Although sexual stereotypes paint males as being promiscuous and females as being choosy in order to increase their reproductive success, multiple mating by females is widespread and females of many taxa often produce progeny sired by multiple males – but why? In species in which there are no direct benefits associated with mating, females may adopt promiscuous mating strategies to increase their fitness through the acquisition of genetic benefits. Here, I examine the genetic mating system of map turtles, Graptemys geographica in Lake Opinicon. Based on the most conservative estimate, at least 71% of clutches in this population are sired by multiple males. There did not appear to be any relationship between female body size and frequency of multiple paternity. There was a marginally significant effect of multiple paternity on hatching success and survival of clutches, but there was no effect on hatchling morphology or locomotor performance.

Although sexual stereotypes paint males as being promiscuous and females as being choosy in order to increase their reproductive success, multiple mating by females is widespread and females of many taxa often produce progeny sired by multiple males – but why? In species in which there are no direct benefits associated with mating, females may adopt promiscuous mating strategies to increase their fitness through the acquisition of genetic benefits. Here, I examine the genetic mating system of map turtles, Graptemys geographica in Lake Opinicon. Based on the most conservative estimate, at least 71% of clutches in this population are sired by multiple males. There did not appear to be any relationship between female body size and frequency of multiple paternity. There was a marginally significant effect of multiple paternity on hatching success and survival of clutches, but there was no effect on hatchling morphology or locomotor performance.

Although sexual stereotypes paint males as being promiscuous and females as being choosy in order to increase their reproductive success, multiple mating by females is widespread and females of many taxa often produce progeny sired by multiple males – but why? In species in which there are no direct benefits associated with mating, females may adopt promiscuous mating strategies to increase their fitness through the acquisition of genetic benefits. Here, I examine the genetic mating system of map turtles, Graptemys geographica in Lake Opinicon. Based on the most conservative estimate, at least 71% of clutches in this population are sired by multiple males. There did not appear to be any relationship between female body size and frequency of multiple paternity. There was a marginally significant effect of multiple paternity on hatching success and survival of clutches, but there was no effect on hatchling morphology or locomotor performance.

No description available.

No description available.

Neonatal painted turtles (Chrysemys picta) spend their first winter inside the shallow, subterranean nest cavity where they completed embryogenesis. Consequently, hatchlings at high latitudes may be exposed to ice and cold during the winter. This study was undertaken to determine how long hatchlings withstand freezing at temperatures slightly below 0°C because tolerance for freezing has been proposed to be the key to survival by overwintering animals. A thermocouple was glued to the carapace of each hatchling. The animal was dipped in water to provide a site of nucleation of ice and was then placed into a glass jar that was partially immersed in a circulating bath at -2°C. Carapace temperature was monitored throughout the procedure. When a freezing exotherm was detected, timing of the freezing event began. Animals were maintained in a frozen state for 12-48 h prior to being warmed to room temperature. Of the 39 hatchlings, 22 did not survive, and mortality increased as the duration of freezing increased. Logistic regression indicates that no turtle would have survived in a frozen state for more than 54 h. These results indicate that hatchlings can survive only brief exposure to freezing of the body fluids. Thus, hatchlings cannot tolerate freezing during prolonged periods of cold.

No description available.

Realizaram-se dois experimentos com o objetivo de avaliar os efeitos da nutrição pós-eclosão em frangos de corte. No primeiro experimento avaliaram-se o efeito do tempo de fornecimento da dieta pré-inicial (DPI) nas características histomorfométricas do duodeno (CHD), em parâmetros de desempenho (PDES), de rendimento de carcaça (RC) até os 49 dias de idade. Foram utilizadas 960 aves distribuídas em delineamento inteiramente casualizado em esquema fatorial 2x4 (2 pesos de pintainhos - até 42 gramas e acima de 45 gramas; 4 tempos de fornecimento da DPI - 0, 1 a 7 dias, 1 a 10 dias e 1 a 14 dias), totalizando 8 tratamentos com 5 repetições de 30 aves cada. No segundo experimento avaliaram-se o tempo para alojamento e o fornecimento de suplementos pós-eclosão (SPO) para pintainhos com diferentes pesos à eclosão, na atividade mitótica de células satélites da musculatura peitoral, na alometria dos órgãos do trato gastrintestinal (TGI), em CHD, em PDES, e RC até os 42 dias de idade. Foram utilizadas 1.280 aves distribuídas em delineamento inteiramente casualizado em esquema fatorial 2x2x2 (2 pesos dos pintainhos à eclosão: até 44g e acima de 48g; 2 SPO: 1 suplemento com 8% PB e 16% carboidratos - SPO 8/16 - e 1 suplemento com 10% PB e 20% de carboidratos - SPO 10/20 - ; 2 períodos de fornecimento dos SPO: 24 e 48h), totalizando 8 tratamentos com 4 repetições de 40 aves cada. Adicionalmente, foram alojadas 160 aves da mesma linhagem, que apresentavam peso médio de 49g à eclosão, e foram submetidas a um período de jejum de 24h, sendo que as mesmas provinham do mesmo lote de matrizes das aves submetidas aos tratamentos supracitados. Os animais de ambos os experimentos foram submetidas a programas alimentares que compreenderam três ou quatro fases (préinicial e/ou inicial; engorda; final), sendo as dietas formuladas a base de milho e farelo de soja. Os dados obtidos foram analisados com auxílio do procedimento GLM do software estatístico SAS, e as médias comparadas pelo teste de Tukey ao nível de 5% de probabilidade. Para o presente estudo, o peso dos pintainhos ao alojamento/eclosão causou efeito significativo no desempenho dos animais, sendo que animais mais pesados apresentaram peso vivo superior, apesar de terem apresentado menores alturas de vilosidade. Observou-se que o fornecimento da DPI por um período de 7 dias, causou efeito benéfico no desempenho dos animais, acarretando, entretanto, numa diminuição no RC das aves. Pintainhos mantidos em jejum por um período de 24h demonstraram um melhor desenvolvimento do TGI no período pós-eclosão, permitindo que estas aves apresentassem crescimento compensatório. O fornecimento de SPO demonstrou ser eficaz em reduzir a perda de peso dos animais no período pré-alojamento, sendo que o oferecimento do SPO 10/20 mostrou ser mais vantajoso, devido ao fato do mesmo ter causado efeitos benéficos nas CHD, e também um aumento no rendimento de filé de peito. Entretanto, deve-se priorizar o fornecimento dos SPO pelo menor período possível, já que os mesmos não são capazes de suprir de maneira adequada às exigências nutricionais das aves recém-eclodidas. / It were performed two experiments with the aim of evaluate the effects of posthatch nutrition of broiler chickens. In the first trial were evaluated the effects of feeding a pre-starter diet (PSD) on duodenal morphology (DM), live performance (LP), and carcass yield (CY). Nine hundred and sixty day-old male Cobb-500 broiler, with two different weights at housing (until 42 g and more than 45 g) were placed in 32 floor pens, and then submitted to four different periods of feeding a PSD (0, 1 to 7 days, 1 to 10 days and 1 to 14 days), totalizing 8 treatments with 4 replications of 30 birds each. In the second trial were evaluated the effects of feeding different hatchling supplements (HS) for different periods on breast muscle satellite cell mitotic activity (SCMA), alometric growth of digestive organs, DM, LP, and CY of broiler chickens up to 42 days. One thousand and two hundred and eighty day-old male Cobb-500 broiler were used on a 2x2x2 factorial study (two different weights at hatch :until 44 g and more than 49 g; two HS: 8% of crude protein and 16% of carbohydrates - HS 8/16 - or 10% of crude protein and 20% of carbohydrates - HS 10/20; two feeding periods of HS: 24 or 48h), totalizing 8 treatments with 4 replications of 40 birds each. Additionally, it were housed 160 male chicks from the same broiler breeder flock, of 49g of mean weight at hatch, which were submitted to 24h fasting prior to placement. The animals of both experiments were fed with basal corn-soy pre-starter/starter/grower/finisher diets. All data were analyzed using SAS\'s GLM procedures, and significance were measured at p<0,05 using Tukey\'s multiple range test to determine differences between treatments means. Overall, heavier birds at hatch/housing caused significative effect on LP, presenting decreased villus height, and an increased body weight. The birds that were fed with the PSD up to 7 days presented an increased LP, and a smaller CY. Chicks which were fasted for 24h presented a better development of DM on the post-hatch period, showing a compensatory growth. Both HS were efficient on minimize the chick\'s weight loss prior to placement, however birds that were fed with 10/20 HS showed satisfactory effects not only on DM but also an increased breast meat yield. However, the period of feeding of HS should be as small as possible, because this supplement is not capable to supply efficiently the nutritional requirements of newly hatched chicks.

Realizaram-se dois experimentos com o objetivo de avaliar os efeitos da nutrição pós-eclosão em frangos de corte. No primeiro experimento avaliaram-se o efeito do tempo de fornecimento da dieta pré-inicial (DPI) nas características histomorfométricas do duodeno (CHD), em parâmetros de desempenho (PDES), de rendimento de carcaça (RC) até os 49 dias de idade. Foram utilizadas 960 aves distribuídas em delineamento inteiramente casualizado em esquema fatorial 2x4 (2 pesos de pintainhos - até 42 gramas e acima de 45 gramas; 4 tempos de fornecimento da DPI - 0, 1 a 7 dias, 1 a 10 dias e 1 a 14 dias), totalizando 8 tratamentos com 5 repetições de 30 aves cada. No segundo experimento avaliaram-se o tempo para alojamento e o fornecimento de suplementos pós-eclosão (SPO) para pintainhos com diferentes pesos à eclosão, na atividade mitótica de células satélites da musculatura peitoral, na alometria dos órgãos do trato gastrintestinal (TGI), em CHD, em PDES, e RC até os 42 dias de idade. Foram utilizadas 1.280 aves distribuídas em delineamento inteiramente casualizado em esquema fatorial 2x2x2 (2 pesos dos pintainhos à eclosão: até 44g e acima de 48g; 2 SPO: 1 suplemento com 8% PB e 16% carboidratos - SPO 8/16 - e 1 suplemento com 10% PB e 20% de carboidratos - SPO 10/20 - ; 2 períodos de fornecimento dos SPO: 24 e 48h), totalizando 8 tratamentos com 4 repetições de 40 aves cada. Adicionalmente, foram alojadas 160 aves da mesma linhagem, que apresentavam peso médio de 49g à eclosão, e foram submetidas a um período de jejum de 24h, sendo que as mesmas provinham do mesmo lote de matrizes das aves submetidas aos tratamentos supracitados. Os animais de ambos os experimentos foram submetidas a programas alimentares que compreenderam três ou quatro fases (préinicial e/ou inicial; engorda; final), sendo as dietas formuladas a base de milho e farelo de soja. Os dados obtidos foram analisados com auxílio do procedimento GLM do software estatístico SAS, e as médias comparadas pelo teste de Tukey ao nível de 5% de probabilidade. Para o presente estudo, o peso dos pintainhos ao alojamento/eclosão causou efeito significativo no desempenho dos animais, sendo que animais mais pesados apresentaram peso vivo superior, apesar de terem apresentado menores alturas de vilosidade. Observou-se que o fornecimento da DPI por um período de 7 dias, causou efeito benéfico no desempenho dos animais, acarretando, entretanto, numa diminuição no RC das aves. Pintainhos mantidos em jejum por um período de 24h demonstraram um melhor desenvolvimento do TGI no período pós-eclosão, permitindo que estas aves apresentassem crescimento compensatório. O fornecimento de SPO demonstrou ser eficaz em reduzir a perda de peso dos animais no período pré-alojamento, sendo que o oferecimento do SPO 10/20 mostrou ser mais vantajoso, devido ao fato do mesmo ter causado efeitos benéficos nas CHD, e também um aumento no rendimento de filé de peito. Entretanto, deve-se priorizar o fornecimento dos SPO pelo menor período possível, já que os mesmos não são capazes de suprir de maneira adequada às exigências nutricionais das aves recém-eclodidas. / It were performed two experiments with the aim of evaluate the effects of posthatch nutrition of broiler chickens. In the first trial were evaluated the effects of feeding a pre-starter diet (PSD) on duodenal morphology (DM), live performance (LP), and carcass yield (CY). Nine hundred and sixty day-old male Cobb-500 broiler, with two different weights at housing (until 42 g and more than 45 g) were placed in 32 floor pens, and then submitted to four different periods of feeding a PSD (0, 1 to 7 days, 1 to 10 days and 1 to 14 days), totalizing 8 treatments with 4 replications of 30 birds each. In the second trial were evaluated the effects of feeding different hatchling supplements (HS) for different periods on breast muscle satellite cell mitotic activity (SCMA), alometric growth of digestive organs, DM, LP, and CY of broiler chickens up to 42 days. One thousand and two hundred and eighty day-old male Cobb-500 broiler were used on a 2x2x2 factorial study (two different weights at hatch :until 44 g and more than 49 g; two HS: 8% of crude protein and 16% of carbohydrates - HS 8/16 - or 10% of crude protein and 20% of carbohydrates - HS 10/20; two feeding periods of HS: 24 or 48h), totalizing 8 treatments with 4 replications of 40 birds each. Additionally, it were housed 160 male chicks from the same broiler breeder flock, of 49g of mean weight at hatch, which were submitted to 24h fasting prior to placement. The animals of both experiments were fed with basal corn-soy pre-starter/starter/grower/finisher diets. All data were analyzed using SAS\'s GLM procedures, and significance were measured at p<0,05 using Tukey\'s multiple range test to determine differences between treatments means. Overall, heavier birds at hatch/housing caused significative effect on LP, presenting decreased villus height, and an increased body weight. The birds that were fed with the PSD up to 7 days presented an increased LP, and a smaller CY. Chicks which were fasted for 24h presented a better development of DM on the post-hatch period, showing a compensatory growth. Both HS were efficient on minimize the chick\'s weight loss prior to placement, however birds that were fed with 10/20 HS showed satisfactory effects not only on DM but also an increased breast meat yield. However, the period of feeding of HS should be as small as possible, because this supplement is not capable to supply efficiently the nutritional requirements of newly hatched chicks.