Using activity patterns and STR markers to distinguish between blesbok (Damaliscus pygargus phillipsi) and bontebok (Damaliscus pygargus pygargus) in the Free State

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Date
2011
Authors
Heyns, Lindi
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Publisher
University of the Free State
Abstract
English: Two subspecies of Damaliscus pygargus, blesbok (D. p. phillipsi) and bontebok (D. p. pygargus), are recognised based on phenotypical and native geographical distribution differences. Past introductions of bontebok lead to extensive hybridisation that produced numerous fertile hybrids in the Free State. The present study aimed at investigating behaviour of introduced herds by quantifying activity budgets and patterns to examine diurnal and seasonal effects on certain behavioural aspects, allowing comparisons with blesbok. A secondary objective was to determine amplification of ungulate microsatellite primers in D. pygargus. Activity data on bontebok totalling 1 098 hours were collected during 2006/2007 and 2009 in the Free State. Observational measurements involved instantaneous scan sampling as well as focal animal sampling. Blesbok and bontebok hair samples were also collected for genetic analysis. Time budgets revealed that equal amounts of time (50%) were spent on active and inactive phases. Grazing and lying were the major activities identified and represented more than three quarters (83%) of total observed activities. Less than one fifth of their time was diverted to standing (9%) and moving (8%). Behaviour of bontebok deviated slightly from blesbok as blesbok allocated more time to lying (40.4%) than to grazing (35.5%), while standing (16.5%) and moving (7.7%) represented nearly a quarter of the general time budget. The subspecies spent almost equal amounts of time on lying and moving, whereas bontebok allocated more time (6.5%) to grazing and less time (7.5%) to standing. Differences between bontebok social groups indicated that females spent the most time grazing (41%) and territorial males the least (31%). Juveniles spent nearly half of their time budget on lying and territorial males were least observed to be lying down (36%). However, territorial rams exhibited much higher standing (19%) and moving (14%) activity compared to any of the other social classes. Comparisons with blesbok social groups indicated similarities as well as discrepancies. Territorial rams also spent the least time grazing, but spent the most time lying. Blesbok juveniles allocated the most time to standing, however territorial rams also spent the most time on moving behaviour. Bontebok exhibited the same diurnal pattern as blesbok. A typical bimodal feeding pattern with principal grazing bouts in the early morning and late afternoon and a reciprocal pattern of lying activity around mid-day were observed. Adverse weather conditions had a seasonal effect on the basic pattern, while grazing and lying time budgets showed significant seasonal differences. Noteworthy differences were thus found regarding bontebok behaviour categories among subsets classified by time of day, season, gender and age. Consistencies between certain behavioural aspects of bontebok and blesbok can be considered indicative that behavioural differences are insufficient to prevent hybridisation incidents. The occurrence of past hybridisation events can therefore not only be ascribed primarily to their relatively recent phylogenetic divergence and overlapping breeding seasons, but also as a result of the convergent behaviour observed in comparable habitats. Following screening of a preliminary panel of 72 ungulate microsatellite loci a concluding bovine and ovine panel of five microsatellite loci was identified. Disregarding MAF46 monomorphic pattern for D. p. pygargus, microsatellite loci showed moderate levels of polymorphism. Allelic variation ranged from one (MAF46) to six (OarFCB304) alleles per locus, with an average allelic diversity of 2.9. Alleles per locus per population ranged from one to four. Data obtained not only confirmed that informative polymorphic microsatellites can be cross-amplified between closely related representatives of Artiodactyla, but were also testimony of noteworthy differences in microsatellite allelic variation in D. pygargus. These findings thus represent baseline data that could assist future molecular studies aiming to identify alleles that would substantiate discrimination between pure and hybrid taxa.
Afrikaans: Twee subspesies van Damaliscus pygargus, blesbok (D. p. phillipsi) en bontebok (D. p. pygargus), word erken op grond van fenotipiese en inheemse geografiese verskille in verspreiding. Bontebok translokasies in die verlede het gelei tot uitgebreide verbastering en gevolglik is daar talle vrugbare hibriede in die Vrystaat voortgebring. Die huidige studie het gepoog om gedrag van ingevoerde troppe te ondesoek deur aktiwiteitsbesteding en patrone te kwantifiseer om sodanig daaglikse en seisoenale effekte op sekere gedragsaspekte te ondersoek, wat vergelykings met blesbok moontlik gemaak het. 'n Sekondêre doelwit was om te bepaal of hoefdier-mikrosatelliet merkers kan amplifiseer in D. pygargus. In totaal is 1098 ure se data van bontebok aktiwiteite verkry gedurende 2006/2007 en 2009 in die Vrystaat. Waarnemings is uitgevoer deur gebruik te maak van die momentskandeermetode sowel as die fokusdier-tegniek. Blesbok en bontebok haarmonsters is ook ingesamel vir genetiese analises. Tydsbegrotings het uitgewys dat gelyke hoeveelhede tyd (50%)op aktiewe en onaktiewe fases spandeer word. Wei en lê gedrag is as die hoof aktiwiteite geïdentifiseer en het meer as 'n driekwart (83%) van die totale waargenome aktiwiteite verteenwoordig. Minder as 'n vyfde van hul tyd is afgestaan aan staan (9%) en beweging (8%). Gedrag van bontebokke het effens afgewyk van blesbok, aangesien blesbokke meer tyd bestee het aan lê (40.4%) as aan weiding (35.5%), terwyl staan (16.5%) en beweging (7.7%) byna 'n kwart van hul algemene tydsbegroting verteenwoordig het. Die subspesies het byna gelyke hoeveelhede tyd spandeer aan lê en beweging, terwyl bontebokke meer tyd (6.5%) aan weiding toegestaan het en minder tyd (7.5%) aan staan. Verskille tussen bontebok sosiale groepe het aangedui dat ooie die meeste wei (41%) en territoriale ramme die minste (31%). lammers het byna die helfde van hul tydsbegroting bestee aan lê en territoriale ramme (36%) was die minste waargeneem om te lê. Territoriale ramme het baie hoër staan (19%) en beweging (14%) aktiwiteite getoon as enige van die ander sosiale groepe. Vergelykings met blesbok sosiale groepe het ooreenkomste sowel as verskille aangedui. Territoriale ramme het ook die minste tyd aan weiding bestee, maar het die meeste tyd bestee aan lê. Blesboklammers het meer tyd toegestaan aan staan, maar territoriale ramme het ook die meeste tyd op bewegingsgedrag spandeer. Bontebokke het dieselfde daaglikse patroon as blesbokke getoon. 'n Tipiese bimodale voedingspatroon met die hoof weidingspieke in die vroeë oggend en laatmiddag en 'n wedersydse patroon van lê-aktiwiteit gedurende die middel van die dag is waargeneem. Ongunstige weerstoestande het 'n seisoenale uitwerking op die basiese patroon getoon, terwyl wei en lê tydsbegrotings beduidende seisoenale verskille getoon het. Noemenswaardige verskille is dus gevind met betrekking tot gedragskategorieë geklassifiseer deur tyd van die dag, seisoen, geslag en ouderdom. Konsekwentheid tussed sekere gedragsaspekte van bontebokke en blesbokke kan beskou word as 'n aanduiding dat gedragsverskille onvoldoende is om hibridisasie gebeure te voorkom. Die voorkoms van hibridisasie gevalle in die verlede kan dus nie alleenlik toegeskryf word aan hul relatiewe onlangse filogenetiese divergensie en gedeeltelike oorvleueling van hul teelseisoene nie, maar ook as gevolg van konvergerende gedrag wat waargeneem word in soortgelyke habitats. Nadat 'n voorlopige paneel van 72 hoefdier-mikrosatelliet merkers getoets was is 'n finale bees en skaap paneel bestaande uit vyf mikrosatelliet merkers geïdentifiseer. Uitsluitend MAF46 wat monomorfies is vir D. pygargus, is matige vlakke van polimorfisme getoon. Alleliese variasie het gewissel van een (MAF46) tot ses (OarFCB304) allele per lokus, met 'n gemiddelde alleliese diversiteit van 2.9. Allele per lokus per bevolking het gewissel van een tot vier. Verkrygde data bevestig nie net dat insiggewende polimorfiese mikrosatelliete kan kruis-amplifiseer tussen naverwante verteenwoordigers van Artiodactyla nie, maar is ook getuienis van noemenswaardige verskille van mikrosatelliet alleliese variasie profiele in D. pygargus. Hierdie bevindinge verteenwoordig dus basis data wat kan bydra tot toekomstige molekulêre studies met die doelom allele wat diskriminasie tussen suiwer en hibried taksa staaf, te identifiseer.
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Keywords
Damaliscus pygargus, Translocation, Subspecies, Hybridisation, Morphometrics, Activity time budget, Diurnal pattern, Alleles, Genotype, Dissertation (M.Sc. (Zoology and Entomology))--University of the Free State, 2011, Microsatellite markers
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