scholarly journals THE RELATIONSHIP BETWEEN FEMALE SIZE AND EGG SIZE IN THE FRESHWATER CRAYFISH AUSTROPOTAMOBIUS TORRENTIUM

2005 ◽  
pp. 777-785 ◽  
Author(s):  
I. MAGUIRE ◽  
G. I.V. KLOBUČAR ◽  
R. ERBEN
Keyword(s):  
Egg Size ◽  
Female Size ◽  
Freshwater Crayfish ◽  
Austropotamobius Torrentium ◽  
The Relationship

Fecundity and Egg Size of a Brood Stock of Salvelinus fontinalis × S. namaycush Hybrids (Splake)

1974 ◽  
Vol 31 (2) ◽  
pp. 217-220 ◽  
Author(s):  
G. B. Ayles
Keyword(s):  
Egg Size ◽  
Lake Trout ◽  
Salvelinus Fontinalis ◽  
Lake Huron ◽  
Female Size ◽  
Brood Stock ◽  
Trout Population ◽  
Egg Diameter

Estimates of average egg diameter and average number of eggs per female from a brood stock of Salvelinus fontinalis × S. namaycush (splake) hybrids were 0.468 cm and 1169 eggs, respectively. Variation in egg size between females was attributable to variation in both size and age of the fish, whereas differences in fecundity were attributed only to differences in female size. At a given size a splake had more and larger eggs than have been reported for lake trout. The significance of the findings is discussed in relation to the reestablishment of a viable trout population in Lake Huron.

scholarly journals Pipefish embryo oxygenation, survival, and development: egg size, male size, and temperature effects

2019 ◽  
Vol 30 (5) ◽  
pp. 1451-1460 ◽  
Author(s):  
Malin Nygård ◽  
Charlotta Kvarnemo ◽  
Ingrid Ahnesjö ◽  
Ines Braga Goncalves
Keyword(s):  
Egg Size ◽  
Care Quality ◽  
Offspring Size ◽  
Female Size ◽  
Male Size ◽  
Embryo Survival ◽  
Oxygen Levels ◽  
Syngnathus Typhle ◽  
Uniparental Care ◽  
Male Care

AbstractIn animals with uniparental care, the quality of care provided by one sex can deeply impact the reproductive success of both sexes. Studying variation in parental care quality within a species and which factors may affect it can, therefore, shed important light on patterns of mate choice and other reproductive decisions observed in nature. Using Syngnathus typhle, a pipefish species with extensive uniparental male care, with embryos developing inside a brood pouch during a lengthy pregnancy, we assessed how egg size (which correlates positively with female size), male size, and water temperature affect brooding traits that relate to male care quality, all measured on day 18, approximately 1/3, of the brooding period. We found that larger males brooded eggs at lower densities, and their embryos were heavier than those of small males independent of initial egg size. However, large males had lower embryo survival relative to small males. We found no effect of egg size or of paternal size on within-pouch oxygen levels, but oxygen levels were significantly higher in the bottom than the middle section of the pouch. Males that brooded at higher temperatures had lower pouch oxygen levels presumably because of higher embryo developmental rates, as more developed embryos consume more oxygen. Together, our results suggest that small and large males follow distinct paternal strategies: large males positively affect embryo size whereas small males favor embryo survival. As females prefer large mates, offspring size at independence may be more important to female fitness than offspring survival during development.

scholarly journals Acanthocephalan size and sex affect the modification of intermediate host colouration

Parasitology ◽  
2009 ◽  
Vol 136 (8) ◽  
pp. 847-854 ◽  
Author(s):  
D. P. BENESH ◽  
O. SEPPÄLÄ ◽  
E. T. VALTONEN
Keyword(s):  
Intermediate Host ◽  
Adaptive Strategy ◽  
Female Size ◽  
Larval Size ◽  
Male And Female ◽  
Establishment Success ◽  
Acanthocephalus Lucii ◽  
Host Mortality ◽  
Male Parasite ◽  
The Relationship

SUMMARYFor trophically transmitted parasites, transitional larval size is often related to fitness. Larger parasites may have higher establishment success and/or adult fecundity, but prolonged growth in the intermediate host increases the risk of failed transmission via natural host mortality. We investigated the relationship between the larval size of an acanthocephalan (Acanthocephalus lucii) and a trait presumably related to transmission, i.e. altered colouration in the isopod intermediate host. In natural collections, big isopods harboured larger worms and had more modified (darker) abdominal colouration than small hosts. Small isopods infected with a male parasite tended to have darker abdominal pigmentation than those infected with a female, but this difference was absent in larger hosts. Female size increases rapidly with host size, so females may have more to gain than males by remaining in and growing mutually with small hosts. In experimental infections, a large total parasite volume was associated with darker host respiratory operculae, especially when it was distributed among fewer worms. Our results suggest that host pigment alteration increases with parasite size, albeit differently for male and female worms. This may be an adaptive strategy if, as parasites grow, the potential for additional growth decreases and the likelihood of host mortality increases.

Benefits of fidelity: does host specialization impact nematode parasite life history and fecundity?

Parasitology ◽  
2013 ◽  
Vol 140 (5) ◽  
pp. 587-597 ◽  
Author(s):  
J. KOPRIVNIKAR ◽  
H. S. RANDHAWA
Keyword(s):  
Life History ◽  
Host Specificity ◽  
Egg Size ◽  
Host Specialization ◽  
Published Data ◽  
Female Size ◽  
Patent Period ◽  
Trade Offs ◽  
Evolutionary Level ◽  
Host Parasite

SUMMARYThe range of hosts used by a parasite is influenced by macro-evolutionary processes (host switching, host–parasite co-evolution), as well as ‘encounter filters’ and ‘compatibility filters’ at the micro-evolutionary level driven by host/parasite ecology and physiology. Host specialization is hypothesized to result in trade-offs with aspects of parasite life history (e.g. reproductive output), but these have not been well studied. We used previously published data to create models examining general relationships among host specificity and important aspects of life history and reproduction for nematodes parasitizing animals. Our results indicate no general trade-off between host specificity and the average pre-patent period (time to first reproduction), female size, egg size, or fecundity of these nematodes. However, female size was positively related to egg size, fecundity, and pre-patent period. Host compatibility may thus not be the primary determinant of specificity in these parasitic nematodes if there are few apparent trade-offs with reproduction, but rather, the encounter opportunities for new host species at the micro-evolutionary level, and other processes at the macro-evolutionary level (i.e. phylogeny). Because host specificity is recognized as a key factor determining the spread of parasitic diseases understanding factors limiting host use are essential to predict future changes in parasite range and occurrence.

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.

Can timing of spawning explain the increase in egg size with female size in salmonid fish?

2014 ◽  
Vol 24 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Pauliina Louhi ◽  
Grethe Robertsen ◽  
Ian A. Fleming ◽  
Sigurd Einum
Keyword(s):  
Egg Size ◽  
Salmonid Fish ◽  
Female Size ◽  
Timing Of Spawning
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