Suppression of reproductive development and longevity in the redshouldered leaf beetle,Monolepta australis (Col.: Chrysomelidae) by the tachinid,Monoleptophaga caldwelli (Dipt.)

This paper examines the level and seasonal incidence of parasitism of the redshouldered leaf beetle,Monolepta australis (Jacoby), by the tachinid,Monoleptophaga caldwelli Baranov, and assesses the impact of this fly on the beetle's reproductive development and longevity. Highest average numbers ofM. australis were trapped at light in north Queensland in January and February while parasitism peaked at 6.6 and 6.8% in June and July respectively, averaging 4.8% over the entire sampling period and reaching 28% for a single occasion. Overall, only 2.4% of parasitized beetles were represented in the final two stages of ovarian development compared to 29.1% of non-parasitized ones. There was a highly significant (P<0.001) difference in the distribution frequencies of parasitized and non-parasitized females in the various stages of ovarian development, and most parasitized males possessed atrophied testes. For field-collected beetles maintained in the laboratory, average longevity for those parasitized was 15.6 days compared to 72.2 days for those not parasitized.     

Initial reproductive investment and parental body size in Cryptocercus punctulatus (Dictyoptera: Cryptocercidae)

Abstract. Females of the subsocial woodroach Cryptocercus punctulatus Scudder generally have a single oviposition period during which they produce one to four oöthecae. Monogamous pairs and their recently deposited oöthecae were collected in the field, and measured, weighed and analysed for nitrogen in the laboratory. Females put 9.8 ± 2.4% (mean ± SD) of their dry weight and 11.6 ±0.5% of their body nitrogen into oöthecae. The total nitrogen and dry weight of the brood were positively related to the post-oviposition total nitrogen and dry weight of the mother. A female's investment, on a per nymph basis, averaged 0.06% of her post-oviposition dry weight. Females may be able to recover up to 58.7% of the nitrogen invested into a brood by consuming the egg cases after hatch. Overall, there was little variation in the width of head capsules of adults in this species, and this parameter was not significantly different between the sexes. Females were heavier than males (dry weight) (P = 0.06). Within pairs, the weights and nitrogen contents of males and females were positively correlated, probably because they feed together in the same log for nearly a year prior to reproduction.     

Mapping QTL for growth and shank traits in chickens divergently selected for high or low body weight

An F₂ population (695 individuals) was established from broiler chickens divergently selected for either high (HG) or low (LG) growth, and used to localize QTL for developmental changes in body weight (BW), shank length (SL9) and shank diameter (SD9) at 9 weeks. QTL mapping revealed three genome‐wide QTL on chromosomes (GGA) 2, 4 and 26 and three suggestive QTL on GGA 1, 3 and 5. Most of the BW QTL individually explained 2–5% of the phenotypic variance. The BW QTL on GGA2 explained about 7% of BW from 3 to 7 weeks of age, while that on GGA4 explained 15% of BW from 5 to 9 weeks. The BW QTL on GGA2 and GGA4 could be associated with early and late growth respectively. The GGA4 QTL also had the largest effect on SL9 and SD9 and explained 7% and 10% of their phenotypic variances respectively. However, when SL9 and SD9 were corrected with BW9, a shank length percent QTL was identified on GGA2. We identified novel QTL and also confirmed previously identified loci in other chicken populations. As the foundation population was established from commercial broiler strains, it is possible that QTL identified in this study could still be segregating in commercial strains.     

Aromatase gene and its effects on growth, reproductive and maternal ability traits in a multibreed sheep population from Brazil

We determined the polymorphism C242T of the aromatase gene (Cyp19) and its allelic frequency, as well as the effect of the variants on productive and reproductive traits in 71 purebred Santa Inês sheep, 13 purebred Brazilian Somali sheep, nine purebred Poll Dorset sheep, and 18 crossbred 1/2 Dorper sheep. The animals were genotyped using the PCR-RFLP technique. The influence of the animal's genotype on its performance or on the performance of its lambs was analyzed by the least square method. Another factor assessed was the importance of the animal's genotype in analysis models for quantitative breeding value estimates, and whether there were differences among the averages of breeding values of animals with different genotypes for this gene. In the sample studied, no AA individuals were observed; the AB and BB frequencies were 0.64 and 0.36, respectively. All Brazilian Somali sheep were of genotype BB. All 1/2 Dorper BB animals presented a lower age at first lambing, and the Santa Inês BB ewes presented a lower lambing interval. In these same genetic groups, AB ewes presented higher litter weight at weaning. This is evidence that BB ewes have a better reproductive performance phenotype, whereas AB ewes present a better maternal ability phenotype. However, in general, animals with genotype AB presented better average breeding values than those with genotype BB.     

Genetic parameters for growth, reproductive and maternal traits in a multibreed meat sheep population

The genetic parameters for growth, reproductive and maternal traits in a multibreed meat sheep population were estimated by applying the Average Information Restricted Maximum Likelihood method to an animal model. Data from a flock supported by the Programa de Melhoramento Genético de Caprinos e Ovinos de Corte (GENECOC) were used. The traits studied included birth weight (BW), weaning weight (WW), slaughter weight (SW), yearling weight (YW), weight gain from birth to weaning (GBW), weight gain from weaning to slaughter (GWS), weight gain from weaning to yearling (GWY), age at first lambing (AFL), lambing interval (LI), gestation length (GL), lambing date (LD - number of days between the start of breeding season and lambing), litter weight at birth (LWB) and litter weight at weaning (LWW). The direct heritabilities were 0.35, 0.81, 0.65, 0.49, 0.20, 0.15 and 0.39 for BW, WW, SW, YW, GBW, GWS and GWY, respectively, and 0.04, 0.06, 0.10, 0.05, 0.15 and 0.11 for AFL, LI, GL, LD, LWB and LWW, respectively. Positive genetic correlations were observed among body weights. In contrast, there was a negative genetic correlation between GBW and GWS (-0.49) and GBW and GWY (-0.56). Positive genetic correlations were observed between AFL and LI, LI and GL, and LWB and LWW. These results indicate a strong maternal influence in this herd and the presence of sufficient genetic variation to allow mass selection for growth traits. Additive effects were of little importance for reproductive traits, and other strategies are necessary to improve the performance of these animals.     

Life history tactics of darters (Percidae: Etheostomatiini) and their relationship with body size, reproductive behaviour, latitude and rarity

Patterns of covariation of life history traits of darters in the genus Etheostoma are reviewed. The primary pattern is associated with body size. Large darters grow faster, mature at a larger size, produce bigger clutches, and have longer reproductive and life spans, and shorter spawning seasons, than do small darters. When the effects of size are removed statistically, the dominant secondary pattern matched the r-K continuum from fast-growing, short-lived, primarily semelparous species with many small ova and a high reproductive effort (r-species) to slow-growing, long-lived, iteroparous species with few large ova and a low reproductive effort (K-species). Variation in life history traits is also influenced by reproductive behaviour, latitude, and rarity (as measured by geographic range). There are significant differences in the primary and secondary life history patterns among reproductive guilds. Latitude and rarity are not correlated with these primary and secondary patterns. Instead, they account for variation of tertiary patterns. Rare species may not match the reproductive performance of more common and widely distributed species. Future studies of life history traits in darters should focus on species whose reproductive behaviour differs from that of the species reviewed in this study, and on the demographic characteristics of rare or declining populations.     

Relationships of reproductive traits and body size with attainment of sexual maturity and age in Blanding's turtles (Emydoidea blandingi)

To place associations among body size, age at maturity, age, and reproductive traits of a long-lived organism in the context of current life history models based on the concept of norms of reaction, we examined data from a mark-recapture study of Blanding's turtles (Emydoidea blandingi) in southeastern Michigan during 24 of the years between 1953 and 1988. Females matured between 14 and 20 years of age. Both the smallest and largest adult females in the population were reproducing for the first time in their lives. This result suggests that a combination of differences in juvenile growth rates and ages at maturity, and not indeterminate growth, are the primary cause of variation in body size among adults. Body size variation among individuals was not related to age at sexual maturity. Females that had slower growth rates as juveniles matured later at similar mean body size compared to those with more rapid growth that matured at an earlier age. As a result, a linear model of age at sexual maturity with growth rates of primiparous females between hatching and maturity was significant and negative (R² = 0.76). Frequency of reproduction of the largest and smallest females was not significantly different. Clutch size did not vary significantly with age among either primiparous or multiparous females. Clutch sizes of primiparous females and multiparous females were not significantly different. However, older females (>55 years minimum age) reproduced more frequently than did younger females (minimum age <36 y).     

Effect of oral theaflavin administration on body weight,fat, and muscle in healthy subjects: a randomized pilot study

Theaflavins are reddish-colored polyphenols in black tea. To test the efficacy of theaflavin administration on body fat and muscle, we performed a randomized, double-blind, placebo-controlled study and investigated the effect of theaflavins administration on the body composition using of healthy subjects. In this study, 30 male and female Japanese were enrolled and participants were randomly allocated to receive placebo, theaflavin (50 or 100 mg/day), or catechin (400 mg/ml) for 10 weeks. The effects were evaluated using body weight, body fat percentage, subcutaneous fat percentage, and skeletal muscle percentage. Theaflavin administration significantly improved body fat percentage, subcutaneous fat percentage, and skeletal muscle percentage when compared to with the placebo. In contrast, there was no significant difference in all measured outcomes between the catechin and the placebo groups. The results indicate that oral administration of theaflavin had a beneficial effect on body fat and muscle in healthy individuals.     

Dietary effects on body composition, glucose metabolism, and longevity are modulated by skeletal muscle mitochondrial uncoupling in mice

Little is known about how diet and energy metabolism interact in determination of lifespan under ad libitum feeding. From 12 weeks of age until death, male and female wild-type (WT) and transgenic (TG) mice with increased skeletal muscle mitochondrial uncoupling (HSA-mUCP1 mice) were fed one of three different semisynthetic diets differing in macronutrient ratio: control (high-carbohydrate/low-fat-HCLF) and two high-fat diets: high-carbohydrate/high-fat (HCHF), and low-carbohydrate/high-fat (LCHF). Compared to control and LCHF, HCHF feeding rapidly and significantly increased body fat content in WT. Median lifespan of WT was decreased by 33% (HCHF) and 7% (LCHF) compared to HCLF. HCHF significantly increased insulin resistance (HOMA) of WT from 24 weeks on compared to control. TG mice had lower lean body mass and increased energy expenditure, insulin sensitivity, and maximum lifespan (+10%) compared to WT. They showed a delayed development of obesity on HCHF but reached similar maximum adiposity as WT. TG median lifespan was only slightly reduced by HCHF (-7%) and unaffected by LCHF compared to control. Correlation analyses showed that decreased longevity was more strongly linked to a high rate of fat gain than to adiposity itself. Furthermore, insulin resistance was negatively and weight-specific energy expenditure was positively correlated with longevity. We conclude that (i) dietary macronutrient ratios strongly affected obesity development, glucose homeostasis, and longevity, (ii) that skeletal muscle mitochondrial uncoupling alleviated the detrimental effects of high-fat diets, and (iii) that early imbalances in energy homeostasis leading to increased insulin resistance are predictive for a decreased lifespan.     

Identification of chromosomal regions associated with growth and carcass traits in an F3 full sib intercross line originating from a cross of chicken lines divergently selected on body weight

An F₃ resource population originating from a cross between two divergently selected lines for high (D+ line) or low (D− line) body weight at 8-weeks of age (BW55) was generated and used for Quantitative Trait Locus (QTL) mapping. From an initial cross of two founder F₀ animals from D(+) and D(−) lines, progeny were randomly intercrossed over two generations following a full sib intercross line (FSIL) design. One hundred and seventy-five genome-wide polymorphic markers were employed in the DNA pooling and selective genotyping of F₃ to identify markers with significant effects on BW55. Fifty-three markers on GGA2, 5 and 11 were then genotyped in the whole F₃ population of 503 birds, where interval mapping with GridQTL software was employed. Eighteen QTL for body weight, carcass traits and some internal organ weights were identified. On GGA2, a comparison between 2-QTL vs. 1-QTL analysis revealed two separate QTL regions for body, feet, breast muscle and carcass weight. Given co-localization of QTL for some highly correlated traits, we concluded that there were 11 distinct QTL mapped. Four QTL localized to already mapped QTL from other studies, but seven QTL have not been previously reported and are hence novel and unique to our selection line. This study provides a low resolution QTL map for various traits and establishes a genetic resource for future fine-mapping and positional cloning in the advanced FSIL generations.     

Genetic estimates of annual reproductive success in male brown bears: the effects of body size, age, internal relatedness and population density

1. We studied male yearly reproductive success (YRS) and its determinants (phenotypic characteristics, age, population density) in two Scandinavian brown bear populations, using molecular techniques to determine paternity. 2. We found a significant difference in male YRS between the study areas, with lower YRS in the south than in the north. 3. In general, older and larger males had higher YRS. Older males may be more experienced in competition for reproduction (male dominance). Large body size is of direct benefit in male-male competition and of advantage in endurance competition for the access to females. 4. Age was relatively more important for YRS in the north and body size was more important in the south, due perhaps to differences in male age structure due to illegal killing. A single old male dominated the reproduction in the north during the study, which resulted most probably in the relatively higher importance of age in the north. In the south, with a more even male age structure, no single male was able to dominate, probably resulting in a more intense competition among males, with body size as the deciding factor. 5. Male YRS was correlated positively with population density. This may be related to the structure of the expanding bear population, with female densities declining towards the population edge. 6. Internal relatedness, a measure of genetic heterozygosity, was correlated negatively with YRS, suggesting that outbred individuals have a higher YRS. Individual heterozygosity at key or many loci may reflect male physical qualities and condition-sensitive traits, which may benefit males directly in contest or in sperm competition.     

Variations in body length, weight, fat content and survival inCoccinella septempunctata at different hibernation sites

Adults ofCoccinella septempunctata L. (Coleoptera; Coccinellidae) were sampled in four overwintering sites: one in England and three at different altitudes in the Czech Republic (350–1420 m above sea level) in autumn 1992 and spring 1993. Body length, dry weight and fat weight were measured. There were significant differences in body length between sampling sites in spring 1993, but not in autumn 1992. The average sex ratio (♀) in all samples was 1∶0.60 in 1992 and 1∶0.72 in 1993. Females were significantly larger and heavier, and contained more fat than males in both sampling periods. Dry weight and fat weight were positively correlated to body length at all sampling sites except at Ruzyne, in the Czech Republic. Adults hibernating at higher altitudes and away from their breeding and feeding habitats had significantly more fat than those hibernating at lower altitudes. Fat reserves were reduced by 30% during the hibernation at the top of the Krkonose mountain, in the Czech Republic, where temperatures were much lower, but more than half of the fat reserves were consumed during the overwintering period at the other sampling sites. The significance of body length and fat reserves in relation to adult hibernation sites and overwintering survival is discussed.     

Consequences of adult size for survival and reproductive performance in a herbivorous ladybird beetle

Abstract.

• 1 A univoltine herbivorous ladybird beetle Epilachna niponica (Coleoptera: Coccinellidae) shows a large variation in adult size within a population.
• 2 Large adults had higher survival from emergence to the reproductive season, and the size-dependent adult survival was most apparent during hibernation. On the other hand, adult survival during pre-hibernation contributed little to size-dependent overall survival.
• 3 Neither reproductive lifespan nor lifetime fecundity were a function of adult size, though large females produced larger size of egg batches.
• 4 Size of adult beetles was significantly reduced by leaf damage to plants on which they grew up on larval stage. Since leaf herbivory increases through the season, late emerged adults that were subjected to food deterioration during the larval period were smaller than early-emerged individuals.

     

Male reproductive success and its behavioural correlates in a polygynous mammal,the Galápagos sea lion (Zalophus wollebaeki)

Sexual selection theory predicts competitive males and choosy females. Nevertheless, since molecular marker‐based studies, paternity outside the expected mating patterns has increasingly been described. Even in highly polygynous systems, where paternity is expected to be strongly skewed towards large, dominant males, alternative mating tactics have been suggested. We examined reproductive success in the polygynous Galápagos sea lion (Zalophus wollebaeki). Semiaquatic territoriality allows females to move freely and may lower the degree of polygyny otherwise suggested by both territorial behaviour and strong sexual dimorphism. We assigned paternities with 22 microsatellites and analysed how male reproductive success was related to size, dominance status, intra‐sexual agonistic behaviour, proximity to females, and attendance in the colony. Male behaviour was consistent across two seasons for all parameters under consideration. Attendance was by far the most important determinant of paternal success. Skew in reproductive success towards large, dominant males was weak and dominance status played no role. This appears to be caused by an extremely long reproductive season lasting five or more months, making it difficult for any male to monopolize receptive females. Females seem to choose displaying males that were present in the colony for a long time rather than dominance per se. Sexual dimorphism in Galápagos sea lions may thus be more influenced by selection for fasting than fighting ability. Our data provide further evidence for alternative mating tactics, as several males gained relatively high reproductive success despite short attendance and hardly any involvement in agonistic interactions.     

Timing of eclosion affects diapause development, fat body consumption and longevity in Osmia lignaria, a univoltine, adult-wintering solitary bee

Most insects from temperate areas enter diapause ahead of winter. Species diapausing in a feeding stage and accumulating metabolic reserves during permissive pre-wintering conditions are expected to enter diapause shortly before the onset of winter. In contrast, species diapausing in a non-feeding stage are expected to lower their metabolism as soon as possible to avoid excessive consumption of metabolic reserves. The solitary bee Osmia lignaria winters as a non-feeding adult within its cocoon, but previous studies show important weight losses and increased winter mortality in populations pre-wintered for extended periods. We measured respiration rates to assess diapause initiation and maintenance during pre-wintering, and tested whether timing of adult eclosion affected fitness by measuring fat body depletion, winter mortality and post-winter longevity. We worked with different cohorts of a population reared under natural conditions, and manipulated pre-wintering duration in a population reared under artificial conditions. In agreement with our expectation, O. lignaria lower their metabolic rates within a few days of adult eclosion, but nonetheless suffer strong weight loss during pre-wintering. Early developing individuals suffer greater weight loss and fat body depletion, and have short post-winter longevity. Although, we found no differences in winter mortality among treatments, our results indicate that increased mortality may occur in years with late winter arrivals. We discuss fundamental ecophysiological differences between adult and prepupal diapause within the Megachilidae, and hypothesize that species wintering as adults will be more negatively affected by a situation of extended summers under a scenario of global warming.     

Age-specific flight behavior in relation to body weight and lipid content of Ips calligraphus reared in slash pine bolts with thick or thin inner bark (phloem)

Rearing larvae of Ips calligraphus (Germar) (Coleoptera: Scolytidae) in bolts of typical slash pine, Pinus elliottii Engelm. var. elliottii, with thin (TN; 0.5–1.5 mm) phloem (inner bark) relative to adult beetle body width significantly reduced body weight and lipid content of emerging adults compared with thick (TK; 2.5–3.5 mm) phloem-reared adults. Unmated (pre-nuptial) TK beetles averaged 2-fold longer daily and life-time flight duration than TN beetles. Daily flights were highly variable, averaging <20 min (longest daily flight=173 min). TK and TN beetles initiated flight, and the greatest number flew, on the first or second day after emergence form their rearing bolt; % of beetles flying and survival gradually declined to zero by day 9. Males (both TK and TN) averaged 2.5 days of flight, ca. 1 day longer than females. Fliers lived ca. 2-fold longer than non-fliers. Among TK and TN fliers, significant but weak positive correlations occurred between body weight and lifetime flight duration. Poor correlation between lifetime flight duration and longevity suggests little physiological cost to flight, but effects on fecundity were not assessed. Flight by mated, egg-laying (post-nuptial) beetles was substantially delayed (peaking on day 6), suggesting degeneration and subsequent regeneration of flight muscles.

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Résumé Le comportement de vol d'Ips calligraphus GERMAR (Scolytidae) a été examiné au laboratoire par une technique de vol captif. La génération parentale avait été artificiellement introduite, suivant la taille des adultes (1,6 à 2,1 mm) dans des morceaux de Pinus elliottii Engelm. variété elliottii au phloeme épais (TK=2,5 à 3,5 mm) ou fin (TN=0,5 à 1,5 mm) les larves se sont développées dans ces morceaux de pin. Le poids et la teneur en lipide des adultes obtenus à partir de TN étaient significativement inférieure à ceux de TK. Le poids des mâles les plus gros a été plus réduit que celui des femelles; les mâles les plus petits semblaient être moins efficaces dans l'initiation des attaques sur les arbres, et les femelles les plus petites ont eu une fécondité réduite.Les durées de vol quotidiennes pendant la vie des mâles TK vierges étaient en moyenne deux fois plus longues que celles des mâles TN. Les durées de vol quotidiennes étaient très variables: en moyenne moins de 20 minutes, mais la plus longue a été de 173 mn. En moyennes les adultes TN et TK ont commencé à voler, et volaient en plus grand nombre, le premier et le second jour après l'émergence. Ensuite la fréquence d'adultes volants et le pourcentage de surviveants, ont graduellement diminué jusqu'à tomber à zéro le neuvième jour. Les mâles TN et TK avaient des vols quotidiens plus longs et volaient environ 1 jour de plus que les femelles. L'activité de vol accrue des mâles reflète leur besoin de trouver dans la nature des arbres convenables; les vols des femelles peuvent généralement être plus brefs, étant plus directement orientés comme une réponse aux phéromones mâles.Les voiliers ont vécu environ 2 fois plus longtemps que les non-voiliers. Parmi les voiliers TK et TN il y avait une corrélation positive étroite entre le poids du corps et la durée totale des vols. Il n'y en a qu'une faible corrélation entre cette durée totale des vols et la longévité, suggérant un faible coût physiologique du vol. L'influence de cette durée des vols et du prélèvement consécutif de lipides sur la fécondité n'a pas été examinée. L'initiation au vol chez les individus fécondés a été sérieusement retardée (maximum le sixième jour) par rapport aux vierges, ce qui suggère un dégénérescence des muscles du vol associée à la reproduction, suivie d'une régénération importante, comme cela a été signalé chez d'autres Scolytes.Ces résultats contribuent à notre compréhension des facteurs conditionnant le comportement de vol et d'autres aspects fondamentaux de la biologie des insectes des pins. Une telle connaissance est nécessaire au développement d'une politique efficace de protection.

     

Polymorphisms on SSC15q21-q26 Containing QTL for reproduction in Swine and its association with litter size

Several quantitative trait loci (QTL) for important reproductive traits (ovulation rate) have been identified on the porcine chromosome 15 (SSC15). To assist in the selection of positional candidate swine genes for these QTL on SSC15, twenty-one genes had already been assigned to SSC15 in a previous study in our lab, by using the radiation hybrid panel IMpRH. Further polymorphism studies were carried out on these positional candidate genes with four breeds of pigs (Duroc, Erhualian, Dahuabai and Landrace) harboring significant differences in reproduction traits. A total of nineteen polymorphisms were found in 21 genes. Among these, seven in six genes were used for association studies, whereby NRP2 polymorphism was found to be significantly (p < 0.05) associated with litter-size traits. NRP2 might be a candidate gene for pig-litter size based on its chromosome location (Du et al., 2006), significant association with litter-size traits and relationships with Sema and the VEGF super families.     

Survival, longevity and fecundity of overwintering Mesoplatys ochroptera Stål (Coleoptera: Chrysomelidae) defoliating Sesbania sesban (Leguminosae) and implications for its management in southern Africa

1 The defoliator beetle, Mesoplatys ochroptera Stål, is a serious pest of the legume tree sesbania (Sesbania sesban (L.) Merrill) in agroforestry systems in southern Africa. The survival of the overwintering stage of M. ochroptera and post‐ emergence longevity and fecundity of adults in sesbania fallows in eastern Zambia were quantified. 2 Only adult M. ochroptera survived during the winter (May–August) and the dry season (September–October) hidden under weeds, plant litter, in soil cracks and under rocks. During these periods, some beetles were occasionally found feeding on S. sesban, particularly in natural stands in humid areas. The adults were parasitized by the braconid Perilitus larvicida van Achterberg at a rate of 8.5–16.4%. The beetles stayed in the winter refuges for up to 210 days and emerged with the first heavy rains in October–November. The effective survival of beetles overwintering in an insectary was 18.1% in 1998 and 37.7% in 1999, and that of beetles overwintering in the field was estimated at 0.4 and 2.8% in 1998 and 1999, respectively. 3 The post‐emergence longevity and oviposition period of females in the insectary was 14–31 days and 5–29 days, respectively. The post‐emergence fecundity varied from 87 to 783. 4 It is concluded that the serious M. ochroptera infestation observed every year following the rains is due to synchronous emergence of overwintered resident adult populations and their high capacity for reproduction on many species of Sesbania. Recommendations for pest management in sesbania planted‐fallows are given.