scholarly journals A new case of communal egg-laying by iguanas and American crocodiles (Crocodylus acutus Cuvier, 1807) from a Caribbean atoll of Mexico

2021 ◽  
pp. 1-5
Author(s):  
Pierre Charruau ◽  
Axel Rissac ◽  
David A. Macías Diaz
Keyword(s):  
Egg Laying ◽  
Crocodylus Acutus

Nesting ecology of the American crocodile in La Encrucijada Biosphere Reserve, Mexico

2016 ◽  
Vol 37 (3) ◽  
pp. 261-271 ◽  
Author(s):  
Giovany A. González-Desales ◽  
Octavio Monroy-Vilchis ◽  
Martha M. Zarco-González ◽  
Pierre Charruau
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Incubation Temperature ◽  
Biosphere Reserve ◽  
Reproductive Traits ◽  
Egg Laying ◽  
Anthropogenic Factors ◽  
Nesting Ecology ◽  
Crocodylus Acutus ◽  
American Crocodile

Nesting of the American crocodile (Crocodylus acutus) is affected by natural and anthropogenic processes. In Mexico, few studies exist on reproductive traits of wild populations. We assessed the key reproductive characteristics ofC. acutusin the La Encrucijada biosphere reserve and the environmental and anthropogenic factors that influence them. From February to June 2014, we searched for nests in the reserve. Clutch incubation temperature was recorded by data loggers and climatic variables were obtained from La Encrucijada meteorological station. Additionally, outside the study area, net primary productivity was obtained for different sites in Mexico to relate it to clutch characteristics. We found 34 nests in nine nesting areas. Egg laying occurred in March, and hatching took place from mid-May to early June. Mean clutch and eggs characteristics are among the higher reported forC. acutus. Some egg attributes had a relationship with the net primary productivity. There was no relation between hatching success and external and internal characteristics of the nest. A high percentage of nests was poached (50%) mainly for egg consumption and fear of crocodiles, and the nests closer to the river, trees or human settlements are more likely to be poached.

Erysipelas in egg-laying chickens: Clinical, pathological and bacteriological investigations

1975 ◽  
Vol 4 (1) ◽  
pp. 59-71 ◽  
Author(s):  
M. Bisgaard ◽  
P. Olsen
Keyword(s):  
Egg Laying

Experimental increase in female mass during the fertile phase leads to enhanced extra-pair paternity in pied flycatchers Ficedula hypoleuca

2019 ◽  
Author(s):  
Mireia Plaza ◽  
Alejandro Cantarero ◽  
Juan Moreno
Keyword(s):  
Negative Relationship ◽  
Ficedula Hypoleuca ◽  
Egg Laying ◽  
Female Dominance ◽  
Laying Date ◽  
Control Group ◽  
Wing Loading ◽  
Potential Fecundity ◽  
Fertile Phase ◽  
Extra Pair Paternity

Female mass in most altricial birds reaches its maximum during breeding at egg-laying, which coincides temporally with the fertile phase when extra-pair paternity (EPP) is determined. Higher mass at laying may have two different effects on EPP intensity. On the one hand, it would lead to increased wing loading (body mass/wing area), which may impair flight efficiency and thereby reduce female’s capacity to resist unwanted extra-pair male approaches (sexual conflict hypothesis). On the other hand, it would enhance female condition, favouring her capacity to evade mate-guarding and to search for extra-pair mates (female choice hypothesis). In both cases, higher female mass at laying may lead to enhanced EPP. To test this prediction, we reduced nest building effort by adding a completely constructed nest in an experimental group of female pied flycatchers (Ficedula hypoleuca). Our treatment caused an increase in mass and thereby wing loading and this was translated into a significantly higher EPP in the manipulated group compared with the control group as expected. There was also a significant negative relationship between EPP and laying date and the extent of the white wing patch, an index of female dominance. More body reserves at laying mean not only a higher potential fecundity but a higher level of EPP as well. This interaction had not previously received due attention but should be considered in future studies of avian breeding strategies.

Elevated nest predation risk promotes offspring size variation in birds with prolonged parental care.

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Predation Risk ◽  
Reproductive Cycle ◽  
Perceived Risk ◽  
Nest Predation ◽  
Bird Species ◽  
Size Variation ◽  
Egg Laying ◽  
Offspring Size ◽  
Natural Predation ◽  
Risk Spreading

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.

Autumn Migration of Waders (Charadrii) at the Reda Mouth (N Poland)

Ring ◽  
2009 ◽  
Vol 31 (1) ◽  
pp. 23-39 ◽  
Author(s):  
Włodzimierz Meissner ◽  
Anna Włodarczak-Komosińska ◽  
Dariusz Górecki ◽  
Cezary Wójcik ◽  
Mateusz Ściborski ◽  
...  
Keyword(s):  
Migration Pattern ◽  
Egg Laying ◽  
Autumn Migration ◽  
Tundra Zone ◽  
Age Classes ◽  
Calidris Alpina ◽  
Mouth Region ◽  
Baltic Coast ◽  
Northern Latitudes ◽  
Vanellus Vanellus

Autumn Migration of Waders (Charadrii) at the Reda Mouth (N Poland) The migration of waders was investigated at the Reda mouth (Polish Baltic coast) between 1996 and 2001. During the study 496 counts were conducted in the period between 5 July and 5 October. The most numerous species observed were: the Lapwing (Vanellus vanellus) - 39.5% and Dunlin (Calidris alpina) - 29.8% of all waders. Because of a variety of habitats in the Reda mouth region, among the waders staging numerously in the Reda mouth there were species typical both for coastal and inland habitat. It was shown that birds from tundra zone migrated later than those from more southern breeding areas, which was caused by much later beginning of egg laying in northern latitudes. Moreover, in the species from tundra zone, e.g. the Knot (Calidris canutus), Little Stint (C. minuta), Curlew Sandpiper (C. ferruginea), the migration of both age classes were well separated, whereas in those from more southern areas, e.g. the Little Ringed Plover (Charadius dubius), Common Sandpiper (Actitis hypoleucos), such difference was less pronounced and the period of common passage of adults and juveniles was much longer. A comparison of the obtained data on migration pattern with some other sites in Poland where regular counts were conducted showed several similarities and some discrepancies, which are discussed in the paper.

Structure-Reactivity Relationships on Substrates and Inhibitors of the Lysine Deacylase Sirtuin 2 from Schistosoma Mansoni (SmSirt2)

2019 ◽  
Author(s):  
Daria Monaldi ◽  
Dante Rotili ◽  
Julien Lancelot ◽  
Martin Marek ◽  
Nathalie Wössner ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Human Cancer ◽  
Egg Laying ◽  
Human Cancer Cells ◽  
Parasite Survival ◽  
Survival And Reproduction ◽  
Emergence Of Resistance ◽  
First Time ◽  
Parasitic Life Cycle

The only drug for treatment of Schistosomiasis is Praziquantel, and the possible emergence of resistance makes research on novel therapeutic agents necessary. Targeting of Schistosoma mansoni epigenetic enzymes, which regulate the parasitic life cycle, emerged as promising approach. Due to the strong effects of human Sirtuin inhibitors on parasite survival and reproduction, Schistosoma sirtuins were postulated as therapeutic targets. In vitro testing of synthetic substrates of S. mansoni Sirtuin 2 (SmSirt2) and kinetic experiments on a myristoylated peptide demonstrated lysine long chain deacylation as an intrinsic SmSirt2 activity for the first time. Focused in vitro screening of the GSK Kinetobox library and structure-activity relationships (SAR) of identified hits, led to the first SmSirt2 inhibitors with activity in the low micromolar range. Several SmSirt2 inhibitors showed potency against both larval schistosomes (viability) and adult worms (pairing, egg laying) in culture without general toxicity to human cancer cells.<br>

Effect of Poliroli microelements on the efficiency of egg laying, egg quality and prevention of diseases of the reproductive organs of laying hens

2020 ◽  
Vol 23 (08) ◽  
pp. 41-44
Author(s):  
S.V. Fedotov ◽  
◽  
S.V. Redkin ◽  
N.S. Belozertseva ◽  
◽  
...  
Keyword(s):  
Laying Hens ◽  
Egg Quality ◽  
Reproductive Organs ◽  
Egg Laying

Preliminary study of DDTs variability depending on the egg-laying order of Black-tailed Gull (Larus crassirostris) breeding at Baengnyeongdo, South Korea

2017 ◽  
Vol 24 (2) ◽  
pp. 41-51 ◽  
Author(s):  
Jangho Lee ◽  
Jongchun Lee ◽  
Heeyeon Jang ◽  
Jong-Hyouk Park ◽  
Kyuyoung Shim
Keyword(s):  
South Korea ◽  
Egg Laying ◽  
Laying Order ◽  
Preliminary Study
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