Marcus J Byrne

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• PhD
• Professor (Emeritus) at University of the Witwatersrand

Water plays significant role in an aquatic ecosystem, and it displays its own biotic and abiotic characteristics that indicate the status of the ecosystem. Thus, it is crucial to assess and monitor the quality of water to ensure that it remains functional. Field-based methods are used to assess and quantify key water quality indicators such as temp...

A rare sighting of two male carrion specialist dung beetles, Scarabaeolus carniphilus Deschodt & Davis, 2015, burying a freshly dead Herald snake (Crotaphopeltis hotamboeia (Laurenti, 1768)) is documented from its discovery in the field and subsequent reburial under laboratory conditions. The species studied is a member of the telecoprid (dung roll...

The moth catcher vine, Araujia sericifera Brotero (Apocynaceae), is a prevalent invader in many countries worldwide, where it has been reported to be a significant threat to biodiversity and agriculture. However, limited knowledge exists surrounding the ecology, invasion and impacts of A. sericifera in South Africa, challenging the implementation o...

Cooperative transport allows for the transportation of items too large for the capacity of a single individual. Beyond humans, it is regularly employed by ants and social spiders where two or more individuals, with more or less coordinated movements, transport food to a known destination. In contrast to this, pairs of male and female dung beetles s...

Water hyacinth is the target of nine biological control agents in South Africa including Neochetina eichhorniae (Warner) and Neochetina bruchi (Hustache) (Coleoptera: Curculionidae). These two weevils have also been released against water hyacinth in Rwanda, but failed to control the weed invasion, possibly due to high turbidity in the country's wa...

Opuntia stricta var. stricta (Haworth.) Haworth (Cactaceae) is an important invasive alien plant (IAP) in South Africa, that invades both disturbed and undisturbed habitats mainly within grasslands and savannas. Fortunately, substantial control has been achieved using the biological control agent, Dactylopius opuntiae (Cockerell) (Hemiptera: Dactyl...

Many insects rely on path integration to define direct routes back to their nests. When shuttling hundreds of meters back and forth between a profitable foraging site and a nest, navigational errors accumulate unavoidably in this compass- and odometer-based system. In familiar terrain, terrestrial landmarks can be used to compensate for these error...

Ball rolling dung beetles use a wide range of cues to steer themselves along a fixed bearing, including the spectral gradient of scattered skylight that spans the sky. Here, we define the spectral sensitivity of the diurnal dung beetle Kheper lamarcki and use the information to explore the orientation performance under a range of spectral light com...

Opuntia engelmannii Salm‐Dyck (Cactaceae:Opuntioideae) is a morphologically variable cactus that has invaded pasture lands in South Africa and Kenya. Biological control of invasive Opuntia species can be very successful when the correct agent is matched with the appropriate host. This research investigated the similarity (morphological and genetic)...

This study investigated the distribution and the tree canopy cover (TCC) of the two most prominent street trees (Jacaranda mimosifolia and Platanus × acerifolia) in Johannesburg, using the multispectral SPOT 6 satellite data and field survey GPS points. The importance of the spectral bands (Blue, Green, Red and NIR) and the NDVI index in discrimina...

The combined impact of biocontrol agents on the seed regenerative capacity, i.e. seed production, seed-rain, soil seedbank, and seedling density, of Lantana camara L. (sensu lato) (Verbenaceae), was measured in the field in an inland area of South Africa. The study was conducted on ten plots (20 x 50 m each) along part of the Sabie River catchment....

South Africa hosts >1.2 million immigrants, 75% from Africa. The inter- and intra-continental diaspora of immigrant groups, and the movement of biological commodities, effects a parallel biological diaspora of plants, animals, and pathogens to regions where they are non-native, and an allied diaspora of traditional practices associated with commodi...

The sun is the most prominent source of directional information in the heading direction network of the diurnal, ball-rolling dung beetle Kheper lamarcki. If this celestial body is occluded from the beetle's field of view, the distribution of the relative weight between the directional cues that remain shifts in favour of the celestial pattern of p...

Urban trees play a critical role in alleviating land surface temperatures in cities. In remote sensing studies, vegetation indices are widely used to examine the relationship between Land Surface Temperature (LST) and vegetation cover. The vegetation cover can be measured using the Normalised Difference Vegetation Index (NDVI). In this study, the L...

Parthenium hysterophorus L. (Asteraceae) is a noxious, annual invasive herb prevalent in more than 50 countries worldwide. In South Africa, the weed is a highly damaging invasive species, particularly in savanna regions, threatening food security, native biodiversity, livelihoods and human health. Given the multitude of threats posed by P. hysterop...

In the last decade, biological control in South Africa has evolved from a classical applied science, allied to an extension service, to a more community engagement-based activity. Therefore, capacity building is important for the sustainability of biological control research and its implementation. In South Africa, a broad approach has been taken t...

Solanum mauritianum Scop. (Solanaceae), colloquially referred to as bugweed in South Africa, remains a widespread invasive tree of global significance. Although biological control (biocontrol) efforts were undertaken from 1984 -2003 in South Africa, the programme eventually only released two agents, the sap-sucking lace bug Gargaphia decoris Drake...

Three weed biological control (biocontrol) programmes are described, all of which are considered to be ‘transfer projects’ that were initiated elsewhere, and on which South Africa has piggybacked its biocontrol efforts. Using knowledge and expertise from international collaborators, South African weed researchers are following a long tradition of t...

The highly invasive Campuloclinium macrocephalum (Asteraceae; ‘pompom weed’), native to South America, was introduced to South Africa where it has flourished and now threatens the native diversity of the grasslands it has invaded. The Argentine C. macrocephalum population is known to comprise at least three ploidy levels, and exhibit aneuploidy. Pl...

Pereskia aculeata Miller (Cactaceae) is a primitive leafy cactus indigenous to Central and South America that has become a problematic invasive alien plant elsewhere in the world. In South Africa the plant invades established forests, clearings, thickets and plantations along the southern and eastern higher rainfall regions of the country. Pereskia...

Path integration is a general mechanism used by many animals to maintain an updated record of their position in relation to a set reference point.1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 To do this, they continually integrate direction and distance information into a memorized home vector. What remains unclear is how this vector is stored, maintained, and...

In nature, nothing is wasted, not even waste. Dung, composed of metabolic trash and leftovers of food, is a high-quality resource and the object of fierce competition. Over 800 dung beetle species (Scarabaeinae) compete in the South African dung habitat and more than 100 species can colonize a single dung pat. To coexist in the same space, using th...

South Africa is home to a native Tamarix species, while two were introduced in the early 1900s to mitigate the effects of mining on soil. The introduced species have spread to other ecosystems resulting in ecological deteriorations. The problem is compounded by hybridization of the species making identification between the native and exotic species...

Tamarix (Tamaricaceae), a phreatophyte genus from the Old World, is a tenacious competitor which has invaded North America (namely the United States and Mexico), Australia, and South Africa amongst other countries. Biological control of invasive Tamarix taxa in South Africa is complicated by the indigenous T. usneoides, which is phylogenetically di...

This dataset is a an inventory of 475 alien plant taxa (447 identified to species), including a photo-guide to 96 plants, mostly sold as traditional medicines in three South African cities by traders of South African, West African, East African, Indian and Chinese origin (Williams et al., 2021). The dataset also incorporates species documented in a...

Insect declines have been attributed to several drivers such as habitat loss, climate change, invasive alien species and insecticides. However, in the global context, these effects remain patchy, whereas insect losses appear to be consistent worldwide. Increases in atmospheric CO2 concentrations are known to have indirect effects on herbivorous ins...

Increasing global light pollution¹,² threatens the night-time darkness to which most animals are adapted. Light pollution can have detrimental effects on behavior,3, 4, 5 including by disrupting the journeys of migratory birds,⁵,⁶ sand hoppers,7, 8, 9 and moths.¹⁰ This is particularly concerning, since many night-active species rely on compass info...

South Africa’s colonial past has shaped its environmental history, including introductions of alien plants. Indentured Indian labourers, mainly from Tamil Nadu, that were brought to South Africa in the 1860s, acquired knowledge of Zulu healing practices and plants. This translocation of traditional medical knowledge (mostly Ayurvedic), and the adop...

Simple Summary To escape competition for food at the dung pat, ball-rolling dung beetles shape a piece of dung into a sphere and roll it away. To maintain their bearing, these beetles integrate directional information from a range of celestial cues. For the majority of diurnal dung beetles living in open habitats, the most dominant of these cues is...

Dactylopius opuntiae ‘stricta’ lineage was released more than 20 years ago in South Africa where it has successfully controlled Opuntia stricta. However, its host preference had not been tested against all invasive cacti in South Africa. Therefore, the possibility exists that it might successfully control other invasive cacti. We compared the perfo...

Urban animal ecology is a rapidly growing research area, yielding fascinating insights into the patterns and processes that shape biodiversity in the city. However, much of this research has focused on cities in the developed world, where the mechanisms affecting biodiversity might be very different to those in the developing cities of the Global S...

Distant and predictable features in the environment make ideal compass cues to allow movement along a straight path. Ball-rolling dung beetles use a wide range of different signals in the day or night sky to steer themselves along a fixed bearing. These include the sun, the Milky Way, and the polarization pattern generated by the moon. Almost two d...

Reducing the reproductive output of an invasive weed using biocontrol can result in a decrease in population density and help control the spread of the weed. Two biocontrol agents, a stem gall fly, Procecidochares utilis (Tephritidae), and a leaf-spot fungal pathogen, Passalora ageratinae (Mycosphaerellaceae), have been released against Crofton wee...

Diverse freshwater biological communities are threatened by invasive aquatic alien plant (IAAP) invasions and consequently, cost countries millions to manage. The effective management of these IAAP invasions necessitates their frequent and reliable monitoring across a broad extent and over a long-term. Here, we introduce and apply a monitoring appr...

Unusual amongst dung beetles, Scarabaeus galenus digs a burrow that it provisions by making repeated trips to a nearby dung pile. Even more remarkable is that these beetles return home moving backwards, with a pellet of dung between their hind legs. Here, we explore the strategy that S. galenus uses to find its way home. We find that, like many oth...

The annual herb Parthenium hysterophorus L. (Asteraceae), remains one of Southern Africa's most significant invasive weeds, commonly invading savannas, and their rangelands, causing severe losses to agriculture, livestock production and native biodiversity. Previous studies have suggested that perennial grasses may act as useful competitive species...

Mapping of vegetation at the species level using hyperspectral satellite data can be effective and accurate because of its high spectral and spatial resolutions that can detect detailed information of a target object. Its wide application, however, not only is restricted by its high cost and large data storage requirements, but its processing is al...

Tamarix species are major terrestrial riparian invaders in South Africa. The biocontrol agent, Diorhabda carinulata (Coleoptera: Chrysomelidae), was tested as the initial candidate agent in South Africa due to its success against invasive Tamarix in North America. The ability of Tamarix to grow across a broad soil salinity gradient may affect its s...

The life cycle of almost all dung beetles revolve around mammalian dung, the feed on dung, look for mating partners on dung and lay eggs in the dung. We know they feed on dung, but we still do not understand how exactly they filter‐feed on the dung and which particles size range they are ingesting. The aim on this study was to investigate the filte...

Invasive alien plants are considered as a major threat to many ecological and socioeconomic systems. Nevertheless, the management of some of these plants is often controversial due to the positive socioeconomic and ecosystem roles they play. This necessitates proper mapping and monitoring of the extent and spatial distribution of such plants to pri...

Heavy metal polluted soils can be remediated using plants, a process called phytoremediation. However, high concentrations of heavy metals can negatively affect plant physiology and growth. We experimentally evaluated the effects of cadmium (Cd) on the growth, (i.e. height, shoot and biomass) and physiology (i.e. leaf chlorophyll and relative water...

There is evident variation in body size amongst Anthonomus santacruzi Hustache, 1924, weevils. The aims of this study were to assess if the variation in body size in A. santacruzi weevils is a result of sexual dimorphism and what features can be used to distinguish males from females. The weevils were collected from field sites in Mpumalanga, South...

This Commentary is a response to a Commentary published in the May/June 2020 issue: Nattrass N. Why are black South African students less likely to consider studying biological sciences? S Afr J Sci. 2020;116(5/6), Art. #7864, 2 pages. https://doi.org/10.17159/sajs.2020/7864 Responses to the Commentary in the May/June 2020 issue have been publish...

The spatial and temporal knowledge on spread of invasive aquatic plants helps to determine their extent, abundance, and propagation rates in invaded water systems. Water hyacinth Eichhornia crassipes (Liliales: Pontederiaceae) appeared in Rwandan water bodies in 1957, and it was legislated and accepted as a problematic invasive species in Rwanda in...

To transport their balls of dung along a constant bearing, diurnal savannah-living dung beetles rely primarily on the sun for compass information. However, in more cluttered environments, such as woodlands, this solitary compass cue is frequently hidden from view by surrounding vegetation. In these types of habitats, insects can, instead, rely on s...

Invasive alien plant species negatively affect agricultural production, degrade conservation areas, reduce water supplies, and increase the intensity of wild fires. Since 1913, biological control agents i.e. plant-feeding insects, mites, and fungal pathogens, have been deployed in South Africa to supplement other management practices (herbicides an...

Our changing relationship with the biosphere is one of many anxieties that human society currently confronts. The paradox that some biodiversity that has been moved across the planet by human trade could actually be harmful is unknown to many people. They are either oblivious, or perceive nature as being under threat, rather than as threatening in...

Alien taxa have been introduced to South Africa through a wide variety of pathways, and have subsequently been intentionally or accidentally dispersed across the country. While many introductions to South Africa have been intentional, alien taxa have also been accidentally introduced, or have spread unaided into the country from neighbouring countr...

It is generally suggested that invasive alien plant species (IAPS) negatively affect livelihoods. However, there is a need to find more generalisable patterns of IAPS impacts on livelihoods, which are useful for decision making at broad scales. Here we test the hypothesis that across South Africa poorer communities with high reliance on provisionin...

BACKGROUND The noxious annual herb, Parthenium hysterophorus L. (Asteraceae), is an invasive weed of global significance, threatening food security, biodiversity and human health. In South Africa, chemical control is frequently used to manage P. hysterophorus, however, concern surrounds increasing atmospheric CO2 levels, which may reduce the effica...

In the original publication of the article, the family name of the corresponding author was missed out. The correct author name is Nic Venter.

Lantana camara L. (Verbenaceae) is a weed of significant concern in many tropical and subtropical countries. This work aimed to quantify the combined impact of the established suite of lantana biocontrol agents on plant growth under field conditions in an inland area with a continental climate in South Africa. An insecticidal exclusion method was e...

Street trees in urban planning have a long history as providers of an amicable environment for urban dwellers. Nevertheless, street trees are not always without a challenge, their ecosystem disservices include, inter alia, cracking pavements and foundations due to wandering tree roots that destroy concrete or asphalt surfaces. Thus, effective mappi...

The sap-sucking lace bug, Teleonemia scrupulosa (Hemiptera: Tingidae), was released as a biocontrol agent against the invasive shrub Lantana camara (Verbenaceae) in South Africa in 1961. Like many agents released against the weed in South Africa, success has been varied, largely attributed to the sheer number of L. camara varieties involved and the...

Water hyacinth, Eichhornia crassipes (C. Mart) Solms (Pontederiaceae), is an invasive aquatic macrophyte with major negative economic and ecological impacts in Rwanda and other East African countries since its establishment in the region in the 1960s. Reliable estimates of water hyacinth distribution are required to determine the severity of the pr...

Parthenium hysterophorus L. is a noxious annual invasive herb which threatens biodiversity, food security and human and animal health in various tropical and sub-tropical regions globally. Given that these regions, including South Africa, experience frequent drought events, it is important that the invasive potential of this weed be better understo...

Salt cedar, Tamarix, is a genus of many Eurasian shrubby tree species in the family Tamaricaceae that is represented by one native (Tamarix usneoides E.Mey.) and two exotic (Tamarix ramosissima Ledeb. and T. chinensis Lour.) species in South Africa. The exotic Tamarix spp. have become invasive in South Africa and are targeted for biological control...

Moving along a straight path is a surprisingly difficult task. This is because, with each ensuing step, noise is generated in the motor and sensory systems, causing the animal to deviate from its intended route. When relying solely on internal sensory information to correct for this noise, the directional error generated with each stride accumulate...

In South Africa, the leaf-feeding beetle, Zygogramma bicolorata Pallister (Coleoptera: Chyrsomelidae), was released in 2013 against the invasive annual herb Parthenium hysterophorus L. (Asteraceae: Heliantheae). Poor field establishment and variable incidence of the beetle, during the first few years after release, have led to concerns surrounding...

This study, investigated the salt excretion efficiency and the level of the physiological response to salt-induced stresses between the native and exotic Tamarix species as well as their hybrids (Tamarix chinensis × Tamarix ramosissima and Tamarix chinensis × Tamarix usneoides). Ten potted plants from each of the five taxa were exposed to salt at a...

Two biocontrol agents, a leaf-spot pathogen, Passalora ageratinae, and a stem gall fly, Procecidochares utilis, have been released against Crofton weed, Ageratina adenophora (syn. Eupatorium adenophorum) (Asteraceae), in South Africa. This work reports the first post-release evaluation of the effect of both agents acting together in the field. A gr...

Significance We show that South African dung beetles use a multimodal orientation compass based on celestial cues and wind cues to steer across the savanna. The cue preference between these 2 modalities is set in a flexible manner: at low sun elevations, the beetles use a celestially driven compass, but switch to a wind-dominated compass at high su...

Several countries globally, including South Africa, have been invaded by at least one of five species of Tamarix. South Africa therefore considered using one or more species of leaf-feeding beetles in the genus Diorhabda (Coleoptera: Chrysomelidae), including Diorhabda carinulata, against invasive T. ramosissima and T. chinensis, since the beetles...

An important resource partitioning strategy allowing dung beetles to coexist in the same habitat, while utilising the same food, is species’ separation of activity times. After establishing the diel activity period of three closely related, co-occurring dung beetles, we examined their eye and wing morphology. Absolute and relative eye size, and fac...

This laboratory-based study sought to determine the efficacy of using carbofuran in an exclusion experiment aimed at assessing the impacts of biocontrol agents on Lantana camara L. (sensu lato) (Verbenaceae). Two separate experiments were conducted, the first one on insect-free plants, to determine the effects of carbofuran solely on plant growth;...

The exotic Tamarix chinensis and T. ramosissima, believed to have been introduced into South Africa in the early 1900s to control erosion on mine dumps, are invading riparian zones and have been proven to hybridise with T. usneoides, which is native to southern Africa. In this study, we document the abundance of invasive Tamarix genotypes in South...

For many insects, celestial compass cues play an important role in keeping track of their directional headings. One well-investigated group of celestial orientating insects are the African ball-rolling dung beetles. After finding a dung pile, these insects detach a piece, form it into a ball and roll it away along a straight path while facing backw...

For polarized light to inform behaviour, the typical range of degrees of polarization observable in the animal's natural environment must be above the threshold for detection and interpretation. Here, we present the first investigation of the degree of linear polarization threshold for orientation behaviour in a nocturnal species, with specific ref...

Edited by JS Boatwright Genetic diversity information can be valuable for establishing successful management strategies for indigenous and invasive species. Here we conducted a genetic assessment of two invasive and one native Tamarix species in South Africa, where all species are known to hybridize. Hybridization can encourage biological invasion...

The poster describes the following: 1) Host specificity of Diorhabda carinulata, 2) the use of hyperspectral remote sensing to determine the extent of the Tamarix invasion in South Africa and 3) the effect of inundation (flooding) on Tamarix physiology (e.g. photosynthesis, stomatal conductance)

A review of the research being done on Tamarix in South Africa. The poster describes the following: 1) host specificity of the Tamarix beetle, Diorhabda carinulata, 2) the use of hyper-spectral remote sensing as a tool to show the extent of the Tamarix invasion in South Africa, and 3) the effect of inundation (flooding) on the physiology (photosynt...

For polarized light to inform behaviour, the typical range of degrees of polarization observable in the animal’s natural environment must be above the threshold for detection and interpretation. Here we present the first investigation of the degree of linear polarization threshold for orientation behaviour in a nocturnal species, with specific refe...

Water hyacinth is one of the five worst aquatic weeds that invades many SouthAfrican water bodies. It has been the target of at least eight biological control agents, including the water hyacinth weevil, Neochetina eichhorniae (Warner) (Coleoptera: Curculionidae). However, their success has been constrained by the high levels of eutrophication in S...

Temperature is one of the main factors that determine sexual reproduction in terrestrial and emergent aquatic plant species. The effect of temperature on sexual reproduction and seed production of Glyceria maxima (Hartm.) Holmb. in the southern hemisphere is unknown. Glyceria maxima collections in February 2010 at three isolated infestations in Kwa...

The invasive tree Solanum mauritianum Scopoli remains one of the world’s most widespread environmental weeds. Despite biocontrol providing one of the few viable long-term solutions to tackling S. mauritianum invasions globally, only South Africa and, more recently, New Zealand, have programmes in place. Ongoing biocontrol efforts against S. mauriti...

Most species of Tamarix originate in Eurasia and at least five species have become invasive around the world, including South Africa. However, T. usneoides is indigenous to southern Africa, where the potential for biological control of the invasive species is being investigated. Recent research on the invasive species is reviewed here with particul...

The annual shrub, Parthenium hysterophorus L. (Asteraceae), is a severe noxious weed of global significance, having been the target of control programmes in several affected countries. Biological control efforts in South Africa have seen a total of four agents released to date, one of the most promising of which is the leaf-feeding beetle, Zygogram...

Water hyacinth (Eichhornia crassipes Mart. Solms Pontederiaceae) mainly occurs as a free-floating aquatic plant, but can survive decreasing water levels when rooted in soil. This adaptation to seasonal fluctuations in hydrology may contribute to its invasive potential in natural and man-made water bodies, where stranded plants can take root. To und...

Nocturnal dung beetles ( Scarabaeus satyrus ) are currently the only animals that have been demonstrated to use the Milky Way for reliable orientation. In this study, we tested the capacity of S. satyrus to orient under a range of artificial celestial cues, and compared the properties of these cues with images of the Milky Way simulated for a beetl...

Invasive alien species are routinely moved around the world as horticultural specimens. An additional route through the traditional medicine trade may exist, especially where cultures from different continents coalesce. South African traditional medicine, for example, has a long history of association with its Indian Ayurvedic equivalent via migrat...

Hybridization is regarded as a rapid mechanism for increasing genetic variation that can potentially enhance invasiveness. Tamarix hybrids appear to be the dominant genotypes in their invasions. Exotic Tamarix are declared invasive in South Africa and the exotic T. chinensis and T. ramosissima are known to hybridize between themselves, and with the...

Vertebrate dung is central to the dung beetle life cycle, constituting food for adults and a protective and nutritive refuge for their offspring. Adult dung beetles have soft mandibles and feed primarily on nutritionally rich dung particles, while larvae have sclerotized mandibles and consume coarser dung particles with a higher C/N ratio. Here, us...

The aim of this study was to investigate the overall root/shoot allocation of metal contaminants, the amount of metal removal by absorption and adsorption within or on the external root surfaces, the dose-response of water hyacinth metal uptake, and phytotoxicity. This was examined in a single-metal tub trial, using arsenic (As), gold (Au), copper...

In order to protect their food from competitors, ball-rolling dung beetles detach a piece of dung from a pile, shape it into a ball, and roll it away along a straight path [1]. They appear to rely exclusively on celestial compass cues to maintain their bearing [2–8], but the mechanism that enables them to use these cues for orientation remains unkn...