scholarly journals Egg production, population structure and biochemical composition of the subantarctic copepod Paraeuchaeta antarctica in the Kerguelen Archipelago

2000 ◽  
Vol 205 ◽  
pp. 207-217 ◽  
Author(s):  
F Alonzo ◽  
P Mayzaud ◽  
S Razouls
Keyword(s):  
Population Structure ◽  
Biochemical Composition ◽  
Egg Production ◽  
Kerguelen Archipelago

scholarly journals Forty-year natural history study of Bahalana geracei Carpenter, 1981, an anchialine cave-dwelling isopod (Crustacea, Isopoda, Cirolanidae) from San Salvador Island, Bahamas: reproduction, growth, longevity, and population structure

2021 ◽  
Vol 37 ◽  
pp. 105-156
Author(s):  
Jerry H. Carpenter
Keyword(s):  
Population Structure ◽  
Natural History ◽  
Egg Production ◽  
Natural History Study ◽  
San Salvador ◽  
Adult Growth ◽  
San Salvador Island ◽  
History Of ◽  
Female Longevity ◽  
Gravid Females

Almost nothing has been reported on the natural history of any of the world’s 92 species of cave cirolanids, including those from saltwater caves (anchialine). Over 1400 specimens of Bahalana geracei Carpenter, 1981 were collected in two caves from 1978–2018; size-frequency data provided insight into population structure. Some specimens were maintained alive over multiple years to study rarely reported activities for cave cirolanids: feeding, molting, growth, longevity, and reproduction. Photographs document these phenomena. Mating occurred after gravid females shed both halves of reproductive molts. Females can have multiple broods (iteroparous) with ~2.0–3.5 years per reproductive cycle: egg production (~9–24 months), mating, brooding (5–6 months), release of 6–55 mancas (2.3–3.3 mm long), and oostegite molt (~2–13 months after manca release). Estimated lifetime fecundity is 58 mancas per female; probable range is 20–120. In Lighthouse Cave, females outnumbered males (~4:1), grew larger (16.8 vs. 9.5 mm), and lived longer. Growth rates were slow: ~1–2 years for three instars of post-marsupial manca development (from ~2.3–4.0 mm); estimated adult growth rate was 0.8 mm/year (1.6 molts/year) for males, and 0.5 mm/year (1.5 molts/year) for females. Longevity estimates for females are 25–28 years with 23–30 instars, vs. 6–8 years for males with 13–15 instars. Males from Major’s Cave were nearly as numerous and as large (14.8 mm) as females; estimated longevity for males is >20 years. Longevity estimates of >20 years appear to be the longest for any isopod species. Female longevity probably increased by being starvation resistant, surviving multiple broods, cannibalizing smaller B. geracei, and living in a low-stress environment. Populations appear to be stable, relatively large, and not currently threatened.

scholarly journals Egg Composition in Relation to Female Age and Relaying: Constraints on Egg Production in Thick-Billed Murres (Uria Lomvia)

The Auk ◽  
2003 ◽  
Vol 120 (3) ◽  
pp. 645-657 ◽  
Author(s):  
J. Mark Hipfner ◽  
Anthony J. Gaston ◽  
Gene R. Herzberg ◽  
John T. Brosnan ◽  
Anne E. Storey
Keyword(s):  
Amino Acid ◽  
Biochemical Composition ◽  
Egg Production ◽  
Adult Survival ◽  
Laying Date ◽  
Egg Mass ◽  
Uria Lomvia ◽  
Protein Amino Acid ◽  
Shell Mass ◽  
Young Females

Abstract There is growing awareness that costs associated with egg production play a significant role in shaping avian life histories. The life-history strategy of the Thick-billed Murre (Uria lomvia), a colonial, cliff-breeding seabird of Arctic waters, is characterized by a high annual adult survival rate, deferred breeding, and laying of a single-egg clutch. The single-egg clutch is a widespread phenomenon among seabirds and is generally thought to reflect demands of chick provisioning, rather than egg production. We compared composition of eggs laid by Thick-billed Murres most likely to be physiologically constrained in their capacity to produce eggs (young females with no prior experience, and females forming replacement eggs) to that of first eggs laid by early laying females (typically older, more experienced members of the population). Young, inexperienced females laid 4–18 days past the populationwide median laying date, and their eggs averaged 13% lighter in mass than those laid by early layers. Compared to early laid eggs, shell mass on young females’ eggs was similar to that predicted from egg mass, but their eggs had a lower yolk-to-albumen ratio. There was little difference between the two groups in relative protein content of albumen, relative protein or lipid content of yolk, or amino acid makeup of protein in yolk or albumen. Replacement eggs averaged 6% lighter in mass than first eggs laid by the same females earlier that season. As with young females’ eggs, replacement eggs had shells similar in mass to that predicted from egg mass, but lower yolk-to-albumen ratios, when compared to early laid eggs. Both protein and lipid concentrations in yolk were similar in first and replacement eggs, but replacements were deficient in albumen protein. Amino acid makeup of protein in yolk and albumen was similar in the two groups. Those results suggest that any limitations on egg production acting on young, inexperienced females are manifested in delayed laying and reductions in overall egg mass and proportional yolk content, but not in variation in biochemical composition of their eggs. Limitations on females forming replacement eggs are manifested not only in reduced egg mass and yolk content (as with young females), but also in changes in the biochemical composition of eggs; in particular, evidence suggests that relaying females may face a deficit of endogenous protein. The existence of such limitations suggests that demands of egg production can be significant even in a species that lays a single-egg clutch.

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