Diel Rhythmicity of Certain Life Events of a Ladybird, Propylea dissecta (Mulsant)

The diel rhythms of certain life events, viz. mating, oviposition, hatching, moulting, pupation and eclosion were investigated in ladybird, Propylea dissecta. The peaks of activity and major portions of all life events were recorded in the scotophase. Mating, oviposition and hatching rhythms did not change with days and were thus probably endogenous in nature. The predominant occurrence of life events in the scotophase is probably owing to the foraging rhythms, which occur in the photophase as evinced by literature.     

韭菜迟眼蕈蚊成虫行为活动昼夜节律

【目的】本研究旨在明确韭菜迟眼蕈蚊Bradysia cellarum成虫行为活动的昼夜节律,为其室内饲养、行为学研究和研发精准、高效的监测与防控新技术提供依据。【方法】室内系统观察记录了韭菜迟眼蕈蚊成虫羽化盛期求偶、交配、产卵、移动与静息等行为的昼夜节律,分析了其特定行为的时间分配特征。【结果】韭菜迟眼蕈蚊成虫的运动行为和静息行为白天和黑夜均有发生,夜间的繁殖行为(求偶、交配和产卵)频次高于白天的,各时间点的移动、静息和繁殖行为频次占比间均具有显著性差异。韭菜迟眼蕈蚊雌雄成虫的求偶节律相同,一天中求偶有两次高峰,分别出现在3:00和7:00。韭菜迟眼蕈蚊雌雄成虫的交配节律与雌成虫的产卵节律相似,雄成虫移动行为频次占比的峰值时刻均出现在3:00时,雌成虫移动行为频次占比的峰值时刻则出现在19:00时。雌雄成虫静息行为的频次占比均无明显昼夜节律高峰。在日时间分配上,雌、雄成虫以静息行为的时间占比最多,分别为89.53%和89.90%;求偶行为的时间占比最少,分别为0.56%和0.89%。雌雄成虫各行为的日时间占比差异不显著。【结论】韭菜迟眼蕈蚊成虫的求偶、交配、产卵、移动和静息行为具有明显...     

柳毒蛾繁殖生物学的初步观察

【目的】为了明确柳毒蛾Leucoma salicis(Linnaeus)交配的日节律高峰,温度和不同交配持续时间处理对成虫寿命、产卵量和孵化率等繁殖生物学的影响。【方法】将新羽化的柳毒蛾成虫置于养虫笼中,观察交配的日节律高峰,并统计不同温度和不同交配持续时间处理下的成虫寿命、产卵量和孵化率。【结果】成虫在羽化当晚的后半夜凌晨开始交尾,次日晚上开始产卵。成虫交配集中在羽化翌日凌晨3:00—5:00之间,高峰为4:00。产卵高峰都出现在2日龄成虫,但是,25℃下成虫交配持续时间(9.2 h)显著短于28℃(11.8 h)。交配持续时间为30、60和300 min的处理,雌成虫平均寿命显著长于对照(对照9.2 h),雄虫仅60 min的处理显著长于对照。同时,极短的交配持续时间(30 min)显著降低雌虫的产卵量和孵化率。【结论】试验明确了成虫交配的日节律高峰,在适宜的温度范围内(25~28℃),雌雄成虫的寿命、单雌总产卵量无显著差异,交配持续时间明显影响成虫寿命、产卵量和卵孵化率。     

Rhythmicity in life events of an aphidophagous ladybird beetle, Cheilomenes sexmaculata

Abstract:  The present laboratory experiments have been carried out to investigate rhythms in various life events, viz. mating, oviposition, hatching, moulting, pupation and eclosion, of an aphidophagous ladybird beetle, Cheilomenes sexmaculata under laboratory conditions. Incidences of mating and eclosion occurred mostly (66% and 73% respectively) in photophase. While oviposition, hatching, moulting and pupation occurred during scotophase with the peaks of the former two distributed between time intervals 12:00–15:00 h and 21:00–00:00 h respectively. Confinement of life events that are associated with vulnerable stages in scotophase might be an adaptation to prevent their exposure to natural enemies.     

Mating behaviour in Oncopeltus fasciatus: circadian rhythms of coupling, copulation duration and 'rocking' behaviour

ABSTRACT. Circadian rhythms are demonstrated in initiation and duration of copulation, and in 'rocking' by females during mating in the large milkweed bug, Oncopeltus fasciatus. In constant light or darkness there were no more than two or three recognizable cycles of any of these rhythms. In addition, light directly stimulated copulatory attempts, but did not influence their chance of success. Copulations were generally shorter during the early-mid photophase and longer during the late photophase in LD 16:8, while initiations of copulation were fewest during the scotophase. The males were mainly responsible for these rhythms. It is suggested that the diurnal rhythm in copulation duration probably evolved as a consequence of the rhythms of flight activity and/or oviposition. Sperm from the late photophase matings typically displaced 90–100% of sperm from prior matings, while sperm from the shorter early photophase matings typically displaced less prior sperm. Peak rocking activity during mating occurred from 6 to 8 h after lights-on in LD 16:8. Little rocking occurred during the late photophase, when the greatest percent of pairs are in copula. Feeding and drinking inhibited rocking activity, but the feeding rhythm did not drive the rocking rhythm. Rocking appears not to function in promoting termination of mating, positioning of the aedeagus, nor to mediate mechanical stimulation of egg production. Its function remains unknown.     

Male parental care and its adaptive significance in a neotropical frog

In the Puerto Rican frog Eleutherodactylus coqui, parental care is performed exclusively by males, and consists of attending the eggs and hatchlings at a terrestrial oviposition site. The two major behavioural components of parental care are egg brooding and nest defence against conspecific egg cannibals. Defence behaviour includes aggressive calling, biting, sustained biting, wrestling, and blocking directed against nest intruders. Parental care lasts from oviposition to hatching (17–26 days) and often for several days after hatching. During pre-hatching development, males are present in their nests 97.4% of the time during the day and 75.8% of the time at night. A large portion of this time is spent brooding eggs. In a field experiment, males were removed from their nests and the fate of clutches was monitored. Compared to control clutches (males not removed), experimental clutches had significantly lower hatching success and suffered significantly greater mortality from desiccation and cannibalism. Hence, parental care yields significant benefits to male fitness via increased offspring survival.     

Time, love and species

Physiological and behavioral phenomena of many animals are restricted to certain times of the day. Many organisms show daily rhythms in their mating. The daily fluctuation in mating activity of a few insects is controlled by an endogenous clock. The fruitfly, Drosophila, is the most suitable material to characterize the genetic basis of circadian rhythms of mating because some mutants with defective core oscillator mechanism, feedback loops, have been isolated. D. melanogaster wild-type display a robust circadian rhythm in the mating activity, and the rhythms are abolished in period or timeless null mutant flies (per(01) and tim(01)), the rhythms are generated by females but not males. Disconnected (disco) mutants which have a severe defect in the optic lobe and are missing lateral neurons show arrhythmicity in mating activities. Thus, the lateral neurons seem to be essential for the circadian rhythm in mating activity of Drosophila. Furthermore, an anti-phasic relation in circadian rhythms of the mating activity was detected between D. melanogaster and their sibling species D. simulans. The Queensland fruit flies or wild gypsy moth also show species-specific mating rhythm, suggesting that species-specific circadian rhythms in mating activity of insect appear to cause a reproductive isolation.     

Circadian clock controlling egg hatching in the cricket (Gryllus bimaculatus)

Adult crickets (Gryllus bimaculatus) were maintained under a 12-h light:12-h dark cycle (LD 12:12). After oviposition, their eggs were incubated under different lighting regimens at 23 degrees C, and temporal profiles of egg hatching were examined. When the eggs were incubated in LD 12:12 or in DL 12:12 with a phase difference of 12h from LD 12:12, throughout embryogenesis, 88% to 97% of hatching occurred within 3 h of the dark-light transition on days 17 and 18 of embryogenesis; the phases of the egg-hatching rhythms in the LD 12:12 and DL 12:12 groups differed by about 12 h. In eggs incubated in constant darkness (DD) throughout embryogenesis, a circadian (about 24 h) rhythm of hatching was found, and the phase of the rhythm was similar to that seen in eggs incubated in LD 12:12, but not DL 12:12, throughout embryogenesis. When eggs that had been incubated in DD after oviposition were transferred to DL 12:12 in the middle or later stages of embryogenesis and were returned to DD after three cycles of DL 12:12, the rhythm of hatching synchronized (entrained) to DL 12:12. However, when eggs in the earlier stages of embryogenesis were transferred from DD to DL 12:12 and returned to DD after three cycles, 52% to 94% of hatching did not entrain to DL 12:12. To determine whether photoperiodic conditions to which the parents had been exposed influenced the timing of egg hatching, adult crickets were maintained in DL 12:12, and their eggs were incubated in LD 12:12, DL 12:12, or DD throughout embryogenesis. The egg-hatching rhythm was also found in the eggs incubated under these three lighting regimens. In DD, the phase of the rhythm was similar to that seen in eggs incubated in DL 12:12, not LD 12:12, throughout embryogenesis. The results indicate that in the cricket, the timing of egg hatching is under circadian control and that the circadian rhythm of hatching entrains to 24-h light:dark cycles, but only if the light:dark cycles are imposed midway through embryogenesis. Therefore, by midembryogenesis, a circadian clock has been formed in the cricket, and this is entrainable to light:dark cycles. In addition, the photoperiodic conditions to which the parents (probably the mothers) have been exposed influence the timing of hatching, suggesting that maternal factors may regulate the timing of egg hatching.     

Circadian Reproductive Rhythms, Pair-Bonding, and Evidence for Sex-Specific Pheromones in Nadezhdiella cantori (Coleoptera: Cerambycidae)

Mating and oviposition rhythms and evidence for sex-specific pheromones of the gray-black citrus longicorn beetle Nadezhdiella cantori were investigated. The reproductive and flight activities of this insect mainly occurred between 1700 and 2400 h, and each activity had two peaks with the first one taking place within the 3 h before sunset (2100 h) and the second occurring within the 3 h after sunset. Circadian rhythms of mating and oviposition were significantly correlated but neither mating nor oviposition was significantly correlated with flight. It is suggested that mating and oviposition repeat in turn during pair-bonding and that flight is an indication of termination of reproductive activities in some individuals of a population. Males differentiated between sexes by touching. Mating behavior of males was stimulated by a contact female sex pheromone on the female body surface. Fighting behavior of males was mediated by a chemical on the male body surface. Females left trails of the contact sex pheromone on the trees when walking, which males used to locate them. Implications of these findings are discussed.     

Novel Fraction Collector for Studying the Oviposition Rhythm in the Turnip Moth

Turnip moths, Agrotis segetum (Schiff.) (Lepidoptera: Noctuidae), were held in a transparent plastic box with a window opening to a rotating paper drum upon which the females could lay eggs. A novel fraction collector, consisting of a standard 24-hr wall timer and simple electronic circuit, served to rotate the paper in hourly increments. The entire apparatus was housed in an environmental chamber on a 16 hr light: 8 hr dark photoperiod at constant 23.7°C and 55% r.h. Under these conditions a circadian rhythm of egg laying was indicated with a mean activity time 0.2 hr before dark and standard deviation of 2.1 hr. The relative egg productions during the second to seventh day of oviposition peaked on the third day. Differences in the circadian rhythms of mating and oviposition are considered in terms of ecological fitness.     

中华蛸繁殖行为

为了解中华峭(Octopus sinensis)繁殖行为特征,通过肉眼观察及水下摄像对其行为进行研究.结果 表明,中华蛸在繁殖期有运动、捕食、求偶、交配、产卵和护卵行为.中华蛸运动依靠漏斗喷水的反作用力进行游泳和爬行;以突然袭击的方式捕食日本蟳(Charybdis japonica),繁殖后期不再进食;中华蛸具明显的求...     

Circadian rhythms of locomotor activity in cockroach nymphs: free running and entrainment

The temporal organization of locomotor activity was investigated in nymphs of the cockroach Leucophaea maderae. Approximately 40% of the animals examined between 1 and 50 days of age exhibited a circadian activity rhythm in constant darkness (n = 172) with an average free-running period of 23.7 +/- 0.68 hr. Twelve of 17 animals in which activity was recorded for most or all of the final instar also exhibited periods of rhythmic activity. The rhythms of the nymphs could be entrained by light-dark (LD) cycles with periods of 22, 24, or 26 hr. In contrast, neither maternal influences during embryogenesis nor hatching from the egg was effective in synchronizing the rhythms. Although adult cockroaches can be readily entrained by temperature cycles, in nymphs temperature appeared at best to be a weak zeitgeber. Embryonic exposure to an LD cycle until 6 days prior to egg hatch was effective in synchronizing the activity rhythms of the nymphs, indicating that differentiation of an entrainable pacemaking system occurs prior to hatching.     

Juvenile hormone in earwigs: Roles in oogenesis,mating, and maternal behaviors

The role of juvenile hormone (JH) in courtship, mating, maternal behavior, and the ovarian cycle was studied in the ring-legged earwig, Euborellia annulipes (Lucas). The single, median corpus allatum makes and secretes JH III. JH III production was low in newly eclosed adult females, increasing as oocytes developed, maximal at about the time of oviposition, and low again in brooding females. Application of 35 or 122 μg JH III to newly eclosed females hastened the onset of courtship behavior, but had no effect on the age at which females first mated nor on the duration of mating, though the trend is toward advanced onset. Hormone treatment advanced the age of first oviposition and reduced clutch size and the proportion of eggs hatching but did not affect the interval from oviposition of the first clutch to oviposition of the second clutch, nor the size and proportion hatching of the second clutch. Acetone treatment and treatment with 6 μg JH III did not affect these parameters. Application of 50 μg JH III to females on the day of oviposition shortened the duration of maternal care and advanced the onset of the second gonadotropic cycle, compared with that of acetone-treated and precocene II-treated females. The duration of maternal care was positively correlated with the proportion of eggs hatching. JH titer analysis confirmed JH III to be the predominant hormone in this species and clearly demonstrated the absence of other homologues. This work also confirmed our hypothesis that intermediate to high levels of JH are associated with oocyte growth, mating, and cessation of maternal care; low levels of JH are associated with the period of maternal behavior and slow ovarian development. We are currently investigating factors which might regulate corpus allatum activity during the reproductive cycle and the subsequent period of maternal care. Arch. Insect Biochem. Physiol. 35:427–442, 1997. © 1997 Wiley-Liss, Inc.     

Daily rhythms in the sorghum shootfly, Atherigona soccata: oviposition, egg-hatch and adult eclosion

ABSTRACT. Daily rhythms controlling oviposition, egg-hatching and adult eclosion in the sorghum shootfly, Atherigona soccata Rondani, were investigated. Eggs were laid only during the photophase of a LD 12:12 cycle, in two peaks. Under continuous light, this oviposition was considerably attenuated but not made immediately arrhythmic. Egg-hatching and adult eclosion both commenced just before dawn. Some feature of the scotophase during or immediately after black-head formation apparently acts as a signal for hatching. Eclosion was controlled by light but its timing in the field was modified by temperature. The last 2–3 days of the pupal period constituted the most sensitive stage, and light signals received during this period determined the time of eclosion. Ecological advantages of these rhythms to the shootfly are discussed.     

Does lighting manipulation during incubation affect hatching rhythms and early development of sole?

Light plays a key role in the development of biological rhythms in fish. Previous research on Senegal sole has revealed that both spawning rhythms and larval development are strongly influenced by lighting conditions. However, hatching rhythms and the effect of light during incubation are as yet unexplored. Therefore, the aim of this study was to investigate the impact of the light spectrum and photoperiod on Solea senegalensis eggs and larvae until day 7 post hatching (dph). To this end, eggs were collected immediately after spawning during the night and exposed to continuous light (LL), continuous darkness (DD), or light-dark (LD) 12L:12D cycles of white light (LD(W)), blue light (LD(B); λ(peak)?=?463?nm), or red light (LD(R); λ(peak)?=?685?nm). Eggs exposed to LD(B) had the highest hatching rate (94.5%?±?1.9%), whereas LD(R) and DD showed the lowest hatching rate (54.4%?±?3.9% and 48.4%?±?4.2%, respectively). Under LD conditions, the hatching rhythm peaked by the end of the dark phase, but was advanced in LD(B) (zeitgeber time 8 [ZT8]; ZT0 representing the onset of darkness) in relation to LD(W) and LD(R) (ZT11). Under DD conditions, the same rhythm persisted, although with lower amplitude, whereas under LL the hatching rhythm split into two peaks (ZT8 and ZT13). From dph 4 onwards, larvae under LD(B) showed the best growth and quickest development (advanced eye pigmentation, mouth opening, and pectoral fins), whereas larvae under LD(R) and DD had the poorest performance. These results reveal that developmental rhythms at the egg stage are tightly controlled by light characteristics, underlining the importance of reproducing their natural underwater photoenvironment (LD cycles of blue wavelengths) during incubation and early larvae development of fish.     

Timing of oviposition and reproductive skew in cobreeding female burying beetles (Nicrophorus vespilloides)

Burying beetles (genus Nicrophorus) are known for their elaborate parental care. Two or more conspecific females may reproduceon the same carcass, especially when the carcass is large.Here we present the results of experiments in which we observedpatterns of larval hatching and parental care in unmanipulatedcobreeders, manipulated hatching synchrony between cobreeders,and compared patterns of oviposition in cobreeding and single females. Our results show that in these cobreeding associations,one of the females may or may not monopolize the carcass duringthe period of larval hatching. We present evidence that ineither case, infanticide based on temporal cues constitutesan important proximate mechanism underlying the observed reductionin average reproductive success in cobreeding females. Femaleswith higher synchrony (i.e., greater overlap between their oviposition patterns) produce larger broods with lower reproductive skew.Cobreeding females oviposit later and less synchronously thansingle breeders. Such delayed oviposition may reduce the riskthat a female's larvae fall victim to cannibalistic acts committedby her cobreeder or maximize her own opportunity to selectivelykill her cobreeder's larvae.     

基于自动录音技术研究三种雉类鸣叫特征和节律

自动录音机是一种低成本、高效、可以在较长时间和较大空间范围内对物种的活动进行有效监测的设备。2019年4至6月,在北京小龙门地区(40°00′N,115°26′E)褐马鸡(Crossoptilon mantchuricum)、勺鸡(Pucrasia macrolopha)和环颈雉(Phasianus colchicus)的栖息地内布设了songmeter自动录音机,对三种雉类的鸣声进行为期2个月的连续收集。利用Kaleidoscope软件(Wildlife Acoustics公司,美国),对不同雉类鸣声进行了人工辅助的机器学习和自动识别,从录制的22 536 h录音数据中提取了褐马鸡、勺鸡和环颈雉的鸣声。优化鸣声提取的时频参数后,勺鸡鸣声提取的正确率为73.32%,探测率为52.91%;环颈雉鸣声提取的正确率为89.32%,探测率为67.36%;褐马鸡鸣声提取的正确率较低,仅为8.69%,探测率为58.54%。结合三种雉类的繁殖资料,揭示了三种雉类的鸣声节律:褐马鸡和环颈雉有早晚两个鸣叫高峰期,但高峰时段不尽相同,勺鸡只存在鸣叫早高峰;褐马鸡、勺鸡和环颈雉在交配期、孵卵前期具有一个鸣叫...     

Effects of multiple mating on the fecundity of an invasive pest (Octodonta nipae): the existence of an intermediate optimal female mating rate

Multiple mating is found in many insect taxa where both of the sexes can mate more than once. For males, this leads to the advantage of increasing their paternity by fertilizing more females. However, there is a trade‐off of resource allocation between reproduction and other life‐history characters. In the present study, the impact of increased mating rate on reproductive fitness of the invasive nipa palm hispid beetle Octodonta nipae Maulik (Coleoptera: Chrysomelidae) is investigated. A series of mating frequencies (i.e. 1, 5, 10, 15, 20 times) is selected from video frame playback, ranking from the minimum to maximum mating rate observed under laboratory conditions over a given time period. Fecundity parameters such as lifetime egg production, egg‐hatching rate, effective oviposition period and longevity are investigated for the evaluation of reproductive efficiency. For female O. nipae, increased fecundity is correlated with the mating frequency. Females mating 15 times lay the largest number of eggs (138.82 ± 6.87) and have a hatching rate of 47.43 ± 4.08%. After mating 20 times, females suffer significant declines in oviposition (90.31 ± 8.38 eggs) and egg‐hatching rate (34.16 ± 4.93%). Moreover, the population growth rate reaches a maximum in the females that mate 15 times. The results show that multiple matings in O. nipae have an intermediate optimal range within which female reproductive success is enhanced, providing empirical evidence for the existence of a trade‐off between costs and benefits during copulation based on resource allocation.     

Scheduled daily mating induces circadian anticipatory activity rhythms in the male rat

Daily schedules of limited access to food, palatable high calorie snacks, water and salt can induce circadian rhythms of anticipatory locomotor activity in rats and mice. All of these stimuli are rewarding, but whether anticipation can be induced by neural correlates of reward independent of metabolic perturbations associated with manipulations of food and hydration is unclear. Three experiments were conducted to determine whether mating, a non-ingestive behavior that is potently rewarding, can induce circadian anticipatory activity rhythms in male rats provided scheduled daily access to steroid-primed estrous female rats. In Experiment 1, rats anticipated access to estrous females in the mid-light period, but also exhibited post-coital eating and running. In Experiment 2, post-coital eating and running were prevented and only a minority of rats exhibited anticipation. Rats allowed to see and smell estrous females showed no anticipation. In both experiments, all rats exhibited sustained behavioral arousal and multiple mounts and intromissions during every session, but ejaculated only every 2-3 days. In Experiment 3, the rats were given more time with individual females, late at night for 28 days, and then in the midday for 28 days. Ejaculation rates increased and anticipation was robust to night sessions and significant although weaker to day sessions. The anticipation rhythm persisted during 3 days of constant dark without mating. During anticipation of nocturnal mating, the rats exhibited a significant preference for a tube to the mating cage over a tube to a locked cage with mating cage litter. This apparent place preference was absent during anticipation of midday mating, which may reflect a daily rhythm of sexual reward. The results establish mating as a reward stimulus capable of inducing circadian rhythms of anticipatory behavior in the male rat, and reveal a critical role for ejaculation, a modulatory role for time of day, and a potential confound role for uncontrolled food intake.     

Polyandrous females acquire indirect benefits in a nuptial feeding species

The relative force of direct and indirect selection underlying the evolution of polyandry is contentious. When females acquire direct benefits during mating, indirect benefits are often considered negligible. Although direct benefits are likely to play a prominent role in the evolution of polyandry, post‐mating selection for indirect benefits may subsequently evolve. We examined whether polyandrous females acquire indirect benefits and quantified direct and indirect effects of multiple mating on female fitness in a nuptial gift‐giving spider (Pisaura mirabilis). In this system, the food item donated by males during mating predicts direct benefits of polyandry. We compared fecundity, fertility and survival of singly mated females to that of females mated three times with the same (monogamy) or different (polyandry) males in a two‐factorial design where females were kept under high and low feeding conditions. Greater access to nutrients and sperm had surprisingly little positive effect on fitness, apart from shortening the time until oviposition. In contrast, polyandry increased female reproductive success by increasing the probability of oviposition, and egg hatching success indicating that indirect benefits arise from mating with several different mating partners rather than resources transferred by males. The evolution of polyandry in a male‐resource‐based mating system may result from exploitation of the female foraging motivation and that indirect genetic benefits are subsequently derived resulting from co‐evolutionary post‐mating processes to gain a reproductive advantage or to counter costs of mating. Importantly, indirect benefits may represent an additional explanation for the maintenance of polyandry.