Studies on the biting habits of East African mosquitos in the genera Uranotaenia, Ficalbia and Hodgesia

1963 ◽  
Vol 53 (4) ◽  
pp. 639-652 ◽  
Author(s):  
A. J. Haddow ◽  
Yovani Ssenkubuge
Keyword(s):  
Light Intensity ◽  
Forest Floor ◽  
Lower Intensity ◽  
East African ◽  
Dense Vegetation ◽  
Biting Behaviour

Mosquitos in the genera Uranotaenia and Ficalbia seldom bite man. In Africa, only two species, U. alboabdominalis Theo. and F. plumosa, (Theo.), have been taken actually engorging on man, though others may occasionally alight on the skin.Hodgesia cyptopus Theo. bites man freely in forest, bush and plantations near Entebbe, Uganda, and sometimes enters houses.The bimodal nature of the biting cycle of H. cyptopus in certain series of catches led to an investigation of the daily march of light intensity near the forest floor. It was found that at least in some areas this is bimodal, with a midday period of lower intensity—a pattern reflected in the biting behaviour of various forest mosquitos.Though always diurnal, the biting cycle of H. cyptopus varies in form from station to station. It is thought that light intensity is of importance, and that this species probably bites in or around the small splashes of sunlight which penetrate the dense vegetation.

scholarly journals Adaptive-illumination STED nanoscopy

2017 ◽  
Vol 114 (37) ◽  
pp. 9797-9802 ◽  
Author(s):  
Jörn Heine ◽  
Matthias Reuss ◽  
Benjamin Harke ◽  
Elisa D’Este ◽  
Steffen J. Sahl ◽  
...  
Keyword(s):  
Light Intensity ◽  
Biological Imaging ◽  
The State ◽  
Lower Intensity ◽  
2D And 3D ◽  
Imaging Conditions ◽  
State Difference

The concepts called STED/RESOLFT superresolve features by a light-driven transfer of closely packed molecules between two different states, typically a nonfluorescent “off” state and a fluorescent “on” state at well-defined coordinates on subdiffraction scales. For this, the applied light intensity must be sufficient to guarantee the state difference for molecules spaced at the resolution sought. Relatively high intensities have therefore been applied throughout the imaging to obtain the highest resolutions. At regions where features are far enough apart that molecules could be separated with lower intensity, the excess intensity just adds to photobleaching. Here, we introduce DyMIN (standing for Dynamic Intensity Minimum) scanning, generalizing and expanding on earlier concepts of RESCue and MINFIELD to reduce sample exposure. The principle of DyMIN is that it only uses as much on/off-switching light as needed to image at the desired resolution. Fluorescence can be recorded at those positions where fluorophores are found within a subresolution neighborhood. By tuning the intensity (and thus resolution) during the acquisition of each pixel/voxel, we match the size of this neighborhood to the structures being imaged. DyMIN is shown to lower the dose of STED light on the scanned region up to ∼20-fold under common biological imaging conditions, and >100-fold for sparser 2D and 3D samples. The bleaching reduction can be converted into accordingly brighter images at <30-nm resolution.

A Method for Measuring Light Intensity Under Dense Vegetation

Ecology ◽  
1968 ◽  
Vol 49 (6) ◽  
pp. 1168-1169 ◽  
Author(s):  
Lowell L. Getz
Keyword(s):  
Light Intensity ◽  
Dense Vegetation

Studies on the Biting Habits and Medical Importance of East African Mosquitos in the Genus Aëdes. I.—Subgenera Aëdimorphus, Banksinella and Dunnius

1960 ◽  
Vol 50 (4) ◽  
pp. 759-779 ◽  
Author(s):  
A. J. Haddow
Keyword(s):  
Rift Valley Fever Virus ◽  
Ground Level ◽  
East African ◽  
African Species ◽  
Valley Fever ◽  
Single Exception ◽  
Fourth Species ◽  
Medical Importance ◽  
Group Pattern ◽  
Biting Behaviour

The biting behaviour of East African species of Aëdes in the subgenera Aëdimorphus, Banksinella and Dunnius, as shown in numerous series of 24-hr, catches made predominantly in Uganda, is discussed. It is shown that with the single exception of A. (A.) natronius Edw., which is arboreal, all the species encountered have been most prevalent at ground level. They bite mostly by day, but A. cumminsi (Theo.) shows a marked peak of activity from just before to just after sunset, and A. natronius is crepuscular. When, however, samples were obtained in environments less favoured than the forest floor, and in which the mosquito concerned was less abundant, the biting cycle might be altered. Thus various species which were essentially diurnal at ground level in forest might be nocturnal in the canopy or in banana plantations.In some cases there seemed to be a tendency towards a group pattern of behaviour. For example, in the abnormalis (Theo.) and tarsalis (Newst.) groups of Edwards it was found that at least three species showed very similar biting cycles. A fourth species, A. nigricephalus (Theo.), which occurs in Nigeria, is reported there to differ in its biting habits, and is also strikingly different in appearance and in the structure of the terminalia.Members of all three subgenera have been involved in various isolations of virus, but it is not possible to prove that they, rather than other species of Aëdes included in the infected lots, were the vector mosquitos, except in the case of the A. tarsalis group, from which there have been two definite isolations of Rift Valley fever virus, and in that of A. circumluteolus (Theo.), which has been shown by recent work in South and East Africa to be of major importance, well over 20 isolations of virus having been made from this species. So far as is known at present, seven separate viruses and one distinct variant have been isolated from A. circumluteolus, and other members of the subgenus Banksinella also appear to be involved in transmission.

Light intensity and the oestrous cycle in albino and normally pigmented mice

1993 ◽  
Vol 27 (4) ◽  
pp. 385-390 ◽  
Author(s):  
Harry Donnelly ◽  
Palle Saibaba
Keyword(s):  
Light Intensity ◽  
Laboratory Animal ◽  
Oestrous Cycle ◽  
Lower Intensity ◽  
Albino Mice ◽  
The Difference

The effects of light intensity (15-20 lux & 220-290 lux) on the oestrous cycle of albino and normally pigmented mice were examined. The oestrous cycle of both types of mice was shorter at the lower intensity but the difference was significant only with the black mice. The proportion of albino mice from which embryos were recovered was significantly smaller than the proportion of black mice at 15-20 lux but not at 220-290 lux. No significant differences due to strain or light intensity were found in the number of embryos recovered. We conclude that pigmented mice respond in the same way as albino mice to changes in light intensity within the range normally found in laboratory animal accommodation. That is, increased light intensity prolongs the oestrous cycle and the period of vaginal cornification.

scholarly journals Autecology of Begonia in Several Locations of Flores Island

2021 ◽  
Vol 15 (1) ◽  
pp. 4-12
Author(s):  
Sutomo Sutomo ◽  
Rajif Iryadi
Keyword(s):  
Multivariate Analysis ◽  
Soil Moisture ◽  
Light Intensity ◽  
Forest Floor ◽  
National Park ◽  
Natural Habitat ◽  
Air Humidity ◽  
Factor B ◽  
Slope Factor ◽  
Minimum Interval

Human activities in forest areas such as over-harvesting of Begonia species without being balanced with their cultivation activities can threaten the existence of Begonia in nature. Autecological studies of species in their natural habitat are the initial activities for the conservation of plant species. The purpose of this study was to study the distribution of Begonia on Flores and environmental/ microclimate characteristics in several locations on Flores Island. The 10x10 m plots were placed with purposive sampling with a minimum interval of 50 m. Multivariate analysis using Canonical Corespondence Analysis (CCA) was employed to determine the effect of microclimatic factors on the composition of vegetation. Begonia kelimutensis is endemic in Kelimutu National Park, Flores lives at an altitude of 1,527 asl, at soil pH 5,8 and soil moisture of 75%, with a slope of 10 ° on the forest floor and light intensity 4,640 klux. In addition, five types of Begonia that we estimate have not been identified and two of them are identified as Begonia sumbawaensis Girm. and Begonia brangbosangensis Girm. Begonia kelimutuensis is distributed at a higher altitude than Begonia brangbosangensis. B. sumbawaensis is influenced by the slope factor while B. longifolia tends to be related to the air humidity factor. B. kelimutuensis is also often found living with Macaranga sp., and Litsea sp. B. brangbosangensis, also found near Homalanthus sp. and Calliandra callothyrsus.

Studies on the biting habits and medical importance of East African mosquitos in the genus Aëdes. II.—Subgenera Mucidus, Diceromyia, Finlaya and Stegomyia

1961 ◽  
Vol 52 (2) ◽  
pp. 317-351 ◽  
Author(s):  
A. J. Haddow
Keyword(s):  
Forest Canopy ◽  
Ground Level ◽  
Maximum Intensity ◽  
East African ◽  
Productive Area ◽  
Medical Importance ◽  
Different Levels ◽  
Diurnal Species ◽  
Biting Behaviour ◽  
Made In

The cyclic biting activities of East African mosquitos of the genus Aëdes, belonging to the subgenera Mucidus, Diceromyia, Finlaya and Stegomyia are discussed. The total number of 24-hour catches involved was 448, all in East Africa, of which 401 were made in forest in Uganda.It is pointed out that many species in the subgenera of Aëdes dealt with show arboreal tendencies of varying degree and, while a species may show a preference for some particular level, many of them appear to make daily vertical migrations. Consequently, biting may reach its maximum intensity at different times at different levels. It is also pointed out that the habits of a species may vary from one area to another, and therefore it is often best to discuss a representative series of catches from a productive area, noting such differences as may have been observed elsewhere. It has been found further that, under certain circumstances, a species may fail to show a clear pattern of biting behaviour and the possible reasons for this are discussed.All members of the subgenus Mucidus so far adequately studied are arboreal and nocturnal. In the subgenus Finlaya, A. ingrami Edw. is a mosquito of the forest understorey which bites most freely in the hour before sunset. It makes vertical migrations, however, and the biting cycle at ground-level differs from that in the trees. A. longipalpis (Grünb.) is a diurnal species of the forest canopy. A view formerly put forward by the writer, that the form of the biting cycle in this species could be attributed to different physiological groups biting at different times, can no longer be supported.In the subgenus Stegomyia, A. dendrophilus Edw. and A. apicoargenteus (Theo.) are diurnal species with rather irregular biting cycles, A. dendrophilus

scholarly journals Light intensity measurement and the biting behaviour of some sylvatic moqsuitoes of the Amazon basin (Diptera: Culicidae)

1982 ◽  
Vol 12 (1) ◽  
pp. 61-64 ◽  
Author(s):  
J. Derek Charlwood ◽  
◽  
José Lopes ◽  
Peter C. Whalley ◽  
◽  
...  
Keyword(s):  
Light Intensity ◽  
Amazon Basin ◽  
Intensity Measurement ◽  
Low Light ◽  
Light Levels ◽  
Biting Behaviour

Abstract The design of a lightmeter suitable for use at low light levels is described. Catches of mosquitoes biting man at sunset near Manaus Amazonas indicated that light intensity controls biting activity in crepuscular species to a very fine degree.

Fine structure of the retina of the giant scallop, Placopecten magellanicus

1984 ◽  
Vol 42 ◽  
pp. 312-313
Author(s):  
C.V.L. Powell
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Light Intensity ◽  
Scanning Electron Microscope ◽  
Eye Development ◽  
Preliminary Observation ◽  
Columnar Epithelium ◽  
Placopecten Magellanicus ◽  
Environmental Light ◽  
Scanning Electron

The overall fine structure of the eye in Placopecten is similar to that of other scallops. The optic tentacle consists of an outer columnar epithelium which is modified into a pigmented iris and a cornea (Fig. 1). This capsule encloses the cellular lens, retina, reflecting argentea and the pigmented tapetum. The retina is divided into two parts (Fig. 2). The distal retina functions in the detection of movement and the proximal retina monitors environmental light intensity. The purpose of the present study is to describe the ultrastructure of the retina as a preliminary observation on eye development. This is also the first known presentation of scanning electron microscope studies of the eye of the scallop.

Effect of light intensity on the ultrastructure of the filamentous cyanobacterium, Anabaena variabilis

1988 ◽  
Vol 46 ◽  
pp. 300-301
Author(s):  
C. S. Bricker ◽  
S. R. Barnum ◽  
B. Huang ◽  
J. G. Jaworskl
Keyword(s):  
Fatty Acid ◽  
Light Intensity ◽  
Acid Content ◽  
Fatty Acid Content ◽  
Anabaena Variabilis ◽  
Chloroplast Envelope ◽  
Major Constituent ◽  
Filamentous Cyanobacterium ◽  
Photosynthetic Membrane ◽  
Effect Of Light

Cyanobacteria are Gram negative prokaryotes that are capable of oxygenic photosynthesis. Although there are many similarities between eukaryotes and cyanobacteria in electron transfer and phosphorylation during photosynthesis, there are two features of the photosynthetic apparatus in cyanobacteria which distinguishes them from plants. Cyanobacteria contain phycobiliproteins organized in phycobilisomes on the surface of photosynthetic membrane. Another difference is in the organization of the photosynthetic membranes. Instead of stacked thylakolds within a chloroplast envelope membrane, as seen In eukaryotes, IntracytopIasmlc membranes generally are arranged in three to six concentric layers. Environmental factors such as temperature, nutrition and light fluency can significantly affect the physiology and morphology of cells. The effect of light Intensity shifts on the ultrastructure of Internal membrane in Anabaena variabilis grown under controlled environmental conditions was examined. Since a major constituent of cyanobacterial thylakolds are lipids, the fatty acid content also was measured and correlated with uItrastructural changes. The regulation of fatty acid synthesis in cyanobacteria ultimately can be studied if the fatty acid content can be manipulated.

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.

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