Relationship between nest defence behaviours and reproductive benefits in Chinese alligators

2015 ◽  
Vol 36 (2) ◽  
pp. 141-147 ◽  
Author(s):  
Fang Zhang ◽  
Kevin Messenger ◽  
Yong Wang
Keyword(s):  
Reproductive Success ◽  
Parental Care ◽  
Clutch Size ◽  
Evolutionary Theory ◽  
Fertility Rate ◽  
Nest Defence ◽  
Hatching Rate ◽  
Fertility Rates ◽  
The Relationship ◽  
Hatching Rates

The evolutionary theory in parental care predicts that parents may defend more vigorously of nests with higher survival and reproductive benefits. Based on this prediction, we proposed that the occurrence of nest defence behaviours in Chinese alligators might be connected to reproductive benefits (clutch size, fertility rate, and hatching rate). In this study, we examined the relationship between the occurrence of nest defence behaviours and (1) the variations in clutch size, fertility rate, and hatching rate of wild Chinese alligators, and (2) the variations in clutch size and fertility rate of captive Chinese alligators in a semi-natural facility. Results showed that for the wild Chinese alligators, the fertility and hatching rates with nest defence behaviours were higher than those without nest defence behaviours. The results also showed that for the captive Chinese alligators, the fertility rates with nest defence behaviours were higher than those without nest defence behaviours. These results suggested that nest defence behaviours in Chinese alligators might be relative to reproductive benefits, thus likely to further improve the probability of the species’ reproductive success.

Observations on the relationship between riboflavin, hatchability and clubbed down

1955 ◽  
Vol 46 (2) ◽  
pp. 191-198 ◽  
Author(s):  
R. Coles ◽  
F. Cumber
Keyword(s):  
Conclusive Evidence ◽  
National Average ◽  
Hatching Rate ◽  
Breeding Stock ◽  
High Level ◽  
The Relationship ◽  
Very High ◽  
Average Figure ◽  
Small Improvement ◽  
Hatching Rates

A brief account is given of the accepted view that riboflavin supplements in the diet of breeding stock lead to improved hatchability and that clubbed down is specific for a deficiency of this vitamin. Attention, however, is drawn to the apparent failure of various workers to achieve a hatching rate with a riboflavin supplemented diet substantially in excess of 80% of fertile eggs which appears to be the national average figure. An experiment is described in which range managed breeding stock received diets supplemented with riboflavin at varying levels, the lowest of which, in the light of available evidence, would be sufficient for good hatchability having regard to the riboflavin obtained by the stock from grass and their own droppings. The hatching rate of fertile eggs was maintained at about 80% with all rations and little change took place consequent on changing over from high to low or vice versa. Only a very small improvement was observed with a very high level of riboflavin. It is therefore concluded that either a figure around 80% hatchability represents the maximum influence of riboflavin on hatching rates or that there are generally other factor(s) present (or absent) in the embryo that prevent a higher rate being achieved. The evidence submitted suggests that this factor may be B12 or more probably, one of the unidentified factors in the A.P.F. complex, and that for hatching rates materially above 80% the A.P.F. complex must be increased above the levels presently supplied to range managed breeding stock, or the high hatching rates induced by high levels of riboflavin may greatly increase the birds' requirements for this factor(s) to a level well above that normally necessary.Attention is also drawn to the incidence of clubbed down among dead-in-shell with varying levels of dietary riboflavin. It is concluded that the presence of this embryonic abnormality is rapidly and almost completely influenced by changes in the level of dietary riboflavin and that these changes take place much more rapidly than changes in hatchability, once a moderately high hatching rate has already been reached. It is also contended that high riboflavin levels will almost eliminate the incidence of clubbed down, although an already moderately high hatching rate will remain unaffected. For this reason it is argued that the presence of clubbed down in some dead-in-shell is no conclusive evidence that an improvement in hatchability will follow supplementation of the diet with riboflavin unless the hatching rate is below average.

The influence of microtines on polygyny, productivity, age, and provisioning of breeding Northern Harriers: a 5-year study

1986 ◽  
Vol 64 (11) ◽  
pp. 2447-2456 ◽  
Author(s):  
Robert Simmons ◽  
Phoebe Barnard ◽  
Bruce MacWhirter ◽  
Gay L. Hansen
Keyword(s):  
Reproductive Success ◽  
New Brunswick ◽  
Clutch Size ◽  
Nest Predation ◽  
Strong Relationship ◽  
Prey Abundance ◽  
Nest Defence ◽  
Young Females ◽  
Circus Cyaneus ◽  
The Difference

Breeding Northern Harriers, Circus cyaneus, and their principle prey, the vole Microtus pennsylvanicus, underwent synchronous fluctuations in New Brunswick between 1980 and 1984. Microtines were abundant in 1980 and 1983 and were significantly tracked by the number of nesting harriers (r = 0.90), the number of polygynous males (r = 0.89), the number of harem females (r = 0.90), and the mean clutch size (r = 0.94), but not the reproductive success of successful females (r = 0.72). Male nest defence likewise exhibited a strong relationship (r = 0.99, n = 3) with prey abundance, but nest predation did not. An unexpected association with prey abundance was the greater proportion of young females (≤ 2 years) breeding at vole lows; the reverse was true for yearling males. Young females that did breed at vole highs were significantly more productive than were old females breeding at highs. The difference arose principally through nest predation. Successful females also consistently reared significantly greater proportions of their hatchlings when voles were increasing than when they were decreasing. Our results suggest that New Brunswick harriers were affected by prey fluctuations in most aspects of their reproduction and population dynamics. Significant correlations between male food provisioning rates and clutch size and reproductive success over 3 years provide a proximate mechanism through which fecundity may vary annually. They may also provide a proximate pathway mediating for polygyny.

Brood size manipulation reveals cost on the size of the second clutch in the earwig Anisolabis maritime

Behaviour ◽  
2021 ◽  
pp. 1-11
Author(s):  
Seizi Suzuki
Keyword(s):  
Reproductive Success ◽  
Parental Care ◽  
Clutch Size ◽  
Maternal Care ◽  
Brood Size ◽  
Trade Off ◽  
Brood Size Manipulation ◽  
Second Clutch ◽  
The Cost

Abstract There may be a trade-off between the duration of parental care and future reproductive success. Traditionally, studies about the cost of parental care have included the removal of the parent. However, producing a secondary clutch after the failure of the first one is a compensatory behaviour that occurs in cases of brood failure. In this study, attempts were made to detect the cost of maternal care in the earwig, Anisolabis maritima (Dermaptera: Anisolabididae) by either extending the period of care or increasing the brood size to prevent compensation through the brood’s success. The results indicated that manipulation did not change the inter-clutch interval, although my previous study revealed shortening of these intervals after the removal of the clutch in this species. In this study, decreased clutch size manipulation increased the size of the following clutch.

scholarly journals Reproductive Success and Survival in Relation to Experience During the First Two Years in Canada Geese

The Condor ◽  
2000 ◽  
Vol 102 (4) ◽  
pp. 941-945 ◽  
Author(s):  
Dennis G. Raveling ◽  
James S. Sedinger ◽  
Devin S. Johnson
Keyword(s):  
Reproductive Success ◽  
Parental Care ◽  
Social Organization ◽  
Sexual Maturity ◽  
Family Members ◽  
Branta Canadensis ◽  
Canada Geese ◽  
Family Associations ◽  
The Relationship

Abstract We studied the relationship between family associations of immature Canada Geese (Branta canadensis) and their reproductive success as 2-year-olds and survival to three years. A higher proportion of immature Canada Geese associated with family members survived to breeding age and were more successful in reproducing in their first potential year of sexual maturity (age 2) than were geese that were not in family associations. These results illustrate the benefits of prolonged parental care outweighing costs to parents and the probable influence of family association on future successful breeding. Many reproductive failures of vertebrates with complex social organization may be related to experience during maturation.

scholarly journals The bright incubate at night: sexual dichromatism and adaptive incubation division in an open-nesting shorebird

2015 ◽  
Vol 282 (1806) ◽  
pp. 20143026 ◽  
Author(s):  
Kasun B. Ekanayake ◽  
Michael A. Weston ◽  
Dale G. Nimmo ◽  
Grainne S. Maguire ◽  
John A. Endler ◽  
...  
Keyword(s):  
High Risk ◽  
Reproductive Success ◽  
Parental Care ◽  
Selective Advantage ◽  
Nest Defence ◽  
Sexual Dichromatism ◽  
Parental Roles ◽  
Female Ornamentation ◽  
Care Patterns ◽  
Per Se

Ornamentation of parents poses a high risk for offspring because it reduces cryptic nest defence. Over a century ago, Wallace proposed that sexual dichromatism enhances crypsis of open-nesting females although subsequent studies found that dichromatism per se is not necessarily adaptive. We tested whether reduced female ornamentation in a sexually dichromatic species reduces the risk of clutch depredation and leads to adaptive parental roles in the red-capped plover Charadrius ruficapillus, a species with biparental incubation. Males had significantly brighter and redder head coloration than females. During daytime, when visually foraging predators are active, colour-matched model males incurred a higher risk of clutch depredation than females, whereas at night there was no difference in depredation risk between sexes. In turn, red-capped plovers maintained a strongly diurnal/nocturnal division of parental care during incubation, with males attending the nest largely at night when visual predators were inactive and females incubating during the day. We found support for Wallace's conclusion that reduced female ornamentation provides a selective advantage when reproductive success is threatened by visually foraging predators. We conclude that predators may alter their prey's parental care patterns and therefore may affect parental cooperation during care.

scholarly journals BREEDING SUCCESS OF BUFF-NECKED IBIS (Theristicus caudatus) (PELECANIFORMES: THRESKIORNITHIDAE) IN ARAUCARIA PLATEAU, RIO GRANDE DO SUL, BRAZIL.

2019 ◽  
Vol 16 (31) ◽  
pp. 831-836
Author(s):  
Renata De Boni DAL CORNO ◽  
Gustavo Francisco AVER ◽  
Maria Virginia PETRY
Keyword(s):  
Reproductive Success ◽  
Environmental Changes ◽  
Reproductive Period ◽  
Hatching Rate ◽  
History Of ◽  
Different Populations ◽  
Group B ◽  
Relationship Of ◽  
The Relationship ◽  
Source Of Information

The life history of a species can be considered the main source of information about it, parameters such as incubation period, number of eggs and chicks, may represent the aptitude of individuals in relation to the environment, modified or not. Thus information from the reproductive success of a species allows evaluating the relationship of individuals to environmental changes. This study aimed to assess the reproductive success of three different populations of Buff-necked ibis, Theristicus caudatus, in Araucaria Plateau. The groups were followed in the reproductive season of 2011, three breeding which had environmental characteristics different from each other. We used three methods to determine the reproductive success: apparent success, hatching rate of eggs and protocol of Mayfield. In 600 hours of observation during the reproductive period, approximately 200 hours for each group, there was an average of 1.87 ± 0.74 eggs per nest. The apparent success and the protocol of Mayfield showed proportional differences between the groups. The environment where individuals were nesting in group B can be considered a compromise between the characteristics of other groups, with anthropogenic characteristics that draw predators away from nests and feeding areas, while feeding sites has reduced external influences.

scholarly journals Fertility rebound and economic growth. New evidence for 18 countries over the period 1970–2011

Equilibrium ◽  
2015 ◽  
Vol 10 (1) ◽  
pp. 91 ◽  
Author(s):  
Piotr Dominiak ◽  
Ewa Lechman ◽  
Anna Okonowicz
Keyword(s):  
Economic Growth ◽  
Total Fertility Rate ◽  
Fertility Rate ◽  
Fertility Rates ◽  
Development Indicators ◽  
Fertility Trends ◽  
Long Run ◽  
Time Variations ◽  
New Evidence ◽  
The Relationship

Long-run impact of economic growth on fertility trends is ambiguous and sensitive for in-time variations. Noticeably, over last decades, economic growth has led to significant falls in total fertility rates in many countries. However, recently, in high-income economies a kind of ‘fertility rebound’ emerged (Goldstein, 2009; Luci and Thevenon, 2011; Day, 2012), which supports the hypothesis that reversal trends in total fertility rates are mainly attributed to economic growth. The paper unveils the relationship between total fertility rate changes and economic growth in 18 selected countries with fertility rebound observed, over the period 1970–2011, and detects the GDP-threshold at which the fertility rebound emerged. To report on the relationship we deploy longitudinal data analysis assuming non-linearity between examined variables. The data applied are exclusively derived from World Development Indicators 2013. Our main findings support the hypothesis on U-shaped relationship between the total fertility rate and economic growth in analyzed countries in 1970-2011. Along with the previous, we project the minimum level of GDP per capita (GDP-threshold) when the fertility rebound takes place.

scholarly journals The Cradle of Humankind: Evolutionary Approaches to Technology and Parenting

2019 ◽  
Author(s):  
Geoff Kushnick
Keyword(s):  
Developing Countries ◽  
Evolutionary Theory ◽  
Cross Cultural ◽  
Behavioural Ecology ◽  
Soap Operas ◽  
Fertility Rates ◽  
Dual Inheritance Theory ◽  
Cradle Of Humankind ◽  
The Relationship ◽  
Dual Inheritance

This chapter explores the relevance of evolutionary theory for understanding the relationship between technology and parenting. It does this by elaborating two examples -- one related to childbearing and one to childrearing -- for each of the three major paradigms in the application of evolutionary theory to human behaviour: human behavioural ecology, evolutionary psychology, and dual-inheritance theory. The examples range from a cross-cultural test of the idea that heavier female contribution to subsistence will lead to the development of more elaborate baby-carrying technology, to the demonstrated role tv-broadcasted soap operas have played in lowering fertility rates in some developing countries.

Gender Ideology and Fertility: Evidence for a Curvilinear Hypothesis

2020 ◽  
Author(s):  
Serena Stefani ◽  
Gabriele Prati
Keyword(s):  
Gender Ideology ◽  
Two Dimensions ◽  
Curvilinear Relationship ◽  
World Population ◽  
Fertility Rates ◽  
The World ◽  
And Gender ◽  
Using Data ◽  
National Analysis ◽  
The Relationship

Research on the relationship between fertility and gender ideology revealed inconsistent results. In the present study, we argue that inconsistencies may be due to the fact that such relationship may be nonlinear. We hypothesize a U- shaped relationship between two dimensions of gender ideology (i.e. primacy of breadwinner role and acceptance of male privilege) and fertility rates. We conducted a cross-national analysis of 60 countries using data from the World Values Survey as well as the World Population Prospects 2019. Controlling for gross domestic product, we found support for a U-shaped relationship between gender ideology and fertility. Higher levels of fertility rates were found at lower and especially higher levels of traditional gender ideology, while a medium level of gender ideology was associated with the lowest fertility rate. This curvilinear relationship is in agreement with the phase of the gender revolution in which the country is located. Traditional beliefs are linked to a complementary division of private versus public sphere between sexes, while egalitarian attitudes are associated with a more equitable division. Both conditions strengthen fertility. Instead, as in the transition phase, intermediate levels of gender ideology’s support are associated with an overload and a difficult reconciliation of the roles that women have to embody (i.e. working and nurturing) so reducing fertility. The present study has contributed to the literature by addressing the inconsistencies of prior research by demonstrating that the relationship between gender ideology and fertility rates is curvilinear rather than linear.

scholarly journals Temporal changes in reproductive success and optimal breeding decisions in a long-distance migratory bird

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Cynthia Reséndiz-Infante ◽  
Gilles Gauthier
Keyword(s):  
Reproductive Success ◽  
Clutch Size ◽  
Environmental Changes ◽  
Migratory Bird ◽  
Laying Date ◽  
Negative Consequences ◽  
Breeding Phenology ◽  
Additional Time ◽  
Long Distance ◽  
Seasonal Decline

AbstractMany avian migrants have not adjusted breeding phenology to climate warming resulting in negative consequences for their offspring. We studied seasonal changes in reproductive success of the greater snow goose (Anser caerulescens atlantica), a long-distance migrant. As the climate warms and plant phenology advances, the mismatch between the timing of gosling hatch and peak nutritive quality of plants will increase. We predicted that optimal laying date yielding highest reproductive success occurred earlier over time and that the seasonal decline in reproductive success increased. Over 25 years, reproductive success of early breeders increased by 42%, producing a steeper seasonal decline in reproductive success. The difference between the laying date producing highest reproductive success and the median laying date of the population increased, which suggests an increase in the selection pressure for that trait. Observed clutch size was lower than clutch size yielding the highest reproductive success for most laying dates. However, at the individual level, clutch size could still be optimal if the additional time required to acquire nutrients to lay extra eggs is compensated by a reduction in reproductive success due to a delayed laying date. Nonetheless, breeding phenology may not respond sufficiently to meet future environmental changes induced by warming temperatures.

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