John S. Terblanche

John S. Terblanche
Stellenbosch University | SUN · Department of Conservation Ecology and Entomology

PhD

About

241
Publications
58,601
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
9,242
Citations
Citations since 2016
100 Research Items
5949 Citations
201620172018201920202021202202004006008001,000
201620172018201920202021202202004006008001,000
201620172018201920202021202202004006008001,000
201620172018201920202021202202004006008001,000
Introduction
My interests lie in terrestrial animals and their environmental adaptations. My research group works on a range of topics, mainly using insects as model systems, from mechanistic, cellular physiology to large-scale ecological and evolutionary studies. We currently focus on a set of related research questions in climate change biology, functional ecology, invasion biology, pest management and physiological ecology.
Additional affiliations
January 2008 - July 2016
Stellenbosch University
Position
  • Professor (Full)

Publications

Publications (241)
Article
Oxygen- and capacity-limited thermal tolerance (OCLTT) is a controversial hypothesis claiming to explain variation in, and mechanistically determine, animal thermal limits. The lack of support from Insecta is typically argued to be a consequence of their high performance respiratory systems. However, no studies have reported internal body oxygen le...
Article
Terrestrial insects are responding to ongoing climate change. While these responses have been primarily linked to rising temperatures, insects are sensitive to desiccation, and the impacts of altered precipitation regimes remain relatively unexplored. Here, we develop a mechanistic model of survival and performance responses to both temperature and...
Article
Insects exchange respiratory gases using an astonishing diversity of patterns. Of these, discontinuous gas exchange cycles (DGCs) have received the most study, but there are many other patterns exhibited intraspecifically and interspecifically. Moreover, some individual insects transition between patterns based on poorly understood combinations of...
Article
Dispersal is a central requirement of a successful sterile insect release programme, but field-released false codling moth (FCM) typically suffer from poor dispersal ability, especially at low ambient temperatures. Here we test the hypothesis that poor activity and dispersal in FCM is caused by delayed or perturbed recovery of ion and/or water home...
Article
Plastic responses figure prominently in discussions on insect adaptation to climate change. Here we review the different types of plastic responses and whether they contribute much to adaptation. Under climate change, plastic responses involving diapause are often critical for population persistence, but key diapause responses under dry and hot con...
Article
Full-text available
Climate warming is considered to be among the most serious of anthropogenic stresses to the environment, because it not only has direct effects on biodiversity, but it also exacerbates the harmful effects of other human-mediated threats. The associated consequences are potentially severe, particularly in terms of threats to species preservation, as...
Article
Full-text available
Insects have the ability to readily adapt to changes in environmental conditions, however the strength of local environmental adaptation signals under divergent conditions and the occurrence of trait inertia after relaxation of selection, remains poorly understood, especially for traits of climate stress resistance (CSR) and their phenotypic plasti...
Article
Full-text available
Extreme temperature events are increasing in frequency and intensity due to climate change. Such events threaten insects, including pollinators, pests and disease vectors. Insect critical thermal limits can be enhanced through acclimation, yet evidence that plasticity aids survival at extreme temperatures is limited. Here, using meta-analyses acros...
Article
Full-text available
Biotic interactions can modulate the responses of organisms to environmental stresses, including diet changes. Gut microbes have substantial effects on diverse ecological and evolutionary traits of their hosts, and microbial communities can be highly dynamic within and between individuals in space and time. Modulations of the gut microbiome composi...
Article
Females and males have divergent strategies of energy investment, so the thermal preference of each sex in insects may differ because energetic conversion of metabolic reserves is dependent on temperature. We determined the thermal preference of virgin, sexually mature Mediterranean fruit flies, Ceratitis capitata, and found that males preferred a...
Article
Full-text available
The ambrosia beetle Euwallacea fornicatus (Polyphagous Shot Hole Borer; PSHB), native to Asia, was documented in South Africa for the first time in 2012. Death of susceptible host trees is caused by blocking of xylem tissues by the mutualistic plant-pathogenic fungus, Fusarium euwallaceae and extensive tunnelling by the beetles into the sapwood. Wi...
Article
Cold acclimation may enhance low temperature flight ability, and salt loading can alter an insects’ cold tolerance by affecting their ability to maintain ion balance in the cold. Presently however, it remains unclear if dietary salt impacts thermal acclimation of flight ability in insects. Here, we examined the effect of a combination of dietary sa...
Article
Full-text available
The relative costs and benefits of thermal acclimation for manipulating field performance of pest insects depend upon a number of factors including which traits are affected and how per- sistent any trait changes are in different environments. By assessing plastic trait responses of Ceratitis capitata (Mediterranean fruit fly) across three distinct...
Article
Full-text available
Insects are mass-reared for release for biocontrol including the sterile insect technique. Insects are usually reared at temperatures that maximize the number of animals produced, are chilled for handling and transport, and released into the field, where temperatures may be considerably different to those experienced previously. Insect thermal biol...
Article
Full-text available
Here we aimed to assess whether variation in (1) developmental temperature and (2) transport conditions influenced the low-temperature performance and flight ability of false codling moth (FCM) adults in an SIT programme. To achieve the first aim, larvae were exposed to either a (control) (constant 25 °C), a cold treatment (constant 15 °C) or a flu...
Article
Full-text available
Various combinations and concentrations of cholesterol (C) and stigmasterol (S) were added into a base diet developed for Eldana saccharina. Survival of inoculated neonate was high on all diets (>92% at day 20 and >95% at day 27). Fastest larval development occurred on the minimum specification (MS) (+1.0 gS) and MS (+0.2 gC: 0.2 gS) diets (72 and...
Article
Agricultural biosecurity interventions are aimed at minimising introductions of harmful non‐native organisms to new areas via agricultural trade. To prioritise such interventions, historical data on interceptions have been used to elucidate which factors determine the likelihood that a particular import is carrying a harmful organism. Here we use a...
Preprint
Full-text available
Autophagy is a physiological process that facilitates the recycling of intracellular cytosolic components as a response to diverse stressful conditions. By increasing the turnover of damaged structures and clearance of long-lived and larger protein aggregates, the induction of autophagy increases tolerance to abiotic stress in a range of organisms....
Article
Full-text available
Understanding of the morphological and physiological correlates of competitive behaviours can provide important insights into the ecology of competition, home range size and resource consumption. Here, we first estimated and defined sexual dimorphism in a poorly studied African cerambycid species, Cacosceles newmannii. We then assessed morphologica...
Article
To forecast climate change impacts across habitats or taxa, thermal vulnerability indices (e.g., safety margins and warming tolerances) are growing in popularity. Here, we present their history, context, formulation, and current applications. We highlight discrepancies in terminology and usage, and we draw attention to key assumptions underpinning...
Article
Full-text available
Developmental and adult thermal acclimation can have distinct, even opposite, effects on adult heat resistance in ectotherms. Yet, their relative contribution to heat-hardiness of ectotherms remains unclear despite the broad ecological implications thereof. Furthermore, the deterministic relationship between heat-knockdown and recovery from heat st...
Article
Historic approaches to understanding biological responses to climate change have viewed climate as something external that happens to organisms. Organisms, however, at least partially influence their own climate experience by moving within local mosaics of microclimates. Such behaviors are increasingly being incorporated into models of species dist...
Article
Full-text available
DNA barcoding has been succesfully used for bio-surveillance of forest and agricultural pests in temperate areas, but has few applications in the tropics and particulary in Africa. Cacosceles newmannii (Coleoptera: Cerambycidae) is a Prioninae species that is locally causing extensive damage in commercially-grown sugarcane in the KwaZulu-Natal Prov...
Article
Full-text available
Quantifying insect respiratory structures and their variation has remained challenging due to their microscopic size. Here we measure insect tracheal volume using X-ray micro-tomography (μCT) scanning (at 15 μm resolution) on living, sedated larvae of the cerambycid beetle Cacosceles newmannii across a range of body sizes. In this paper we provide...
Preprint
Full-text available
Quantifying insect respiratory structures and their variation has remained challenging due to their microscopic size. Here we measure insect tracheal volume using X-ray micro-tomography (µCT) scanning (at 15 µm resolution) on living, sedated larvae of the cerambycid beetle Cacosceles newmannii across a range of body sizes. In this paper we provide...
Article
Full-text available
Trait–environment interactions have contributed to the remarkable plant radiations in the Cape Floristic Region (CFR) of southern Africa. Whether such interactions have also resulted in the diversification of the invertebrate fauna, independently of direct associations with plants is, however, not clear. One candidate where this may be the case is...
Article
Understanding sources of variation in animal thermal limits is critical to forecasting ecological responses to climate change. Here, we estimated upper and lower thermal limits, and their capacity to respond to thermal acclimation, in several species and populations of diving beetles (Dytiscidae) from diverse geographic regions representative of va...
Article
An outbreak of Cacosceles newmannii (Coleoptera: Cerambycidae) was detected for the first time on sugarcane (Saccharum spp.) in 2015 in KwaZulu‐Natal, South Africa. Although primary host plants of this native species remain unknown, these are central to testing hypotheses concerning the outbreak. We hypothesized that this species has undergone a ho...
Article
Full-text available
Biosecurity interception records are crucial data underlying efforts to predict and manage pest and pathogen introductions. Here we present a dataset containing information on imported plant products inspected by the South African Department of Agriculture's laboratories between 1994 and 2019 and the contaminant organisms found on them. Samples wer...
Article
Full-text available
How respiratory structures vary with, or are constrained by, an animal’s environment is of central importance to diverse evolutionary and comparative physiology hypotheses. To date, quantifying insect respiratory structures and their variation has remained challenging due to their microscopic size, hence only a handful of species have been examined...
Article
Full-text available
The establishment success of a population is a function of abiotic and biotic factors and introduction dynamics. Understanding how these factors interact has direct consequences for understanding and managing biological invasions and for applied ecology more generally. Here we use a mesocosm approach to explore how the size of founding populations...
Article
Metabolic rate, and the flexibility thereof, is a complex trait involving several inter-linked variables that can influence animal energetics, behavior, and ultimately, fitness. Metabolic traits respond readily to ambient temperature variation, in some cases increasing relative or absolute energetic costs, while in other cases, depending on the org...
Article
Full-text available
The fitness consequences of thermal plasticity of functional traits of insects, and the life stages at which these responses manifest, remain a subject of much debate. Here, we examine whether a short-term exposure to cold, medium or warm fluctuating temperature regimes during development (larval or adult) affects adult performance, thermal toleran...
Article
Full-text available
Quantifying intraspecific variation in heat tolerance is critical to understand how species respond to climate change. In a previous study, we recorded variability in critical thermal maxima (CTmax) by 3 °C among populations of small Iberian lizard species, which could substantially influence predictions of climate-driven activity restriction. Here...
Article
1. Neochetina eichhorniae is the most widely established biocontrol agent on water hyacinth populations around South Africa. However, some N. eichhorniae populations have failed to adequately control their host population, specifically those exposed to cold conditions. 2. The aim of this study was to determine whether two climatically distinct popu...
Article
Specific trait‐environment interactions have led to globally unusual botanical radiations in the Cape Floristic Region (CFR) of South Africa. Yet it is unclear whether such interactions have similarly resulted in the diversification of the fauna independently of associations with plants. We explore this question for the Collembola genus Seira, whic...
Article
Acclimation and other forms of plasticity that can increase stress resistance feature strongly in discussions surrounding climate change impacts or vulnerability projections of insects and other ectotherms. There is interest in compiling databases for assessing the adequacy of acclimation for dealing with climate change. Here we argue that the natu...
Chapter
Full-text available
South Africa has a rich history of managing invasive alien animal populations. This chapter explores examples of animal control projects, their resourcing and degree of success or failure. Out of 1023 alien animal species present in South Africa, 80 are designated for compulsory control or eradication in national legislation, and 24 are currently b...
Article
Full-text available
Although it is well known that insects are sensitive to temperature, how they will be affected by ongoing global warming remains uncertain because these responses are multifaceted and ecologically complex. We reviewed the effects of climate warming on 31 globally important phytophagous (plant‐eating) insect pests to determine whether general trends...
Article
Full-text available
Temperature has a profound impact on insect fitness and performance via metabolic, enzymatic or chemical reaction rate effects. However, oxygen availability can interact with these thermal responses in complex and often poorly understood ways, especially in hypoxia-adapted species such as those living underground, at high elevation or within plant...
Article
What makes some species successful invaders while others fail, and why some invaders have major impacts in invaded ecosystems are pivotal questions that are attracting major research effort. The increasing availability of high resolution, georeferenced stable isotope landscapes (‘isoscapes'), coupled with the commercialization of stable isotope‐enr...
Article
Bactrocera dorsalis (Hendel) and Ceratitis capitata (Wiedemann) are highly polyphagous fruit fly species and important pests of commercial fruit in regions of the world where they are present. In South Africa, B. dorsalis is now established in the north and northeastern parts of the country. B. dorsalis is currently absent in other parts of the cou...
Poster
Full-text available
Larvae of a long horn beetle were found for the first time feeding on sugarcane in the Entumeni district of KwaZulu-Natal in 2015. This beetle was later identified as Cacosceles newmannii (Thomson) (Coleoptera: Cerambycidae: Prioninae: Cacoscelini). The larvae of this beetle cause significant damage to sugarcane, resulting in important economic los...
Poster
Full-text available
The recent shift of the indigenous longhorn beetle Cacosceles newmannii (Coleoptera: Cerambycidae) into sugarcane of KwaZulu-Natal has resulted in widespread concern surrounding its pest status and further potential for spread and damage in sugarcane crops. Although historically widespread in many biomes in southern Africa, C. newmannii is though...
Article
Thermal flight performance curves (TFPCs) may be a useful proxy for determining dispersal on daily timescales in winged insect species. Few studies have assessed TFPCs across a range of species under standard conditions despite that they may be useful in predicting variation in performance, abundance or geographic range shifts with forecast climate...
Article
Full-text available
Background: Data on the current species diversity from the Drosophilidae family in South Africa is limited or outdated.Objectives: Using haphazard, limited trapping for a different study, we serendipitously report on and document Drosophilidae species in two distinct regions (representing a sub-tropical and a Mediterranean climate region) of South...
Article
Full-text available
Cacosceles newmannii (Coleoptera: Cerambycidae) is an emerging pest of sugarcane in South Africa. The larvae of this cerambycid beetle live within the sugarcane stalk and drill galleries that considerably reduce sugar production. To provide an alternative to chemical control, entomopathogenic nematodes and fungus were investigated as potential biol...
Article
Processing food (e.g. ingestion, digestion, assimilation) requires energy referred to as specific dynamic action (SDA) and is at least partially fuelled by oxidation of the nutrients (e.g. proteins and lipids) within the recently ingested meal. In ectotherms, environmental temperature can affect the magnitude and/or duration of the SDA, but is like...
Article
• In sterile insect technique programmes, temperatures experienced by insects during rearing and handling, along with cool temperatures after release, can negatively affect performance and activity levels. Phenotypic plasticity (trait modifications caused by prior stress exposure) can offset these effects but is poorly understood in many species an...
Conference Paper
Full-text available
The recent host shift of the indigenous longhorn beetle Cacosceles newmannii (Coleoptera: Cerambycidae) from indigenous vegetation onto sugarcane in the KwaZulu-Natal Province of South Africa has resulted in widespread concern surrounding its pest status due to severe crop damage and significant economic losses for growers. This dramatic host shift...
Preprint
Full-text available
Phytophagous insect pests strongly affect the productivity and profitability of agriculture and forestry. Despite the well-known sensitivity of insects to abiotic effects such as temperature, their potential responses to ongoing climate change remain unclear. Here we compile and review documented climate change responses of 31 of the globally most...
Conference Paper
Full-text available
The recent invasion of the indigenous longhorn beetle Cacosceles newmannii (Coleoptera: Cerambycidae) into sugarcane of KwaZulu-Natal has resulted in widespread concern surrounding its pest status and further potential for spread and damage in surrounding sugarcane crops. Its dramatic host shift from indigenous vegetation can be attributed to sever...
Conference Paper
Full-text available
The recent shift of the indigenous longhorn beetle Cacosceles newmannii (Coleoptera: Cerambycidae) into sugarcane of Kwa-Zulu Natal has resulted in widespread concern surrounding its pest status and further potential for spread and damage in sugarcane crops. Although historically widespread in many biomes in southern Africa, C. newmannii is though...
Article
Full-text available
Traits of thermal sensitivity or performance are typically the focus of species distribution modelling. Among-population trait variation, trait plasticity, population connectedness and the possible climatic covariation thereof are seldom accounted for. Here, we examine multiple climate stress resistance traits, and the plasticity thereof, for a glo...