Predation is considered one of the main costs to reproduction but is rarely examined from a physiological perspective. In particular, little is known about the influence of brood predation pressure on the physiology of parents engaged in care. Brood defense, even when there is no direct threat to the parent, can be costly as it requires constant vigilance and chasing predators to protect the de...

White shrimp Litopenaeus vannamei immersed in seawater (35‰) containing Gracilaria tenuistipitata extract (GTE) at 0 (control), 400, and 600 mg/L for 3 h were exposed to 5 mg/L ammonia-N (ammonia as nitrogen), and immune parameters including hyaline cells (HCs), granular cells (GCs, including semi-granular cells), total hemocyte count (THC), phenoloxidase (PO) activity, respiratory bursts (RBs)...

Infectious disease constitutes a major obstacle to the sustainability of shrimp aquaculture worldwide and a significant threat to natural populations of shrimp and other crustacea. The study of the shrimp immune system, including the response to viral infection, has been hampered by a relative lack of molecular genetic information and of tools suitable for high-throughput assessment of gene exp...

Social Hymenoptera have become key organisms for tests of sex-ratio theory. We assess the role of resources for explaining sex-ratio variation in a highly male-biased population of the ant Formica exsecta. Key predictions of two of the three leading hypotheses invoking an effect of resource availability on sex ratios in social insects are not upheld. One prediction of the multifaceted parental-...

in teleosts the insulin-like growth factor-i, a member of igf system, play an important role in the control of growth and reproduction including metabolism, cell division, oogenesis, final oocyte maturation and secretory activity. this system is controlled by several hormones and metabolic status. serum igf-i, thyroxine (t4) and cortisol levels were studied in two female brood stocks (caught fr...

Barn swallows Hirundo rustica have white spots on their tail feathers, and they have been hypothesized to be a handicap because white spots are prone to feather breakage, ectoparasites are disproportionately common in white spots, and size of white spots increases with tail length. Here I test for attractiveness of narrow and long tail spots by manipulation of their shape while using complete p...

Melanosis is a major problem associated with the quality loss of Pacific white shrimp. This is mediated by polyphenoloxidase (PPO), in which biochemical and molecular properties can be varied with species, molting period, etc. The better understanding of PPO characteristics should pave a way for lowering melanosis, thereby extending the shelf life of Pacific white shrimp during handling and sto...