3 results
Moth-inspired methods for particle capture on a cylinder
- Thomas L. Spencer, Nina Mohebbi, Guangyuan Jin, Matthew L. Forister, Alexander Alexeev, David L. Hu
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- Journal:
- Journal of Fluid Mechanics / Volume 884 / 10 February 2020
- Published online by Cambridge University Press:
- 17 December 2019, A34
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- Article
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We study particle capture on an angled cylinder at a range of Péclet numbers. This system was inspired by the plumose antennae of certain species of male moths that intercept female pheromones at low Péclet numbers of 0.9–23. We use confocal microscopy to measure the branching patterns of 49 moths, spanning 12 families and two orders of magnitude in mass. Among the three levels of hierarchy in antennae, we find the middle level has a prevalent branching angle, $52^{\circ }\pm 12^{\circ }$ across our study set. Such intermediate branching angles are a surprising way to intercept molecules because they do not maximize the exposed surface area. To understand the benefits of angling cylinders into the flow, we study particle collection at high Péclet number using $10~\unicode[STIX]{x03BC}\text{m}$ drops that are several orders of magnitude larger than moth pheromones. Wind tunnel tests show that cylinders angled at $30^{\circ }{-}60^{\circ }$ are optimal for collection of particles, collecting 30 % more than when perpendicular to the flow. Simulations and smoke visualization show that angled cylinders bend incoming streamlines, creating a lingering effect near the cylinder that can enhance deposition by diffusion. We surmise that the optimal angle arises from a trade-off between the lingering effect, which decreases with increasing angle of the cylinder, and the cylinder’s increasing projected area as it is turned more perpendicular to the flow. Using a mathematical model, we show that only cylinders at low Péclet number show improved collection at intermediate angles. Thus, we cannot rationalize the high collection rates in our wind tunnel experiments at high Péclet number. We hope that our study will inspire more research into bio-inspired particle collection of angled surfaces, and find applications in sensors and filters.
Human observers differ in ability to perceive insect diversity
- JOSEPH S. WILSON, JOSHUA P. JAHNER, MATTHEW L. FORISTER
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- Journal:
- Environmental Conservation / Volume 43 / Issue 4 / December 2016
- Published online by Cambridge University Press:
- 05 August 2016, pp. 376-380
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Human perception of biological variation is an important and understudied issue in the conservation and management of natural resources. Here, we took a novel approach by asking 1152 participants, primarily college biology students, to score examples of insect mimicry by the number of distinct kinds of animals they saw. Latent class analysis successfully separated participants based on their accuracy of perception as well as demographic information and opinions about biodiversity. Contrary to expectations, factors such as childhood experience (growing up in urban, suburban or rural areas) did not affect the ability to see biodiversity as much as political views (location on a spectrum from liberal to conservative) or the position that biodiversity is important for the health of the environment. We conclude that research into effective measures of biological education should consider the connection between personal views and perceptions of natural variation.
11 - The question of scale in trophic ecology
- from Part III - Patterns and Processes
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- By Lee A. Dye, University of Nevada, Tara J. Massad, University of Sao Paulo, Matthew L. Forister, University of Nevada
- Edited by Torrance C. Hanley, Northeastern University, Boston, Kimberly J. La Pierre, University of California, Berkeley
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- Book:
- Trophic Ecology
- Published online:
- 05 May 2015
- Print publication:
- 07 May 2015, pp 288-317
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Summary
Introduction
The thousands of studies on determinants and effects of top-down and bottom-up trophic forces (hereafter, TDBU) in aquatic and terrestrial communities include approaches that usually focus on specific scales; however, as a combined body of work, these studies span temporal scales from minutes to centuries and spatial scales from bench-top microcosms (cm3) to entire forests, lakes, or oceans (km3). How do empiricists synthesize this extensive literature and how do theorists calculate meaningful model parameters given these massive scale disparities? Levin (1992) argues that issues of scale are among the most important in ecology and perhaps all of the sciences, and there are both practical and theoretical reasons for using a variety of spatial and temporal scales in ecological studies. However, spatial and temporal scales are often ignored in syntheses of literature on trophic interactions. For example, a 4m2 plot and a 100 cm3 microcosm are the most appropriate scales for units of replication in experiments examining how arthropod foraging affects alpha diversity of primary producers in long leaf pine understories and ephemeral pool communities respectively, but these studies cannot in either case demonstrate population-level effects and should not be included in syntheses that examine top-down effects on beta diversity for entire forests or streams. In this chapter, we examine scaling issues associated with empirical studies of trophic interactions (for theoretical considerations, see Chapter 1, this volume).
We are interested in the extent to which processes and mechanisms observed at particular spatial and temporal scales are relevant for processes and patterns at other scales. To that end, we present examples of a concerted research effort with a model terrestrial system (ant-plants and associated rain forest communities), as well as multiple examples from freshwater and marine systems that have utilized a mix of experimental, observational, and modeling approaches across a continuum of spatial and temporal scales.