. Manitoba male (left), Nova Scotia male (right) 23 9. Manitoba female (left), Nova Scotia female (right) 24 10. Anisota virginiensis caterpillars from Nova Scotia (left) and 24 Manitoba (right) 11. Manitoba male moth (left) and USA male moth (right) 25 12. Nova Scotia male moth (left) and USA male moth (right) 26 13. Manitoba female moth (left) and USA female moth (right) 26 14. Nova Scotia female moth (left) and USA female moth (right) 27 1 INTRODUCTION The pink-striped oakworm, Anisota virginiensis (Drury), is a member of the class Insecta, order Lepidoptera, and family Saturniidae (Burke and Peigler 2009). Oakworms are a term commonly used to refer to caterpillars of the genus Anisota. The genus Anisota includes ten known species that occur in the eastern portion of North America and six other species occurring in the southwest of North America and in Mexico (Burke and Peigler 2009). Oakworms can be found throughout central and eastern North America in green spaces such as forests, yards, and parks. As the common name implies, they are known to occasionally cause severe oak (Quercus spp.) defoliation (Burke and Peigler 2009). From time to time, caterpillars of some species of Anisota can become pests and severe infestations amongst oak species can occur. A. virginiensis typically does not become abundant enough to become a pest, although it has caused severe defoliation of oaks within Manitoba, Ontario, and Quebec (Henne 2004). The genus Anisota includes brownish coloured moths that vary from small to medium in size. There is a white spot on the forewing and sexual dimorphism is typically strong within the species (Riotte and Peigler 1980). A. virginiensis is a member of the A. pellucida group, which includes A. virginiensis, A. pellucida, and A. discolor, but some authors consider all three species to be synonymous with A. virginiensis (Tuskes et al. 1996). This group is determined through larval characteristics and adult moth habitats as well as the geographical distributions of the component species. Other groups include A. stigma, A. senatoria, and the Mexican groups (Riotte and Peigler 1980). 2 Anisota virginiensis caterpillars are mostly gray in colour and are covered with numerous white specks, and several rows of pink stripes run longitudinally down its body (Ferguson 1971). The moths of A. virginiensis are a pinkish-purplish colour. The males are diurnal, where the females are nocturnal (Ferguson 1971). In this study, with the assistance of Dr. Don Henne, I will look at two widely separated Canadian populations of A. virginiensis; one from Manitoba, Canada and the other from Nova Scotia, Canada. These two populations will be compared morphologically in order to determine whether or not these are in fact two different species rather than one variable species. The population samples were collected by Dr. Henne in June of 2019 from both Belair Resort, Manitoba and Mount Uniake (Hants County), Nova Scotia. The caterpillars from Manitoba were reared from eggs collected from Bur Oak (Quercus macrocarpa), while eggs from Nova Scotia were obtained from a wild female collected in June of 2019. The adults of both populations emerged in the laboratory during early June of 2020. A number of fifth-instar caterpillars from the two populations were put into 95% ethanol and frozen for later DNA analysis. The objective of my thesis is to examine two widely separated Canadian populations of A. virginiensis, as well as several USA populations from Dr. Henne’s personal collection. This will be done through a series of body and wingspan measurements. It is hypothesized that there is a difference in the phenotypic traits between the Manitoba and Nova Scotia populations of A. virginiensis. 3 LITERATURE REVIEW THE GENUS Anisota The genus Anisota is member of the family Saturniidae. The Saturniidae encompass some of the largest and showiest moths in North America (Tuskes et al. 1996). There are approximately 1200 species and more than 125 genera of Saturniidae worldwide, but only 18 genera and about 70 species occur north of Mexico (Tuskes et al. 1996), with one genus being Anisota. Anisota encompasses the smallest members of Saturniidae in North America (Ferguson 1971). The species within the genus Anisota have a white discal spot on their forewing, as well as a prominent apical spine on their front legs (Ferguson 1971). The caterpillars of Anisota are commonly known as oakworms. These caterpillars can be found throughout central and eastern North America in green spaces such as forests, yards and parks (Burke and Peigler 2009).