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Multiple-Product Firms And Product Switching, Andrew B. Bernard, Stephen J. Redding, Peter K. Schott Mar 2010

Multiple-Product Firms And Product Switching, Andrew B. Bernard, Stephen J. Redding, Peter K. Schott

Dartmouth Scholarship

This paper examines the frequency, pervasiveness, and determinants of product switching by US manufacturing firms. We find that one-half of firms alter their mix of five-digit SIC products every five years, that product switching is correlated with both firm- and firm-product attributes, and that product adding and dropping induce large changes in firm scope. The behavior we observe is consistent with a natural generalization of existing theories of industry dynamics that incorporates endogenous product selection within firms. Our findings suggest that product switching contributes to a reallocation of resources within firms toward their most efficient use. (JEL L11, L21, L25, …


Antipredator Behavior And Physiology Determine Lestes Species Turnover Along The Pond-Permanence Gradient, Robby Stoks, Mark A. Mcpeek Dec 2003

Antipredator Behavior And Physiology Determine Lestes Species Turnover Along The Pond-Permanence Gradient, Robby Stoks, Mark A. Mcpeek

Dartmouth Scholarship

Identifying key traits that shape trade-offs that restrict species to only a subset of environmental gradients is crucial to understanding and predicting species turnover. Previous field experiments have shown that larvae of Lestes damselfly species segregate along the entire gradient of pond permanence and predator presence and that differential predation risk and life history constraints together shape their distribution. Here, we report laboratory experiments that identify key differences in behavior and physiology among species that structure their distributions along this gradient. The absence of adaptive antipredator behavioral responses against large dragonfly larvae and fish of Lestes dryas, the only species …


Predators And Life Histories Shape Lestes Damselfly Assemblages Along A Freshwater Habitat Gradient, Robby Stoks, Mark A. Mcpeek Jun 2003

Predators And Life Histories Shape Lestes Damselfly Assemblages Along A Freshwater Habitat Gradient, Robby Stoks, Mark A. Mcpeek

Dartmouth Scholarship

Survey data from New England showed that assemblages of Lestes damselflies are organized along the entire gradient of pond permanence and predator presence. One assemblage occupies vernal ponds lacking large dragonfly predators and fish; four are largely confined to temporary ponds that typically contain dragonfly predators; one dominates fishless permanent ponds and lakes where dragonflies are the top predators; and one dominates permanent ponds and lakes where fish are the top predators. We determined the role of life history and predation in maintaining this striking pattern by conducting a series of transplant experiments in the field and a laboratory experiment …


Predators And Life Histories Shape Lestes Damselfly Assemblages Along A Freshwater Habitat Gradient, Robby Stoks, Mark A. Mcpeek Oct 2002

Predators And Life Histories Shape Lestes Damselfly Assemblages Along A Freshwater Habitat Gradient, Robby Stoks, Mark A. Mcpeek

Dartmouth Scholarship

Survey data from New England showed that assemblages of Lestes dam- selflies are organized along the entire gradient of pond permanence and predator presence. One assemblage occupies vernal ponds lacking large dragonfly predators and fish; four are largely confined to temporary ponds that typically contain dragonfly predators; one dom- inates fishless permanent ponds and lakes where dragonflies are the top predators; and one dominates permanent ponds and lakes where fish are the top predators. We determined the role of life history and predation in maintaining this striking pattern by conducting a series of transplant experiments in the field and a …