Uterine and eggshell structure and histochemistry in a lizard with prolonged uterine egg retention (Lacertilia, Scincidae, Saiphos)

2010 ◽  
Vol 271 (11) ◽  
pp. 1342-1351 ◽  
Author(s):  
James R. Stewart ◽  
Ashley N. Mathieson ◽  
Tom W. Ecay ◽  
Jacquie F. Herbert ◽  
Scott L. Parker ◽  
...  
Keyword(s):  
Egg Retention ◽  
Eggshell Structure

scholarly journals The formation of a hatching line in the serosal cuticle confers multifaceted adaptive functions on the eggshell of a cicada

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Minoru Moriyama ◽  
Kouji Yasuyama ◽  
Hideharu Numata
Keyword(s):  
Protective Role ◽  
Terminal Phase ◽  
Embryonic Diapause ◽  
Insect Eggs ◽  
Ridge Structure ◽  
Conflicting Demands ◽  
Partial Degradation ◽  
Egg Period ◽  
Eggshell Structure

AbstractInsect eggshells must meet various demands of developing embryos. These demands sometimes conflict with each other; therefore, there are tradeoffs between eggshell properties, such as robustness and permeability. To meet these conflicting demands, particular eggshell structures have evolved in diverse insect species. Here, we report a rare eggshell structure found in the eggshell of a cicada, Cryptotympana facialis. This species has a prolonged egg period with embryonic diapause and a trait of humidity-inducible hatching, which would impose severe demands on the eggshell. We found that in eggs of this species, unlike many other insect eggs, a dedicated cleavage site, known as a hatching line, was formed not in the chorion but in the serosal cuticle. The hatching line was composed of a fine furrow accompanied by ridges on both sides. This furrow-ridge structure formed in the terminal phase of embryogenesis through the partial degradation of an initially thick and nearly flat cuticle layer. We showed that the permeability of the eggshell was low in the diapause stage, when the cuticle was thick, and increased with degradation of the serosal cuticle. We also demonstrated that the force required to cleave the eggshell was reduced after the formation of the hatching line. These results suggest that the establishment of the hatching line on the serosal cuticle enables flexible modification of eggshell properties during embryogenesis, and we predict that it is an adaptation to maximize the protective role of the shell during the long egg period while reducing the barrier to emerging nymphs at the time of hatching.

Eggshell structure, mode of development and growth rate in birds

Zoology ◽  
2008 ◽  
Vol 111 (6) ◽  
pp. 494-502 ◽  
Author(s):  
Ola Karlsson ◽  
Clas Lilja
Keyword(s):  
Growth Rate ◽  
Mode Of Development ◽  
Eggshell Structure

Egg retention as risk-spreading in Trichogramma

2007 ◽  
Vol 148 (3) ◽  
pp. 340
Author(s):  
Sergey Reznik ◽  
Nina Vaghina ◽  
Natalia Voinovich ◽  
Svetlana Karpova
Keyword(s):  
Egg Retention ◽  
Risk Spreading

Differential response to oviposition site by feral and domestic populations of Aedes aegypti (L.) (Diptera: Culicidae)

1978 ◽  
Vol 68 (3) ◽  
pp. 455-463 ◽  
Author(s):  
Sister M. G. Leahy ◽  
R. C. VandeHey ◽  
K. S. Booth
Keyword(s):  
Aedes Aegypti ◽  
Chemical Constituents ◽  
Differential Response ◽  
Oviposition Site ◽  
Laboratory Procedure ◽  
High Fecundity ◽  
Egg Retention ◽  
Feral Population ◽  
Phenotype Characteristic ◽  
Visual Attraction

AbstractLow fecundity in the laboratory was found in populations of Aedes aegypti (L.) exhibiting Black tergite (Bt), a phenotype characteristic of the feral A. a. formosus (Wlk), whereas high fecundity was found in six domestic populations of A. a. aegyptiin which the phenotype was absent. An investigation of the cause of low oviposition by the feral population indicated that behavioural differences in mating and feeding were not responsible; egg retention was identified as the major factor. Introduction into laboratory procedure of a variable simulating the feral environment, i.e., coconut-shell infusion at the oviposition site, induced a highly significant increase in feral fecundity both through its chemical constituents and visual attraction. Differential response to oviposition site is discussed in relation to the evolution of subspecies of A. aegypti.

Fecundity and Egg Retention of Some Sockeye Salmon (Oncorhynchus nerka) Stocks in British Columbia

1986 ◽  
Vol 43 (8) ◽  
pp. 1643-1655 ◽  
Author(s):  
J. I. Manzer ◽  
I. Miki
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Absolute Fecundity ◽  
Egg Retention ◽  
Inadequate Sample Size ◽  
Egg Number ◽  
The Mean ◽  
The Relationship ◽  
Individual Fecundity

The fecundity and egg retention of anadromous female sockeye salmon (Oncorhynchus nerka) collected during 1971–82 from several stocks in British Columbia undergoing controlled fertilization to enhance adult sockeye production were examined. The relationship between egg number and postorbital–hypural length based on 863 females representing 14 stocks was not consistent between all age-types, stocks, and years, probably because of inadequate sample size in some instances. Combined samples, however, revealed a significant positive relationship between postorbital–hypural length and egg number for age 1.2, 1.3, and 2.2 females. Mean absolute fecundity for the respective age-types was 3218, 4125, and 3544 eggs. For samples of 10 or more females, significant stock and annual differences were detected when individual mean absolute fecundity was adjusted to a postorbital–hypural length of 447 mm, but not for females of different age. A comparison of mean fecundities for coastal stocks with historical data for interior British Columbia stocks suggests that coastal stocks are 18% more fecund than interior stocks. Possible causal mechanisms for this regional difference are hypothesized. Examination of 796 carcasses (representing five stocks) for egg retention revealed a range from totally spawned to totally unspawned females, with 56% of the carcasses containing 20 eggs or less and 68% containing 50 eggs or less. The mean egg retention based on all samples combined was estimated to be 6.5% of the mean individual fecundity. This value was reduced to 3.9% when stock means were averaged.

scholarly journals A study of the time course of egg retention activity in the rabbit oviduct

Reproduction ◽  
1977 ◽  
Vol 50 (1) ◽  
pp. 69-73 ◽  
Author(s):  
C. V. Gomez ◽  
H. B. Croxatto
Keyword(s):  
Time Course ◽  
Egg Retention

scholarly journals Egg retention and intrauterine embryonic development in Sceloporus aeneus (Reptilia: Phrynosomatidae): implications for the evolution of viviparity

2012 ◽  
Vol 83 (3) ◽  
Author(s):  
Rodolfo García-Collazo ◽  
Maricela Villagrán-Santa Cruz ◽  
Eduardo Morales-Guillaumin ◽  
Rubi Nelsi Meza-Lázaro ◽  
Fausto R. Méndez-de la Cruz
Keyword(s):  
Embryonic Development ◽  
Egg Retention

Carbohydrate Suppresses Parasitization and Induces Egg Retention in Trichogramma

1997 ◽  
Vol 7 (2) ◽  
pp. 271-274 ◽  
Author(s):  
S. YA. REZNIK ◽  
N. D. VOINOVICH ◽  
T. YA. UMAROVA
Keyword(s):  
Egg Retention

Lowering body temperature induces embryonic diapause during prolonged egg retention in the lizard, Calotes versicolor

2002 ◽  
Vol 90 (1) ◽  
pp. 33-35 ◽  
Author(s):  
Bhagyashri A. Shanbhag ◽  
Srinivas K. Saidapur ◽  
Rajkumar S. Radder
Keyword(s):  
Body Temperature ◽  
Embryonic Diapause ◽  
Egg Retention ◽  
Calotes Versicolor
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