Egg size and reproductive strategies of western palearctic birds

1998 ◽  
Vol 65 (2) ◽  
pp. 177-181 ◽  
Author(s):  
Massimo Favaron ◽  
Renato Massa ◽  
Aldo Zullini
Keyword(s):  
Reproductive Strategies ◽  
Egg Size ◽  
Western Palearctic

The reproductive biology of Plutonaster Bifrons, Dytaster Insigns and Psilaster Andromeda (Asteroidea: Astropectinidae) from the Rockall Trough

1982 ◽  
Vol 62 (4) ◽  
pp. 869-887
Author(s):  
P. A. Tyler ◽  
S. L. Pain
Keyword(s):  
Reproductive Biology ◽  
Reproductive Strategies ◽  
Egg Size ◽  
Food Source ◽  
Maximum Size ◽  
Reproductive Synchrony ◽  
Sea Bed ◽  
Rockall Trough ◽  
Sperm Development ◽  
Surface Production

Examination of the reproductive biology of three closely related sympatric astropectinid asteroidshas revealed two distinct reproductive strategies. In Plutonaster bifrons and Dytaster insignis the gonads are serially arranged and open at gonopores located at the tip of genital papillae found on the dorsal arm surface between the bases of the paxillae. The ovaries of these species produce numerous small (ca. 120/«n diameter) eggs which in Plutonaster bifrons appear to show a distinct synchrony of production. Initiation of gametogenesis occurs in June to August of each year with oocyte growthcontinuing until March with a spawn-out in the period March to early June. In specimens where spawningdoesnot occur, there would appear to be internal oocyte degeneration, or after spawning relict oocytesundergo phagocytosis. In males initiation of spermatogenesis may occur in August/September of eachyear but after this synchrony of sperm development is not evident. In Psilaster andromeda gonads are located at the base of the arms and each gonad opens at a single gonopore. A number of small (<300 /«n) oocytes are produced by each gonad. Some of these are phagocytosed and some undergo vitellogenesis and grow to a maximum size of 950 fim before being spawned. Unspent oocytes undergo internal degeneration. In neither females nor males is there any evidence of reproductive synchrony. From these egg sizes, fecundities and gametogenic strategies, we infer indirect planktotrophic development for Plutonaster bifrons, the transfer of a seasonal surface production to deep water providing a food source for developing larvae. The egg size and or close to the sea-bed, as there is no evidence of brooding in this species.

scholarly journals Variations in the reproductive strategies of three populations of Phrynocephalus helioscopus in China

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5705
Author(s):  
Tao Liang ◽  
Lu Zhou ◽  
Wenfeng He ◽  
Lirong Xiao ◽  
Lei Shi
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Reproductive Strategies ◽  
Female Body ◽  
Egg Size ◽  
Reproductive Traits ◽  
Breeding Period ◽  
Female Body Size ◽  
Trade Offs ◽  
Morphological Constraint

Background Egg size and clutch size are key life history traits. During the breeding period, it is possible for females to increase their reproductive output either by increasing the number of eggs if the optimal egg size (OES) is maintained, or by increasing the allocation of energy to each egg. However, the strategies adopted are often influenced by animals’ morphology and environment. Methods Here, we examined variation in female morphological and reproductive traits, tested for trade-offs between egg size and clutch size, and evaluated the relationship between egg size and female morphology in three populations of Phrynocephalus helioscopus. Results Female body size, egg size, and clutch size were larger in the Yi Ning (YN) and Fu Yun (FY) populations than in the Bei Tun (BT) population (the FY and YN populations laid more, and rounder eggs). Egg size was independent of female body size in two populations (BT and FY), even though both populations had an egg-size/clutch size trade-off. In the YN population, egg size and clutch size were independent, but egg size was correlated with female body size, consistent with the hypothesis of morphological constraint. Conclusions Our study found geographical variation in body size and reproductive strategies of P. helioscopus. Egg size was correlated with morphology in the larger-bodied females of the YN population, but not in the smaller-bodied females of the BT population, illustrating that constraints on female body size and egg size are not consistent between populations.

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.

scholarly journals GEOGRAPHIC VARIATION IN CLUTCH SIZE AMONG Lophura AND Syrmaticus PHEASANTS ON TAIWAN AND MAINLAND OF CHINA

2006 ◽  
Vol 28 (63) ◽  
Author(s):  
Zuhao Huang ◽  
Naifa Liu
Keyword(s):  
Life History ◽  
Environmental Factors ◽  
Clutch Size ◽  
Reproductive Strategies ◽  
Egg Size ◽  
Significant Positive Correlation ◽  
Weather Condition ◽  
Life History Evolution ◽  
Breeding Strategy ◽  
The Difference

Clutch size, the important parameters of bird reproduction, directly influences bird reproductive result. The difference of interspecific or/and intraspecific clutch size has been widely applied to explain life history evolution. In order to know the factors limiting clutch size of pheasants on island and examine Ashmole’s hypothesis and Cody’s hypothesis,clutch size and egg size of Lophura swinhoii and Syrmaticus mikado on Taiwan were compared with those of relative species on mainland of China. The average clutch size of L.swinhoii and S.mikado on Taiwan were significantly less than those of relative species on mainland. But the egg size of the two pheasants on Taiwan was notably bigger than those of relative species on mainland. They reduced clutch size and increased egg sizes, their reproductive strategies tended to k-selection. While the relative species on mainland laid more and smaller eggs, their reproductive strategies tended to rselection. The analysis on environmental factors showed the pheasants on Taiwan didn’t support Ashmole’s and Cody’s hypotheses. Unexpected weather condition on island might lead to the breeding strategy on island tend to k-selection. Among Gallinaceous birds, there was a highly significant positive correlation between clutch size and their distributed area, and the number of subspecies. The breeding strategy of pheasants on island was determined by the effects of area and heredity.

The reproductive biology of Plutonaster Bifrons, Dytaster Insigns and Psilaster Andromeda (Asteroidea: Astropectinidae) from the Rockall Trough

1982 ◽  
Vol 62 (4) ◽  
pp. 869-887 ◽  
Author(s):  
P. A. Tyler ◽  
S. L. Pain
Keyword(s):  
Reproductive Biology ◽  
Reproductive Strategies ◽  
Egg Size ◽  
Food Source ◽  
Maximum Size ◽  
Reproductive Synchrony ◽  
Sea Bed ◽  
Rockall Trough ◽  
Sperm Development ◽  
Surface Production

Examination of the reproductive biology of three closely related sympatric astropectinid asteroidshas revealed two distinct reproductive strategies. In Plutonaster bifrons and Dytaster insignis the gonads are serially arranged and open at gonopores located at the tip of genital papillae found on the dorsal arm surface between the bases of the paxillae. The ovaries of these species produce numerous small (ca. 120/«n diameter) eggs which in Plutonaster bifrons appear to show a distinct synchrony of production. Initiation of gametogenesis occurs in June to August of each year with oocyte growthcontinuing until March with a spawn-out in the period March to early June. In specimens where spawningdoesnot occur, there would appear to be internal oocyte degeneration, or after spawning relict oocytesundergo phagocytosis. In males initiation of spermatogenesis may occur in August/September of eachyear but after this synchrony of sperm development is not evident. In Psilaster andromeda gonads are located at the base of the arms and each gonad opens at a single gonopore. A number of small (<300 /«n) oocytes are produced by each gonad. Some of these are phagocytosed and some undergo vitellogenesis and grow to a maximum size of 950 fim before being spawned. Unspent oocytes undergo internal degeneration. In neither females nor males is there any evidence of reproductive synchrony. From these egg sizes, fecundities and gametogenic strategies, we infer indirect planktotrophic development for Plutonaster bifrons, the transfer of a seasonal surface production to deep water providing a food source for developing larvae. The egg size and or close to the sea-bed, as there is no evidence of brooding in this species.

Oviparous reproduction of Vestia ranojevici moravica confirms taxonomic value of life history characters in carpathian clausiliids (Gastropoda: Pulmonata)

Biologia ◽  
2013 ◽  
Vol 68 (4) ◽  
Author(s):  
Anna Sulikowska-Drozd ◽  
Tomasz Maltz
Keyword(s):  
Reproductive Strategies ◽  
Egg Size ◽  
Room Temperature ◽  
Reproductive Tract ◽  
Shell Growth ◽  
Egg Laying ◽  
Anatomical Studies ◽  
One Year ◽  
Previous Assumption ◽  
Actual Size

AbstractBased on five-year observation of 36 snails collected in the Čeladná valley (Moravia, Czech Republic) and their progeny reared in laboratory, it was found that Vestia ranojevici moravica (Brabenec, 1952) is oviparous. The oviparity in V. ranojevici is in line with the previous assumption of its reproductive strategy based on anatomical studies alone. It supports the separate position of the species in the genus Vestiaa (subgenus Brabenecia). V. ranojevici was kept at room temperature (18–25°C) between March and October; in winter snails were stored at 3°C. The egg-laying period started in late March, ca. 1 month after raising the temperature, and lasted till September, with one maximum in spring. In the laboratory the snails laid eggs in batches (usually 4–6 eggs, max 11) or singly. The number of batches per pair per season was 1–8; the corresponding number of eggs — 3–40. The eggs were gelatinous, with separate calcium carbonate crystals in the external envelope. The average egg size was 1.80 × 1.51 mm, but actual size and shape were highly variable: larger and more elongated eggs were produced mainly by laboratory reared animals. Freshly deposited eggs did not contain shelled embryos nor the reproductive tract of dissected individuals contained eggs. At room temperature the eggs hatched after ca. 14–16 days, then the shell growth lasted 20–29 weeks; the snails laid eggs 30 weeks after completion of shell growth indicating one-year life cycle under laboratory conditions. Adult individuals collected in the field reproduced during 4–5 consecutive years. Comparison of V. ranojevici reproduction to the results of breeding of other Carpathian clausiliids in the same laboratory shows that similar reproductive strategies may have evolved independently in different lineages of the group: both the oviparous and egg retaining species belong to the genera Vestia and Balea.

Egg Size and Reproductive Strategies in Insects Infesting Stored-Products

1987 ◽  
Vol 1 (3) ◽  
pp. 229 ◽  
Author(s):  
G. J. Holloway ◽  
R. H. Smith ◽  
A. E. Wrelton ◽  
P. E. King ◽  
Li Li Li ◽  
...  
Keyword(s):  
Reproductive Strategies ◽  
Egg Size ◽  
Stored Products

Neonatal nutritional strategy of a viviparous elasmobranch with extremely low reproductive output

2020 ◽  
Vol 638 ◽  
pp. 107-121 ◽  
Author(s):  
BS Rangel ◽  
NE Hussey ◽  
Y Niella ◽  
LA Martinelli ◽  
AD Gomes ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Reproductive Strategies ◽  
Trophic Ecology ◽  
Essential Fatty Acids ◽  
Physiological State ◽  
Maternal Investment ◽  
Early Life History ◽  
Nutritional State ◽  
Disc Width ◽  
Biomarker Analysis

Throughout evolutionary history, elasmobranchs have developed diverse reproductive strategies. Little focused work, however, has addressed how neonatal nutritional state is affected by differing degrees of maternal investment associated with these markedly different reproductive strategies. To investigate the effect of maternal investment on the nutritional quality of pups during the early life history of an extremely viviparous elasmobranch, quantitative biomarker analysis including lipids, fatty acids and stable isotopes was conducted. Using the cownose ray Rhinoptera bonasus (histotrophic viviparous) as a model, we found that pups were initially born in a positive nutritional state, enriched in physiologically important essential fatty acids and nitrogen and carbon stable isotope values (δ15N and δ13C), a result of maternal intrauterine transfer. A systematic decrease in some fatty acids and δ15N values, as well as a decrease in cholesterol with growth, confirmed that these substrates were derived from maternal resources and used in initial metabolic processes following birth. An observed increase in condition factor, plasma essential fatty acids and triglyceride:cholesterol ratio with increasing body size identified a progression towards successful independent foraging with pups not displaying marked nutritional deficiency or fasting phases. Our multi-tracer approach allowed the identification of 2 size classes of young rays (<50 and <70 cm disc width) that displayed distinct physiological states. Since prenatal maternal investment is critical for offspring condition and to promote successful foraging post birth, understanding the trophic ecology and physiological state of pups during their first year is critical to guide management and conservation within nursery grounds.

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