scholarly journals Egg-size and -number variations related to maternal size and age, and the relationship between egg size and larval characteristics in an annual marine gastropod, Haloa japonica (Opisthobranchia; Cephalaspidea)

1997 ◽  
Vol 152 ◽  
pp. 187-195 ◽  
Author(s):  
K Ito
Keyword(s):  
Egg Size ◽  
Marine Gastropod ◽  
Maternal Size ◽  
The Relationship

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.

scholarly journals Mother-Offspring Relations: Prey Quality and Maternal Size Affect Egg Size of an Acariphagous Lady Beetle in Culture

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Eric W. Riddick ◽  
Zhixin Wu
Keyword(s):  
Body Size ◽  
Egg Size ◽  
Lima Bean ◽  
Hind Femur ◽  
Spider Mites ◽  
Lady Beetle ◽  
High Rate ◽  
Phaseolus Lunatus ◽  
Maternal Size ◽  
Prey Quality

We investigated mother-offspring relations in a lady beetleStethorus punctillumWeise that utilizes spider mites as prey. Our objectives were to determine if (1) prey quality affects egg size, (2) maternal size correlates with egg size, and (3) egg size affects hatching success. We fed predators spider mitesTetranychus urticaeKoch from lima beanPhaseolus lunatusL. foliage in the laboratory. Mothers of unknown body size offered high rather than low quality spider mites since birth produced larger eggs. Mothers of known body size offered only high quality spider mites, produced eggs of variable size, but mean egg size correlated positively with hind femur length. Mothers laid their eggs singly, rather than in batches, and eggs were large relative to femur size. Egg size did not affect hatch success; mean hatch rate exceeded 95% regardless of egg size. In conclusion, the quality of prey consumed byS. punctillummothers while in the larval stage can affect their size as adults and, consequently, the size of their eggs. The behavior of laying eggs singly, the positive relationship between maternal size and mean egg size, and the high rate of egg hatch suggest thatS. punctillummothers invest heavily in offspring.

Egg size, contents, and quality: maternal-age and -size effects on house fly eggs

2000 ◽  
Vol 78 (9) ◽  
pp. 1544-1551 ◽  
Author(s):  
G S McIntyre ◽  
R H Gooding
Keyword(s):  
Clutch Size ◽  
Size Effects ◽  
Maternal Age ◽  
Egg Size ◽  
Egg Quality ◽  
Size Variation ◽  
House Fly ◽  
Egg Volume ◽  
Hatch Rate ◽  
Maternal Size

Egg size is generally regarded as a good predictor of egg quality. However, in phenotypic studies it is difficult to separate the effects of egg-size variation from the effects of the underlying cause of the differences in egg size. We examined the relationships between the size, shape, hatch rate, and biochemical and energy contents of house fly (Musca domestica L.) eggs using two distinct sources of egg-size variation: maternal age and maternal size. By comparing relationships among egg parameters between manipulations we were able to distinguish some maternal effects from pure egg-size effects. Maternal age was negatively correlated with clutch size, egg volume, hatch rate, and lipid content, but was not correlated with protein, carbohydrate, or energy content. Female size did not affect hatch rate or biochemical and energy contents, but was positively correlated with clutch size and egg volume. Partial correlation analyses revealed that egg-size variation due to maternal-age effects was unrelated to hatch rate, but that egg-size variation due to maternal-size effects was weakly negatively correlated with hatch rate. The results suggest that large and small house fly eggs differ primarily in size and that within size classes there is significant variation in other egg parameters. Size is not a useful predictor of egg quality in this system.

scholarly journals ISOMETRY OF EGG SIZE IN A TEXAS POPULATION OF THE TURTLE STERNOTHERUS ODORATUS THAT EXHIBITS A NEARLY FIXED CLUTCH SIZE

2020 ◽  
pp. 13-17
Author(s):  
Peter V. Lindeman
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Egg Size ◽  
Female Body Size ◽  
Competing Demands ◽  
Sternotherus Odoratus ◽  
Central Texas ◽  
Relationship Of ◽  
The Relationship ◽  
Anatomical Constraints

In evaluating optimal egg-size theory and the effects of anatomical constraints on egg size in turtles, pivotal questions concern the significance of the relationship of egg size to female body size and whether the relationship is isometric or hypoallometric. In a central Texas population of the kinosternid turtle Sternotherus odoratus in which clutch size of a sample of turtles was nearly fixed (seven of eight females had two eggs while the largest female had three eggs), there was an isometric increase in egg width with body size among the females with two-egg clutches and significantly reduced egg width in the largest female’s three-egg clutch. Allometric analyses of populations that exhibit little variation in clutch size, as well as analysis of modal clutch sizes in populations with more variable clutch sizes, both have the potential to further illuminate the competing demands of increasing egg size vs. increasing clutch size as females grow larger, enabling them to optimize their reproductive output as it increases with body size.

scholarly journals The relationship between egg size and helper number in cooperative breeders: a meta-analysis across species

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4028 ◽  
Author(s):  
Tanmay Dixit ◽  
Sinead English ◽  
Dieter Lukas
Keyword(s):  
Life History ◽  
Social Environment ◽  
Group Size ◽  
Egg Size ◽  
Reproductive Investment ◽  
Maternal Investment ◽  
Differential Allocation ◽  
The Social ◽  
Cooperatively Breeding ◽  
The Relationship

BackgroundLife history theory predicts that mothers should adjust reproductive investment depending on benefits of current reproduction and costs of reduced future reproductive success. These costs and benefits may in turn depend on the breeding female’s social environment. Cooperative breeders provide an ideal system to test whether changes in maternal investment are associated with the social conditions mothers experience. As alloparental helpers assist in offspring care, larger groups might reduce reproductive costs for mothers or alternatively indicate attractive conditions for reproduction. Thus, mothers may show reduced (load-lightening) or increased (differential allocation) reproductive investment in relation to group size. A growing number of studies have investigated how cooperatively breeding mothers adjust pre-natal investment depending on group size. Our aim was to survey these studies to assess, first, whether mothers consistently reduce or increase pre-natal investment when in larger groups and, second, whether these changes relate to variation in post-natal investment.MethodsWe extracted data on the relationship between helper number and maternal pre-natal investment (egg size) from 12 studies on 10 species of cooperatively breeding vertebrates. We performed meta-analyses to calculate the overall estimated relationship between egg size and helper number, and to quantify variation among species. We also tested whether these relationships are stronger in species in which the addition of helpers is associated with significant changes in maternal and helper post-natal investment.ResultsAcross studies, there is a significant negative relationship between helper number and egg size, suggesting that in most instances mothers show reduced reproductive investment in larger groups, in particular in species in which mothers also show a significant reduction in post-natal investment. However, even in this limited sample, substantial variation exists in the relationship between helper number and egg size, and the overall effect appears to be driven by a few well-studied species.DiscussionOur results, albeit based on a small sample of studies and species, indicate that cooperatively breeding females tend to produce smaller eggs in larger groups. These findings on prenatal investment accord with previous studies showing similar load-lightening reductions in postnatal parental effort (leading to concealed helper effects), but do not provide empirical support for differential allocation. However, the considerable variation in effect size across studies suggests that maternal investment is mitigated by additional factors. Our findings indicate that variation in the social environment may influence life-history strategies and suggest that future studies investigating within-individual changes in maternal investment in cooperative breeders offer a fruitful avenue to study the role of adaptive plasticity.

The effects of maternal size on clutch traits in a tropical invariant-clutch lizard, Carlia rubrigularis (Scincidae)

2006 ◽  
Vol 27 (4) ◽  
pp. 505-511 ◽  
Author(s):  
Brett Alexander Goodman
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Reproductive Output ◽  
Reproductive Traits ◽  
Theoretical Models ◽  
Offspring Size ◽  
Egg Mass ◽  
Egg Volume ◽  
Maternal Size ◽  
Tropical Australia

AbstractSpecies with an invariant or "fixed" clutch offer a unique opportunity to examine how variation in maternal size relates to key reproductive traits, such as egg size. Theoretical models of offspring size suggest selection should operate to optimize egg size and reproductive output. However, because invariant-clutch species are unable to allocate surplus resources to additional eggs (or offspring) they may exhibit different relationships than those anticipated under theoretical expectations. To test this, I examined relationships between maternal size-egg size in Carlia rubrigularis, an invariant-clutch producing scincid lizard from tropical Australia. C. rubrigularis exhibited relative clutch masses that were lower than variant clutch size species, but which were similar to other invariant clutch size species. However, maternal size (snout-vent length and post-oviposition mass) was correlated with several clutch traits (egg mass, egg width and egg volume), but females in better condition did not produce relatively heavier eggs. These results suggest mechanistic hypotheses may best explain the observed maternal size-egg size relationships in C. rubrigularis.

The role of calcium in constraining egg synthesis in the Audouin’s Gull (Ichthyaetus audouinii)

2013 ◽  
Vol 91 (9) ◽  
pp. 640-645 ◽  
Author(s):  
F. Ramirez ◽  
M. Garcia-Tarrasón ◽  
L. Rami ◽  
M. Genovart ◽  
L. Jover ◽  
...  
Keyword(s):  
Physiological Response ◽  
Reproductive Strategies ◽  
Egg Size ◽  
Potential Role ◽  
Size Variation ◽  
Eggshell Thickness ◽  
Egg Volume ◽  
Causal Inferences ◽  
The Relationship

Understanding how resources are allocated to form eggs is crucial to our better understanding of avian reproductive strategies. However, little is currently known about how egg synthesis in wild birds might be constrained by the availability of specific micronutrients. Here, we investigated the potential role of calcium (Ca) in constraining egg synthesis in the Audouin’s Gull (Ichthyaetus audouinii (Payraudeau, 1826)). In particular, we evaluated the relationship between plasma Ca levels (mg/dL) in incubating females (as an indicator of the physiological response of females to increased Ca demand associated with clutch production) and several fitness-related egg traits such as egg size (i.e., egg volume), egg shape, and eggshell thickness from three-egg clutches. Egg size was positively related with incubating female plasma Ca levels, with the slope of this relationship being significantly higher for later-laid eggs. The observational nature of this study and reversed timing precludes causal inferences, but observed relationships supported the constraining role of Ca in egg synthesis and suggested that Ca may also have a role in modulating the intraclutch pattern of egg-size variation typical of this gull species.

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