Stimulus-dependent orientation strategies in monarch butterflies

Insects are well-known for their ability to keep track of their heading direction based on a combination of skylight cues and visual landmarks. This allows them to navigate back to their nest, disperse throughout unfamiliar environments, as well as migrate over large distances between their breeding and non-breeding habitats. The monarch butterfly (Danaus plexippus) for instance is known for its annual southward migration from North America to certain trees in Central Mexico. To maintain a constant flight route, these butterflies use a time-compensated sun compass for orientation which is processed in a region in the brain, termed the central complex. However, to successfully complete their journey, the butterflies' brain must generate a multitude of orientation strategies, allowing them to dynamically switch from sun-compass orientation to a tactic behavior toward a certain target. To study if monarch butterflies exhibit different orientation modes and if they can switch between them, we observed the orientation behavior of tethered flying butterflies in a flight simulator while presenting different visual cues to them. We found that the butterflies' behavior depended on the presented visual stimulus. Thus, while a dark stripe was used for flight stabilization, a bright stripe was fixated by the butterflies in their frontal visual field. If we replaced a bright stripe by a simulated sun stimulus, the butterflies switched their orientation behavior and exhibited compass orientation. Taken together, our data show that monarch butterflies rely on and switch between different orientation modes, allowing them to adjust orientation to the actual behavioral demands of the animal.

Employee’s Market Orientation Behavior and Firm’s Internal Marketing Mechanism: A Multilevel Perspective of Job Performance Theory

The competition in today’s market is increasingly intensive. Employees’ market orientation behavior (MOB) is crucial for a firm to respond to market changes and attain its business performance goal. Moreover, a firm must exercise the internal marketing mechanism (IMM) to prepare employees for providing superior service to satisfy internal and external customers’ needs. This study aims to examine how the IMM works with knowledge integration (KI), relationship quality (RQ), relational bond (RB), and organizational citizenship behavior (OCB) to influence MOB. A total of 471 valid responses from employees of 47 banks were collected. The Hierarchical Linear Model is used to analyze the IMM’s effects (as the organizational-level variable) on MOB (as the outcome variables) and the relationships between the other variables (as the individual-level variables) and MOB. The results show that all predictor variables have significant and direct effects on MOB. The IMM’s moderating effects are significant when it interacts with OCB and RB, but not RQ. The negative interaction effect of IMM and OCB offers a caveat to corporate management in balancing OCB activities among the employees.

Application of the Folgar–Tucker model to predict the orientation of particles of different aspect ratios in polymer suspensions

The increasing requirements on plastic parts demand a rising use of combined functional and reinforcing materials. Therefore, often reinforcing particles with different aspect ratios are added to the plastic as additive mixtures. However, the engineering design process of reinforced parts requires an early knowledge of the expected orientation of the reinforcing particles. Numerous models try to predict the orientation of particles in polymer suspensions. However, the interaction coefficient strongly depends on the aspect ratio of the particles and a prediction of the orientation behavior of additive mixtures with differently shaped particles has not been validated using conventional methods. In this work, the orientation of differently shaped particle mixtures in polymer suspensions is investigated for different fluid channel geometries. Finally, the Folgar–Tucker model is applied to filler mixtures and implemented into OpenFOAM®, which enables the comparison of filler orientation in different fluid channel geometries. Regarding the experiments a characteristic increase of the interaction coefficient was observed at a filling level of 5%. Furthermore, it was shown that a balanced mixing ratio yields higher interaction coefficients. With regard to the performed simulations, it was possible to show qualitatively how a considered interaction between fibers and platelets affects the orientations.

An integrative investigation of sensory organ development and orientation behavior throughout the larval phase of a coral reef fish

The dispersal of marine larvae determines the level of connectivity among populations, influences population dynamics, and affects evolutionary processes. Patterns of dispersal are influenced by both ocean currents and larval behavior, yet the role of behavior remains poorly understood. Here we report the first integrated study of the ontogeny of multiple sensory systems and orientation behavior throughout the larval phase of a coral reef fish—the neon goby, Elacatinus lori. We document the developmental morphology of all major sensory organs (lateral line, visual, auditory, olfactory, gustatory) together with the development of larval swimming and orientation behaviors observed in a circular arena set adrift at sea. We show that all sensory organs are present at hatch and increase in size (or number) and complexity throughout the larval phase. Further, we demonstrate that most larvae can orient as early as 2 days post-hatch, and they swim faster and straighter as they develop. We conclude that sensory organs and swimming abilities are sufficiently developed to allow E. lori larvae to orient soon after hatch, suggesting that early orientation behavior may be common among coral reef fishes. Finally, we provide a framework for testing alternative hypotheses for the orientation strategies used by fish larvae, laying a foundation for a deeper understanding of the role of behavior in shaping dispersal patterns in the sea.

Spatial, but not temporal, aspects of orientation are controlled by the fine scale distribution of chemical cues in turbulent odor plumes

Orientation within turbulent odor plumes occurs across a vast range of spatial and temporal scales. From salmon homing across featureless oceans to microbes forming reproductive spores, the extraction of spatial and temporal information from chemical cues is a common sensory phenomenon. Yet, given the difficulty of quantifying chemical cues at the spatial and temporal scales used by organisms, discovering what aspects of chemical cues controls orientation behavior has remain elusive. In this study, we place electrochemical sensors on the carapace of orienting crayfish and measure, with fast temporal rates and small spatial scales, the concentration fluctuations arriving at the olfactory appendages during orientation. The results of these studies show that the spatial aspects of orientation (turning and heading angles) are controlled by the temporal aspects of odor cues.