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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Mulching of post-harvest residues and delayed planting improves fungal biodiversity in South African Eucalyptus plantations and enhances plantation productivity
(Elsevier, 2025-06) Bose, Tanay; Roux, Jolanda; Titshall, Louis; Dovey, Steven B.; Hammerbacher, Almuth; tanay.bose@fabi.up.ac.za
Short-rotation Eucalyptus plantations provide essential forest products, with productivity and soil health influenced by residue management and planting strategies. This study examined the effects of burning or mulching post-harvest residue followed by immediate versus delayed planting on soil fungal biodiversity, soil properties, and tree growth across four sites in KwaZulu-Natal, South Africa. Plots were planted either three months ('immediate') or six months ('delayed') after treatment implementation. Volume measurements assessed tree growth, and soil attributes, including moisture, temperature, and nutrient levels, were analyzed. Soil samples were collected in November 2019 and March 2022, and fungal communities were analyzed through high-throughput sequencing targeting the internal transcribed spacer 1 (ITS1) region. Data emerging from this study showed mulched plots had significantly higher tree volume, with delayed planting increasing productivity by 13.6 % at 24–36 months and 25 % at 36–48 months post-planting. Soil moisture was 1.3–2 times higher in mulched plots than in burnt plots. Mulching significantly reduced the maximum soil temperatures by 4.5–6.8 °C. Four months after treatment, burnt plots had higher pH (1.1-fold), carbon (2.2-fold), phosphate (1.6-fold) and manganese (2.5-fold). Initially, mulched plots had lower fungal biodiversity (0.81-fold) than burnt plots but surpassed them after 28 months (1.28-fold increase). Fungal community overlap declined from 83.28 % to 40.64 %, with mulching supporting higher saprotroph (1.3-fold) and symbiotroph (1.25-fold) abundances, while delayed planting increased pathotroph presence by 1.5-fold in burnt plots. These findings highlight the long-term benefits of mulching and delayed planting in enhancing fungal biodiversity, promoting beneficial microbial communities, and improving tree growth, contributing to more sustainable Eucalyptus plantation management.
Oxidative stress in the reproduction of mammals
(MDPI, 2025-03) Jacobs, Paul Juan; Bennett, Nigel Charles; pj.jacobs@up.ac.za
No abstract available.
An assessment of vegetable production constraints, trait preferences and willingness to adopt sustainable intensification options in Kenya and Uganda
(Frontiers Media, 2025-04) Okoma, Rose N.; Omuse, Evanson R.; Mutyambai, Daniel M.; Beesigamukama, Dennis; Murongo, Marius F.; Subramanian, Sevgan; Chidawanyika, Frank
Global food production systems are under pressure due to population increase, limited farmland, biotic and abiotic constrains, and ongoing climate change. Sustainable intensification is needed to increase agricultural productivity with minimal adverse environmental and social impacts. Vegetable-integrated push pull (VIPP) technology coupled with black soldier fly (BSF) frass offer such opportunities to smallholder farmers. However, farmers’ vegetable preferences and willingness to adopt these innovations remain unknown and are variable across various geographic scales. Focus group discussions (FGDs) and in-person interviews with smallholder farmers were conducted to assess vegetable production constraints and select vegetables to be integrated into VIPP coupled with BSF frass biofertilizer in Kenya and Uganda. Twenty-six FGDs followed by in-person interviews were conducted from July to November 2023 with 227 and 106 farmers from Kenya and Uganda, respectively. A total of 23 vegetable types were identified. The most considered discerning parameters and traits included household consumption, income generation, nutritional value, extended harvesting, drought tolerance and resistance to diseases and insect pests. The major constraints were the high cost of agrochemicals and fertilizers and poor seed quality in Kenya while diseases, pests, drought and poor rainfall, low soil fertility, too much rainfall and floods, high cost of agrochemicals and fertilizers, lack of seeds and poor seed quality were pressing constraints among farmers in Uganda. More than 83% of farmers showed readiness to adopt a combination of VIPP+BSF. Kales, spinach, cabbage, Amaranthus, African nightshade and tomatoes were preferred in central Kenya whereas cowpeas, kales, African nightshade, Amaranthus, pumpkin leaves and spider plants in western Kenya were preferred as vegetables to be included in VIPP and BSF frass innovations. Ugandan farmers considered eggplants, Amaranthus, garden eggs, cabbage, kales and tomatoes the most popular vegetables to be incorporated in VIPP and BSF frass innovations. Our results provide a baseline for vegetables to be integrated into VIPP with BSF frass biofertilizer for validation with farmers. The study also underlies how farmer crop preferences vary according to site and the need for participatory selection to increase the chances of adoption of agricultural interventions.
Production of fusel alcohols and fusel acetates by pathogenic fungi in the Ceratocystidaceae
(Elsevier, 2025-08) Mailula, Dineo M.; Wingfield, Brenda D.; Van der Nest, Magrieta Aletta; Hammerbacher, Almuth; almuth.hammerbacher@fabi.up.ac.za
The family Ceratocystidaceae includes economically important plant pathogens that vary in host preference and lifestyle. These fungi are believed to attract insect vectors, for their dispersal through their floral and fruity scents. This study aimed to identify the volatiles produced by a subset of fungi within the Ceratocystidaceae using gas chromatography coupled with mass spectrometry. The primary volatiles produced by most genera in the family were fusel alcohols and fusel acetates, but their emission rates differed significantly between genera and isolates from a single species. Ceratocystis albifundus collected from Protea cynaroides produced higher levels of fusel acetates compared to isolates from Terminalia sericea. In addition, significant differences in volatile biosynthesis were observed between isolates grown under different temperatures. Results of this study demonstrate that Ceratocystidaceae exhibit varied volatile profiles, but further research is needed to understand the ecological and physiological mechanisms underlying this plasticity.
The latitudinal biotic interaction hypothesis revisited : contrasting latitudinal richness gradients in actively vs. passively accumulated interaction partners of honey bees
(BioMed Central, 2025-03) Cirtwill, Alyssa R.; Roslin, Tomas; Pena-Aguilera, Pablo; Agboto, Agathe; Berce, William; Bondarchuk, Svetlana N.; Brodschneider, Robert; Heidari, Behzad; Kaizirege, Camara; Nyaga, Justine Muhoro; Ekpah, Ojonugwa; Gomez, Gonzalo Ossa; Paz, Claudia; Pirk, Christian Walter Werner; Salehi-Najafabadi, Amir; Salonen, Anneli; Soloniaina, Chantal; Wirta, Helena
BACKGROUND : Contrasting hypotheses suggest that the number of biotic interactions per species could either increase towards the equator due to the increasing richness of potential interaction partners (Neutral theory), or decrease in the tropics due to increased biotic competition (Latitudinal Biotic Interaction Hypothesis). Empirical testing of these hypotheses remains limited due to practical limitations, differences in methodology, and species turnover across latitudes. Here, we focus on a single species with a worldwide distribution, the honey bee (Apis mellifera L.), to assess how the number of different types of interactions vary across latitudes. Foraging honey bees interact with many organisms in their local environment, including plants they actively select to visit and microbes that they largely encounter passively (i.e., unintentionally and more or less randomly). Tissue pieces and spores of these organisms are carried to the hive by foraging honey bees and end up preserved within honey, providing a rich record of the species honey bees encounter in nature. RESULTS : Using honey samples from around the globe, we show that while honey bees visit more plant taxa at higher latitudes, they encounter more bacteria in the tropics. CONCLUSIONS : These different components of honey bees’ biotic niche support the latitudinal biotic interaction hypothesis for actively-chosen interactions, but are more consistent with neutral theory (assuming greater bacterial richness in the tropics) for unintentional interactions.
In memory of Sue Nicolson
(NISC (Pty) Ltd and Informa UK Limited (trading as Taylor and Francis Group), 2024-10) McKechnie, Andrew E.; Crewe, Robin M.; Pirk, Christian Walter Werner; Human, Hannelie; Scholtz, Clarke H.; andrew.mckechnie@up.ac.za
With the passing of Professor Sue Nicolson on 27 April 2023, South Africa’s zoological community lost a respected and internationally acclaimed leader in evolutionary and ecological physiology. Sue was born in Dargaville, New Zealand in 1950 and earned a PhD in insect physiology from the University of Cambridge before moving to the University of Cape Town (UCT) in 1978. After initially being employed as a research assistant to pioneering desert biologist Professor Gideon Louw, Sue was appointed as a senior lecturer in 1990. The UCT Department of Zoology remained her academic home until the end of 2000, when she moved to the University of Pretoria’s (UP) Department of Zoology and Entomology.
Volatile odours reflect breeding status but not social group membership in captive Damaraland mole-rats
(Elsevier, 2025-04) Nichols, Hazel J.; Caspers, Barbara A.; Arbuckle, Kevin; Bennett, Nigel Charles; Hoffman, Joseph I.
In mammals, olfaction plays a key role in social behaviour, for example, in identifying mating opportunities and potential rivals. However, we still have a limited understanding of how social information is encoded in animal odours, including the social determinants of chemical similarity and diversity. Here, we used gas chromatography to analyse the chemical composition of swabs taken from the facial and anogenital regions of Damaraland mole-rats, Fukomys damarensis, a highly social subterranean mammal that relies almost exclusively on olfactory and tactile social cues. We found no sign of individual identity across the two body areas sampled; samples from the facial region and samples of the anogenital region from the same individual were not similar to each other, suggesting that these regions carry different information. However, chemical profiles varied significantly by sex and breeding status; female breeders differed from nonbreeders in their anogenital profiles and had higher chemical diversity in their facial profiles compared with both males and nonbreeders. Interestingly, we found no signals of social group identity. Instead, individual identity may be conveyed through signature mixes that are learned through frequent contact, rather than through specific odours associated with genetic kinship or social group membership. Our results highlight the complexity of chemical communication systems in social species and suggest that signals of group level identity are not necessary for behavioural responses based on group membership.
Local nutrient addition drives plant diversity losses but not biotic homogenization in global grasslands
(Nature Research, 2025-05) Chen, Qingqing; Blowes, Shane A.; Harpole, W. Stanley; Ladouceur, Emma; Borer, Elizabeth T.; Macdougall, Andrew S.; Martina, Jason P.; Bakker, Jonathan D.; Tognetti, Pedro M.; Seabloom, Eric W.; Daleo, Pedro; Power, Sally; Roscher, Christiane; Adler, Peter B.; Donohue, Ian; Wheeler, George; Stevens, Carly; Veen, G.F. Ciska; Risch, Anita C.; Wardle, Glenda M.; Hautier, Yann; Estrada, Catalina; Hersch-Green, Erika; Niu, Yujie; Peri, Pablo L.; Eskelinen, Anu; Gruner, Daniel S.; Venterink, Harry Olde; D’Antonio, Carla; Cadotte, Marc W.; Haider, Sylvia; Eisenhauer, Nico; Catford, Jane; Virtanen, Risto; Morgan, John W.; Tedder, Michelle; Bagchi, Sumanta; Caldeira, Maria C.; Bugalho, Miguel N.; Knops, Johannes M.H.; Dickman, Chris R.; Hagenah, Nicole; Jentsch, Anke; Macek, Petr; Osborne, Brooke B.; Laanisto, Lauri; Chase, Jonathan M.
Nutrient enrichment typically causes local plant diversity declines. A common but untested expectation is that nutrient enrichment also reduces variation in nutrient conditions among localities and selects for a smaller pool of species, causing greater diversity declines at larger than local scales and thus biotic homogenization. Here we apply a framework that links changes in species richness across scales to changes in the numbers of spatially restricted and widespread species for a standardized nutrient addition experiment across 72 grasslands on six continents. Overall, we find proportionally similar species loss at local and larger scales, suggesting similar declines of spatially restricted and widespread species, and no biotic homogenization after 4 years and up to 14 years of treatment. These patterns of diversity changes are generally consistent across species groups. Thus, nutrient enrichment poses threats to plant diversity, including for widespread species that are often critical for ecosystem functions.
Filling the gaps : herpetological checklist of Mayombe National Park and Cabinda Province (Angola) shed light on one of the most unexplored74 corners of tropical Central Africa
(Taylor and Francis, 2025) Lobon-Rovira, Javier; Baptista, Ninda L.; Clark, Tyron; Verburgt, Luke; Jongsma, Greg; Conradie, Werner; Verissimo, Luis; Vaz Pinto, Pedro
The global environmental crisis has reinforced the importance of improving the documentation of the geographical distributions of extant species. With this aim, species inventories of specific locations or regions are a high priority, especially so in poorly explored areas. Cabinda Province, an Angolan enclave located between the Republic of Congo and the Democratic Republic of the Congo (DRC), represents one of the most enigmatic and poorly explored areas in Africa. No detailed species inventories within its protected areas (namely, Mayombe National Park) exist. Furthermore, this region presents some of the better preserved remanent of primary moist rainforest in West Africa. Although these forests are severely threatened by logging and by the rapid social growth in the area. Therefore, we provide here the first herpetological checklist of Mayombe National Park and Cabinda Province, Angola, to shed light on this underexplored corner of Africa. To obtain the most accurate species identification, we performed detailed morphological examinations and DNA barcoding identifications. As a result, we recorded a total of 76 species of amphibians and reptiles in the area, including four new genera, 19 new distribution records for Angola, and 13 candidate species. This work also provides novel topotypic genetic material from three reptile species (i.e., Agama congica, Panaspis cabindae and Atractaspis congica), that may contribute to revise and solve taxonomic inconsistencies in these different groups. Finally, we identified areas of high species richness, as well as areas with a high number of habitat specialists, thus indicating species more vulnerable to extinction. Therefore, our study allowed us to identify areas that are of special interest for conservation of reptiles and amphibians, primarily focus on species vulnerable to extinction, but also to identify some knowledge gaps that still need further investigation. To conclude, this work not only contributes to an improved understanding of Angolan herpetofauna, but also highlights the importance of the western slope of Central Africa as an important biodiversity hotspot, centre of endemism and potential source of diversification for this group of land vertebrates.
Garbage consumption by Arctic terrestrial predators in one of the most pristine land areas on Earth
(Norsk Polarinstitutt, 2024-01) Gort-Esteve, Araceli; Abrham, Muzit; Carøe, Christian; Masviken, Johannes; Freire, Susana; Lecomte, Nicolas; Pecnerova, Patricia; Angerbjorn, Anders; Filella, Jordi Bartolome; Noren, Karin; Dalerum, Fredrik
Garbage may cause substantial environmental perturbations, in part because of its consumption by wildlife. Such consumption may have direct health implications for animals and may also influence trophic relationships. Even in pristine Arctic ecosystems, wildlife feeding in marine environments consume garbage in the form of plastic debris transported by ocean currents. We show that Arctic wildlife in pristine terrestrial environments may also ingest garbage or food items derived from abandoned camp sites. We found the remains of a chocolate wrapper and a milk powder bag in two Arctic fox (Vulpes lagopus) scats and a piece of cloth in an Arctic wolf (Canis lupus arctos) scat collected near Nares Strait, northern Greenland, one of the most pristine terrestrial wilderness regions on Earth. Found on Washington Land and associated with long-abandoned camp sites, these three scats were among 657 Arctic fox scats and 92 wolf scats collected as part of a larger study. Our study demonstrates that these two highly opportunistic predators managed to consume garbage despite the almost complete lack of human activity in this High-Arctic region. Our results highlight that abandoned anthropogenic material in the High Arctic may function as a source of garbage for local terrestrial wildlife over extended time periods, and that garbage consumption may become a potential issue if human activity in remote Arctic regions increases.
Evaluating the use of marine subsidies by Arctic foxes without direct coastal access ; insights from stable isotopes
(Springer, 2024-09) Angerbjorn, Anders; Liden, Kerstin; Roth, James D.; Dalerum, Fredrik
The trophic structures of tundra ecosystems are often viewed as a result of local terrestrial primary productivity. However, other resources can be brought in through long-distant migrants or be directly accessible in coastal areas. Hence, trophic structures may deviate from predictions based on local terrestrial resources. The Arctic fox (Vulpes lagopus) is a small canid that may use marine resources when available. We used stable isotope values in Arctic fox fur and literature data on potential prey to evaluate Arctic fox summer resource use in a mountain tundra without coastal access. The dietary contribution of local prey, presumably mostly rodents, declined with declining rodent abundance, with a subsequent increased contribution of migratory prey relying on marine resources. Stable isotope values did not differ between this terrestrial area and an area with direct coastal access during years of high rodent abundance, but isotope values during low rodent abundances suggested less marine input than in a coastal population feeding primarily on marine prey. Our study shows that marine resources may be used by animals in areas without any coastal access, and we highlight that such partial coupling of ecosystems must be included in the modeling and assessments of tundra environments.
First record of ocular albinism in sub-Antarctic fur seal (Arctocephalus tropicalis) pups on Marion Island
(Springer, 2024-02) Shihlomule, Yinhla Desmond; Weideman, Eleanor A.; Van der Vyver, J.S. Fredrik; Conry, Danielle S.; Jordaan, Rowan Keith; De Bruyn, P.J. Nico
We report on an occurrence of ocular albinism in sub-Antarctic fur seal (Arctocephalus tropicalis) pups born on Marion Island, Prince Edward Archipelago. While previous observations have documented pups with atypical lanugo pelage colorations, this is the first case involving hypopigmentation of both fur and other tissues, including the eyes and nails. During the austral summer of 2021/22, we encountered four sub-Antarctic fur seal pups displaying this anomalous pigmentation. These anomalous individuals were found along two beaches on the island’s western side and one beach on the eastern side during an island-wide fur seal census. Although the characteristics observed strongly suggest ocular albinism, confirmation would be necessary through genetic analyses. The absence of melanin in mammalian eyes is known to compromise visual acuity, which may likely result in reduced survival beyond the weaning period, explaining the paucity of such adults in this well-observed population.
4-Ethylacetophenone from potato plants repels Phthorimaea operculella and inhibits oviposition : a sustainable management strategy
(MDPI, 2025-04) Ma, Xinyu; Yan, Junjie; Su, Guangyuan; Khamis, Fathiya Mbarak; Hategekiman, Athanase; Gao, Yulin
The potato tuber moth, Phthorimaea operculella (Zeller), is an important pest of potato crops capable of boring into and consuming the potato tubers. Although chemical insecticides are employed to control P. operculella populations, their efficacy is frequently limited, raising environmental concerns. Host plant volatiles are important allelochemicals that can be exploited for the management of pests. In our previous studies, we identified five volatile organic compounds (3-ethylacetophenone, 4-ethylacetophenone, geranylacetone, ethylbenzene, and 4-hydroxy-4-methyl-2-pentanone) as allelochemicals potentially influencing the oviposition behavior of P. operculella. Using electroantennography (EAG) and behavioral assays, we found that 4-ethylacetophenone significantly repelled P. operculella at all tested concentrations (1 μg, 10 μg, and 100 μg; p < 0.05), while 3-ethylacetophenone showed no significant effects (p > 0.05). Finally, the effect of 4-ethylacetophenone on preventing P. operculella from laying eggs was determined by an oviposition selection experiment. Our findings indicate that 4-ethylacetophenone derived from potato plants not only repels P. operculella and prevents egg-laying but also has the potential to reduce the number of eggs, making it a promising green alternative for controlling this pest.
Forb diversity globally is harmed by nutrient enrichment but can be rescued by large mammalian herbivory
(Nature Research, 2025-03) Nelson, Rebecca A.; Sullivan, Lauren L.; Hersch-Green, Erika I.; Seabloom, Eric W.; Borer, Elizabeth T.; Tognetti, Pedro M.; Adler, Peter B.; Biederman, Lori; Bugalho, Miguel N.; Caldeira, Maria C.; Cancela, Juan P.; Carvalheiro, Luísa G.; Catford, Jane A.; Dickman, Chris R.; Dolezal, Aleksandra J.; Donohue, Ian; Ebeling, Anne; Eisenhauer, Nico; Elgersma, Kenneth J.; Eskelinen, Anu; Estrada, Catalina; Garbowski, Magda; Graff, Pamela; Gruner, Daniel S.; Hagenah, Nicole; Haider, Sylvia; Harpole, W. Stanley; Hautier, Yann; Jentsch, Anke; Johanson, Nicolina; Koerner, Sally E.; Lannes, Lucíola S.; Macdougall, Andrew S.; Martinson, Holly; Morgan, John W.; Olde Venterink, Harry; Orr, Devyn; Osborne, Brooke B.; Peri, Pablo L.; Power, Sally A.; Raynaud, Xavier; Risch, Anita C.; Shrestha, Mani; Smith, Nicholas G.; Stevens, Carly J.; Veen, G.F. Ciska; Virtanen, Risto; Wardle, Glenda M.; Wolf, Amelia A.; Young, Alyssa L.; Harrison, Susan P.
Forbs (“wildflowers”) are important contributors to grassland biodiversity but are vulnerable to environmental changes. In a factorial experiment at 94 sites on 6 continents, we test the global generality of several broad predictions: (1) Forb cover and richness decline under nutrient enrichment, particularly nitrogen enrichment. (2) Forb cover and richness increase under herbivory by large mammals. (3) Forb richness and cover are less affected by nutrient enrichment and herbivory in more arid climates, because water limitation reduces the impacts of competition with grasses. (4) Forb families will respond differently to nutrient enrichment and mammalian herbivory due to differences in nutrient requirements. We find strong evidence for the first, partial support for the second, no support for the third, and support for the fourth prediction. Our results underscore that anthropogenic nitrogen addition is a major threat to grassland forbs, but grazing under high herbivore intensity can offset these nutrient effects.
Interactive and unimodal relationships between plant biomass, abiotic factors, and plant diversity in global grasslands
(Nature Research, 2025-01) Spohn, Marie; Bagchi, Sumanta; Bakker, Jonathan D.; Borer, Elizabeth T.; Carbutt, Clinton; Catford, Jane A.; Dickman, Christopher R.; Eisenhauer, Nico; Eskelinen, Anu; Hagenah, Nicole; Hautier, Yann; Koerner, Sally E.; Komatsu, Kimberly J.; Laanisto, Lauri; Lekberg, Ylva; Martina, Jason P.; Martinson, Holly; Partel, Meelis; Peri, Pablo L.; Risch, Anita C.; Smith, Nicholas G.; Stevens, Carly; Veen, G.F. Ciska; Virtanen, Risto; Yahdjian, Laura; Young, Alyssa L.; Young, Hillary S.; Seabloom, Eric W.
Grasslands cover approximately a third of the Earth’s land surface and account for about a third of terrestrial carbon storage. Yet, we lack strong predictive models of grassland plant biomass, the primary source of carbon in grasslands. This lack of predictive ability may arise from the assumption of linear relationships between plant biomass and the environment and an underestimation of interactions of environmental variables. Using data from 116 grasslands on six continents, we show unimodal relationships between plant biomass and ecosystem characteristics, such as mean annual precipitation and soil nitrogen. Further, we found that soil nitrogen and plant diversity interacted in their relationships with plant biomass, such that plant diversity and biomass were positively related at low levels of nitrogen and negatively at elevated levels of nitrogen. Our results show that it is critical to account for the interactive and unimodal relationships between plant biomass and several environmental variables to accurately include plant biomass in global vegetation and carbon models.
Exploring the microbiomes of camel ticks to infer vector competence : insights from tissue-level symbiont-pathogen relationships
(Scientific Reports, 2025-02) Khogali, Rua; Bastos, Armanda D.S.; Getange, Dennis; Bargul, Joel L.; Kalayou, Shewit; Ongeso, Nehemiah; Verhoeven, Joost Theo Petra; Kabii, James; Ngiela, John; Masiga, Daniel; Villinger, Jandouwe
Ticks are blood-feeding ectoparasites that harbor diverse pathogens and endosymbionts. Their microbial communities vary based on tick species, stage, sex, geographical location, surrounding environment, and tissue type. Understanding tick microbiota at the tissue level is crucial for unraveling how microbiomes are distributed in tick tissues and influence pathogen transmission. We used V1-V2 16 S rRNA gene sequencing to analyze tissue-specific bacterial compositions (hemolymph, saliva, salivary glands, and midgut) of Amblyomma gemma, Rhipicephalus pulchellus, Hyalomma dromedarii, and Hyalomma rufipes ticks collected from camels in Marsabit County, northern Kenya. The V1-V2 region of the 16 S rRNA gene effectively differentiated 43 Rickettsia africae and 16 Rickettsia aeschlimannii tick samples from other rickettsial species, as well as Coxiella endosymbionts from Coxiella burnetii. In contrast, the V3-V4 region sequences of these species could not be clearly distinguished. Coxiella endosymbionts were most common in Am. gemma and Rh. pulchellus, while Francisella endosymbionts predominated in Hyalomma ticks; both were primarily localized in the salivary glands. High abundances of Coxiella endosymbionts, as well as Pseudomonas, were associated with the absence or low abundance of Rickettsia pathogens in both Am. gemma and Rh. pulchellus, suggesting competitive interactions between these microbes. Additionally, Proteus mirabilis, an opportunistic pathogen of the urinary tract in humans, was found predominantly in Hyalomma ticks, except for the salivary glands, which were most abundant with Francisella endosymbionts. Furthermore, we detected the Acinetobacter, Pseudomonas, and Corynebacterium genera in all the tick tissues, supporting the hypothesis that these bacteria might circulate between camel blood and ticks. Saliva and hemolymph generally harbored more extracellular bacteria than the salivary glands and midgut. This study provides a new approach to unravel tick-endosymbiont-pathogen interactions by examining the tissue localization of tick-borne pathogens and symbionts in Am. gemma, Rh. pulchellus, Hy. dromedarii, and Hy. rufipes from camels in northern Kenya. Our findings establish a baseline for developing an understanding of the functional capacities of symbionts and for designing symbiont-based control strategies.
Frequent failure of nutrients to increase plant biomass supports the need for precision fertilization in agriculture
(Nature Research, 2025-04) Carroll, Oliver H.; Seabloom, Eric W.; Borer, Elizabeth T.; Harpole, W. Stanley; Wilfahrt, Peter; Arnillas, Carlos A.; Bakker, Jonathan D.; Blumenthal, Dana M.; Boughton, Elizabeth; Bugalho, Miguel N.; Caldeira, Maria; Campbell, Malcolm M.; Catford, Jane; Chen, Qingqing; Dickman, Christopher R.; Donohue, Ian; DuPre, Mary Ellyn; Eskelinen, Anu; Estrada, Catalina; Fay, Philip A.; Fraser, Evan D.G.; Hagenah, Nicole; Hautier, Yann; Hersh-Green, Erika; Jonsdottir, Ingibjoerg S.; Kadoya, Taku; Komatsu, Kimberly; Lannes, Luciola; Liang, Maowei; Venterink, Harry Olde; Peri, Pablo; Power, Sally A.; Price, Jodi N.; Ren, Zhengwei; Risch, Anita C.; Sonnier, Gregory; Veen, G.F.; Virtanen, Risto; Wardle, Glenda M.; Waring, Elizabeth F.; Wheeler, George; Yahdjian, Laura; Macdougall, Andrew S.
Implementing precision fertilization to maximize crop yield while minimizing economic and environmental impacts has become critical for agriculture. Variability in biomass response to fertilization within fields, among regions, and over time creates simultaneous risks of under-yielding and overfertilization. We quantify factors determining fertilization responsiveness (i.e., biomass increases with fertilization) up to 15 years in 61 unfertilized rangelands on six continents. We demonstrate widespread multi-year variability in responsiveness, with fertilization increasing average yield by 43% but failing to improve biomass 26% of the time. All sites were responsive at least once, but only four of 61 responded in all plots and years. Modelled management scenarios highlighted that fertilizer cessation is likely to generate sizable economic savings but always reduces yield because of the difficulty in predicting when and where biomass will be unresponsive. This work reveals substantial scale-dependent variability in fertilization responsiveness globally, while clarifying the prospects and pitfalls of managing more spatially and temporally precise nutrient application.
Nanosilica supplementation in tomato increases oviposition on stems and caterpillar mortality in the tomato pinworm
(National Academy of Sciences, 2025-04) Fiaboe, Kokou Rodrigue; Khamis, Fathiya Mbarak; Yusuf, Abdullahi Ahmed; Torto, Baldwyn
Silicon-induced responses play a key role in plant defense against herbivory, though the underlying mechanisms remain underexplored. In this study, we examined how mesoporous silica nanoparticles (MSNs) affect tomato (Solanum lycopersicum) defense against an invasive and highly destructive lepidopteran herbivore, the tomato pinworm (TPW), Phthorimaea absoluta. In tomato plants supplemented with MSN, prior exposure to TPW oviposition shifted subsequent egg-laying from a preference for leaves to an even distribution between stems and leaves. This shift was not observed in nonsilicon-supplemented plants. Prolonged oviposition triggered pigmentation in the basal cells of type I glandular trichomes on the stems of silicon-supplemented plants. Chemical analysis by coupled gas chromatography-mass spectrometry revealed that the pigmented trichome was rich in soluble sugars (sucrose and l-arabinose) and waxes, dominated by the saturated hydrocarbon tetracosane. Bioassays with the crude extract of the pigmented trichome and a three-component sugar–wax blend replicated the oviposition and caterpillar response observed with the pigmented trichome, while individual components produced variable effects. While l-arabinose alone replicated the oviposition effects of the three-component sugar–wax blend, sucrose increased oviposition and caterpillar feeding and survival, while l-arabinose and tetracosane caused the highest caterpillar mortality. Additionally, these treatments altered caterpillar gut microbiota composition and influenced frass volatiles, which attracted the TPW natural enemies, Nesidiocoris tenuis (predator) and Neochrysocharis formosa (parasitoid). Our findings suggest that silicon supplementation increases tomato defense against TPW through oviposition-induced responses, which promotes recruitment of natural enemies. SIGNIFICANCE : Plants utilize physical and biochemical defenses to protect themselves from herbivores, yet the role of nonnutritional components like mesoporous silica nanoparticles (MSNs) in plant–herbivore interactions is not well understood. In this study, we explored silicon-mediated defenses in tomato plants against the tomato pinworm (TPW), a major agricultural pest. Supplementation with MSNs enhanced biochemical defenses in tomato trichomes, a key site of plant–herbivore interaction. TPW females are attracted to MSN-enriched trichomes for egg-laying on stems, but caterpillars that hatch and consume the trichomes experience high mortality, reducing pest survival and minimizing plant damage. Additionally, silicon supplementation indirectly strengthens plant defenses by altering volatile organic compound (VOC) emissions in caterpillar frass, which attract the TPW natural enemies Nesidiocoris tenuis (predator) and Neochrysocharis formosa (parasitoid). These results suggest that MSN supplementation could be an effective crop protection strategy, enhancing plant resilience and promoting the recruitment of natural enemies.
Bacterial blood microbiome of Mastomys rodents : implications for disease spill-over at the animal-human interface within the Bushbuckridge-East community, South Africa
(Frontiers Media, 2025-02) Kolo, Agatha Onyemowo; Brayton, Kelly A.; Collins, Nicola E.; Bastos, Armanda D.S.; Matthee, Sonja; Gall, Cory A.; Wentzel, Jeanette Maria; Neves, L.C.B.G.D. (Luís); Oosthuizen, Marinda C.
The Bushbuckridge-East community in Mpumalanga Province, South Africa is bordered by nature reserves, including the Manyeleti Game Reserve. Murid rodents are prevalent in both Manyeleti and communal rangelands adjoining the community households. Although rodents are reservoir hosts for a broad range of viral, bacterial and parasitic pathogens, the rodent microbial diversity and transmission of zoonotic agents to humans in the community is understudied. In this study we investigated bacterial diversity in wild and commensal rodents sampled from different habitats. The 16S rRNA gene was amplified from DNA extracted from the blood of 24 wild Mastomys and one Steatomys sp. and subjected to PacBio circular consensus sequencing. As Bartonella species were dominant in the blood microbiome, gltA gene characterization was performed to delineate species. Rodents sampled from peri-urban and communal rangelands had higher proportions of Bartonella spp. [Hlalakahle (77.7%), Gottenburg (47.8%), Tlhavekisa (83.8%)] compared to those from the protected habitat (43.8%). Ehrlichia spp., Anaplasma spp., and Coxiella burnetii were detected at <1% of the sequence reads. Conventional PCR and sequencing validated the detection of Bartonella spp. with the first confirmation of Bartonella mastomydis infection in Mastomys in South Africa. Additionally, 317 mites, 90 fleas, 10 ticks and eight lice were collected from the rodents, providing evidence of possible vectors of the organisms detected. The detection of zoonotic agents in rodents in Bushbuckridge-East community, together with prior serological confirmation of Bartonella and Coxiella in non-malarial acute febrile patients from this community, highlights the possible risks that commensal rodents pose to human health.
Widening global variability in grassland biomass since the 1980s
(Nature Research, 2024-10) MacDougall, Andrew S.; Esch, Ellen; Chen, Qingqing; Carroll, Oliver; Bonner, Colin; Ohlert, Timothy; Siewert, Matthias; Sulik, John; Schweiger, Anna; Borer, Elizabeth T.; Naidu, Dilip; Bagchi, Sumanta; Hautier, Yann; Wilfahrt, Peter; Larson, Keith; Olofsson, Johan; Cleland, Elsa; Muthukrishnan, Ranjan; O'Halloran, Lydia; Alberti, Juan; Anderson, T. Michael; Arnillas, Carlos A.; Bakker, Jonathan D.; Barrio, Isabel C.; Biederman, Lori; Boughton, Elizabeth H.; Brudvig, Lars A.; Bruschetti, Martin; Buckley, Yvonne; Bugalho, Miguel N.; Cadotte, Marc W.; Caldeira, Maria C.; Catford, Jane A.; D'Antonio, Carla; Davies, Kendi; Daleo, Pedro; Dickman, Christopher R.; Donohue, Ian; Dupre, Mary Ellyn; Elgersma, Kenneth; Eisenhauer, Nico; Eskelinen, Anu; Estrada, Catalina; Fay, Philip A.; Feng, Yanhao; Gruner, Daniel S.; Hagenah, Nicole; Haider, Sylvia; Harpole, W. Stanley; Hersch-Green, Erika; Jentsch, Anke; Kirkman, Kevin; Knops, Johannes M.H.; Laanisto, Lauri; Lannes, Luciola S.; Laungani, Ramesh; Lkhagva, Ariuntsetseg; Macek, Petr; Martina, Jason P.; Mcculley, Rebecca L.; Melbourne, Brett; Mitchell, Rachel; Moore, Joslin L.; Morgan, John W.; Muraina, Taofeek O.; Niu, Yujie; Paertel, Meelis; Peri, Pablo L.; Power, Sally A.; Price, Jodi N.; Prober, Suzanne M.; Ren, Zhengwei; Risch, Anita C.; Smith, Nicholas G.; Sonnier, Gregory; Standish, Rachel J.; Stevens, Carly J.; Tedder, Michelle; Tognetti, Pedro; Veen, G.F. (Ciska); Virtanen, Risto; Wardle, Glenda M.; Waring, Elizabeth; Wolf, Amelia A.; Yahdjian, Laura; Seabloom, Eric W.
Global change is associated with variable shifts in the annual production of aboveground plant biomass, suggesting localized sensitivities with unclear causal origins. Combining remotely sensed normalized difference vegetation index data since the 1980s with contemporary field data from 84 grasslands on 6 continents, we show a widening divergence in site-level biomass ranging from +51% to −34% globally. Biomass generally increased in warmer, wetter and species-rich sites with longer growing seasons and declined in species-poor arid areas. Phenological changes were widespread, revealing substantive transitions in grassland seasonal cycling. Grazing, nitrogen deposition and plant invasion were prevalent in some regions but did not predict overall trends. Grasslands are undergoing sizable changes in production, with implications for food security, biodiversity and carbon storage especially in arid regions where declines are accelerating.

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