Insect Flight Behavior Research Articles

So near and yet so far: harmonic radar reveals reduced homing ability of Nosema infected honeybees.

Pathogens may gain a fitness advantage through manipulation of the behaviour of their hosts. Likewise, host behavioural changes can be a defence mechanism, counteracting the impact of pathogens on host fitness. We apply harmonic radar technology to characterize the impact of an emerging pathogen - Nosema ceranae (Microsporidia) - on honeybee (Apis mellifera) flight and orientation performance in the field. Honeybees are the most important commercial pollinators. Emerging diseases have been proposed to play a prominent role in colony decline, partly through sub-lethal behavioural manipulation of their hosts. We found that homing success was significantly reduced in diseased (65.8%) versus healthy foragers (92.5%). Although lost bees had significantly reduced continuous flight times and prolonged resting times, other flight characteristics and navigational abilities showed no significant difference between infected and non-infected bees. Our results suggest that infected bees express normal flight characteristics but are constrained in their homing ability, potentially compromising the colony by reducing its resource inputs, but also counteracting the intra-colony spread of infection. We provide the first high-resolution analysis of sub-lethal effects of an emerging disease on insect flight behaviour. The potential causes and the implications for both host and parasite are discussed.

Early metamorphic insertion technology for insect flight behavior monitoring.

Early Metamorphosis Insertion Technology (EMIT) is a novel methodology for integrating microfabricated neuromuscular recording and actuation platforms on insects during their metamorphic development. Here, the implants are fused within the structure and function of the neuromuscular system as a result of metamorphic tissue remaking. The implants emerge with the insect where the development of tissue around the electronics during pupal development results in a bioelectrically and biomechanically enhanced tissue interface. This relatively more reliable and stable interface would be beneficial for many researchers exploring the neural basis of the insect locomotion with alleviated traumatic effects caused during adult stage insertions. In this article, we implant our electrodes into the indirect flight muscles of Manduca sexta. Located in the dorsal-thorax, these main flight powering dorsoventral and dorsolongitudinal muscles actuate the wings and supply the mechanical power for up and down strokes. Relative contraction of these two muscle groups has been under investigation to explore how the yaw maneuver is neurophysiologically coordinated. To characterize the flight dynamics, insects are often tethered with wires and their flight is recorded with digital cameras. We also developed a novel way to tether Manduca sexta on a magnetically levitating frame where the insect is connected to a commercially available wireless neural amplifier. This set up can be used to limit the degree of freedom to yawing "only" while transmitting the related electromyography signals from dorsoventral and dorsolongitudinal muscle groups.

Early Metamorphic Insertion Technology for Insect Flight Behavior Monitoring

Early Metamorphosis Insertion Technology (EMIT) is a novel methodology for integrating microfabricated neuromuscular recording and actuation platforms on insects during their metamorphic development. Here, the implants are fused within the structure and function of the neuromuscular system as a result of metamorphic tissue remaking. The implants emerge with the insect where the development of tissue around the electronics during pupal development results in a bioelectrically and biomechanically enhanced tissue interface. This relatively more reliable and stable interface would be beneficial for many researchers exploring the neural basis of the insect locomotion with alleviated traumatic effects caused during adult stage insertions. In this article, we implant our electrodes into the indirect flight muscles of Manduca sexta. Located in the dorsal-thorax, these main flight powering dorsoventral and dorsolongitudinal muscles actuate the wings and supply the mechanical power for up and down strokes. Relative contraction of these two muscle groups has been under investigation to explore how the yaw maneuver is neurophysiologically coordinated. To characterize the flight dynamics, insects are often tethered with wires and their flight is recorded with digital cameras. We also developed a novel way to tether Manduca sexta on a magnetically levitating frame where the insect is connected to a commercially available wireless neural amplifier. This set up can be used to limit the degree of freedom to yawing “only” while transmitting the related electromyography signals from dorsoventral and dorsolongitudinal muscle groups.

Flight behavior of the rhinoceros beetle Trypoxylus dichotomus during electrical nerve stimulation

Neuronal stimulation is an intricate part of understanding insect flight behavior and control insect itself. In this study, we investigated the effects of electrical pulses applied to the brain and basalar muscle of the rhinoceros beetle (Trypoxylus dichotomus). To understand specific neuronal stimulation mechanisms, responses and flight behavior of the beetle, four electrodes were implanted into the two optic lobes, the brain's central complex and the ventral nerve cord in the posterior pronotum. We demonstrated flight initiation, turning and cessation by stimulating the brain. The change undergone by the wing flapping in response to the electrical signal was analyzed from a sequence of images captured by a high-speed camera. Here, we provide evidence to distinguish the important differences between neuronal and muscular flight stimulations in beetles. We found that in the neural potential stimulation, both the hind wing and the elytron were suppressed. Interestingly, the beetle stopped flying whenever a stimulus potential was applied between the pronotum and one side of the optic lobe, or between the ventral nerve cord in the posterior pronotum and the central complex. In-depth experimentation demonstrated the effective of neural stimulation over muscle stimulation for flight control. During electrical stimulation of the optic lobes, the beetle performed unstable flight, resulting in alternating left and right turns. By applying the electrical signal into both the optic lobes and the central complex of the brain, we could precisely control the direction of the beetle flight. This work provides an insight into insect flight behavior for future development of insect-micro air vehicle.

Convergent patterns of long-distance nocturnal migration in noctuid moths and passerine birds

Vast numbers of insects and passerines achieve long-distance migrations between summer and winter locations by undertaking high-altitude nocturnal flights. Insects such as noctuid moths fly relatively slowly in relation to the surrounding air, with airspeeds approximately one-third of that of passerines. Thus, it has been widely assumed that windborne insect migrants will have comparatively little control over their migration speed and direction compared with migrant birds. We used radar to carry out the first comparative analyses of the flight behaviour and migratory strategies of insects and birds under nearly equivalent natural conditions. Contrary to expectations, noctuid moths attained almost identical ground speeds and travel directions compared with passerines, despite their very different flight powers and sensory capacities. Moths achieved fast travel speeds in seasonally appropriate migration directions by exploiting favourably directed winds and selecting flight altitudes that coincided with the fastest air streams. By contrast, passerines were less selective of wind conditions, relying on self-powered flight in their seasonally preferred direction, often with little or no tailwind assistance. Our results demonstrate that noctuid moths and passerines show contrasting risk-prone and risk-averse migratory strategies in relation to wind. Comparative studies of the flight behaviours of distantly related taxa are critically important for understanding the evolution of animal migration strategies.

Airborne Radar Observations of the Flight Behavior of Small Insects in the Atmospheric Convective Boundary Layer

The vertical flight behavior of insects in the convective boundary layer (CBL) is examined by means of profiling airborne Doppler radar data collected in the central Great Plains in late spring. On fair-weather days, the CBL grows from the ground up in morning hours and matures at a depth of 1,000–1,500 m shortly after midday. It is well mixed by thermals bubbling up from near the surface. Nevertheless the CBL is dominated, over its entire depth, by well-defined regions of high insect concentrations, here referred to as insect plumes. This is inferred from radar, whose echoes in the CBL are largely caused by microinsects (<10 mm diameter). This study focuses on the vertical motion of the radar scatterers relative to the vertical air motion, in natural conditions. It is shown that insect plumes tend to be collocated with updrafts in the CBL and that microinsects tend to fall or fly down against the updrafts at an average speed of 0.5 ± 0.2 m/s. This estimate is based on a comparison of the close-range radar velocities, some 100 m above and below the aircraft, with the vertical air velocity measured at flight level. We hypothesize that the gregarious behavior of small insects in the CBL is explained by their tendency to oppose updrafts at a rate that is surprisingly proportional to the updraft strength. This finding is also strong evidence for the biotic nature of the echo plumes. This hypothesis is tested elsewhere by means of a simple numerical simulation.

A Simple Numerical Model of the Flight Behavior of Small Insects in the Atmospheric Convective Boundary Layer

We have combined aircraft and airborne Doppler radar observations to show that microinsects in the atmospheric convective boundary layer (CBL) are concentrated in rather well-defined plumes, that these plumes are generally found in thermals of rising air, and that the insects in those plumes oppose the updrafts at a rate that increases as the updrafts become stronger. In this paper, a simple numerical simulation of the airflow field and insect concentration in the CBL is developed. The model shows a consistency of the observed insect flight behavior with the presence of well-defined insect plumes in the otherwise well-mixed CBL and with the tendency of insects to cluster in updrafts. The model also explains the growth of insect plumes in the morning hours and their disappearance in the late afternoon. Other studies have proposed that the response of insects to being lofted high into the CBL is controlled by air temperature. Our simulation shows that a temperature-sensitive response alone does not yield well-defined plumes in regions of rising air currents. The observed flight strategy may be counterintuitive, but we suggest that it has a clear adaptive advantage.

Testing insect movement theory: empirical analysis of pest data routinely collected from agricultural crops

Observations of an insect's movement lead to theory on the insect's flight behaviour and the role of movement in the species’ population dynamics. This theory leads to predictions of the way the population changes in time under different conditions. If a hypothesis on movement predicts a specific change in the population, then the hypothesis can be tested against observations of population change. Routine pest monitoring of agricultural crops provides a convenient source of data for studying movement into a region and among fields within a region. Examples of the use of statistical and computational methods for testing hypotheses with such data are presented. The types of questions that can be addressed with these methods and the limitations of pest monitoring data when used for this purpose are discussed.

Effects of Ultraviolet-Absorbing Greenhouse Plastic Films on Flight Behavior of Bemisia argentifolii(Homoptera: Aleyrodidae) and Frankliniella occidentalis(Thysanoptera: Thripidae)

Several clear polyethylene film products, developed specifically for greenhouse use, have high UV-absorbing abilities, while allowing high transmission of visible light. We examined the effects of these plastics on insect flight behavior. Four high UV-blocking products from 2 manufacturers were compared with their respective standard plastics. Insect species tested were the whitefly, Bemisia argentifolii Bellows & Perring, and the western flower thrips, Frankliniella occidentalis (Pergande). In choice experiments, when insects were released from a black box at the center of 2 tunnels, sticky traps caught 85–94% of released whiteflies and 90–98% of released thrips inside standard tunnels when compared with UV-blocking tunnels. This indicates a distinct preference of both whiteflies and thrips to enter tunnels that transmit higher levels of UV light. In no-choice experiments, when insects were released at one end of a single tunnel covered with 1 type of plastic, there was no significant difference among types of plastic in the number of whiteflies or thrips caught, indicating that there was no obvious negative effect of UV-blocking plastic on the ability of insects to fly. These results indicate that greenhouse plastics may have significant influence on the initial attraction of insects into greenhouses. It will be important to study these effects in more detail to understand the mechanisms underlying UV-light taxis and the application of this phenomenon to management of insect pests in greenhouse crops.

Seasonal Radar and Meteorological Observations Associated with Nocturnal Insect Flight at Altitudes to 900 Meters

Nocturnal aerial insect flight activities between 30 and 900 m above ground level were monitored with 3-cm scanning radar during the spring, summer, and fall seasons of 1988 and 1989 in the Brazos River Valley of Burleson County near College Station, TX. Surface meteorological parameters were measured continuously with weather station instrumentation, and radiosondes carried aloft by weather balloons were used to measure upper-air temperatures and wind conditions. Aerial volume density patterns and flight behaviors observed with radar varied nightly because of the many biological and meteorological variables involved, but certain seasonal characteristics of insect flight behavior became apparent during the course of the research. Nightly local dispersal flights at dusk were the norm, especially during the summer. Large numbers of insects were typically airborne for 1 to 2 h beginning about one-half hour after sunset with some of them reaching altitudes of 800 m or more where wind speeds were typically greater than 30 km/h. Several apparent long-range migration-type insect movement events were observed in which insects were concentrated in layers in high-speed, low-level wind jets that were apparently associated with nocturnal upper-air temperature inversions. Migration-type movement of insects tended to be south to north in the spring and early summer and north to south in the fall.

Large Helicopter-Towed Net for Sampling Airborne Arthropods

ABSTRACT The development of a large helicopter-towed net for aerial sampling of arthropods in research of insect flight behavior and movement is described. The pyramidal, windsock-shaped net has a 5 m^ inlet and an air sampling rate of 3.2 x 10^ m^/h when towed at the designed airspeed of 64 km/h. This sampling rate is more than four times that reported in the literature for similar systems. With an apical angle of 25 deg or less in the large net, collected insects are efficiently funneled into a smaller compartmentalized collection net. The individual compartments of the collection net are constructed such that they can be sealed with styrofoam balls released by the pilot by remote control.

Orb-web visibility: the influence of insect flight behaviour and visual physiology on the evolution of web designs within the Araneoidea

Ecological differentiation among spiders that build orb-webs depends on the ability of webs both to absorb the kinetic energy of prey impact and to intercept prey (web visibility). Analyses of Diptera flying near webs show that Drosophila melanogaster Meigen avoids high-fibre-density orb-webs sooner than they avoid low-fibre-density webs. From analyses of the flight potential and visual capabilities of D. melanogaster, Trichoporosopon digitatum (Rondani) and Culex quinquesfasciatus Say, it seems surprising that orb-webs capture any prey at all. The thin diameter and refractive properties of web silks give spider webs a translucent quality that greatly reduces visibility. Web suspension in low- and diffuse-light environments, as well as against visually confused backgrounds, decreases one of the most important visual cues for prey, contrast between the web and its background. Among spiders that capture prey which are characterized by specialized visual and flight capabilities, oscillating webs and three-dimensional webs may enhance web capture effectiveness. Web oscillation and the static distortion of the plane of some orb-webs allow webs to ‘escape’ from the range of visual resolution of potential prey.

An infra-red remote sensing system for the active detection and automatic determination of insect flight trajectories (IRADIT)

AbstractA non-technical description is given of a new, powerful, low cost field system (Infra-red Active Determination of Insect Flight Trajectories or IRADIT) for detailed and automatic remote sensing studies of natural insect flight behaviour. The special requirements and difficulties of the detection problem are defined. A series of examples of field devices and techniques are presented to illustrate the key factors of the optical sensing and tracking of insects in flight. In the finally adopted IRADIT system, flying insects are differentially illuminated, under all natural light conditions, by an intense beam of pulsed near-infra-red radiation and detected using a shuttered image intensifier linked with a video camera operating at a rate of 50 frames per second. Immediate fully-automatic determination of the flight trajectories of several simultaneously detected insects was achieved, at this same high rate and in the presence of sky background photon noise, by processing the video signals with electronic circuits and a microcomputer. Flight trajectories are influenced by the local wind, whose vector must be subtracted to study insect flight behaviour. This was achieved by the use of a specially developed sensitive three-vector vane anemometer, providing digital data to the microcomputer at a minimum rate of 5 Hz. In tests of the prototype IRADIT-anemometer system in the field, insects with wing area of only 1·5 mm2 and flying against the midday sky were readily tracked at ranges up to 15 m. A range of at least 100 m is expected for nocturnal moth tracking.

High School Student's Experiment Goes into Space

The third flight of NASA's Space Shuttle, launched on March 22, had stowaways on board. In addition to the crew members and the normal assortment of flora and fauna that live on and in the human body, velvetbean caterpillar moths and honeybee drones were present for the historic trip into space. They are the subjects of an experiment designed by a Minnesota high school student. Todd E. Nelson is an 18-year-old senior at Southland Public School, Adams, Minnesota, and his experiment, Insects in Flight Motion Study, was chosen as the first student experiment to be placed on board a Space Shuttle flight. Nelson is one of ten finalists in the NASAsponsored National Space Shuttle Student Involvement Project for Secondary Schools. Developed in cooperation with the National Science Teachers Association, the project seeks to stimulate student interest in science and technology. The experiment is designed to pro vide data on the flight behavior in zero gravity of two species of flying insects with differing ratios of body mass to wing area. The experiment calls for placing a container aboard the Space Shuttle, stored in a drawer in the mid deck of the Orbiter. An astronaut would then remove the container (holding ten specimens of each species of insect), attach it to the wall of the mid deck, and observe their behavior. Their flight patterns would be filmed against a background grid. After filming, the astronaut would return the insects, still in their container, to the locker for the return flight and later analysis. While insect flight behavior has been studied before, it was for only a brief period of about 20 seconds in-parabolic flight. The Avionics Division of Honeywell, Inc. of Minneapolis, at the invitation of NASA, agreed to sponsor development of Nelson's experiment. Dr. Robert Peterson of the Honeywell Corporation and Nelson have worked together for the six months prior to the Shuttle at Honeywell's headquarters, preparing the experiment for flight. In addition, Honeywell has provided travel funds to enable Nelson to work with Peterson and to attend the liftoff, analyze data, and prepare a final report. The overall goal of the NASA project is to stimulate the study of science and engineering by engaging students in an annual competition to develop experiments suitable for flight aboard the Space Shuttle. The competition is open to students in grades 9 to 12, enrolled in American public, private, parochial, and overseas schools. Regional winners (about 200) and their teachers were invited to attend conferences held at NASA field centers where the students presented their proposals to teams of scientists. Based on advice provided by the scientists, regional winners made minor revisions in their proposals prior to final judging in Washington, D.C. The experiments of the remaining winners of the 1980-81 competition are being readied for inclusion on future Space Shuttle flights, as space is available. It is not surprising that seven of the ten winning proposals involve problems in biology. The titles include Biofeedback, Growth of Porifera in Zero Gravity, and Effects of Weightlessness on Arthritis. Information about future competitions may be obtained by writing to: Shuttle Student Involvement Project, NSTA, 1742 Connecticut Avenue, N.W., Washington, D.C. 20009.

The colonization cycle of freshwater insects.

This paper summarizes the recent research on problems of the so-called colonization cycle as one aspect of the migration and flight behaviour of freshwater insects. New results are presented and the applied methods described and discussed. In general the research on this phenomenon shows that the colonization cycle can not only be seen as a type of compensatory flight behaviour, but also as an expression of the winter survival strategy of water insects in high mountainous areas. It opens up the possibility of exploiting ecologically different biotopes such as living in coastal streams and oligohaline brackish water estuaries.

The role of aircraft in the management of insect populations in crops in the year 2000

Although 2000 AD is but 20 years away, even so this is a long period in terms of the rate of recent technological development. My remarks about the possible future state of this subject must therefore be somewhat speculative. The projections will be based, however, on research carried out over the past 10 years, and I hope this will provide an element of usefulness.I shall refer to both agricultural and forestry crops. Our most extensive agricultural experience has been with cotton and its pests in the Sudan, particularly the cotton bollworm moth; and with cereals in the UK, particularly cereal aphids. Our forestry experience has been with softwoods and the spruce budworm moth in eastern Canada, and with lodge-pole pine forests and the pine beauty moth in Scotland. In terms of techniques our experience has ranged over ground-based and airborne radars, a full range of ground and airborne meteorological instrumentation, the study of insect flight behaviour by sensitive infra-red opto-electronic devices, the turbulent dispersal of spray droplets and their deposition on foliage and insects, the study and quantification of insect population dynamics, and the use of many biological techniques, including suction traps and light traps.

The effect of bioclimate on the communication system of night-flying moths

Detection of moths and plants by infrared radiation (IR) is possible by night-flying moths. The thermal radiation emissivity of green plants is high (0.96) and that of a plowed field low (0.28). Four elements of the biosphere, temperature, atmospheric moisture, CO2 and O3 could hinder transmission.Corn earworm flight temperatures rise 3°C above ambient and at 25°C it would be broadcasting a chopped IR frequency of approximately 31 tetracycles. Water vapor is the principal attenuator of IR radiation. Data shows that moth activity decreases sharply with increases in actual water content of the air. Optimum temperatures and humidity are most likely to occur in spring and early summer between 21:00 and 04:00 hr. This coincides with the period of maximum corn earworm activity. Data indicates an inverse relationship between 03 and insect activity. Data from 4 sequentially programmed light traps indicate that flight behavior of insects is timed for the period of optimum reception by insect sensors.