The regular variations of light in the natural light cycle serve as one of the most important cues for the timing of biological events in organisms. The increasing prevalence of artificial light at night (ALAN) alters the natural light cycle and has been found to have harmful effects on human, wildlife, and environmental health. Although several techniques can be employed to measure ALAN, most cannot measure spectral information and, therefore, quantifying ALAN for ecological applications remains a challenge. Here we use the newly described environmental light field (ELF) method to characterise the artificial light environment inside and immediately outside houses in rural settlements (South Africa, Mozambique, and Uganda) as the lighting present in these areas will likely play a role in affecting people's risk of being infected by vector-borne diseases. The ELF method characterises the light detected by the animal retina, and so offers a powerful tool to compare artificial lighting conditions detected by organisms, taking environmental influences into account. We found light-emitting diode (LED) lighting to be the dominant lighting type across our study sites. We recorded large variability in both the intensity and spectral composition among houses, with different structural properties and light types present. Given its importance as a disease vector, we use a case study of anopheline mosquitoes, several of which act as malaria vectors, and compare how light characteristics influencing key mosquito behaviours differ among regions and houses. Houses with lights that emit higher proportions of blue and UV light may attract more of certain anopheline species, while repelling others. Higher light intensities inside houses may attract more anophelines, but reduce their feeding. How changes in mosquito attraction and feeding translate into changes in real-world communities and disease transmission, however, remains unknown.

Termites build two kinds of above-ground biogenic structures: mounds and sheeting. Sheeting is constructed to protect foraging termites against desiccation and predation while they consume the organic material that the sheeting covers. The movement of soils by termites profoundly affects soil turnover rates and modifies the patterns of water and chemical movement in soils. Despite this, the characteristics and dynamics of soil sheeting are not yet well understood. Within a broadleaf mesic (650 mm p.a.) South African savanna, we found that the fungus-growing genus Odontotermes dominated both horizontal and vertical sheeting production. In terms of quantity, there were approximately two tonnes of soil sheeting per hectare present across both the soil surface and the trees of the mesic savanna at each survey time. We found that horizontal sheeting is produced year-round while vertical sheeting is more frequent in dry seasons and in dry years. Termites are selective builders: the physical and chemical composition of horizontal and vertical sheeting differed from each other and from the matrix soils. Termites select medium-sized sand particles, silt and clay particles for the construction of horizontal sheeting and small sand particles for the construction of vertical sheeting. Horizontal sheetings was significantly enriched in nitrogen, sodium and phosphorus, while vertical sheetings was enriched in nitrogen. In savannas, primary production is strongly limited by nitrogen. These nutrient differences likely give rise to the creation of nutrient rich patches, on a finer scale than those created by termite mounds, with potentially important consequences for savanna spatial dynamics.

Savanna systems are among the most sensitive to future climate and land-use change, yet we lack robust, direct quantifications of savanna carbon cycling. Together with fire, decomposition is the main process by which the carbon and nutrients are recycled and made available again to plants. Decomposition is largely mediated by microbes and soil invertebrates. Using a novel large-scale termite suppression experiment, we quantify, for the first time, the relative contribution of microbes, termites, and other invertebrates to the decomposition of wood (fresh native and dry non-native), dry dung, and grass in a mesic savanna. We found that termites were responsible for two thirds of the mass loss from dry wood and a third of the mass loss from fresh native wood, dry dung, and dry grass. Microbes were wholly responsible for the difference as there was no evidence of other invertebrates contributing to decomposition, even with fresh wood. Using multiple substrates in savanna decomposition studies is important where a mixture of contrasting life forms occur because both the rates of decomposition and the dominant agent varied considerably. In addition, including both a dry non-native and fresh native wood cast light on possible explanatory variables such as wood density, green-ness and the presence of bark, and the necessity of teasing these variables apart in future studies. Termites stand apart from all other insects in their impact on decomposition within savannas and should be acknowledged alongside microbes and fire as the primary agents of wood, grass, and dry dung turnover in global carbon models. Savanna ecosystems are highly vulnerable to climate and land-use changes yet lack precise assessments of carbon cycling. In a large-scale termite suppression experiment, we found that termites accounted for two thirds of the mass loss from dry wood and a third of the mass loss from fresh native wood, dry dung, and dry grass. Understanding the precise contributions of termites, microbes, and fire is crucial for accurate global carbon models in savanna ecosystems.image

Functional redundancy, the potential for the functional role of one species to be fulfilled by another, is a key determinant of ecosystem viability. Scavenging transfers huge amount of energy through ecosystems and is, therefore, crucial for ecosystem viability and healthy ecosystem functioning. Despite this, relatively few studies have examined functional redundancy in scavenger communities. Moreover, the results of these studies are mixed and confined to a very limited range of habitat types and taxonomic groups. This study attempts to address this knowledge gap by conducting a field experiment in an undisturbed natural environment assessing functional roles and redundancy in vertebrate and invertebrate scavenging communities in a South African savanna. We used a large-scale field experiment to suppress ants in four 1 ha plots in a South African savanna and paired each with a control plot. We distributed three types of small food bait: carbohydrate, protein and seed, across the plots and excluded vertebrates from half the baits using cages. Using this combination of ant suppression and vertebrate exclusion, allowed us explore the contribution of non-ant invertebrates, ants and vertebrates in scavenging and also to determine whether either ants or vertebrates were able to compensate for the loss of one another. In this study, we found the invertebrate community carried out a larger proportion of overall scavenging services than vertebrates. Moreover, although scavenging was reduced when either invertebrates or vertebrates were absent, the presence of invertebrates better mitigated the functional loss of vertebrates than did the presence of vertebrates against the functional loss of invertebrates. There is a commonly held assumption that the functional role of vertebrate scavengers exceeds that of invertebrate scavengers; our results suggest that this is not true for small scavenging resources. Our study highlights the importance of invertebrates for securing healthy ecosystem functioning both now and into the future. We also build upon many previous studies which show that ants can have particularly large effects on ecosystem functioning. Importantly, our study suggests that scavenging in some ecosystems may be partly resilient to changes in the scavenging community, due to the potential for functional compensation by vertebrates and ants. This is a large-scale, factorial study which is the first of its kind to demonstrate the capacity for functional compensation amongst scavenger guilds in African savannas. We suggest that scavenging in some ecosystems may be partially resilient to changes in scavenging communities, due to functional compensation by vertebrates and ants.image

The risk of new establishments of Queensland fruit fly (Qfly), Bactrocera tryoni, in pest-free areas is linked to the fruit carried by road travellers. However, there is little information on what proportion of carried fruit is infested. Previous studies examined the numbers of fruits carried by travellers but not if the fruits were infested. Here, we report on the results of 989 fruit consignments seized on three main entry roads into the Fruit Fly Exclusion Zone and assessed for infestation. We found 1.01% of consignments were infested with tephritids. However, only 0.2% were infested with sufficient Qfly to potentially result in a new establishment. Within the main fruit groups carried, we detected stone fruit, tomatoes, pome fruit, citrus, bananas and tropical fruit in that order. Based on our data and previously published figures, we estimated that there were 1148 consignments infested with tephritids that entered the zone annually. Additionally, we estimated that 227 vehicles carried Qfly-infested fruit consignments into the quarantine zone annually and each of these had the potential to start a new establishment. Our results will help inform managers of quarantine zones.

ABSTRACTAimTermites are a crucial group of macroinvertebrates regulating rates of deadwood decomposition across tropical and subtropical regions. When examining global patterns of deadwood decay, termites are treated as a homogenous group. There exist key biogeographical differences in termite distribution. One such clear distinction is the distribution of fungus‐growing termites (FGT, subfamily Macrotermitinae). Considering that climate will have shaped termite distribution and ecosystem processes, we evaluate the roles of termite distribution (presence of FGT) and climate (aridity) on global patterns in deadwood decay.LocationBetween 46° N‐43° S and 175° E‐85° W.Time PeriodPresent (between 2016 and 2021).Major Taxa StudiedTermites (Blattodea: Termitoidae).MethodsWe add salient data to an existing global dataset on deadwood decomposition, including new data from five existing sites and seven additional African sites. We analyse a dataset spanning six continents, 16 countries and 102 experimental sites. Firstly, we evaluate climatic differences (mean annual temperature, mean annual precipitation and mean annual aridity) between sites with and without FGT. Secondly, using aridity as a single comparative climate metric between sites that accounts for temperature and precipitation differences, we examine the interaction between FGT and aridity on global patterns of termite deadwood discovery and decay through multivariate logistic and linear regressions.ResultsTermite‐driven decay and wood discovery increased with aridity; however, responses differed between FGT and NFGT sites. Wood discovery increased with aridity in FGT sites only, suggesting a greater role of FGT to deadwood decay in arid environments. On average, both termite discovery and decay of deadwood were approximately four times greater in regions with FGT compared with regions without FGT.Main ConclusionsTermite discovery and decay of deadwood is climate dependent, and higher decay may be through greater discovery of deadwood in FGT sites. Inclusion of biogeographical differences in termite distribution could potentially alter current and future global estimates of deadwood turnover.

Termite mounds are keystone structures in African savannas, affecting multiple ecosystem processes. Despite the large size of termite mounds having the potential to modify conditions around them, patterns of mound-induced ecosystem effects have been assumed to be isotropic, with little attention given to how effects might vary around mounds. We measured soil nitrogen content, grass species composition, and mammalian grazing on and off termite mounds in the four cardinal directions, and across wet and dry seasons at three savanna sites varying in mean annual rainfall in South Africa's Kruger National Park. Evidence of directional effects (anisotropy) on ecosystem properties around termite mounds varied with site. Grass species composition differed between north- and south-facing slopes at the two drier sites where mounds were taller. However, differences in grazing extent and soil nitrogen content around mounds were only present at the intermediate rainfall site where mammalian herbivore biomass was highest, and mounds were of medium height. Our results suggest that termite mound effects display significant variation with direction, but that the emergence of directional effects is context dependent. Our results further suggest that such context-dependent directional effects can lead to positive feedback loops between termites, abiotic conditions, and mammalian herbivores.

Five myrmecophagous mammal species occur sympatrically over large parts of southern Africa. Of these, the diets of four species have been studied in sufficient detail to facilitate interspecific comparisons. The diets of the aardvark Orycteropus afer, aardwolf Proteles cristatus, bat-eared fox Otocyon megalotis and Temminck’s pangolin Smutsia temminckii were compared based on the overall prey categories utilised and the proportion of each prey category in their diets, while Meller’s mongoose Rhynchogale melleri had too few data to be assessed. Bat-eared fox fed on the greatest number of prey categories (n = 116) and had the greatest dietary niche breadth (4.71), while aardwolf utilised the fewest prey categories (n = 28) and had the lowest dietary niche breadth (1.19) when analysing the proportion of each prey category in the diet at the genus level. Temminck’s pangolin was the only species that was observed to feed exclusively on ants and termites. The diets of Temminck’s pangolin and aardvark showed a moderate degree of overlap (dietary niche breadth 0.49–0.57), but overlap was low between all other species pairs (0.01–0.26) when analysing the proportion of each prey item in the diet at the genus level. The results suggest that these myrmecophages have low to moderate dietary overlap, which combined with the high abundance of ants and termites and differences in their feeding ecologies, likely reduces interspecific competition.

We show that dansylcadaverine (1) a known in-cell inhibitor of clathrin mediated endocytosis (CME), moderately inhibits dynamin I (dynI) GTPase activity (IC50 45 μM) and transferrin (Tfn) endocytosis in U2OS cells (IC50 205 μM). Synthesis gave a new class of GTP-competitive dynamin inhibitors, the Sulfonadyns™. The introduction of a terminal cinnamyl moiety greatly enhanced dynI inhibition. Rigid diamine or amide links between the dansyl and cinnamyl moieties were detrimental to dynI inhibition. Compounds with in vitro inhibition of dynI activity <10 μM were tested in-cell for inhibition of CME. These data unveiled a number of compounds, e.g. analogues 33 ((E)-N-(6-{[(3-(4-bromophenyl)-2-propen-1-yl]amino}hexyl)-5-isoquinolinesulfonamide)) and 47 ((E)-N-(3-{[3-(4-bromophenyl)-2-propen-1-yl]amino}propyl)-1-naphthalenesulfonamide)isomers that showed dyn IC50 <4 μM, IC50(CME) <30 μM and IC50(SVE) from 12-265 μM. Both analogues (33 and 47) are at least 10 times more potent that the initial lead, dansylcadaverine (1). Enzyme kinetics revealed these sulfonamide analogues as being GTP competitive inhibitors of dynI. Sulfonadyn-47, the most potent SVE inhibitor observed (IC50(SVE) = 12.3 μM), significantly increased seizure threshold in a 6 Hz mouse psychomotor seizure test at 30 (p = 0.003) and 100 mg kg-1 ip (p < 0.0001), with similar anti-seizure efficacy to the established anti-seizure medication, sodium valproate (400 mg kg-1). The Sulfonadyn™ class of drugs target dynamin and show promise as novel leads for future anti-seizure medications.

Abstract Decomposition is the process by which dead plant biomass is recycled and made available again for uptake by other plants. It is largely mediated by microbes and soil invertebrates. Global decomposition studies have demonstrated that decomposition is primarily temperature-driven with rainfall playing a secondary role, although to date, all global decomposition studies have used a single substrate to measure decomposition meaning differences with substrate type may be missed. Here we explored the decomposition of wood, dung and grass along a rainfall gradient (380–650 mm/year) at three savanna sites in South Africa. As the three sites experience a similar temperature range, we effectively controlled for temperature allowing us to explore the effect of rainfall in isolation. We used decomposition bags - with and without termite access - and measured mass loss after set time intervals. We predicted that the absolute decomposition of all three substrates would increase along the rainfall gradient. This assumption held for dung and grass, but we found the reverse for wood. Our study highlights the importance of considering multiple substrates as decomposition patterns and dominant agents can vary. Unexpectedly low wood decomposition at our wettest site suggests that the amount of dead wood available, and therefore probability of discovery by termites, may be an important factor explaining findings from decomposition studies. Resource availability and termite discovery is a neglected subject within decomposition studies and warrants further investigation.

Native-alien population is defined as a population that is within a country to which the species is native and founded by individuals moved by direct human agency (or substantial indirect human agency) over a biogeographical barrier to an area beyond the species’ native range (Nelufule et al. 2022).Reference Nelufule T, Robertson MP, Wilson JRU, Faulkner KT (2022) Native-alien populations—an apparent oxymoron that requires specific conservation attention. NeoBiota 74: 57–74, https://doi.org/10.3897/neobiota.74.81671

There is burgeoning interest in how artificial light at night (ALAN) interacts with disease vectors, particularly mosquitoes. ALAN can alter mosquito behaviour and biting propensity, and so must alter disease transfer rates. However, most studies to date have been laboratory-based, and it remains unclear how ALAN modulates disease vector risk. Here, we identify five priorities to assess how artificial light can influence disease vectors in socio-ecological systems. These are to (i) clarify the mechanistic role of artificial light on mosquitoes, (ii) determine how ALAN interacts with other drivers of global change to influence vector disease dynamics across species, (iii) determine how ALAN interacts with other vector suppression strategies, (iv) measure and quantify the impact of ALAN at scales relevant for vectors, and (v) overcome the political and social barriers in implementing it as a novel vector suppression strategy. These priorities must be addressed to evaluate the costs and benefits of employing appropriate ALAN regimes in complex socio-ecological systems if it is to reduce disease burdens, especially in the developing world.This article is part of the theme issue 'Light pollution in complex ecological systems'.

Species can be both native and alien to a given administrative region. Here we present the first consolidated inventory of these ‘native-alien populations’ for South Africa, and provide an overview of the data it contains. To gather data, literature searches were performed and experts were consulted both directly and via an on-line survey. Putative native-alien populations were then scored based on a newly developed protocol. The final inventory contains information on 77 native species from 49 families across nine classes that have formed 132 native-alien populations across the terrestrial, freshwater, and marine environments. The phenomenon is rare when compared to the prevalence of related phenomena, such as alien species introduced from other countries (2033 alien species in South Africa), but is under-reported. However, they pose a specific problem for regulators and managers and their importance will likely increase with global change. These data will be integrated with an existing alien species list and, we hope, will provide a useful foundation to address the issue. We encourage those working on biodiversity to contribute more records.

It is important for regulators and managers to effectively distinguish native from alien taxa.However, a taxon can have both native and alien populations within the same country as biogeographic and administrative boundaries do not always align.Here we propose a protocol for classifying populations as native, alien, cryptogenic, or native-alien, and describe the evidence required.This protocol comprises of three questions: (1) is the population outside the historic native range of the taxon, (2) is/was natural dispersal from the native range unlikely, and (3) is the taxon native to a part of the administrative region where the population is found.If information on introduction pathways, genetics, and biogeographical barriers is available, we propose an alternative process to answer question 2. The protocol was applied to 176 suspected native-alien populations in South Africa.A total of 132 populations from 77 native taxa were classified as native-alien, 13 as cryptogenic, 13 as alien (native-alien status uncertain), and 18 as native.We believe the protocol provides a transparent and standardised method for categorising native-alien populations and thereby facilitates the appropriate regulation and management of this type of biological invasion.

Methyl oleate, an example of a FAME (fatty acid methyl ester), was produced by oleic acid (OA) photoesterification with TO, and UVA light. Different parameters were evaluated and optimised: catalyst pretreatment, temperature (25-65 degrees C), catalyst loading (1-30% w/w(OA)) and oleic acid:alcohol molar ratio (1:3-1:55). Response surface quadratic methodology obtained by central composite rotational design (RSM-CCRD) was used to evaluate the main operational conditions of the photoesterification process. A high conversion of 98% (+/- 0.8) at 55 degrees C, 20% TiO2 (w/w(OA)), and 1(OA):55(methanol) molar ratio was achieved. The photoesterification mechanism is furthermore proposed. The Langmuir-Hinshelwood kinetic model considered the forward and backward reaction as first-order fits with the best accuracy (R-2 of 0.997). The thermodynamic results (Delta G(338.15K)=-20.75 kJ/mol, Delta H=13.75 kJ/mol, and Delta S=0.47 kJ/mol.K) indicate that the operating conditions are important, both to supply the energy requirement of the reaction, but also to increase the miscibility of the reactants.

Deadwood is a large global carbon store with its store size partially determined by biotic decay. Microbial wood decay rates are known to respond to changing temperature and precipitation. Termites are also important decomposers in the tropics but are less well studied. An understanding of their climate sensitivities is needed to estimate climate change effects on wood carbon pools. Using data from 133 sites spanning six continents, we found that termite wood discovery and consumption were highly sensitive to temperature (with decay increasing >6.8 times per 10°C increase in temperature)-even more so than microbes. Termite decay effects were greatest in tropical seasonal forests, tropical savannas, and subtropical deserts. With tropicalization (i.e., warming shifts to tropical climates), termite wood decay will likely increase as termites access more of Earth's surface.

Animals, such as termites, have largely been overlooked as global-scale drivers of biogeochemical cycles 1,2 , despite site-specific findings 3,4 . Deadwood turnover, an important component of the carbon cycle, is driven by multiple decay agents. Studies have focused on temperate systems 5,6 , where microbes dominate decay 7 . Microbial decay is sensitive to temperature, typically doubling per 10°C increase (decay effective Q 10 = ~2) 8–10 . Termites are important decayers in tropical systems 3,11–13 and differ from microbes in their population dynamics, dispersal, and substrate discovery 14–16 , meaning their climate sensitivities also differ. Using a network of 133 sites spanning 6 continents, we report the first global field-based quantification of temperature and precipitation sensitivities for termites and microbes, providing novel understandings of their response to changing climates. Temperature sensitivity of microbial decay was within previous estimates. Termite discovery and consumption were both much more sensitive to temperature (decay effective Q 10 = 6.53), leading to striking differences in deadwood turnover in areas with and without termites. Termite impacts were greatest in tropical seasonal forests and savannas and subtropical deserts. With tropicalization 17 (i.e., warming shifts to a tropical climate), the termite contribution to global wood decay will increase as more of the earth’s surface becomes accessible to termites.

Many countries define nativity at a country-level—taxa are categorised as either alien species or native species. However, there are often substantial within-country biogeographical barriers and so a taxon can be native and alien to different parts of the same country. Here, we use the term ‘native-alien populations’ as a short-hand for populations that result from the human-mediated dispersal of individuals of a species beyond a biogeographical barrier to a point beyond that species’ native range, but that is still within the same political entity as parts of the species’ native range. Based on these criteria, we consider native-alien populations to be biological invasions. However, we argue that, in comparison to other alien populations, native-alien populations: 1) are likely to be closer geographically to their native range; 2) are likely to be phylogenetically and ecologically more similar to native species in their introduced range; and 3) options to control their introduction or manage them will likely be more limited. We argue this means native-alien populations tend to differ from other alien populations in the likelihood of invasion, the types of impacts they have, and in how they can be most effectively managed. We also argue that native-alien populations are similarly a distinct phenomenon from native populations that are increasing in abundance or range extent. And note that native-alien populations are expected to be particularly common in large, ecologically diverse countries with disjunct biomes and ecoregions. Reporting, monitoring, regulating and managing native-alien populations will, we believe, become an increasingly important component of managing global change.

Datasets and R scripts for the above article.