Visual Attraction as a Principle in Design of Mosquito Traps

1964 ◽  
Vol 96 (1-2) ◽  
pp. 118-118 ◽  
Author(s):  
W. O. Haufe
Keyword(s):  
Light Conditions ◽  
Ecological Studies ◽  
Light Traps ◽  
Black And White ◽  
Large Numbers ◽  
Air Space ◽  
Ordinary Light ◽  
Visual Attraction ◽  
Pattern Comparison ◽  
Night And Day

A principle of visual attraction has been used in the design of mosquito traps for ecological studies. Tests in the field have shown that the design is efficient in capturing large numbers of mosquitoes in locations where ordinary light traps were unsatisfactory. Positive 24-hour attraction is achieved under naturally varying light conditions by using a black and white pattern that is superior in contrast to competing patterns in the environment. The sampling unit, in terms of air space, depends on the distance between contours in the pattern. Comparison with a suction trap under identical conditions show no significant differences in the ratio of empirically divided day to night catches. In very dark environments, a relatively uniform contrast in the pattern may be maintained between night and day with white light confined to the cylinder by collimators. Illumination in the yellow-red end of the spectrum reduces attraction to the pattern.

scholarly journals Culicoides biting midges at the National Zoological Gardens of South Africa : research communication

2007 ◽  
Vol 74 (4) ◽  
Author(s):  
K. Labuschagne ◽  
L.J. Gerber ◽  
I. Espie ◽  
S. Carpenter
Keyword(s):  
South Africa ◽  
Vector Competence ◽  
Far East ◽  
Wild Animals ◽  
Light Traps ◽  
Biting Midges ◽  
Research Communication ◽  
Culicoides Imicola ◽  
Large Numbers ◽  
Culicoides Biting Midges

Culicoides biting midges (Diptera: Ceratopogonidae) are responsible for the transmission of a large number of pathogens to livestock and wild animals. In this study the presence of the genus, using light traps based at four different sites within the National Zoological Gardens of South Africa, was investigated during 2002-2004. In total, 37 species were recorded, including large numbers of Culicoides imicola Kieffer, 1913, which is responsible for the transmission of economically important arboviruses in South Africa, Europe, Middle and Far East. These results are discussed with reference to the wider Culicoides fauna in the Onderstepoort area of South Africa, their vector competence as well as biosecurity at the National Zoological Gardens.

‘Same Race’ Adoption Policy: Anti-racism or Racism?

1995 ◽  
Vol 24 (4) ◽  
pp. 473-491 ◽  
Author(s):  
Marie Macey
Keyword(s):  
Social Relationships ◽  
Social Relations ◽  
Transracial Adoption ◽  
Older Children ◽  
Binary Opposition ◽  
White People ◽  
Policy And Practice ◽  
Black And White ◽  
Large Numbers ◽  
The Usa

ABSTRACTThis article analyses the theoretical and empirical underpinnings of ‘same race’ (‘black on black’) adoption policy in Britain and the accompanying antagonism to transracial adoption. In order to highlight the assumptions on which current policy and practice are based, it refers to infant adoption, not to the placement of older children who have already experienced family life in particular class and ethnic locations. The author suggests that current policies, amounting to a virtual ban on transracial adoption in both Britain and the USA, are based on a binary opposition between black and white which denies differences within these categories and similarities across them. She also suggests that this portrayal of black and white people in monolithic terms rests on racist stereotyping and is a distortion of the reality of social relations in contemporary society which marginalises large numbers of people whose origins include both black and white. It draws attention away from crucial questions on adoption in heterogeneous, hierarchical, racially ordered societies and has implications for social relationships in such societies.

scholarly journals Induced changes in the pigmentation of the pupœ of the butterfly P ieris napi L., and their inheritance

1928 ◽  
Vol 102 (718) ◽  
pp. 347-353 ◽  
Keyword(s):  
Light Conditions ◽  
Green Colour ◽  
Ordinary Light ◽  
Bright Green ◽  
Induced Changes

It has, of course, long been known that the pigmentation of the pupae of the two lepidopterous species, Pieris brassicœ L. and P. rapœ L. (Poulton, 1887), is influenced by the colour of the light to which the larvae from which they are developed are exposed just before pupation. In particular, if the larvae are allowed to pupate in orange light, a heavy percentage of the pupae obtained is of a bright green colour. This coloration, however, simply depends upon the fact that the formation of the various pigments, white and black, in the chitin of the pupal integument is more or less inhibited by orange light. As a consequence, the colour perceived in pupæ so affected is that of the hæmolymph within, and hence the chrysalids appear green. Recently, in addition to confirming these earlier observations, Dürken (1923) and Brecher (1923) have bred from butterflies reared from the treated larvæ and pupæ. The larvæ descended from the orange glass cultures, even when pupating under ordinary light conditions, gave rise to a set of pupæ including many more green individuals than the control lots. Clearly, therefore, the acquired pupal green had been inherited. In view of current biological controversies, such an effect was of primary importance. Repetition and confirmation of the work were highly desirable, and the present work was therefore undertaken.

A Method For Marking Small Juvenile Gastropods

1993 ◽  
Vol 73 (4) ◽  
pp. 963-966 ◽  
Author(s):  
Louis A. Gosselin
Keyword(s):  
Foraging Behaviour ◽  
Accurate Determination ◽  
Ecological Studies ◽  
Simple Method ◽  
Marine Gastropods ◽  
Small Juvenile ◽  
External Shell ◽  
Large Numbers ◽  
Invertebrate Larvae

Methods used to identify individual organisms consistently over time have been invaluable tools in ecological studies, enabling reliable assessments of time-dependent parameters such as growth and mortality, and an accurate determination of their variance. These methods have proved to be particularly amenable to gastropods owing to the presence of an external shell on which marks or tags can be applied with little or no adverse effects on the animal. Marking and tagging techniques have enabled the study of several ecological parameters in adult marine gastropods, including growth (Frank, 1965; Hughes, 1972; Palmer, 1983; Gosselin & Bourget, 1989), mortality (Frank, 1965; Hughes, 1972), movements (Frank, 1965; Chapman, 1986), and foraging behaviour (Menge, 1974; Hugheset al., 1992). Small organisms, however, can pose considerable problems for individual marking (Southwood, 1978). As a result, marking and tagging methods have seldom been applied to newly hatched or recently settled juvenile marine gastropods. Several methods have been developed for simultaneously labelling large numbers of invertebrate larvae (Levin, 1990), and some of these methods may be applicable to juvenile gastropods. The usefulness of these methods, however, is limited because all animals receive the same label and, consequently, individual animals cannot be recognized. To my knowledge, no method of individually marking very small juvenile marine gastropods has been documented. In fact, it is sometimes perceived that small juveniles cannot be individually marked due to their small size and sensitivity (Frank, 1965; Palmer, 1990). The object of this paper is to present a simple method of marking early juvenile gastropods, which consists of applying colour codes to the shells of individuals as small as 0·9 mm in length.

scholarly journals All day-long: Sticklebacks effectively forage on whitefish eggs during all light conditions

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255497
Author(s):  
Jan Baer ◽  
Sarah Maria Gugele ◽  
Joachim Bretzel ◽  
J. Tyrell DeWeber ◽  
Alexander Brinker
Keyword(s):  
Egg Production ◽  
Gasterosteus Aculeatus ◽  
Energy Content ◽  
Stomach Content Analysis ◽  
Pelagic Zone ◽  
Light Conditions ◽  
Egg Predation ◽  
Large Numbers ◽  
Potential Benefits ◽  
Freshwater Stickleback

The three-spined stickleback Gasterosteus aculeatus invaded Lake Contance in the 1940s and expanded in large numbers from an exclusively shoreline habitat into the pelagic zone in 2012. Stickleback abundance is very high in the pelagic zone in winter near the spawning time of pelagic whitefish Coregonus wartmanni, and it is hypothesized that this is triggered by the opportunity to consume whitefish eggs. Field sampling has qualitatively confirmed predation of whitefish eggs by stickleback, but quantification has proven difficult due to stormy conditions that limit sampling. One fundamental unknown is if freshwater stickleback, known as visual feeders, can successfully find and eat whitefish eggs during twilight and night when whitefish spawn. It is also unknown how long eggs can be identified in stomachs following ingestion, which could limit efforts to quantify egg predation through stomach content analysis. To answer these questions, 144 individuals were given the opportunity to feed on whitefish roe under daylight, twilight, and darkness in controlled conditions. The results showed that stickleback can ingest as many as 100 whitefish eggs under any light conditions, and some individuals even consumed maximum numbers in complete darkness. Furthermore, eggs could be unambiguously identified in the stomach 24 hours after consumption. Whitefish eggs have 28% more energy content than the main diet of sticklebacks (zooplankton) based on bomb-calorimetric measurements, underlining the potential benefits of consuming eggs. Based on experimental results and estimates of stickleback abundance and total egg production, stickleback could potentially consume substantial proportions of the total eggs produced even if relatively few sticklebacks consume eggs. Given the evidence that stickleback can feed on eggs during nighttime spawning and may thereby hamper recruitment, future studies aimed at quantifying actual egg predation and resulting effects on the whitefish population are urgently needed.

scholarly journals Enhanced Seed Germination and Seedling Growth of Tillandsia Eizii In Vitro

HortScience ◽  
2003 ◽  
Vol 38 (1) ◽  
pp. 101-104 ◽  
Author(s):  
Kimberly A. Pickens ◽  
James M. Affolter ◽  
Hazel Y. Wetzstein ◽  
Jan H.D. Wolf
Keyword(s):  
Seed Germination ◽  
In Vitro Culture ◽  
Seedling Growth ◽  
Culture Medium ◽  
Habitat Destruction ◽  
Light Conditions ◽  
Physiological Constraints ◽  
Large Numbers ◽  
In The Wild

Tillandsia eizii is an epiphytic bromeliad that due to over-collection, habitat destruction, and physiological constraints has declined to near threatened status. This species exhibits high mortality in the wild, and seed are characterized by low percentages of germination. As a means to conserve this species, in vitro culture protocols were developed to enhance seed germination and seedling growth. A sterilization protocol using 70% ethanol for 2 minutes followed by 2.6% NaOCl for 40 minutes disinfested seed and promoted seedling growth. Sucrose incorporated into the culture medium had no effect on germination or growth, while NAA inhibited growth, but not germination. Cultures maintained under a 16-hour photoperiod at 22 °C exhibited greater growth than those grown at 30 °C. Seed that germinated in the dark remained etiolated and failed to develop even after transfer to light conditions. Plants grown in vitro were successfully acclimatized and transferred to the greenhouse. Over 86% survival and rapid growth were obtained with either an all-pine-bark medium, or a mixture of 2 redwood bark: 2 fir bark: 2 potting mix: 1 perlite. This demonstrated that in vitro culture of seed may be used to rapidly produce large numbers of T. eizii, and thus can be used for the conservation and reintroduction of this species.

scholarly journals Calculation of contrast for computer simulated resolution chart image

2021 ◽  
Vol 2127 (1) ◽  
pp. 012021
Author(s):  
Yu Yu Kachurin ◽  
A V Kryukov ◽  
O A Kananykhin ◽  
A V Fedorinov
Keyword(s):  
Transfer Function ◽  
Modulation Transfer Function ◽  
Monochromatic Light ◽  
Objective Lens ◽  
Image Simulation ◽  
Light Conditions ◽  
Modulation Transfer ◽  
Black And White ◽  
Spatial Frequencies ◽  
Diffraction Modulation

Abstract The work is devoted to the analysis of the resolution chart image created with the Image Simulation mode of ZEMAX software. The changes in image quality are simulated using the model of Helios-44M-4 photographic objective lens. The research is conducted for monochromatic light conditions and computer simulated resolution test chart as an object for the lens with different chart positions. An axial beam and an off-axis beam that corresponds to the maximum object space field angle are analyzed. The calculation of contrast of the simulated resolution chart images is made modeling different spatial frequencies of the chart lines. The contrast is calculated in three ways. The first way uses the maximum and minimum values of the image illumination, and the second and third ways are based on the integral values of the illumination of black and white lines, calculated with the method of rectangles and the method of trapeziums, respectively. Having been calculated the values of contrast are compared with the theoretical values of the diffraction modulation transfer function obtained with ZEMAX.

scholarly journals Movement behaviour and video tracking of Milnesium tardigradum Doyère, 1840 (Eutardigrada, Apochela)

2010 ◽  
Vol 79 (1) ◽  
pp. 33-38 ◽  
Author(s):  
Denis Shcherbakov ◽  
Ralph O. Schill ◽  
Franz Brümmer ◽  
Martin Blum
Keyword(s):  
Video Tracking ◽  
Sexual Partners ◽  
Gaseous Exchange ◽  
Light Conditions ◽  
Movement Behaviour ◽  
Custom Made ◽  
The Mean ◽  
Night And Day ◽  
High Degree ◽  
Water Bears

Tardigrades or ‘water-bears’ live in moist environments with a high degree of gaseous exchange. In tardigrades, locomotion is essential, e.g. for feeding, to find sexual partners and to adjust the level of hydration by moving to wetter or dryer environments. Here we report on the movement behaviour of Milnesium tardigradum in automated experiments using custom-made video tracking software. The experiments involved 754 hours of recording involving 32 individuals. No significant differences in mobility were observed under infrared versus visible light conditions, representing night and day, respectively. The mean recorded velocity was 23.3 ± 7.38 mm/h, with a maximum of 1166.4 mm/h.

An overview of the Syrphidae (Diptera) of Saudi Arabia

Zootaxa ◽  
2020 ◽  
Vol 4855 (1) ◽  
pp. 1-69
Author(s):  
HASSAN A. DAWAH ◽  
MOHAMMED A. ABDULLAH ◽  
SYED KAMRAN AHMAD ◽  
HATHAL AL-DHAFER ◽  
JAMES TURNER
Keyword(s):  
Saudi Arabia ◽  
World Wide ◽  
Wide Distribution ◽  
Biological Data ◽  
Species Level ◽  
Site Quality ◽  
Ecological Studies ◽  
Light Traps ◽  
Plant Pests ◽  
Malaise Traps

Despite the species richness of hoverflies (Diptera: Syrphidae) world-wide (about 6,200 species) and their role as agents for controlling plant pests, their significance as pollinators, and as bioindicators of site quality, hoverfly fauna of Saudi Arabia is poorly known. In exploring the biodiversity of Diptera in southwest Saudi Arabia a survey of the hoverfly fauna of Jazan, Asir, Najran and Al-Baha was performed mainly using Malaise traps, sweep nets and light traps from 2011 to 2014. Forty known species of Syrphidae were identified and recorded in this study, 19 of them new to Saudi Arabia. This makes the total number of Syrphidae species recorded in Saudi Arabia (including one species recorded by others) is 41. In addition, three taxa belonging to the genera Eumerus Meigen, Orthonevra Macquart, and Paragus Latreille that could not be identified safely to species level because there were no adequate identification keys or males were missing in the collected material. A key to the genera of Syrphidae occurring in Saudi Arabia is provided. The fauna of Syrphidae recorded in this study consists much more of Afrotropical zoogeographical elements than Palaearctic ones. A complete checklist of Syrphidae of Saudi Arabia is provided. Biological data, where known, and world-wide distribution of the studied taxa are provided. This paper is published with the purpose of assisting biogeographical, biological or ecological studies on syrphids in Saudi Arabia. 

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