Integrative taxonomy of the endemic Karoo agile grasshoppers, the Euryphyminae

Tshililo, Precious (2018-03)

Thesis (MScConsEcol)--Stellenbosch University, 2018.

Thesis

ENGLISH ABSTRACT: The Euryphyminae are a small, African subfamily of grasshoppers which are not very well known. They are endemic to sub-Saharan Africa and consist of 23 genera, 16 of which have records of occurrence in South Africa. They are extremely agile and difficult to either catch or spot. Morphologically they are adapted to arid regions. The aim of this study was to use an integrative taxonomy approach to fill gaps in knowledge relating to Euryphyminae taxonomy and diversity in the Karoo biome. I collected all Euryphyminae information from literature and digitized 626 museum specimens which had been positively identified. I also conducted two month-long sampling trips and collected 624 specimens of Euryphyminae in thirty sites across the southern Karoo biome. Utilizing all data at my disposal, I conducted the first taxonomic review of South African Euryphyminae, investigated morphological and molecular variation within one speciose genus, Euryphymus, and analysed the ecology and diversity of Euryphyminae across space and time in the Karoo. In Chapter 2, I investigate the relationships among Euryphyminae genera by comparing morphological characters and molecular markers from three genes. I find that while most Eurphyminae genera are monophyletic and well-resolved, the evolutionary history does not comply with easily visible morphological traits. I provide an updated key to males of the Euryphyminae genera. In Chapter 3, I first classify various individual of genus Euryphymus on the basis of their morphology. I then use DNA barcoding to determine the relationship between individuals with various polymorphism. Results show that individuals group into five valid species using the 3% species divergence cutoff which is most commonly used for insect phylogenetics. Of these five species, some may be new to science and may require species description. This study shows that variation among and within Eurypyhminae genera is very high and that morphology alone may not be sufficient to differentiate among species. Finally, in Chapter 4, I investigate species richness, abundance and species composition of the Euryphyminae across space and time. I find that there are at least two distinct peaks of Euryphyminae abundance containing different species. Futhermore, most Euryphyminae species seem to be localized to a particular place and time, as most Karoo sites were dominated by one Euryphyminae species at a particular time, but this species composition turned over with the different seasons. This ecology seems to be closely tied to the arid ecosystem which Euryphyminae is specially adapted to utilize. As the first ever in-depth study on Euryphyminae, this study reveals that Euryphyminae are diverse and abundant in the Karoo biome. There may be many more as yet undiscovered species, and many of the known genera require taxonomic revision. Taxonomic revision will benefit from utilization of genetic traits. Furthermore, the evolutionary history of the Euryphyminae is not straight-forward and requires investigation to better understand how and when the Euryphyminae became specially adapted to utilize the arid and sparsely inhabited Karoo biome. Results from this study will be analysed in conjunction with results from ten other plant and animal taxa sampled in the same sites through SANBI’s Karoo BioGaps project. As a whole, these data will be used to aid in government decision making for the management and conservation planning of the Karoo, especially as it relates to shale gas exploration or fracking.

AFRIKAANSE OPSOMMING: Die Euryphyminae is ‘n klein, redelik onbekende subfamilie springkane van Afrika. Hulle is endemies aan sub-Saharaanse Afrika en bestaan uit 23 genera waarvan 16 al gevind is in Suid-Afrika. Hulle is besonders rats en moeilik om raak te sien of te vang en is morfologies aangepas tot droë streke. Die doel van hierdie studie was om met gebruik van ‘n geïntegreerde taksonomiese benadering die gapings te vul in die kennis van Euryphyminae taksonomie en diversiteit in die Karoo bioom. Ek het alle inligting oor Euryphyminae van die literatuur verkry en 626 museum eksemplare wat positief identifiseer is, gedigitaliseer. Ek het ook twee insamelings gedoen van twee maande elk waarin ek 624 Euryphyminae eksemplare versamel het vanaf dertig verskillende areas in die suidelike Karoo bioom. Deur al die inligting tot my beskikking te gebruik, het ek die eerste taksonomiese hersiening gedoen van Suid-Afrikaanse Euryphyminae, morfologiese en molekulêre variasie in die genus Euryphymus ondersoek, asook die ekologie en diversiteit van Euryphyminae oor verskillende tydperke en plekke in die Karoo geanaliseer. In hoofstuk 2 ondersoek ek die verhoudings tussen Euryphyminae genera deur morfologiese kenmerke en molekulêre merkers van drie gene. Ek vind dat terwyl die meeste Eurypheminae genera monofileties en goed uiteengesit is, stem die evolusionêre geskiedenis nie ooreen met maklik sigbare morfologiese kenmerke nie. In hoofstuk 3 klassifiseer ek eers tien morfospesies in die genus Euryphymus op grond van hul morfologie. Ek gebruik dan DNS strepieskodering om vas te stel of die tien morfospesies geldige spesies is. Resultate toon dat die tien morfospesies verdeel word in vyf geldige spesies met gebruik van die 3% spesie divergensie afsnypunt wat mees algemeen gebruik word vir insek filogenetiese studies. Van hierdie vyf spesies mag sommiges nuut wees vir die wetenskap en moontlik verdere beskrywing benodig. Die studie toon dat variasie tussen en binne die Euryphyminae genera baie hoog is en dat slegs morfologie moontlik nie voldoende is om tussen spesies te kan onderskei nie. In hoofstuk 4 ondersoek ek spesierykheid, verspreiding en spesie samestelling van die Euryphyminae oor verskillende tydperke en areas. Ek vind dat daar minstens twee duidelike pieke van Euryphyminae getalle is, wat bestaan uit verskilIende spesies. Verder wil dit voorkom of die meeste Euryphyminae spesies gelokaliseer is tot ‘n sekere tyd en plek, omdat die meeste Karoo areas gedomineer was deur een Euryphyminae spesies op ‘n sekere tyd. Hierdie spesie samestelling het egter verander tussen seisoene. Die wil voorkom of hierdie ekologie verbind is aan die droë ekosisteem, waarvoor Euryphyminae spesiaal aangepas is. As die eerste in-diepte studie van Euryphyminae, toon hierdie studie dat Euryphyminae spesieryk en volop is in die Karoo bioom. Daar mag wel baie spesies wees wat nognie beskryf is nie en baie van die bekende genera benodig taksonomiese hersiening. Taksonomiese hersiening sal baat by die gebruik van genetiese kenmerke. Verder is daar gevind dat die evolusionêre geskiedenis van die Euryphyminae nie eenvoudig is nie en meer navorsing benodig word om beter te verstaan hoe en wanneer die Euryphyminae spesiaal aangepas geword het om die droë en yl bewoonde Karoo bioom te benut. Resultate van hierdie studie sal geanaliseer word saam met resultate van tien ander plant en dier taksa wat versamel is in dieselfde areas as deel van SANBI se Karoo BioGaps projek. Hierdie data sal uiteindelik gebruik word om die regering te help met besluitneming oor die bestuur en bewaring van die Karoo, veral ten opsigte van skaliegas eksplorasie en hidrouliese breking.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/103480
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