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Full-Text Articles in Life Sciences
Ecological Boundary Detection Using Bayesian Areal Wombling, Joseph Elkinton, M. C. Fitzpatrick, E. L. Preisser, A. H. Porter, L. A. Wallwe, B. P. Carlin, A. M. Ellison
Ecological Boundary Detection Using Bayesian Areal Wombling, Joseph Elkinton, M. C. Fitzpatrick, E. L. Preisser, A. H. Porter, L. A. Wallwe, B. P. Carlin, A. M. Ellison
Joseph Elkinton
The study of ecological boundaries and their dynamics is of fundamental importance to much of ecology, biogeography, and evolution. Over the past two decades, boundary analysis (of which wombling is a subfield) has received considerable research attention, resulting in multiple approaches for the quantification of ecological boundaries. Nonetheless, few methods have been developed that can simultaneously (1) analyze spatially homogenized data sets (i.e., areal data in the form of polygons rather than point-reference data); (2) account for spatial structure in these data and uncertainty associated with them; and (3) objectively assign probabilities to boundaries once detected. Here we describe the …
Exploitative Competition Between Invasive Herbivores Benefits A Native Host Plant, Joseph Elkinton, E. L. Preisser
Exploitative Competition Between Invasive Herbivores Benefits A Native Host Plant, Joseph Elkinton, E. L. Preisser
Joseph Elkinton
Although biological invasions are of considerable concern to ecologists, relatively little attention has been paid to the potential for and consequences of indirect interactions between invasive species. Such interactions are generally thought to enhance invasives' spread and impact (i.e., the “invasional meltdown” hypothesis); however, exotic species might also act indirectly to slow the spread or blunt the impact of other invasives. On the east coast of the United States, the invasive hemlock woolly adelgid (Adelges tsugae, HWA) and elongate hemlock scale (Fiorinia externa, EHS) both feed on eastern hemlock (Tsuga canadensis). Of the two insects, HWA is considered far more …
Implicating An Introduced Generalist Parasitoid In The Invasive Browntail Moth's Enigmatic Demise, Joseph Elkinton, D. Parry, G. Boettner
Implicating An Introduced Generalist Parasitoid In The Invasive Browntail Moth's Enigmatic Demise, Joseph Elkinton, D. Parry, G. Boettner
Joseph Elkinton
Recent attention has focused on the harmful effects of introduced biological control agents on nontarget species. The parasitoid Compsilura concinnata is a notable example of such biological control gone wrong. Introduced in 1906 primarily for control of gypsy moth, Lymantria dispar, this tachinid fly now attacks more than 180 species of native Lepidoptera in North America. While it did not prevent outbreaks or spread of gypsy moth, we present reanalyzed historical data and experimental findings suggesting that parasitism by C. concinnata is the cause of the enigmatic near-extirpation of another of North America's most successful invaders, the browntail moth (Euproctis …
Measuring And Testing For Spacial Synchrony, Joseph Elkinton, W. A. Ruscoe, D. Choquenot, R. B. Allen
Measuring And Testing For Spacial Synchrony, Joseph Elkinton, W. A. Ruscoe, D. Choquenot, R. B. Allen
Joseph Elkinton
Spatial synchrony in abundance among populations at different locations has been studied for many species. Different statistics have been used as measures of synchrony, and various techniques have been employed to test the hypothesis that there is no synchrony. In this paper we first describe and contrast various measures of synchrony and then discuss testing for no synchrony. Tests that ignore the serial correlation are commonly employed but are incorrect if there is serial correlation present, as is often the case with populations followed over time. Alternative approaches and their limitations are presented including tests based on residuals, adjusted degrees …
Effects Of Synchrony With Host Plant On Population Of A Spring-Feeding Lepidopteran, Joseph Elkinton, A. F. Hunter
Effects Of Synchrony With Host Plant On Population Of A Spring-Feeding Lepidopteran, Joseph Elkinton, A. F. Hunter
Joseph Elkinton
Comparisons of traits of outbreaking and nonoutbreaking leaf-eating Lepidoptera and Symphyta have shown that spring-feeding species are more likely to have outbreaks than are summer-feeding species. It has been suggested that variable synchrony with host budburst causes the population sizes of spring-feeding species to be more variable primarily because of the negative effects of older leaves on insects. While much evidence exists that leaf age can directly affect survival and reproduction of insects, few studies have looked at the population-level effects of variable phenology, and especially the potential for complex direct and indirect interactions with natural-enemy effects. To examine the …
Foliage Damage Does Not Affect Within-Season Transmission Of Am Insect Virus, Joseph Elkinton, V. D'Amico, G. Dwyer, R. B. Willis, M. E. Montgomery
Foliage Damage Does Not Affect Within-Season Transmission Of Am Insect Virus, Joseph Elkinton, V. D'Amico, G. Dwyer, R. B. Willis, M. E. Montgomery
Joseph Elkinton
Gypsy moth defoliation of oak trees has been shown to lead to increased tannin levels, which, in turn, lead to reduced gypsy moth growth and fecundity. In laboratory experiments, increased tannin levels can interfere with the transmission of a virus that is consumed by larvae on oak foliage, and high mortality rates of larvae in the field are sometimes associated with low levels of defoliation. These latter results have led to the suggestion that gypsy moth defoliation may cause reduced mortality attributable to the virus by elevating oak tannin levels. In a series of field experiments, we directly tested the …
Material Effects In Gypsy Moth: Only Sex Ratio Varies With Population Density, Joseph Elkinton, J. H. Myers, G. Boettner
Material Effects In Gypsy Moth: Only Sex Ratio Varies With Population Density, Joseph Elkinton, J. H. Myers, G. Boettner
Joseph Elkinton
A number of species of forest caterpillars fluctuate in density with a periodicity of 8–11 yr. One explanation for these “cycles” is that changes in food quality or quantity and crowding influence the growth rate and final size of moths at high density. Carryover of these influences to the next generation through maternal effects could modify the dynamics of the population. To determine whether development, survival, pupal size, fecundity, or sex ratio varied among offspring of gypsy moths from high- and low-density populations, we collected eggs from three sites where moths had been at low density and three sites where …