Does predation control adult sex ratios and longevities in marine pelagic copepods?

We assess the causes of adult sex ratio skew in marine pelagic copepods by examining changes in these ratios between the juveniles and adults, sexual differences in juvenile stage durations, and mortality rates of adults in the field and laboratory (when free from predators). In the field, late copepodite stages (CIV and CV) commonly have sex ratios that are either not significantly different from equity (1 : 1), or slightly male biased. By contrast, in adults, these ratios are commonly significantly biased toward female dominance. Sex ratio skews are therefore primarily attributable to processes in adults. Members of the non-Diaptomoidea have especially skewed adult ratios; in the members Oithonidae and Clausocalanidae this is not generated from differences between male and female adult physiological longevity (i.e., laboratory longevity when free of predators). In the genera Acartia, Oithona, and Pseudocalanus, we estimate that predation mortality contributed ≥ 69% of the field mortality rate in adult males, whereas in Acartia, Oithona, and Calanus adult females, this is ≥ 36%.We conclude that (1) adult sex ratio skew in pelagic copepods is primarily due to differential mortality of the sexes in the adult stage and not in juveniles, (2) mortality rates of adult Acartia, Pseudocalanus, and Oithona are dominated by predation mortality rather than physiological longevity (except under extreme food limitation), and (3) in Pseudocalanus and Oithona, elevated mortality rates in adult males to females is predominantly due to higher predation on males. Our work demonstrates that we now need to develop a more comprehensive understanding of the importance of feeding preferences in predators. Continue reading full article

Effect of supplementation silage ("Festuca dolichophylla, Avena sativa and Vicia sativa") on weight gain and mortality in adult alpacas ("Vicugna pacos")

This study was conducted in order to evaluate the effect of supplementation with silage (Festuca dolichophylla, Avena sativa and Vicia sativa) on weight gain and mortality in adult alpacas, during the months of dry season (June to August) in Huancavelica region. 300 female alpacas 3 and 4 years of age (physiological state: pregnant) were used, which were assigned to the following treatments: SP, grazing only PSE15, grazing plus supplementation of 1.5 kg of silage. Alpacas were supplemented once daily. In each alpaca they were recorded live weight at the beginning and end of the experiment. The weight gain was -0.02 y 2.05 kg for SP and PSE15 respectively (p <0.001) treatments. Mortality was 5.3% and 2.7% for SP and PSE15 respectively (p=0.073) treatments. It can be concluded under the conditions of this trial silage supplementation has effect on weight gain and maybe also on mortality in alpacas.

Digital Literacy in Story Spaces

This paper describes a study of digital literacy where the researcher worked with one group of English language arts teacher candidates and one of adolescents, reading and writing hypertext fiction. The findings suggest that the adolescent readers/writers brought a more flexible and multiliterate approach to their digital literacy processes than the teacher candidates.

The librarian is in: a consultation model for information literacy formative assessment

Formative assessment was introduced in Rehabilitation Therapy students’ information literacy programs in Fall Term 2006 in the course OT/PT 892: Evidence-Based Practice. It was subsequently employed in the Winter Term 2008 and again in the Spring Term 2008. Formative assessment during student/librarian face-to-face consultations was one of a variety of teaching techniques used in the program. Other techniques included: a required reading; an interactive hands-on searching session; and a summative assessment of the final revised search strategy assignment (these techniques varied somewhat over the 3 classes). With the 2008 entrance class, this course content moved to OT/PT 898: Critical Enquiry, largely in Module 3: Reviewing the Literature. One of the Critical Enquiry’s learning objectives is: “recognize and reflect on the complexity of gathering evidence to inform decision-making.”