Hawkmoth pollination of the orchid Habenaria clavata: mechanical wing guides, floral scent and electroantennography

2019 ◽  
Author(s):  
Steven D Johnson ◽  
Marco G Balducci ◽  
Adam Shuttleworth
Keyword(s):  
Spectral Reflectance ◽  
Floral Morphology ◽  
Floral Scent ◽  
Ventral Surface ◽  
Multiple Traits ◽  
Video Cameras ◽  
Reproductive Structures ◽  
Electrophysiological Responses ◽  
Hawkmoth Pollination ◽  
Frequent Visitor

Abstract Floral morphology can play a key role in mechanically guiding pollinators towards reproductive structures, particularly when visibility is limited at night, but the functional significance of morphological traits has seldom been considered in this context. Here we describe a remarkably intricate pollination mechanism in the hawkmoth-pollinated African grassland orchid Habenaria clavata, and also document aspects of the reproductive success and chemical ecology of this pollination system. The flowers are pollinated by several short-tongued hawkmoths, particularly Basiothia schenki, which was the most frequent visitor and occurred at all sites. Moths are probably attracted by the strong scent, which was dominated by several oxygenated aromatics that also elicited strong electrophysiological responses from antennae of B. schenki. Apart from the white rostellum lobes and stigma, which serve as a visual guide to the spur entrance, the flower parts are entirely green and indistinguishable from leaves in terms of spectral information. Using motion-activated video cameras we established that the leading edges of the forewings of foraging hawkmoths contact the two upwardly curving petal lobes, and that hawkmoths are then apparently mechanically guided down onto the reproductive structures. Pollinaria are attached in an unusual place – among hairs on the ventral surface of the thorax, between the middle legs – and are brushed over the protruding stigma lobes when the proboscis is fully inserted in the 41-mm-long spur. These results highlight how multiple traits (morphology, spectral reflectance and scent) can act synergistically to ensure transfer of pollen among flowers.

scholarly journals Review of the Capsalinae (Monogenea: Capsalidae)

Zootaxa ◽  
2007 ◽  
Vol 1559 (1) ◽  
pp. 1-30 ◽  
Author(s):  
LESLIE A. CHISHOLM ◽  
IAN D. WHITTINGTON
Keyword(s):  
Ventral Surface ◽  
Current Concept ◽  
Specimen Preparation ◽  
Reproductive Structures ◽  
The Status ◽  
Voucher Specimens ◽  
Preparation Techniques ◽  
Species Inquirendae

The Capsalinae Baird, 1853 (Monogenea: Capsalidae) is revised based on a thorough review of original descriptions and examination of type museum material, where available, to validate species. A total of 262 type and voucher specimens was studied representing apparently 42 of the 60 currently described capsaline species. A combination of characters that should be independent of variation due to specimen preparation techniques was chosen to discriminate species. These characters include the presence/absence of papillae on the ventral surface of the haptor, the presence/absence and the morphology of haptoral accessory sclerites and the presence/absence of dorsomarginal body sclerites and their morphology and distribution. We consider that only 36 of the 60 nominal capsaline species are valid. We could find no support for Caballerocotyla Price, 1960 and therefore we synonymise it with Capsala Bosc, 1811. Under the current concept we recognise 22 species of Capsala, 7 species of Capsaloides Price, 1938, 3 species of Nasicola Yamaguti, 1968 and 4 species of Tristoma Cuvier, 1817. The following Capsala species are considered valid: C. albsmithi (Dollfus, 1962) n. comb.; C. biparasitica (Goto, 1894) Price, 1938; C. caballeroi Winter, 1955; C. foliacea (Goto, 1894) Price, 1938; C. gouri Chauhan, 1951; C. gregalis (Wagner & Carter, 1967) n. comb.; C. interrupta (Monticelli, 1891) Johnston, 1929; C. katsuwoni (Ishii, 1936) Price, 1938; C. laevis (Verrill, 1875) Johnston, 1929; C. maccallumi Price, 1939; C. magronum (Ishii, 1936) Price, 1938; C. manteri Price, 1951; C. manteriaffinis (Mamaev, 1968) n. comb.; C. martinierei Bosc, 1811; C. notosinense (Mamaev, 1968) n. comb.; C. nozawae (Goto, 1894) Price, 1938; C. onchidiocotyle (Setti, 1899) Johnston, 1929; C. ovalis (Goto, 1894) Price, 1938; C. paucispinosa (Mamaev, 1968) n. comb.; C. pelamydis (Taschenberg, 1878) Price, 1938; C. poeyi (Pérez-Vigueras, 1935) Price, 1938; C. pricei Hildago-Escalente, 1950. We consider the following Capsaloides species valid: C. cornutus (Verrill, 1875) Price, 1938; C. cristatus Yamaguti, 1968; C. hoffmannae Lamothe-Argumedo, 1996; C. magnaspinosus Price, 1939; C. nairagi Yamaguti, 1968; C. perugiai (Setti, 1898) Price, 1938; C. sinuatus (Goto, 1894) Price, 1938. The following Nasicola species are deemed valid: N. brasiliensis Kohn, Baptista-Farias, Santos & Gibson, 2004; N. hogansi Wheeler & Beverley-Burton, 1987; N. klawei Stunkard, 1962. Presently, we consider the following Tristoma species valid: T. adcoccineum Yamaguti, 1968; T. adintegrum Yamaguti, 1968; T. coccineum Cuvier, 1817; T. integrum Diesing, 1850. A list of new and re-established synonyms is provided. The status of each species is discussed in detail and a key to all capsaline species that we consider valid is presented. The following 5 capsaline species are considered to be species inquirendae: Caballerocotyla phillippina Velasquez, 1982; Capsala megacotyle (Linstow, 1906) Johnston, 1929; Tristoma fuhrmanni Guiart, 1938; T. levinsenii Monticelli, 1891; T. uncinatum Monticelli, 1889. The importance of careful character selection to discriminate between capsaline species and the need for studies of live parasites to obtain additional characters based on reproductive structures is addressed. Hostspecificity in the Capsalinae is also discussed.

scholarly journals A Review on the Pollination of Aroids with Bisexual Flowers

2019 ◽  
Vol 104 (1) ◽  
pp. 83-104 ◽  
Author(s):  
Pedro Díaz Jiménez ◽  
Heiko Hentrich ◽  
Pedro Adrián Aguilar-Rodríguez ◽  
Thorsten Krömer ◽  
Marion Chartier ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Volatile Compounds ◽  
Floral Morphology ◽  
Current Knowledge ◽  
Floral Scent ◽  
Sympatric Species ◽  
Floral Ecology ◽  
Floral Visitors ◽  
Floral Volatile ◽  
Pollination Systems

This paper presents an exhaustive review of the current knowledge on pollination of Araceae genera with bisexual flowers. All available studies on floral morphology, flowering sequence, floral scent, floral thermogenesis, floral visitors, and pollinators were carefully examined, with emphasis on the species-rich genera Anthurium Schott, Monstera Adans., and Spathiphyllum Schott. Genera with bisexual flowers are among the early-diverging lineages in Araceae, but present adaptations in their floral ecology to a great variety of pollination vectors, such as bees, beetles, flies, and, unusually, wind. These clades have developed highly derived pollination systems, involving the use of floral scent as a reward. We conclude that floral scent chemistry plays a key role in the pollination biology of the plants and that, in some genera, reproductive isolation through variation in the emitted floral volatile compounds may have been the decisive factor in the speciation processes of sympatric species.

Improved 3-D reconstruction using stereo computer graphics and multiple tilt EM images

1995 ◽  
Vol 53 ◽  
pp. 630-631
Author(s):  
Lee D. Peachey ◽  
Lou Fodor ◽  
John C. Haselgrove ◽  
Stanley M. Dunn ◽  
Junqing Huang
Keyword(s):  
Computer Graphics ◽  
High Performance ◽  
Transverse Section ◽  
Three Dimensional ◽  
Stereo Pair ◽  
3D Reconstructions ◽  
Video Cameras ◽  
Biological Objects ◽  
Microscope Images ◽  
High Performance Computer

Stereo pairs of electron microscope images provide valuable visual impressions of the three-dimensional nature of specimens, including biological objects. Beyond this one seeks quantitatively accurate models and measurements of the three dimensional positions and sizes of structures in the specimen. In our laboratory, we have sought to combine high resolution video cameras with high performance computer graphics systems to improve both the ease of building 3D reconstructions and the accuracy of 3D measurements, by using multiple tilt images of the same specimen tilted over a wider range of angles than can be viewed stereoscopically. Ultimately we also wish to automate the reconstruction and measurement process, and have initiated work in that direction.Figure 1 is a stereo pair of 400 kV images from a 1 micrometer thick transverse section of frog skeletal muscle stained with the Golgi stain. This stain selectively increases the density of the transverse tubular network in these muscle cells, and it is this network that we reconstruct in this example.

Scanning electron microscopy of the integument of schistosoma rodhaini

1986 ◽  
Vol 44 ◽  
pp. 132-133
Author(s):  
P. Evers ◽  
C. Schutte ◽  
C. D. Dettman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Oral Sucker ◽  
Adult Male ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Sensory Receptors ◽  
East African ◽  
Dorsal Midline ◽  
Scanning Electron

S.rodhaini (Brumpt 1931) is a parasite of East African rodents which may possibly hybridize with the human schistosome S. mansoni. The adult male at maturity measures approximately 3mm long and possesses both oral and ventral suckers and a marked gynaecophoric canal. The oral sucker is surrounded by a ring of sensory receptors with a large number of inwardly-pointing spines set into deep sockets occupying the bulk of the ventral surface of the sucker. Numbers of scattered sensory receptors are found on both dorsal and ventral surfaces of the head (Fig. 1) together with two conspicuous rows of receptors situated symmetrically on each side of the midline. One row extends along the dorsal surface of the head midway between the dorsal midline and the lateral margin.

Freeze substitution fixation of fungal reproductive structures and spores

1989 ◽  
Vol 47 ◽  
pp. 990-991
Author(s):  
C. W. Mims ◽  
E. A. Richardson
Keyword(s):  
Plant Pathogens ◽  
Freeze Substitution ◽  
Uranyl Acetate ◽  
Chemical Fixation ◽  
Dialysis Membrane ◽  
Razor Blade ◽  
Thin Sections ◽  
Reproductive Structures ◽  
Dry Down ◽  
Diamond Knife

The advantages of freeze substitution fixation over conventional chemical fixation for preservation of ultrastructural details in fungi have been discussed by various authors. As most ascomycetes, basidiomycetes and deuteromycetes do not fix well using conventional chemical fixation protocols, freeze substitution has attracted the attention of many individuals interested in fungal ultrastructure. Thus far most workers using this technique on fungi have concentrated on thin walled somatic hyphae. However, in our laboratory we have experimented with the use of freeze substitution on a variety of fungal reproductive structures and spores with promising results.Here we present data on freeze substituted samples of sporangia of the zygomycete Umbellopsis vinacea, basidia of Exobasidium camelliae var. gracilis, developing teliospores of the smut Sporisorium sorghi, germinating teliospores of the rust Gymnosporangium clavipes, germinating conidia of the deuteromycete Cercosporidium personatum, and developing ascospores of Ascodesmis nigricans.Spores of G. clavipes and C. personatum were deposited on moist pieces of sterile dialysis membrane where they hydrated and germinated. Asci of A. nigricans developed on pieces of dialysis membrane lying on nutrient agar plates. U. vinacea was cultured on small pieces of agar-coated wire. In the plant pathogens E. camelliae var. gracilis and S. sorghi, a razor blade was used to remove smal1 pieces of infected host issue. All samples were plunged directly into liquid propane and processed for study according to Hoch.l Samples on dialysis membrane were flat embedded. Serial thin sections were cut using a diamond knife, collected on slot grids, and allowed to dry down onto Formvar coated aluminum racks. Sections were post stained with uranyl acetate and lead citrate.

The Involuntary Capture of Attention by Sound

2010 ◽  
Vol 57 (1) ◽  
pp. 68-76 ◽  
Author(s):  
Fabrice B. R. Parmentier ◽  
Pilar Andrés
Keyword(s):  
Older Adults ◽  
Mismatch Negativity ◽  
Visual Task ◽  
The Novel ◽  
Auditory Oddball ◽  
Current Trial ◽  
Electrophysiological Responses ◽  
Electrophysiological Studies ◽  
The Cross ◽  
Task Sets

The presentation of auditory oddball stimuli (novels) among otherwise repeated sounds (standards) triggers a well-identified chain of electrophysiological responses: The detection of acoustic change (mismatch negativity), the involuntary orientation of attention to (P3a) and its reorientation from the novel. Behaviorally, novels reduce performance in an unrelated visual task (novelty distraction). Past studies of the cross-modal capture of attention by acoustic novelty have typically discarded from their analysis the data from the standard trials immediately following a novel, despite some evidence in mono-modal oddball tasks of distraction extending beyond the presentation of deviants/novels (postnovelty distraction). The present study measured novelty and postnovelty distraction and examined the hypothesis that both types of distraction may be underpinned by common frontally-related processes by comparing young and older adults. Our data establish that novels delayed responses not only on the current trial and but also on the subsequent standard trial. Both of these effects increased with age. We argue that both types of distraction relate to the reconfiguration of task-sets and discuss this contention in relation to recent electrophysiological studies.

2D Color-Intensity Representation of Ultrasonic Thickness Gauge Measurements

2020 ◽  
pp. 1192-1198
Author(s):  
M.S. Mohammad ◽  
Tibebe Tesfaye ◽  
Kim Ki-Seong
Keyword(s):  
Cost Effective ◽  
The Other ◽  
Thickness Gauge ◽  
Color Intensity ◽  
Digital Readout ◽  
Flat Surfaces ◽  
Video Cameras ◽  
Wide Range ◽  
Cost Effective Alternative ◽  
Ultrasonic Thickness

Ultrasonic thickness gauges are easy to operate and reliable, and can be used to measure a wide range of thicknesses and inspect all engineering materials. Supplementing the simple ultrasonic thickness gauges that present results in either a digital readout or as an A-scan with systems that enable correlating the measured values to their positions on the inspected surface to produce a two-dimensional (2D) thickness representation can extend their benefits and provide a cost-effective alternative to expensive advanced C-scan machines. In previous work, the authors introduced a system for the positioning and mapping of the values measured by the ultrasonic thickness gauges and flaw detectors (Tesfaye et al. 2019). The system is an alternative to the systems that use mechanical scanners, encoders, and sophisticated UT machines. It used a camera to record the probe’s movement and a projected laser grid obtained by a laser pattern generator to locate the probe on the inspected surface. In this paper, a novel system is proposed to be applied to flat surfaces, in addition to overcoming the other limitations posed due to the use of the laser projection. The proposed system uses two video cameras, one to monitor the probe’s movement on the inspected surface and the other to capture the corresponding digital readout of the thickness gauge. The acquired images of the probe’s position and thickness gauge readout are processed to plot the measured data in a 2D color-coded map. The system is meant to be simpler and more effective than the previous development.

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