Research Articles (Zoology and Entomology)

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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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Territoriality in adult male sub-Antarctic fur seals at Gough Island
Bester, Marthan Nieuwoudt; Rossouw, G.J. (Springer, 2025-03)
We analysed unpublished data on territory size and tenure in adult male sub-Antarctic fur seals Arctocephalus tropicalis recorded at Gough Island, Southern Ocean, during the 1975/76 austral summer breeding season. Adult males (n=15) remained on their territories for between 35–56 days (mean 45.4±6.7 days). Territory size during the peak breeding season was 21.9 m2 on average (n=42), but when partitioned by beach type, average territory sizes were 13.8 (n=9), 20.1 (n=17) and 28.3 m2 (n=16). Both territory tenure and territory size fall within the reported range of values established in fur seal species which hold territories on land as the predominant male reproductive strategy. We highlight numerous confounding factors that impact comparative studies which should be considered when interpreting theoretical, conceptual, and modelling approaches about territorial behaviour in otariids.
Seasonal occurrence and condition of leopard seals at an extralimital Sub‑Antarctic Island
Ross, Michael D.; Leitner, Monica; Oosthuizen, W. Chris; Bester, Marthan Nieuwoudt; Jordaan, Rowan Keith; Voysey, Michael D.; Conradie, Everhard C.; Dosi, Banele; Evans, Sean; Lloyd, Kyle J.; Monier, Zafar; Purdon, Jean; Reisinger, Ryan R.; Shihlomule, Yinhla Desmond; Van der Vyver, J.S. Fredrik; De Bruyn, P.J. Nico (Springer, 2025-06)
Leopard seals (Hydrurga leptonyx) occur mainly south of the Antarctic Polar Front, but immatures, in particular, seasonally move beyond this range during the austral winter and spring, typically under increased sea ice conditions. Extralimital occurrences of leopard seals can be observed at several sub-Antarctic islands where they haul out to rest. We present new records of leopard seal sightings at Marion Island, southern Indian Ocean, from 2006 to 2024 and discuss fluctuations in their seasonal and annual abundance (drawing on data collected since 1980) and body condition based on regular surveys. The eastern beaches at Marion Island were surveyed every 7–10 days while the western beaches were visited monthly. Observed leopard seals were photographed and given a body condition score based on the visibility of bony protrusions. From 2006 to 2024, we identified 35 presumed unique immature leopard seals between July and November, with a peak in September, all being immatures. Individuals to which we could assign body condition scores were either in good or excellent condition. This contrasted with the prevailing hypothesis that leopard seal body condition deteriorates with decreasing latitude. However, we could not determine whether this was because of an actual shift in body condition or because we used a different scoring system from other studies. We recommend adopting a standardised scoring system for visually estimating pinniped body condition and a global repository to monitor leopard seal haul-outs. As an apex predator, leopard seals may be important indicators in Antarctic and sub-Antarctic ecosystems, and monitoring changes in their distribution and body condition may indicate environmental and biological changes in these remote regions.
Monitoring of vagrant seals on mid-oceanic islands of the South Atlantic Ocean
Bester, Marthan Nieuwoudt; Somers, Michael J. (Springer, 2025-09)
Extra-limital sightings of seals breeding on the Antarctic pack- and fast ice and on sub-Antarctic and temperate islands of the South Atlantic Ocean are summarised. Particular life history events of four vagrant seal species that have turned up on Mid-Atlantic Ridge islands are presented, and the likely arrival of a further three vagrant seal species is speculated upon. The setting up and/or expansion of a recording system underpinned by an appropriate sighting protocol for vagrant seals in which citizen scientists can participate is advanced. Determination of whether range contractions/expansions of seals in the South Atlantic are taking place reflects on the status of the source population(s). Seal vagrancy may conceivably also be involved in the spread of viral diseases such as highly pathogenic avian influenza and rabies. Insights gained through extra-limital sightings of seals may assist with the establishment of conservation strategies.
Smallholder farmers’ knowledge, perception and management of Spodoptera frugiperda (Lepidoptera: Noctuidae) on Zea mays at irrigation schemes in Limpopo province, South Africa
Nethononda, Phophi D.; Hurley, Brett Phillip; Slippers, Bernard; Makhura, Moraka Nakedi (Elsevier, 2026-03)
The fall armyworm (Spodoptera frugiperda) was first detected in Limpopo province, South Africa, during the 2016/2017 cropping season and continues to cause significant damage to maize production in the region. Despite the significant damage caused by S. frugiperda to maize, there is a lack of documented information on smallholder farmers' responses and control practices in South Africa. This study investigated smallholder farmers' knowledge, perceptions, and management practices of S. frugiperda at the Dzindi and the Tshiombo irrigation schemes in Limpopo province, South Africa. In this study, an irrigation scheme refers to a communal water distribution system that channels water from a river to multiple plots under smallholder cultivation through furrows or canals. Data were collected through 16 focus group discussions with farmers from the two irrigation schemes. A total of 118 farmers participated in the interviews. Each was assigned a unique identifier, which allowed for the recording and analysis of individual responses where applicable. Thematic analysis was used to identify and summarize common themes from participants’ responses, while descriptive analysis using frequencies and percentages was employed to present the responses quantitively. Farmers perceived S. frugiperda as the most destructive insect pest, yet lacked knowledge of its biology, being unable to identify its eggs, pupae, or adult moths. Control was largely through insecticide use. At the Dzindi irrigation scheme, farmers adopted Bt maize but did not comply with resistance management practices. The findings underscore the urgent need for farmer education on insect biology, responsible pesticide use, and proper implementation of Bt maize. The study also highlights the importance of collective rather than individual efforts in managing S. frugiperda, as the consequences of mismanagement can affect all farmers. These findings reveal major gaps in Integrated Pest Management (IPM) practices among smallholder farmers in Limpopo province, South Africa. HIGHLIGHTS • First detection of Spodoptera frugiperda in Limpopo Province, South Africa, occurred during the 2016/2017 cropping season. • Smallholder farmers lack knowledge of the pest's biology, relying on insecticides for its management. • Concurrent use of insecticides and Bt maize raises concerns over the potential evolution of S. frugiperda resistance in the region.
Honey bees of Ethiopia : their lineages and subspecies based on morphometrics, mitochondrial DNA, and mandibular gland pheromone analyses
Wanore, Walellign Wotro; Pirk, Christian Walter Werner; Yusuf, Abdullahi Ahmed; Baleba, Steve B.S.; Chege, Mary; Ndungu, Nelly N.; Wubie, Abebe J.; Ayalew, Workneh; Nganso, Beatrice T. (Public Library of Science, 2025-11-07)
Apiculture is a vital economic sector in Ethiopia, providing income and employment for over two million people. However, the classification of the honey bee subspecies in Ethiopia remains debatable. To shed light on this, we analysed wing geometric and classical morphometrics, mandibular gland pheromones, and COI–COII mitochondrial DNA sequences from worker honey bees collected across high, mid and low elevation gradients within Oromia, Amhara, and Southern Nations Nationalities and Peoples’ (SNNP) regions. Our results revealed significant regional morphological and pheromonal variation driven by elevation. Wing size increased with altitude, suggesting adaptive responses to elevation. Classical morphometrics supported this trend, with bees at higher elevation exhibiting larger flight structures. Regional differences in mandibular gland pheromone secretion were also observed, with workers from Amhara secreting the least quantities of these compounds, including the queen substance 9-oxo-2(E)-decenoic acid (9-ODA) and its precursor 9-hydroxy-2(E)-decenoic acid (9-HDA), as well as the worker component 10-hydroxy-2 (E)-decenoic acid (10-HDA) and its precursor 10-hydroxy-decanoic acid (10-HDAA). Furthermore, the secretion of 9-HDA and the total amount of mandibular gland pheromone significantly and negatively correlated with elevation. For mtDNA analysis, all samples from Ethiopia clustered with the Y lineage (Apis mellifera simensis) and separated from neighbouring honey bee populations of the A lineage (A. m. scutellata and A. m. monticala). Overall, our results reveal the significant influence of elevation on adaptive traits of Ethiopian honey bees, which are of the same subspecies.
Development of an 11-oxoetiocholanolone mini-kit for the quantification of faecal glucocorticoid metabolites in various wildlife species
Edwards, KatieL.; Wheaton, Catharine J.; Brown, Janine L.; Dimovski, Alicia M.; Fanson, Kerry V.; Ganswindt, Andre; Ganswindt, Stefanie Birgit; Hagenah, Nicole; Keeley6, Tamara; Möstl, Erich; O’Hara, Bobbi; Penfold, LindaM.; Shablin, Samantha A.; Palme, Rupert (Oxford University Press, 2025-10)
As part of its mission to advance the field of wildlife endocrinology, the International Society of Wildlife Endocrinology aims to develop cost-effective antibodies and enzyme immunoassay kits that support research across a diverse range of species and sample matrices. To provide additional options for the quantification of faecal glucocorticoid metabolites (fGCMs), an antibody against 11-oxoetiocholanolone-17-carboxymethyl oxime (CMO) was generated in rabbits, and an enzyme immunoassay incorporating a horseradish peroxidase-conjugated label and 11-oxoetiocholanolone standard has been developed, designed for use with anti-rabbit IgG secondary antibody coated plates. This mini-kit was used to quantify glucocorticoid metabolites with a 5β-3α-ol-11-one structure in faecal extracts from 23 species: African and Asian elephants, Alpine chamois, American bison, Bengal tiger, blue wildebeest, blue-and-yellow macaw, brushtail possum, cape buffalo, fat-tailed dunnart, Florida manatee, ghost bat, giraffe, golden langur, Gould’s wattled bat, hippopotamus, Leadbeater’s possum, mandrill, okapi, roan antelope, samango monkey, short-beaked echidna, and western lowland gorilla. Pharmacological (adrenocorticotropic hormone challenge) and biological (inter-zoo translocation, wild capture, social disruption, illness/injury and veterinary intervention) challenges resulted in expected increases in fGCM concentrations, and in a subset of species, closely paralleled results from a previously established immunoassay against 11-oxoetiocholanolone-17-CMO. Two additional species tested, Krefft’s glider, which showed contradictory results on this assay compared to a previously validated enzyme immunoassay (EIA) and Ankole cow, where the magnitude increase post-event did not quite reach the 2-fold change criteria, highlight that differences in excreted faecal metabolites across species mean that no EIA will be suitable for all species. This assay provides a valuable new option for assessing adrenal activity across taxa using a group-specific antibody. Future studies should put similar emphasis on validation to determine optimal assay choice for measuring fGCMs in a variety of species.
Improvement of colony management in insect mass-rearing for sterile insect technique applications
Abd-Alla, Adly M.M.; Geiger, Anne; Haymer, David; Herrero, Salvador; Jehle, Johannes A.; Khamis, Fathiya Mbarak; Liedo, Pablo; Malacrida, Anna R.; Njiokou, Flobert; Mastrangelo, Thiago; Pagabeleguem, Soumaila; Ramirez-Santos, Edwin M.; Ros, Vera I.D.; Segura, Diego F.; Tsiamis, George; Weiss, Brian L. (Wiley, 2025-10)
Sterile Insect Technique (SIT) applications against major insect pests and disease vectors rely on the cost-effective production of high-quality sterile males. This largely depends on the optimal management of target pest colonies by maximizing the benefits provided by a genetically rich and pathogen-free mother colony, the presence of symbiotic microorganisms, and efficient domestication, mass-rearing, irradiation, and release processes. At the same time microbial (bacteria, fungi, microsporidia, and viruses) pathogen outbreaks should be minimized or eliminated, and the use of hazardous chemicals restricted. The optimization of the colony management strategies for different SIT target insects will ensure a standardized high-quality mass-rearing process and the cost-effective production of sterile males with enhanced field performance and male mating competitiveness. The aims of the Coordinated Research Project (CRP) were to develop best practices for insect colony management for the cost-effective production of high-quality sterile males for SIT applications against major insect pests and disease vectors through a multidisciplinary approach involving entomologists, geneticists, ecologists, microbiologists, pathologists, virologists, and mass-rearing experts.
Prostephanus truncatus outcompetes Sitophilus zeamais under varying temperatures and introduction sequence on stored maize grain
Mlambo, Shaw; Mvumi, Brighton M.; Machekano, Honest; Nyamukondiwa, Casper (Elsevier, 2026-01)
Coexistence of insect pests can result in facultative or antagonistic interactions. For sympatric pest species, explaining coexistence is crucial for understanding their combined impact, resource competition, and may inform management strategies. Prostephanus truncatus and Sitophilus zeamais commonly coexist as primary colonisers in stored maize grain. To determine how these species interact, two experiments mimicking competition scenarios on stored grain were conducted at 25, 30 and 35 °C (65 % RH). In Experiment 1, P. truncatus and S. zeamais were introduced simultaneously (interspecific) and in singular (intraspecific) populations at low (20), medium (40), and high (80) parental densities. In Experiment 2, we used similar temperatures and parental densities. However, one species was introduced 10 days after the other, and vice versa. Mini-polypropylene bags, each loaded with 65 ± 5g of dried orange maize grain, were used for both experiments. Progeny production, grain damage, grain weight loss, insect feeding dust and holes on bags bored by beetles, were recorded after 65 days of storage. Results showed that (i) P. truncatus outcompeted S. zeamais in interspecific interactions at 25 and 30 °C across parental densities, (ii) both species’ ecological performances were suppressed at 35 °C, (iii) P. truncatus caused higher grain damage regardless of the introduction sequence with S. zeamais and (iv) P. truncatus dispersed by tunnelling through polypropylene bags to avoid competition. Understanding interactions among sympatric pest species is essential for accurately predicting infestation outcomes and developing effective pest management under increasingly warming environments. HIGHLIGHTS • P. truncatus outcompeted S. zeamais across different temperatures and parental densities. • Ecological performance was suppressed at 35 °C for both P. truncatus and S. zeamais. • Sequence of introduction did not reduce P. truncatus competitive advantage over S. zeamais. • Tunneling was competition-induced and could trigger P. truncatus dispersal.
Staying alive : individual behavioral variation influences survival, but not reproductive success, in female group-living ground squirrels
Warrington, Miyako H.; Van der Marel, Annemarie; Sojka, Jennifer; Shofstall, Krista J.; Waterman, Jane M. (Wiley, 2025-07)
Animals living in harsh or unpredictable environments adopt adaptive strategies to improve their fitness, with behavioral variation playing a key role in shaping individual outcomes. We examined whether between-individual variation in behavioral traits (personality) was associated with reproductive success and survival in female Cape ground squirrels (Xerus inauris). Using a 10-year dataset (2011–2021), we quantified behavioral expressions of the animal's response to trapping and handling (trap response, as a proxy for docility), trapping rate (trappability, for boldness) and the number of different trapping locations an animal was trapped at (trap diversity, for exploration) and examined their associations with (1) annual reproductive success, (2) lifetime reproductive success, (3) annual survival, and (4) on-site persistence (a proxy for lifespan). Response measures taken during transfer from the cage, handling by a human observer, and whether individuals ran or walked after release were moderately repeatable. Trappability was also repeatable, while trap diversity was not. Trap response and trappability were positively correlated with survival, but not reproductive success. Females that easily transferred from the trap to the handling bag (more docile) had higher annual survival, while those that ran after release had longer lifespans. Individuals trapped at a higher rate (bolder) had higher annual survival. The absence of a relationship between behavioral traits and reproductive success in females suggests that other factors, such as group dynamics, social interactions, and maternal effects, may be more influential in explaining the high reproductive skew in female reproductive success. Overall, our findings highlight the role of individual behavioral variation in shaping survival outcomes while emphasizing the need for further research into the mechanisms driving reproductive success in this species.
Monthly and diel acoustic occurrence of four Baleen whale species in South African waters
Shabangu, Fannie Welcome; Hlati, Kuhle; Van den Berg, Marcel A.; Lamont, Tarron; Kirkman, Stephen P. (Wiley, 2025-08)
Understanding of the spatio-temporal occurrence of cetaceans post the whaling era is essential for protecting and improving management strategies of these marine mammals. To determine the monthly and diel acoustic occurrence of four baleen whale species relative to environmental conditions off the west coast of South Africa, we collected passive acoustic monitoring data within Child's Bank marine protected area in January and May through October 2024 at various water depths. Burst tonal calls of the southern African Bryde's whale offshore population were detected in January and May through July with the highest occurrence in January. Humpback whale songs and southern right whale gunshot sounds were detected from May through October with high occurrence in September and with smaller modes in other months. Antarctic minke whale bioduck calls were also found in June through October, showing high occurrence in August through October. Calls from an unknown source with similar characteristics to Antarctic minke whale bioduck calls were present in May, July, and August with the highest occurrence in August. Diel acoustic occurrence of Bryde's, southern right, Antarctic minke, and minke-like whale calls indicated that these animals vocalised more during the day while humpback whales were more vocally active at night. Sea surface height and sea surface temperature, either separately or in combination, were the most important predictors of whale acoustic occurrence, highlighting the influence of environmental conditions on the distribution, habitat selection, and ecology of these whales. Overall, this study advances our understanding of the movement, occurrence, and behavioural patterns of several baleen whales relative to environmental conditions. It also provides the first description of the southern African Bryde's whale offshore population's call characteristics, which will be useful at guiding future studies to acoustically differentiate between it and the inshore population.
Interspecies haptic sociality : an observation of grooming between two mongoose species
Smith, Kyle; Hepplewhite, Malcolm; San, Emmanuel Do Linh; Somers, Michael J. (Wiley, 2025-06)
Meerkats (Suricata suricatta) and yellow mongooses (Cynictis penicillata) share many behavioural characteristics and are known to, on rare occasions, live in close association through displayed cooperative vigilance and shared burrow use. Here, we describe the first visual observation of tactile social behaviour through grooming between a meerkat and a yellow mongoose in the Rietvlei Nature Reserve, South Africa. We hypothesise that the close relationship between the two species in the reserve may be a response to a combination of phylogenetic ties, shared behavioural traits, and the population collapse of meerkats in the reserve that exposed a vacant social niche. This observation of interspecific sociality further extends our knowledge of cooperation and group augmentation among meerkats, yellow mongooses and carnivores in general.
Despite potential risks African elephants do not always avoid mountaineering
Teixeira, Justine M.; Van der Westhuizen, Rickert; Shrader, A.M. (Adrian) (Wiley, 2025-07)
As herbivores forage, they move across a wide range of topographical features. Yet, they tend to avoid terrain such as steep slopes where energetic costs of movement are high and there is a greater risk of falls and tumbles. Recent studies suggest that African elephants (Loxodonta africana) avoid steep slopes (e.g., > 15°). However, in reserves with undulating topography, elephants may have to use steep slopes to obtain food, especially when availability is limited in more gradual areas. To explore this, we investigated slope use by elephants in the Ithala Game Reserve, South Africa, where the topography varies greatly and ranges between 400 to 1400 masl. Using 8.5 years of positional data, we examined how slope use varied between herd types (14 breeding herds and 13 males), habitat type and season (wet vs. dry). Elephants were found primarily on slopes < 30° (i.e., 95% of the locations), while 67% of the locations were on slopes < 15°, and 52% on slopes < 10°. Breeding herds used steeper slopes (mean = 12.6° ± 0.08 SE) than bulls (mean = 12.0° ± 0.8 SE). In addition, habitat influenced slope use, with the steepest slopes used in woodlands and the most gradual used in built-up areas and grasslands. However, these slope use differences were very small (i.e., 0.6° to 9.7°) and thus unlikely to be biologically meaningful. Rather, the ability to detect these slight differences was likely an artefact of our large sample size (N = 23,837 locations). Moreover, slope use did not vary between the wet and dry seasons. Nevertheless, 5% of all the elephant locations occurred on very steep slopes (i.e., > 30°) and 33% were on slopes > 15°, indicating that although they may prefer flat terrain, when required, elephants will mountaineer.
Threatened endemic arthropods and vertebrates partition their diets with non-native ants in an isolated island ecosystem
Tercel, Maximillian P.T.G.; Cuff, Jordan P.; Symondson, William O.C.; Moorhouse-Gann, Rosemary J.; Bishop, Tom Rhys; Cole, Nik C.; Jolin, Eric; Govier, Bethan; Chambon, Johannes; Mootoocurpen, Rouben; Goder, Martine; Vaughan, Ian P. (Wiley, 2025-07)
The success of non-native species depends on their ability to find food, which may ultimately lead to competition with native species and contribute to biodiversity loss in invaded ecosystems. Understanding which food resources are consumed is therefore crucial for evaluating how non-native species mechanistically fit into native biological communities. Non-native species may be predators or competitors of native species or may be consumed by native species as a novel source of nutrition, for example, and this can occur between both closely and distantly related species. Studies examining competitive interactions between non-native species and distantly related native taxa are relatively rare, largely because it is difficult to compare their diets using traditional methods. However, dietary DNA metabarcoding overcomes these limitations by enabling the construction of highly detailed food webs. Here, we use dietary DNA metabarcoding between two generalist native consumers—a reptile (Telfair's skink) and a Scolopendra centipede (Serpent Island centipede)—and the hyperabundant non-native ant community to test which consumer groups prey upon one another and partition food resources. To determine how non-native ants fit into a native community, we calculated dietary composition, niche overlap, and dietary diversity of ants, centipedes, and skinks on Round Island, a small 2.19-km2 oceanic island located 22.5 km north-east of Mauritius. We observed distinct partitioning of food resources among the three consumer groups—skinks, centipedes, and ants—and found that the level of predation between these groups varied. Skinks and centipedes frequently consumed non-native ants, which may represent an important nutritional resource for both native consumers. Dietary differences persisted through seasons despite large shifts in the availability of food and concomitant diet composition for all three consumers. We conclude that non-native ants fit into the biological community of Round Island as both prey for native consumers and extreme omnivorous generalists, but not necessarily at the expense of the native consumers because it is unlikely the consumers are competing for food resources. Our results suggest that abundant non-native generalists, which are highly invasive in much of their introduced range, can infiltrate native food webs without exerting strong competitive forces on other common native generalist species.
Creating the vision of rapid, repeatable, reactive data workflows for policy on biodiversity
Groom, Quentin; Abraham, Laura; Adriaens, Tim; Breugelmans, Lissa; Clarke, David A.; Di Musciano, Michele; Dove, Shawn; Estupinan-Suarez, Lina M.; Faulkner, Katelyn T.; Fernandez, Miguel; Hendrickx, Louise A.; Hui, Cang; Joly, Alexis; Kumschick, Sabrina; Langeraert, Ward; Martini, Matilde; Miller, Joe; Oldoni, Damiano; Pereira, Henrique; Preda, Cristina; Robertson, Tim; Rocchini, Duccio; Rodrigues, Andrew; Ryckewaert, Maxime; Seebens, Hanno; Sica, Yanina V.; Teixeira, Heliana; Trekels, Maarten; Vandaele, Toon; Wilson, John R.U.; Zengeya, Tsungai; Desmet, Peter (Wiley, 2025-07)
1. Effective biodiversity management and policymaking requires timely access to accurate and reliable scientific data on biodiversity status, trends and threats. However, current biodiversity monitoring processes are often time-consuming, complex and irreproducible. Moreover, the quality and types of biodiversity data are diverse, which challenges their integration and impedes effective monitoring. A major step to overcome such challenges would be the availability of standardized species occurrence data. However, challenges arise in aggregating and integrating these heterogeneous data with environmental and landscape data. 2. By creating standardized biodiversity data cubes and automated workflows for post-processing, we envision that (1) information from complex datasets will be available in a known format to efficiently communicate biodiversity variables to policymakers; (2) the adoption of repeatable Open Data workflows will make biodiversity data more accessible, efficient and cost-effective; and (3) cloud computing will make it easier to analyse large datasets, benefit from a broader range of models, share resources and work together on biodiversity projects. 3. This revolution in biodiversity monitoring will rely on community collaboration. By bridging the gap between policymakers' needs, bioinformation specialists' skills and data collectors' motivations, biodiversity monitoring can become a more inclusive and community-driven effort. As such, we advocate for the development of tools and workflows in close consultation with stakeholders to enhance the impact and use of biodiversity information. 4. Practical implication. The proposed approach faces challenges in maintaining software, data standards and addressing biodiversity data complexity. However, leveraging existing infrastructures like GBIF and Copernicus, and building on the knowledge from GEO and GEO BON offers a feasible path.
Assessing Gonipterus defoliation levels using multispectral unmanned aerial vehicle (UAV) data in Eucalyptus plantations
Nzuza, Phumlani; Schröder, Michelle L.; Heim, Rene J.; Daniels, Louis; Slippers, Bernard; Hurley, Brett Phillip; Germishuizen, IIaria; Sivparsad, Benice; Roux, Jolanda; Maes, Wouter H. (Elsevier, 2025-12)
Invasive insect pest Gonipterus sp. n. 2 (Coleoptera: Curculionidae) threatens Eucalyptus species, causing defoliation and yield loss through adult and larval feeding. Early detection is important for early intervention to prevent pest outbreaks. As conventional insect pest monitoring methods are time-consuming and spatially restrictive, this study assessed the potential of UAV monitoring. Multispectral imagery was obtained with Unmanned Aerial Vehicles (UAVs) across six different stands of young Eucalyptus dunnii with varying levels of Gonipterus sp. n. 2 infestations. Some stands were revisited, a total of 9 datasets were covered. Reference damage levels were obtained through visual assessments of (n = 89–100) trees at each site. Across sites, a decrease in canopy reflectance in both the visual and the near-infrared domains with increasing damage levels was consistently observed. Several vegetation indices showed consistent patterns, but none showed site independence. XGBoost, Support Vector Machine and Random Forest (RF) were used to predict damage levels using five input spectral data types. XGBoost performed best, closely followed by RF. Both models consistently selected very similar features. The best-performing models included reflectance, vegetation indices and grey-level co-occurrence matrix data. When data from 10 different wavelengths were used, the highest classification accuracy was 92 % across all sites in classifying defoliation levels. With a classical 5-band multispectral camera, accuracy was 88 %, but distinguishing medium damage from low remained challenging. However, the method was less reliable when trained and validated on separate fields. This study highlights the potential of multi-site datasets in increasing the model's generalization, using UAV based multispectral imagery to assess Gonipterus sp. n. 2 damage and demonstrating reliable upscaling from individual tree assessments to stand scale. However, it also recognises the difficulty of generating a robust model that performs well on untrained sites. HIGHLIGHTS • Canopy damage from Gonipterus sp. n. 2 was assessed across stands using UAV imagery, capturing defoliation, chlorophyll reduction. • The 5-band imagery perfomed comparable to the 10-band but was less effective at detecting subtle low vs no damage defoliation. • Similar pattern was observed across sites but absolute reflectance and vegetation indices are site specific.
The preference for energetic resources is positively associated with predatory activity in ants
Wilker, Icaro; Bishop, Tom Rhys; Lasmar, Chaim J.; Veiga, Dara; Souza, Leticia G.; Queiroz, Antonio C.M.; Feitosa, Rodrigo M.; Neundorf, Ana C.A.; Martins, Mila F.O.; Alves, Guilherme P.; Fontenele, Luane K.; Costa, Marilia M.S.; Ribas, Carla R. (Wiley, 2025-10)
1. Land use changes can alter resource availability and microclimate variables in tropical ecosystems, generally altering community structure by decreasing species richness and changing its composition. These changes affect foraging activity, nutrient preferences and consequently ecosystem functions. 2. Our aim was to assess how foraging activity and nutrient preference are influenced by changes in land use and microclimate. 3. We sampled ants (Formicidae) at 32 sites undergoing conversion from natural habitats to coffee systems in two Neotropical biomes: the Atlantic rainforest and the Cerrado. We assessed nutrient preference (amino acids, carbohydrates, lipids and sodium) and predation using mealworm larvae, while also measuring temperature and humidity. 4. We found the same ants foraged for different resources, likely because generalist species can perform these activities on the ground. Furthermore, foraging for energetic resources (carbohydrates and lipids) positively correlated with foraging for larvae. This indicates that the limitation of energetic resources can contribute to an increase in foraging and predatory activity. Moreover, ant preference for amino acids decreases with increasing temperature, indicating that ants prefer to consume energetic resources to support metabolic processes. 5. In conclusion, foraging is primarily carried out by generalist species. In addition, the preference for energetic nutrients, driven by energetic limitations, is linked to predatory activity. Moreover, ant species richness increases foraging for larvae, while rising temperatures decrease the preference for amino acids. Thus, conserving species richness and mitigating temperature increases may enhance larval foraging and support the insect predation function in Neotropical habitats.
Spatially-differentiated regulation of alien species can be improved using species distribution models : Psidium guajava in South Africa as a case study
Mbobo, Tumeka; Richardson, David M.; Datta, Arunava; Faulkner, Katelyn T.; Wilson, John R.U. (Wiley, 2025-10)
AIM : Biological invasions can generate conflicts between those who benefit from alien taxa and those threatened by subsequent invasions. Ideally, regulations should be proportionate to the level of threat—regulations perceived as unwarranted are likely to result in conflicts. We explore options for spatially differentiated regulation of alien species using Psidium guajava as a case study. LOCATION : South Africa. METHODS : Using various sources, we mapped sites across the country where guava is cultivated, naturalised, and has formed invasive monocultures. We identified areas under threat of invasions using species distribution models (SDMs). RESULTS : Our models predict that guava invasions are likely along South Africa's east coast. However, the niche dynamic indices indicate a larger cultivated niche than a naturalised niche, suggesting that there are areas in South Africa suitable for guava cultivation where invasions are unlikely. Our SDMs suggest that almost half the area regulated at the provincial level does not require regulation; this spatial over-regulation could be reduced to ~20% if regulations were at the next lower political level. CONCLUSIONS : We recommend that current regulation of guava be aligned to the level of threat. For example, guava is currently regulated in the North-West province, but we found no records of naturalisation and SDMs suggest the climate is not suitable. However, we note a trade-off between the resolution of the regulations and enforceability. We argue that: at lower levels there will be dispersal of fruits between unregulated and regulated areas as the distances between areas will be short; the SDMs produced here are not of sufficient resolution to accurately predict local conditions; and very localised variations in regulations will be complicated to enforce. Although SDMs can easily be over-interpreted, we believe that their judicious use provides a valuable method of interpreting field information in a form useful for regulators so conflicts can be avoided.
Effective homemade V8 juice formulation as alternative suitable medium for culturing Phytophthora infestans
Muhorakeye, Marie C.; Namikoye, Everlyne S.; Khamis, Fathiya Mbarak; Wanjohi, Waceke; Akutse, Komivi S. (Springer, 2025-10)
A suitable growth medium is essential for isolating, studying, and managing pathogens. To mitigate the importation dependence and availability of commercial V8 growth medium, three V8 juice formulations (F1, F2, and F3) were developed and tested in this study for their potential to stimulate the growth and sporulation of Phytophthora infestans at different growing temperatures in comparison with commercial V8 juice formulation. The results showed that the three V8 juice forms successfully induced the growth and sporulation of P. infestans at varied temperature regimes. However, V8 juice F2-based medium significantly caused quicker growth of P. infestans and increased in number and size of sporangia as well as the commercial formulation (FC) of V8 juice. In addition, the pathogen successfully grew at 15 ± 2 °C, 20 ± 2 °C, and 25 ± 2 °C; however, the plates incubated at 20 ± 2 °C displayed faster growth of the colony as compared to those incubated at the other two temperatures. Furthermore, more spores were obtained on the plates incubated at 15 ± 2 °C compared to the plates incubated at 20 ± 2 °C and 25 ± 2 °C. Overall, the V8 F2-based media was more suitable for P. infestans growth and sporulation. This finding is critical since it helps to lessen reliance on V8 juice imports and increases available V8 juice to culture or mass produce the pathogen. Consequently, further research is encouraged for sustainable management of P. infestans. HIGHLIGHTS • Homemade V8 alternative formulations support P. infestans growth and sporulation. • However, F2 formulation performs similarly to the commercial with quicker growth and increased number and size of sporangia. • The pathogen grew best at 20 °C, but produced more spores at 15 °C. • Local V8 alternatives can minimize dependency on imports and support future research on managing the pathogen.
A database on the historical and current occurrences of snakes in Eswatini
Monadjem, Ara; Boycott , Richard C.; Litscha-Koen, Thea; Kane, Adam; Dlamini, Wisdom M.; Mmema, Lindelwa; Strutton, Katharine L.; Hlophe , Zakhele; Padidar, Sara (Oxford University Press, 2025-07)
Snakes are among the most difficult terrestrial vertebrates to survey, resulting in poor distributional information on most species. This database comprises of 3812 records of 58 species of snakes in 37 genera reported from within the boundaries of Eswatini. The data were compiled from multiple sources including museum specimens, iNaturalist records, literature records, and snake rescue operations. For each specimen reported in the database, we provide the scientific name, latitude and longitude coordinates, and location. Most records also have an associated date. This comprehensive database will be useful to biodiversity experts, conservationists, medical practitioners, researchers, and snake enthusiasts, especially for mapping and modelling snake distributions in the country. To allow easy viewing of the distribution of snakes in the country, we provide an online visualization tool, which should allow a greater number of non-scientists to utilize this database.
Enhancing plantation forest sustainability : a review of Eucalyptus defence mechanisms to foliar fungal pathogens
Solis, Myriam; Hammerbacher, Almuth; Wingfield, Michael J.; Naidoo, Saloshnee (Springer, 2025-02)
PURPOSE OF THE REVIEW : In this review, we synthesize knowledge generated over many decades on the main defence responses of Eucalyptus to fungal leaf pathogens with the aim of identifying targets for breeding disease tolerant trees. We highlight physiological and molecular traits associated with host defence in relation to pathogen life-style. Overall, the purpose of this review is to identify resistance mechanisms that offer improved resilience of Eucalyptus plantations in the face of increasing threats by foliar fungal pathogens. The broad aim is to promote sustainable forestry through appropriate selection of resistance traits in trees that are widely planted for commercial timber production. RECENT FINDINGS : Eucalyptus is among the most important tree genera planted for commercial timber production worldwide. Numerous foliar pathogens have been reported on these trees in the last 30 years with numbers of recent reports increasing exponentially. The majority of these diseases affect the leaves and shoots of the trees. Knowledge on resistance traits in Eucalyptus to fungal foliar pathogens is limited. This is in part due to the high intra- and inter-species variation in molecular and physiological responses of the host and variation in responses to different pathogens, especially those with different trophic modes. A well-founded understanding of such host responses will provide valuable knowledge required to maintain healthy, sustainable Eucalyptus plantations, especially in the face of changing environmental conditions, where new diseases are caused by fungi previously not considered relevant. SUMMARY : Foliar diseases are among the most important challenges for Eucalyptus plantations globally. The effects of climate change and new or more serious outbreaks present an important threat to the sustainability of Eucalyptus plantations worldwide. Due to restrictions on the use of chemicals, more feasible solutions for disease management lie in selecting planting material with resistance traits. To achieve that goal, it is essential to understand the most important physiological and molecular responses of Eucalyptus to infection by pathogens that infect their foliar tissues. In this review we summarise the available knowledge of the main physiological defence barriers and genetic traits that play key roles in the broad defence against foliar fungal pathogens. Furthermore, we consider defence pathways that are specifically related to the lifestyle and trophic mode of the pathogens. In order to ensure the future sustainability of Eucalyptus plantations, it will be necessary to understand how disease resistance is affected by climate change, as well as the adaptability of the hosts and pathogens to newly emerging environmental conditions.

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