Research Articles (Zoology and Entomology)

Permanent URI for this collectionhttp://hdl.handle.net/2263/1740

A collection containing some of the full text peer-reviewed/ refereed articles published by researchers from
the Department of Zoology and Entomology

Browse

Now showing 1 - 20 of 2548

Behavior and functional ecology of the African termite-raiding ant
Yusuf, Abdullahi Ahmed (Annual Reviews, 2026-01)
Ants and termites play important roles in tropical ecosystems, leading to an evolutionary arms race in which diverse foraging, predation, and counterpredation strategies developed. These strategies resulted in the emergence of specialized predators of termites, such as the African termite-raiding ant, Megaponera analis, which organizes coordinated raids on termites of agricultural importance belonging to the subfamily Macrotermitinae. Decades of field and laboratory studies have examined the natural history of M. analis, describing its distribution, raiding behavior, chemical ecology, task allocation, rescue and other helping behaviors, and nursing of wounds. However, the potential of M. analis for the management of termites is yet to be explored. This review synthesizes the literature on M. analis, outlines recent progress in understanding its ecology, identifies knowledge gaps, and proposes directions for future research and possible applications of the knowledge to different fields.
Subterranean mammalian societies : identity and social architecture in eusocial mole-rats
Hart, Daniel William; Jacobs, Paul Juan; Bennett, Nigel Charles (Elsevier, 2026-01)
Societies are more than groups of animals coexisting; they are structured, enduring communities defined by stable membership, shared identity and relationships that persist across generations. Among mammals, such societies are uncommon but reach their most extreme form in the eusocial African mole-rats, namely the naked mole-rat, Heterocephalus glaber, and the Damaraland mole-rat, Fukomys damarensis. Eusociality, well known from ants, bees and termites, is a social system loosely comparable to a monarchy, in which a single breeding queen and one or a few males monopolize the colony's reproduction, while other group members suppress their own reproductive potential to serve the needs of the colony. These mole-rats are among the only mammals to fully embody this system, forming long-lived, cooperative colonies with strict boundaries between colony members and outsiders. Yet their strategies for social cohesion diverge. Fukomys damarensis depends primarily on individual familiarity to maintain group identity, thereby limiting colony size. In contrast, H. glaber uses a shared colony scent and distinct colony-specific vocal dialect to support larger, scalable societies. By comparing these societal extremes, this review explores what makes societies stable, exclusive and resilient, while highlighting the gaps in our current knowledge. HIGHLIGHTS • We review eusocial African mole-rat society formation, maintenance and defence. • We compare diverging strategies of the naked and Damaraland mole-rat. • We explore what makes these societies stable, exclusive and resilient. • We also highlight gaps in the current knowledge on these two societies.
Outbreaks of a native jewel beetle, Agrilus grandis (Coleoptera: Buprestidae), on commercial black wattle, Acaciamearnsii, plantations in South Africa
Nel, Wilma Janine; Jali, Sandisiwe; Barnes, Irene; Wondafrash, Mesfin; Hurley, Brett Phillip (Entomological Society of Southern Africa, 2026-02)
In early 2024, an outbreak of an unknown wood-borer was observed in Acacia mearnsii De Wild (black wattle) compartments in the Midlands of KwaZulu-Natal, South Africa, causing symptoms of excessive resin production. Larvae uncovered beneath the bark were morphologically identified as a flathead borer, prompting urgent investigation due to the historically low impact of wood-borers on black wattle in South Africa. DNA sequencing of the COI and CytB regions of the larvae failed to yield conclusive matches, so infested logs were collected and the infesting insects reared, resulting in the emergence of three adult beetles. Morphological examination of the adults revealed them as being Agrilus grandis Gory & Laporte 1839, a native African jewel beetle. Comparison to historical specimens housed in the FABI Insect Reference Collection based at the University of Pretoria revealed a previous, unpublished outbreak of the same species in Acacia mearnsii in 1974. However, this is the first official report of A. grandis infestations on A. mearnsii in South Africa.
Vulnerabilities of parasitoid-mediated biocontrol to climate stress
Lyberger, Kelsey P.; Machekano, Honest; Khan, Md Kawsar (Elsevier, 2026-06)
Climate change threatens vital ecosystem services, including biological control mediated by parasitoids. As higher-trophic-level organisms, parasitoids, compared to their hosts, are disproportionately vulnerable to climatic stress because their survival depends on both their own physiology and that of their hosts. This review synthesizes how rising temperatures reconfigure host–parasitoid interactions, with outcomes that are system-dependent. Common disruptions include reduced parasitism success due to narrower parasitoid thermal tolerance, phenological mismatches that desynchronize life cycles, and altered overwintering activity. As these shifts can undermine both natural and artificial biological control, elevating pest outbreak risks and threatening agroecosystem stability, we discuss how mitigating them may require adapting current biocontrol strategies. HIGHLIGHTS • Parasitoids often exhibit narrower thermal windows than their hosts. • Warming differentially alters host and parasitoid development and longevity, increasing chances of phenological mismatch. • Climate change may reduce overwintering survival in parasitoids and their ability to regulate host populations. • Warming may reduce parasitism success, impacting both artificial and natural biocontrol.
Investigating the patterns of tree cover and density in relation to abiotic and biotic factors in Kruger National Park
Riccardi, Tullia; D’Ammando, Giacomo; Wilson, Lucy; Attorre, Fabio; Davies, Andrew; Farcomeni, Alessio; MacFadyen, Sandra; Strydom, Tercia; Smit, Izak P.J.; Malatesta, Luca (Wiley, 2025-11)
Across savanna ecosystems worldwide, the decline of large trees and the rapid expansion of shrubs present major conservation challenges. These trends are especially pronounced in South Africa's Kruger National Park (KNP), the country's largest protected area. To quantify their extent and identify their drivers, we conducted a spatial assessment of tree cover and density across KNP from 2011 until 2022. We then evaluated how these response variables are influenced by abiotic factors, including fire, climate, soil, and geology, and by biotic factors, such as the densities of African elephant adult male bulls and herds, including females and calves. We defined trees as land-cover elements that cast a distinct shadow and stand taller than 5 m. Using Collect Earth, an open-source software for augmented visual interpretation of high-resolution satellite imagery, we assessed tree cover and density on 4258 plots of 0.5 ha each. We recorded 27,918 trees, equivalent to an average density of 13 trees/ha. Counts in each plot were truncated to a maximum of 30 individuals. We validated our estimates of tree cover and height against independent, high-resolution airborne LiDAR measurements, which yielded an RMSE of 8.89% for trees taller than 3 m. The relative influence of selected predictors on tree cover and density was analyzed through logistic and survival regressions. Geology had the greatest influence on tree distribution, where both tree cover and density were higher on nutrient-poor granitic substrates than on nutrient-rich basalts. Tree cover and density were higher in areas with low fire frequency, close to main rivers, and with higher sand content in the soil. The mean annual rainfall showed a positive correlation with tree cover, while it had a negative correlation with the number of trees. Elephant bulls were found to be negatively correlated with both tree cover and density. In contrast, elephant herds exhibited a positive correlation with tree cover and density. This study highlights the importance of understanding the effects of multiple factors on tree distribution and aims to provide a baseline for assessing tree cover and density across KNP to support ongoing tree management strategies and contribute to future conservation priorities.
Twenty-two years of shrub encroachment and its effects on bird communities in an African savanna
Sibiya, Muzi D.; Dlamini, Wisdom M.; McCleery, Robert A.; Sirami, Clelia; Monadjem, Ara (Wiley, 2025-12)
Open terrestrial ecosystems such as savannas have been experiencing marked increases in woody cover driven by shrub encroachment. Despite this widespread pattern, understanding the consequences for faunal communities remains challenging because long-term data are often not available and other structural changes, such as changing tree cover, may confound conclusions on shrub encroachment effects. We used satellite data and surveys of bird communities spanning 22 years to assess vegetation-cover dynamics and its effects on bird communities across the savanna ecosystem of Eswatini. We employed a hierarchical multi-species occupancy model that accounted for imperfect detection to assess changes in species occurrence, richness, and community assemblages. Between 1998 and 2020, shrub cover increased from 16% to 44% and tree cover increased from 17% to 28%. Across 64 species, shrub cover tended to have greater effects on bird occupancy than tree cover, with 34 (53%) species exhibiting positive linear associations with shrub cover and 15 (23.4%) species exhibiting a non-linear response to shrubs, where occupancy peaked at < 50% shrub cover. Shrub cover generated non-linear responses across all four bird diet groups and four of the five nesting groups. Species richness increased over time, with changes in the composition of bird assemblages being driven more by changes in shrub than tree cover. With recent predictions indicating a potential increase in shrub cover that is driven by global factors, community-wide changes in bird communities may intensify. To minimize negative consequences of changes in bird communities, land managers should initiate and expand existing woody cover management regimes in southern African savannas, where shrub cover remains high.
Testing the sentinel method : live and artificial prey display contrasting patterns of predation across an urban gradient
Zeng, Yu; Yang, Haolin; Pan, Yiheng; Li, Yuxuan; Kim, Dohee; Wang, Haokun; Feng, Jing; Huang, Yuechen; Yin, Yingjie; Zhao, Hanqing; Wu, Yuyang; Barnett, Craig R.A.; Parr, Catherine Lucy; Patrick, Samantha C.; Zou, Yi; Pagani-Núñez, Emilio (Wiley, 2025-12)
Assessing changes in the intensity of biotic interactions across environmental gradients is a central issue in ecology. The sentinel method has been widely adopted to study predator–prey interactions by establishing patches of prey under different conditions that predators can attack. Sentinels, proxies for prey, are frequently worm‐shaped prey resembling caterpillars and are commonly used to assess predation by arthropod‐feeding predators, with predation measured as the rate of disappearance or evidence of predation after a certain period of exposure. While it has been suggested that artificial sentinel prey might produce divergent results from live prey, previous studies showed mixed results in the difference between these two prey types. Results are likely to vary with context, and the assessment of different prey types along urban gradients is still lacking. Here, we performed an experiment at 10 sites across a natural‐to‐urban gradient in Suzhou (East China) combining live prey and artificial prey to determine differences in predation intensity between these prey types. We released 2575 artificial prey and 3825 live prey, either separately (artificial or live prey alone) or combined, in a randomized sequence. We found a positive relationship between our index of predation and the level of urbanization using both types of prey. However, the predation rate using artificial prey was lower than with live prey and showed a different pattern with urbanization. The predation rate using live prey was higher for avian predators and lower for insect predators with increasing urbanization. Our results show that artificial and live prey can produce divergent estimates of predation intensity. Thus, while artificial prey may be used as a rapid‐screening tool, live prey could be favored in comprehensive studies to assess this fundamental ecosystem service.
Fending for thyself : honey bees from Ethiopia inflict physical damage on varroa destructor
Wanore, Walellign Wotro; Pirk, Christian Walter Werner; Yusuf, Abdullahi Ahmed; Ayalew, Workneh; Nganso, Beatrice T. (Wiley, 2025-12)
The ectoparasitic mite Varroa destructor and its associated viruses threaten the health of honey bee (Apis mellifera L.). Yet, African populations survive mite infestations without miticide treatment largely due to social immunity behaviors. However, little is known about these defense mechanisms in A. m. simensis populations from the Amhara region of Ethiopia. Therefore, this study investigated grooming and hygienic behaviors across lowland, midland, and highland areas during the wet and dry seasons in this region. Grooming behavior was quantified by measuring adult mite infestation rates, daily natural mite fall, and the proportion of mites showing physical damage per colony. Hygienic behavior was evaluated via the removal of pin-killed brood cells. Results were compared with Kenya's resistant A. m. scutellata and susceptible European hybrids in the USA. Honey bees in the Amhara region maintained low mite infestations (< 3.5 mites/100 honey bees) and exhibited higher grooming rates, ranging between 15% to 43% and inflicted more frequently damage to legs and gnathosoma comparable to Kenya's resistant honey bees. In addition to the 10 previously known damage categories inflicted on the mites by honey bees, two new mite damage combinations were identified. Their hygienic behavior was also high, ranging between 79.9% to 98.6% within 24 h and reached 98.8% to 100% after 48 h. While adult grooming and hygienic behaviors significantly varied with landscape and/or season, neither significantly correlated with mite infestation loads, suggesting these traits confer tolerance rather than resistance. Other resistance mechanisms, such as suppressed mite reproduction in worker brood cells, may further reduce colony mite infestations and should be evaluated in future studies.
Light sensitivity and diel activity rhythms in the Angoni vlei rat (Otomys angoniensis) under natural and artificial conditions
Oosthuizen, Tasha; Pillay, Neville; Oosthuizen, Maria Kathleen (Taylor and Francis, 2025-10-16)
Artificial light at night (ALAN) can disrupt daily rhythms of wildlife, yet little is known about its effects on African rodents. We investigated the diel activity rhythms of the Angoni vlei rat (Otomys angoniensis), a species with an inconclusive temporal niche. We exposed wild-caught vlei rats to three treatments: (1) standard laboratory light–dark cycle; (2) laboratory light–dark cycle with low-intensity ALAN (2 Lux); and (3) natural ambient light and temperature fluctuations. Activity was recorded via infrared sensors, and the activity rhythm was quantified using Cosinor analysis. Activity was predominantly nocturnal across all treatments. However, rhythm amplitude, MESOR and robustness were nearly three-times higher under natural conditions than in both laboratory treatments. ALAN did not significantly suppress activity, suggesting minimal masking effects (unlike strictly nocturnal animals) and possible flexibility in the temporal niche. In nature, O. angoniensis occupies dense grass habitats, and therefore, its predominantly nocturnal activity in captivity could be due to the lack of adequate cover during experiments. Moreover, the greater activity under natural conditions could be a consequence of brighter daytime light and natural temperature cycles. We suggest that although O. angoniensis displays nocturnal activity in the laboratory, it may be more diurnal in its natural habitat. Our findings demonstrate that the temporal activity of O. angoniensis is shaped by environmental context, with implications for contextualising circadian flexibility in species inhabiting human-altered landscapes.
Efficient statistical inference of turning points in animal movement data
Alharbi, Abdulmajeed F.; Blackwell, Paul G.; Alagaili, Abdulaziz; Bennett, Nigel Charles; Scantlebury, David Michael; Potts, Jonathan R. (Wiley, 2026)
Recent years have seen a proliferation of high-frequency animal movement data, often at greater than 1 Hz, allowing us to gain much greater insight into behaviour than with lower frequency data. In particular, it is becoming possible to detect the precise points at which animals are making decisions to turn, thus placing the idea that the animals move in ‘steps and turns’ onto rigorous grounding. 2. Despite this, current efforts to ascertain the points at which animals turn tend to rely on the user making pre-determined choices of certain model parameter values. Furthermore, whilst they may give good results, there is often no theory explaining why the inferred turning points are most likely to be correct, for example by maximising a likelihood function. 3. Here, we propose a theoretically grounded statistical technique to find turning points in high-frequency movement data that does not require any a priori choices of parameter values. By testing our algorithm on simulated data, we show that our technique is both fast (e.g. 3 s to parse data points) and accurate. For example, when the standard deviation of the noise is less than around radians then our algorithm correctly identifies nearly of the turning points, providing the noise is not heavily autocorrelated. Additionally, we demonstrate the effectiveness of our technique on magnetometer data from free-ranging Arabian oryx (Oryx leucoryx). 4. Overall, our work gives a fast, accurate and statistically grounded algorithm for turning point detection in high-frequency data. The resulting model of straight-line steps and turns provides a biologically meaningful summary of the animal's movement behaviour, which has potential to be used as an input to the wide range of step-and-turn techniques used in movement ecology, such as step selection analysis and hidden Markov models of behavioural states.
A systematic revision of Equatorial Guinea's bats confirms a biodiversity hotspot in Central Africa
Torrent, Laura; Garin, Inazio; Aihartza, Joxerra; Nguema Alene, Esther Abeme; Monadjem, Ara; Juste, Javier (Oxford University Press, 2025-12)
The bat fauna of Equatorial Guinea (EG), on the western edge of the Lower Guinea rainforest, a predicted African bat diversity hotspot, remained poorly documented. We collated data from literature, natural history collections and recent fieldwork to compile a comprehensive biodiversity assessment of the bats of mainland EG. This yielded 58 taxa from 29 genera and eight families: 11 species within Pteropodidae, three within Emballonuridae, two within Rhinolophidae, six within Hipposideridae, eight within Molossidae, one within Miniopteridae, five within Nycteridae, and 22 within Vespertilionidae. We report 33 new national records and three additional taxa that require further taxonomic confirmation. Notable additions include Casinycteris campomaanensis, Coleura afra, Glauconycteris superba, Hipposideros curtus and Mops petersoni. This study provides the first detailed documentation of bat diversity for mainland EG, enhancing our understanding of species richness and distributions in this biodiversity hotspot, and offering insights to guide future ecological research and conservation efforts. The bat species richness documented in our study exceeds that of any other forest site in tropical Africa with comparable size and habitat, with additional forest-dwelling species likely yet to be found. This biodiversity assessment highlights the importance of protecting bat assemblages in EG and the broader Lower Guinea rainforest region.
Keeping up with the times : the application of innovative techniques in forensic entomology
Kotze, Zanthe; Martin-Vega, Daniel (Wiley, 2025-03)
Advancements in technology have meant that there have been significant developments in the field of forensic entomology, allow researchers to develop tools to more accurately identify entomological evidence, as well as provide more accurate estimates of postmortem interval (PMI).
Low genetic diversity and regional isolation of South Africa’s inshore Bryde’s whales
Paynee, Dominique Kelsi; Vermeulen, Els; Penry, Gwenith S.; Elwen, Simon; Matthee, Conrad; Andreotti, Sara; Bloomer, Paulette (Springer, 2026-02-03)
Effective conservation of cryptic marine species depends on a sound understanding of genetic diversity, population structure and connectivity. These data allow for the delineation of conservation units and assessment of extinction risk and are especially valuable for species with fragmented distributions or suspected regional endemism. The Bryde’s whale (Balaenoptera edeni) exemplifies a challenge, being a poorly understood baleen whale species globally, with a complex of resident inshore and migratory offshore populations across temperate and sub-tropical waters. One such is the inshore population that inhabits South African coastal waters, where it is classified nationally as Vulnerable (D1) due to its small population size. This study uses a panel of 14 microsatellite markers and mitochondrial DNA control region sequences to advance our understanding of the genetic isolation and extinction risk of this population, informing the delineation of conservation units and guiding population-specific management actions. Results indicate that this population is characterized by moderate nuclear microsatellite and low mitochondrial DNA diversity and preliminarily indicate genetic differentiation between populations in the southern African region. On a global scale the findings show differentiation between broad ocean regions and the SAi while supporting the difference in evolutionary origin of SAi and SEA. These findings underscore the need for active conservation management for this isolated coastal population since they provide genetic evidence for the recognition of a discrete management unit. It is recommended that further refinement in understanding of the population’s evolutionary distinctiveness will strengthen conservation assessments, support listing decisions, and guide targeted management interventions.
Unlocking opportunities for meaningful participation of land reform beneficiaries in the wildlife economy
Shwababa, Siviwe; Child, Matthew F.; De Vos, Alta; Mneno, Naledi; Clements, Hayley S. (Elsevier, 2025-07)
Land reform is a key social justice movement across the world, typically focused on agricultural land uses. However, in many parts of the world, land reform properties exist in regions that have high biodiversity value, where options exist for integrating land reform with wildlife-based land uses to promote both conservation and socio-economic development. To effectively design and implement policies aimed at unlocking this under-explored pathway towards inclusive wildlife economies, we need information on the opportunities and barriers confronting the establishment and operation of viable wildlife enterprises on redistributed land. We conducted a survey of 19 landholders awarded land through reform in the Eastern Cape Province of South Africa. We aimed to understand the state of wildlife economy development and assess investment needs for these market entrants. Their characteristics were contrasted with data on 74 established wildlife ranches and 21 conventional livestock farms. Despite all land reform properties listing wildlife-based economic activities in their business plans and most (84 %) having wildlife, only 42 % were generating (very limited) income from their wildlife. Common barriers to upscaling revenues from wildlife were a lack of infrastructure (particularly fencing, water, accommodation) and wildlife stocks. Engagement in the wildlife economy is further hindered by lack of decision-support on viable wildlife business models and subsequent lack of access to skills development and market information. Our results show mismatches between activities that are supported by government and property business plans, and those that are context-appropriate and viable. We suggest that South Africa’s land reform programmes need to develop targeted infrastructure and skills development that consider the most appropriate business model for a given site. The barriers and opportunities outlined here could inform strategies that leverage state and private investment to more effectively create viable wildlife-based business models and achieve the dual goals of social justice and biodiversity conservation in South Africa.
Extraction of saliva, haemolymph, salivary glands, and midgut from individual ticks (Acari: Ixodidae)
Khogali, Rua Khogali Ibrahim; Getange, Dennis; Bastos, Armanda D.S.; Masiga, Daniel; Villinger, Jandouwe (MyJove Corporation, 2025-10-31)
Ticks are blood-feeding ectoparasites recognised for their ability to transmit several infectious pathogens to humans and animals. Tick-borne pathogen (TBP) surveillance generally relies on detecting pathogens in homogenates of entire ticks, including those acquired during blood feeding, which may not be transmitted by the tick. To better understand the pathogen transmission mechanism, it is essential to investigate the dissemination and concentration of TBPs in various tick tissues, which is important for elucidating transmission mechanisms in ticks and determining their vector competence. This, in turn, rests on procedures for isolating saliva, haemolymph, salivary glands, and the midgut of individual ticks in order to examine the location of TBPs within these tissues and fluids. In this study, we describe a protocol for tick tissue collection, including a novel procedure for the collection of haemolymph. The results confirm that Rickettsia africae occurs at higher levels in the haemolymph of Amblyomma gemma, affirming the likely role of this tick species as a competent vector for R. africae. In contrast, Hyalomma dromedarii exhibited high rates of R. africae in the midgut, but the bacterium was absent in the haemolymph. The presence of TBPs in the haemolymph is therefore a valuable indicator of vector competence, and rests on the availability of a method that ensures ease of collection.
Systematics of African rough-scaled lizards, with description of two new species from eastern Angola (Squamata: Lacertidae: Ichnotropis Peters, 1854)
Conradie, Werner; Keates, Chad; Greenbaum, Eli; Lobon-Rovira, Javier; Tolley, Krystal A.; Benito, Max; Pinto, Pedro Vaz; Van Breda, Reuben V.; Verburgt, Luke (Pensoft Publishers, 2025-11)
Ichnotropis is a genus of medium-sized lacertids endemic to sub-Saharan Africa, characterised by rough head shields. The genus currently comprises six nominal species distributed across much of southern, central, and eastern Africa. Some species are apparently active at only certain times of the year, resulting in limited specimen collections and severely hampering research. This scarcity of material has historically made comprehensive systematic reviews of the genus difficult and has led to the description of numerous regional morphological variants as distinct species or subspecies. Material collected in recent years has enabled us to provide a new phylogenetic hypothesis of Ichnotropis using two mitochondrial genes (16S and ND4) and two nuclear genes (c-mos and RAG-1). Our phylogenetic dataset includes 56 individuals representing five of the six currently recognised species (excluding I. chapini). Additionally, the broad geographical sampling of the widespread I. capensis group has allowed us to explore the taxonomic status of several species and subspecies within the group. As a result, we demonstrate the monophyly of Ichnotropis in relation to other African lacertids and present the most comprehensive phylogeny of the genus to date. We also provide the first phylogenetic placements for I. tanganicana and I. grandiceps, which allows us to validate their taxonomic statuses. Furthermore, we recovered a new cryptic species closely related to I. grandiceps, and identified several well-supported clades within the I. capensis group, all corroborated by multi-locus species delimitation analyses. One of these clades is described herein as a new species, while the remaining taxa of interest are discussed and highlighted for future investigation. Based on our findings, we recommend the following taxonomic revisions: Ichnotropis longipes and I. macrolepidota should remain synonyms of I. capensis; I. bivittata pallida and I. capensis nigrescens are treated as a junior synonyms of I. bivittata; and I. overlaeti is considered a junior synonym of I. tanganicana. Although we could not determine the phylogenetic placement of I. chapini due to the lack of genetic material, its head morphology and scalation support its reassignment to the I. bivittata group. Thus, it is retained as a valid species pending the availability of new material for further taxonomic actions. In conclusion, this study resolves several long-standing taxonomic issues within one of Africa’s most understudied lacertid genera and lays a solid foundation for future research on the genus Ichnotropis.
Multi-locus sequence analysis of Anaplasma in the common warthog (Phacochoerus africanus) from South Africa
Rea, Keaton; Buss, Peter Erik; Bastos, Armanda D.S. (Elsevier, 2025-12)
The prevalence and diversity of Anaplasma in common warthog (Phacochoerus africanus) was investigated using a multi-locus sequence analysis (MLSA) approach targeting the 16S rRNA, citrate synthase (gltA) and heat-shock operon (groESL) genes. PCR screening of 100 warthog samples from the Kruger National Park in South Africa with eight published assays identified 50 positive animals, all of which were initially identified with the 16S rRNA assay. In contrast, the gltA and six groESL assays recovered PCR-positivity rates of 2 % and 0 %-4 %, respectively. As optimisation did not improve Anaplasma detection rates, an alternative groESL assay targeting a 923 bp region was designed. This new assay detected 45 positive animals, all of which were positive with the 16S rRNA assay. Nucleotide sequencing of the three MLSA gene targets confirmed that 50 % (50/100) of warthogs were Anaplasma-positive. Juvenile warthogs displayed a significantly higher infection rate (15/18; 83.3 %) than adults (35/82; 42,68 %). Phylogenetic analyses of individual and concatenated gene datasets confirmed that the Anaplasma species in warthogs is closely related to the species detected in Ornithodoros soft ticks from Zambia. This, together with the high levels of nucleotide sequence identity (≥98.97 %), suggests the likely existence of a host-restricted cycle involving warthogs and the soft ticks that inhabit their burrows. Based on the distinctiveness and monophyly of the Anaplasma species in warthogs and Ornithodoros soft ticks, confirmed through genetic characterisation of three gene regions, we propose that Candidatus status be assigned and suggest “Candidatus Anaplasma ornithodorii”. HIGHLIGHTS • Overall sequence-confirmed Anaplasma prevalence of 50 % in warthogs. • Three gene regions (16S rRNA, gltA and groEL) were characterised. • Anaplasma species in warthogs matches species detected in Ornithodoros soft ticks.
Reproductive females of a cooperatively breeding rodent are in better body condition when living in large groups
Finn, K.T.; Janse van Vuuren, Andries Koch; Suess, Tobias; Hart, Daniel William; Bennett, Nigel Charles; Zottl, M. (Wiley, 2025-07)
Cooperation and group living have been suggested to facilitate survival in varying environments and under challenging conditions. However, group living may also be associated with costs, particularly in species where individuals within groups may compete for limited resources. The costs and benefits of cooperative group living on cooperatively breeding mammals in varying environments remain unclear. Here, we use data collected from wild, cooperatively breeding Natal mole-rats (Cryptomys hottentotus natalensis) inhabiting a seasonally varying environment to assess whether body condition changes between seasons and whether these changes are contingent upon group size. We demonstrate that the body condition of reproductive females improved with increasing helper number during both the benign summer and the harsher winter seasons. However, the body condition of other group members showed little dependency on group size or season. Only when including one extremely large group did the body condition of non-breeders weakly, albeit significantly, change depending on group size and seasonality. These results suggest that larger group sizes may yield some benefits for non-breeding group members during winter and may invoke some costs during summer. Group living in Natal mole-rats is likely promoted by a combination of collective foraging, thermoregulatory benefits, and potentially some indirect fitness benefits through improved body condition of the breeding female.
Fertility up in flames : reduced fertility indices as a consequence of a simulated heatwave on small African mammals
Jacobs, Paul Juan; Bennett, Nigel Charles; Du Plessis, L.; Hart, Daniel William (Wiley, 2025-03)
With the increasing frequency and intensity of heatwaves due to climate change, the survival and reproductive success of mammals could be under significant threat. However, the specific effects of these environmental stressors on mammalian reproductive fitness remain insufficiently explored. This study investigates the impact of a simulated heatwave on male fertility indices in two African rodent species: the mesic four-striped field mouse (Rhabdomys dilectus) and the Namaqua rock mouse (Micaelamys namaquensis) during the breeding season. We measured key indicators of male fertility, including testes mass, testes volume, seminiferous tubule diameter, the presence of sperm, and plasma testosterone levels. Our findings reveal that both species experienced significant effects on male fertility indices, with the smaller R. dilectus showing a decline in all fertility indices following a simulated heatwave. These results suggest that the projected increase in heatwave events may compromise the reproductive success of small mammals, potentially leading to population declines. Finally, this study highlights the need for focused studies on the effect of heatwaves on long-term reproductive success in both males and females.
Examining alterations in fGCM concentrations post-defaecation across three animal feeding classes (ruminants, hindgut fermenters and carnivores)
Osburn, Kayla Rae; Crossey, Bruce Gareth; Majelantle, Tshepiso Lesedi; Ganswindt, Andre (Wiley, 2025-05)
Quantification of faecal glucocorticoid metabolites (fGCMs) is a popular non-invasive technique for monitoring wildlife's response to stressors, demanding an understanding of the stability of fGCM concentrations post-defaecation to ensure comparability of determined fGCM values across samples. To provide species-specific recommendations for the duration within which sampling can take place, we measured the rate at which the fGCM concentrations of nine different species changed throughout a 7-day period post-defaecation. In this study, we explored the temporal dynamics of fGCM concentrations in nine species across three feeding classes (ruminants, hindgut fermenters and carnivores): impala (Aepyceros melampus), giraffe (Giraffa camelopardalis), blue wildebeest (Connochaetes taurinus), plains zebra (Equus quagga), African elephant (Loxodonta africana), white rhino (Ceratotherium simum), cheetah (Acinonyx jubatus), spotted hyena (Crocuta crocuta) and leopard (Panthera pardus). Utilizing enzyme immunoassays already established for each of the focal species, we identified broader feeding class-specific patterns. All herbivores exhibited a significant decrease in fGCM concentrations over time, starting from 6 h (impala) to 48 h (giraffe, blue wildebeest, white rhino and African elephant) post-defaecation. For carnivores, concentrations remained fairly comparable for 12–24 h, after which fGCM concentrations either decreased (spotted hyena), increased (leopard) or remained stable (cheetah), with notable variation in triplicate concentrations (cheetah and leopard). These findings offer insights into scheduling faecal sampling for endocrine monitoring, particularly from free-roaming wildlife, to ensure comparability of determined hormone metabolite concentrations. Furthermore, the species-specific variation in fGCM concentration post-defaecation demonstrated in this study underlines the necessity to investigate every new species to ensure accurate and comparable results. Future studies ought to investigate how the mass of collected material, sex and drying methodologies affect the measurement of fGCMs post-defaecation.

Browse

Recent Submissions