The allocation between egg size and clutch size depends on local nest survival rate in a mean of bet-hedging in a shorebird

Abstract Background The allocation of resources between offspring size and number is a central question of life-history theory. Although several studies have tested the existence of this trade-off, few studies have investigated how environmental variation influences the allocation of resources to offspring size and offspring number. Additionally, the relationship between population dynamics and the offspring size and number allocation is far less understood. Methods We investigate whether resource allocation between egg size and clutch size is influenced by the ambient temperature and whether it may be related to apparent nest survival rate. We measured 1548 eggs from 541 nests of two closely related shorebird species, the Kentish Plover (Charadrius alexandrinus) and the White-faced Plover (C. dealbatus) in China, in four populations that exhibit contrasting ambient environments. We weighed females, monitored nest survival, and calculated the variance of ambient temperature. Results Although we found that egg size and clutch size were all different between the four breeding populations, the reproductive investment (i.e. total clutch volume) was similar between populations. We also found that populations with a high survival rate had relatively larger eggs and a smaller clutch than populations with a low nest survival rate. The latter result is in line with a conservative/diversified bet-hedging strategy. Conclusions Our findings suggest that plovers may increasing fitness by investing fewer, larger or many, small according local nest survival rate to make a similar investment in reproduction, and thereby may have an impact on population demography.

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Within-clutch egg-size variation in a subsocial bug: the positional effect hypothesis

Canadian Journal of Zoology ◽

10.1139/z06-163 ◽

2006 ◽

Vol 84 (11) ◽

pp. 1540-1544 ◽

Cited By ~ 11

Author(s):

Shin-ichi Kudo

Keyword(s):

Predation Risk ◽

Clutch Size ◽

Egg Size ◽

Size Variation ◽

Instar Nymph ◽

Offspring Size ◽

Egg Mass ◽

Female Body Size ◽

Positional Effect ◽

Effect Hypothesis

If there are differences in predation risk among the offspring within a clutch, parents should allocate less resources to the offspring facing higher risk. Predation risk, and thus offspring size, may depend on the spatial position of individual offspring within a clutch. To test this positional effect hypothesis, I examined egg-size (egg-mass) variation in the subsocial bug Elasmucha signoreti Scott, 1874 (Hemiptera: Acanthosomatidae). In subsocial insects, including Elasmucha , in which females guard their clutches against predators by covering the clutch with their bodies, there are large differences in survival between offspring at the centre and at the periphery of the clutch. There was considerable variation in reproductive output among females; female body size was positively correlated with egg mass but not with clutch size. Females laid significantly lighter eggs in the peripheral, and thus more vulnerable, part of the clutch. No phenotypic trade-off between egg mass and clutch size was detected. Egg mass was positively correlated with hatched first-instar nymph mass. Thus, E. signoreti females seem to allocate their resources according to the different predation risks faced by the offspring within a clutch. I suggest that the positional effect hypothesis can generally be applicable to species whose females lay eggs in clutches and that the eggs suffer different mortality rates which depend on their spatial positions within the clutch.

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

Amphibia-Reptilia ◽

10.1163/156853806778877167 ◽

2006 ◽

Vol 27 (4) ◽

pp. 505-511 ◽

Cited By ~ 2

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.

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Contrasting reproductive strategies in a narrow latitude range: the case of D’Orbigny’s slider

Amphibia-Reptilia ◽

10.1163/15685381-00003122 ◽

2017 ◽

Vol 38 (4) ◽

pp. 425-434

Author(s):

Priscila Silva Lucas ◽

Alex Bager

Keyword(s):

Body Size ◽

Clutch Size ◽

Evolutionary Biology ◽

Egg Size ◽

Life History Theory ◽

Geographical Area ◽

Size Variation ◽

Reproductive Traits ◽

Maternal Body ◽

Trade Offs

Reproductive traits and the level of parental investment in offspring varies between individuals and species. These are central issues in life history theory and evolutionary biology. Maternal body size plays an important role in reproduction, and we usually observe variable investment in offspring by females. Thus, optimal egg size may not be reached in some populations or species. In this study, we tested if reproductive traits differed between populations of D’Orbigny’s slider in a specific geographical area in Brazil. We evaluated the relationship between reproductive traits to maternal body size and clutch size to egg size to determine possible trade-offs across populations. At the population level, maternal body size and reproductive traits of D’Orbigny’s slider were different even in geographically nearby areas. Maternal body size had a positive effect on clutch size, but not on egg size, except in the Arroio Grande population. Nevertheless, we did not observe a negative correlation between clutch and egg size in any population. Although maternal body size had effects in the different populations explaining most of the variation of clutch size, variation in egg size may be the result of decreased survival chances in unpredictable environments and possibly morphological constraints. The trade-off between egg size and number was not observed and this could be expected if resource availability and reproductive allocation by females vary greatly among individuals.

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Terrestrial reproduction and parental care drive rapid evolution in the trade-off between offspring size and number across amphibians

PLoS Biology ◽

10.1371/journal.pbio.3001495 ◽

2022 ◽

Vol 20 (1) ◽

pp. e3001495

Author(s):

Andrew I. Furness ◽

Chris Venditti ◽

Isabella Capellini

Keyword(s):

Parental Care ◽

Clutch Size ◽

Egg Size ◽

Direct Development ◽

Life History Strategies ◽

Offspring Size ◽

Trade Off ◽

Offspring Development ◽

Egg Brooding ◽

Tadpole Transport

The trade-off between offspring size and number is central to life history strategies. Both the evolutionary gain of parental care or more favorable habitats for offspring development are predicted to result in fewer, larger offspring. However, despite much research, it remains unclear whether and how different forms of care and habitats drive the evolution of the trade-off. Using data for over 800 amphibian species, we demonstrate that, after controlling for allometry, amphibians with direct development and those that lay eggs in terrestrial environments have larger eggs and smaller clutches, while different care behaviors and adaptations vary in their effects on the trade-off. Specifically, among the 11 care forms we considered at the egg, tadpole and juvenile stage, egg brooding, male egg attendance, and female egg attendance increase egg size; female tadpole attendance and tadpole feeding decrease egg size, while egg brooding, tadpole feeding, male tadpole attendance, and male tadpole transport decrease clutch size. Unlike egg size that shows exceptionally high rates of phenotypic change in just 19 branches of the amphibian phylogeny, clutch size has evolved at exceptionally high rates in 135 branches, indicating episodes of strong selection; egg and tadpole environment, direct development, egg brooding, tadpole feeding, male tadpole attendance, and tadpole transport explain 80% of these events. By explicitly considering diversity in parental care and offspring habitat by stage of offspring development, this study demonstrates that more favorable conditions for offspring development promote the evolution of larger offspring in smaller broods and reveals that the diversity of parental care forms influences the trade-off in more nuanced ways than previously appreciated.

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Follicle ablation increases offspring size in a lizard with a low clutch frequency

Amphibia-Reptilia ◽

10.1163/156853809788795119 ◽

2009 ◽

Vol 30 (3) ◽

pp. 361-366 ◽

Cited By ~ 2

Author(s):

Xiang Ji ◽

Yuan Xia ◽

Zheng Wang

Keyword(s):

Reproductive Success ◽

Clutch Size ◽

Breeding Season ◽

Egg Size ◽

Offspring Size ◽

Offspring Number ◽

Available Energy ◽

Lacertid Lizard ◽

Individual Offspring ◽

High Fraction

AbstractStudies of lizards and snakes have shown that an experimental reduction of offspring number sometimes, but not always, results in an increase in offspring size. We applied the “follicle ablation” technique to an oviparous lacertid lizard (Eremias argus) to test the hypothesis that offspring size can be easily altered by manipulating clutch size in species with a low clutch frequency. Our manipulation of clutch size had the effect of inducing variation in egg size in the first post-surgical clutch, with follicle-ablated females producing fewer larger eggs than did controls. Follicle-ablated females produced a second post-surgical clutch as normally as did controls. The proportional amount of resources allocated to reproduction did not shift seasonally in E. argus, but females normally switched from producing a larger number of smaller eggs early in the breeding season to a smaller number of larger eggs later in the season. Females used in this study never produce more than two clutches per breeding season. Therefore, our data validate the hypothesis tested. Our data also provide an inference that maximization of reproductive success could be achieved in females of E. argus by diverting a larger enough, rather than an extraordinarily high, fraction of the available energy to individual offspring in single reproductive episodes.

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Impacts of ambient temperature and clutch size on incubation behaviour onset in a female‐only incubator songbird

Ibis ◽

10.1111/ibi.12937 ◽

2021 ◽

Author(s):

David Diez‐Méndez ◽

Juan José Sanz ◽

Emilio Barba

Keyword(s):

Ambient Temperature ◽

Clutch Size ◽

Incubation Behaviour

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High survival rate in advanced-stage B-cell lymphomas and leukemias without CNS involvement with a short intensive polychemotherapy: results from the French Pediatric Oncology Society of a randomized trial of 216 children.

Journal of Clinical Oncology ◽

10.1200/jco.1991.9.1.123 ◽

1991 ◽

Vol 9 (1) ◽

pp. 123-132 ◽

Cited By ~ 203

Author(s):

C Patte ◽

T Philip ◽

C Rodary ◽

J M Zucker ◽

H Behrendt ◽

...

Keyword(s):

Survival Rate ◽

B Cell ◽

Pediatric Oncology ◽

Stage Iv ◽

High Dose ◽

High Survival ◽

Advanced Stage ◽

High Survival Rate ◽

Cns Involvement

From April 1984 to December 1987, the French Pediatric Oncology Society (SFOP) organized a randomized trial for advanced-stage B-cell lymphoma without CNS involvement to study the possibility of reducing the length of treatment to 4 months. After receiving the same three intensive six-drug induction courses based on high-dose fractionated cyclophosphamide, high-dose methotrexate (HD MTX), and cytarabine in continuous infusion, patients were evaluated for remission. Those who achieved complete remission (CR) were randomized between a long arm (five additional courses with two additional drugs; 16 weeks of treatment) and a short arm (two additional courses; 5 weeks). For patients in partial remission (PR), intensification of treatment was indicated. Two hundred sixteen patients were registered: 15 stage II nasopharyngeal and extensive facial tumors, 167 stage III, and 34 stage IV, 20 of the latter having more than 25% blast cells in bone marrow. The primary sites of involvement were abdomen in 172, head and neck in 30, thorax in two, and other sites in 12. One hundred sixty-seven patients are alive in first CR with a minimum follow-up of 18 months; four are lost to follow-up. Eight patients died from initial treatment failure, 14 died from toxicity or deaths unrelated to tumor or treatment, and 27 relapsed. The event-free survival (EFS), with a median follow-up of 38 months, is 78% (SE 3) for all the patients, 73% (SE 11) for the stage II patients, 80% (SE 3) for the stage III patients, and 68% (SE 8) for the stage IV and acute lymphoblastic leukemia (ALL) patients. One hundred sixty-six patients were randomized: 82 in the short arm and 84 in the long arm. EFS is, respectively, 89% and 87%. Statistical analysis confirms equivalence of both treatment arms with regard to EFS. Moreover, morbidity was lower in the short arm. This study confirms the high survival rate obtained in the previous LMB 0281 study without radiotherapy or debulking surgery and demonstrates the effectiveness of short treatment.

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Survival Rate of 1008 Short Dental Implants with 21 Months of Average Follow-Up: A Retrospective Study

Journal of Clinical Medicine ◽

10.3390/jcm9123943 ◽

2020 ◽

Vol 9 (12) ◽

pp. 3943

Author(s):

João Caramês ◽

Ana Catarina Pinto ◽

Gonçalo Caramês ◽

Helena Francisco ◽

Joana Fialho ◽

...

Keyword(s):

Retrospective Study ◽

Survival Rate ◽

Dental Implants ◽

Cox Regression ◽

Survival Rates ◽

High Survival ◽

Implant Survival ◽

Posterior Maxilla ◽

Clinical Records

This retrospective study evaluated the survival rate of short, sandblasted acid-etched surfaced implants with 6 and 8 mm lengths with at least 120 days of follow-up. Data concerning patient, implant and surgery characteristics were retrieved from clinical records. Sandblasted and acid-etched (SLA)-surfaced tissue-level 6 mm (TL6) or 8 mm (TL8) implants or bone-level tapered 8 mm (BLT8) implants were used. Absolute and relative frequency distributions were calculated for qualitative variables and mean values and standard deviations for quantitative variables. A Cox regression model was performed to verify whether type, length and/or width influence the implant survival. The cumulative implant survival rate was assessed by time-to-event analyses (Kaplan–Meier estimator). In all, 513 patients with a mean age of 58.00 ± 12.44 years received 1008 dental implants with a mean follow-up of 21.57 ± 10.77 months. Most implants (78.17%) presented a 4.1 mm diameter, and the most frequent indication was a partially edentulous arch (44.15%). The most frequent locations were the posterior mandible (53.97%) and the posterior maxilla (31.55%). No significant differences were found in survival rates between groups of type, length and width of implant with the cumulative rate being 97.7% ± 0.5%. Within the limitations of this study, the evaluated short implants are a predictable option with high survival rates during the follow-up without statistical differences between the appraised types, lengths and widths.

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