Functions of heteranthery and enantiostyly for wing pollination by pollen-collecting bees in Dilatris ixioides (Haemodoraceae).

Background And Aims: Evolutionary floral modifications that enable plants to exploit particular body parts of animals for pollen transfer are considered a key contributor to the angiosperm radiation. Species of Dilatris (Haemodoraceae) have an unusual combination of floral traits including a centrally-positioned stamen with a large anther flanked by two stamens with smaller anthers (heteranthery), and styles that are deflected either to the right or left on flowers of the same plant (monomorphic enantiostyly). We investigated the pollination functions of these traits in D.

A passive blood separation sensing platform for point-of-care devices.

The blood test is one of the most performed investigations in clinical practice, with samples typically analysed in a centralised laboratory. Many of these tests monitor routine conditions that would benefit from a point-of-care approach, reducing the burden on practitioners, patients and healthcare systems. Such a decentralised model requires the development of sophisticated, yet easy-to-use technology; however, platforms that combine high-performance with low-cost and simplicity remain scarce.

Geographical variation in flower colour of a food-deceptive orchid reflects local pollinator preferences.

Background And Aims: Intraspecific variation in floral traits can reflect shifts among different pollinator niches. We investigated whether a geographical mosaic of pollinator niches can explain divergence of flower colour and morphology among populations of Disa porrecta, a food-deceptive orchid in South Africa.

Methods: We used field observations and pollen load analysis to establish pollinators of D.

Characterising the performance of a drone-mounted real-time methane imaging system.

We demonstrate a methane gas imaging system mounted to an unmanned aerial vehicle (UAV) that is shown to perform real-time detection at distances up to 10m whist airborne. Laser diodes that switch between on- and off- resonance with a methane absorption line are used to flood-illuminate a scene. The scene is imaged with an infrared InGaAs camera and the differential of the on-resonance and off-resonance back-scatter images are used to reveal the gas distribution.

Pollination ecotypes and the origin of plant species.

Ecological niche shifts are a key driver of phenotypic divergence and contribute to isolating barriers among lineages. For many groups of organisms, the history of these shifts and associated trait-environment correlations are well-documented at the macroevolutionary level. However, the processes that generate these patterns are initiated below the species level, often by the formation of ecotypes in contrasting environments.

Pollination efficiency and the evolution of sex allocation - diminishing returns matter.

Immobility of flowering plants requires them to engage pollen vectors to outcross, introducing considerable inefficiency in the conversion of pollen production into sired seeds. Whether inefficiencies influence the evolution of the relative resource allocation to female and male functions has been debated for more than 40 years. Whereas early models suggested no effect, negative interspecific relations of mean pollen production and pollen : ovule ratios to the proportion of removed pollen that is exported to stigmas (pollen-transfer efficiency) indicate otherwise.

FlowerMate: Multidimensional reciprocity and inaccuracy indices for style-polymorphic plant populations.

Premise: Heterostyly in plants promotes pollen transfer between floral morphs, because female and male sex organs are located at roughly reciprocal heights within the flowers of each morph. Reciprocity indices, which assess the one-dimensional variation in the height of sex organs, are used to define the phenotypic structure of heterostyly in plant populations and to make inferences about selection. Other reciprocal stylar polymorphisms (e.

Pollinator-mediated isolation promotes coexistence of closely related food-deceptive orchids.

Identifying the factors that contribute to reproductive isolation among closely related species is key for understanding the diversification of lineages. In this study, we investigate the strength of premating and postmating reproductive isolation barriers between Disa ferruginea and Disa gladioliflora, a pair of closely related species, often found co-flowering in sympatry. Both species are non-rewarding and rely on mimicry of different rewarding model flowers for the attraction of pollinators.

Scent-mediated bee pollination and myrmecochory in an enigmatic geophyte with pyrogenic flowering and subterranean development of fleshy fruits.

Premise: Volatile emissions from flowers and fruits play a key role in signalling to animals responsible for pollination and seed dispersal. Here, we investigated the pollination biology and chemical ecology of reproduction in Apodolirion buchananii, an African amaryllid that flowers in a leafless state soon after grassland vegetation is burnt in the dry late-winter season.

Methods: Pollinators were identified through field collection and pollen loads were quantified.

Flowers meet Newton: testing the role of gravitational pull in resupination of orchid flowers.

Resupination refers to the developmental orientation changes of flowers through ~180°, leaving them effectively upside-down. It is a widespread trait present in 14 angiosperm families, including the Orchidaceae, where it is a gravitropic phenomenon actively controlled by auxins. Here, we demonstrate that the passive gravitational pull on flower parts can have an additional influence on resupination.

Pollen transfer efficiency in depends on type of pollinator.

Pollen transfer efficiency (PTE; the proportion of pollen removed from flowers that reaches conspecific stigmas) is expected to vary with the type of pollinator and flower morphology, and to influence male siring success. Many species in the genus are pollinated by bees (which consume pollen and should thus lower PTE) but during its radiation in the Cape, several independent shifts to both sunbird and long-proboscid fly (LP fly) pollinators, which do not consume pollen have taken place. Improvements in PTE could be one of the factors driving these pollinator shifts.

Noise Tolerant Photonic Bowtie Grating Environmental Sensor.

Resonant photonic refractive index sensors have made major advances based on their high sensitivity and contact-less readout capability, which is advantageous in many areas of science and technology. A major issue for the technological implementation of such sensors is their response to external influences, such as vibrations and temperature variations; the more sensitive a sensor, the more susceptible it also becomes to external influences. Here, we introduce a novel bowtie-shaped sensor that is highly responsive to refractive index variations while compensating for temperature changes and mechanical (linear and angular) vibrations.

Convergent evolutionary patterns of heterostyly across angiosperms support the pollination-precision hypothesis.

Since the insights by Charles Darwin, heterostyly, a floral polymorphism with morphs bearing stigmas and anthers at reciprocal heights, has become a model system for the study of natural selection. Based on his archetypal heterostylous flower, including regular symmetry, few stamens and a tube, Darwin hypothesised that heterostyly evolved to promote outcrossing through efficient pollen transfer between morphs involving different areas of a pollinator's body, thus proposing his seminal pollination-precision hypothesis. Here we update the number of heterostylous and other style-length polymorphic taxa to 247 genera belonging to 34 families, notably expanding known cases by 20%.

Nectar cardenolides and floral volatiles mediate a specialized wasp pollination system.

Specialization in plant pollination systems can arise from traits that function as filters of flower visitors. This may involve chemical traits such as floral volatiles that selectively attract favoured visitors and non-volatile nectar constituents that selectively deter disfavoured visitors through taste or longer-term toxic effects or both. We explored the functions of floral chemical traits in the African milkweed Gomphocarpus physocarpus, which is pollinated almost exclusively by vespid wasps, despite having nectar that is highly accessible to other insects such as honeybees.

The economy of pollen dispersal in flowering plants.

Mating success of flowering plants depends strongly on the efficiencies of pollen removal from flowers and its subsequent dispersal to conspecific stigmas. We characterized the economy of pollen dispersal in flowering plants by analysing pollen fates and their correlates for 228 species. The mean percentage of pollen removed from flowers (removal efficiency) varied almost twofold according to the type of pollen-dispersal unit, from less than 45% for orchids and milkweeds with solid pollinia, to greater than 80% for species with granular monads or sectile (segmented) pollinia.

Effect of fuchsin fixation of pollen on DNA barcode recovery.

Pollen grains attached to insects are a valuable source of ecological information which can be used to reconstruct visitation networks. Morphological pollen identification relies on light microscopy with pollen usually stained and mounted in fuchsin jelly, which is also used to remove pollen from the bodies of insects. Pollen embedded in fuchsin jelly could potentially be used for DNA barcoding and metabarcoding (large-scale taxonomic identification of complex mixed samples) and thus provide additional information for pollination networks.

The enantiostylous floral polymorphism of Barberetta aurea (Haemodoraceae) facilitates wing pollination by syrphid flies.

Background And Aims: Sexual polymorphisms of flowers have traditionally been interpreted as devices that promote cross-pollination, but they may also represent adaptations for exploiting particular pollination niches in local environments. The cross-pollination function of enantiostyly, characterized by flowers having either left- or right-deflected styles, has been uncertain in some lineages, such as the Haemodoraceae, because the positioning of stamens and styles is not always completely reciprocal among morphs.

Methods: We examined the floral biology of populations of the poorly known species Barberetta aurea (Haemodoraceae) across its native range in South Africa to establish the general features of its enanatiostylous reproductive system and the agents and mechanism of pollen transfer.

Steven D. Johnson.

Interview with Steve Johnson, who works on plant-pollinator interactions at the University of KwaZulu-Natal in South Africa.

Beyond pollen:ovule ratios: Evolutionary consequences of pollinator dependence and pollination efficiency for pollen and ovule production in angiosperms.

Premise: The relative per-flower production of ovules and pollen varies broadly with angiosperm mating systems, with outcrossing types commonly producing more pollen grains per ovule than selfing types. The evolutionary causes of this variation are contentious, especially the relevance of pollination risk. Resolution of this debate may have been hampered by its focus on pollen:ovule (P:O) ratios rather than on the evolution of pollen and ovule numbers per se.

'Bleeding' flowers of Ceropegia gerrardii (Apocynaceae-Asclepiadoideae) mimic wounded insects to attract kleptoparasitic fly pollinators.

Kleptomyiophily, where flowers imitate wounded insects to attract 'kleptoparasitic' flies as pollinators, is one of the most specialized types of floral mimicry and often involves physical trapping devices. However, the diversity of pollinators and functional floral traits involved in this form of mimicry remain poorly understood. We report a novel example of kleptomyiophily in the nontrapping flowers of Ceropegia gerrardii and explore the floral traits responsible for attracting pollinators.

The lady's 'slippery' orchid: functions of the floral trap and aphid mimicry in a hoverfly-pollinated Phragmipedium species in Brazil.

Background And Aims: Trap flowers are fascinating cases of adaptation, often linked to oviposition-site mimicry systems. Some trap flowers do not imprison pollinators for a pre-determined period, but rather force them to move through a specific path, manipulating their movements in a way that culminates in pollen transfer, often as they leave through a secondary opening.

Methods: We investigated the previously unknown pollination system of the lady's slipper orchid Phragmipedium vittatum and assessed the function of micro-morphological traits of its trap flowers.

Bird pollination.

Johnson gives an overview of bird pollinators and the plant species they pollinate.

Antibiotic-functionalized gold nanoparticles for the detection of active β-lactamases.

Antimicrobial resistance (AMR) continues to threaten the effective treatment and prevention of bacterial infections. The spread of resistant infections is accelerated by the lack of fast and cost-effective tests for the detection of AMR at the point-of-care. We aimed to address this challenge by developing a diagnostic tool to detect one of the major forms of AMR, the β-lactamase enzymes.

Why honeybees are poor pollinators of a mass-flowering plant: Experimental support for the low pollen quality hypothesis.

Premise: Honeybees dominate the flower-visitor assemblages of many plant species, yet their efficiency in terms of the quality of pollen delivered to stigmas is largely unknown. We investigated why honeybees are poor pollinators of Aloe ferox, a self-incompatible succulent treelet with large numbers of flowers. Honeybees are very frequent visitors to flowers of this species, yet contribute very little to seed production.