scholarly journals Behavioral and physiological flexibility are used by birds to manage energy and support investment in the early stages of reproduction

2010 ◽  
Vol 56 (6) ◽  
pp. 767-792 ◽  
Author(s):  
François Vézina ◽  
Katrina G. Salvante
Keyword(s):  
Egg Production ◽  
Egg Size ◽  
Behavioral Flexibility ◽  
Reproductive Investment ◽  
Tissue Remodeling ◽  
Reproductive Organs ◽  
Energy Budgets ◽  
Phenotypic Flexibility ◽  
Zebra Finches ◽  
Daily Energy

Abstract Interest in phenotypic flexibility has increased dramatically over the last decade, but flexibility during reproduction has received relatively little attention from avian scientists, despite its possible impact on fitness. Because most avian species maintain atrophied reproductive organs when not active, reproduction in birds requires major tissue remodeling in preparation for breeding. Females undergo rapid (days) recrudescence and regression of their reproductive organs at each breeding attempt, while males grow their organs ahead of time at a much slower rate (weeks) and may maintain them at maximal size throughout the breeding season. Reproduction is associated with significant metabolic costs. Egg production leads to a 22%-27% increase in resting metabolic rate (RMR) over non-reproductive values. This is partly due to the activity of the oviduct, an organ that may allow females to adjust reproductive investment by modulating egg size and quality. In males, gonadal recrudescence may lead to a 30% increase in RMR, but the data are inconsistent and general conclusions regarding energetic costs of reproduction in males will require more research. Recent studies on captive female zebra finches describe the impacts of these costs on daily energy budgets and highlight the strategies used by birds to maintain their investment in reproduction when energy is limited. Whenever possible, birds use behavioral flexibility as a first means of saving energy. Decreasing locomotor activity saves energy during challenges such as egg production or exposure to cold temperatures and is an efficient way to buffer variation in individual daily energy budgets. However, when behavioral flexibility is not possible, birds must rely on flexibility at the physiological level to meet energy demands. In zebra finches breeding in the cold, this results in a reduced pace of laying, likely due to down-regulation of both reproductive and non-reproductive function, allowing females to defend minimal egg size and maintain reproductive success. More research involving a range of species in captive and free-living conditions is needed to determine how phenotypic flexibility during tissue remodeling and early reproductive investment translates to natural conditions and affects fitness.

Do Female Zebra Finches Vary Primary Reproductive Effort in Relation to Mate Attractiveness?

Behaviour ◽  
1998 ◽  
Vol 135 (3) ◽  
pp. 297-309 ◽  
Author(s):  
Alison Balzer ◽  
Tony Williams
Keyword(s):  
Egg Production ◽  
Egg Size ◽  
Reproductive Effort ◽  
Egg Quality ◽  
Male Partner ◽  
Zebra Finches ◽  
Mate Quality ◽  
Significant Difference ◽  
Song Frequency ◽  
Breeding Propensity

AbstractFemale choice and mate preference have been shown to affect female reproductive effort both prior to copulation (e.g. females seeking extra-pair copulation) and during parental care ('secondary' reproductive effort) in relation to mate quality. Here we show that female zebra finches, Taeniopygia guttata, vary their 'primary' reproductive effort in egg production in relation to the attractiveness of their male partner, for some components of reproduction but not others. Females were allowed to choose 'preferred' and 'non-preferred' males in standard mate choice trials, and were then paired sequentially with each male. Preferred males had significantly higher song duration and song frequency than non-preferred males confirming that females preferred attractive, higher quality males. Male attractiveness had a positive, but weak, effect on clutch size: in breeding experiments individual females laid on average 0.5 eggs more when paired with their preferred male compared to the non-preferred male. However, there was no significant difference in breeding propensity (whether females laid eggs or not), number of days between pairing and laying, mean egg size or egg quality (protein and lipid composition) in relation to male type. These results suggest that components of primary reproductive effort in individual female zebra finches are relatively non-plastic traits.

scholarly journals Adult body growth and reproductive investment vary markedly within and across Atlantic and Pacific herring: a meta-analysis and review of 26 stocks

2021 ◽  
Author(s):  
Thassya C. dos Santos Schmidt ◽  
Doug E. Hay ◽  
Svein Sundby ◽  
Jennifer A. Devine ◽  
Guðmundur J. Óskarsson ◽  
...  
Keyword(s):  
Egg Size ◽  
Meta Analysis ◽  
Reproductive Investment ◽  
Body Growth ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Atlantic Herring ◽  
Additional Information ◽  
Trade Offs ◽  
Investment In Reproduction

AbstractLife-history traits of Pacific (Clupea pallasii) and Atlantic (Clupea harengus) herring, comprising both local and oceanic stocks subdivided into summer-autumn and spring spawners, were extensively reviewed. The main parameters investigated were body growth, condition, and reproductive investment. Body size of Pacific herring increased with increasing latitude. This pattern was inconsistent for Atlantic herring. Pacific and local Norwegian herring showed comparable body conditions, whereas oceanic Atlantic herring generally appeared stouter. Among Atlantic herring, summer and autumn spawners produced many small eggs compared to spring spawners, which had fewer but larger eggs—findings agreeing with statements given several decades ago. The 26 herring stocks we analysed, when combined across distant waters, showed clear evidence of a trade-off between fecundity and egg size. The size-specific individual variation, often ignored, was substantial. Additional information on biometrics clarified that oceanic stocks were generally larger and had longer life spans than local herring stocks, probably related to their longer feeding migrations. Body condition was only weakly, positively related to assumingly in situ annual temperatures (0–30 m depth). Contrarily, body growth (cm × y−1), taken as an integrator of ambient environmental conditions, closely reflected the extent of investment in reproduction. Overall, Pacific and local Norwegian herring tended to cluster based on morphometric and reproductive features, whereas oceanic Atlantic herring clustered separately. Our work underlines that herring stocks are uniquely adapted to their habitats in terms of trade-offs between fecundity and egg size whereas reproductive investment mimics the productivity of the water in question.

scholarly journals Mode of action evaluation for reduced reproduction in Daphnia pulex exposed to the insensitive munition, 1-methyl-3-nitro-1-nitroguanidine (MeNQ)

Ecotoxicology ◽  
2021 ◽  
Author(s):  
Kurt A. Gust ◽  
Guilherme R. Lotufo ◽  
Natalie D. Barker ◽  
Qing Ji ◽  
Lauren K. May
Keyword(s):  
Egg Production ◽  
Daphnia Pulex ◽  
Indirect Costs ◽  
Energy Budgets ◽  
Exposure Level ◽  
Transcriptional Expression ◽  
Canonical Pathways ◽  
Significant Enrichment ◽  
Inducible Protein ◽  
Reproductive Processes

AbstractThe US Department of Defense (DOD) is developing insensitive munitions (IMs) that are resistant to unintended detonation to protect warfighters. To enable material life-cycle analysis for the IM, 1-methyl-3-nitro-1-nitroguanidine (MeNQ), ecotoxicological impacts assessment was required. A previous investigation of MeNQ exposures in Daphnia pulex revealed concentration-responsive decreases in reproduction relative to controls (0 mg/L) across a 174, 346, 709, 1385, and 2286 mg/L exposure range. The present study used those exposures to conduct global transcriptomic expression analyses to establish hypothetical mode(s) of action underlying inhibited reproduction. The number of significantly affected transcripts and the magnitude of fold-change differences relative to controls tended to increase with increasing MeNQ concentration where hierarchical clustering analysis identified separation among the “low” (174 and 346 mg/L) and “high” (709, 1385, and 2286 mg/L) exposures. Vitellogenin is critical to Daphnia reproductive processes and MeNQ exposures significantly decreased transcriptional expression for vitellogenin-1 precursor at the lowest exposure level (174 mg/L) with benchmark dose (BMD) levels closely tracking concentrations that caused inhibited reproduction. Additionally, juvenile hormone-inducible protein, chorion peroxidase, and high choriolytic enzyme transcriptional expression were impacted by MeNQ exposure having potential implications for egg production / maturation and overall fecundity. In concert with these effects on specific genes involved in Daphnia reproductive physiology, MeNQ exposures caused significant enrichment of several canonical-pathways responsible for metabolism of cellular energy substrates where BMD levels for transcriptional expression were observed at ≤100 mg/L. These observations imply possible effects on whole-organism energy budgets that may also incur indirect costs on reproduction.

Effects of constant and fluctuating temperatures on egg production in the threespine stickleback (Gasterosteus aculeatus)

1989 ◽  
Vol 67 (6) ◽  
pp. 1599-1602 ◽  
Author(s):  
Vital Boulé ◽  
Gerard J. Fitzgerald
Keyword(s):  
Reproductive Performance ◽  
Egg Production ◽  
Egg Size ◽  
Laboratory Experiments ◽  
Gasterosteus Aculeatus ◽  
Reproduction Number ◽  
Temperature Fluctuations ◽  
Spawning Grounds ◽  
Threespine Sticklebacks ◽  
Fluctuating Temperatures

Female threespine sticklebacks (Gasterosteus aculeatus) spend only 9–15 days on the spawning grounds, an intertidal salt marsh at Isle Verte, Quebec, during a 2-month breeding season. Individuals average only one spawning. However, in the laboratory they lay clutches of several hundred eggs every 3–5 days for several months. We designed laboratory experiments to determine (i) whether daily temperature fluctuations similar to those encountered in the marsh affect reproduction (number of clutches, number of eggs per clutch, and size of eggs) and (ii) whether the amplitude of the fluctuations encountered by the fish affects reproduction. We compared the reproduction of females held in fluctuating temperatures with that of females kept at 20 °C. Fish kept under fluctuating conditions produced more eggs per clutch but had longer interspawning intervals than those at 20 °C. Total seasonal egg production and egg size did not differ between the two groups. Fish in fluctuating temperatures survived longer and were in better condition than those at 20 °C. We conclude that the amplitude of the fluctuations is less important than mean temperature in determining reproductive performance. Fluctuating temperatures on the spawning grounds are not responsible for the short residency there.

Flexible energetics of cheetah hunting strategies provide resistance against kleptoparasitism

Science ◽  
2014 ◽  
Vol 346 (6205) ◽  
pp. 79-81 ◽  
Author(s):  
David M. Scantlebury ◽  
Michael G. L. Mills ◽  
Rory P. Wilson ◽  
John W. Wilson ◽  
Margaret E. J. Mills ◽  
...  
Keyword(s):  
Population Viability ◽  
Energy Budgets ◽  
Hunting Strategies ◽  
Direct Competition ◽  
Daily Energy ◽  
Balancing Energy ◽  
Individual Survival ◽  
Power Outputs ◽  
Wild Dogs ◽  
Increased Activity

Population viability is driven by individual survival, which in turn depends on individuals balancing energy budgets. As carnivores may function close to maximum sustained power outputs, decreased food availability or increased activity may render some populations energetically vulnerable. Prey theft may compromise energetic budgets of mesopredators, such as cheetahs and wild dogs, which are susceptible to competition from larger carnivores. We show that daily energy expenditure (DEE) of cheetahs was similar to size-based predictions and positively related to distance traveled. Theft at 25% only requires cheetahs to hunt for an extra 1.1 hour per day, increasing DEE by just 12%. Therefore, not all mesopredators are energetically constrained by direct competition. Other factors that increase DEE, such as those that increase travel, may be more important for population viability.

RESPONSE OF LAYING HENS TO GRADED LEVELS OF DIETARY NUTRAFOS 3 IN A HUMID TROPICAL ENVIRONMENT

2021 ◽  
Vol 15 ◽  
pp. 185-196
Author(s):  
M. MONSI ◽  
A. O. AMAKIRI
Keyword(s):  
Treatment Effect ◽  
Feed Efficiency ◽  
Egg Production ◽  
Egg Size ◽  
Laying Hens ◽  
Gallus Domesticus ◽  
Feed Consumption ◽  
Tropical Conditions ◽  
Overall Performance ◽  
Haugh Unit

Four groups of 48 laying hens (Gallus domesticus), midway in their laying cycle were fed diets containing graded levels (0.00%, 1.5%, 2.5% and 3.5%) of dietary Nutrafos 3 for 56 days. The completely randomized experimental arrangement was designed to evaluate the responses of the caged layers to the inclusive levels of the additive under humid tropical conditions. The dietary additive produced statistically significant (P< 0.01) improvements in the rate of egg production of the hens. Significant increases (P< 0.01) in feed consumption and improvements in feed efficiency (P < 0.01) were also observed. Haugh unit was significantly (P < 0.05) depressed by dietary Nutrafos 3, especially at the highest level of inclusion. There was no treatment effect on egg size as well as some major anatomical characteristics. The best overall performance was achieved at the 3.5% level of dietary inclusion in contrast to the proprietary recommendation of 2.5%.

STUDIES ON THE USE OF FABA BEANS IN RATIONS FOR LAYING HENS

1977 ◽  
Vol 57 (3) ◽  
pp. 421-425 ◽  
Author(s):  
A. R. ROBBLEE ◽  
D. R. CLANDININ ◽  
R. T. HARDIN ◽  
G. R. MILNE ◽  
K. DARLINGTON
Keyword(s):  
Egg Production ◽  
Egg Size ◽  
Production Efficiency ◽  
White Leghorn ◽  
Feed Conversion ◽  
Considerable Decrease ◽  
Large Size ◽  
Vicia Faba L ◽  
Faba Beans

In two experiments, White Leghorn pullets kept in batteries were fed rations containing 0, 5, 10, 15, 20 or 30% raw faba beans (Vicia faba L.) for 336 days. The rations were designed to be isocaloric, isonitrogenous and to have equal levels of methionine plus cystine. The results obtained indicated that levels up to and including 20% faba beans in ration ssupplemented with methionine had no adverse effect on mortality, rate of egg production, efficiency of feed conversion or body weight. A level of 30% faba beans resulted in increased mortality, and decreased egg production and feed conversion in one experiment but had no effect in the other. Egg size tended to decrease as the level of faba beans in the ration increased, resulting in a considerable decrease in the percentage of "large size" eggs graded according to Canadian standards. There was an increase in interior quality of the eggs as measured by Haugh units as the level of faba beans used increased. Specific gravity of the eggs was not affected by use of faba beans in the rations.

Reproductive performance in a phyletic dwarf, the spider crab Petramithrax pygmaeus (Bell, 1836) (Decapoda: Brachyura: Mithracidae)

2020 ◽  
Vol 40 (3) ◽  
pp. 325-329
Author(s):  
Joshua T Fields ◽  
Hayden K Mullen ◽  
Clayr M Kroenke ◽  
Kyla A Salomon ◽  
Abby J Craft ◽  
...  
Keyword(s):  
Body Size ◽  
Reproductive Performance ◽  
Related Species ◽  
Egg Production ◽  
Marine Invertebrates ◽  
Small Body ◽  
Reproductive Investment ◽  
Spider Crab ◽  
Closely Related Species ◽  
Body Sizes

Abstract The spider crab Petramithrax pygmaeus (Bell, 1836), a phyletic dwarf, was used to test predictions regarding reproductive performance in small marine invertebrates. Considering the disproportional increase in brooding costs and the allometry of egg production with increasing body size, it was expected that this minute-size species would produce large broods compared to closely related species that attain much larger body sizes. Fecundity in P. pygmaeus females carrying early and late eggs varied, respectively, between 17 and 172 eggs crab–1 (mean ± SD = 87.97 ± 48.39) and between 13 and 159 eggs crab–1 (55.04 ± 40.29). Females did not experience brood loss during egg development. Egg volume in females carrying early and late eggs varied, respectively, between 0.13 and 0.40 mm3 (0.22 ± 0.07) and between 0.15 and 0.42 mm3 (0.26 ± 0.06 mm3). Reproductive output (RO) varied between 0.91 and 8.73% (3.81 ± 2.17%) of female dry body weight. The RO of P. pygmaeus was lower than that reported for closely related species with larger body sizes. The slope (b = 0.95 ± 0.15) of the line describing the relationship between brood and parental female dry weight was not statistically significant from unity. Overall, our results disagree with the notion that the allometry of gamete production and increased physiological costs with increased brood size explain the association between brooding and small body size in marine invertebrates. Comparative studies on the reproductive investment of brooding species belonging to monophyletic clades with extensive differences in body size are warranted to further our understanding about disparity in egg production in brooding marine invertebrates.

Winter energy expenditure and the distribution of southern flying squirrels

1991 ◽  
Vol 69 (10) ◽  
pp. 2548-2555 ◽  
Author(s):  
Paul Stapp ◽  
Peter J. Pekins ◽  
William W. Mautz
Keyword(s):  
Energy Expenditure ◽  
Heat Loss ◽  
Current Distribution ◽  
Basal Metabolism ◽  
Energy Budgets ◽  
Late Winter ◽  
Daily Energy Expenditure ◽  
Flying Squirrels ◽  
Tree Cavities ◽  
Daily Energy

The southern flying squirrel (Glaucomys volans) forms large aggregations inside nest-lined tree cavities to reduce exposure to winter temperatures. We measured oxygen consumption of individuals and grouped flying squirrels in Plexiglas and nest-box chambers in New Hampshire to determine savings provided by huddling and nest construction. Because G. volans breeds during late winter, we also measured energy expenditure of females during gestation and lactation. These data were used to construct daily energy budgets for flying squirrels during winter and to investigate the relationship between this species' cold tolerance and its current distribution. Flying squirrels had lower basal metabolism (0.95 cm3 O2∙g−1∙h−1) and rate of heat loss (0.11 cm3 O2∙g−1∙h−1∙ °C−1) than predicted according to mass. Peak reproductive costs (1 week postparturition) were 170% of nonbreeding requirements. At 9 °C, huddling in groups of three and six reduced energy expenditure by 27 and 36%, respectively. Compared with individuals without nests, nest insulation decreased heat loss by 37% for single squirrels and reduced lower critical temperature from 26.5 to 12.2 °C for groups of six. As estimated from our budget, aggregating reduces winter daily energy expenditure by 26–33%. At the northern range boundary, daily expenditure for squirrels using both aggregations and nests (2.5 times basal metabolism) and for females during peak lactation (3.9 times basal metabolism) was similar to estimates of maximal daily energy expenditure in the literature. We speculate that additional thermoregulatory costs and the decreased abundance of hard mast for winter caches prevent G. volans from occupying areas north of its current distribution.

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