Leg loss decreases endurance and increases oxygen consumption during locomotion in harvestmen.

Animal movements are highly constrained by morphology and energetics. In addition, predictable bodily damage can constrain locomotion even further. For example, for animals moving on land, losing legs may impose additional costs. We tested if losing legs affects the distance travelled over time (endurance) and the metabolic costs of locomotion (oxygen consumption) in Nelima paessleri harvestmen. These arachnids voluntary releases legs (i.e., autotomy) in response to predation attempts. We used flow-through respirometry as animals moved on a treadmill inside a sealed chamber. We found that endurance decreased gradually with an increasing number of legs lost. Interestingly, oxygen consumption increased only for harvestmen that lost three legs, but not for individuals that lost only a single leg. These results have different ecological and evolutionary implications. Reduced endurance may impair an animal's ability to continue moving away from potential predators, while increased oxygen consumption makes movement costlier. Our findings suggest that individuals have a threshold number of legs that can be lost before experiencing measurable energetic consequences. Overall, our findings illustrate how animals respond to morphological modifications (i.e., damage) that affect the physiology of locomotion.

The narrative matrix and wordless narrations: a research note.

Preverbal and non-speaking children are able to share an experience, recount an event, and tell a story in collaboration with an intimate adult who provides the words. These children's narrative expressions take the form of gestures, sounds not recognizable as standard language, the combination of sounds and gestures, and sequenced actions. These narrative forms are understood by the parent or intimate adult because child and adult dwell within a shared narrative matrix, defined by personal, social, temporal, and spatial aspects of life together. In this article, narrative inquiry is presented as a research methodology that may be of interest to the augmentative and alternative communication (AAC) community. In addition, examples are presented.

Letters.

WHO HAS UPDATE ON RESEARCH EDUCATING DOCTORS A NATIONAL RESOURCE? A HOLISTIC APPROACH MORE SAMPLES NEEDED A USEFUL RESOURCE THE APPLIANCE OF SCIENCE WILL THE PRICE BE RIGHT? COMMUNITY NEEDS DISPARITY IN CARE BACK TO BASICS INFECTION MATTERS PREACHING TO THE CONVERTED? SUPPORT FOR STAFF A NURSE-LED DISCIPLINE INNOVATION NEEDED PRESCRIBING IMPLICATIONS.