Onset Of Reproductive Activity Research Articles

Behaviour of the population structure and performance indicators in sheep production systems in Colombia

Objective. The behavior of the population structure, indicators of reproduction and production in sheep were determined. Materials and methods. 104 sheep farms were monitored, in 7 regions of Colombia, corresponding to a population of 7708 animals, distributed in: Inventory, Infants, Growth 1, Development, Completion and Adults. It was applied descriptive statistics and simple ANOVA and with covariance. Results. The mean Inventory per farm is 74.1±79 heads; category Infants corresponds to 8.7% of the population, Growth1 15.3%, Development 12%, Completion 20.8% and Adults 43.3%. The Age of Conception in Corderas was 15.7±5.5 months; Age at First Delivery of 20.7±5.5 months; the Birth Interval Concepción was 160.3±65.4 days, the Interval Between Births was 310.3±65.4 days. The Birth Weight of males was 4.2±4 kg and females 3.4±1.2 kg, without significant differences (p>0.05); Weaning Weight, adjusted at 90 days (3 months) in males was 16.8±6.4 kg and females 16.3±5.6 kg, without significant differences (p>0.05); the weight at 12 months for males was 34.9±13.7 kg and females 33.4±10.7 kg, without significant differences (p>0.05). Discussion. Different sizes of farms are evident; the onset of reproductive activity is late, with Interval Between Births that maintain a not very dynamic reproductive rhythm. The productive variables are within the range. Conclusions. The indicators obtained represent referential information on the population structure and productive behavior of sheep production systems in the seven monitored regions of Colombia.

Soft coral reproductive phenology along a depth gradient: Can "going deeper" provide a viable refuge?

Many species across a wide range of taxa and habitats display phenological shifts and differences in response to both environmental gradients and climate change. Moreover, the wide‐scale decline of numerous ecosystems is leading to increasing efforts to identify zones that might serve as natural refuges from various disturbances, including ocean warming. One such refuge was suggested to be that of the deep coral reefs, but whether depth can provide coral populations with a viable and reproductive refuge remains unclear. Given the global coral‐reef degradation and the key role that corals play as ecosystem engineers, their reproductive ecology has been widely studied. A particular knowledge gap nonetheless exists regarding coral reproductive phenology along a depth gradient. Filling in this gap may uncover the environmental cues that regulate coral reproduction, leading to better predictions of population connectivity, and their possible responses to climate change and other environmental changes. Here, using long‐term in situ observations of the soft coral Rhytisma fulvum's reproductive activity along its entire depth range (0–45 m), we examined the relationship among several environmental factors and the coral's reproductive phenology and activity over five successive annual breeding seasons. Compared with the shallow depths, a lower number of reproducing colonies was found in habitats deeper than 30 m, highlighting possible constraints on coral reproduction at the deeper end of their range. Our results further revealed that an increase in seawater temperature over 1–2‐day intervals during the breeding season correlated with the onset of reproductive activity along the depth gradient, leading to different reproductive periodicities in different depths. These differences suggest that differential temperature regimes and reproductive timing across depth may create intraspecific temporal reproductive segregation, possibly reducing connectivity among populations along a depth gradient. Moreover, we found high variability among years in both the timing of breeding activities and in the level of reproductive synchrony among corals from different depths. Overall, our study questions whether depth can provide a long‐term and viable refuge for corals in the face of global environmental changes.

Age, Growth and Maturity of Red Porgy Pagrus pagrus (Sparidae) from Southeastern Brazil

Age, growth and length-at-maturity of the red porgy Pagrus pagrus were studied off the southeastern coast of Brazil. A total of 798 otoliths from specimens sampled from the hook-and-line commercial landings between January and December 2017 were used. Age and growth were estimated by counting and measuring increments in sectioned sagitta otoliths, and length-at-maturity was estimated based on macroscopic gonadal analysis. The annual periodicity of opaque zones was validated by marginal increment analysis. Growth curves were estimated by fitting von Bertalanffy growth model to the observed length-at-age data. A single annulus was laid down in summer, from November to February, associated with coastal upwelling of the subtropical South Atlantic Central Water (14.9–18.0°C) and with the onset of reproductive activity. The maximum age observed was 11 years in females and 12 years in males. The parameters of the von Bertalanffy model were: males (L∞ = 419.9 mm, k = 0.347 year−1, t0 = – 0.199), females (L∞ = 503.8 mm, k = 0.253 year−1, t0 = – 0.154) and sexes combined (L∞ = 461.0 mm, k = 0.290 year−1, t0 = – 0.260). The mean length and age at first maturity was estimated at 258 mm (2.5 years) for males and 274 mm (3.0 years) for females. For both sexes, maturity precedes size and age at which specimens are fully recruited to hook-and-line fisheries at age 4 (327 mm).

Average daily gain rates determine eye muscle area and rump fat depth of beef heifers

In cow-calf beef production systems, the growth and development of replacement heifers deserve special attention because they affect the age at puberty and the onset of reproductive activity. Therefore, the objective of this study was to test if changes in average daily gain (ADG) have an effect on eye muscle area, rump fat depth and back-fat thickness in developing beef heifers. These traits of 42 beef heifers were measured over time. The results of the current study allow inferring that heifers older than 385 days and with high rates of ADG (above 0.950 kg per day) have the greatest impact on longissimus muscle area growth (above 57 cm2). On the other hand, it is observed that younger heifers (less than 230 days old) do not exceed 48 cm2 of the longissimus muscle area, even with ADGs around 1.25 kg. A positive relationship between the rate of ADG and rump fat depth was also evidenced, observing that rump fat depth deposition is influenced by the rate of ADG. The results of the current study show a linear trajectory of rump fat depth, indicating that for every 0.10 kg of ADG during a period exceeding 56 days, an increase of 1.09 mm of rump fat depth occurs. In conclusion, this study illustrates a simple way on how ADG and age affect the body composition traits in beef heifers and shows that changes in average daily gain affect muscle and fat tissue growth, as determined by longissimus muscle area and rump fat depth in growing beef heifers.

Sexual precocity and productivity of beef cattle female under grazing conditions

In view of the importance of female reproductive traits as a key profit indicator in beef-cattle production systems, the objective of the present study was to explore the relationships between female sexual precocity and potential predictive traits of easy and early measurement, related to the productive and reproductive efficiency. Heifers born in 2011 and 2012 (n = 132) from five genetic groups (Angus, Hereford, Angus-Hereford, Hereford-Angus and Argentine Creole) in 2 years (Trial 1 and Trial 2) under grazing conditions were evaluated. After weaning, the presence of corpus luteum, liveweight, body condition score, hip height, rump fat thickness and rib fat thickness were recorded every 28 days, and Longissimus muscle area at 15 months of age. Also, to evaluate the relationships between age at puberty and the subsequent production efficiency, the annual records of 895 cows (217 Angus, 253 Hereford, 125 Creole, 116 Angus-Hereford and 184 Hereford-Angus) born between 1986 and 2009 were studied to estimate the average annual productivity of cows, and its components of (Co)variance, heritability and breeding values. Nutritional conditions immediately after weaning were determinants in reaching puberty. The univariate animal model for average annual productivity showed a heritability of 0.14 ± 0.05. Regression multiple and covariance analyses revealed that the rib fat thickness at 450 days of age was a good predictor of age at puberty, but lose some relevance as early selection criterion. Finally, it is important for future studies to analyse in more detail the existence of critical thresholds of fat deposition for the onset of reproductive activity.

Hormonal correlates of natal dispersal and rank attainment in wild male baboons

In many mammals, maturational milestones such as dispersal and the attainment of adult dominance rank mark stages in the onset of reproductive activity and depend on a coordinated set of hormonal and socio-behavioral changes. Studies that focus on the link between hormones and maturational milestones are uncommon in wild mammals because of the challenges of obtaining adequate sample sizes of maturing animals and of tracking the movements of dispersing animals. We examined two maturational milestones in wild male baboons—adult dominance rank attainment and natal dispersal—and measured their association with variation in glucocorticoids (fGC) and fecal testosterone (fT). We found that rank attainment is associated with an increase in fGC levels but not fT levels: males that have achieved any adult rank have higher fGC than males that have not yet attained an adult rank. This indicates that once males have attained an adult rank they experience greater energetic and/or psychosocial demands than they did prior to attaining this milestone, most likely because of the resulting participation in both agonistic and sexual behaviors that accompany rank attainment. In contrast, natal dispersal does not produce sustained increases in either fGC or fT levels, suggesting that individuals are either well adapted to face the challenges associated with dispersal or that the effects of dispersal on hormone levels are ephemeral for male baboons.

Leptin regulation of inward membrane currents, electrical activity and LH release in isolated bovine gonadotropes

Leptin, a peptide hormone produced by adipocytes, is recognized as one of the signals involved in the onset of reproductive activity. The leptin receptor has been found in hypothalamic neurons and pituitary gonadotropes, suggesting that the hormone may act at both sites to stimulate the secretion of GnRH and consequently, FSH and LH. In response to a stimulus such as a hypothalamic secretagogue, gonadotropes respond with changes in electrical activity, intracellular Ca2+ and hormone release. The main aim of this report was to investigate whether leptin promotes a change in the electrical and secretory activities of bovine gonadotropes. After 48 h of treatment with leptin (10 nM) significant changes in the action potential properties were observed in gonadotropes, which included an increase in amplitude, time-to-pike and post-hyperpolarization, as well as a decrease in firing threshold. Likewise, leptin induced a significant (∼1.3-fold) up-regulation of voltage-gated Na+ channel current density, and a selective increase (∼2.1-fold) in Ca2+ current density through high voltage-activated channels. Consistent with this, leptin enhanced GnRH-induced secretion of LH measured by ELISA. We suggest that leptin enhances membrane expression of voltage-gated Na+ and Ca2+ channels, which results in a modulation of the action potential properties and an increase in hormone release from gonadotropes.

Onset of reproductive activity of white and natural colored corriedale ewe lambs

The objective of this study was to estimate differences in growth, plasma progesterone (P4) and age at puberty between white and natural colored Corriedale ewe lambs. Thirty ewe lambs with average age of 12 months were randomly allocated to genetic groups: white (WC, n = 15) and natural colored (NC, n = 15). Ewes were maintained under extensive grazing conditions on natural pasture, and herbage mass was estimated over a 28-day experimental period. Morphometric measurements (front and hind height, body length, thoracic perimeter, rump length and width, wool fiber length), body condition score (CC) and weight were taken at 28-day intervals. There was no effect of genetic group on body weight, average daily gain and morphometric measurements (P > 0.05). The WC ewe lambs had longer fiber length (P 0.05); however, it increased above 1ng ml-1 in NC from January onward and in WC from March onwards. Estrus was detected at the same time in both groups. The results of this study indicate that both genetic groups have similar growth patterns and ovarian activities.

Seasonality and breeding success of captive and wild Tasmanian devils (Sarcophilus harrisii)

The synchrony and timing of reproductive events are crucially important factors to maximize individual and offspring survival, especially in seasonal environments. To increase our understanding of the physiological basis of seasonality and the influence of associated environmental factors (maximum temperature, day length and rate of day length change associated with different latitudes) on reproduction in Tasmanian devils, we reviewed records and research data from captive facilities throughout Australia in comparison to those from a wild population study (1974–1987). Overall, breeding activity began 2 weeks earlier in the captive than the wild population (week 5.7 ± 0.6 versus week 7.7 ± 0.5 for devils entering into estrus during the first two week phase; n = 24 and n = 23 respectively). If the timing of reproductive activity is considered against absolute day length rather than date, both the captive and wild populations displayed similar distributions (12.9 ± 0.7 h versus 13.0 ± 0.7 h respectively; P < 0.01) confirming day length as a proximal cue involved in eliciting a physiological response to trigger seasonal reproductive activity regardless of location. Wild devils had a higher breeding success (75%; n = 169 versus 43%; n = 115) and larger litter size (3.4 ± 0.9 versus 2.8 ± 1.1 joeys per litter) than captive devils (P < 0.05). Mean maximum temperature at the onset of reproductive activity (P < 0.05) was higher for the captive than the wild population (28.1 ± 4.0 °C versus 22.3 ± 2.7 °C respectively). The drivers for reproductive success in captive Tasmanian devils are likely multifactorial, but our results suggest that elevated temperatures associated with shifts in breeding activity and geographical location should be examined further.

Long-term experiments on lifespan, reproductive activity and timing of reproduction in the Arctic copepod Calanus hyperboreus

Several experiments were conducted with starved and fed females of the Arctic copepod Calanus hyperboreus (1) to investigate their lifespan, reproductive period, egg production and egg viability; (2) to study the effect of origin, i.e., Atlantic and Arctic Waters in the Greenland Sea, on the timing of reproduction; and (3) to study the effect of time of collection on the onset of reproductive activity as a first approach to study control mechanisms of the reproductive cycle. Females collected in October produced up to 1,000 eggs and had a maximum lifespan of 164 days without feeding, whereas fed females produced up to ca. 6,000 eggs and survived up to 806 days. These observations support earlier assumptions that females were multiannual-iteroparous, i.e., capable to spawn in successive years, which would be unique for calanoid copepods. In starved females, clutch size decreased significantly with each spawning event. Viable eggs were produced during most of the life time. There was no difference in the timing of reproductive activity between females from the West Spitsbergen Current and the Greenland Sea Gyre. Fed and starved females collected in May and June began to spawn circa 2 and 4 months after collection, respectively, whereas females collected in August and October started spawning at the same time, in the middle of October. This indicates initiation of reproductive activity in the field in August, coincident with the descent into deep waters. Potential cues for the untimely spawning of females collected in spring and ‘unnatural’ feeding in fall experiments are discussed. Their large size, robustness and combination of different types of diapause in their life cycle make C. hyperboreus a good model organism to study diapause control mechanisms.

The male effect stimulus positively increased the ovarian and reproductive seasonality in Criollo goats irrespective of a controlled photoperiodic regime

Present study evaluated the presence of a sexually active male buck upon the onset of reproductive activity and estrous cycle progression in Criollo goats exposed to a 6-month long controlled photoperiod in a range of 13.4–10.6 light-hours per day. Mexican-native (Criollo) goats (n=10) were randomly assigned into 2 groups: (1) goats exposed to a male buck (n=5); (2) goats not exposed to a male buck (n=5). Blood samples were taken weekly to quantify serum-progesterone levels through radioimmunoanalysis. Male exposure increased luteal activity and estrous cycle progression reflected as a higher number of days in luteal activity (44±9.05 vs. 32.3±20.6); a reduced number of days in anestrous (4.0±4.8 vs. 51.9±28) and a greater number of luteal phases (15.7±4.4 vs. 11.3±8.7) without compromising serum progesterone levels (6.8±0.8 vs. 7.3±0.5). In conclusion, presence of a sexually active male induced a greater ovarian activity in Criollo goats, shortening seasonal anestrous irrespective of the controlled photoperiodic regime.

Calcium and phosphorus values and their derivatives in captive tortoises (Testudo species)

To evaluate the relationships between total calcium and phosphorus and ionised calcium and phosphorus values in clinically healthy tortoises. Jugular blood samples were obtained from 25 tortoises, as part of a health screen of the population. These comprised Hermann's tortoises, Testudo hermanni boettgeri, spur-thighed tortoises, Testudo graeca ibera, marginated tortoises, Testudo marginata, and horsfield tortoises, Testudo horsfieldi. Plasma from these samples were analysed for total calcium, ionised calcium and phosphorus levels. These samples were taken in the immediate posthibernation period, before the onset of reproductive activity. Females exhibited statistically significantly higher levels of phosphorus. Ionised calcium and total calcium levels were elevated in females compared with males, but this was not statistically significant. Females did have statistically significantly higher calculated solubility indexes and statistically significantly lower ratios compared with males. This study has provided an insight into the ratios and solubility indexes in tortoises, and this information may lead to further understanding of the significance of these parameters in chelonians.

Ramelteon attenuates age‐associated hypertension and weight gain in spontaneously hypertensive rats

The neuroendocrine theory of aging suggests the common mechanisms of developmental (prereproductive) and aging (postreproductive) processes and identified a cluster of conditions (hypertension, obesity, dyslipidemia, type 2 diabetes, menopause, late onset depression, vascular cognitive impairment, impairment of immune defense, and some forms of cancer) as age-associated neuroendocrine disorders (AAND). Obesity, dyslipidemia, hypertension, and type 2 diabetes were later described as metabolic syndrome (MetS). Because melatonin attenuated development of MetS is age-dependent, that is, in young and old, but not in middle-aged rats, we studied the effect of the selective melatonin agonist, Ramelteon, on the two core symptoms of MetS/AAND: hypertension and body weight gain in spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto male rats (WKY). SHR rats developed hypertension at the time of maximal weight gain that coincided with the onset of reproductive activity (8-10 weeks old). Chronic (but not acute) administration of Ramelteon (in drinking water, 8 mg/kg/day, from 4 to 12 weeks of age) attenuated age-associated increase of systolic blood pressure (tail-cuff method) by 45%, and age-associated body weight gain by 30%. Acute and chronic Ramelteon did not affect blood pressure and body weight in normotensive WKY rats. Ramelteon-induced attenuation of age-associated hypertension and weight gain suggests that Ramelteon might attenuate the other symptoms of MetS/AAND and might be useful in the treatment of MetS/AAND during puberty, menopause, and old age.

Pheromonal predisposition to social parasitism in the honeybee Apis mellifera capensis

In honeybees, worker reproduction is mainly regulated by pheromones produced by the brood and the queen. The source of one of the queen pheromones influencing worker reproduction has been located in the mandibular glands. In nonlaying workers, this gland’s profile is dominated by fatty acids that are incorporated into the food given to the brood and to nest mates. After queen loss and onset of reproductive activity, workers are able to synthesize different fatty acids, which are normally only produced by queens and that contribute to their reproductive success. Apis mellifera capensis workers have the ability to rapidly produce queen-like mandibular profiles that could represent an important factor in their ability to behave as facultative intraspecific social parasites. Indeed, A. m. capensis workers can take over reproduction from the host queens in colonies of other subspecies. Here, we show that in the presence of their own queen, the mandibular gland profile of A. m. capensis workers is dominated by the precursor of the major compound of the queen pheromone. This is a unique trait among honeybee workers and suggests that A. m. capensis workers are primed for reproduction and that this phenomenon represents a pheromonal predisposition to social parasitism. We identified geographical variation in the ratio of queen- to worker-specific compounds in the mandibular gland profile of A. m. capensis workers, which corresponds with the introgression with the neighboring subspecies A. m. scutellata.

NUTRITION AND THE ONSET OF REPRODUCTIVE ACTIVITY

Nutrition and the Onset of Reproductive Activity Get access Nutrition Reviews, Volume 16, Issue 7, July 1958, Pages 209–210, https://doi.org/10.1111/j.1753-4887.1958.tb00762.x Published: 01 July 1958

Out-of-season breeding of Romney sheep using artificially induced long days

This experiment investigated the effects of subjecting Romney ewes to artificially induced long days (24 L : 0 D) in spring for 30 days, then abruptly applying 8 hours of darkness (16 L : 8 D) to induce the onset of reproductive activity. The treatment groups were: light + progesterone; light + progesterone + eCG; and progesterone + eCG (ambient photoperiod; control). Blood samples were collected over a 24-h period for analysis of serum melatonin concentrations. Ewes’ ovaries were examined laparoscopically 9 days after progesterone removal. Duration of secretion and maximal concentrations of melatonin were lower in ewes treated with light + progesterone (±eCG) compared with the control ewes. Fewer light + progesterone treated ewes displayed oestrus (66%) and were subsequently identified as being pregnant (28%) compared with ewes treated with light + progesterone + eCG (98% and 53%) and control ewes (97% and 65%, respectively). Conception rates were lower in light + progesterone treated ewes (43%) compared with light + progesterone + eCG (55%) and control ewes (67%). Results obtained indicate that artificially induced long days did not improve the results of out-of-season breeding program beyond that achieved with the use of eCG.

Growth and feed conversion of Boran ( Bos indicus) and Holstein×Boran heifers during three physiological states receiving different levels of a tropical diet

Forty-eight heifers of two genotypes, Boran ( Bos indicus) and Holstein×Boran, were allocated to three feeding levels equivalent to 1.0, 1.2 and 1.4 times calculated metabolisable energy requirements for maintenance (ME m). The experiment started at the onset of reproductive activity, when the Boran and crossbred heifers were 4.4 and 2.2 years old, respectively. The response to feeding level was investigated in three physiological states: (i) puberty and growth (87 days), (ii) work and growth (94 days, 51 days thereof with work), and (iii) pregnancy and recovery from work (115 days). Neither genotype nor feeding level had effects on nutrient digestibility, digesta passage rate and reproductive performance. Daily gains and feed conversion efficiency were higher in well-fed heifers ( P<0.001 and P<0.01). Estimated ME m was 0.54 MJ/kg metabolic weight ( W 0.75) in both genotypes during puberty and growth. Imposing work required additional 0.20 and 0.10 MJ ME/kg W 0.75 in Boran and crossbreds, respectively. Recovery from work, associated with early pregnancy, apparently reduced ME m to 0.30 MJ/kg W 0.75. This could be explained as a result of compensatory growth. The efficiency of utilisation of metabolisable energy for growth (0.28) did not differ ( P>0.1) between genotypes and physiological states.

Assessment of Stylosanthes seed yield reduction caused by phytoplasma-associated diseases

The effect of Stylosanthes little leaf disease on Stylosanthes scabra cv. Seca seed yield was monitored over 2 consecutive seasons at Southedge Research Station in northern Queensland. The time of initial symptom expression was recorded during weekly assessments to determine what effect time of infection after planting had on seed yield. First flowering date was recorded to establish whether the developmental stage of the plant, as indicated by the onset of reproductive activity, at the time of symptom expression influenced the effect of Stylosanthes little leaf disease on yield. At the end of each season, both diseased and asymptomatic plants were harvested and seed yield determined. Seed yield data from the 1999 season showed that there was no significant difference between the mean yield of symptomatic plants, regardless of when they first showed symptoms, and that of asymptomatic plants. However, during the 2000 season plants that showed symptoms early in the season had a significantly lower seed yield than both asymptomatic plants and plants that became diseased later in the season. This decrease in productivity amounted to a yield loss of 98.8 and 56.5% when the plants showed symptoms at 79�and 110 days, respectively, after planting. If plants became diseased within 30 days of first flowering, they did not produce significant amounts of seed. Yield remained low even when the time between first flowering and initial symptom expression increased up to 60 days, after which yield was extremely variable but within the range of that observed for individual asymptomatic plants. It is concluded that Stylosanthes little leaf disease has little or no effect on seed yield if plants have been flowering for about 8 weeks before symptom expression.

Overwintering strategies in Calanus finmarchicus

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 193:95-107 (2000) - doi:10.3354/meps193095 Overwintering strategies in Calanus finmarchicus Alasdair Hind1, William S. C. Gurney1,*, M. Heath2, A. D. Bryant2 1Department of Statistics and Modelling Science, University of Strathclyde, Glasgow G1 1XH, Scotland, UK 2Fisheries Research Services, Aberdeen Marine Laboratory, Aberdeen AB9 8DB, Scotland, UK *Corresponding author. E-mail: bill@stams.strath.ac.uk ABSTRACT: The marine copepod Calanus finmarchicus is known to overwinter at depth in a state analogous to diapause in terrestrial insects, but the cues which cause individuals to enter and leave this state are the subject of speculation. In this paper we use a simple demographic model, driven by environmental data from 4 distinct locations in the organism's eastern range, to test the plausibility of a number of candidate mechanisms. We start from Miller et al.'s (1991; Mar Ecol Progr Ser 72:79-91) hypothesis that diapause is controlled by photoperiod, and show that this leads to unrealistic patterns of reproductive activity in northern waters. We extend the model to include the recently reported phenomenon (Hirche 1996a; Ophelia 44:111-128) of delayed gonad maturation in females experiencing low food concentrations. This yields more plausible annual patterns, but fails to reproduce observed geographical variation in the timing of the yearly onset of reproductive activity. Our final model dispenses with photoperiodic control and assumes that diapause duration is controlled by the normal development processes operating at a reduced rate. This model reproduces all the qualitative features of the patterns of reproductive activity observed at our 4 test sites, thus demonstrating that photoperiod cueing is not a necessary prerequisite for the regular re-ascension of C. finmarchicus into surface waters. KEY WORDS: Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 193. Publication date: February 28, 2000 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 2000 Inter-Research.

Tethered-flight and Age-related Reproductive Performance of Helicoverpa punctigera (Wallengren) and H. armigera (Hubner) (Lepidoptera: Noctuidae)

Flight capacity of female and male moths was age dependent in both H. punctigera and H. armigera using a tethered-flight technique. In H. punctigera, flight capacity increased from the first night following emergence up to Night 4, and was maintained at least until Night 10. In H. armigera, a peak in flight capacity occurred on Night 4, followed by a decline with increasing age. Long-flying moths (&gt; 5 h duration) were evident in both species from the night following emergence. Attainment of reproductive maturity was rapid in both species, with 91% of H. punctigera and 77% of H. armigera ovipositing by Night 3. Hence, the increase in flight capacity recorded for both species during early adult life is coincident with the onset of reproductive activity. Both species retain the capacity for extensive inter-crop and inter-regional movement throughout most of the reproductive phase of their adult lives. Neither successful mating or the absence of adult food sources influenced flight capacity during early adult life.