The preferred habitat of the jack jumper ant (Myrmecia pilosula)

185 Pages·2014·56.98 MB·English

The preferred habitat of
the jack jumper ant
(Myrmecia pilosula)
A study in Hobart, Tasmania
Maldwyn John Evans BSc (Hons), Grad. Dip. Environmental Studies
University of Tasmania
A thesis submitted in partial fulfillment of the requirements for a Master of Environmental
Management at the School of Geography and Environmental Studies, University of
Tasmania (July 2008).
Declaration
This thesis contains no material which has been accepted for the award of any other degree
or diploma in any tertiary institution, and to the best of my knowledge and belief, contains
no material previously published or written by another person, except where due reference
is made in the text of the thesis.
Signed
Maldwyn John Evans
Wednesday, July 02, 2008
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Dedication
This thesis is dedicated to my grandparents, Maldwyn and Megan Evans.
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Abstract
The jack jumper ant (Myrmecia pilosula), a member of the primitive Myrmecia genus of
ants, is well known for its aggressive behaviour and painful, sometimes dangerous sting.
However, although the ant is well known to Tasmanians, there are few published studies of
its biology or ecology. This project is an attempt to address this lack of research and seeks
to explore the interaction between humans and jack jumpers by understanding better the
preferred habitat of the ant.
Two studies were undertaken within the boundaries of the study area: Hobart City Council,
Tasmania, Australia. In the first study, jack jumper nests were searched for ten times in
transects, in each of the natural vegetation types. Data were collected on the presence or
absence of jack jumper nests, vegetation type, vegetation structure, moss cover, bare
ground cover, coarse woody debris cover, rock cover, litter cover, litter depth, and distance
to nearest tree as well as observations made about each nest that was found. In the second
study, residents of Hobart were surveyed using a questionnaire regarding the features of
their property and whether they had ever seen a jack jumper nest or ant on their property.
They were also asked to outline the circumstances in which they were stung. To analyse the
data, thematic analyses, correlation analyses, analysis of variance, Wilcoxon tests, chi-
square testing, logistic regression and ordination were used.
The results of the study showed that, within the Hobart City Council boundary, jack jumpers
are co-extensive with dry eucalypt open woodlands. These warm, dry and relatively open
environments provide the ant with a combination of insolation for warmth and vegetation
for food resources such as nectar and invertebrate prey. They also utilise the radiative
warmth of rocks and dry soil and often. enhance their nest's thermal capacity with
decorations of seeds, soil, charcoal, stones, sticks and sometimes small vertebrate bones. In
a suburban context the ants are associated with native vegetation whilst utilising cracks in
concrete, walls, rockeries, dry dirt and dry grassy areas to construct nests. The suburbs with
a significant matrix of native vegetation such as Mt. Nelson, Fern Tree and West Hobart all
contain the ants, whereas the heavily built up areas of Battery point and North Hobart do
not.
Humans are most likely to be stung by a jack jumper ant in their property when carrying out
outdoor duties such as gardening or collecting firewood. They may also be stung whilst
walking bare foot. A Common sense approach should be employed in order to avoid a sting
from a jack jumper. For those wishing to live in areas that do not contain the ant, the built
up suburbs of Hobart are recommended.
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"...at the first alarm they come jumping out from the side door of
their raised mound,... one after the other, like a pack of dogs, and
fasten onto the first thing they come across; as there is usually a
large opening in the top of the nest, the unwary investigator, who
has not learned about the side door, generally discovers it
through a rear attack when the jumpers swarm up his legs and
begin their investigations."
(Froggatt 1905 in Wheeler 1910, p. 229)
(Above ana cover photographs: Felix Wilson)
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Acknowledgements
I would like to thank my supervisor, Dr. Peter McQuillan, for his ideas, enthusiasm and
support throughout the project; Dr. Emma Pharo for her invaluable editing in the final
months of the thesis; Dr. Michael Lockwood, for his advice, approachability and
understanding during the project; Prof. Jamie Kirkpatrick for his advice, laughter and plant
identification during the project; Dennis Charlesworth and Dave Green for use of the
School's equipment; Rob Anders and the Department of Primary Industries and Water for
providing me with the GIS data; Darren Turner, for help analysing the canopy cover photos;
Kristin Warr for logistical support; Maria Fletcher from Ant Allergy for her help with the
questionnaire and enthusiasm about my work; Cherie Cooper for helping me engage the
Tasmanian media; Grant Daniels for generously offering his data and helping me gain more
participants; Alex Wild, for letting me use his photo of a jack jumper; Felix Wilson for his
dogged determination in the quest for the perfect jack jumper photo; Chantal Binding,
Jasper Evans, Tania King, Sam 'big feller' Wood and Geoff States for helping me with ant
surveys; lain 'the lesser of two weevils' Mackay for the photo of jack jumper nuptials; Mayo
Kajitani for her expert help with GIS; Joanne McMillan for her love and support at every
step of the project; Jane and Simon McMillan, for whom without, I wouldn't have been able
to complete this degree; my family for their support from afar; and finally, the participants
of the survey, without which, I could not have completed this project.
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Table of Contents
Declaration
Dedication
Abstract iv
Acknowledgements vi
List of Figures xii
List of Tables xv
1 Introduction 1
1.1 Venomous animals 1
1.2 Hymenoptera stings 1
1.3 Jack jumper ant (Myrmecia pilosula) stings 2
1.4 Treatment and prevention — a brief review 3
1.4.1 Adrenaline and other medications 3
1.4.2 Venom immunotherapy (VIT) 4
1.4.3 Prevention 4
1.5 Research aims 5
1.6 Overview of the study 5
2 Background 6
2.1 Previous work on Myrmecia pilosula 6
2.2 Biology and Ecology of Myrmecia pilosula 7
2.2.1 Phylogeny of Myrmecia pilosula 7
2.2.2 Evolutionary history of Myrmecia pilosula 8
2.2.3 Morphology of Myrmecia pilosula 9
2.2.4 The colony life cycle 9
2.2.5 Life in the colony 12
2.2.6 Recruitment 12
2.2.7 Foraging 13
2.2.8 Pollination 13
2.3 The preferred habitat of Myrmecia pilosula 13
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2.4 Habitat preference of other ant species 15
2.4.1 Ants, vegetation and moisture 15
2.4.2 Ants and altitude 17
2.4.3 Ants, disturbance and urbanisation 17
2.5 Nest architecture studies 18
2.6 Research questions 19
3 Research Design 20
3.1 The study area 20
3.1.1 Overview 20
3.1.2 Climate 21
3.2 Study design 23
3.3 Nest survey 24
3.3.1 Hobart's bushland 24
3.3.2 Vegetation types 30
3.3.3 Sampling the jack jumper ant 30
3.3.4 Season, Time and Weather 32
3.3.5 Transect sites 32
3.3.6 Vegetation 33
3.3.7 Plant identification 34
3.3.8 Soil 34
3.3.9 Other environmental variables 36
3.3.10 Canopy cover photographs 36
3.3.11 Finding a nest 37
3.3.12 Risk Assessment 37
3.4 Nest survey data analyses 37
3.4.1 Correlation 38
3.4.2 Chi-square testing 38
3.4.3 Analysis of variance (ANOVA) and Wilcoxon test on ranks 39
3.4.4 Logistic regression 39
3.4.5 Ordination 40
3.5 Hobart properties survey 40
3.5.1 The questionnaire 41
3.5.2 Selection and recruitment of participants 42
3.5.3 Ethical clearance 43
3.6 Hobart properties survey data analysis 43
4. Results 45
4.1 Nest survey 45
4.1.1 Vegetation type and structure 45
4.1.2 Environmental variables 47
4.1.3 Nest characteristics 58
4.2 Hobart Properties survey 63
4.2.1 Responses 63
4.2.2 Section A: The participant's property 63
4.2.3 Section B: Jack jumpers on the participant's property 67
4.2.4 Section C: The participant's address 72
5 Discussion 78
5.1 What environmental conditions do Myrmecia pilosula prefer to nest in? 78
5.1.1 Vegetation type and structure 78
5.1.2 Habitat complexity 81
5.1.3 Altitude 83
5.1.4 The importance of vegetation for food 83'
5.2 What are the characteristics of a typical Myrmecia pilosula nest? 84
5.2.1 Materials and location of nest 84
5.2.2 Nest decoration and mound 85
5.2.3 Plants associated with nest 87
5.3 How does Myrmecia pilosula respond to urbanisation? 88
54 What habitats increase the risk of humans receiving a sting from Myrmecia pilosula
and how could this risk be reduced? 90
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5.4.1 Avoidance 90
5.4.2 Habitat management ' 91
5.5 Speculations 91
5.6 Limitations and biases 93
5.7 Recommended future research 95
5.8 Conclusions 95
References 97
Appendix I TASVEG Communities Summary (DPIW Tasmania 2007; Harris & Kitchener
2005) 109

Appendix II Nest survey prof orma 111
Appendix III Hobart properties survey questionnaire 114
Appendix IV Hobart properties survey questionnaire cover sheet 119
Appendix V Ethics approval documents 122
Appendix VI UTas media release 129
Appendix VII Media engagement report 131
Appendix VIII Nest survey data sheet — vegetation type and structure 135
.
Appendix IX Nest survey data sheet — environmental variables 143
Appendix X Nest survey data sheet — First nest recordings 149
Appendix XI Nest survey data sheet — control recordings 150
Appendix XII Hobart properties survey data sheet — participants' estimates 151
Appendix XIII Hobart properties survey data sheet — circle environmental estimates 152
Appendix XIV Nest survey — complete correlation table 153
Appendix XV Nest survey - Non-parametric correlation test of environmental variables
(Spearman p) 154
Appendix XVI Non- parametric correlation test (Spearman p) of first nest and control
variables 160
Appendix XVII Non-parametric correlation test (Spearman p) of participant's estimates....
161
Appendix XVIII Non-parametric correlation test (Spearman p) of the circle environmental
variables and distance to native vegetation 162