Niche partitioning as a selective pressure for the evolution of theDrosophilanervous system

Abstract

The ecological and developmental selective pressures associated with evolution have shaped most animal traits, such as behavior, morphology and neurobiology. As such, the examination of phylogenetic characteristics of the nervous system can be utilized as a means to assess these traits, and thus, to evaluate the underlying selective pressures that produce evolutionary variation between species. Recent studies across a multitude of Drosophila have hypothesized the existence of a fundamental tradeoff between two primary sensory organs, the eye and the antenna. However, the identification of any potential ecological mechanisms for this observed tradeoff have not been firmly established. Our current study examines two monophyletic species within the obscura group, and asserts that despite their close relatedness and overlapping ecology, they deviate strongly in both visual and olfactory investment. Here we contend that both courtship and microhabitat preferences mirror and support the observed inverse variation in these sensory traits. Moreover, that this variation in visual and olfactory investment between closely-related species seems to provide relaxed competition, a process by which similar species can use a shared environment differently and in ways that help them both coexist. The nervous system has a unique role in evolution as it provides the functional connection between morphology, physiology, and behavior. As such, characterizing any tradeoffs between costs and benefits for the nervous system may be essential to our understanding of animal diversity, as well as vital to our understanding of the selective forces that have shaped the natural world.

Evolution of a pest: towards the complete neuroethology of Drosophila suzukii and the subgenus Sophophora

“…com) and were of the highest purity available. Stimuli preparation and delivery for electrophysiological experiments followed previously established procedures, and any headspace collection of plant, fruit or microbial volatile odors was carried out according to standard procedures 10,60 . For SSR experiments, 10µl of a dilution (10 -4 in hexane) of an odor was loaded onto a filter paper disc that was placed inside a glass pipette.…”

Neural divergence and hybrid disruption between ecologically isolatedHeliconiusbutterflies

“…Whether brains respond to changes in broader features of the environment, such as luminance or habitat structure, at a similar time scale is yet to be established. Recently, studies of closely related populations on the path to speciation have begun to address this question [11,13,23,24]. Importantly, however, these studies are often unable to disentangle the effects of drift and selection, and have not determined whether hybrids between ecologically distinct populations show disrupted or intermediate brain morphologies that may betray major fitness deficits, and therefore support a more causative role for divergence in neural systems during the incipient stages of speciation.…”

Functional olfactory evolution in Drosophila suzukii and the subgenus Sophophora

“…It is important to note that the persistent dearth of viable ecological and natural history information for the majority of the known Drosophila species makes the subsequent extrapolation toward evolutionary pressures, ecological mechanisms, or roles of niche partitioning difficult ( Keesey et al., 2019c , 2020 ). This paucity of ecological and host information leaves several species without known ligands for either ab2B or ab3A, despite a chemically diverse and robust screening of these OSNs in the present study using known host materials from other members of this subgenus.…”