Benthic-Pelagic Links and Rocky Intertidal Communities: Bottom-Up Effects on Top-Down Control?

Insight into the dependence of benthic communities on biological and physical processes in nearshore pelagic environments, long considered a ``black box,'' has eluded ecologists. In rocky intertidal communities at Oregon coastal sites 80 km apart, differences in abundance of sessile invertebrates, herbivores, carnivores, and macrophytes in the low zone were not readily explained by local scale differences in hydrodynamic or physical conditions (wave forces, surge flow, or air temperature during low tide). Field experiments employing predator and herbivore manipulations and prey transplants suggested top-down (predation, grazing) processes varied positively with bottom-up processes (growth of filter-feeders, prey recruitment), but the basis for these differences was unknown. Shore-based sampling revealed that between-site differences were associated with nearshore oceanographic conditions, including phytoplankton concentration and productivity, particulates, and water temperature during upwelling. Further, samples taken at 19 sites along 380 km of coastline suggested that the differences documented between two sites reflect broader scale gradients of phytoplankton concentration. Among several alternative explanations, a coastal hydrodynamics hypothesis, reflecting mesoscale (tens to hundreds of kilometers) variation in the interaction between offshore currents and winds and continental shelf bathymetry, was inferred to be the primary underlying cause. Satellite imagery and offshore chlorophyll-a samples are consistent with the postulated mechanism. Our results suggest that benthic community dynamics can be coupled to pelagic ecosystems by both trophic and transport linkages.KEYWORDS: scale, productivity, currents, upwelling, community structureThis is the publisher’s final pdf. The published article is copyrighted by the National Academy of Sciences of the United States of America and can be found at: http://www.pnas.org

Differences in the Aerobic Capacity of Flight Muscles between Butterfly Populations and Species with Dissimilar Flight Abilities

Habitat loss and climate change are rapidly converting natural habitats and thereby increasing the significance of dispersal capacity for vulnerable species. Flight is necessary for dispersal in many insects, and differences in dispersal capacity may reflect dissimilarities in flight muscle aerobic capacity. In a large metapopulation of the Glanville fritillary butterfly in the Åland Islands in Finland, adults disperse frequently between small local populations. Individuals found in newly established populations have higher flight metabolic rates and field-measured dispersal distances than butterflies in old populations. To assess possible differences in flight muscle aerobic capacity among Glanville fritillary populations, enzyme activities and tissue concentrations of the mitochondrial protein Cytochrome-c Oxidase (CytOx) were measured and compared with four other species of Nymphalid butterflies. Flight muscle structure and mitochondrial density were also examined in the Glanville fritillary and a long-distance migrant, the red admiral. Glanville fritillaries from new populations had significantly higher aerobic capacities than individuals from old populations. Comparing the different species, strong-flying butterfly species had higher flight muscle CytOx content and enzymatic activity than short-distance fliers, and mitochondria were larger and more numerous in the flight muscle of the red admiral than the Glanville fritillary. These results suggest that superior dispersal capacity of butterflies in new populations of the Glanville fritillary is due in part to greater aerobic capacity, though this species has a low aerobic capacity in general when compared with known strong fliers. Low aerobic capacity may limit dispersal ability of the Glanville fritillary.Peer reviewe

Inferring the past and present connectivity across the range of a North American leaf beetle: combining ecological-niche modeling and a geographically explicit model of coalescence

The leaf beetle Chrysomela aeneicollis occurs across Western North America, either at high elevation or in small, isolated populations along the coast, and thus has a highly fragmented distribution. DNA sequence data (three loci) were collected from five regions across the species range. Population connectivity was examined using traditional ecological niche modeling, which suggested that gene flow could occur among regions now and in the past. We developed geographically explicit coalescence models of sequence evolution that incorporated a two-dimensional representation of the hypothesized ranges suggested by the niche-modeling estimates. We simulated sequence data according to these models and compared them to observed sequences to identify most probable scenarios regarding the migration history of C. aeneicollis. Our results disagreed with initial niche-modeling estimates by clearly rejecting recent connectivity among regions, and were instead most consistent with a long period of range fragmentation, extending well beyond the last glacial maximum. This application of geographically explicit models of coalescence has highlighted some limitations of the use of climatic variables for predicting the present and past range of a species and has explained aspects of the Pleistocene evolutionary history of a cold-adapted organism in Western North America. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution..SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Mitonuclear mismatch alters performance and reproductive success in naturally-introgressed populations of a montane leaf beetle

info:eu-repo/semantics/inPres

Differences in body size and ecological characteristics of the Nymphalid butterflies compared in this study.

<p><b>References.</b></p><p>¹ . <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Sutcliffe1" target="_blank">[59]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Billeter1" target="_blank">[61]</a>;</p><p>² . <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Aarnio1" target="_blank">[62]</a>;</p><p>³ . <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Hanski2" target="_blank">[20]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Austin1" target="_blank">[63]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Wang1" target="_blank">[65]</a>;</p><p>⁴ . <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Hanski2" target="_blank">[20]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Ovaskainen1" target="_blank">[22]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Hanski4" target="_blank">[23]</a>;</p><p>⁵ . <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Vandewoestijne2" target="_blank">[66]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Shreeve1" target="_blank">[67]</a>;</p><p>⁶ . <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Asher1" target="_blank">[68]</a>;</p><p>⁷ . <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Wilson1" target="_blank">[69]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Asher2" target="_blank">[70]</a>;</p><p>⁸ . <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Asher1" target="_blank">[68]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Asher2" target="_blank">[70]</a>;</p><p>⁹ . <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Stefanescu1" target="_blank">[71]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Mikkola1" target="_blank">[73]</a>;</p><p>¹⁰ . <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078069#pone.0078069-Brattstrom1" target="_blank">[74]</a>.</p

Mitochondrial structure and density in the flight muscles of two butterfly species with dissimilar flight behaviours.

<p>(A) Microscopic images of flight muscle of the Glanville fritillary (a, c) and the Red Admiral (b, d). Mitochondria (m and arrows), sarcoplasmic reticulum (s) and myofibrils (my) are indicated. Bars are 500 nm in a and b, 1 µm in c and d. (B) Distribution of mitochondrial profiles from thin sections of the flight muscle.</p