The Cape porcupine Hystrix africaeaustralis is a large (12-18 kg) nocturnal hystricomorph rodent occurring throughout southern Africa where it is sometimes used as a source of food and often regarded as a nuisance by crop-producing fanners. They live in family groups, these generally comprising an adult male, adult female and varying numbers of offspring of successive litters. Reproduction is c...

the adrenal gland of notopterus notopterus (pallas) consisted of interrenal and chromaffin cells, distributed around the main branches of posterior cardinal vein in most anterior part of the pronephric kidney. seasonal histological characteristics of the interrenal and chromaffin cells in relation to testicular activity of n. notopterus were studied by adopting different staining techniques. th...

Understanding how phenotypic plasticity evolves and in turn affects the course of evolution is a major challenge in modern biology. By definition, biological species are reproductively isolated, but many animals fail to distinguish between conspecifics and closely related heterospecifics. In some cases, phenotypic plasticity may interfere with species recognition. Here, we document a seasonal p...

Seasonal change in the temperate and polar regions of Earth determines how the world looks around us and, in fact, how we live our day-to-day lives. For biological organisms, seasonal change typically involves complex physiological and metabolic reorganization, the majority of which is regulated by photoperiodism. Photoperiodism is the ability of animals and plants to use day length or night le...

The reproductive behavior and the seasonal occurrence of Psecas viridipurpureus were studied at the Estação Ecológica do Noroeste Paulista, a small conservation area in the northwest region of São Paulo State, Brazil (49 degrees 22'50"W and 20 degrees 48'36"S). P. viridipurpureus occurred on "gravatá", a bromeliaceous plant (Bromelia balansae, Bromeliaceae) which does not accumulate rain water....

The growth rate for infants and young children manifests the significant differences between age, sex, regional, and seasonal distributions. The growth rate for infants and young children is a complex process that depends on interaction of the genetic and environmental factors. All genetic and environmental factors jointly contribute to the growth rate for infants and young children, for exampl...

During summer and early fall, many sow farms experience a variety of reproductive problems, such as, anestrus, extended weaning-to-estrus intervals, poor conception rates, higher embryo mortality rates and low farrowing rates. This phenomenon is commonly referred to as “seasonal infertility” and can also be present in boar studs, where the result is lower semen output and lower semen quality. M...

Present study was designed to examine daily and seasonal variability in the innate immune responses of splenocytes in the fresh water snake, Natrix piscator. Animals were mildly anesthetized and spleen was aseptically isolated and processed for macrophage phagocytosis, NBT reduction, nitrite production, splenocyte proliferation and serum lysozyme activity. Samples were collected at seven time p...

Photoperiodic regulation of melatonin receptor types on target tissues, such as lymphatic organs, has never been explored for any seasonal breeder. In the present study, we accessed the high affinity membrane melatonin receptors MT1 and MT2 expression dynamics in lymphoid organs (i.e., spleen and thymus) of a seasonally breeding rodent Funambulus pennanti during two major reproductive phases (i...

This study investigated seasonal changes in the metabolic performance of spermatozoa and activity of the antioxidant enzymes in the seminal plasma of three wild boar/domestic pigs (aged 1.5 to 2.5 years) and the activity of the antioxidant enzymes in fluids of the cauda epididymidis and vesicular glands from 16 wild boar/domestic pig hybrids (aged 1 to 3 years). Parameters of the sperm metaboli...