Publications by authors named "Zachary G MacDonald"

We describe a highly contiguous and complete diploid genome assembly for the Chryxus Arctic, Oeneis chryxus (E. Doubleday, [1849]), a butterfly species complex spanning much of northern and western North America. One subspecies, the Ivallda Arctic (O.

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Damselflies and dragonflies (Order: Odonata) play important roles in both aquatic and terrestrial food webs and can serve as sentinels of ecosystem health and predictors of population trends in other taxa. The habitat requirements and limited dispersal of lotic damselflies make them especially sensitive to habitat loss and fragmentation. As such, landscape genomic studies of these taxa can help focus conservation efforts on watersheds with high levels of genetic diversity, local adaptation, and even cryptic endemism.

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Article Synopsis
  • Recent advancements in landscape ecology and DNA sequencing allow for the analysis of gene flow and genomic variation influenced by geographic and environmental factors.
  • The study focuses on the forest tent caterpillar in Eastern Canada, exploring how environmental gradients and host tree species impact genomic differentiation.
  • Findings indicate that gene variation among caterpillars is influenced by distance, environmental conditions, and host associations, highlighting the importance of ecologically mediated selection in this pest's adaptation and management.
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Article Synopsis
  • Recent advancements in genomics and ecological modeling are being used to clarify species boundaries and understand how these boundaries are maintained, specifically in the Speyeria atlantis-hesperis butterfly complex in North America.
  • The study utilized DNA sequencing and ecological niche modeling to uncover significant genetic divergences between the species S. atlantis and S. hesperis, as well as within S. hesperis itself, revealing evidence of historical gene flow with another species, S. zerene.
  • Results indicate that the three distinct genetic lineages have diverged ecologically, suggesting that differing habitat associations rather than geographical barriers are driving the maintenance of their genomic integrity, leading to the recognition of one lineage, S. nausicaa, as a
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Temporal separation of reproductive timing can contribute to species diversification both through allochronic speciation and later reinforcement of species boundaries. Such phenological differences are an enigmatic component of evolutionary divergence between two major forest defoliator species of the spruce budworm complex: and . While these species interbreed freely in laboratory settings, natural hybridization rates have not been reliably quantified due to their indistinguishable morphology.

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Previous work in landscape genetics suggests that geographic isolation is of greater importance to genetic divergence than variation in environmental conditions. This is intuitive when configurations of suitable habitat are a dominant factor limiting dispersal and gene flow, but has not been thoroughly examined for habitat specialists with strong dispersal capability. Here, we evaluate the effects of geographic and environmental isolation on genetic divergence for a vagile invertebrate with high habitat specificity and a discrete dispersal life stage: Dod's Old World swallowtail butterfly, Papilio machaon dodi.

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Butterflies are widely invoked as model organisms in studies of metapopulation and dispersal processes. Integral to such investigations are understandings of perceptual range; the maximum distance at which organisms are able to detect patches of suitable habitat. To infer perceptual range, researchers have released butterflies at varying distances from habitat patches and observed their subsequent flight behaviors.

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Since the publication of the theory of island biogeography, ecologists have postulated that fragmentation of continuous habitat presents a prominent threat to species diversity. However, negative fragmentation effects may be artifacts; the result of species diversity declining with habitat loss, and habitat loss correlating positively with degree of fragmentation. In this study, we used butterfly assemblages on islands of Lake of the Woods, Ontario, Canada to decouple habitat fragmentation from habitat loss and test two competing hypotheses: (1) the island effect hypothesis, which predicts that decreasing fragment size and increasing fragment isolation reduces species diversity beyond the effects of habitat loss, and (2) the habitat amount hypothesis, which negates fragmentation effects and predicts that only total habitat area determines the diversity of species persisting on fragmented landscapes.

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