Abstract In many bird species, physical aggression between males become more frequent during the female’s fertile period, as female encounters with extra-pair are and can entail paternity losses. Male aggressiveness this stage has been proposed crucial for ensuring male reproductive success. Thus, plumage ornaments could represent honest signals of individual quality that reflect paired territo...

We analyzed individual variation in work load (nest visit rate) during chick-rearing, and the consequences of this variation in terms of breeding productivity, in a highly synchronous breeder, the European starling (Sturnus vulgaris) focusing on female birds. There was marked (10- to 16-fold) variation in total, female and male nest visit rates, among individuals, but individual variation in fe...

Determining the mechanisms that mediate investment decisions between current and future reproductive attempts is still a key goal of life-history studies. Since baseline levels of stress hormones (glucocorticoids - GCs) act as predictive and labile regulators of daily energetic balance in vertebrates they remain excellent candidates for mediating investment decisions both within and across repr...

BACKGROUND Polyandry is widespread throughout the animal kingdom. In the absence of direct benefits of mating with different males, the underlying basis for polyandry is enigmatic because it can carry considerable costs such as elevated exposure to sexual diseases, physical injury or other direct fitness costs. Such costs may be balanced by indirect genetic benefits to the offspring of polyandr...

Background: We used the Caribbean spiny lobster Panulirus argus, one of the largest brooding invertebrates in the Western Atlantic, to test for the presence/absence of active parental care and to explore reproductive performance in large brooding marine organisms. Given [i] the compact and large embryo masses produced by P. argus, [ii] the expected disproportional increase in brooding costs wit...

Parents are selected to maximize their fitness by allocating care among their progeny in relation to the differential reproductive value of offspring. Nestlings have been hypothesized to signal need for parental care reliably through their begging behavior, but offspring condition as reflected by their reproductive value may likewise affect begging and hence provisioning. We assessed the relati...

In the early 2000s, a new component of the cost of reproduction was proposed: oxidative stress. Since then the oxidative cost of reproduction hypothesis has, however, received mixed support. Different arguments have been provided to explain this. Among them, the lack of a life-history perspective on most experimental tests was suggested. We manipulated the levels of a key intracellular antioxid...

Total Hemocyte Count (T.H.C.) of 5 instar larvae of Muga Silkworm Antheraea assama Ww reared at four different sericulture farms situated at different altitudes, viz, Khanapara State Sericulture Farm, Assam, altitude 55.5m above sea level (ASL); Nongpoh (Central Silk Board farm), Meghalaya, altitude 464m ASL; Tura (Central Silk Board farm), West Garo Hills, Meghalaya, 657m ASL; and Kalimpong (C...

Largemouth bass Micropterus salmoides broods were experimentally reduced in size to test whether brood size (BS) and simulated brood depredation affect the decision by a male to continue providing care for its brood or to abandon that brood prematurely before its offspring reach independence. The highest ranked of the generalized linear models predicting brood abandonment was based on the numbe...