Christian W W Pirk

Christian W W Pirk
University of Pretoria | UP · Department of Zoology and Entomology

PhD Entomology

About

239
Publications
107,248
Reads
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5,672
Citations
Introduction
Contact the SIRG @ UP if you are interested in doing a PostDoc in South Africa on social insects
Additional affiliations
January 2007 - present
July 2005 - present
Zhejiang University
Position
  • Collaboration with Zhejiang University
May 2005 - present
King Mongkut's University of Technology Thonburi
Position
  • Collaboration with King Mongkut's University of Technology Thonburi
Education
January 2000 - April 2002
Rhodes University
Field of study
  • Entomology
October 1994 - July 1999
Technische Universität Berlin
Field of study
  • Biologie & Mathematik

Publications

Publications (239)
Article
Full-text available
Honey bees process nectar into honey by active evaporation on the tongue and passive evaporation involving nest ventilation and fanning behaviour, as well as enzymatic action. The elimination of excess water from nectar carries considerable energetic costs. The concentration of the nectar load is assumed to remain constant during transport. However...
Article
Full-text available
Progress is required in response to how cities can support greater biodiversity. This calls for more research on how landscape designers can actively shape urban ecologies to deliver contextspecific empirical bases for green space intervention decisions. Design experiments offer opportunities for implemented projects within real-world settings to s...
Chapter
About the book: This is the first collection of writing by various UP academics about reimagining UP and how it may look in the future. These are opinion pieces, thoughts and reflections about the University and other collections will be published as contributions are received.
Article
We evaluated craniometric sexual dimorphism and ontogenetic (age) variation in invasive Rattus norvegicus and R. rattus from urban and peri-urban areas of Gauteng Province, South Africa, using univariate and multivariate analyses. Two-way analysis of variance (ANOVA), percent contribution of the sum of squares (%SSQs) of each source of variation, p...
Article
Introduction Host shifts of parasites can have devastating effects on novel hosts. One remarkable example is that of the ectoparasitic mite Varroa destructor, which has shifted hosts from Eastern honey bees (Apis cerana) to Western honey bees (Apis mellifera) and posed a major global threat to apiculture and wild honey bees. Objectives and methods...
Article
Full-text available
Kairomones are semiochemicals that are emitted by an organism and which mediate interspecific interaction that is of benefit to an organism of another species that receives these chemical substances. Parasitoids find and recognize their hosts through eavesdropping on the kairomones emitted from the by-products or the body of the host. Hemipteran in...
Article
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The contribution of seasonality in species communities to elevational diversity of tropical insects remains poorly understood. We here assessed seasonal patterns and drivers of bee diversity in the Eastern Afromontane Biodiversity Hotspot, Kenya, to understand the contribution of seasonality to elevational biodiversity patterns. Bee species and pla...
Article
Full-text available
Many parts of the globe experience severe losses and fragmentation of habitats, affecting the self-sustainability of pollinator populations. A number of bee species coexist as wild and managed populations. Using honey bees as an example, we argue that several management practices in beekeeping threaten genetic diversity in both wild and managed pop...
Article
Full-text available
Semiochemicals such as herbivore-induced plant volatiles (HIPVs) and host chemicals serve as communication signals for parasitoids searching for oviposition sites. The braconid koinobiont endoparasitoid Dolichogenidea gelechiidivoris (Hymenoptera: Braconidae) efficiently parasitises larvae of Tuta absoluta (Lepidoptera: Gelechiidae), a major pest o...
Article
Three species of Rattus, Norway rat (R. norvergicus), black rat (R. rattus) and Asian house rat (R. tanezumi) are currently known to occur in South Africa. The latter two species are cryptic and form part of the Rattus rattus species complex. Historically, R. norvegicus has been reported to occur along the coast and in urban centres, R. rattus is w...
Article
Full-text available
Hypopharyngeal gland (HPG) development in honey bee workers is primarily age-dependent and changes according to the tasks performed in the colony. HPG activity also depends on colony requirements and is flexible in relation to the need for feeding brood. Very little is known about HPG development in the honey bee subspecies found in Southern Africa...
Article
Full-text available
Bee lice (Braulidae) are small parasitic flies, which are adapted to live on their bee host. As such, the wingless Braula coeca is a parasite of the common honey bee Apis mellifera and it is well adapted to attach to its hairy surface. The attachment system of B. coeca provides a secure grip on the fine setae of the bee. This is crucial for the par...
Article
Monitoring the effectiveness of tsetse fly control interventions that aim to reduce transmission of African trypanosomiasis requires highly efficient sampling tools that can catch flies at low densities. The sticky small target (StS-target) has previously been shown to be more effective in sampling Glossina fuscipes fuscipes compared to the biconic...
Article
Full-text available
Background: Black screen fly round (BFR) is a mobile sampling method for Glossina morsitans. This technique relies on the ability of operator(s) to capture flies landing on the screen with hand nets. In this study, we aimed to evaluate a vehicle-mounted sticky panel trap (VST) that is independent of the operator's ability to capture flies against...
Article
Full-text available
Background Biological control plays a key role in reducing crop damage by Tuta absoluta (Meyrick) and Trialeurodes vaporariorum (Westwood) which cause huge yield losses in tomato (Solanum lycopersicum L.). The mirid predator Nesidiocoris tenuis (Reuter) preys heavily on these pests, with satisfying control levels in tomato greenhouses. Although N....
Article
Full-text available
Variation in vector traits can modulate local scale differences in pathogen transmission. Here, we compared seasonal variation in the wing length (proxy for body size) and energy reserves of adult wild-caught Aedes aegypti populations from a dengue endemic (Kilifi) and non-endemic (Isiolo) area of Kenya. Vector sampling in the dengue endemic site w...
Article
Full-text available
Kairomones are chemical signals that mediate interspecific interactions beneficial to organisms that detect the cues. These attractants can be individual compounds or mixtures of herbivore-induced plant volatiles (HIPVs) or herbivore chemicals such as pheromones, i.e., chemicals mediating intraspecific communication between herbivores. Natural enem...
Article
The African citrus triozid (ACT), Trioza erytreae, is an important pest of citrus. Both nymphs and adults damage the plant by feeding on the sap causing young shoots to die. Trioza erytreae also vectors Candidatus Liberibacter africanus, the bacteria that cause citrus greening disease. Since certain non‐host plants are known to repel insect pests,...
Article
The predatory African weaver ant, Oecophylla longinoda (Hymenoptera: Formicidae) effectively control pests by predation as well as by semiochemicals which influence the behaviour of certain species. Here, we investigated and compared the role of O. longinoda semiochemicals on the oviposition responses of two major fruit fly (Diptera: Tephritidae) s...
Article
Full-text available
A fundamental understanding of plant sugar feeding behaviour in vector populations can lead to the development of ecologically effective vector monitoring and control strategies. Despite previous studies on mosquito–plant interactions, relatively few have been conducted on the dengue vector Aedes aegypti (Diptera: Culicidae). The authors studied Ae...
Article
Full-text available
The African weaver ant, Oecophylla longinoda, is used as a biological control agent for the management of pests. The ant has several exocrine glands in the abdomen, including Dufour's, poison, rectal, and sternal glands, which are associated with pheromone secretions for intra-specific communication. Previous studies have analyzed the gland secreti...
Article
Full-text available
Natural enemies locate their herbivorous host and prey through kairomones emitted by host plants and herbivores. These kairomones could be exploited to attract and retain natural enemies in crop fields for insect pest control. The parasitoid Encarsia formosa preferentially parasitises its whitefly host, Trialeurodes vaporariorum, a major pest of to...
Article
Cohesion in social insect colonies is maintained by use of chemical signals produced by the queen, workers, and brood. In honey bees in particular, signals from the queen and brood are crucial for the regulation of reproductive division of labor, ensuring that the only reproductive female individual in the colony is the queen, whereas the workers r...
Article
Full-text available
Background In a recent study using DNA barcoding, we identified the plants fed upon by four Afro-tropical mosquito species that vector dengue, malaria, and Rift Valley fever. Herein, we have expanded on this study by investigating the role of three of the plants, Pithecellobium dulce (Fabaceae), Leonotis nepetifolia (Lamiaceae), and Opuntia ficus -...
Article
The honeybee nest parasite Aethina tumida (small hive beetle), uses behavioural mimicry to induce trophallactic feeding from its honeybee hosts. Small hive beetles are able to induce honeybee workers to share the carbohydrate–rich contents of their crops, but it is not clear whether the beetles are able to induce to workers to feed them the protein...
Article
The riverine tsetse fly Glossina fuscipes fuscipes is a major vector of trypanosome pathogens causing African trypanosomiasis. This fly species uses a combination of olfactory and visual cues to locate its hosts. Previously, traps and targets baited with visual cues have been used in vector control, but the development of olfactory-based tools has...
Article
Mounds are prominent architectural features found in savannah ecosystems, where they play important roles. Although constant in form for many species, the appearance and type of mound can vary with environmental conditions such as rainfall, temperature , vegetation and locality. However, variability between mounds of same species in different habit...
Article
Visual and olfactory communication are vital for coordinated group hunting in most animals. To hunt for prey, the group raiding termite specialist ant Megaponera analis, which lacks good vision must first confirm the presence or absence of conspecific raiders. Here we show that, M. analis uses olfactory cues for intra-specific communication and sho...
Article
Full-text available
The socio-economic impacts of COVID-19 on society have yet to be truly revealed; there is no doubt that the pandemic has severely affected the daily lives of most of humanity. It is to be expected that the research activities of scientists could be impacted to varying degrees, but no data exist on how COVID-19 has affected research specifically. He...
Preprint
Full-text available
Background: In a recent study using DNA barcoding, we identified the plants fed upon by four Afro-tropical mosquito species that vector dengue, malaria, and Rift Valley fever. Herein, we have expanded on this study by investigating the role of three of the plants Pithecellobium dulce (Fabaceae), Leonotis nepetifolia (Lamiaceae), and Opuntia ficus-i...
Preprint
Full-text available
Background: In a recent study using DNA barcoding, we identified the plants fed upon by four Afro-tropical mosquito species that vector dengue, malaria, and Rift Valley fever. Herein, we have expanded on this study by investigating the role of three of the plants Pithecellobium dulce (Fabaceae), Leonotis nepetifolia (Lamiaceae), and Opuntia ficus-i...
Preprint
Full-text available
Background: In a recent study using DNA barcoding, we identified the plants fed upon by four Afro-tropical mosquito species that vector dengue, malaria, and Rift Valley fever. Herein, we have expanded on this study by investigating the role of three of the plants Pithecellobium dulce (Fabaceae), Leonotis nepetifolia (Lamiaceae), and Opuntia ficus-i...
Preprint
Full-text available
Background In a recent study using DNA barcoding, we identified the plants fed upon by four Afro-tropical mosquito species that vector dengue, malaria, and Rift Valley fever. Herein, we have expanded on this study by investigating the role of three of the plants Pithecellobium dulce (Fabaceae), Leonotis nepetifolia (Lamiaceae), and Opuntia ficus-in...
Article
Social insects are characterized by the division of labor. Queens usually dominate reproduction, whereas workers fulfill non-reproductive age-dependent tasks to maintain the colony. Although workers are typically sterile, they can activate their ovaries to produce their own offspring. In the extreme, worker reproduction can turn into social parasit...
Article
Adult Mantispidae are general predators of arthropods equipped with raptorial forelegs. The three larval instars display varying degrees of hypermetamorphic ontogeny. The larval stages exhibit a remarkable life history ranging from specialised predators of nest-building hymenopteran larvae and pupa, to specialised predators of spider-eggs, to possi...
Article
The African coffee white stem borer Monochamus leuconotus (Pascoe) (Coleoptera: Cerambycidae) is a destructive insect pest of Arabica coffee trees in African highlands. Our study aims to provide information on the pest biology as influenced by temperature, determine thermal thresholds, and provide life table parameters for M. leuconotus reared in t...
Chapter
African honey bees are those subspecies of the Western honey bee, Apis mellifera, that occur naturally on the African continent and some of the nearby islands. ...
Article
Full-text available
Promoting co-existence between humans and their physical and ecological environment, including wildlife, has been given an increased importance due to a recent shift of society to become environmentally sustainable. However, humans and large carnivores have been in conflict throughout history. One of the most prominent reasons for this conflict is...
Article
Nutritional stress due to habitat transformation and loss is one of several factors contributing to current declines in global bee populations. Bees obtain protein from pollen, which in honeybees is consumed and digested by nurse bees. They then distribute the protein to the rest of the colony in the form of hypopharyngeal gland secretions. Little...
Article
Full-text available
The African citrus triozid, Trioza erytreae Del Guercio (Hemiptera: Triozidae) is one of the primary vectors of the bacterium Candidatus Liberibacter spp. which causes citrus greening, a disease of global economic importance in citrus production. Despite its economic importance, little is known about its chemical ecology. Here, we used behavioral a...
Article
Meiotic recombination is an essential component of eukaryotic sexual reproduction, but its frequency varies within and between genomes. Although it is well established that honey bees have a high recombination rate with about 20 cM/Mbp, the proximate and ultimate causes of this exceptional rate are poorly understood. Here, we describe six linkage m...
Conference Paper
Antestia bugs Antestiopsis spp. (Hemiptera: Pentatomidae) are important insect pests of Arabica coffee in Africa. These pests attack flower buds, shoots, leaves, and green berries leading to both low yields and quality of coffee beans. In East Africa, Antestiopsis thunbergii and A. facetoides were found to co-occur in coffee plantations. However, t...
Article
Termites are known for their abilities to regulate the conditions within their nests through the mounds that they build or the location of the built mound which assist in keeping the internal temperature within the requirement of the colony. These mechanisms to regulate vary between species, with some species adapting passive behaviours such as nes...
Article
Although the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae) is the most destructive insect pest of coffee worldwide, there is much to learn about its thermal biology. This study aimed to develop temperature-based models for H. hampei development and to provide the thermal requirements of immature stages in...
Article
Colony losses due to social parasitism in the form of reproductive workers of the Apis mellifera capensis clones results from the production of queen-like pheromonal signals coupled with ovarian activation in these socially parasitic honey bees. While the behavioral attributes of these social parasites have been described, their genetic attributes...
Article
Full-text available
Background: A blend of compounds (pentanoic acid, guaiacol, δ-octalactone and geranylacetone) identified in waterbuck (Kobus defassa) body odour referred to as waterbuck repellent compounds (WRC) and a synthetic repellent 4-methylguaiacol have previously been shown to repel tsetse flies from the morsitans group. However, these repellents have not...
Article
Full-text available
Background: African trypanosomosis, primarily transmitted by tsetse flies, remains a serious public health and economic challenge in sub-Saharan Africa. Interventions employing natural repellents from non-preferred hosts of tsetse flies represent a promising management approach. Although zebras have been identified as non-preferred hosts of tsetse...
Article
Full-text available
Cape honeybee, Apis mellifera capensis, workers can be social parasites and host colonies can defend themselves by rejection of such workers. Using the pseudo-clonal obligate parasitic lineage of A. m. capensis and wild-type A. m. capensis workers, which are facultative parasites, we show that host colonies significantly increase their defence beha...
Article
Recent studies have emphasized the role of the western honey bee, Apis mellifera, as a managed agricultural species worldwide, but also as a potential threat to endangered wild pollinators. This has resulted in the suggestion that honey bees should be regulated in natural areas to conserve wild pollinators. We argue that this perspective fails to a...
Article
The book is a result of a long on-going collaboration between the two authors. For decades they investigated various aspects of honey bees, in particular the exceptional features of the two honey bee subspecies found in South Africa, namely Apis mellifera capensis and A. m. scutellata. Nevertheless, the book not only focuses on these two iconic Afr...
Article
Hypotrigona species are difficult to identify morphologically. Here, we show that nest sites and nest architecture can be used to discriminate three Hypotrigona species found in Kenya. Hypotrigona gribodoi, H. araujoi and H. ruspolii colonies from Kakamega forest and H. gribodoi from Mwingi, were collected and placed in a meliponiary at the Interna...
Article
The primer and releaser effects of dominant honey bee workers’ tergal gland pheromones are not known under queenless conditions. The Cape honey bee, Apis mellifera capensis, is the ideal model to investigate such question since workers normally reproductively dominate workers of all other subspecies. We determined the effects that short- and long-t...
Article
The evolution of altruism in complex insect societies is arguably one of the major transitions in evolution and inclusive fitness theory plausibly explains why this is an evolutionary stable strategy. Yet, workers of the South African Cape honey bee (Apis mellifera capensis) can reverse to selfish behaviour by becoming social parasites and partheno...
Article
Laboratory experiments are vital to exploring the causes of pollinator loss, but for these experiments to be informative, they should attempt to replicate the hive environment and conserve social interactions. It is unclear how honeybee density and group size affect survival and behaviour in the laboratory. We manipulated cage volume (125–1312 ml)...
Article
Full-text available
The antestia bug, Antestiopsis thunbergii (Gmelin 1790) is a major pest of Arabica coffee in Africa. The bug prefers coffee at the highest elevations, contrary to other major pests. The objectives of this study were to describe the relationship between A. thunbergii populations and elevation, to elucidate this relationship using our knowledge of th...
Article
Full-text available
Social cohesion in social insect colonies can be achieved through the use of chemical signals whose production is caste-specific and regulated by social contexts. In honey bees, queen mandibular gland pheromones (QMP) maintain reproductive dominance by inhibiting ovary activation and production of queen-like mandibular gland signals in workers. We...
Article
One of the responses that honey bee workers can make in the event of queen loss is to develop into false queens. False queens are workers that exhibit both behavioural and physiological traits similar to those of a true queen. However, the presence of more than one false queen in a colony distorts the established hierarchies. As transformation into...
Article
For two decades, neonicotinoid insecticides have been extensively used worldwide. Targeting neuronal receptors, they have deleterious effects on the behaviour and physiology of many of many beneficial as well as harmful insects. Bees are exposed to these insecticides in pollen and nectar while providing pollination services to agricultural crops, a...
Article
Full-text available
Background: Small targets comprising panels of blue and insecticide-treated black netting material each 0.25 × 0.25 m have been shown to attract and kill Glossina fuscipes fuscipes Newstead, 1910 (Diptera: Glossinidae) thereby reducing its population density by over 90% in field trials. However, their attractive ability has not been fully exploite...
Article
Although Varroa destructor is the most serious ecto-parasite to the honeybee, Apis mellifera L., some honeybee populations such as Apis mellifera scutellata in Kenya can survive mite infestations without treatment. Previously, we reported that grooming behaviour could be a potential tolerant mechanism expressed by this honeybee subspecies towards m...