Maternal Natal Environment and Breeding Territory Predict the Condition and Sex Ratio of Offspring

Females in a variety of taxa adjust offspring sex ratios to prevailing ecological conditions. However, little is known about whether conditions experienced during a female’s early ontogeny influence the sex ratio of her offspring. We tested for past and present ecological predictors of offspring sex ratios among known-age females that were produced as offspring and bred as adults in a population of house wrens. The body condition of offspring that a female produced and the proportion of her offspring that were male were negatively correlated with the size of the brood in which she herself was reared. The proportion of sons within broods was negatively correlated with maternal hatching date, and varied positively with the quality of a female’s current breeding territory as predicted. However, females producing relatively more sons than daughters were less likely to return to breed in the population the following year. Although correlative, our results suggest that the rearing environment can have enduring effects on later maternal investment and sex allocation. Moreover, the overproduction of sons relative to daughters may increase costs to a female’s residual reproductive value, constraining the extent to which sons might be produced in high-quality breeding conditions. Sex allocation in birds remains a contentious subject, largely because effects on offspring sex ratios are small. Our results suggest that offspring sex ratios are shaped by various processes and trade-offs that act throughout the female life history and ultimately reduce the extent of sex-ratio adjustment relative to classic theoretical predictions

A Review of RFID in Supply Chain Management: 2000–2015

This paper presents a systematic literature review of papers that were published in academic journals on the applications of radio frequency identification (RFID) in supply chain management between the years 2000 and 2015. As the literature on RFID is not confined to specific disciplines or repositories, this paper proposes a discipline-based framework for classifying RFID literature. Five main classification categories are used in this paper: technology, supply chain management, research methodology, application industries, and social aspects. The paper then focuses on the category of supply chain management and reviews 1187 articles that were published between 2000 and 2015 in rated journals. All the papers reviewed are further classified into eight subclasses under this category of supply chain management. The review yields useful insights into the anatomy of RFID literature in supply chain management, enhances evidence-based knowledge, and contributes to informing practice, policymaking and future research. The review reveals that even presently, despite technical and cost challenges, enormous potential exists for the application of RFID in several areas of supply chain management and the prospects are likely to grow into the future. Since RFID solutions have emerged primarily over only the past 20 years, significant research opportunities exist and would need to be addressed to continue to support the technology’s maturation, evaluation, adoption, implementation, and diffusion