Smelling on the fly: sensory cues and strategies for olfactory navigation in Drosophila

Abstract

Navigating toward (or away from) a remote odor source is a challenging problem that requires integrating olfactory information with visual and mechanosensory cues. Drosophila melanogaster is a useful organism for studying the neural mechanisms of these navigation behaviors. There is a wealth of genetic tools in this organism, as well as a history of inventive behavioral experiments. There is also a large and growing literature in Drosophila on the neural coding of olfactory, visual, and mechanosensory stimuli. Here we review recent progress in understanding how these stimulus modalities are encoded in the Drosophila nervous system. We also discuss what strategies a fly might use to navigate in a natural olfactory landscape while making use of all these sources of sensory information. We emphasize that Drosophila are likely to switch between multiple strategies for olfactory navigation, depending on the availability of various sensory cues. Finally, we highlight future research directions that will be important in understanding the neural circuits that underlie these behaviors.

Natural search algorithms as a bridge between organisms, evolution, and ecology

“…are too small to directly perceive concentration gradients, but instead detect gradients by measuring changes in concentration over time as they swim and delaying reorientations when swimming in a favorable direction (23). Searching animals, including humans, use information from paired sensory organs (eyes, ears, nares, antennae) to detect differentials in the strength of signals or the timing of signal arrival (11,100,101), which they use to decide which way to turn in response to a signal gradient (19,100). Groups of animals also respond to environmental gradients and do so in a coordinated fashion.…”

“…In Box 1, we describe parallels between the responses of single cells to chemical gradients, and the responses of single animals and animal groups to environmental gradients. The important point is that the use of spatial gradients is a fundamental part of the search strategies of cells like neutrophils (16) and bacteria (17), solitary animals like mice and fruit flies (18,19), and large animal groups like fish schools (20). In all cases, the searching individual or group has a means of measuring a signal differential (e.g., difference in signal strength or the timing of signal arrival between sensors) over space, and responding to that differential by altering locomotory behavior in a way that causes the individual or group to climb the gradient ( Fig.…”

Stable coexistence of ecologically identical species: conspecific aggregation via reproductive interference

“…Such variation is likely whenever detectability depends on the prevailing weather conditions, which may change rapidly. For example, carrion flies use olfactory cues to locate carcasses (Hammack et al 1987), and olfactory cues also play an important role in the foraging behaviour of fruit flies (Gaudry, Nagel & Wilson 2012). It is reasonable to assume that environmental conditions, such as moisture, temperature, exposure to sunlight, and the strength and direction of wind, will all affect the quality and quantity of the substances emitted from the resource patches and how the odours diffuse into the environment.…”

A Novel Approach for Solving Engineering Optimization Problems Involving Equality Constraints

“…The taste bristles and pegs have a terminal pore at the tip to allow direct access of food substances to the dendrite process of the gustatory receptor neuron (GRNs). The Drosophila also consisting with olfactory receptors [11] Proboscis has been modeled in to optimization algorithm and has been successfully used to solve unconstrained optimization problem in [8]. The beauty of this algorithm is it is robust and is parameter free.…”