A5023847943- Plant and animal studies
- Plant Parasitism and Resistance
- Ecology and Vegetation Dynamics Studies
- Plant Diversity and Evolution
- Plant Reproductive Biology
- Plant and Fungal Species Descriptions
- Botany, Ecology, and Taxonomy Studies
- Advanced Neuroimaging Techniques and Applications
- Botany and Plant Ecology Studies
- Plant Physiology and Cultivation Studies
- Advanced MRI Techniques and Applications
- African Botany and Ecology Studies
- Species Distribution and Climate Change
- Rangeland and Wildlife Management
- Historical and Archaeological Studies
- Mediterranean and Iberian flora and fauna
- Bee Products Chemical Analysis
- Botanical Research and Applications
- Functional Brain Connectivity Studies
- Plant nutrient uptake and metabolism
- Plant Molecular Biology Research
- Genetic diversity and population structure
- Chemical synthesis and alkaloids
- Lichen and fungal ecology
- Geology and Paleoclimatology Research
Rhodes University
2015-2025
Vanderbilt University Medical Center
2024
University of KwaZulu-Natal
2003-2013
'Pollination syndromes' are suites of phenotypic traits hypothesized to reflect convergent adaptations flowers for pollination by specific types animals. They were first developed in the 1870s and honed during mid 20th Century. In spite this long history their central role organizing research on plant–pollinator interactions, syndromes have rarely been subjected test. The tested here asking whether they successfully capture patterns covariance floral predict most common pollinators flowers....
It has been debated whether pollination success in nonrewarding plants that flower association with nectar-producing will be diminished by competition for pollinator visits or, alternatively, enhanced through increased local abundance of pollinators (the magnet species effect). We experimentally evaluated these effects using the bumblebee-pollinated orchid Anacamptis morio and associated at a site Sweden. Pollination (estimated as pollen receipt removal) A. was significantly greater...
Abstract Orchidaceae show remarkable diversity in pollination strategies, but how these strategies vary globally is not entirely clear. To identify regions and taxa that are data-rich lend themselves to rigorous analyses or data-poor need attention, we introduce a global database of orchid reproductive biology. Our contains > 2900 species representing all subfamilies 23 24 tribes. We tabulated information on habit, breeding systems, means pollinator attraction the identity...
Plants that lack floral rewards can attract pollinators if they share attractive signals with rewarding plants. These deceptive plants should benefit from flowering in close proximity to such plants, because are locally conditioned on of the (mimic effect) and more abundant (magnet effect). We tested these ideas using non-rewarding South African plant Eulophia zeyheriana (Orchidaceae) as a study system. Field observations revealed E. is pollinated solely by solitary bees belonging single...
Large clades of angiosperms are often characterized by diverse interactions with pollinators, but how these pollination systems structured phylogenetically and biogeographically is still uncertain for most families. Apocynaceae a clade >5300 species worldwide distribution. A database representing >10 % in the family was used to explore diversity pollinators evolutionary shifts across major regions. The compiled from published unpublished reports. Plants were categorized into broad then...
It has been suggested that the absence of floral rewards in many orchid species causes pollinators to probe fewer flowers on a plant, and thus reduces geitonogamy, i.e. self-pollination between flowers, which may result inbreeding depression reduced pollen export. We examined effects nectar addition pollinator visitation transfer by tracking fate colour-labelled Anacamptis morio, non-rewarding pollinated primarily queen bumble-bees. Addition spurs A. morio significantly increased number...
Floral diversification driven by shifts between pollinators has been one of the key explanations for radiation angiosperms. According to Grant–Stebbins model pollinator-driven speciation, these result in morphologically distinct 'ecotypes' which may eventually become recognizable as species. The current circumscription food-deceptive southern African orchid Eulophia parviflora encompasses a highly variable monophyletic species complex. In this study, two forms were identified within complex...
Summary Pollinators are thought to play a key role in driving incipient speciation within the angiosperms. However, mechanisms underlying floral divergence plants with generalist pollination systems, remains understudied. Brunsvigia gregaria displays significant geographical variation traits and visited by diverse pollinator communities. Because pollinators often shared between populations, we investigated whether specific responsible for them. Three distinct ecotypes were identified, each...
Introduction The terrestrial orchid genus Nervilia is diagnosed by its hysteranthous pattern of emergence but nested among leafless myco-heterotrophic lineages in the lower Epidendroideae. Comprising ca. 80 species distributed across Africa, Asia and Oceania, remains poorly known plagued vague overlapping circumscriptions, especially within each a series taxonomically intractable complexes. Prior small-scale, exploratory molecular phylogenetic analyses have revealed existence cryptic...
Bowl-shaped inflorescences, geoflory, dull-coloured flowers and winter flowering suggest that Protea foliosa is adapted for rodent-pollination. To test this hypothesis, rodents were trapped in a large P. population near Grahamstown examined the presence of pollen on their snouts scats. Camera traps, modified focus (< 50 cm) by addition close-up filters, used to record mammal visits inflorescences situ. Two rodent species, Rhabdomys pumilio Otomys irroratus, species shrew, Crocidura cyanea,...
Studying flower colour evolution can be challenging as it may require several different areas of expertise, ranging from botany and ecology through to understanding sensing insects thus how they perceive signals. Whilst studies often view plant-pollinator interactions the plant's perspective, there is growing evidence psychophysics that pollinators have their own complex decision making processes depending on perception colour, viewing conditions individual experience. Mimicry rewarding...
Pollen fates strongly influence mating success in plants but are difficult to quantify. By promoting foraging constancy pollinators, floral rewards such as nectar may enhance the overall efficiency of pollen transfer. However, this can also lead high levels geitonogamy. were studied Acrolophia cochlearis, a member terrestrial epidendroid orchid genus that includes both rewarding and deceptive species. Pollinator observations conducted. transfer (PTE), proportion removed pollinia deposited on...
In his landmark work on the pollination biology of South African plants in 1954, Stefan Vogel described deposition Habenaria epipactidea (= H. polyphylla ) pollinaria forelegs hawkmoth Hippotion celerio . The discovery a large, well-pollinated population Eastern Cape allowed us to confirm presence this unusual pollen placement number species shorter-tongued hawkmoths. long-tongued Agrius convolvuli is likely function as nectar thief length tongue relative spur ensures that are unlikely come...
Abstract It has been suggested that plants are good colonizers will generally have either an ability to self‐fertilize or a generalist pollination system. This prediction is based on the idea these reproductive traits should confer resistance Allee effects in founder populations and was tested using Gomphocarpus physocarpus (Asclepiadoideae: Apocynaceae), species native South Africa invasive other parts of world. We found no significant relationships between size G. various measures success...
Mating success in plants depends largely on the efficiency of pollen dispersal. For hermaphrodite plants, self-pollination, either within or among flowers, can reduce mating opportunities because and ovule discounting inbreeding depression. Self-pollination may be particularly detrimental such as orchids asclepiads that package each flower's into one more pollinia which, together with accessory structures, comprise a pollinarium. Darwin proposed physical reconfiguration pollinaria serves...
Autonomous self-pollination is surprisingly common among orchids and thought to provide reproductive assurance when pollinators are scarce. During investigations of the biology orchid genus Eulophia, consistently high rates capsule set were observed in Eulophia clavicornis var. clavicornis, E. c. inaequalis, nutans tenella. A breeding system experiment showed that capable autonomous self-pollination. Emasculated flowers this taxon did not fruit, suggesting agamospermy unlikely. The likely...
Non-rewarding plants use a variety of ruses to attract their pollinators. One the least understood these is generalized food deception, in which flowers exploit non-specific food-seeking responses Available evidence suggests that colour signals, scent and phenology may all play key roles this form deception. Here we investigate pollination systems five Eulophia spp. (Orchidaceae) lacking floral rewards. These species are pollinated by bees, notably Xylocopa (Anthophorinae, Apidae) or...
Abstract Phylogenetic relationships were inferred for the African‐centred orchid subtribe Eulophiinae, which includes large genus Eulophia and three closely related genera, Oeceoclades , Pteroglossaspis Acrolophia . We sequenced one nuclear (ITS) four chloroplast ( rbcL trnK‐matK rpl32‐trnL trnQ‐5′ rps16 ) markers 86 samples, representing 58 species (62 taxa) outgroup. The combined sequence matrix had 6525 characters was analysed using parsimony Bayesian criteria. Our results show that are...
Background and aimsSuccessful invasive plants such as Araujia sericifera usually either are capable of automatic self-pollination or maintain pollinator services by having generalized pollination systems to make use local pollinators in the invaded range. Alternatively, must co-opt new with similar morphology native reproduce asexually. We aimed document biology A. South Africa. Given success this species an invader, we predicted that sexual reproduction occurs through because has...