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Multiple mating by females is common and often driven by social constraints on female mate choice. However, females mate with multiple males even in systems without these social constraints and rates of multiple mating tend to be highly variable within and between populations. In lek mating systems, females are able to assess multiple males and their choice is unrestricted by pair bonds or the need for biparental care, yet some females mate with multiple males. To better understand the factors affecting variation in multiple mating, we investigated the occurrence of multiple paternity within clutches in a highly polygynous lek mating system. Using long-term data on genetic paternity, survival, social status and individual age from a population of lance-tailed manakins Chiroxiphia lanceolata, a species where males lek in cooperative alpha-beta pairs, we tested five non-exclusive hypotheses about the causes of variation in multiple mating and its benefits in females. We found that inexperienced males, including new alphas and rare beta sires, were disproportionately likely to share paternity when they sired any chicks. In contrast, female age (experience) was unrelated to multiple paternity. Multiple mating did not result in higher reproductive success or reduced variance in success for females, and there were neither consistently promiscuous females nor males that consistently shared paternity. The occurrence of multiple paternity in this lek mating system was best explained by female choice related to male characteristics that change with male experience. Our results support the hypothesis that there is a developmental component to the occurrence of multiple mating, and suggest females choose to mate multiply when their choices are not optimal.

It is well known that female age at first marriage positively correlates with male income inequality. The common interpretation of this fact is that marital search takes longer when the pool of potential mates is more unequal. This paper challenges that interpretation with a novel econometric method. I utilize the fact that the female age at first marriage was shown to be a sum of a skewed term, possibly related to search, and a normally distributed residual. I estimate search duration as the expected skewed term. I find that in the American data this term does not positively correlate with male income inequality and female education.

This study was designed specifically to determine the normal acetabular orientation and femoral head covering, and whether these are affected by age or sex. Computed tomographic images of normal Japanese hip joints were used (males 60, females 60; mean age 48.3 years, range 15-79 years). Male and female age profiles were matched. The reconstructed 3-D pelvic images were aligned in the anatomical pelvic coordinate system. The acetabular orientation angles and femoral covering angles were measured in the sagittal, coronal, and horizontal planes. In the sagittal plane, the acetabular orientation angle was operative anteversion (O-av), and the femoral covering angles were the anterior and posterior center-edge angles (ACE and PCE). In the coronal plane, they were the Sharp angle (SA) and the lateral center-edge angle (LCE). In the horizontal plane, they were anatomical anteversion (A-av) and the anterior and posterior sector angles (ASA and PSA). The O-av, SA, and A-av were smaller in the male than the female acetabulum (P

The seasonal timing of reproduction is a major fitness factor in many organisms. Commonly, individual fitness declines with time in the breeding season. We investigated three suggested but rarely tested hypotheses for this seasonal fitness decline: (1) time per se (date hypothesis), (2) late breeders are of lower quality than early ones (individual quality hypothesis), and (3) late breeders are breeding at poorer territories than early ones (territory quality hypothesis). We used Bayesian variance component analyses to examine reproductive output (breeding success, number fledged, and number of recruits) from repeated observations of female northern wheatears (Oenanthe oenanthe) and individual territories from a 20-year population study. The major part of the observed seasonal decline in reproductive output seemed to be driven by date-related effects, whereas female age and territory type (i.e. known indicators of temporary quality) contributed to a smaller degree. Other, persistent effects linked to individual and territory identity did not show any clear patterns on the seasonal decline in reproductive output. To better disentangle the quality effects (persistent and temporary) of individual and territory from effects caused by the deterioration of the environment we suggest a protocol combining experimental manipulation of breeding time with a variance-covariance partitioning method used here. This article is protected by copyright. All rights reserved.

Received: November 24, 2014; Initial acceptance: December 17, 2014; Final acceptance: January 13, 2015, Despite many studies of how male characteristics affect paternity in predominantly monogamous birds, relatively little attention has been given to the traits of females that may influence extra-pair paternity (EPP). However, the occurrence of EPP may be the result of behavioural interactions in which both male and female traits are important for determining the outcome. If EPP is driven mainly by female choice of extra-pair sires, older, more experienced or larger females would be better able to evade mate guarding tactics and more capable of selecting extra-pair mates and resisting unwanted suitors. This would be especially noticeable in females paired with unattractive mates. On the other hand, if EPP is driven mainly by male pursuit, we should expect that young, inexperienced or small females would be more exposed to coercive male approaches independently of social mate traits. In a study of an Iberian population of the pied flycatcher Ficedula hypoleuca, we found that EPP affected 38% of the broods and 17% of the nestlings. These values are relatively high, allowing a relatively large number of affected within-pair mates to be included. We found that EPP is related to both female and male traits although not to any interaction between male and female traits. EPP was higher at nests tended by both younger and short-winged females and by browner males. Older females may be more experienced and dominant while long-winged females may be faster fliers, these traits enabling them to avoid extra-pair copulations, while brown males are less aggressive towards male intruders. In our study population, EPP appears to be caused by male pursuit, which in some cases may overwhelm female attempts to avoid extra-pair copulations and their social partner's ability to prevent them., The study was ethically approved by the Ethical Committee of CSIC (Spanish Research Council)., At the time of the field study, RRdC was supported by a grant from CSIC, and SGB was supported by a contract grant from Ministerio de Ciencia e Innovación., The study has received financial support from projects CGL2010-19233-C03-02 and CGL2013-48193-C3-3-P to JM (DGI-Ministerio de Ciencia e Innovación).

Double brooding may be a good strategy for short-lived species to maximize annual and lifetime reproductive success (ARS and LRS, respectively). Nevertheless, there is typically individual variation in the probability of producing a second clutch. Here we evaluate factors that influence the decision to double brood in the Eurasian Hoopoe Upupa epops. Analyses of an 11-year dataset showed that 36% of the females and 21% of the males produced a second clutch after successfully raising a first clutch. Double-brooded females had higher ARS (9.1 ± 1.9 fledglings; mean ± se) and LRS (0.93 ± 0.08 recruits) than single-brooded females (ARS: 4.5 ± 2.1 fledglings; LRS: 0.36 ± 0.03 recruits). This suggests that double brooding is adaptive in Hoopoes, and raises the question of why most individuals only produce one clutch per season. The probability of double brooding varied only slightly between years, suggesting that it is influenced by individual characteristics rather than by external, population-level environmental factors. In both sexes, the probability of double brooding increased with earlier timing of the first clutch, and the timing of reproduction was the most important factor influencing reproductive success. The latter is likely to be mediated by changes in resources during the season. The probability of double brooding also increased slightly with female age, due to differences in intrinsic quality among females rather than to a gain in experience. In contrast to many other studies, the probability of double brooding increased with an increasing number of fledglings from the first clutch, suggesting that it is a strategy of individuals of high quality. Taken together, we show that the individual quality of the breeder and the timing of their first clutches are key factors influencing the decision to double brood, and thereby that they are important determinants of reproductive performance in Eurasian Hoopoes.

The number of mature eggs remaining in the ovaries and the time left for oviposition determine the reproductive decisions of the hyperdiverse guild of insects that require discrete and potentially limiting resources for oviposition (such as seeds, fruits or other insects). A female may run out of eggs before all available oviposition sites are used (egg limitation), or die before using all of her eggs (time limitation). Females are predicted to change clutch size depending on whether eggs or time is the limiting resource. We extend this framework and ask whether the same constraints influence a strategy in which females modify eggs into protective shields. In response to egg parasitism cues, female seed beetles (Mimosestes amicus) lay eggs in vertical groups of 2-4, modifying the top 1-3 eggs into shields in order to protect the bottom egg from attack by parasitoids. We made contrasting predictions of how egg and time limitation would influence egg size and the incidence and level of egg protection. By varying access to seed pods, we manipulated the number of remaining eggs a female had at the time she received a parasitism cue. Although egg size was not affected, our results confirm that egg-limited females protected fewer eggs and time-limited females protected more eggs. Female body size explained the number of eggs in a stack rather than host deprivation or the timing of parasitoid exposure. Our results clearly show that host availability relative to female age influences the incidence of egg protection in M. amicus. Furthermore, our study represents a novel use of life history theory to explain patterns in an unusual but compelling defensive behaviour.

Animals that reside at high latitudes and altitudes year-round often use cached food to survive over the winter months, but a few species also rely on stored food to sustain them during the breeding season when the nutritional requirements of females are higher than normal. Gray jays Perisoreus canadensis rely on perishable cached food during the winter and females begin breeding in late winter when fresh food is rarely available. To examine pre-laying patterns of weight gain, as well as the causes and consequences of weight gain among individuals, we weighed females regularly throughout the pre-laying period. Females began increasing their weight approximately nine days prior to their fi rst egg date, and on average increased their body weight by 25%, which is on par with other bird species that rely on non-cached food. Final pre-laying weight was positively infl uenced by the percent of conifers on territories, providing some support for previous results showing that coniferous trees are better able to preserve cached food. We also found that both fi nal pre-laying weight and the rate of weight gain were positively related to female age, supporting the hypothesis that female caching ability improves with age. With increasing fi nal weight, females tended to lay larger clutches and hatched more nestlings, despite the fact that fi nal weight was not infl uenced by weight at the beginning of the weighing period. Our results confi rm that gray jays are able to reach breeding condition while relying primarily on food stored before winter, and suggest a novel mechanism by which habitat-mediated carry-over eff ects and female age may infl uence reproductive performance in a food-caching animal.

The influence of female age on male mating preference and reproductive success has been studied using a promiscuous cabbage beetle, Colaphellus bowringi Baly (Coleoptera: Chrysomelidae). In a simultaneous choice test, middle-aged females had significantly greater mating success than young and old females. In single pair trials, when paired with middle-aged virgin males, middle-aged females mated faster, copulated longer, and had greater fecundity and fertility than young or old females, while the longevity of males was not significantly affected by female age. This study on C. bowringi suggests that middle-aged females are more receptive to mating, which can result in the highest male reproductive success.

Summary Traditionally, many breeding traits (e.g. the timing and size of clutches) were considered to be female-only traits in that males played little-to-no role in their expression. Although the contribution of males to such breeding traits, as well as other aspects of reproduction, is increasingly recognized, few studies have demonstrated the effects of male age and life history on breeding traits and, importantly, whether these effects are underlined by additive-genetic variation. Here, we take advantage of a long-term data set on mute swans (Cygnus olor) to demonstrate that the ages of both the male and female parents play significant roles in the timing and size of clutches, although recruitment success did not show similar effects. Individual males varied significantly in their influence on the timing of egg laying. We decomposed this variation using an ‘animal model’; competing models that were the source of this variation as additive-genetic or permanent-environmental variation was not statistically distinguishable. Our results add to the growing evidence that reproductive performance should be considered as a product of the identity and condition of both parents.

Fifty-two eyes were collected and analyzed to estimate ages of 42 bowhead whales using the aspartic acid racemization aging technique. Between-eye and within-eye variance components for the ratio of the D and L optical isomers (D/L ratio) were estimated via analysis of variance using multiple measurements from nine whales with both eyes sampled and analyzed. For whales with more than one (D/L)act value, an inverse variance weighted average of the values was used as (D/L)act for the whale. Racemization rate (kAsp) and D/L ratio at birth (D/L)0 were estimated using (D/L)act from 27 bowhead whales with age estimates based on baleen or ovarian corpora data and two term fetuses. The estimates were kAsp = 0.977 × 10−3/yr and (D/L)0 = 0.0250. The nonlinear least squares analysis that produced these estimates also estimated female age at sexual maturity as ASM = 25.86 yr. SE(age) was estimated via a bootstrap that took into account the SE of (D/L)act and the variances and covariance of kAsp and (D/L)0. One male exceeded 100 yr of age; the oldest female was 88. A strong linear relationship between kAsp and body temperature was estimated by combining bowhead data with independent data from studies of humans and fin whales. Using this relationship, we estimated kAsp and ASM for North Atlantic minke whales.

Reproductive and survival records (n = 2,913) from 313 Chinese-origin and 365 Indian-derived rhesus macaques at the Tulane National Primate Research Center spanning 3 generations were studied. Least-squares analysis of variance procedures were used to compare reproductive and infant survival traits while proportional hazards regression procedures were used to study female age at death, number of infants born per female and time from last birth to death. Chinese females were older at first parturition than Indian-females because they were older when placed with males, but the two subspecies had similar first and lifetime post-partum birth intervals. Females that gave birth to stillborn infants had shorter first post-partum birth intervals than females giving birth to live infants. Post-partum birth intervals decreased in females from 3 to 12 years of age but then increased again with advancing age. Chinese infants had a greater survival rate than Indian infants at 30 d, 6 mo and 1yr of age. Five hundred and forty-three females (80.01 %) had uncensored, or true records for age at death, number of infants born per female, and time from the birth until death whereas 135 females (19.91 %) had censored records for these traits. Low and high uncensored observations for age at death were 3 and 26 years of age for Chinese and 3 and 23 years of age for Indian females. Uncensored number of infants born per female ranged from 1 to 15 for Chinese females and 1 to 18 for Indian females. Each of these traits was significantly influenced by the origin × generation interaction in the proportional hazards regression analyses, indicating that probabilities associated with age at death, number of infants born per female and time from last birth to death for Chinese and Indian females did not rank the same across generations.

The role of human capital in economic growth is now largely uncontested. One indicator of human capital frequently used for the pre-1900 period is age heaping, which has been increasingly used to measure gender-specific differences. In this note, we find that in some historical samples, married women heap significantly less than unmarried women. This is still true after correcting for possible selection effects. A possible explanation is that a percentage of women adapted their ages to that of their husbands, hence biasing the Whipple index. We find the same effect to a lesser extent for men. Since this bias differs over time and across countries, a consistent comparison of female age heaping should be made by focusing on unmarried women.

Union of the vertebral centra or "ring" epiphyses occurs during adolescence and early adulthood, providing valuable age at death information. We present a system for estimating age based on the timing and pattern of vertebral ring union. Data from 57 known individuals aged 14-27 years were used to establish age ranges for various patterns of union in females and males. Female age ranges were more well defined with less overlap in patterns of union than male age ranges. The age ranges are accompanied by descriptions of the stages of union observed that aid in applying this method. A test of interobserver error in scoring stages of union demonstrated strong consistency among three observers (r = 0.91-0.97). Estimating age by observing all stages documented resulted in 78%, 88%, and 100% accuracies using vertebral data alone. We encourage the continued use of this method, in conjunction with other age indicators.

Giant grenadiers Albatrossia pectoralis are caught as bycatch in deep-sea commercial fisheries in relatively large numbers. The population appears to be stable, although there is no directed fishery, catch limits, or reporting requirements. The purpose of our study was to describe and quantify the reproductive life history characteristics and natural mortality of female giant grenadiers. During the summers of 2004 and 2006, a total of 338 specimens were collected from the Gulf of Alaska. Every phase of reproductive development was found, suggesting a protracted annual spawning season. An ovarian wall thickness technique was used to successfully place 31% (n = 24) of the fish with an unknown maturity status into a known category. Female age at 50% maturity was 22.9 years, and preanal fin length at 50% maturity was 26 cm. Total fecundity ranged from 35,000 to 231,000 oocytes (mean = 106,761), with a mean mature oocyte diameter of 1.26 mm. We developed a new technique for preparing otoliths for age ...

House flies, Musca domestica L., were collected in copula over two summers from six dairies located in three climatically distinct regions in the U.S.A. southern California, Minnesota and Georgia. Ages of males and females from a total of 511 mating pairs were estimated using pterin analysis. Cuticular hydrocarbon profiles and gonotrophic ages of females also were evaluated. Mean age of mating males ranged from 54 to 102 degree-days (DD) (4-10 days based on field air temperatures), depending on the farm. Very young males (10-20 DD) and old males (200 DD) were rare in mating pairs. Mean female age at mating ranged from 20 to 46 DD (2.5-4 days). All mating females had eggs in the early stages of vitellogenesis and 99.2% were nulliparous. However, some older and parous females were collected, demonstrating that re-mating can occur in the field. Head width measurements of mating pairs suggested that assortative mating by size did not occur. The cuticular hydrocarbon profiles of females were determined, with emphasis on (Z)-9-tricosene (muscalure). Overall, only 55% of mating females had detectable amounts (4 etag per fly) of (Z)-9-tricosene. Of the females that had detectable (Z)-9-tricosene, variation in amount per female was high in all fly populations, and thus was not statistically related to the size or age of the mating female. The proportion of mating females with detectable levels of (Z)-9-tricosene varied by geographic region. Seventy-one, 63, and 27% of females from southern California, Minnesota and Georgia had detectable amounts of (Z)-9-tricosene. Principal components analysis of the eight most abundant hydrocarbons from mating females, by state, revealed state-level distinctiveness of hydrocarbons in house fly populations, which may reflect genetic variation associated with environmental stresses in those geographical zones.

Senescence is the deterioration of the phenotype with age caused by negative effects of mutations acting late in life or the physiological deterioration of vital processes. Birds have traditionally been assumed to senescence slowly despite their high metabolic rates, high blood sugar levels and high body temperature. Here we investigate the patterns of age-related performance of sperm of a long distance migrant, the barn swallow Hirundo rustica, varying in age from 1 to 6 years, analysed by the computer-assisted sperm analysis equipment. Sperm showed deteriorating performance in terms of linear movement, track velocity, straight line velocity and reduced proportions of rapidly moving, progressive and motile sperm with age. In a second series of experiments, we assessed performance of sperm from the same males in neutral medium and in medium derived from the reproductive tract of females in an attempt to test if sperm of old males performed relatively better in female medium, as expected from extra-pair paternity being negatively related to male age, but not to female age. Older males showed consistently better performance in female medium than in neutral medium in terms of track velocity, straight line velocity and reduced proportions of rapidly moving, progressive and motile sperm, whereas young males showed better performance in neutral medium. These results provide evidence of declining sperm performance for important reproductive variables not only with age, but also with the sperm of old males performing differentially better in female medium than young males.

We studied the relationship among re-mating, site fidelity and breeding performance in the tree swallow Tachycineta bicolor using 16 y of data on reproductive biology in a population breeding in nest boxes near Ithaca, New York. Of 217 pairs for which both members survived the non-breeding season, 76% mated with a new partner and 24% reunited with their previous mate. Pairs did not increase their breeding success by breeding together for more than one breeding season. Males produced fewer fledglings after breeding with a new partner, but females neither increased nor decreased their success when breeding with a new mate. Females who bred with a new partner were younger than females that reunited with their previous mates, and they were more likely to move to a different nest box. Males that bred with a new mate were of similar age to males that reunited, and they did not move more often. The probability of breeding with a new partner was better predicted by female age than by previous breeding success, suggesting that re-mating was not strongly affected by past breeding performance. Because younger females change breeding sites more frequently than do older females and females that mated with a new partner were younger than females that reunited with their previous mates, we suggest that the tendency of tree swallows to change partners between years is a by-product of lower site fidelity of younger females rather than a strategy for increasing breeding success.

Supplemental food in the form of millet seed was provided to 1-year-old and older (2:2-year-old) female Alpine Accentors Prunella collaris, and the effect on timing of breeding was studied over four breeding seasons in central Japan. Only 1-year-old females responded to the supplemental food: additional food advanced their settlement date, the onset of the development of a cloacal protuberance and laying date. In contrast, no effect of the experimental feeding was found on the timing of breeding in older females and they invariably bred earlier than 1-year-old females. Having settled on the breeding grounds, females developed the cloacal protuberance and retained it for about 1 month until the last egg in the first clutch was laid. The development period of the protuberance corresponded to the copulation period. Because the copulation period was not shortened by extra food and no significant difference occurred in either of the two age classes, it is necessary for earlier breeding birds to accumulate the nutrients needed to form the protuberance as well as the eggs. Although older females relied less on supplemental food, they were significantly heavier and formed the cloacal protuberance earlier than 1-year-old females. One-year-old females depended more heavily on supplemental food than did older ones and the duration between settlement date and the onset of development of the protuberance of 1-year-olds was reduced by additional food. These results raised the possibility that older females fly from their wintering grounds carrying some food reserves which they can use for forming the protuberance, while 1-year-old females collect the food needed for forming it on the breeding grounds.

In the Marsh Tit Parus palustris, breeding performance improved with the age of both the male and the female parent-older birds produced larger clutches earlier in the season. The effect of male age, however, was mainly due to a positive association with the age of the female. When the effect of laying date was accounted for, there was no additional effect of female age on clutch-size. However, pairs with previous breeding experience laid larger clutches than newly formed pairs of the same age. There was some evidence that young females that laid late in the season were less likely to survive to breed again, leading to an age effect on reproductive performance. There was no evidence that individual birds laid earlier or produced larger clutches when they became older. (Less)

1. With the aid of a novel survivorship model, an 8-year field study of social and maternal factors affecting duckling survival in eiders (Somateria mollissima) revealed that duckling survival probability varies in accordance with maternal brood-rearing strategy. This variability in survival provides compelling evidence of different annual fitness consequences between females that share brood-rearing and those that tend their broods alone. Consequently, as prebreeding survival is often a major source of individual variation in lifetime reproductive success, a female's annual, state-dependent (e.g. condition) choice of a brood-rearing strategy can be a critical fitness decision. 2. Variance in duckling survival among lone tender broods was best explained by a model with significant interannual variability in survival, and survivorship tending to increase with increasing clutch size at hatch. Clutch size was correlated positively with female condition. Hatch date and female body condition together affected duckling survival, but their contributions are confounded. We were unable to identify a relationship between female age or experience and duckling survival. 3. Variance in duckling survival among multifemale brood-rearing coalitions was best explained by a model that included the number of tenders, the number of ducklings and interannual variation in how their ratio affected survivorship. Hatch date did not significantly influence survival. 4. Expected duckling survival is higher in early life for lone tenders when compared with multifemale brood-rearing coalitions. However, as ducklings approach 2-3 weeks of age, two or three females was the optimal number of tenders to maximize daily duckling survival. The survivorship advantage of multifemale brood-rearing coalitions was most evident in years of average survival. 5. The observed frequency distribution of female group sizes corresponds with the distribution of offspring survival probabilities for these groups. Evidence for optimal group sizes in nature is rare, but the most likely candidates may be groups of unrelated animals where entry is controlled by the group members, such as for female eiders. 6. Our study demonstrates that differences in social factors can lead to different predictions of lifetime reproductive success in species with shared parental care of self-feeding young.

Mortality analyses commonly disregard postmenopausal acceleration. This study examined period log mortality in World Health Organization (WHO) data for 34 low-mortality countries in 2000, demonstrating significant gradient increases for women (33/34 countries) and men (22/34), from a later age than previously reported, dividing the postmenopausal period into phases. "Break points" were identified as intersects of lines of best fit to these and the same approach was used in analysis of Human Mortality Database data for 19 countries. There has been an upward migration of about 10 years in female age at break point since 1850. Male data flipped from mortality acceleration to deceleration and back in the late 20th century with no apparent shift in break point. Altered age at mortality acceleration appears genuine, gender-specific, and internationally consistent. Its timing prompts the hypothesis that it may relate to falling fertility.

There is little quantitative information concerning the number and distribution of bone-matrix resorbing osteoclasts (BMRO) within the adjacent alveolar bone coincident to tooth movement. We moved the right first maxillary molar tooth anteriorly in 40 female rats (E), the left side was untreated, serving as an internal control (IC). Forty female age and weight matched rats were untreated, serving as external controls (EC). BMRO were identified on periosteal and endosteal surfaces of the interdental septum from 1-5 days after initial force application using the MTB-322 antibody. The number of BMRO at periosteal surfaces of E was greater in IC and EC from 2-5 days (P < 0.001). Similarly, the number of BMRO at endosteal surfaces was greater from 1-5 days (P < 0.001). The number of BMRO at periosteal and endosteal surfaces was greater within E than within EC from 1-5 days (P < 0.001). Outcome data from IC were often significantly different from EC. Our data suggest that relatively low forces increase the number of BMRO, which are not uniformly distributed onto both periosteal and endosteal surfaces. Thus, the interdental septum resorbs at the alveolar wall and within spaces between the trabeculae, which, taken together, results in net removal of bone from areas of compression. These data also suggest that experimental tooth movement produces significant differences in the number and distribution of BMRO within IC and EC. Thus, EC groups should be included in studies of tooth movement.

The effect of both male and female age was investigated on certain reproductive attributes, viz. mating incidence, mating duration, fecundity, percent egg viability, ratio of reproductive and non-reproductive periods and reproductive rate, of an aphidophagous ladybird, Cheilomenes sexmaculata (Fabricius). Females started mating at the age of 8 hours post-emergence (PE) and males at the age of 2 days PE. Mating in the laboratory was a male-dominated phenomenon. The mating duration and reproductive rate of 10-day-old females when mated with males of varying ages increased up to the male age of 60 days, and thereafter decreased, whereas, fecundity, egg viability and ratio of reproductive and non-reproductive periods increased up to the male age of 50 days, and thereafter declined. However, when females of varying ages were mated with 10-day-old males, fecundity and reproductive rate increased up to 40 days of female age, respectively, then decreased. The ratio of reproductive and non-reproductive periods increased with increasing age of females. Mating age for optimal reproductive output was 10J50-day-old males and NE to 40-day-old females. Reproductive cessation in males was recorded after 50 days PE, whereas in females at the age of 40 days PE. Higher mating durations lead to elevated reproductive rates. Delay in the reproductive phase was positively correlated with longevity. The results of this study may aid mass multiplication of this ladybird by identifying and promoting usage of adults of optimal age. Our results also enhance our understanding of the effect of age on reproductive attributes in ladybirds.

The continental population of northern pintails (Anas acuta; hereafter pintails) has declined since the late 1970s, possibly due to poor breeding propensity, low nest success, and low survival rates in response to habitat loss. Survival estimates are unavailable for several winter and migration areas including the Playa Lakes Region (PLR) of northwestern Texas, USA. We investigated winter survival rates, documented periods of mortality, and identified possible causes of mortality for 159 and 168 radiotagged female pintails during 23 October 2002–18 February 2003 and 10 October 2003–18 February 2004, respectively. We located all radiotagged pintails at least once weekly to verify survival status and used-known fate modeling in program MARK to test the influence of capture period, female age class, body mass, and capture location on survival rates. Cumulative survival for the 119-day period in 2002–2003 was 0.925 (95% CI = 86.0–96.3). During 2003–2004, for a 134-day period, survival estimates decli...

Duckling survival is an important component of waterfowl population dynamics, and we provide the first-known estimates of duckling survival for common goldeneyes (Bucephala clangula) at the northern limit of their range in Interior Alaska. We color-marked common goldeneye ducklings from 91 broods and radio-marked a subset of the females (n = 39) from a nest-box population in the boreal forest during the summers of 2002 and 2003. We monitored 46 broods in 2002 and 2003 combined and estimated daily survival rates (DSR) and survival to 30 days of age using program MARK. We modeled DSR in relation to year, linear trend across season, duckling age, female age, female body condition, initial brood size, and daily precipitation. Model-averaged duckling survival estimates from the mean yearly hatch date to 30 days of age were 0.64 (95% CI, 0.37–0.90) and 0.67 (95% CI, 0.54–0.80) for 2002 and 2003, respectively. Our best-approximating model indicated that survival differed by year and increased in a linear manner over the course of the 2002 season. Precipitation had a consistent negative effect on duckling survival in both years across models, whereas duckling age did not explain much of the variation in daily survival rates. In light of the decline of many populations of sea ducks, we suggest that more effort should be expended to obtain estimates of other population parameters for common goldeneyes, and monitoring programs should attempt to estimate populations more precisely to identify population-level changes in the future.

With reference to models predicting patterns of reproduction in multi-brooded species, I analysed some of the factors potentially affecting the number of breeding attempts per season made by female Black Redstarts Phoenicurus ochruros in the central Swiss Alps. The maximum number of successful broods per female per season was three, the median two. The proportion of females initiating only a single clutch per season varied from 16 to 58% over 10 years. Variation in the frequency of single brooding between years was positively related to the date of the onset of breeding. Egg-laying started after a temperature-related threshold value was crossed in April. Females frequently re-nested before fledglings of the previous brood were independent. Short interbrood intervals were associated with triple brooding. The interbrood interval shortened during the breeding season. Intra-individual variation in the number of breeding attempts per season was partitioned according to female age, laying date of the season's first egg (standardized in relation to the median date of first laying within a year) and the occurrence of breeding failures before the ultimate nesting attempt. However, mortality during the season often terminated breeding early, in particular among novice breeder females. Seasonal reproductive success increased linearly with each additional breeding attempt. The productivity of a breeding attempt was independent of the time in the season. Increased reproductive effort affected neither current or future survival nor reproduction of females. The reproductive patterns and trade-offs in multi-brooded Black Redstarts contrast in many aspects with those found in single-brooded species. They are in accordance with models predicting that multi-brooded species are selected to start breeding as early as possible, continue breeding for as long as conditions are suitable, and save time by overlapping broods.

A population of bullhead Cottus gohio inhabiting a mountainous river network, was examined for the influence of maternal condition (total length, L T , and age class in years) and environmental factors (water temperature and fish density) on fecundity, egg size and net annual reproductive effort (E R , defined as the ratio of total egg production mass to body mass) within several stocks. Regardless of location within the drainage network, bullhead reproduction was synchronous, with only a single batch and fecundity ranging from 69 to 896 eggs per female. As with L T fecundity increased with age, although the difference between age classes 5 and 6 years was smaller than between other age classes. Egg diameter also increased with age from age classes 2 to 4 years, but then tended to decrease for age classes 5-6 years. Multiple stepwise regression was used to examine the effect of female L T , water temperature and fish densities on bullhead egg production for each of the four age classes (2, 3, 4 and 5-6 years) separately. When statistically significant, water temperature always had a positive effect and fish densities a negative effect, on fecundity and egg size. The L T always had a positive effect on fecundity for all the age classes. In contrast, L T had a positive effect on egg size and E R only for female reaching maturity (2 years), whereas intermediate aged females (3-4 years) were insensitive and the oldest fish showed a negative response.

Varicocele represents the most common cause of male infertility, and most reports indicate that varicocelectomy has a beneficial effect on male fertility and pregnancy outcome. Assisted reproductive technologies (ARTs) are an alternative to varicocelec- tomy for the management of couples with a varicocele. The age of the female partner is important in the decision-making process; how- ever, the true influence of female age on pregnancy outcome follow- ing varicocelectomy or ART in these couples is unknown. We eval- uated the outcomes of 2 cohorts of infertile men with a varicocele and a female partner 35 years of age or older; one group selected varicocelectomy and the other a nonsurgical approach. We reviewed a group of consecutive infertile men who underwent microsurgical varicocelectomy and whose partners are 35 years of age or older (n 5 110). We also reviewed a consecutive group of men with vari- coceles who elected not to have surgery and whose partners are 35 years of age or older (n 5 94). The outcome measures included changes in semen parameters, pregnancy rates (assisted and un- assisted), and use of ART. The surgical and nonsurgical groups had comparable semen parameters and female ages. Mean sperm con- centration and motility increased significantly after varicocelectomy (P , .05). At a mean of 30 months follow-up, 35% of couples in the surgical group achieved a spontaneous pregnancy and an additional 6% achieved a pregnancy via ART (20% of this group attempted ART). In the nonsurgical group, 25% achieved a spontaneous preg- nancy and an additional 16% achieved a pregnancy with ART (40% of this group attempted ART). This study on the natural history of infertile men with varicocele and advanced female age suggests that the surgical and nonsurgical approaches offer comparable pregnan- cy outcome (combined assisted and unassisted pregnancy rates are about 40%). Overall, these data suggest that varicocelectomy is an acceptable option for couples with advanced female age, but other female factors must be considered in the decision-making process.

We compared the incubation behaviour of 1-year-old female Savannah Sparrows Passerculus sandwichensis nesting for the first time with that of older females that had nested in previous years on Kent Island, New Brunswick, Canada. Using temperature probes inserted into 32 nests, we determined the length and variability of incubation shifts and recesses over 99 nestdays. At 14 of the nests, known-age females were matched, each pair consisting of an inexperienced yearling and an experienced older female, and nest temperatures were measured simultaneously. In addition, we quantified the duration of night-time incubation and the mean length and variation of more than 1350 incubation shifts and recesses as a function of female age, weather, time of day and date. In all respects, yearling and older females had equivalent incubation behaviour. The similarity between yearlings and older females suggests that fundamental aspects of incubation behaviour may be largely innate and unaffected by prior reproductive experience or other age-related variables.

I used data from a 13-year study of eastern kingbirds Tyrannus tyrannus from central New York, USA, to evaluate the relative impact of female age and body size on reproduction. I also calculated repeatabilities of reproductive traits for both females and the sites where they bred in an attempt to evaluate the relative contribution of each to intrapopulation variation in reproduction. Female age had a strong influence on timing of breeding (breeding date advanced by one day for each year of life), but was not a significant source of variation for clutch size, egg mass, number of young to hatch or fledge, or total seasonal production. Repeatabilities of breeding date for females and sites were both significant (0.284 and 0.181, respectively), but the only other significant repeatabilities were for female clutch size (0.282) and female egg mass (0.746). Among-year repeatabilities of breeding date for females who bred at two or more sites over their lifetime were as high as those for females that were site faithful. Thus, breeding date was probably affected independently by the female and site. No measure of productivity exhibited a repeatable pattern in comparisons made among females or sites. All reproductive traits were entered as dependent variables in a series of stepwise multiple regression analyses in an attempt to identify female properties (size, lifespan and condition) that might be linked proximately to differences in breeding statistics. I found that (a) large birds tended to breed the earliest, (b) clutch size was independent of female size, condition and lifespan, (c) female body size and egg size were correlated positively, but (d) production of young was independent of all measured female properties. Reproduction appears to be linked more closely to the female than to the site. Body size accounts for a portion of the repeatable portion of breeding date and egg mass, but most of the intrapopulation variation in these and other traits remained unexplained.

We studied the correlations between offspring sex ratio, UV coloration and overwinter survival in a population of blue tits, breeding in Gotland, Sweden, over three consecutive breeding seasons. In 2 of 3 years, we found that females paired to males with relatively brighter UV-coloration produced a greater proportion of sons in their broods, and that this effect was significant with all 3 years combined, despite a significant year by male UV interaction. In addition, we found other correlates of sex ratio (breeding time, female age and clutch size) in some, but not all years, and some of these showed significantly different relationships with sex ratio between years. In both years for which data were available, there were indications that males with relatively brighter UV coloration, and that paired with females that produced male-biased clutches, were more likely to survive to the next year. In addition, we also found that in both males and females, individuals produced similar sex ratios in consecutive years. Because correlations with the sex ratio may be expected to be weak, variation in results between years within the same population may be explained by low statistical power or genuine biological differences. Our results suggest that conclusions about sex ratio variation in birds should be based on multiple years. The correlations that we found in some years of this study are consistent with models of adaptive sex ratio adjustment in response to mate quality. However, careful experimental work is required to provide tests of the assumptions of these models, and should be a priority for future work.

The age-specific reproductive performance of Northern Goshawks Accipiter gentilis was studied over 22 years in Denmark. The age of the breeding female in relation to the number of young raised was known in 929 breeding attempts, while the age of both the male and the female was known in 496 breeding attempts. The number of fledglings raised per breeding attempt increased with both male and female age, but only for females was it possible to conduct a detailed analysis of this age-dependent relationship. The annual production of fledglings increased with female age from 1 to 7 years of age, whereupon it started to decline. A longitudinal analysis showed that this mean population trend could be attributed to similar age-related trends in individual females. Previous breeding experience did not influence the number of fledglings produced by individual females, and poorly performing females apparently survived with the same probability as well performing ones. The most likely explanation for the age-dependent reproductive performance in the observed Goshawk population appeared to be age-related improvements in competence, such as foraging efficiency.

We investigated courtship feeding and copulatory behaviour of common terns Sterna hirundo in relation to age. We found a significant positive correlation between the number of courtship feedings delivered to females and the number of mountings. Moreover, both courtship feeding and mounting rates were positively correlated with female and male age. Also, the number of cloacal contacts per mounting increased significantly with male or female age, which may indicate an increase in copulatory ability with age. The number of mountings for older birds was up to three times that for younger birds. Presuming that transfer of sperm is proportional to the number of cloacal contacts, older birds may have transferred up to six times more sperm than younger birds during the pre-laying and laying period. These results may account for the preference of young females for older mates as well as for older extra-pair mates.

Is a man’s sexual peak earlier than a woman’s? Three studies were conducted to examine (a) whether the perception that men achieve their sexual peak at a younger age than do women is shared across individuals of different ages and sexes, (b) whether sexual peak is defined differently for men and women, and (c) whether differences between definitions contribute to differences in the age at which men and women are perceived to reach sexual peak. Study 1 suggested that participants believed that females reach their sexual peak at an older age than do males. Study 2 indicated that the defining feature of sexual peak for males was sexual desire and for females was sexual satisfaction. Study 3 suggested that predictions of male sexual peak coincided with participants’ predictions of male age of highest desire and frequency, but not satisfaction, and that female sexual peak coincided with participants' predictions of female age of highest satisfaction but not frequency or desire. Discussion focuses on potential reasons for differences between the perception of male and female sexuality, as well as the social and evolutionary importance of each of the dimensions of sexuality for both males and females.

The objective was to study patients of Aboriginal and Torres Strait Islander origin who were admitted to Cairns Base Hospital with the diagnosis of femoral neck fracture. An analysis of all 232 admissions with this diagnosis between November 1997 and July 2000 was carried out. Information was gathered from data accumulated on the Clinical Pathways database; other local data was also considered. Patients registered as being of Aboriginal and Torres Strait Islander origin have a lower incidence of these fractures than might be expected on an overall population basis, but similar rates on age-standardised data. The female age profile is substantially older than the female non-indigenous osteoporotic fracture group. Indigenous females develop osteoporotic type fractures of the femoral neck at a later age than do non-indigenous females. This may reflect a genetic difference in bone mineral density or a healthy lifestyle in earlier days. Further research is suggested.

Summary 1 Many studies of cooperatively breeding birds have found no effect of group size on reproductive success, contrary to predictions of most adaptive hypotheses. A model is proposed for variation in group-size effects: group size has a reduced effect on success when conditions for breeding are good, such as in good environmental conditions or in groups with older breeders. This hypothesis is tested with a case study of white-browed scrubwrens Sericornis frontalis and a review of the literature. 2 The scrubwren is a cooperatively breeding passerine with male helpers. Previous analyses revealed no effect of group size on reproductive success, but those analyses were restricted to groups with older females (Magrath & Yezerinac 1997). Here 7 years’ data are used to contrast the effect of group size on reproductive success for yearling and older females. 3 Yearling females breeding in groups had more than double the seasonal reproductive success than those breeding in pairs, even after controlling for territory quality. However, group size still had no effect on the reproductive success of older females. Yearling females tended to survive better in groups, but older females tended to survive better in pairs, emphasizing this pattern. 4 Yearlings breeding in pairs were more likely to be found on poor-quality territories than those breeding in groups, exaggerating the already-strong effect of group size on yearling success. Older females were not affected significantly by territory quality. 5 Group size, territory quality and female age affected different components of seasonal reproductive success. Group size increased the success of individual nesting attempts, while both territory quality and female age affected the length of the breeding season, and thus the number of breeding attempts. 6 A sample of the literature on cooperative breeders shows that group size has a larger effect on reproductive success in poorer conditions, caused either by younger, inexperienced breeders or poorer environmental conditions. Scrubwrens therefore illustrate a widespread pattern, which provides an explanation for much of the variation in group-size effects among and within species. Clearly single estimates of group-size effects for species can be inadequate to test ideas about the evolution of cooperative breeding.

The breeding performance of individually colour-ringed Lapwings Vanellus vanellus was studied on marginal grassland in Upper Teesdale, County Durham (UK), from 1992 to 1995. Contrary to many studies of birds, female age had only a minor effect on breeding performance: yearling females produced eggs on average 5% smaller than those of adults. In contrast, the average productivity of male Lapwings was estimated to increase by around 40% between one and two years of age, and by a further 10% between two and three years of age. This was because of a 40% increase in the proportion of males that bred between one and two years of age, and of an increase in mating success with age coupled with a higher breeding success for polygynous males. The likelihood of breeding for male Lapwings was affected by year of hatching. More than half of those males that hatched in 1990, and which were present in both 1993 and 1994, did not breed. It was suggested that this was due to environmental effects experienced by these males as chicks, resulting in reduced success in securing a breeding territory later in life. Individual female Lapwings showed a high degree of consistency between years in both laying date and egg size, and those that raised up to two young in 1993 raised approximately the same number in 1994. However, females producing more than two young in 1993 raised significantly fewer in 1994, perhaps suggesting a cost of reproduction.

Female calling behaviour and male response to natural and synthetic pheromone sources were used for a Portuguese population of the winter pine processionary moth Thaumetopoea pityocampa (Den. & Schiff.). Virgin females 1–5 days old were studied, the mean calling longevity being 3.3 ± 0.7 days. Calling started ≅ 3 h after the onset of scotophase, and 7 h after emergence, lasting, nightly, for 6.4 ± 0.7 h, and was not affected by female age. A drop in air temperatures during the first half of scotophase and an increase in light intensity at dawn apparently determined the onset and termination of calling. Male flight activity began, on average, 3 h before the females started emitting pheromone, and was similarly affected by air temperatures and light intensity. The attractivity of traps baited with synthetic pheromone (TP056A; Yne 11, Z13–16AC) was compared with that of virgin females. Male flight activity was monitored in central and southern Portugal, using pheromone traps, and seen to last between 6 and 10 weeks, with a major peak occurring, in all sites, at the beginning of September.

The breeding performance in yearling and adult female black grouse Tetrao tetrix was studied in a 6–7 year cyclic population during 1989–93 in central Finland. Eighty yearlings and 108 adults, radio-marked in late winter, survived until the breeding season. Adults were larger, had more body mass at capture, initiated laying earlier and had larger eggs and clutches than yearlings. Yearlings and adults lost 11.8 and 20.9%, respectively, of their first nests to egg predators. Hatching dates and success of eggs were similar for both age classes. The proportion of females losing the entire brood was 32% for yearlings and 27.1% for adults. Brood size in late summer and number of chicks produced per female initiating breeding did not differ between age classes.

Eggs of the Cape petrel Daption capense at Nelson Island, South Shetland Islands, Antarctica, exhibited high variability in volume between females (up to 48%), while for each individual female, both volume and shape of eggs were highly correlated over two seasons. Both female size and body-condition at laying were unrelated to egg-volume in the ‘good’season 1991, but larger females produced larger eggs in the ‘bad’season 1990, when eggs were smaller on average. In 1991, females in better body-condition, but not larger, started laying earlier. In spite of synchronized laying (75% of eggs laid within five days), egg-volume decreased with laying date. Egg-volume differed significantly between the two years, which could not be explained by changes in the breeding population or timing of breeding. The laying of relatively small eggs and low overall breeding success in 1990 most probably reflected changes in food availability. Overall hatchability was 88% and did not differ significantly between disturbed and control colonies in 1991. Larger and more rounded eggs showed better hatching success, but hatchability was related more to egg-volume whereas hatching rate was related more to egg-shape. As the majority of egg losses were attributable to predation, the hatching rate was influenced by parental performance relatively more than by hatchability. Hence the relationship between hatching rate and egg-shape probably reflects improvement in hatching success with female age/experience, whereas the relationship between egg-size and hatchability suggests effect of egg-size independently of parental traits.

Responses of the apple maggot fly, Rhagoletis pomonella (Walsh), to 8 cm red sticky sphere traps, baited with the synthetic fruit odor butyl hexanoate, were investigated in field-caged apple trees containing green or red Gravenstein apples. Trap capture rate and the probability of oviposition in apples before capture generally increased with female age and number of mature eggs in ovaries. Two days of pre-test exposure of mature females to red hawthorns, green Red Delicious apples or green Gravenstein apples had no significant effect on the likelihood of a fly finding a red sphere. However, before capture on a sphere or departing a tree, hawthorn-exposed females found significantly fewer apples and laid significantly fewer eggs than females exposed to Gravenstein apples. Variation in duration of pre-test exposure (1–4 days) of flies to Gravenstein apples had no detectable influence on female response to apples or to a red sphere in a test tree. The relevance of these findings to effectiveness of sphere traps for R. pomonella control in commercial orchards is discussed.

The house finch (Carpodacus mexicanus) is a sexually dichromatic passerine in which males display colorful plumage and females are generally drab brown. Some females, however, have a subdued version of the same pattern of ornamental coloration seen in males. In previous research, I found that female house finches use male coloration as an important criterion when choosing mates and that the plumage brightness of males is a reliable indicator of male nest attentiveness. Male house finches invest substantially in the care of young and, like females, stand to gain by choosing high-quality mates. I therefore hypothesized that a female's plumage brightness might be correlated with her quality and be the basis for male mate choice. In laboratory mate choice experiments, male house finches showed a significant preference for the most brightly plumaged females presented. Observations of a wild population of house finches, however, suggest that female age is the primary criterion in male choice and that female plumage coloration is a secondary criterion. In addition, yearling females tended to have more brightly colored plumage than older females, and there was no relationship between female plumage coloration and overwinter survival, reproductive success, or condition. These observations fail to support the idea that female plumage coloration is an indicator of individual quality. Male mate choice for brightly plumaged females may have evolved as a correlated response to selection on females to choose brightly colored males.