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

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Dietary modulation of gut microbiota and functional enzymes in savannah honey bees (Apis mellifera scutellata Lepeletier)
(Springer, 2025-10) Khumalo, Nolwandle N.; Obi, Linda U.; Yusuf, Abdullahi Ahmed; Adeleke, Rasheed A.
Honey bees gather pollen from flowering plants, using it as a vital protein source and, in turn, acquire pollen-associated microbes that interact with their existing gut microbiota. Despite their ecological importance, limited information exists regarding the gut microbiota of African savannah honey bees (Apis mellifera scutellata Lepeletier) and how diet and its associated microbial community influence this crucial internal ecosystem. This study aimed to investigate the differences in gut microbiota between wild honey bees collected during the flowering season and microbially depleted honey bees reared under semi-sterile conditions and fed various protein diets. To achieve this, freshly hatched worker bees were maintained in hoarding cages and assigned one of four protein diets: fresh sunflower pollen, casein, sterilised casein, or sterilised pollen. High-throughput DNA metabarcoding was then employed to compare the microbial composition of the honey bee gut across these groups. Our findings revealed that the gut of microbially depleted honey bees exhibited higher species diversity and richness. Conversely, the non-core gut microbial community predominated in wild bees and those fed the different protein diets. Specifically, Commensalibacter, Bartonella, and Bifidobacterium were the most dominant bacterial genera across all treatments. Interestingly, Gilliamella, a common core gut bacterium, was undetected, while Apibacter was exclusively found in wild honey bees. Furthermore, pollen-associated microbes such as Devosia and Pedobacter were identified solely in the gut of honey bees fed a pollen diet. Functional predictions of the gut microbial community also indicated the presence of key enzymes such as β-glucosidase, β-galactosidase, pyruvate dehydrogenase and phosphoglycerate mutase, which are crucial for enhancing nutrient absorption, digestion, and carbohydrate metabolism. These results underscore the intricate relationship between honey bees, microbes, and plants, offering valuable insights into how diet and its associated microbial communities could shape the gut microbiota of African honey bees. KEY POINTS • The non-core gut microbiota dominates the African savannah honey bee • The type of diet influenced the microbial diversity and community abundance in the honey bee gut • Key enzymes involved in digestion, nutrition absorption, and carbohydrate metabolism were enhanced in the gut • Pollen-associated microbes found in the diet present potential avenues for probiotic development to improve honey bee health
Spatiotemporal variation of small hive beetle infestation levels in honeybee host colonies
(Springer, 2025-09) Palonen, Aura; Papach, Anna; Muturi, Michael N.K.; Weinstein Teixeira, Erica; Williams, Geoffrey R.; Jacobsen, Rachel; Evans, Jay D.; Posada-Florez, Francisco J.; Pirk, Christian Walter Werner; Lattorff, H. Michael G.; Lawrence, Akinwande K.; Oluseyi, Murele O.; Spooner-Hart, Robert; House, Clarissa M.; Federico, Giovanni; Formato, Giovanni; Neumann, Peter
High infestation levels of small hive beetle (SHB), Aethina tumida, can cause more damage to honeybee, Apis mellifera, host colonies. However, the spatiotemporal variation of SHB infestations is poorly understood. Here, we show that SHB infestations can be equally high in native and invasive ranges, suggesting that differences between host populations are the key criterion for damage. The data reveal that spatial variation within locations was not correlated with migratory beekeeping, SHB management strategies, nor the number of colonies at an apiary. Despite no annual changes in SHB infestations, the data confirm seasonal variation in infestations in two locations probably due to environmental factors affecting SHB. Infestations are lower in Italy than elsewhere, possibly due to strongly implemented management strategies. It is apparent that our understanding of varying SHB infestations is still limited. This suggests that further efforts are required to elucidate our knowledge of this important host-parasite system.
Underrepresentation of bats in Africa's protected areas
(Wiley, 2025) Montauban, Cecilia; Budinski, Ivana; Webala, Paul W.; Laverty, Theresa M.; Tanshi, Iroro; Torrent, Laura; Bakwo-Fils, Eric; Taylor, Peter J.; Kane, Adam; Monadjem, Ara
Biodiversity is severely threatened globally, with habitat loss and other human pressures accelerating species extinctions. Protected areas (PAs) are a critical conservation tool; however, their effectiveness in safeguarding many taxa, such as bats, remains unclear. Using georeferenced occurrence records and species distribution models (SDMs) for 263 sub-Saharan African bat species, we evaluated the coverage of bats in 7875 terrestrial PAs. Eighty-nine percent of bat species were recorded in at least 1 PA, yet 28 species, including 5 threatened and 15 data deficient species, were absent from all PAs. Species with large extents of occurrence were represented in more PAs, and fruit bats occupied significantly more PAs than clutter, edge, or open-air insectivorous foragers. The SDMs revealed high species richness in some undersurveyed areas, particularly in West and Central Africa and the Albertine Rift, emphasizing the need for targeted surveys. Our findings underscore critical data deficiencies related to bat conservation and stress the urgency of integrating bats into broader conservation planning. More surveys, enhanced data-sharing, and tailored conservation strategies are needed to improve bat representation in PAs and safeguard their ecological roles in Africa's biodiverse landscapes.
Early detection of Phytophthora root rot in Eucalyptus using hyperspectral reflectance and machine learning
(Elsevier, 2025-10) Esterhuizen, Hendrik J.; Slippers, Bernard; Bosman, Anna Sergeevna; Roux, Jolanda; Jones, Wayne; Bose, Tanay; Hammerbacher, Almuth; tanay.bose@fabi.up.ac.za
The rising prevalence of Phytophthora diseases in forests highlights the need for rapid, non-invasive detection methods. Early-stage root infections are difficult to detect due to the absence of visible above-ground symptoms, while current diagnostics remain slow and invasive. This study investigated whether hyperspectral leaf reflectance could detect root rot caused by Phytophthora alticola in Eucalyptus benthamii. Nineteen commercially planted families were inoculated, and leaf spectra were collected using an ASD FieldSpec 4 sensor. A machine learning pipeline was developed to identify diagnostic spectral signals. Key wavelengths were identified using permutation importance, a genetic algorithm, and self-attention network (SAN) scores. Spectral signals linked to root rot revealed that infection was correlated with leaf pigment accumulation and moisture stress. Three algorithms, random forest (RF), support vector machine (SVM), and SAN, were trained on hyperspectral data to predict P. alticola infection. The SAN achieved 97 % accuracy on a reduced dataset, which included the diagnostic wavelengths from the feature selection step, surpassing the RF (96 %) and SVM (94 %) models. This study demonstrates hyperspectral sensing as an effective tool for detecting Phytophthora root rot using spectra from the foliage and highlights the application of advanced machine learning techniques for plant disease classification. HIGHLIGHTS • Hyperspectral sensing detects Phytophthora root rot before symptoms appear. • SAN model achieved 97 % accuracy using selected wavelengths from leaf spectra. • Key wavelengths correlated with pigment shifts and moisture stress in leaves. • Machine learning identified spectral markers for early disease detection. • Vegetation indices NDNI and MSI are strongly linked to infection status.
Increases in humidity will intensify lethal hyperthermia risk for birds occupying humid lowlands
(Oxford University Press, 2025-06) Coulson, Bianca; Freeman, Marc Trevor; Conradie, Shannon Rose; McKechnie, Andrew E.; andrew.mckechnie@up.ac.za
Please read abstract in the article. LAY SUMMARY Many tropical birds will experience hotter and more humid wet-season conditions in future. In an African forest frugivore, we found the maximum tolerable wet-bulb temperature is 31.7°C and risks of lethal hyperthermia will increase substantially by 2100. These findings reveal a pervasive but understudied threat facing birds inhabiting humid lowlands.
Neonatal antipredator tactics shape female movement patterns in large herbivores
(Nature Research, 2025-01) Atmeh, Kamal; Bonenfant, Christophe; Gaillard, Jean-Michel; Garel, Mathieu; Hewison, A.J. Mark; Marchand, Pascal; Morellet, Nicolas; Anderwald, Pia; Buuveibaatar, Bayarbaatar; Beck, Jeffrey L.; Becker, Matthew S.; Van Beest, Floris M.; Berg, Jodi; Bergvall, Ulrika A.; Boone, Randall B.; Boyce, Mark S.; Chamaillé-Jammes, Simon; Chaval, Yannick; Buyanaa, Chimeddorj; Christianson, David; Ciuti, Simone; Cote, Steeve D.; Diefenbach, Duane R.; Droge, Egil; Du Toit, Johan T.; Dwinnell, Samantha; Fennessy, Julian; Filli, Flurin; Fortin, Daniel; Hart, Emma E.; Hayes, Matthew; Hebblewhite, Mark; Heim, Morten; Herfindal, Ivar; Heurich, Marco; Von Hoermann, Christian; Huggler, Katey; Jackson, Craig; Jakes, Andrew F.; Jones, Paul F.; Kaczensky, Petra; Kauffman, Matthew; Kjellander, Petter; LaSharr, Tayler; Loe, Leif Egil; May, Roel; McLoughlin, Philip; Meisingset, Erling L.; Merrill, Evelyn; Monteith, Kevin L.; Mueller, Thomas; Mysterud, Atle; Nandintsetseg, Dejid; Olson, Kirk; Payne, John; Pearson, Scott; Pedersen, Ashild Onvik; Ranglack, Dustin; Reinking, Adele K.; Rempfler, Thomas; Rice, Clifford G.; Roskaft, Eivin; Saether, Bernt-Erik; Said, Sonia; Santacreu, Hugo; Schmidt, Niels Martin; Smit, Daan; Stabach, Jared A.; St-Laurent, Martin-Hugues; Taillon, Joelle; Walter, W. David; White, Kevin; Peron, Guillaume; Loison, Anne
Caring for newborn offspring hampers resource acquisition of mammalian females, curbing their ability to meet the high energy expenditure of early lactation. Newborns are particularly vulnerable, and, among the large herbivores, ungulates have evolved a continuum of neonatal antipredator tactics, ranging from immobile hider (such as roe deer fawns or impala calves) to highly mobile follower offspring (such as reindeer calves or chamois kids). How these tactics constrain female movements around parturition is unknown, particularly within the current context of increasing habitat fragmentation and earlier plant phenology caused by global warming. Here, using a comparative analysis across 54 populations of 23 species of large herbivores from 5 ungulate families (Bovidae, Cervidae, Equidae, Antilocapridae and Giraffidae), we show that mothers adjust their movements to variation in resource productivity and heterogeneity according to their offspring’s neonatal tactic. Mothers with hider offspring are unable to exploit environments where the variability of resources occurs at a broad scale, which might alter resource allocation compared with mothers with follower offspring. Our findings reveal that the overlooked neonatal tactic plays a key role for predicting how species are coping with environmental variation.
Interactions among nutrients govern the global grassland biomass-precipitation relationship
(National Academy of Sciences, 2025-04-11) Fay, Philip A.; Gherardi, Laureano A.; Yahdjian, Laura; Adler, Peter B.; Bakker, Jonathan D.; Bharath, Siddharth; Borer, Elizabeth T.; Harpole, W. Stanley; Hersch-Green, Erika; Huxman, Travis E.; Macdougall, Andrew S.; Risch, Anita C.; Seabloom, Eric W.; Bagchi, Sumanta; Barrio, Isabel C.; Biederman, Lori; Buckley, Yvonne M.; Bugalho, Miguel N.; Caldeira, Maria C.; Catford, Jane A.; Chen, Qingqing; Cleland, Elsa E.; Collins, Scott L.; Daleo, Pedro; Dickman, Christopher R.; Donohue, Ian; Dupre, Mary E.; Eisenhauer, Nico; Eskelinen, Anu; Hagenah, Nicole; Hautier, Yann; Heckman, Robert W.; Jonsdottir, Ingibjoerg S.; Knops, Johannes M.H.; Laungani, Ramesh; Martina, Jason P.; Mcculley, Rebecca L.; Morgan, John W.; Venterink, Harry Olde; Peri, Pablo L.; Power, Sally A.; Raynaud, Xavier; Ren, Zhengwei; Roscher, Christiane; Smith, Melinda D.; Spohn, Marie; Stevens, Carly J.; Tedder, Michelle J.; Virtanen, Risto; Wardle, Glenda M.; Wheeler, George R.
Ecosystems are experiencing changing global patterns of mean annual precipitation (MAP) and enrichment with multiple nutrients that potentially colimit plant biomass production. In grasslands, mean aboveground plant biomass is closely related to MAP, but how this relationship changes after enrichment with multiple nutrients remains unclear. We hypothesized the global biomass–MAP relationship becomes steeper with an increasing number of added nutrients, with increases in steepness corresponding to the form of interaction among added nutrients and with increased mediation by changes in plant community diversity. We measured aboveground plant biomass production and species diversity in 71 grasslands on six continents representing the global span of grassland MAP, diversity, management, and soils. We fertilized all sites with nitrogen, phosphorus, and potassium with micronutrients in all combinations to identify which nutrients limited biomass at each site. As hypothesized, fertilizing with one, two, or three nutrients progressively steepened the global biomass–MAP relationship. The magnitude of the increase in steepness corresponded to whether sites were not limited by nitrogen or phosphorus, were limited by either one, or were colimited by both in additive, or synergistic forms. Unexpectedly, we found only weak evidence for mediation of biomass–MAP relationships by plant community diversity because relationships of species richness, evenness, and beta diversity to MAP and to biomass were weak or opposing. Site-level properties including baseline biomass production, soils, and management explained little variation in biomass–MAP relationships. These findings reveal multiple nutrient colimitation as a defining feature of the global grassland biomass–MAP relationship. SIGNIFICANCE Understanding how multiple interacting nutrients regulate the global relationship between mean annual precipitation and aboveground biomass is crucial for forecasting how ecosystem functioning will be altered by ongoing global changes. We fertilized with nitrogen, phosphorus, and potassium plus micronutrients in all combinations in 71 grasslands representing a global precipitation gradient. The grassland biomass–precipitation relationship became steeper with an increasing number of added nutrients. Increases in steepness corresponded to the form of interaction among added nitrogen and phosphorus. We found weak evidence that variation in plant species diversity mediated changes in the biomass–precipitation relationship. Multiple nutrient colimitation, particularly by nitrogen and phosphorus, is a defining feature of grassland biomass–precipitation relationships, and crucial to predicting grassland responses to global change.
A heat-sensitive songbird's risk of lethal hyperthermia increases with humidity
(Royal Society, 2025-10) Liddle, Nazley; Freeman, Marc Trevor; Cunningham, Susan J.; Conradie, Shannon Rose; McKechnie, Andrew E.
Please read abstract in the article.
Climate-driven potential for tularemia in East Africa : skill testing and ecological consistency of a transferred risk model
(Elsevier, 2025-11) Agboka , Komi Mensah; Ng´anga, Allan Muohi; Sokame, Bonoukpoe Mawuko; Baleba, Steve B.S.; Landmann , Tobias; Abdel-Rahman, Elfatih M.; Tanga , Chrysantus M.; Diallo, Souleymane
Tularemia, a neglected zoonosis, remains underreported in Africa despite growing concern over its climate-driven expansion. This study aims to quantify the specific contribution of climate to tularemia risk using a climate attribution framework. We trained a Least Squares Dummy Variable (LSDV) fixed-effects panel model on United States (U.S.) county-level tularemia incidence data from 2011–2020 (n = 500, R² = 0.90), incorporating only climatic predictors: cumulative temperature, cumulative precipitation, and their respective variabilities. The climate-only model explained 86% of variance in the training data, demonstrating strong climate influence on tularemia disease dynamics. We then applied the model to East Africa, using environmental similarity analysis to assess transferability. Results show moderate-to-high climatic analogues in northern Kenya, eastern Uganda, and South Sudan. Between 2017 and 2020, predicted tularemia suitability increased by a median of +0.18 compared to the 2012–2015 baseline, particularly in arid and semi-arid zones. Low interannual variability suggests persistent climatic suitability. A thermal plausibility test showed strong agreement (r = 0.82) between predicted risk and the Gaussian thermal profile of Francisella tularensis. Our findings suggest that climate alone can spatially explain tularemia risk across Africa’s drylands. This method provides a transferable framework for early warning in data-poor regions and supports anticipatory surveillance in the context of climate change.
Honey bee colony losses and causes during the active beekeeping season 2022/2023 in nine Sub-Saharan African countries
(Public Library of Science, 2025-05) Nganso, Beatrice T.; Ayalew, Workneh; Wubie, Abebe J.; Assefa, Freweini; Belayhun, Lulseged; Ndungu, Nelly N.; Toroitich, Daniel; Otieno-Ayayo, Z. Ngalo; Wambua, Mbatha B.; Oyieyo, Yudah O.; Elie, Ntirenganya; Sikirou, Rachidatou; Idrissou, Souradji B.; Mwiza, Willy; Turner, S.; Bobadoye, Bridget O.; Fameni, Sidonie T.; Gaboe, Sayemie; Agbodzavu, Mawufe K.; Mafwila, Patrick; Taboue, Geraud C. Tasse; Emily, Kimathi; Henri, Tonnang Z.E.; Niassy, Saliou; Fonkou, Simplice N.; Pirk, Christian Walter Werner; Gray, Alison; Brodschneider, Robert; Soroker, Victoria; Subramanian, Sevgan
This study reports for the first-time a multi-country survey of managed honey bee colony loss rates and associated risk factors during the active beekeeping season 2022/2023 in nine Sub-Saharan African countries, namely Kenya, Ethiopia, Rwanda, Uganda, Benin, Liberia, Nigeria, Cameroon and Democratic Republic of the Congo. It also evaluates the sustainability of bee swarm catches as a primary source for expanding apiary size by African beekeepers. In this survey, the 1,786 interviewed beekeepers across these countries collectively managing 41,761 colonies registered an overall loss rate of 21.3%, which varied significantly among countries (from 9.7 to 45.3%) and hive types (from 10.6% in hives with movable frames to 17.9% in frameless hives). The perceived causes of losses in order of significance were issues beyond the beekeeper’s control (mostly theft, drought, and bushfire), absconding and pests (mostly wax moth, small and large hive beetles, ants and Varroa destructor mite), but this pattern varied greatly across countries. Among the management practices and characteristics, migratory beekeepers and professional beekeepers experienced lower losses than beekeepers practicing stationary beekeeping and semi-professionals and hobby beekeepers, respectively. Insights into the number of bee swarms caught revealed a significant decrease in swarm availability over the past three years in Kenya, while some regions in Ethiopia showed the opposite trend, requiring further investigation. Overall, this comprehensive survey highlights the complexities and challenges faced by beekeepers in Sub-Saharan Africa, underscoring the need for targeted interventions and sustained research to support the resilience and growth of the apicultural sector.
Mathematical assessment of co-dynamics of deformed wing virus variants A and B infections in honeybees
(Elsevier, 2026-03) Hussaini, Nafiu N.; Yusuf, Abdullahi Ahmed; Ishaku, Adamu; abdullahi.yusuf@up.ac.za
This study presents a mathematical model to assess the co-dynamics of infections with Deformed Wing Virus (DWV) Variants A and B within a honeybee hive. The model is analyzed via submodels, DWV A only and DWV B only. Our qualitative analysis results demonstrate that the disease-free equilibrium of each submodel is locally asymptotically stable when the corresponding reproduction number is below one. In addition, the submodels exhibit backward bifurcation. A numerical simulation shows that breeding bees for resistance reduces the number of infected brood and adults. The simulation further suggests that enhancing the efficiency of breeding bees for hygienic and grooming behavior in bees could be an effective strategy for controlling the spread of both DWV variants and mite populations. The sensitivity analysis results show that the most important parameters that contribute to the generation of more DWV infections are the transmission rate of DWV-B, the rate of maturation to infected adult bees, and the egg-laying rate. Furthermore, the uncertainty analysis result highlights that focusing on interventions like breeding bees for resistance, hygienic, and grooming behavior could lead to a relatively lower reproduction number. Finally, the result obtained from cost-effectiveness analysis suggests that implementing all interventions concurrently (the universal strategy) is the most cost-effective when resources are available. Otherwise, breeding bees for hygiene and grooming behavior is the most cost-effective strategy. However, the choice of which strategy to implement depends on policymakers’ budget constraints. HIGHLIGHTS • Deformed Wing Virus A and B co-dynamics model is proposed and analyzed. • Intervention strategies: breeding for resistance, hygienic and grooming behavior are incorporated in the model. • Numerical simulation was used to assess the impact of the intervention strategies. • Concurrent implementation of all the aforementioned strategies is the most cost effective strategy if the resources are available.
Chemically mediated multitrophic interactions and their role in crop protection
(Elsevier, 2026-02) Torto, Baldwyn; Kihika-Opanda, Ruth; Khamis, Fathiya Mbarak
Agricultural production is primarily constrained by biotic stresses, with insect pests being the most significant contributors. Effective pest management is essential for sustainable crop protection and relies on understanding how plants interact with pests (herbivores), their natural enemies (predators and parasitoids), other plants, and beneficial organisms such as pollinators. These interactions, which are also frequently influenced by microorganisms, collectively referred to as multitrophic interactions, play a crucial role in shaping agroecosystems. Recent research highlights that in agricultural systems, multitrophic interactions are primarily mediated by volatile organic compounds and other specialized metabolites through microbial activity. A deeper understanding of these chemically mediated mechanisms in pest, natural enemy, and pollinator attraction/repellence, and plant defense priming, offers new opportunities for developing ecologically sustainable pest management strategies. This review aims to synthesize emerging evidence on the role of plant- and microbial-derived specialized metabolites in mediating multitrophic interactions and potential applications for crop protection. It also identifies knowledge gaps and explores how recent advances are shaping the development of innovative crop protection technologies. HIGHLIGHTS • Multitrophic interactions play a key role in agricultural systems and food productivity. • Plant volatiles and secondary metabolites contribute to shaping multitrophic interactions. • Microbial-mediated specialized metabolites also contribute to shaping multitrophic interactions. • Diverse chemical classes influence multitrophic interactions. • Understanding multitrophic interactions facilitates development of innovative crop protection technologies.
Managing African armyworm outbreaks in sub-Saharan Africa : current strategies and future directions
(MDPI, 2025-06) Kinyanjui, Grace; Mawcha, Kahsay Tadesse; Malinga, Lawrence Nkosikhona; Soobramoney, Kaitlyn; Nethononda, Phophi; Assefa, Yoseph; Okonkwo, Chibuzor Onyinye; Ndolo, Dennis; phophi.nethononda@fabi.up.ac.za
The African armyworm Spodoptera exempta (Lepidoptera: Noctuidae) is a significant pest that affects cereal crops and pasture grasses in sub-Saharan Africa. This migratory pest causes extensive defoliation, which can result in significant yield losses, particularly in maize. This review focuses on the recent outbreaks of the African armyworm and identifies key factors contributing to its success across sub-Saharan Africa. Understanding these factors is essential for developing effective and sustainable pest management strategies. This review emphasizes the importance of innovative technologies and data-driven approaches in managing pest outbreaks and underscores the need to implement technology-enabled integrated pest management (IPM) strategies to control the African armyworm effectively. SIMPLE SUMMARY The African armyworm is a destructive, migratory pest that threatens cereal crops and pasture grasses in sub-Saharan Africa, with recent outbreaks resulting in significant agricultural and economic losses. This review addresses the urgent need for improved management strategies by examining the drivers of frequent outbreaks, including climate change, the pest’s biological traits, and gaps in current control practices. This paper aims to evaluate existing surveillance and control methods—such as chemical, biological, and cultural approaches—and to explore innovative technologies, including predictive modeling, artificial intelligence, Bt maize technology, molecular biology, and nanotechnology. This study finds that, while traditional methods offer some control, their limitations necessitate integrated, technology-enabled pest management solutions. It concludes that adopting holistic, regionally coordinated strategies that incorporate farmer education, advanced tools, and updated policy frameworks will significantly improve outbreak response and mitigation. These findings are valuable to society as they provide a roadmap for sustainable pest control, helping to safeguard food security, support farmer livelihoods, and enhance agricultural resilience in the face of escalating climate and pest pressures.
Know where you go : infestation dynamics and potential distribution of two bed bug species (Hemiptera: Cimicidae) in Africa
(MDPI, 2025-04) Mbuta, Dennis M.; Sokame, Bonoukpoe M.; Khamis, Fathiya Mbarak; Akutse, Komivi S.
Bed bugs (Hemiptera: Cimicidae) are blood-feeding insects closely linked with humans and animals, causing discomfort, and posing potential threats as disease vectors. This study focuses on Cimex lectularius (common bed bug) and Cimex hemipterus (tropical bed bug), the two key species identified in Africa. Cimex lectularius infests human habitats, while C. hemipterus, more common in Africa, infests diverse habitats, including bat colonies. In our study, we investigated the infestation dynamics and distribution of bed bugs in Africa, when considering climate, habitat, and host availability using system dynamics and ecological niche modelling techniques. System dynamics modelling analyses in Kenya revealed varied infestation dynamics, with Mombasa having high C. lectularius prevalence, Nairobi having lower coexistence, and Makueni/Bomet C. hemipterus showing dominance. Across Africa, C. hemipterus prevails, especially in central and coastal areas, while C. lectularius has lower suitability, with isolated high-suitability zones. Both species coexist in central/southern Africa, parts of the east, and coastal areas in septentrional/west Africa. The Sahara’s extreme conditions challenge both bed bug species’ survival, emphasizing climate’s role in their infestation and distribution dynamics. Insights into bed bug ecology in Africa underscore the need for comprehensive pest management and public health strategies in the continent. SIMPLE SUMMARY This study explores the dynamics of bed bug infestations in Africa, focusing on two species: the common (Cimex lectularius) and the tropical (Cimex hemipterus) bed bugs. These bugs, known for feeding on blood, are not only a nuisance but can potentially transmit diseases. The research utilized system dynamics modeling for infestation and ecological niche modeling to analyze their potential distribution across different climates and habitats and their host availabilities in Africa. The findings revealed varied infestation patterns in Kenya, with a high prevalence of C. lectularius in Mombasa and dominance of C. hemipterus in regions like Makueni and Bomet. This study maps the potential spread of these species across Africa, highlighting areas with high coexistence risks. This research is crucial as a prerequisite for developing effective pest management strategies and public health measures to combat bed bug infestations, thus safeguarding local and regional food supplies and overall human health.
Understanding the genetics of sex determination in insects and its relevance to genetic pest management
(Wiley, 2025-06) Ashmore, Jade Sabrina; Slippers, Bernard; Duong, Tuan A.; Dittrich-Schroder, Gudrun; gudrun.dittrich@fabi.up.ac.za
Sex determination pathways regulate male and female-specific development and differentiation and offer potential targets for genetic pest management methods. Insect sex determination pathways are comprised of primary signals, relay genes and terminal genes. Primary signals of coleopteran, dipteran, hymenopteran and lepidopteran species are highly diverse and regulate the sex-specific splicing of relay genes based on the primary signal dosage, amino acid composition or the interaction with paternally inherited genes. In coleopterans, hymenopterans and some dipterans, relay genes are Transformer orthologs from the serine-arginine protein family that regulate sex-specific splicing of the terminal genes. Alternative genes regulate the splicing of the terminal genes in dipterans that lack Transformer orthologs and lepidopterans. Doublesex and Fruitless orthologs are the terminal genes. Doublesex and Fruitless orthologs are highly conserved zinc-finger proteins that regulate the expression of downstream proteins influencing physical traits and courtship behaviours in a sex-specific manner. Genetic pest management methods can use different mechanisms to exploit or disrupt female-specific regions of different sex determination genes. Female-specific regions of sex determination genes can be exploited to produce a lethal gene only in females or disrupted to impede female development or fertility. Reducing the number of fertile females in pest populations creates a male-biased sex ratio and eventually leads to the local elimination of the pest population. Knowledge on the genetic basis of sex determination is important to enable these sex determination pathways to be exploited for genetic pest management.
A checklist of South African bark and ambrosia beetles (Coleoptera: Curculionidae: Scolytinae, Platypodinae)
(Magnolia Press, 2025-06) Nel, Wilma Janine; Duong, Tuan A.; Fell, Shaw; Herron, Darryl A.; Paap, Trudy; Wingfield, Michael J.; De Beer, Z. Wilhelm; Hulcr, Jiri; Johnson, Andrew J.; janine.nel@fabi.up.ac.za
No abstract available.
Replacement names for the dung beetle genus Byrrhidium Harold, 1869 and the tribe Byrrhidiini Davis, Deschodt & Scholtz, 2019 (Coleoptera: Scarabaeidae: Scarabaeinae)
(Magnolia Press, 2025-03-12) Davis, Adrian L.V.; Deschodt, Christian M.; Scholtz, Clarke H.; adrian.davis@up.ac.za
Bouchard et al. (2024: 93) have pointed out that the dung beetle genus name Byrrhidium Harold, 1869 (Coleoptera: Scarabaeidae: Scarabaeinae) is a junior homonym of the pill beetle genus name Byrrhidium Heer, 1864: 64, 65 (Coleoptera: Byrrhidae). This statement is a consequence of the action by Neave (1939), who, as First Reviser (ICZN 1999: art. 24.2; hereafter cited as “the Code”), selected the spelling Byrrhidium as the valid name for the pill beetle genus out of two spellings used by Heer (1864: 64, 65, 89—Byrrhidium or Byrrhydium). As regards the name Byrrhidium for the scarabaeine dung beetle genus, it must be ascribed to Harold (1869: 96) and not to Harold in Gemminger and Harold (1869: 997) as explained by Bouchard et al. (2024: 93). They state that “this name was first used by Harold in Gemminger and von Harold (1869a: 997) but it is not available from that publication since there is no description or indication, the sole species associated with the name being a nomen nudum”. Regardless of whether the dung beetle genus name Byrrhidium is attributed to Harold in Gemminger and Harold (1869: 997) or to Harold (1869: 96), the name is a junior homonym of Byrrhidium Heer, 1864. As a junior homonym, it cannot be used as the valid name for the scarabaeine dung beetle genus. Therefore, under Article 60.2 of the Code, its junior synonym Elassocanthon Kolbe, 1908 must become the valid generic name.
Phoberus sulcatus (Thunberg, 1787) sensu lato : in-depth morphological analysis of male genitalia reveals three cryptic species (Coleoptera: Scarabaeoidea: Trogidae)
(Magnolia Press, 2025-07) Strumpher, Werner P.; Huchet, Jean-Bernard; Da Costa-Silva, Vinicius
In this study, we conducted a comprehensive review of the widely distributed keratin-beetle species Phoberus sulcatus(Thunberg, 1787) (Trogidae). Based on the examination of over 1,200 specimens across its entire known distribution range, we identified three distinct species within Phoberus sulcatus sensu lato. Consequently, Trox instabilis Haaf, 1953 is removed from synonymy with Phoberus sulcatus and formally transferred to the genus Phoberus MacLeay, 1819. Both species are redescribed and diagnosed. In addition, we describe a new species, Phoberus erwinhaafi Strümpher, sp. nov. The three species are allopatric and presently have non-overlapping distributions. Specifically, Phoberus sulcatusis confined to the Eastern Cape, KwaZulu-Natal, the southeastern part of the Northern Cape and the eastern part of the Western Cape provinces. The revalidated and recombined Phoberus instabilis (Haaf, 1953) is widespread, occurring in Botswana, Lesotho, throughout the central and eastern interior of South Africa, and Zimbabwe. Phoberus erwinhaafi Strümpher, sp. nov., represents geographically distinct populations in Namibia and South Africa’s Northern Cape province. The distributions of all three species are mapped, and a neotype is designated for the missing type specimens of Trox sulcatus (originally described as Throx sulcatus). We also include an erratum correcting an error in Strümpher & Stals (2021).
Succinate-driven cardiac mitochondrial respiration aligns with whole-animal hypoxia-tolerance in African mole-rats
(Springer, 2025) Munro, Daniel; Hart, Daniel William; Bennett, Nigel Charles; Van Jaarvsveld, Barry; Devereaux, Maiah E.M.; Campbell, Kevin L.; Sebaa, Rajaa; Van Dermeeren, Emmanuel; Harper, Mary-Ellen; Blier, Pierre U.; Pamenter, Matthew E.
Variations in environmental oxygen availability can induce oxidative stress in mammalian cells; episodes of hypoxia/re-oxygenation can be deleterious to cardiac function. Subterranean-living African naked mole-rats putatively experience repeated bouts of hypoxia/re-oxygenation in their natural habitat and are among the most hypoxia-tolerant mammals. To mitigate the potentially deleterious effects of frequent hypoxia/re-oxygenation exposure, naked mole-rats possess cardiac mitochondrial adaptations that may limit oxidative damage caused by fluctuating environmental oxygen levels. These include low respiratory flux through complex II (succinate dehydrogenase) of the mitochondrial electron transport system and robust cardiac reactive oxygen species (ROS) scavenging capacities. We hypothesized that these specializations are common traits in all hypoxia-tolerant African mole-rats. To test this hypothesis, we evaluated mitochondrial respiration and both ROS efflux and scavenging capabilities from naked mole-rats, six additional hypoxia-tolerant African mole-rat species, and hypoxia-intolerant mice (Mus musculus), rats (Rattus norvegicus; non-subterranean), and star-nosed moles (Condylura cristata; subterranean). We found a clear and inverse relationship between complex II-fuelled respiration of isolated mitochondria and hypoxia-tolerance across all species tested. Conversely, we found no relationship between hypoxia-tolerance and rates of complex I-fuelled respiration, H2O2 efflux (with any substrate), or mitochondrial H2O2 scavenging capacity. Our results suggest that downregulating the catalytic capacity of cardiac mitochondrial complex II may be an adaptation that supports systemic hypoxia-tolerance in African mole-rats.
Combination of citrus peel-derived essential oils with acarbose to inhibit amylolytic enzymes – a potential type II diabetes treatment approach
(Elsevier, 2025-05) Tshiyoyo, Kadima Samuel; Rabbad, Ali; Yusuf, Abdullahi Ahmed; Malgas, Samkelo; samkelo.malgas@up.ac.za
Type 2 diabetes (T2D) can be managed by inhibiting amylolytic enzymes, α-amylase and α-glucosidase, reducing the impact of dietary carbohydrates on blood glucose elevation. Acarbose, a current α-glucose inhibitor (AGI), has excessive α-amylase inhibition, resulting in side effects associated with large amounts of undigested starch being fermented in the colon. This study evaluated the AGI efficacy of citrus peel-derived essential oils, where they were first tested in silico against the target amylolytic enzymes, and then their AGI activity was tested in vitro. The synergistic effects of the essential oils with acarbose against amylolytic enzymes were also determined. In silico and in vitro data of the efficacy of the essential oils as AGIs correlated positively; lower Ki values correlated with more negative binding affinity. Furthermore, molecular dynamic simulations of the most potent compounds were evaluated and indicated relative flexibility and stability induced upon ligand interactions with the protein. The standard AGI drug, acarbose, had the lowest Ki (0.10 ± 0.01 mg/mL) and more negative binding affinity (−7.5 kcal/mol) than the essential oils for α-glucosidase; however, the essential oils only showed potent inhibition against α-glucosidase, with the most potent essential oils being valencene (Ki = 0.33 ± 0.04 mg/mL), carveol (Ki = 0.53 ± 0.02 mg/mL) and geraniol (Ki = 0.56 ± 0.02 mg/mL). The essential oils and acarbose displayed competitive inhibition of α-glucosidase. Furthermore, a combination of acarbose with carveol or geraniol at a ratio of 12.5 μg/mL: 2 mg/mL exhibited antagonistic (CI > 10) and synergistic (CI < 0.7) effects on α-amylase and α-glucosidase inhibition, respectively. Carveol or geraniol can be considered as potentially therapeutic in managing T2D, as it may display lowered AGI-associated side effects. HIGHLIGHTS • Terpenes were identified from Citrus peel-derived essential oils. • Some individual essential oils tolerably inhibited amylolytic enzymes. • Synergism of essential oils with acarbose against amylolytic enzymes was established. • Essential oils inhibited glucose release with reduced starch residues.

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