Changes In Wingbeat Frequency Research Articles

Extremely Low-Frequency Electromagnetic Fields Entrain Locust Wingbeats.

Extremely low-frequency electromagnetic fields (ELF EMFs) have been shown to impact the behavior and physiology of insects. Recent studies have highlighted the need for more research to determine more specifically how they affect flying insects. Here, we ask how locust flight is affected by acute exposure to 50 Hz EMFs. We analyzed the flights of individual locusts tethered between a pair of copper wire coils generating EMFs of various frequency using high-speed video recording. The mean wingbeat frequency of tethered locusts was 18.92 ± 0.27 Hz. We found that acute exposure to 50 Hz EMFs significantly increased absolute change in wingbeat frequency in a field strength-dependent manner, with greater field strengths causing greater changes in wingbeat frequency. The effect of EMFs on wingbeat frequency depended on the initial wingbeat frequency of a locust, with locusts flying at a frequency lower than 20 Hz increasingtheir wingbeat frequency, while locusts flying with a wingbeat frequency higher than 20 Hz decreasing their wingbeat frequency. During the application of 50 Hz EMF, the wingbeat frequency was entrained to a 2:5 ratio (two wingbeat cycles to five EMF cycles) of the applied EMF. We then applied a range of ELF EMFs that were close to normal wingbeat frequency and found that locusts entrained to the exact frequency of the applied EMF. These results show that exposure to ELF EMFs lead to small but significant changes in wingbeat frequency in locusts. We discuss the biological implications of the coordination of insect flight in response to electromagnetic stimuli. © 2021 Bioelectromagnetics Society.

A Novel Methodology For Recording Wing Beat Frequencies of Untethered Male and Female Aedes aegypti.

Aedes aegypti is a vector of many significant arboviruses worldwide, including dengue, Zika, chikungunya, and yellow fever viruses. With vector control methodology pivoting toward rearing and releasing large numbers of insects for either population suppression or virus-blocking, economical remote (sentinel) surveillance methods for release tracking become increasingly necessary. Recent steps in this direction include advances in optical sensors that identify and classify insects based on their wing beat frequency (WBF). As these traps are being developed, there is a strong need to better understand the environmental and biological factors influencing mosquito WBFs. Here, we developed new untethered-subject methodology to detect changes in WBFs of male and female Ae. aegypti. This new methodology involves directing an ultrasonic transducer at a free-flying subject and measuring the Doppler shift of the reflected ultrasonic continuous wave signal. This system's utility was assessed by determining its ability to confirm previous reports on the effect of temperature, body size, and age on the WBFs generated from acoustic or optical-based experiments. The presented ultrasonic method successfully detected expected trends for each factor for both male and female Ae. aegypti without the need for subject manipulation and potential impediment of natural flight dynamics due to tethering. As a result, this ultrasonic methodology provides a new method for understanding the environmental and physiological determinants of male and female WBFs that can inform the design of remote mosquito surveillance systems.

Exploring the relationship between flapping behaviour and accelerometer signal during ascending flight, and a new approach to calibration

We understand little about the energetic costs of flight in free‐ranging birds, in part because current techniques for estimating flight energetics in the wild are limited. Accelerometry is known to estimate energy expenditure through body movement in terrestrial animals, once calibrated using a treadmill with chamber respirometry. The flight equivalent, a wind tunnel with mask respirometry, is particularly difficult to instigate, and has not been applied to calibrate accelerometry. We take the first steps in exploring a novel method for calibrating accelerometers with flight energy expenditure. We collected accelerometry data for Harris's Hawks Parabuteo unicinctus flying to varying heights up to 4.1 m over a small horizontal distance; the mechanical energy expended to gain height can be estimated from physical first principles. The relationship between accelerometry and mechanical energy expenditure was strong, and while a simple wing flapping model confirmed that accelerometry is sensitive to both changes in wing beat amplitude and frequency, the relationship was explained predominately by changes in wing beat frequency, and less so by changes in amplitude. Our study provides initial, positive evidence that accelerometry can be calibrated with body power using climbing flights, potentially providing a basis for estimating flapping flight metabolic rate at least in situations of altitude gain.

A role for acoustic distortion in novel rapid frequency modulation behaviour in free-flying male mosquitoes

We describe a new stereotypical acoustic behaviour by male mosquitoes in response to the fundamental frequency of female flight tones during mating sequences. This male-specific free-flight behaviour consists of phonotactic flight beginning with a steep increase in wing-beat frequency (WBF) followed by rapid frequency modulation (RFM) of WBF in the lead up to copula formation. Male RFM behaviour involves remarkably fast changes in WBF and can be elicited without acoustic feedback or physical presence of the female. RFM features are highly consistent, even in response to artificial tones that do not carry the multi-harmonic components of natural female flight tones. Comparison between audiograms of the robust RFM behaviour and the electrical responses of the auditory Johnston's organ (JO) reveals that the male JO is tuned not to the female WBF per se but, remarkably, to the difference between the male and female WBFs. This difference is generated in the JO responses as a result of intermodulation distortion products (DPs) caused by non-linear interaction between male-female flight tones in the vibrations of the antenna. We propose that male mosquitoes rely on their own flight tones in making use of DPs to acoustically detect, locate and orientate towards flying females. We argue that the previously documented flight-tone harmonic convergence of flying male and female mosquitoes could be a consequence of WBF adjustments so that DPs generated through flight-tone interaction fall within the optimal frequency ranges for JO detection.

Signalling with clear wings during territorial behaviour and courtship ofChlorocypha cancellata(Odonata, Chlorocyphidae)

The reproductive behaviour of the damselfly Chlorocypha cancellata (Chlorocyphidae) was filmed at 600 frames per second. Different flight styles including straight, forward flight, threat and courtship display were analysed with respect to changes in wing beat frequency and phase relationships of fore and hind wings. The analysis revealed significant differences in the flight style between non-escalated and escalated threat display as well as changes in the wing beat frequency of a male during courtship dependant on the behaviour of the female. This is the first evidence suggesting that odonate species with clear wings can use specialized flight modes for intraspecific signalling.

Sexual dimorphism in wing beat frequency in relation to eye span in stalk-eyed flies (Diopsidae)

Although male ornaments may provide benefits to individuals bearing them, such structures may also entail fitness costs. Selection should favour aspects of the phenotype that act to reduce such costs, yet such compensatory traits are often ignored in studies of sexual selection. If a male ornament increases predation risk via reduced locomotor performance, then there may be selection for changes in morphological traits to compensate for behavioural or biomechanical changes in how individuals use their morphology (or both). We took a comparative approach aiming to test whether changes in wing beat frequency are evolutionarily correlated with increases in male ornamentation across stalk-eyed fly species. Previous studies have shown that increased male eye span is evolutionarily correlated with increased wing size; thus, we tested whether there is additional compensation via increases in size-adjusted wing beat frequency. The results obtained revealed that relative wing beat frequency is negatively related to relative eye span in males, and sexual dimorphism in wing beat frequency is negatively related to dimorphism in eye span. These findings, in addition to our finding that eye span dimorphism is positively related to aspect ratio dimorphism, suggest that male stalk-eyed flies compensate primarily by increasing wing size and shape, which may then have resulted in the subsequent evolutionary reduction in wing beat frequency. Thus, exaggerated ornaments can result in evolutionary modifications in wing morphology, which in turn lead to adjustments in flapping kinematics, illustrating the tight envelope of trade-offs when compensating for exaggerated ornaments.

Effects of flight behaviour on body temperature and kinematics during inter‐male mate competition in the solitary desert bee Centris pallida

Abstract. Body temperatures and kinematics are measured for male Centris pallida bees engaged in a variety of flight behaviours (hovering, patrolling, pursuit) at a nest aggregation site in the Sonoran Desert. The aim of the study is to test for evidence of thermoregulatory variation in convective heat loss and metabolic heat production and to assess the mechanisms of acceleration and forward flight in field conditions. Patrolling males have slightly (1–3 °C) cooler body temperatures than hoverers, despite similar wingbeat frequencies and larger body masses, suggesting that convective heat loss is likely to be greater during patrolling flight than during hovering. Comparisons of thorax and head temperature as a function of air temperature (Ta) indicate that C. pallida males are thermoregulating the head by increasing heat transfer from the thorax to the head at cool Ta. During patrolling flight and hovering, wingbeat frequency significantly decreases as Ta increases, indicating that variation in metabolic heat production contributes to thermal stability during these behaviours, as has been previously demonstrated for this species during flight in a metabolic chamber. However, wingbeat frequency during brief (1–2 s) pursuits is significantly higher than during other flight behaviours and independent of Ta. Unlike most other hovering insects, C. pallida males hover with extremely inclined stroke plane angles and nearly horizontal body angles, suggesting that its ability to vary flight speed depends on changes in wingbeat frequency and other kinematic mechanisms that are not yet described.

From Molecules to Mating Success: Integrative Biology of Muscle Maturation in a Dragonfly

2 SYNOPSIS. Dragonflies begin adult life as comparatively weak fliers, then mature to become one of nature's ultimate flying machines. This ontogenetic transition provides an opportunity to investigate the relationship between life history, phenotypic plastic- ity, and changing ecological demands on organismal performance. Here we present an overview of a wide-ranging study of dragonfly muscle maturation that reveals i) ecological changes in the need for efficient versus high-performance flight, ii) organ- ism-level changes in performance, thermal physiology, locomotor mechanics, and en- ergy efficiency, iii) tissue-level changes in muscle ultrastructure and sensitivity to ac- tivation by calcium, and iv) molecular-level changes in the Lsoform composition of a calcium regulatory protein in flight muscle (troponin-T). We discuss how these phe- nomena may be causally related, and thereby begin to show linkages across many levels of biological organization. In particular, we suggest that alternative splicing of troponin-T mRNA is an important component of the of muscle contractile function for developmental changes in wingbeat frequency and ecological demands on flight performance. Age-variable gearing of muscle function allows energetically eco- nomical flight during early adult growth, whereas power output is maximized at ma- turity when aerial competition determines success during territoriality and mating.

Interneurons in the flight system of the locust: Distribution, connections, and resetting properties

The organization and functional properties of interneurons in the flight system of the locust, Locusta migratoria, were investigated by using intracellular recording and staining techniques. Interneurons were found to be distributed within the three thoracic and the first three abdominal ganglia, and they could be subdivided into three organizational categories: (1) members of one of two serially homologous groups controlling either the forewing or the hindwing, (2) unique individuals with no known homologues in other ganglia, and (3) members of a set of serial homologous in the metathoracic and first three abdominal ganglia. Interneurons in the last two categories influenced both forewing and hindwing motoneurons in a similar manner. Thus interneuronal organization is not characterized by two distinct homologous groups of interneurons for the separate control of forewing and hindwing motor activity. Flight interneurons may also form two separate functional categories: (1) those making short latency connections to motoneurons (premotor interneurons), and (2) those which reset the flight rhythm when depolarized by brief current pulses (pattern generator interneurons). None of the ten premotor interneurons we identified influenced the flight rhythm when depolarized and none of the three groups of pattern generator interneurons were found to form short latency connections with motoneurons. This separation of function may allow phase-shifts in motor output for flight control without changes in wingbeat frequency. Pattern generator interneurons influence motor output to both forewings and hindwings. Thus we conclude that the flight rhythm is generated in a distributed neuronal oscillator driving both the pairs of wings. The organization of flight interneurons is considerably more complex than predicted from existing models of the flight system, or anticipated from the relative simplicity of the motor output. Our finding of homologous sets of interneurons in the abdominal ganglia supports the notion that insect flight evoked from a behavior using appendages distributed along the thorax and the abdomen. Thus the organization of flight interneurons may reflect an interneuronal system which controlled the behavior from which flight evolved.

Development of mitochondrial and contractile components of the flight muscle in adult tsetse flies, Glossina morsitans

Estimates have been made of the phospholipid, the water, and the cytochrome- c content of the dorsal longitudinal flight muscles of the tsetse fly, and of the total non-fatty dry weight of the thorax, at different stages of adult development. The results have served as a basis for the partitioning of the dry weight of flight muscle into its three main components—contractile protein, mitochondrial protein, and phospholipid. Development is shown to involve a twofold increase in the amount of contractile protein, and a threefold increase in the amount of mitochondrial protein. These changes are discussed in relation to associated changes in wingbeat frequency.

Effects of ambient temperature, humidity, and age on wing-beat frequency of Periplaneta species

Wing-beat frequency of 2-week-old male Periplaneta americana cockroaches was measured during tethered flight at ambient temperatures from 19 to 35°C and 50 and 95% r.h. Between 19 and 27°C the frequency increased at a nearly constant rate (0·6 Hz/deg at 50% r.h.; 0·7 Hz/deg at 95% r.h.), but the rate of increase decreased markedly between 27 and 35°C. This decline differed from results of past investigations of wing-beat frequency for this species. Wing-beat frequencies at 95% r.h. were significantly higher than those at 50% r.h. for ambient temperatures between 27 and 35°C. reductions in wing-beat frequency at high temperatures and differences in wing-beat frequency between 50 and 95% r.h. may reflect decreases in internal thoracic temperature resulting from cuticular water loss. P. americana females lack the capacity for sustained free flight, but were tested in tethered flight in the same manner as males. Wing-beating lasted only 3 to 8 sec compared to 5 to 6 min for males. However, wing-beat frequency did not differ significantly from males except at one temperature and humidity combination, 35°C and 95% r.h. Failure of females to sustain wing-beating may be due to the lack of available energy in the flight muscles. Wing-beat frequencies among 2-week-old P. australasiae, P. brunnea, and P. fuliginosa males in tethered flight at 19 to 35°C and 50% r.h. were similar to P. americana males. P. australasiae differed significantly from P. brunnea over the entire range of temperatures, but only minor differences occurred among the other species. As they matured, males of the four species showed similar changes in wing-beat frequency at 25°C, 50% r.h., and only small consistent differences between species occurred. Wing-beat frequency could not be determined 1 to 3 days after eclosion because no wing beating occurred. On days 4 to 6 the frequency was approximately the same for all species, 23 Hz. Frequency increased to approximately 26·5 Hz on day 7 and by day 14 reached a maximum level of 30 to 31 Hz which was maintained until the termination of the experiment on day 35.

The nervous control of the indirect flight muscles of the honey bee

1. Changes in wingbeat frequency and action potential frequency were highly correlated in response to changes in body temperature. Wingbeat frequencies of 50 to 175 Hz occurred simultaneously with action potential frequencies of 9 to 26 Hz in response to changes in body temperature over a range of 16 to 34° C. 2. Weighting the wings lowered the wingbeat frequency and the action potential frequency simultaneously. 3. The oxygen consumed per action potential was constant before and during flight (1.16 and 1.14 μl/g/min respectively). The average in-flight oxygen consumption was 1171 μl/g/min at standard temperature and pressure. 4. Action potentials in the dorsoventral muscles occurred during a preferred phase of the wingcycle. Action potentials in the dorsolongitudinal muscles usually occurred with no significant phase preference to the wingbeat. 5. The role of the dorsoventral muscles as a timer of the flight system is discussed in light of the results presented.

Duration and frequency of wing beat in the aging house fly, Musca domestica L.

1. The age-related changes in wing beat frequency and duration of flight were studied in senescent male and female NAIDM house flies.2. The average wing beat frequency increases to a maximum by the fifth day in female and by the fourth day in male house flies.3. Duration of flight shows a steady, day-to-day decline with age. In females, this falls from 500 minutes for one-day-old to 110 minutes for 22-day-old flies. For males, this drop is more striking, with duration of flight falling from 420 minutes in one-day-old to 63 miiutes for nine-day-old males.4. These findings correspond to and confirm quantitatively previously reported data for wing loss and similar age-related changes in enzyme and coenzyme content in the flight muscle of senescent house flies.