Lack of functional link in the tadpole morphology induced by predators

Most studies of predator-induced plasticity have focused on documenting how prey species re- spond to predators by modifying phenotypic traits and how traits correlate with fitness. We have previously shown that Pleurodema thaul tadpoles exposed to the dragonfly Rhionaeschna varie- gata responded strongly by showing morphological changes, less activity, and better survival than non-exposed tadpoles. Here, we tested whether there is a functional link between morphological plasticity and increased survival in the presence of predators. Tadpoles that experienced predation risk were smaller, less developed, and much less active than tadpoles without this experience. Burst speed did not correlate significantly with morphological changes and predator-induced deeper tails did not act as a lure to divert predator strikes away from the head. Although we have previously found that tadpoles with predator-induced morphology survive better under a direct predator threat, our results on the functional link between morphology and fitness are not conclu- sive. Our results suggest that in P. thaultadpoles （1） burst speed is not important to evade preda- tors, （2） those exposed to predators reduce their activity, and （3） morphological changes do not divert predator attacks away from areas that compromise tadpole survivalEE. Our results show that morphological changes in P. thaul tadpoles do not explain burst speed or lure attraction, al- though there was a clear reduction of activity, which itself reduces predation. We propose that changes in tadpole activity could be further analyzed from another perspective, with morphological change as an indirect product of behavior mediated by physiological mechanisms.

Effect of metal surface morphology on nano-structured patterns induced by a femtosecond laser pulse and its experimental verification

The effect of material surface morphology on the periodic subwavelength of nano-structures induced by a femtosecond（fs） laser was investigated systematically from the initial surface roughness, the different scratches, the pre-formed ripples, and the ＂layer-carving＂ technology experiments. The results of the comparative experiments indicate that the initial surface conditions of the target surface have no obvious effects on the spatial structured periods（SSPs） and the ripple orientation of the periodic nano-structures induced by a fs laser, which agreed well with the foretold present surface two-plasmon resonance（STPR） model. Furthermore, different shapes of nanogrids with high regularity and uniformity were obtained by fs-laser fabrication.

DEGENERATIVE MECHANISM OF ARTICULAR CARTILAGE INDUCED BY LOW STRESS A MORPHOLOGICAL STUDY

Immobilization leads not only to diminished joint movement but also low stress of articular cartilage. The present investigation was undertaken to observe the morphological changes which arose in articular cartilage with low stress. The joint motion remained intact. Articular cartilage from the left knees of 66 rats whose left calcaneal tendons had been transected was examined under transmission electron microscope and light microscope. The degenerative changes were observed: decreased functional activity of chondrocytes progressively degenerated cartilage and lack of compensatory proliferation of chondrocytes at the early stage. We propose that the degeneration of articular cartilage induced by immobilization is the result of combination of low stress and lack of joint motion. The following degenerative mechanism begins with chondrocytes. Chondrocyte and matrix influence each other in a vicious cycle. Low stress may restrain the repair activities.