Thesis (MScAgric)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Cydia pomonella (codling moth), Thaumatotibia leucotreta (False codling moth), Thaumatotibia
batrachopa (Macadamia nut borer), Grapholita molesta (Oriental fruit moth), Cryptophlebia peltastica
(Litchi moth), Epichoristodes acerbella (Pear leafroller/Carnation worm) and Lozotaenia capensana (Apple
leafroller) are the most economically important tortricids affecting various crops in South Africa. The
correct identification of these species, especially of the larval stage, is of great importance in pest
management. Using available literature, augmented by additional morphological studies, an interactive
identification key (Lucid key) for larval and adult stages of the seven species was developed. The colour
and markings of the head, characteristics of the prothoracic and anal shields, the position of the
prespiracular setae (L-group) relative to the spiracle on the prothoracic segment, the position of the spiracle
on the eighth abdominal segment and L-group on the ninth abdominal segment, as well as the presence or
absence of the anal comb are key characteristics for larval identification. For adult identification, wing
pattern and genitalia are the most important features. However, the use of genitalia for moth identification
might be difficult for the lay user, as the dissection and mounting of these structures requires certain skills
and specialized equipment. Thus, genitalia have not been included in the Lucid Key. Differences in the
morphological characteristics of most pupae were so minute that this stage was also not included in the
Lucid key. However, the pupae of E. acerbella and L. capensana are easily distinguished from those of the
other species by the presence of acremaster. This study also included the first morphological description of
the pupa of L. capensana, which can be distinguished from that of E. acerbella by various features of the
cremaster, antennae, spiracle shape, number of setae on abdominal segments A5-7, the size of spines on
A3-7, and the presence/absence of spines on A9. A previous study by Timm (2005) indicated that
geographically isolated populations of T. leucotreta tend to be genetically distinct. This raised the question
of whether speciation/subspeciation has occurred or is occurring. Male moth genitalia are thought to evolve
rapidly and are often the only features that can reliably distinguish similar species. Hence, variation in the
shape of the valvae of T. leucotreta was used to determine whether divergence has occurred between
populations of T. leucotreta. Elliptical Fourier analysis was used to analyze the valvar variation in three
different populations. Although some variation in valvar shape was detected among mean population values
for certain traits, no clear pattern emerged. Principle component analysis also showed no distinct clustering
of valvae shape among populations, providing no evidence for divergence in male genitalia and therefore
no morphological evidence of incipient speciation. / AFRIKAANSE OPSOMMING: Cydia pomonella (Kodlingmot), Thaumatotibia leucotreta (Valskodlingmot), T. batrachopa
(Makadamianeutboorder), Grapholita molesta (Oosterse vrugtemot), Cryptophlebia peltastica
(Lietsjiemot), Epichoristodes acerbella (Peerbladroller/Angelierrusper) en Lozotaenia capensana
(Appelbladroller) is die mees ekonomies belangrike tortrisiede van die vrugtebedryf in Suid-Afrika. Die
juiste identifikasie van hierdie spesies, veral van hulle larwale stadium, is van groot belang by plaagbestuur.
Deur gebruik te maak van beskikbare literatuur, aangevul deur bykomstige morfologiese studies, is ‗n
interaktiewe uitkenningssleutel (―Lucid key‖) vir die larwale en volwasse stadia van die sewe spesies
ontwikkel. Die kleur en tekening van die kop, kenmerke van die prothorakale en anale skild, die ligging
van die prespirakulêre setae (L-groep) relatief tot die spiraculum op die prothorakale segment, die ligging
van die spirakulum op die agste abdominale segment en L-groep op die negende abdominale segment,
asook die aan- of afwesigheid van die anale kam is sleutel kenmerke vir larwale uitkenning. Vir die
volwassenes is die vlerktekening en genitalia die mees belangrike kenmerke. Die gebruik van die genitalia
vir motuitkenning kan egter vir die leek gebruiker moeilik wees omdat die disseksie en montering van
hierdie strukture bepaalde vaardighede en gespesialiseerde toerusting vereis. Vir die rede is die genitalia
nie in die Lucid-sleutel ingesluit nie. Verskille in die morfologiese kenmerke van meeste papies is klein en
die stadium is gevolglik ook nie in die sleutel ingesluit nie. Die papies van E. acerbella en L. capensana
kan egter maklik van die ander spesies onderskei word deur die aanwesigheid van ‗n cremaster. Hierdie
studie sluit ook die eerste morfologiese beskrywing van die papie van L. capensana in, wat van dié van E.
acerbella onderskei kan word deur gebruik te maak van kenmerke van die cremaster, antennae, spirakulêre
vorm, aantal setae op abdominale segmente A5-7, die grootte van stekels op A3-7, en die aan- of
afwesigheid van stekels op A9. ‗n Vroeëre studie (Timm 2005) het aangedui dat geografies geïsoleerde
bevolkings van T. leucotreta neig om geneties verskillend te wees. Dit het die vraag laat ontstaan of
spesiasie/subspesiasie moontlik plaasgevind het of steeds plaasvind. Manlike mot genitalië word geag om
vinnig te ontwikkel en is dikwels die enigste kenmerke wat betroubaar tussen soortgelyke spesies kan
onderskei. Dus is die variasie in die vorm van die valvae van T. leucotreta gebruik om te bepaal of
divergensie wel tussen bevolkings van T. leucotreta plaasgevind het. Elliptiese Fourier ontleding is gebruik
om die valvae se variasie by drie verskillende bevolkings te ontleed. Alhoewel enkele variasie in die vorm
van die valvae bespeur is by die gemiddelde bevolkingswaardes vir bepaalde eienskappe, kon geen
duidelike patroon bespeur word nie. Hoofkomponentontleding het ook geen duidelike groepering van
valvae se vorm tussen bevolkings getoon nie, wat geen bewys lewer van divergensie in die manlike
genitalia en dus geen morfologiese bewys van beginnende spesiasie.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/79825 |
| Date | 03 1900 |
| Creators | Rentel, Monique |
| Contributors | Addison, P., Geertsema, H., Brown, J. W., Stellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | xiii, 133 p. : ill. |
| Rights | Stellenbosch University |
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