Torsten Wronski

Home-range overlap, social vicinity and agonistic interactions denoting matrilineal organisation in bushbuck, Tragelaphus scriptus

In matrilineal species, females and their offspring are organised within a group along lines of female kinship, i.e. matrilines or natal breeding groups. In some gregarious artiodactyles, daughters remain associated with their mothers into adulthood. To test this on a solitary living artiodactyle, the bushbuck (Tragelaphus scriptus), home-range overlap, social vicinity and differentiated social relations between related and non-related females were used as indicators for the existence of matrilineal structures. Results of numerical classification and matrix correlation of social and spatial vicinity were matched with known kin relations indicating the existence of natal breeding groups among females. An extended home-range overlap between kin suggested restricted movements of females and therefore a female residence or philopatry. Differentiated and consistent female relationships signified matrilineal structures and suggested a competitive regime between female clans. We therefore conclude that complex kinship structures also exist in non-gregarious ungulate species.

Two reciprocally monophyletic mtDNA lineages elucidate the taxonomic status of Mountain gazelles (Gazella gazella)

Mountain gazelles (Gazella gazella) rank among the most critically endangered mammals on the Arabian Peninsula. Past conservation efforts have been plagued by confusion about the phylogenetic relationship among various ‘phenotypically discernable’ populations, and even the question of species boundaries was far from being certain. This lack of knowledge has had a direct impact on conservation measures, especially ex situ breeding programmes, hampering the assignment of captive stocks to potential conservation units. Here, we provide a phylogenetic framework, based on the analysis of mtDNA sequences (360 bp cytochrome b and 213 bp Control Region) of 126 individuals collected from the wild throughout the Arabian Peninsula and from captive stocks. Our analyses revealed two reciprocally monophyletic genetic lineages within the presumed species Gazella gazella: one ‘northern clade’ on the Golan Heights (Israel/Syrian border) and one genetically diverse larger clade from the rest of the Arabian Peninsula including the Arava Valley (Negev, Israel). Applying the Strict Phylogenetic Species Concept (sensu Mishler & Theriot, 2000) allows assigning species status to these two major clades.

The communicatory significance of localised defecation sites in bushbuck (Tragelaphus scriptus)

Like several other mammals, bushbuck (Tragelaphus scriptus) deposit faeces in specific localised defecation sites (LDS). A previous study has ruled out a function of LDS in the context of parasite avoidance. In this study, we investigated the communicatory significance of LDS. In a free ranging population, we tested whether LDS serve to demarcate home ranges, and/or if LDS are used for communication in a non-territorial context. In both sexes, LDS increased significantly in number towards the periphery of individual home ranges. However, the distribution pattern of LDS, as revealed by a nearest-neighbour mapping technique (nearest distances between LDS), did not support the idea that LDS serve home range/territory-demarcation because LDS did not follow a pattern of minimal nearest-neighbour distances along the margins of home ranges. We found females to urinate more often in LDS than males. Notably, information transfer was most frequent between sending (urinating or defecating) females and receiving/responding males (urination or defecation at places where a female had previously signalled). Our results suggest that LDS mainly serve for inter-sexual communication in bushbuck.

Phylogenetic analysis of mitochondrial DNA sequences reveals polyphyly in the goitred gazelle (Gazella subgutturosa)

Goitred gazelle (Gazella subgutturosa) rank among the most endangered mammals on the Arabian Peninsula and the Asian steppes. Past conservation efforts have been plagued by confusion about the phylogenetic relationship among various—phenotypically discernable—populations, and even the question of species boundaries was far from being certain. This lack of knowledge had a direct impact on conservation measures, especially ex situ breeding programmes, hampering the assignment of captive stocks to potential conservation units. Here, we provide a phylogenetic framework, based on the analysis of mtDNA sequences of a number of individuals collected from the wild and captivity throughout the species’ natural range. Our analyses revealed a polyphyly within the presumed species of G. subgutturosa resulting in two distinct clades: one on the Arabian Peninsula, Iraq, Jordan, Syria and Turkey (Gazella marica; sand gazelle) and one genetically diverse larger clade from the rest of its Asian range (G. subgutturosa; goitred gazelle). Additionally, we provide a quick method (PCR-RFLP) to analyse the taxonomic affiliation of captive gazelles that will be used for re-introductions into the wild.

Activity patterns of bushbuck (Tragelaphus scriptus) in Queen Elizabeth National Park.

Activity patterns and time budgets of bushbuck (Tragelaphus scriptus) were studied in a free-ranging population in Queen Elizabeth National Park, Uganda from August 2000 to January 2002. We investigated differences in activity patterns in relation to daytime, season, sun radiation, moonlight, age and sex. Bushbuck were found to show peak activities around sunrise and at dawn. No difference in the mean activity rates was found between the dry and wet season. Daytime activity was not predicted by differences in sun radiation, nor was nighttime activity predicted by the presence or absence of moonlight. We found the activity of adult territorial males to be strongly positively correlated with that of females, whereas the activity of young-adult non-territorial males was not significantly correlated with the activity of females. This suggests that young-adult males shift their peak activity to phases when adult territorial males are less active.

Localised defecation sites: a tactic to avoid re-infection by gastro-intestinal tract parasites in bushbuck, Tragelaphus scriptus?

Bushbuck (Tragelaphus scriptus) often deposit faeces at specific localised defecation sites (LDS). We tested whether LDS have a function in the context of parasite avoidance. In a population of bushbuck in Queen Elizabeth National Park, Uganda, seven radio-collared individuals were observed. We recorded feeding behaviour inside and outside LDS. Furthermore, pasture contamination with gastro-intestinal tract parasites inside and outside LDS was examined. There were significant differences between the expected and the observed feeding rates inside LDS, but, contrary to our prediction, the bushbuck increased their feeding rate inside LDS. There was no significant difference in the parasite contamination of pastures inside and outside LDS. We discuss the hypothesis that LDS mainly serve a social function in bushbuck communities, whereas parasite avoidance seems to play a minor or no role.

Behavioural repertoire of the bushbuck (Tragelaphus scriptus): agonistic interactions, mating behaviour and parent–offspring relations

A free-ranging bushbuck (Tragelaphus scriptus) population was observed over a period of 3 years, thereby enabling a detailed description of the behavioural repertoire of this widespread but barely investigated solitary African antelope species. Agonistic and submissive behaviour patterns are described, among them several hitherto un-described behaviour patterns—such as “escorting”, where territorial males guide intruders to the periphery of their territory—and “push-up position”, an extreme form of submissive behaviour. Furthermore, we report on behaviour patterns of males and females during mating as well as on behaviour patterns of parents directed towards their offspring. Again, we describe a hitherto unknown behaviour: the protection of calves by adult males, which may be a socio-positive behaviour directed towards their offspring led by kin selection.

Age-dependent mating tactics in male bushbuck (Tragelaphus scriptus)

We investigated mating tactics in three social/age classes of male bushbuck ( Tragelaphus scriptus ), i.e., adult territorial males (>5 years), young-adult non-territorial males (3-5 years) and subadult males (1-3 years). Territorial males were found to associate more frequently with females than subadult males, but young-adult males did not significantly differ from territorial males. In all three classes of males, the spatial distribution of the males relative to that of the females (i.e., their home range overlap) predicted the rate of association between males and females (Coles coefficient of association). Territorial males showed very high rates of premating behaviour compared with the other two social/age classes and frequently attempted to monopolise females; however, copulation rates did not significantly differ between adult territorial and young-adult non-territorial males. Agonistic behaviour was most frequently initiated by territorial males when approached by a young-adult male, whereas aggressive interactions between two territorial males were far less frequent. Our results indicate that two age-dependent mating tactics exist in male bushbuck, that of adult territorial males and a sneak-like tactic in young-adult males. Nevertheless, territorial males may have an advantage over non-territorial males, because they have more unhampered opportunities to monitor females via deposited excreta in localised defecation sites.

Foraging height levels and the risk of gastro-intestinal tract parasitic infections of wild ungulates in an African savannah eco-system

SummaryGrazing herbivores mainly feed at low feeding height levels, while browsers select food items above ground level. Previous studies on gastrointestinal tract (GIT) nematode parasite burdens of African ungulates have suggested that browsing species hereby minimise the risk of infection with parasites. Here, we investigated the influence of feeding height levels on the pasture larval contamination level (PCL) in a natural African savannah eco-system in Queen Elizabeth National Park, western Uganda. The prevalence and mean abundance of infectious GIT nematode larvae on the pasture were used as measures of pasture contamination. Vegetation samples were examined following standard larval isolation, concentration and counting techniques. We found the feeding height level to be significantly related to the occurrence of infectious GIT nematode larvae, and the contamination was highest at low feeding levels. There was no statistically significant seasonal variation in the prevalence or mean abundance of the contamination of pastures with nematode larvae.

Sex difference in the communicatory significance of localized defecation sites in Arabian gazelles (Gazella arabica)

Mammalian scent marking in localized defecation sites (latrines) has often been interpreted in the context of (male) territory defense. However, latrines could have different functions in males and females, especially where territorial males monopolize groups of females with stable social alliances and pronounced home range overlap. We investigated the communicatory significance of latrines in wild Arabian gazelles (Gazella arabica) and assessed the spatial distribution of latrines within home ranges. Latrine density and utilization was highest in the center of female group home ranges, and less frequent in peripheral home range sections, pointing towards communication within groups rather than towards territoriality. When considering male home ranges, latrine densities and utilization were higher in non-overlap zones, contradicting a territorial function. This pattern appears to be caused by more females than territorial males per given area establishing latrines. A subsequent survey of latrine utilization, based on camera trapping, suggests that males use latrines for territory defense: males visited latrines in overlap zones disproportionally more often than females, and successions of two males prevailed. Our study thus highlights that male territorial marking can be masked when males and females use the same marking system for different purposes.