Sexual reproduction is essential for the life cycle of most angiosperms. However, pseudovivipary is an important reproductive strategy in some grasses. In this mode of reproduction, asexual propagules are produced in place of sexual reproductive structures. However, the molecular mechanism of pseudovivipary still remains a mystery. In this work, we found three naturally occurring mutants in ric...

Populations of Allium vineale commonly include individuals with very different allocation patterns to three modes of reproduction: sexual flowers, aerially produced asexual bulbils, and belowground asexual offsets. If selection is currently acting to maintain these different allocation patterns there must be a genetic basis for variation in allocation to these three reproductive modes. In addit...

Ocean climate affects the life history and demography of top marine predators through changes in local prey availability. In the California Current System, abundance and distribution of mid trophic-level forage fish may be affected by seasonal and interannual variability in upwelling. We tested the hypothesis that upwelling influences forage fish availability and response of a seabird, but that...

Reniform nematode (Rotylenchulus reniformis) is a major pest of cotton in the southeastern United States. The objective of this study was to examine the variation of reniform nematode populations from cotton-growing locations in the United States where it is prevalent. Multivariate analysis of variance and discriminant analysis were used to determine the variability of morphology in males and i...

We report results of an acoustic duration reproduction task with stimulus duration of 2, 4, and 6 s, using 45 emotionally negative, positive, and neutral sounds from the International Affective Digitized Sounds System, in a sample of 31 young healthy participants. To investigate the influence of induced emotions on perceived duration, the effects of emotional modulation were quantified in two w...

Long-lived iteroparous species often show aging-related changes in reproduction that may be explained by 2 non-mutually exclusive hypotheses. The terminal investment hypothesis predicts increased female reproductive effort toward the end of the life span, as individuals have little to gain by reserving effort for the future. The senescence hypothesis predicts decreased female reproductive outpu...

In birds, larger females generally have greater breeding propensity, reproductive investment, and success than do smaller females. However, optimal female body size also depends on how natural selection acts during other parts of the life cycle. Larger female Lesser Scaup (Aythya affinis) produce larger eggs than do smaller females, and ducklings from larger eggs survive better than those hatch...

OBJECTIVE To examine the outcome of assisted reproduction techniques (ART) using cryopreserved semen from patients with cancer. DESIGN Prospective. SETTING Therapeutic semen banking program at a tertiary healthcare center. PATIENT(S) Twenty-nine men with cancer who cryopreserved their sperm before treatment at our facility from 1982 to 2001 and withdrew their samples for assisted reproduc...

Studies of life histories often compare species to discern patterns in the evolution of traits. Major components of life histories appear to involve important aspects of species biology, and the first such component appears to be body size. We tested whether the second major component of variation in life histories of mammals is a continuum from species with short lives to long lives, the “fast...