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Based on phenotypes, two subspecies of Eurasian Magpies (Pica pica) are recognized in Norway, with nominate P. p. pica in southern Norway, and P. p. fennorum in northern Norway. In this study, we investigated whether there are genetically distinct groups of Magpies in Norway, which can be considered in the discussion of the subspecies status. We collected DNA from 61Magpies from seven locations in Norway, and measured genetic diversity using two types of markers: mitochondrial DNA sequences and microsatellites. Genetic differentiation among the Magpies was extremely low. Most of the variance was within populations, and the population identity and the putative subspecies border did not explain the genetic variance among the samples. Although microsatellite markers indicated genetic differentiation, the pattern was not consistent with the geographic locations of the sampling sites. Mismatch analysis suggested that the Magpie populations in Norway were formed by rapid expansion. Our results suggest that all the Magpies in Norway have originated from the same refugia after the last glaciation, their colonization in Norway happened quickly, and that the subspecies status of Magpies in Norway needs to be reconsidered. [ABSTRACT FROM AUTHOR]

We report the first case of non-parental infanticide in the Black-billed Magpie Pica pica. Using a video camera installed in the victims' nest, we recorded repeated visits (over 4 days) of an adult (each time one bird) who attacked six nestlings at each visit until they died or were evicted. The nest was one of 58 nests filmed over four breeding seasons. Collected evidence suggests that the perpetrator(s) might have been the female breeder of the neighbouring nest, possibly also her male partner. The parental female aggressively attacked the perpetrator. Post-infanticide expansion of breeding territory by the suspected perpetrator is the hypothetical ultimate explanation of the observed infanticide. Movie clips from inside the nest are shown at: , , , and . [ABSTRACT FROM AUTHOR]

In sexually size-dimorphic species, brood sex composition may exert differential effects on sex-specific mortality. We investigated the sex-specific mortality and body condition in relation to brood sex composition in nestlings of the black-billed magpie Pica pica. Neither significantly sex-biased production at hatching nor overall sex-biased mortality during the nestling period was found. Sex-specific mortality as a function of brood sex composition, however, differed between female and male nestlings. We found higher mortality for females in male-biased broods and higher mortality for males in female-biased broods, a phenomenon that we call ‘rarer-sex disadvantage’. As a result, fledging sex ratios became more biased in the direction of bias at hatching, a phenomenon that cannot be readily explained by previous hypotheses for sex-specific mortality. Two temporal variables, fledging date and laying date, were also correlated with sex-specific mortality: female nestlings in earlier broods experienced higher mortality than male nestlings whereas male nestlings in later broods experienced higher mortality. We suggest that this unusual pattern of mortality may be explained by adaptive adjustments of brood sex composition by parents, either through the effects of a slight sex difference in offspring dispersal patterns on parental fitness, or owing to sex differences as regards the benefits of early fledging. [ABSTRACT FROM AUTHOR]

Animal personality traits are defined as consistent individual differences in behavior over time and across contexts. Occasionally this inflexibility results in maladaptive behavioral responses to external stimuli. However, in social groups inflexible behavioral phenotypes might be favored as this could lead to more predictable social interactions. Two hypotheses seek to describe the optimal distribution of personality types within groups. The social niche specialization hypothesis states that individuals within groups should partition social roles, like personality types, to avoid conflict; whereas the conformity hypothesis states that individuals should assort with conspecifics of similar personality. However, no research so far has compared these hypotheses using data from wild animal systems. We tested boldness in the wild on 2 species with different social systems, the Mexican Jay and California Scrub-Jay. We found support for the conformity hypothesis over the social niche specialization hypothesis because individuals within groups of the social species had more similar personalities, and consequently there was a statistically significant group effect. The most likely mechanism for this conformity is social learning of behaviors through development, but more explicit research on this is needed. [ABSTRACT FROM AUTHOR]

Current theory for surface tension-dominant jumps on water, created for small-and medium-sized water strider species and used in bioinspired engineering, predicts that jumping individuals are able to match their downward leg movement speed to their size and morphology such that they maximize the takeoff speed and minimize the takeoff delay without breaking the water surface. Here, we use empirical observations and theoretical modeling to show that large species (heavier than ~80 mg) could theoretically perform the surface-dominated jumps according to the existing model, but they do not conform to its predictions, and switch to using surface-breaking jumps in order to achieve jumping performance sufficient for evading attacks from underwater predators. This illustrates how natural selection for avoiding predators may break the theoretical scaling relationship between prey size and its jumping performance within one physical mechanism, leading to an evolutionary shift to another mechanism that provides protection from attacking predators. Hence, the results are consistent with a general idea: Natural selection for the maintenance of adaptive function of a specific behavior performed within environmental physical constraints leads to size-specific shift to behaviors that use a new physical mechanism that secure the adaptive function. [ABSTRACT FROM AUTHOR]

Microhabitat segregation among grasshopper species in Asia has not been well studied. We determined the differences in the use of substrates by three common North East Asian grasshopper species co-existing on a natural meadow near Seoul, South Korea. While many Oedaleus infernalis individuals were found on the ground, Acrida cinerea and Atractomorpha lata were usually observed on plants. Acrida cinerea was mostly observed on the grass Zoysia japonica (Poaceae) and Atractomorpha lata was mostly found on plants from the family Asteraceae. This is the first study to provide quantitative information about microhabitat differences among some common grasshoppers in rural habitats of continental North East Asia. Future studies should focus on determining the mechanisms that produce such ecological segregation. [ABSTRACT FROM AUTHOR]

In recent research, personality consistency has become an important characteristic. Diverse traits and human-animal interactions, in particular, are studied in the field of personality consistency in dogs. Here, we investigated the consistency of dominant behaviours in cloned and control groups followed by the modified Puppy Aptitude Test, which consists of ten subtests to ascertain the influence of genetic identity. In this test, puppies are exposed to stranger, restraint, prey-like object, noise, startling object, etc. Six cloned and four control puppies participated and the consistency of responses at ages 7-10 and 16 weeks in the two groups was compared. The two groups showed different consistencies in the subtests. While the average scores of the cloned group were consistent (P = 0.7991), those of the control group were not (P = 0.0089). Scores of Pack Drive and Fight or Flight Drive were consistent in the cloned group, however, those of the control group were not. Scores of Prey Drive were not consistent in either the cloned or the control group. Therefore, it is suggested that consistency of dominant behaviour is affected by genetic identity and some behaviours can be influenced more than others. Our results suggest that cloned dogs could show more consistent traits than non-cloned. This study implies that personality consistency could be one of the ways to analyse traits of puppies. [ABSTRACT FROM AUTHOR]

Many species have evolved a suite of anti-predator defences, rather than a single defence. These multiple defences may operate in synchrony or separately at different stages of predation sequence to protect the prey. However, empirical documentation on how multiple defences, as a whole, combine to protect prey, as well as quantitative evaluations of how and when they are deployed, are scarce. In the present study, we investigated the univoltine spotted lanternfly, Lycorma delicatula, which has cryptic forewings, defensive chemicals, and multiple behavioural defences, including rapid jumping away, sudden display of its conspicuous hindwings and abdomen (a startle/ deimatic display), and death feigning. The aims of the present study were to: (1) characterize the modality of sensory stimuli that trigger the behavioural defences; (2) identify the stage(s) of the predation sequence in which L. delicatula employs each behavioural defence; and (3) investigate a range of intrinsic/extrinsic factors that might affect the execution of anti-predator responses. First, a preliminary test that simulated a range of sensory stimuli on L. delicatula suggested that they rarely responded to nontactile stimuli. This suggests that the species relies on crypsis as a primary defence unless it is physically contacted. Next, we simulated predatory attacks on the species at two different times of year (early and late season as adults). When physically contacted, the primary response of individuals was jumping away. However, when jumping was initially hindered (by grabbing), they then tended to employ deimatic display. Intriguingly, we found clear seasonal differences in these post-attack defences: after performing deimatic display, individuals were more likely to jump away in the early season, whereas death feigning was more frequent in the late season. We present adaptive explanations for this seasonal switch in anti-predator responses. [ABSTRACT FROM AUTHOR]

Jumping on water is a unique locomotion mode found in semi-aquatic arthropods, such as water striders. To reproduce this feat in a surface tension-dominant jumping robot, we elucidated the hydrodynamics involved and applied them to develop a bio-inspired impulsive mechanism that maximizes momentum transfer to water. We found that water striders rotate the curved tips of their legs inward at a relatively low descending velocity with a force just below that required to break the water surface (144 millinewtons/meter). We built a 68-milligram at-scale jumping robotic insect and verified that it jumps on water with maximum momentum transfer. The results suggest an understanding of the hydrodynamic phenomena used by semi-aquatic arthropods during water jumping and prescribe a method for reproducing these capabilities in artificial systems. [ABSTRACT FROM AUTHOR]

Camoulage can be attained via mechanisms such as background matching (resembling the general background) and disruptive coloration (hindering the detection of an animal's outline). However, despite much conceptual work with artificial stimuli there have to date been few studies of how such camoulage types work in real animals in their natural environments. Here, using avian vision models and image analysis, we tested which concealing mechanisms operate to provide camoulage during behavioral choice of a resting position in 2 bark-resting moths, Hypomecis roboraria and Jankowskia fuscaria. Our results suggest that both species reinforced their crypticity in terms of both background matching and disruptive coloration. However, the detailed mechanisms (such as achromatic/ chromatic matching or pattern direction matching) that each species exploits differed between the 2 species. Our results demonstrate that an appropriate behavioral choice of background and body orientation is important to improve camoulage against natural predators, and highlight the mechanisms that confer camoulage to cryptic animals in their natural habitats. [ABSTRACT FROM AUTHOR]