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Amniote vertebrates share a suite of extra-embryonic membranes that distinguish them from anamniotes. Other than that, however, their reproductive characteristics could not be more different. They differ in basic ectothermic vs endothermic physiology, in that two clades evolved powered flight, and one clade evolved a protective shell. In terms of reproductive strategies, some produce eggs and others give birth to live young, at various degrees of development. Crucially, endotherms provide lengthy parental care, including thermal and food provisioning—whereas ectotherms seldom do. These differences could be expected to manifest themselves in major differences between clades in quantitative reproductive traits. We review the reproductive characteristics, and the distributions of brood sizes, breeding frequencies, offspring sizes and their derivatives (yearly fecundity and biomass production rates) of the four major amniote clades (mammals, birds, turtles and squamates), and several major subclades (birds: Palaeognathae, Galloanserae, Neoaves; mammals: Metatheria and Eutheria). While there are differences between these clades in some of these traits, they generally show similar ranges, distribution shapes and central tendencies across birds, placental mammals and squamates. Marsupials and turtles, however, differ in having smaller offspring, a strategy which subsequently influences other traits.

The confusion effect - the decreased attack-to-kill ratio of a predator with increase in prey group size - is thought to be one of the main reasons for the evolution of group living in animals. Despite much interest, the influence of prey coloration on the confusion effect is not well understood. We hypothesized that dynamic colour change in motion (due to interference coloration or flash marks), seen widely in many group living animals, enhances the confusion effect. Utilizing a virtual tracking task with humans, we found targets that dynamically changed colour during motion were more difficult to track than targets with background matching patterns, and this effect was stronger at larger group sizes. The current study thus provides the first empirical evidence for the idea that dynamic colour change can benefit animals in a group and may explain the widespread occurrence of dynamic colorations in group-living animals.

Understanding the functions of animal coloration has been a long-standing question in evolutionary biology. For example, the widespread occurrence of striking longitudinal stripes and colourful tails in lizards begs for an explanation. Experiments have suggested that colourful tails can deflect attacks towards the tail (the 'deflection' hypothesis), which is sacrificable in most lizards, thereby increasing the chance of escape. Studies also suggest that in moving lizards, longitudinal body stripes can redirect predators' strikes towards the tail through the 'motion dazzle' effect. Despite these experimental studies, the ecological factors associated with the evolution of such striking colorations remain unexplored. Here, we investigated whether predictions from motion dazzle and attack deflection could explain the widespread occurrence of these striking marks using comparative methods and information on eco-physiological variables (caudal autotomy, diel activity, microhabitat and body temperature) potentially linked to their functioning. We found both longitudinal stripes and colourful tails are associated with diurnal activity and with the ability to lose the tail. Compared to stripeless species, striped species are more likely to be ground-dwelling and have higher body temperature, emphasizing the connection of stripes to mobility and rapid escape strategy. Colourful tails and stripes have evolved multiple times in a correlated fashion, suggesting that their functions may be linked. Overall, our results together with previous experimental studies support the notion that stripes and colourful tails in lizards may have protective functions based on deflective and motion dazzle effects.

Many lizards have contrasting longitudinal body stripes, thought to dazzle predators during motion, thereby misdirecting attacks to the expendable tail. To understand what promotes evolution of such “dazzle” patterns, we performed a touchscreen predation experiment with humans and found stripes to be more effective in smaller prey. Comparisons across lizard species showed that stripes are correlated to smaller body length. We conclude that body length has a strong effect on the functioning of dazzle colorations.

Motion dazzle markings comprise patterns such as stripes and zig-zags that are postulated to protect moving prey by making predators misjudge the prey’s speed or trajectory. Recent experiments have provided conflicting results on their effect on speed perception and attack success. We focus on motion dazzle stripes and investigate the influence of four parameters—stripe orientation, stripe contrast, target size, and target speed—on perceived speed and attack success using a common experimental paradigm involving human “predators” attacking virtual moving targets on a computer touchscreen. We found that high-contrast stripes running parallel or perpendicular to the direction of motion reduce attack success compared to conspicuous uniform targets. Surprisingly, parallel stripes induced underestimation of speed, while perpendicular stripes induced overestimation of speed in relation to uniform black, suggesting that misjudgment of speed per se is sufficient to reduce attack accuracy. Across all the experiments, we found some support for parallel stripes inducing underestimation of target speed but these stripes reduced attack success only when targets were small, moved at an intermediate speed, and had high internal contrast. We suggest that prey features (e.g., size or speed) are an important determinant of capture success and that distortion of speed perception by a color pattern does not necessarily translate to reduced capture success of the prey. Overall, our results support the idea that striped patterns in prey animals can reduce capture in motion but are effective under a limited set of conditions.

The development of methods to estimate rates of speciation and extinction from time- calibrated phylogenies has revolutionized evolutionary biology by allowing researchers to correlate diversification rate shifts with causal ecological factors. A growing number of researchers are interested in testing whether the evolution of a trait or a trait variant has influenced speciation rates, and three modelling methods – BiSSE, MEDUSA and BAMM – have been widely used in such studies. We simulated phylogenies with a single speciation rate shift each, and evaluated the power of the three methods to detect these shifts. We varied the degree of increase in speciation rate (rate asymmetry), the number of tips, the tip-ratio bias (ratio of number of tips with each character state) and the relative age in relation to overall tree age when the rate shift occurred. All methods had good power to detect rate shifts when the rate asymmetry was strong and the sizes of the two lineages with the distinct speciation rates were large. Even when lineage size was small, power was good when rate asymmetry was high. In our simulated scenarios, small lineage sizes appear to affect BAMM most strongly. Tip-ratio influenced the accuracy of speciation rate estimation but did not have a strong effect on power to detect rate shifts. Based on our results, we provide some suggestions to users of these methods.

Amyloid beta peptide accumulation in the brain poses a serious threat during Alzheimer’s disease. Various strategies to remove or disrupt these plaques with nanoparticles is an emerging area for the treatment for neurodegenerative diseases. The present work attempts to develop a novel strategy to remove the plaques using magnetic field by employing magnetic nanoparticles conjugated with a plaque-targeting ligand. Thioflavin-S (TF-S) was covalently linked to magnetic iron oxide incorporated mesoporous silica, SBA-15 and the material was characterized using microscopic and spectroscopic techniques. This magnetic conjugate (IO-SBA-TF-S) was found to display the ability to remove in vitro, KLVFF peptide, a recognition motif in β-amyloid that has been implicated in plaque formation. This system represents a potential smart system that could herald in the next generation therapeutic strategy for Alzheimer’s disease and related disorders.

Conspicuous coloration, which presumably makes prey more visible to predators, has intrigued researchers for long. Contrastingly coloured, conspicuous striped patterns are common among lizards and other animals, but their function is not well known. We propose and test a novel hypothesis, the ‘redirection hypothesis’, wherein longitudinal striped patterns, such as those found on the anterior body parts of most lacertilians, redirect attacks away from themselves during motion towards less vulnerable posterior parts, for example, the autotomous tail. In experiments employing human ‘predators’ attacking virtual prey on a touchscreen, we show that longitudinal striped patterns on the anterior half of prey decreased attacks to the anterior and increased attacks to the posterior. The position of stripes mattered—they worked best when they were at the anterior. By employing an adaptive psychophysical procedure, we show that prey with striped patterning are perceived to move slower, offering a mechanistic explanation for the redirective effect. In summary, our results suggest that the presence of stripes on the body (i.e. head and trunk) of lizards in combination with caudal autotomy can work as an effective anti-predator strategy during motion.

Does convergent evolution always result from different lineages experiencing similar evolutionary dynamics? Hagey et al (2017) report the dynamics of adhesive performance evolution to be distinct in two lizard clades (anoles and geckos) despite independent convergence in adhesive toe pad structures, suggesting convergence can occur with dissimilar macroevolutionary dynamics. This article is protected by copyright. All rights reserved