The relationship between parental age and reproductive effort in the California Gull (Larus californicus)

1983 ◽  
Vol 13 (3) ◽  
pp. 161-171 ◽  
Author(s):  
Bruce H. Pugesek
Keyword(s):  
Reproductive Effort ◽  
Parental Age ◽  
The Relationship

The relationship between protein nutrition, reproductive effort and breakdown in immunity toTeladorsagia circumcinctain periparturient ewes

2001 ◽  
Vol 72 (3) ◽  
pp. 595-606 ◽  
Author(s):  
J.G. M. Houdijk ◽  
I. Kyriazakis ◽  
F. Jackson ◽  
R. L. Coop
Keyword(s):  
Host Resistance ◽  
Dry Matter ◽  
Reproductive Effort ◽  
Late Pregnancy ◽  
Gastrointestinal Nematodes ◽  
Dry Matter Intake ◽  
Teladorsagia Circumcincta ◽  
Nutrient Partitioning ◽  
Ad Libitum ◽  
The Relationship

AbstractA nutritional hypothesis for the occurrence of the periparturient relaxation of immunity (PPRI) to gastrointestinal nematodes was tested within the bounds of a nutrient partitioning framework. It was hypothesized that at times of a scarce supply of metabolizable protein (MP), an increase in MP supply or a reduction in MP demand (having singles instead of twins) should lower the extent of PPRI in sheep. Twenty-one single- and 21 twin-bearing and -rearing Finn-Dorset ewes, 2 to 7 years old, and repeatedly infected withTeladorsagia circumcincta, were given one of three pelleted foods (no. = 7). The foods were formulated to supply 0·8 (L), 1·0 (M) and 1·2 (H) times the MP requirements during lactation, and were offeredad libitumfrom d–21to d35(d0 is day of parturition). Faecal egg counts (FEC) were assessed twice weekly as an indicator for host resistance. Dry-matter intake (DMI) during late pregnancy was higher than expected, and MP supply did not limit performance at this stage. In accordance with the hypothesis, there were no indications of a breakdown of immunity toT. circumcinctaduring late pregnancy. DMI during lactation did not differ between the single- and twin-rearing ewes. Calculated milk production was lower for the L than for the M and H ewes, especially for the twin-rearing ewes. A temporarily elevated FEC was observed during the first few days in lactation, which was probably mainly due to changes in faecal output rather than to PPRI. The FEC returned to low, late pregnancy levels at d12and remained low for the single- but not for the twin-rearing ewes (P< 0·001). Overall, the L ewes had higher FEC than the M and H ewes from d19onwards; this effect was more pronounced for the twin- than for the single-rearing ewes. It was postulated that DMI achieved overcame MP scarcity and thus prevented breakdown in immunity in the single-rearing ewes. The data support the view that, at times of MP scarcity, an increase in MP supply and reduction in MP demand can lower the extent of the breakdown in immunity towardsT. circumcincta.

The reproductive effort of Lepeophtheirus pectoralis (Copepoda: Caligidae): insights into the egg production strategy of parasitic copepods

Parasitology ◽  
2015 ◽  
Vol 143 (1) ◽  
pp. 87-96 ◽  
Author(s):  
D. G. FRADE ◽  
M. J. SANTOS ◽  
F. I. CAVALEIRO
Keyword(s):  
Egg Production ◽  
Egg Size ◽  
Reproductive Effort ◽  
Parasitic Copepods ◽  
Egg Number ◽  
Production Strategy ◽  
European Flounder ◽  
Fish Hosts ◽  
First Time ◽  
The Relationship

SUMMARYThe reproductive effort of Lepeophtheirus pectoralis (Müller O. F., 1776), a caligid copepod, which is commonly found infecting the European flounder, Platichthys flesus (Linnaeus, 1758), is studied in detail for the first time. Seasonal variation in body dimensions and reproductive effort are analysed. Data for 120 ovigerous females, 30 from each season of the year, were considered in the analyses. Females were larger and produced a larger number of smaller eggs in winter, than during the summer. The relationship between egg number and egg size is similar to that recorded for other copepods exploiting fish hosts. Much of the recorded variation was also similar to that reported for a copepod parasitic on an invertebrate host, which suggests the possibility of a general trend in copepod reproduction. Overall, our results provide further support for the hypothesis that there is an alternation of summer and winter generations.

Forced Copulation as a Reproductive Strategy of Male Lesser Scaup: a Field Test of Some Predictions

Behaviour ◽  
1985 ◽  
Vol 92 (1-2) ◽  
pp. 146-167 ◽  
Author(s):  
Alan D. Afton
Keyword(s):  
Reproductive Effort ◽  
Strong Support ◽  
Pair Formation ◽  
Exact Nature ◽  
Natural Conditions ◽  
Annual Variations ◽  
Lesser Scaup ◽  
Forced Copulation ◽  
And Performance ◽  
The Relationship

I presented evidence that sperm transfer can occur during forced copulation (FC) under natural conditions, and tested predictions of the fertilization strategy hypothesis, with field data from a marked population of lesser scaup breeding in southwestern Manitoba. As predicted, males directed FC attempts at fertilizable females and seemingly had tactics that increased their effectiveness in inseminating such females. Males selected older females (the more productive) when attempting FCs in 1 year of the study. FC rates were highest in the morning when chances of successful fertilization were probably highest. FC rates were positively correlated with annual variations in female reproductive effort and performance, but the exact nature of the relationship requires further study. Mate-and nonmate-defense by males and other behaviours which probably function as anticuckoldry tactics were observed. Contrary to BARASH'S (1977a) prediction, paired males attempted FCs more frequently than did unpaired males. Although pair formation through mate-switches is probably a more profitable strategy than FC for unpaired males, FC may be an important "last resort" strategy for older, experienced unpaired males late in the season. In general, my results provided strong support for the male fertilization strategy hypothesis.

P.7.e.003 The relationship between parental age and child psychopathology

2009 ◽  
Vol 19 ◽  
pp. S693-S694
Author(s):  
T. Fidan ◽  
I. Esin ◽  
H. Ceyhun ◽  
S. Gürsoy
Keyword(s):  
Child Psychopathology ◽  
Parental Age ◽  
The Relationship

scholarly journals INTRASPECIFIC VARIATION IN THE REPRODUCTIVE EFFORT AMONG THREE POPULATIONS OF AN INTERTIDAL GASTROPOD, Nerita japonica (Dunker)

2012 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Carolus Paruntu
Keyword(s):  
Body Size ◽  
Intraspecific Variation ◽  
Rocky Shore ◽  
Reproductive Effort ◽  
Dry Weight ◽  
Mature Gonad ◽  
Adult Body ◽  
Intertidal Gastropod ◽  
Intertidal Habitats ◽  
The Relationship

The aim of the present research is to figure out the reproductive effort of Nerita japonica occurring in three different intertidal habitats of Amakusa Shimoshima Island, western Kyushu, Japan. Rocky shore population and other two stony shore populations (the upper stony shore and the lower stony shore) were described based on: (a) its mean mature gonad dry weight, (b) reproductive effort, and (c) the relationship between reproductive effort and body size. Data recorded in the period of spawning season. The results revealed that there were mean mature gonad dry weight and reproductive effort variations among three snail populations. Mean mature gonad dry weight and reproductive effort were larger for the Rocky shore population, intermediate for lower stone shore population, and smaller for the upper stone shore population. In one out of three populations, i.e., the upper stone shore population, reproductive effort of mature females increased significantly with an increase in body size. The data showed that reproductive effort is related to adult body size of N. japonica. There was an intraspecific variation in reproductive effort among three populations of N. japonica over even small geographic distances. Keywords: mature body size, mature gonad dry weight, reproductive effort, intraspecific variation, Nerita japonica.  Variasi Indeks Kematangan Gonad Interspesies pada Tiga Populasi Gastropoda Intertidal, Nerita japonica (Dunder)) Penelitian ini bertujuan untuk mendeskripsikan indeks kematangan gonad dari gastropoda intertidal, Nerita japonica yang hidup di tiga habitat yang berbeda di Pulau Shimoshima Amakusa, Kyushu bagian barat, Jepang. Parameter yang diamati pada setiap populasi adalah: (a) nilai rata-rata berat kering gonad matang, (b) indeks kematangan gonad, dan (c) hubungan antara indeks kematangan gonad dan ukuran tubuh. Data dicatat pada periode musim pemijahan. Ketiga populasi memperlihatkan nilai rata-rata berat kering gonad yang matang dan indeks kematangan gonad yang berbeda. Populasi pantai berbatu memiliki nilai rata-rata berat kering matang gonad dan indeks kematangan gonad yang paling besar, diikuti oleh nilai dari populasi pantai berbatu bagian bawah dan populasi pantai berbatu bagian atas memiliki nilai yang paling kecil. Selanjutnya, satu dari tiga populasi, yaitu populasi pantai berbatu bagian atas memperlihatkan indeks kematangan gonad dari individu-individu betina N. japonica berhubungan dengan ukuran tubuhnya. Sekalipun indeks kematangan gonad dari individu-individu N. japonica meningkat secara signifikan dengan bertambahnya ukuran tubuh, namun terdapat variasi intraspesifik pada N. japonica dalam hal indeks kematangan gonad menurut habitat walaupun secara geografis berdekatan.Kata kunci: ukuran tubuh matang kelamin, berat kering gonad matang, indeks kematangan gonad, variasi intraspesifik, Nerita japonica.

The Effects of Parental Age and Sibling Configurations on Family Environment and Academic Achievement of Children

2008 ◽  
Vol 2 (1) ◽  
pp. 13-35 ◽  
Author(s):  
Nancy Shields ◽  
Christine Hanneke
Keyword(s):  
Academic Achievement ◽  
Family Environment ◽  
Ordinal Position ◽  
Gender Composition ◽  
Parental Age ◽  
Sibship Size ◽  
Quality Of Relationships ◽  
And Gender ◽  
The Relationship

In this study, we draw from the literature on sibling configurations and parental age to investigate the effects of these factors on the academic achievement of children. The study investigates the effects of maternal age at first birth, maternal age when the respondent was born, and father's age when the respondent was born on ACT scores, grade point averages over three years, and whether or not the parents are providing financial aid to their students. We examine the effects of sibship size, ordinal position, and gender composition of the sibship on these same variables. The study also investigates the extent to which the relationship between parental age and academic outcomes is linear. The relationship of sibship size, ordinal position, and gender composition on the quality of relationships with parents is investigated. Using a sample of freshmen at a mid-western university, we find consistent positive effects of parental age on high school and early college achievement, as well as consistent negative birth order effects on achievement at the high school level. Students with older parents and fewer older siblings consistently performed better. Sibship size and the proportion of females in the sibship had no effect on academic outcomes. Using self-reported data from children on a childhood measure of parental support and interaction and quality of relationships with parents during late adolescence, we also investigate the impact of parental age at birth, and sibling characteristics on childhood and adolescent family environment. Ordinal position had a significant positive effect on the quality of relationships with parents during adolescence, and sibship size had a significant negative effect. We find a curvilinear effect for paternal age on childhood support and parental involvement, but not for academic achievement or quality of relationships with parents in late adolescence. Parental education had a positive significant impact on childhood support and involvement. Children from larger sibships and who were later born children were less likely to receive financial aid from their parents. The results are discussed as they relate to the literature on parental age and sibling configurations, and in terms of their implications for student retention and success.

The Relationship Between Food Supply, Reproductive Effort and Breeding Success in Arctic Terns Sterna paradisaea

10.2307/4999 ◽  
1989 ◽  
Vol 58 (1) ◽  
pp. 261 ◽  
Author(s):  
P. Monaghan ◽  
J. D. Uttley ◽  
M. D. Burns ◽  
C. Thaine ◽  
J. Blackwood
Keyword(s):  
Breeding Success ◽  
Food Supply ◽  
Reproductive Effort ◽  
Sterna Paradisaea ◽  
The Relationship
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