Foraging and mate-finding in the silver Y moth, Autographa gamma (Lepidoptera: Noctuidae) under the risk of predation

Animal foraging and reproductive behaviour is influenced by other simultaneous demands such as predator avoidance. The trade-offs between these demands may depend on sex or mating experience. This study demonstrates that the olfactory-mediated foraging and mate-seeking behaviours in the silver Y moths, Autographa gamma , are affected by auditory cues mimicking their bat predators. Both males and females changed their foraging behaviour under simulated predation risk. Fewer moths reached the odour source following sound stimulation and the time to find the odour source increased by up to 250%. However, there were no significant differences between male and female ability to reach the plant odour source or the duration of the flight towards the source when stimulated with ultrasound. Hence females are not more cautious than males when observed in the same behavioural context. Risk-taking in males was independent of whether they were flying toward a flower odour or sex pheromones having equal attractive value. This indicates that the trade-off between olfactory and acoustic cues is independent the type of odour. Mated females were not as strongly affected by sound as non-mated, indicating that flower odours have a higher adaptive value for mated females, suggesting that some processes following mating experience influence the trade-off between flower odours and simulated bat sounds.     

Behavioral and reproductive effects of ultrasound on the Indian meal moth, Plodia interpunctella

The daily activity patterns of adult movement, female calling, and mating of the Indian meal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), were examined both in the absence and presence of ultrasound. Moths were exposed to ultrasound from a commercial ultrasonic device (Cix 0600) that produces constant sound patterns, and from a device developed at Kansas State University (KSU device) that produces random sound patterns. Daily activity patterns of adult movement, female calling, and mating followed a similar trend in the absence or presence of ultrasound. Female calling and mating, both in the absence and presence of ultrasound, primarily occurred during scotophase (21.00–07.00 hours). Ultrasound from the two devices significantly reduced the frequency of female calling and mating relative to unexposed moths. Consequently, the number of spermatophores transferred by males to females and egg production were lower in females exposed to ultrasound compared with unexposed females. In the absence of ultrasound, female P. interpunctella mated 2.9 times, resulting in 2.8 spermatophores/female. In the presence of ultrasound from the Cix 0600 device, a female mated 2.1 times and had 1.7 spermatophores. Corresponding values for the KSU device were 1.9 and 1.4, respectively. In the absence of ultrasound, 78% of the matings lasted 30–90 min, whereas in the presence of ultrasound 45–58% of the matings lasted either less than 30 min or more than 90 min. Moths exposed to ultrasound laid 96–130 eggs female^?1 compared with 229 eggs female^?1 for unexposed moths. Ultrasound did not affect the pre‐oviposition period and adult longevity of P. interpunctella.     

An analysis of anemotactic flight in female moths stimulated by host odour and comparison with the males' response to sex pheromone

ABSTRACT. The flight pattern of mated female navel orangeworm moths, Amyelois transitella (Walker), responding to odour from potential larval hosts is zigzagging upwind flight. However, at times these moths are capable of flying nearly directly upwind towards the odour source (track angles near 0). This response indicates that these females are capable of very accurate anemotactic control of their heading or course angle, since small angular errors in this measure would translate into larger deviations from direct upwind flight. Males of this species exhibit flight patterns similar to those of females, including track angles clustered about 0 when flying upwind to a source of the female-produced pheromone, but under these experimental conditions they flew with a higher average airspeed than the females. When females lose contact with an odour plume they initiate a well-defined programme of cross-wind counterturning or casting, which may normally increase their chances of retrieving contact with that plume when the wind direction shifts. The resultant track angles of females increase significantly by 0.8 s after plume loss, indicating that the female has initiated changes in both her course angle and airspeed. By 1 s after plume loss the females' track angles are no longer unimodally distributed about 0, but are bimodally distributed about -90 and +90. Males responded more rapidly to the loss of a pheromone plume, demonstrating a significant change in track angle 0.4 s after plume loss. Overall, female and male A.transitella exhibited remarkably similar anemotactic flight manoeuvres during upwind flight to odour sources as well as after plume loss.     

Mating frequency in dispersing potato tuber moth, Phthorimaea operculella, and its influence on the design of refugia to manage resistance in Bt transgenic crops

Mating of potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), was investigated in relation to the dispersal of males in laboratory and field trials. The effect of stimulating the flight of males to light sources in a large cage on their mating ability was estimated for three age groups, and compared with similar estimates for confined moths. Although the mating of males declined with ages of up to 15 days, simulated dispersal had no effect on subsequent mating when the males were paired with virgin females. The dispersal of male moths was also categorised by the initial flight activity of untethered moths to a light source. Scores for poor, moderate, and good flight provided a repeatable measure of initial male flight activity, but the degree of activity was not related to their subsequent mating ability. In the field, virgin female potato tuber moths were tethered at various distances from the edge of isolated potato crops and then dissected to determine their mating status. Female mating frequency averaged 75% at the crop margin, remained above 50% up to 200 m, and then declined to 19% at 360 m from the margin. Derivation of the mating probability for an individual male potato tuber moth confirmed earlier work by other researchers that has indicated a tendency for dispersal prior to mating, and that males retain their ability to mate as they disperse from a crop. The influence of dispersal and mating on gene flow between crops, and its potential effects on refuge size required to minimise the development of resistance to Bt transgenic potato crops was examined.     

Simultaneous monitoring of flight and oviposition of individual velvetbean caterpillar moths

ABSTRACT. A 'pivot' flight actograph was combined with a rolling oviposition surface to characterize the flight and oviposition behaviour of velvetbean caterpillar moths, Anticarsia gemmatalis Hubner. Tethered, caged control females laid significantly more eggs that those flown on the actograph. Mated females laid more eggs than unmated ones. However, mating did not affect longevity nor fight frequency and duration. Laboratory-reared and wild-type females also did not differ signficantly in longevity and flight. Both laboratory and wild mated females laid most of their eggs during the first 7 days whereas unmated ones delayed their oviposition. None of the female types produced a definite hourly, daily or lifetime pattern in flight frequency or duration. Of the 7672 recorded flights, about 3% were greater than 0.5 h. 'Long' flights (>0.5h) were made by some females before oviposition, as in colonization migration, but most interspersed flight with oviposition, as in extended search migration.     

Hearing and evasive behaviour in the greater wax moth, Galleria mellonella (Pyralidae)

Greater wax moths (Galleria mellonella L., Pyraloidea) use ultrasound sensitive ears to detect clicking conspecifics and echolocating bats. Pyralid ears have four sensory cells, A_1?4. The audiogram of G. mellonella has best frequency at 60 kHz with a threshold around 47 dB sound pressure level. A₁ and A₂ have almost equal thresholds in contrast to noctuids and geometrids. A₃ responds at + 12 to + 16 dB relative to the A₁ threshold. The threshold data from the A‐cells give no indication of frequency discrimination in greater wax moths. Tethered greater wax moths respond to ultrasound with short‐latency cessation of flight at + 20 to + 25 dB relative to the A₁ threshold. The behavioural threshold curve parallels the audiogram, thus further corroborating the lack of frequency discrimination. Hence, the distinction between bats and conspecifics is probably based on temporal cues. At a constant duty cycle (percentage of time where sound is on) the pulse repetition rate has no effect on the threshold for flight cessation, but stimulus duration affects both sensory and behavioural thresholds. The maximum integration time is essentially the same: 45 ms for the A₁‐cell and 50–60 ms for the flight cessation response. However, the slopes of the time‐intensity trade‐off functions are very different: ? 2.1 dB per doubling of sound duration for the A₁‐cell threshold, and ? 7.2 dB per doubling of sound duration for the behavioural threshold. The significance of the results for sexual acoustic communication as well as for bat defence is discussed.     

甘蓝夜蛾Mamestra brassicae Linnaeus飞行能力研究

【目的】测定日龄、性别、交配等因素对农业迁飞性害虫甘蓝夜蛾Mamestra brassicae Linnaeus飞行能力的影响,为其迁飞行为研究和异地测报提供理论依据。【方法】在气温为(24±1)℃、相对湿度为75%±5%的实验室环境下,利用飞行磨系统对甘蓝夜蛾实验室种群1~5日龄未交配个体、已交配的3日龄个体以及野外迁飞种群分别进行连续24 h吊飞测试,记录其累计飞行时间、累计飞行距离、平均飞行速率等参数。【结果】甘蓝夜蛾实验室种群的飞行能力随日龄增长而变化,初羽化时即具有较强的飞行能力,2~3日龄达到峰值,4~5日龄的飞行能力显著下降;雌性甘蓝夜蛾的飞行能力强于雄性甘蓝夜蛾;交配的甘蓝夜蛾平均飞行速率显著小于处女甘蓝夜蛾,但二者的平均飞行时间和飞行距离均无显著差异。此外,渤海湾迁飞种群中晚季节南迁种群的飞行能力显著强于早季节北迁种群和过渡种群。【结论】日龄和交配状态是影响甘蓝夜蛾飞行能力的关键因素。     

Behavioural context regulates dual function of ultrasonic hearing in lesser waxmoths: bat avoidance and pair formation

Abstract.  Ultrasonic hearing in moths evolved to detect bat echolocation cries and has been co-opted into the mating system of some species. Some moths evade or approach ultrasonic stimuli that overlap in their spectral and temporal features. The present study addressed the evaluation of ultrasonic stimuli by lesser waxmoths, a species in which ultrasonic hearing functions in bat evasion and pair formation. Playback experiments show that the role of different stimulus features varies with behavioural context. Flying moths have a single evasive response, which is performed mainly on the basis of pulse length and stimulus power: they dive upon hearing loud pulses ≥ 1 ms in length, and respond more strongly to high-power stimuli above that pulse length. Female moths walking on the ground respond with positive phonotaxis mainly on the basis of pulse rate by orienting toward pulses delivered at rates ≥ 30 pulses s⁻¹. Consequently, moths on the ground approach stimuli that elicit evasion when detected in flight. However, the different responses given to stimulus features by flying and walking moths match the distinguishing features of bat cries and conspecific males in both contexts. Stimulus evaluation, modified by behavioural context, gives lesser waxmoths the flexibility to show appropriate evasion or approach responses to stimuli that overlap in their features.     

Olfactory orientation responses of the eucalyptus woodborer, Phoracantha semipunctata, to host plant in a wind tunnel

The eucalyptus woodborer, Phoracantha semipunctata Fabricius (Coleoptera: Cerambycidae), attacks mainly species of Eucalyptus (Myrtaceae). This study investigated walking and flight behaviour of P. semipunctata males and females exposed to an odour plume originating from a log of E. globulus placed vertically in the upwind end of a wind tunnel. In control experiments, beetles were exposed to a PVC drainpipe in the same position as the log, providing a visual stimulus without host‐tree odour. No statistical differences were found between behavioural responses of either sex when exposed to the log or PVC pipe. No beetles landed on the PVC pipe, whereas 49% of the beetles exposed to host‐tree odour plume landed on the log. Beetles aged over 24 days after emergence from the host tree were more responsive than beetles aged 20–24 days, and accounted vor 86% of the beetles that landed on the log. While walking, host‐tree odour affected the behaviour of the beetles that landed on the log as follows: upwind movement and path linearity increased, whereas turning rate, stopping frequency, mean stopping time and time to take‐off flight decreased. During flight, host‐tree odour affected the behaviour of the beetles that landed on the log as follows: increased upwind flight, turning rate, flight time, flight distance, and decreased flight speed. For beetles that never lost contact with the odour plume, flight progressed upwind with narrow zigzags, and showed higher directedness upwind, path linearity, faster flight speed and lower turning rate than for beetles that lost contact with the odour plume. After loosing contact with the plume, beetles tended to decrease their upwind progression, exhibiting a sharp turn or quick counterturns followed by crosswind or downwind excursions. This led to regaining contact with the odour plume and resumed upwind progression at higher speed provided they flew within the boundaries of the plume. The results showed that host‐tree odour affects both walking and flight behaviour of P. semipunctata beetles, inducing a more directed upwind movement and landing on the visual stimulus of a tree trunk.     

Concurrent modulation of neuronal and behavioural olfactory responses to sex and host plant cues in a male moth

Mating has profound effects on animal physiology and behaviour, not only in females but also in males, which we show here for olfactory responses. In cotton leafworm moths, Spodoptera littoralis, odour-mediated attraction to sex pheromone and plant volatiles are modulated after mating, producing a behavioural response that matches the physiological condition of the male insect. Unmated males are attracted by upwind flight to sex pheromone released by calling females, as well as to volatiles of lilac flowers and green leaves of the host plant cotton, signalling adult food and mating sites, respectively. Mating temporarily abolishes male attraction to females and host plant odour, but does not diminish attraction to flowers. This behavioural modulation is correlated with a response modulation in the olfactory system, as shown by electro-physiological recordings from antennae and by functional imaging of the antennal lobe, using natural odours and synthetic compounds. An effect of mating on the olfactory responses to pheromone and cotton plant volatiles but not to lilac flowers indicates the presence of functionally independent neural circuits within the olfactory system. Our results indicate that these circuits interconnect and weigh perception of social and habitat odour signals to generate appropriate behavioural responses according to mating state.     

Sexual differences in the flight performance of the oriental fruit moth, Cydia molesta

Cydia molesta Busck (Lepidoptera: Tortricidae), a major pest of stone fruits and an increasingly important late season pest of apple, is predominately monitored by pheromone trapping of male moths. We investigated flight performance in relation to sex, age, and mating status using computer-linked flight mills, and also examined the relationship between female flight and reproduction. The crepuscular flight pattern of the experimental moths in relation to photointensity was very similar to that reported from field studies. Female moths significantly outperformed males in all measured flight parameters including total distance flown, distance of longest single flight, and velocity. The proportion of long-flying females (categorised as those completing an unbroken flight of greater than 1 km) was three to six times greater than that of males. Female flight performance was not related to mating status, but mated males displayed significantly greater flight than unmated males. The maximal flight period of mated females commenced on the third day after eclosion, following 30% egg deposition. Male flight was not significantly related to age. The data suggest that a limited proportion of the population, in particular females, may have the capacity to make inter-orchard flights. The limitations of monitoring C. molesta populations in apple orchards solely by pheromone trapping of males are discussed.     

Multiple mating of male and female codling moth (Lepidoptera: Tortricidae) in apple orchards treated with sex pheromone

Studies were conducted with codling moth, Cydia pomonella L., to evaluate the mating status of male and female moths in apple, Malus domestica (Borkhausen), orchards treated with and without sex pheromone dispensers. Laboratory studies first examined the effect of multiple mating of male and female moths on female fecundity and egg fertility. Females that had mated three times had a significantly higher fecundity than singly mated moths. Sequential mating by male moths had no effect on the fecundity of female moths or egg fertility. However, male moth age did impact female fecundity, with significantly fewer eggs laid after mating with virgin 1- versus 3-d-old males. The mean size of the first spermatophore transferred by males was significantly larger than all subsequent spermatophores. Classifying spermatophores based on size was used in field sampling to categorize the mating status of the female's partner. The proportion of mated females with small spermatophores (partner had previously mated) was significantly higher in treated versus untreated orchards. The proportion of female moths caught in traps baited with pear ester that were virgin was low (相似文献   

黄地老虎飞行能力研究

黄地老虎Agrotis segetum是一种重要的农业迁飞性害虫,研究飞行生物学对明确其迁飞机理有重要意义。本项研究利用昆虫飞行磨系统对黄地老虎的飞行能力进行了测定。对实验室种群飞行能力的测定结果表明:1日龄成虫的飞行能力最弱;3日龄飞行能力最强,其24 h平均飞行时间、平均飞行距离和平均飞行速率分别达到12.16±0.74 h、48.94±3.40 km和3.76±0.12 km/h。雌蛾与雄蛾间的各项飞行参数均无显著差异,但处女成虫平均飞行距离和平均飞行速率均显著高于已交配个体。对渤海湾野外迁飞种群飞行能力的测定显示,早季节北迁个体和晚季节回迁个体的平均飞行时间和平均飞行距离无显著差异,但皆显著低于实验室种群。黄地老虎具有较强的飞行能力,日龄和交配是影响其飞行能力的关键因素。     

Factors influencing flight potential of Choristoneura conflictana

Abstract Factors affecting the flight potential of Choristoneura conflictana, an insect that undergoes cyclical changes in population density, are investigated using computer‐linked flight mills. Female and male moths are flown for a 12‐h period and the longest single flight and total flight distance of each moth is recorded. After flight bioassays, moths are subjected to lipid extraction with a soxhlet apparatus to determine the effect of body lipid content on flight. Larger C. conflictana moths fly farther than smaller moths. Female C. conflictana fly farther than male moths but the effects of both mating status and moth age on the distance flown are dependent on sex. Mated females fly farther than virgins and older females fly farther than young females but these relationships do not occur in males. Body lipid content affects the distance flown by both females and males through a significant interaction with sex and age. The factors examined in this study will vary with density in natural populations and are predicted to be important indicators of flight potential and dispersal in this species.     

The odour makes the difference: male moths attracted by sex pheromones ignore the threat by predatory bats

How animals adjust their foraging or mate finding behaviour according to the risk of predation has received much attention recently. However, few studies have focused on the behaviour of prey when stimuli representing different adaptive behaviours originate from different sensory modalities. Here we present data on how male moths trade off odour-mediated mate attraction and auditory-mediated predator avoidance depending on the relative quality of the mate signal. Males of Agrotis segetum (Noctuidae) and Plodia interpunctella (Pyralidae), orienting towards a sex pheromone source in a flight tunnel, were exposed to ultrasound mimicking the echolocation calls of a bat, i.e. high predation risk. Males of both species accepted the predation risk when attracted to pheromone sources of high quality (female gland extract or complete synthetic blend at high dose), manifested in similar percentages reaching the pheromone source in moths with and without ultrasound exposure. In contrast, a lower proportion of ultrasound-exposed males than unexposed ones located the pheromone source when moths were flying towards pheromone sources of low quality (incomplete synthetic blend or complete synthetic blend at low dose), due to more time invested in defence manoeuvres. Furthermore, the risk taking behaviours of these moth species seem to be similar in spite of the fact that their ultrasonic hearing systems have evolved independently.     

Effects of sex pheromone in electrostatic powder on mating behaviour by Lobesia botrana males

Abstract:  In laboratory trials, mating behaviour of males of Lobesia botrana Den. and Schiff. (Lep., Tortricidae) was investigated after treatment with an electrostatically chargeable powder, Entostat^TM. Male moths were powdered with either blank Entostat or Entostat containing sex pheromone. Significantly more Entostat adhered to L. botrana males when sex pheromone was added to the powder compared with blank Entostat. Powdering male moths with Entostat, with or without sex pheromone, caused a significant reduction in antennal response when antennae were placed 2 cm away in downwind direction, while there was little effect when antennae were placed 25–100 cm from the EAG in downwind direction. In a flight study, powdering males of L. botrana caused significant increase in time before flight initiation and reduction in proportion of males making contact with calling females compared with untreated males. In a mating experiment in Petri dishes (to minimize required search time to locate female), significantly fewer females mated successfully (based on dissection of bursa copulatrix) when males had been treated with pheromone-loaded powder. Overall, powdering males of L. botrana caused considerable suppression of mating behaviour on various levels, and these suppressing effects were increased after adding sex pheromone to Entostat.     

Observations on the orientation of tsetse flies (Glossina pallidipes) to wind-borne odours

ABSTRACT. Observations of the upwind flight of Glossina pallidipes Austen near a source of host odour show that in the absence of a visual target the insects tend to overshoot the odour source in fast, low flight. There is no sign of the crosswind 'casting' flight which characterizes the behaviour of moths under similar circumstances, except that a 180 turn is executed to bring the tsetse flies back to the vicinity of the odour source in downwind flight. This may be followed by a second overshoot and another 180 turn before the insects alight within a metre or so of the source. The results indicate that the orientation of tsetse flies to host odour may involve a step-wise approach to the odour source, providing an opportunity for assessment of wind direction when the insects are at rest between successive bursts of flight.     

Flight manoeuvers used by a parasitic wasp to locate host-infested plant

Cotesia rubecula Marshall (Hymenoptera: Braconidae) is a specialist larval parasitoid of the butterfly Pieris rapae L. which itself feeds almost exclusively upon cruciferous plants. Female wasps are attracted to the odour of host-infested plant (plant-host complex: PHC) and the probability of flights in a wind tunnel depends on females' prior oviposition experience with the PHC and on the concentration of the PHC odour. This study considers the effect of both factors on characteristics of oriented flight upwind towards the PHC. The flight track parameters that we measured and calculated were not significantly affected by these factors. C. rubecula females exhibited high average flight velocity and relatively straight flight tracks. There was a considerable variability between individuals, however, in their odour-modulated upwind flight tracks. Some females generated a zigzagging upwind flight track similar to those commonly observed from male moths responding to female sex pheromone. Other females flew along a straight track directly upwind. The flight tracks of most female wasps were intermediate between these extremes. The full range of these flight performances was observed to all experimental treatments.     

粘虫迁出与迁入种群的行为和生理特性比较

系统比较了田间粘虫Mythimnaseparata (Walker)迁出与迁入种群在飞行能力、 飞行肌干重、卵巢发育、交配以及保幼激素滴度等指标的差异。结果显示,迁出种群的飞行潜 力显著强于迁入种群,雌蛾中胸背纵肌平均干重（6.53 mg）也显著高于迁入种群（5.92 mg ）,但卵巢发育程度显著低于迁入种群;迁出种群的交配率和平均交配次数均显著低于迁入种 群;早期迁入的雌蛾卵巢发育级别和交配率相对较低,并随迁入时间的延长而增加。迁出与迁入 种群雌蛾的保幼激素滴度也存在显著差异,两者的JHⅡ滴度平均分别为4.63 ng/mg和8.69 ng/mg。这些结果说明,粘虫迁飞前后的行为、生理和生殖特性具有明显的变化,迁出种群具有较强的飞行潜力,生殖系统的发育受到暂时性抑制;而迁入种群飞行能力下降,卵巢发育级别 较高,交配率增加。同一世代早期迁入的雌蛾卵巢发育程度较低,表明粘虫迁飞是发生在成虫 发育的初期,迁飞过程中卵巢发育受到暂时性抑制,迁入以后便迅速发育并开始繁殖。粘虫迁 飞的行为和生理特性与“卵子发生 飞行拮抗综合症候(oogenesisi flight syndrome)”相符 。内分泌激素（保幼激素）在其迁飞与生殖的转换过程中起着重要的调控作用。     

Sex roles in the ghost moth Hepialus humuli (L.) and a review of mating in the Hepialidae (Lepidoptera)

Recently it has been found that female Lepidoptera belonging to diverse families actively court their males, rather than play a merely passive role. Male and female Hepialus humuli have been reported to come together in three different ways: (1) females are attracted to groups or ‘leks’ of white, hovering males by visual stimuli; (2) females are attracted to the males by olfactory-substances produced on the hind-tibial brushes of the males; (3) males are attracted to sedentary females by olfactory stimuli. During my study I observed H. humili males flying on a total of 21 nights in two different parts of England. The males hovered in groups for about 20 min each evening, starting and stopping their flights in synchrony. Timing depended on light intensity, northern moths flying later in the summer evenings than southern moths. I observed a total of 18 matings. Normally, a female from outside a male lek flew into the group and up to one of the males. This male then usually followed her to a settling position, where mating took place. In a few cases females touched males; in one case a female struck a male in the air so that both fell to the ground and were copulating when examined. Photographs of hovering males show that their hind tibial brushes are fully everted in flight. The organs are folded against the body when the moth is mating, at rest or dead. Whilst hovering, the males are apparently emitting pheromones which function as primary attractants, rather than as the aphrodisiacs of many other lepidopteran males. The mating behaviour of hepialids is reviewed. It is concluded that all studied hepialids which have male brush organs (some Hepialus and Oncopera, Sthenopis, Zenophassus) exhibit similar flight and mating behaviour: males hover, sit or loop back and forth on the spot in leks; females fly into male aggregations and mate there (although some published observations suggest otherwise). In contrast, hepialids such as Fraus, Oxycanus and other Hepialus that lack male brush organs have mating behaviour in which the males are the active partner, a more standard lepidopteran method. In view of the controversies surrounding mating in hepialids, future systematic and behavioural work on Hepialidae throughout the world will be worthwhile.