Effect of sand granulometry on the egg hatchling success of the sea turtle Caretta caretta

The environmental characteristics of nesting sites of sea turtles may directly interfere with the egg hatchling success. The objective of the present study was to evaluate the factors that affect the success of hatchling in the nests of the loggerhead sea turtle (Caretta caretta). Data from 37 nests of C. caretta from the coast of Mata de São João, Bahia, northeastern Brazil, were obtained from TAMAR, Sauípe station. Samples of sand were collected in each nest to determine the granulometry. A significant negative relationship was found between the stillborn rate and the fine sand ratio (r2 = 0.119; p = 0.036), indicating that a larger fraction of fine sand had a positive effect on nest hatchling success. The egg laying date also had a significant influence on the rate of stillbirths (r2 = 0.163; p = 0.013), with a trend towards a higher stillbirth rate, the later the laying date of the eggs. There is indication that the transfer of eggs to sites with more favorable characteristics may be considered as a potential alternative to increase the hatchling success rate of C. caretta eggs.

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TAPHONOMY OF EXTANT DESERT TORTOISE (GOPHERUS AGASSIZII) AND LOGGERHEAD SEA TURTLE (CARETTA CARETTA) NESTING SITES: IMPLICATIONS FOR INTERPRETING THE FOSSIL RECORD

Palaios ◽

10.2110/palo.2014.048 ◽

2015 ◽

Vol 30 (3) ◽

pp. 207-223 ◽

Cited By ~ 10

Author(s):

F. D. JACKSON ◽

D. J. VARRICCHIO ◽

R. A. JACKSON ◽

A. D. WALDE ◽

G. A. BISHOP

Keyword(s):

Fossil Record ◽

Caretta Caretta ◽

Sea Turtle ◽

Gopherus Agassizii ◽

Desert Tortoise ◽

Loggerhead Sea Turtle ◽

Nesting Sites

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

10.32942/osf.io/qrnkb ◽

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.

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