In altricial and semi-altricial species, asynchronous hatching gives the first chicks to hatch an initial advantage over other siblings and often leads to the elimination of the smallest chicks. Both baseline corticosterone and acute stress-induced corticosterone levels have been shown to be higher in food deprived chicks than in chicks fed ad libitum. However, first-hatched chicks have also be...

Hatching asynchrony in avian species generally leads to a size hierarchy among siblings, favouring the first-hatched chicks. Maternally deposited hormones affect the embryo and chick's physiology and behaviour. It has been observed that progesterone, a hormone present at higher levels than other steroid hormones in egg yolks, is negatively related to body mass in embryos, chicks and adults. A d...

We tested the hypothesis that mother birds counterbalance the negative effects of hatching asynchrony for later-hatched chicks by increasing the yolk androgen concentrations in consecutive eggs of their clutch. In doing so, they may adaptively tune each offspring's competitive ability and, thus, growth and survival. However, evidence in support of this hypothesis is contradictory. The yolk conc...

Chick embryo tissues contain a high proportion of highly polyunsaturated fatty acids in the lipid fraction and therefore need antioxidant defence (Surai, 1999). It is well accepted that maternal diet composition is a major determinant of antioxidant system development during embryogenesis and in early postnatal development. The antioxidant system of the newly hatched chick includes the fat-solu...

ABSTRACT We reared field-collected egg masses of the caddisflies Phylloicus amazonas (n = 2) and elektoros 7) to adulthood. First instar larvae both species hatched up five days after field collection. Median development time from first larval adult was 229 for P. 275 elektoros, including pupal (median 13.5 16 days, respectively). Shredder organisms have been used frequently in studies related ...

Egg viability, hatchability, and development are significant factors in the natural silk industry. Life cycle modification is an important aspect that must be considered to perform effective efficient mass-rearing quality control. This study aimed improve mass rearing efficiency of Samia chintya ricini through a life technique by refrigeration. The was conducted storing S. c. eggs refrigerator ...

the present study was designed to investigate the prevalence of salmonella species, their molecular characterization and antibiotic resistance in backyard chickens. a total of 1125 samples were collected from backyard chickens in two consequent samplings. in the first part, samples were included of 820 poor recently hatched chicks, hatching residuals, egg shells in the nest floor, cloacal swabs...

T h e infectivity of second-stage larvae of Meloidogyne spp. is a function of soil temperature, aeration, moisture, texture, and density, as well as a funct ion of the distance the second-stage larvae have to travel pr ior to root penetra t ion (3, 4). Because eggs may require up to 2 weeks to hatch under greenhouse conditions, infection periods with larvae are normal ly shorter than those with...

We examined the molecular basis of the circadian control of egg hatching behavior in the silkmoth Antheraea pernyi. Egg hatching is rhythmically gated, persists under constant darkness, and can be entrained by light by midembryogenesis. The time of appearance of photic entrainment by the silkmoth embryo coincides with the appearance of Period (PER) and Timeless (TIM) proteins in eight cells in ...

Experimental synchronization of onset of incubation was employed in laboratory held zebra finches Taeniopygia guttata to study whether differential resource allocation and possible bias of offspring sex in subsequent eggs in the laying order could mitigate the effects of hatching asynchrony. We found that egg mass increased with laying order, but offspring sex was not related to laying order. A...