Showing papers by "Sanjay P. Sane published in 2016"

Airflow and optic flow mediate antennal positioning in flying honeybees

Abstract: To maintain their speeds during navigation, insects rely on feedback from their visual and mechanosensory modalities. Although optic flow plays an essential role in speed determination, it is less reliable under conditions of low light or sparse landmarks. Under such conditions, insects rely on feedback from antennal mechanosensors but it is not clear how these inputs combine to elicit flight-related antennal behaviours. We here show that antennal movements of the honeybee, Apis mellifera, are governed by combined visual and antennal mechanosensory inputs. Frontal airflow, as experienced during forward flight, causes antennae to actively move forward as a sigmoidal function of absolute airspeed values. However, corresponding front-to-back optic flow causes antennae to move backward, as a linear function of relative optic flow, opposite the airspeed response. When combined, these inputs maintain antennal position in a state of dynamic equilibrium.

Orientation in high-flying migrant insects in relation to flows: mechanisms and strategies

Abstract: High-flying insect migrants have been shown to display sophisticated flight orientations that can, for example, maximize distance travelled by exploiting tailwinds, and reduce drift from seasonally optimal directions. Here, we provide a comprehensive overview of the theoretical and empirical evidence for the mechanisms underlying the selection and maintenance of the observed flight headings, and the detection of wind direction and speed, for insects flying hundreds of metres above the ground. Different mechanisms may be used—visual perception of the apparent ground movement or mechanosensory cues maintained by intrinsic features of the wind—depending on circumstances (e.g. day or night migrations). In addition to putative turbulence-induced velocity, acceleration and temperature cues, we present a new mathematical analysis which shows that ‘jerks’ (the time-derivative of accelerations) can provide indicators of wind direction at altitude. The adaptive benefits of the different orientation strategies are briefly discussed, and we place these new findings for insects within a wider context by comparisons with the latest research on other flying and swimming organisms. This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight’.

Bioinspiration and Biomimicry: What Can Engineers Learn from Biologists?

Abstract: The field of biomechanics thrives on collaborations between engineers and biologists. With the recent emphasis on biomimicry and bioinspiration, such collaborations are bound to increase in number and may be central to many future research programs. Far too often, however, there is no resonance between the philosophies that guide each research program. Engineers tend to look at biological phenomena with a designer’s eye, something against which biologists are explicitly cautioned. On the other hand, biologists may often prefer a descriptive route over a mechanistic one. How can we make such collaborations resonate better from an intellectual perspective? In this essay, I describe a short historical account of biomimicry and bioinspiration, and offer suggestions for better collaborations between engineers and biologists, with examples of cases in which fruitful approaches have been adopted.