• Admin
    UC Research Repository
    View Item 
       
    • UC Home
    • Library
    • UC Research Repository
    • College of Science
    • Science: Theses and Dissertations
    • View Item
       
    • UC Home
    • Library
    • UC Research Repository
    • College of Science
    • Science: Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of the RepositoryCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    Statistics

    View Usage Statistics

    Behavioural displays, acoustic and chemosensory communication in the Middle Island tusked weta, Motuweta isolata (Orthoptera: Anostostomatidae)

    Thumbnail
    View/Open
    thesis_fulltext.pdf (8.866Mb)
    Author
    Guignion, Cassandra Ann
    Date
    2005
    Permanent Link
    http://hdl.handle.net/10092/1408
    Thesis Discipline
    Zoology
    Degree Grantor
    University of Canterbury
    Degree Level
    Masters
    Degree Name
    Master of Science

    Three methods of communication were examined in the Middle Island tusked weta, Motuweta isolata (Orthoptera: Anostostomatidae); defence behaviour, acoustic and chemosensory signalling. Previous studies had been limited to basic autecology and anecdotal evidence. This study was undertaken to understand the behaviours of this species to assist in conservation efforts. Defensive behaviours were elicited through repeated stimulation while aggressive behaviours were acquired through male-male battles. Femoro-abdominal stridulation was induced within both situations. Defensive stridulation functioned as alarm behaviour and was often accompanied by a visual display. Agonistic stridulation was executed by the eventual winner of combat. Aggressive battles were a progression of behavioural units of increasing risk on injury until an individual was determined the winner. Acoustic analysis was preformed on stridulations observed in aggressive and defensive behaviours. Stridulation was a broad band signal covering a range well above 16 kHz and possibly into the ultrasound range (>20 kHz). Two different forms of stridulation were identified; click train sound and hiss sound. High speed frame-by-frame analysis of stridulation and scanning electron micrographs of the abdomen and medial femur deciphered the mechanism and found the interaction of the cuticle to be unique among weta. Strikingly, micrographs also revealed two morphologies of abdominal projections; truncated ridges and columnar pegs. Both these points were not previously observed. Y-maze and partition tests were utilized for evidence of chemosensory signalling, while gas chromatography-mass spectrometry identified faecal volatiles in M. iisolata and 4 other weta species in a parallel study. Through partition experiments, evidence exists for a species-specific volatile pheromone and a sex-specific chemo-tactile pheromone. Dimethylsulphide, (CH3)2S, was present in the faeces of all 5 weta species, and may be produced by the individual.

    Subjects
    weta
     
    Motuweta isolata (Orthoptera: Anostostomatidae)
     
    defence behaviour
     
    acoustic signalling
     
    chemosensory signalling
    Collections
    • Science: Theses and Dissertations [3298]
    Rights
    http://library.canterbury.ac.nz/thesis/etheses_copyright.shtml

    UC Research Repository
    University Library
    University of Canterbury
    Private Bag 4800
    Christchurch 8140

    Phone
    364 2987 ext 8718

    Email
    ucresearchrepository@canterbury.ac.nz

    Follow us
    FacebookTwitterYoutube

    © University of Canterbury Library
    Send Feedback | Contact Us