Light-trap and suction-trap catches of insects in the northern Gezira, Sudan, in the season of southward movement of the Inter-Tropical Front

1973 ◽  
Vol 62 (4) ◽  
pp. 571-596 ◽  
Author(s):  
John Bowden ◽  
David G. Gibbs
Keyword(s):  
Full Moon ◽  
Light Trap ◽  
Lunar Cycle ◽  
Light Traps ◽  
Trap Site ◽  
Long Distance ◽  
Suction Trap ◽  
Displacement System ◽  
Source Populations ◽  
Trap Catches

Catches in light-traps adjoining cotton were obtained at the time of seasonal southward movement of the Inter-Tropical Front (ITF) in October, and during most of the following two months. Taxa studied were mostly Orthoptera and moths, many associated with sorghum, others long-distance migrants. Suction-trap catches at three heights up to 50 ft were obtained for short periods in October and November, and aircraft catches at 250 ft were also available on two days. Suction-trap catches of grass-feeding Homoptera suggest that displacement of these insects was associated with changes in wind direction marking movement of the ITF in October. The exact form of the displacement system in relation to the front cannot be reconstructed from catches at a single place, but it seems likely that proximity of the front at or soon after the time of a brief period of crepuscular activity stimulates insects to take flight and rise to 50 ft or more so that they are displaced. In many taxa, light-trap catches showed a regular pattern of increase, with only slight nightly fluctuations from a logarithmic trend, following full moon. Other increases were superimposed on this pattern at times when the ITF passed north of the trap site, and in some taxa particularly when it was far north. The pattern of change after full moon, shown most clearly in taxa with source populations close to the trap, was related to the moon's influence on the range of trap effectiveness. But various qualitative variations suggest that, in addition, aspects of behaviour or development may have adaptive relationships to the lunar cycle; variations include differences between taxa, particularly in timing of catch changes, and increasing proportion and decreasing maturity of females of certain taxa at the time of the regular increases in catch.

The influence of moonlight on catches of insects in light-traps in Africa. III. The effective radius of a mercury-vapour light-trap and the analysis of catches using effective radius

1975 ◽  
Vol 65 (2) ◽  
pp. 303-348 ◽  
Author(s):  
John Bowden ◽  
Marjory G. Morris
Keyword(s):  
Full Moon ◽  
Light Trap ◽  
Effective Radius ◽  
Mercury Vapour ◽  
Light Traps ◽  
Primary Determinant ◽  
New Moon ◽  
Insect Activity ◽  
The Times ◽  
Trap Catches

AbstractUsing the inverse square law, estimates can be made of the distances at which illumination from a light-trap is equal to that from background sources. From these distances an index of trap radius can be constructed which can be considered as a measure of trap potential. Between new moon and full moon trap radii vary, depending upon the times of the night at which the trap may be operating, in ratios from about 10:1 to 15:1. A comparable index of light-trap catches can be calculated which allows catches to be examined in relation to changing radius of the trap. Analysis of a series of catches in Uganda and Ghana shows that many species are more abundant than expected in periods of moonlight, particularly at and near full moon, the biggest difference between new moon and full moon being about 10:1 for Marasmia trapezalis (Gn.), whereas the Isoptera, Bostrychidae and Spodoptera triturata (Wlk.) are 3–4 times more frequent at full moon. The ratios between catch at new moon and catch at full moon suggest that the primary determinant of catch is the frequency with which insects cross the boundary of a region of influence whose size is determined by a radius of equal energy. Deductions about the pattern of insect activity through a lunation, and nightly, and the general agreement between curves describing the change in radius of the trap and those of trap catches suggest that changes in catch over a lunation can be explained by changes in the effectiveness of the trap. When corrections are made to allow for such changes, all taxa show some increase in numbers in moonlit periods and in many taxa this increase is substantial. Correction of catches should take account of flight periodicity and this periodicity should, if possible, be confirmed by methods independent of light-traps.

Effects of lunar phase on light trap catches of the Malayan black rice bug, Scotinophara coarctata (Heteroptera: Pentatomidae)

1993 ◽  
Vol 83 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Kiyomitsu Ito ◽  
Hachiro Sugiyama ◽  
Nik Mohd. Noor b. Nik Salleh ◽  
Chang Poon Min
Keyword(s):  
Full Moon ◽  
Light Trap ◽  
Physiological Status ◽  
Growth Stages ◽  
Lunar Phase ◽  
Starvation Period ◽  
Rice Bug ◽  
New Moon ◽  
Fat Bodies ◽  
Trap Catches

AbstractDaily light trap catches of Scotinophara coarctata (Thunberg) were analysed from mid-September 1986 to December 1990 and the physiological status of the trapped adults was examined. The catch size fluctuated synchronously with the lunar phase; large catches occurred around the full moon period and very few adults were trapped around the new moon period. Seasonally, the catches were large from January to March and from July to September, while they were small from May to June and October to November. The seasonal fluctuations of the catches seemed to be related to the growth stages of the rice plants on which the adults multiplied. The sex ratio of trapped adults was biased toward males, unlike that of the cage-reared insects which was 1:1. Most of the trapped females showed undeveloped ovaries and some of these females appeared to have oviposited previously. Light-attracted adults showed a considerable tolerance to starvation and survived for 20–30 days when they were given water, but for only two days in the absence of water. When the light-attracted females were supplied with food, their ovaries developed rapidly and females with mature eggs were produced after nine days. When the starvation period was prolonged, the ovaries remained immature and the fat bodies reduced in size. The nocturnal take-off of the adults was not triggered simply by the full moon illumination. Adult eclosion did not synchronize with the moon cycle.

Moonlight and the biting activity of Culex (Melanoconion) portesi Senevet & Abonnenc and C. (M.) taeniopus D. & K. (Diptera, Culicidae) in Trinidad forests

1975 ◽  
Vol 65 (1) ◽  
pp. 81-96 ◽  
Author(s):  
John B. Davies
Keyword(s):  
Full Moon ◽  
Light Trap ◽  
Ground Level ◽  
The Moon ◽  
Light Traps ◽  
Baited Traps ◽  
Suction Traps ◽  
New Moon ◽  
Phases Of The Moon ◽  
Increased Activity

AbstractThe biting activity of Culex (Melanoconion) portesi Senevet & Abonnenc and C. (M.) taeniopus D. & K. in a secondary seasonal marsh forest in Trinidad was studied by means of catches by six mouse-baited suction traps, and a single light-trap. The traps were cleared at hourly intervals between 17.00 h and 07.00 h on nights which approximated to the new, first quarter, full and last quarter phases of the moon. The catches were compared with illumination at canopy and ground level which was estimated by selenium photocells whose output was recorded on the continuous chart of a servo-potentiometer. Humidity, rainfall, temperature and cloud cover were also recorded. In the suction traps both species showed peaks of activity at evening and dawn twilight at new moon, although the dawn peak was not very pronounced with C. taeniopus, but this pattern was modified on other nights in a manner which was consistent with moon age. At full moon the evening and dawn peaks were replaced by increased activity during moonrise and the middle of the night. The light-traps failed to show the evening and dawn activity and did not always duplicate the baited traps during darkness. Two hypotheses based on either a permissive range of illumination or an underlying circadian rhythm are discussed; neither fully explains the observed biting activity. Although an association between moonlight and biting activity does exist, an understanding of its nature will require more experimental data.

The range of visual attraction and the effect of competitive visual attractants upon mosquito (Diptera: Culicidae) flight

1980 ◽  
Vol 70 (2) ◽  
pp. 321-342 ◽  
Author(s):  
W. L. Bidlingmayer ◽  
D. G. Hem
Keyword(s):  
Long Distance ◽  
Flight Behaviour ◽  
Culiseta Melanura ◽  
Culex Nigripalpus ◽  
Psorophora Columbiae ◽  
Suction Traps ◽  
Wind Velocities ◽  
Visual Attraction ◽  
Suction Trap ◽  
Trap Catches

AbstractNocturnally active mosquitoes are attracted visually to large (1·5 × 2·4 m) unpainted plywood suction traps. Such traps, which discharge air horizontally in one direction only, were placed in an open field in Florida in various patterns to study the flight behaviour of mosquitoes. When four traps were placed 15 m apart in a column, the two end traps captured 83 or 53% more mosquitoes than the two inner traps, depending upon whether the air discharged from the traps was perpendicular to, or in line with, the trap column. When the traps were spaced 30 m apart, the end traps captured only 13% more than the inner traps, indicating that at this distance visual competition between traps was small. When 16 suction traps were spaced 15 m apart in a grid of four columns of four traps each, the traps at the four corners of the grid captured about 2·1 times, and traps between the corner traps along the edge of the grid 1·5 times, as many mosquitoes of most species as traps within the grid. Subsequently, four additional traps were placed 15 m beyond the corner traps, and these traps captured 3·3 times as many mosquitoes as traps inside the grid. Traps within the grid had four adjacent traps while traps at the edge, corner, and beyond the corner had three, two and one adjacent traps, respectively. The numbers captured by a trap at a particular location in the grid were inversely related to the number of adjacent traps, viz., suction-trap catches were decreased by about 33% as the number of adjacent traps were increased and thus each trap acted as a competing visual attractant on nearby traps. It was estimated that an isolated suction trap would capture approximately five times as many mosquitoes as a trap inside the grid. Assuming these differences between trap collections were caused by the distance at which mosquitoes respond to the traps and thus would be proportional to the visually unobstructed area about each trap, it was calculated that most adults responded visually to the traps from distances of approximately 15·5 to 19 m. Aedes vexans (Mg.) and Psorophora columbiae (D. & K.) were most responsive, followed by Culex nigripalpus Theo. and Culiseta melanura (Coq.) and then by Anopheles crucians Wied., P. ciliata (F.) and Uranotaenia lowii Theo. Only U. sapphirina (O.S.) and Culex quinquefasciatus Say appeared to possess visual ranges of 7.5 m or less. Visually conspicuous objects can serve as long-distance attractants. Low air velocities caused appreciable reductions in trap collections. At a distance of 15 m, the velocity of air discharged from the traps was only 0·6 m/s, but catches from a trap downstream of an adjacent trap were reduced by 17%. Catches from rows of traps downstream from one, two or three rows of traps were reduced by 15, 36, and 51%, respectively. Estimates of mosquito population densities in a natural environment will be affected by the differing visual attractiveness of objects of irregular distribution and sizes and their effect upon wind velocities.

The influence of moonlight on catches of insects in light-traps in Africa. Part I. The moon and moonlight

1973 ◽  
Vol 63 (1) ◽  
pp. 113-128 ◽  
Author(s):  
John Bowden
Keyword(s):  
Light Trap ◽  
Lunar Cycle ◽  
Moon Phase ◽  
The Moon ◽  
Light Traps ◽  
Trap Catch

AbstractAn account is presented of the distribution and amounts of moonlight in latitudes near the equator. This includes a Table on the amount of moonlight for each hour of the night throughout a standard lunar cycle, applicable to any locality between 10°N and 10°S, and a Table of standard groups of moon phase which can be used at any locality irrespective of latitude. The construction of these Tables is described in detail and their use briefly discussed. A method is described which enables light-trap catch records to be arranged for analysis directly against moon phase.

Relationship to human biting collections and influence of light and bednet in CDC light-trap catches of West African malaria vectors

1998 ◽  
Vol 88 (5) ◽  
pp. 503-511 ◽  
Author(s):  
C. Costantini ◽  
N.F. Sagnon ◽  
E. Sanogo ◽  
L. Merzagora ◽  
M. Coluzzi
Keyword(s):  
Light Trap ◽  
West African ◽  
Malaria Vectors ◽  
Prototype Model ◽  
Light Traps ◽  
Mosquito Net ◽  
Cdc Light Trap ◽  
Incandescent Bulb ◽  
Human Landing ◽  
Trap Catches

AbstractThe efficiency of miniature CDC light-traps in catching West African malaria vectors was evaluated during two rainy seasons in a village near Ouagadougou, Burkina Faso. Traps were employed both indoors and outdoors using human baits protected by an insecticide-free mosquito-net and different sources of light. Indoors, light from incandescent bulbs increased the catch of Anopheles gambiae s.l. (mainly A. arabiensis Patton and the Mopti chromosomal form of A. gambiae s.s. Giles) and A. funestus Giles c. 2.5 times as compared to traps whose light bulb was removed. Conversely, the difference was not significant when a UV ‘Blacklight-blue’ fluorescent tube was compared to the incandescent bulb. Protecting the bait with a mosquito-net increased the catch c. 3 times for A. gambiae s.l. and c. 3.5 times for A. funestus. A prototype model of double bednet gave intermediate yields. Outdoors, the addition of incandescent bulbs to unlighted traps did not significantly increase the number of vectors caught, but the addition of the mosquito-net to the unprotected human bait did so by c. 1.5–4 times. Thus, the CDC light-trap hung close to a human sleeping under a bednet and fitted with an incandescent bulb, was considered the most practical and efficient in terms of numbers of vectors caught, consequently its indoor efficiency was compared to human landing catches on single collectors and estimated to be 1.08 times and density-independent. Outdoor light-trap catches were either not significantly correlated to biting collections (as for A. gambiae s.l.), or density-dependent in their efficiency (as for A. funestus); thus, they were not considered a reliable means for estimating malaria vector outdoor biting densities in this area. No difference was found in the parous rate of A. gambiae s.l. samples obtained with CDC light-traps and human landing collections.

scholarly journals Abundance of early life stages of the surf silverside Notocheirus hubbsi (Teleostei, Atheriniformes) in the coastal nearshore of central Chile

2021 ◽  
Vol 56 (1) ◽  
pp. 74
Author(s):  
Francisca Zavala-Muñoz ◽  
Mauricio F. Landaeta ◽  
Valentina Bernal-Durán ◽  
Claudia A. Bustos ◽  
Bryan S. Dyer
Keyword(s):  
Full Moon ◽  
Light Trap ◽  
Lunar Cycle ◽  
Early Life Stages ◽  
Entire Study Period ◽  
Austral Spring ◽  
Entire Study ◽  
Central Chile ◽  
New Moon ◽  
Set Up

The abundance of early stages of the surf silverside Notocheirus hubbsi in nearshore waters of central Chile, collected in samplings set up to assess the lunar cycle during austral spring and summer is reported. A total of 19 specimens were collected with light traps, 16 larvae (7.89-16.20 mm SL) in austral spring and 3 juveniles (30.70-34.60 mm SL) in summer. Capture per unit effort (CPUE) varied from 0.33 to 2.00 ind. light trap-1 night-1 during the entire study period (September 2015-February 2016, and September 2016-February 2017). N. hubbsi catches recorded maximum abundance during the new moon and no catches during full moon.

The influence of moonlight on catches of insects in light-traps in Africa. Part II. The effect of moon phase on light-trap catches

1973 ◽  
Vol 63 (1) ◽  
pp. 129-142 ◽  
Author(s):  
J. Bowden ◽  
B. M. Church
Keyword(s):  
Light Trap ◽  
Lunar Cycle ◽  
Early Morning ◽  
Insect Behaviour ◽  
Moon Phases ◽  
Insect Activity ◽  
The Times ◽  
Phases Of The Moon ◽  
Night Illumination ◽  
Trap Catches

AbstractNightly light-trap catches of insects, covering periods of 2–5 years, from two sites in Africa within 10° of the equator are examined in relation to the regular changes in night illumination of the lunar cycle. For several species average log catches at different phases of the moon are almost linearly related to (log) night illumination, catches of some species, such as Isoptera and Bostrychidae, increasing and of others, such as Marasmia trapezalis(Gn.) (Pyralidae), Lampyridae and Dorylus spp. (Formicidae), decreasing with moonlight. Relative catches of M. trapezalis and Bostrychidae varied by a factor of 30:1 between no moon and full moon. Analysis of whole-night catches gives some evidence on the pattern of insect activity through the night, identifying Syntomis monothyris (Hmps.) (Ctenuchidae) and Stemorrhages sericea (Dru.) (Pyralidae) in particular as early morning fliers. Evidence on how night illumination affects catch, and on the times of night when illumination has most effect, is consistent for the two sites and for different years. However, any adjustment of nightly catches to those expected under standard conditions of illumination can only be approximate. Although most of the differences between catches at different moon phases are accounted for by night illumination, many factors influence catch on an individual night, and moonlight is a major factor only for certain species. A hypothesis about how a light-trap may affect insect behaviour allows changes in catch of some species over the lunar cycle to be explained by the influence of background illumination on trap effectiveness.

The relationship between light- and suction-trap catches of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae), and the adjustment of light-trap catches to allow for variation in moonlight

1981 ◽  
Vol 71 (4) ◽  
pp. 621-629 ◽  
Author(s):  
John Bowden
Keyword(s):  
Light Trap ◽  
Chrysoperla Carnea ◽  
Flight Period ◽  
Background Illumination ◽  
Trap Catch ◽  
Southern England ◽  
Suction Trap ◽  
Trap Catches ◽  
The Relationship

AbstractAnalysis of catches of Chrysoperla carnea (Steph.) in a light-trap and a suction trap at Rothamsted, southern England, showed that the light-trap catch varied as predicted from a model proposed to describe the functioning of a light-trap: catch = constant × , where W = trap illumination and I = background illumination. After adjustment to allow for changes in illumination during the flight period of C. carnea, the light-trap catch was very similar to the suction-trap catch. For C. carnea, a light-trap provides as unbiased a sample as a suction trap, but because of variation in trap effectiveness with variation in illumination, light-trap catches obscure changes in activity and abundance. Although similar studies are desirable to confirm this for other species, it is suggested that in light-trap studies catches should be adjusted to allow for changes in illumination during flight or trapping periods.

Latitudinal and seasonal changes of nocturnal illumination with a hypothesis about their effect on catches of insects in light-traps

1984 ◽  
Vol 74 (2) ◽  
pp. 279-298 ◽  
Author(s):  
John Bowden
Keyword(s):  
Seasonal Changes ◽  
Light Trap ◽  
Light Sources ◽  
Summer Solstice ◽  
Light Traps ◽  
Time And Space ◽  
Trap Catches ◽  
Trap Sample ◽  
Over Time

AbstractAn account is given of changes in nocturnal illumination at the spring and autumn equinoxes and summer and winter solstices at latitudes between 50 and 60°N. A Relative Trap Index (RTI) was devised to describe changes in light-trap effectiveness and used to adjust catches of Noctuidae and Geometridae for change in trap effectiveness caused by seasonal and latitudinal change in nocturnal illumination at latitudes between 50 and 58°N. When so adjusted, catches were frequently larger in northern than in southern latitudes, not smaller as unadjusted catches show. It is clear that unless light-trap catches are adjusted to allow for changes of illumination, comparisons over time and space, particularly those which involve assumptions about sample constancy, are suspect. Because of the large differences in RTI that may exist between northern and southern traps, particularly in summer and between the summer solstice and other times, it may be necessary to use different light sources at different times of year to maintain a consistent trap sample.

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