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

[摘要] 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. Pastintroductions of bontebok lead to extensive hybridisation that produced numerous fertile hybrids inthe Free State. The present study aimed at investigating behaviour of introduced herds byquantifying activity budgets and patterns to examine diurnal and seasonal effects on certainbehavioural aspects, allowing comparisons with blesbok. A secondary objective was to determineamplification of ungulate microsatellite primers in D. pygargus. Activity data on bontebok totalling1 098 hours were collected during 2006/2007 and 2009 in the Free State. Observationalmeasurements involved instantaneous scan sampling as well as focal animal sampling. Blesbok andbontebok hair samples were also collected for genetic analysis. Time budgets revealed that equalamounts of time (50%) were spent on active and inactive phases. Grazing and lying were the majoractivities identified and represented more than three quarters (83%) of total observed activities. Lessthan one fifth of their time was diverted to standing (9%) and moving (8%). Behaviour of bontebokdeviated 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 timebudget. The subspecies spent almost equal amounts of time on lying and moving, whereas bontebokallocated more time (6.5%) to grazing and less time (7.5%) to standing. Differences betweenbontebok social groups indicated that females spent the most time grazing (41%) and territorial malesthe least (31%). Juveniles spent nearly half of their time budget on lying and territorial males wereleast 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 withblesbok social groups indicated similarities as well as discrepancies. Territorial rams also spent theleast time grazing, but spent the most time lying. Blesbok juveniles allocated the most time tostanding, however territorial rams also spent the most time on moving behaviour. Bontebokexhibited the same diurnal pattern as blesbok. A typical bimodal feeding pattern with principalgrazing bouts in the early morning and late afternoon and a reciprocal pattern of lying activity aroundmid-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 differenceswere 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 blesbokcan be considered indicative that behavioural differences are insufficient to prevent hybridisationincidents. The occurrence of past hybridisation events can therefore not only be ascribed primarily totheir relatively recent phylogenetic divergence and overlapping breeding seasons, but also as a resultof the convergent behaviour observed in comparable habitats. Following screening of a preliminarypanel of 72 ungulate microsatellite loci a concluding bovine and ovine panel of five microsatellite lociwas identified. Disregarding MAF46 monomorphic pattern for D. p. pygargus, microsatellite locishowed 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 populationranged from one to four. Data obtained not only confirmed that informative polymorphicmicrosatellites can be cross-amplified between closely related representatives of Artiodactyla, butwere also testimony of noteworthy differences in microsatellite allelic variation in D. pygargus. Thesefindings thus represent baseline data that could assist future molecular studies aiming to identifyalleles that would substantiate discrimination between pure and hybrid taxa.

[发布机构] University of the Free State