Variation in scorpion metabolic rate and rate–temperature relationships : implications for the fundamental equation of the metabolic theory of ecology

CITATION: Terblanche, J.S., Janion, C. & Chown, S.L. 2007. Variation in scorpion metabolic rate and rate–temperature relationships: implications for the fundamental equation of the metabolic theory of ecology. Journal of Evolutionary Biology, 20(4):1602-1612. doi:10.1111/j.1420-9101.2007.01322.xThe original publication is available at https://onlinelibrary.wiley.com/journal/14209101The fundamental equation of the metabolic theory of ecology (MTE) indicates that most of the variation in metabolic rate are a consequence of variation in organismal size and environmental temperature. Although evolution is thought to minimize energy costs of nutrient transport, its effects on metabolic rate via adaptation, acclimatization or acclimation are considered small, and restricted mostly to variation in the scaling constant, b0. This contrasts strongly with many conclusions of evolutionary physiology and life-history theory, making closer examination of the fundamental equation an important task for evolutionary biologists. Here we do so using scorpions as model organisms. First, we investigate the implications for the fundamental equation of metabolic rate variation and its temperature dependence in the scorpion Uroplectes carinatus following laboratory acclimation. During 22 days of acclimation at 25C metabolic rates declined significantly (from 127.4 to 78.2 uW; P = 0.0001) whereas mean body mass remained constant (367.9–369.1 mg; P = 0.999). In field-fresh scorpions, metabolic rate–temperature (MRT) relationships varied substantially within and among individuals, and therefore had low repeatability values (r ~ 0.02) and no significant among-individual variation (P = 0.181). However, acclimation resulted in a decline in withinindividual variation of MRT slopes which subsequently revealed significant differences among individuals (P = 0.0031) and resulted in a fourfold increase in repeatability values (r = 0.08). These results highlight the fact that MRT relationships can show substantial, directional variation within individuals over time. Using a randomization model we demonstrate that the reduction in metabolic rate with acclimation while body mass remains constant causes a decline both in the value of the mass-scaling exponent and the coefficient of determination. Furthermore, interspecific comparisons of activation energy, E, demonstrated significant variation in scorpions (0.09–1.14 eV), with a mean value of 0.77 eV, significantly higher than the 0.6–0.7 eV predicted by the fundamental equation. Our results add to a growing body of work questioning both the theoretical basis and empirical support for the MTE, and suggest that alternative models of metabolic rate variation incorporating explicit consideration of life history evolution deserve further scrutiny.NIH grant AI-52456 to E.S.Krafsur NRF grant FA2004032000006 to S.L. ChownPublisher’s versio

Cryptic species, biogeographic complexity and the evolutionary history of the Ectemnorhinus group in the sub-Antarctic, including a description of Bothrometopus huntleyi, n. sp.

The biogeography of the South Indian Ocean Province (SIP) biotas has long been controversial. Much of the discussion has been based on interpretation of species distributions, based on morphological or anatomical delimitations. However, molecular phylogenetic approaches elsewhere have recently shown that interpretations based solely on morphological data may be misleading. Nonetheless, few studies have employed molecular phylogenetic approaches to understand the biogeography of the SIP biotas. We do so here for the Ectemnorhinus group of genera, a monophyletic unit of weevils endemic to the region. We use mitochondrial cytochrome oxidase I DNA sequence data to reconstruct relationships among 13 species and 22 populations in the genera Palirhoeus, Bothrometopus and Ectemnorhinus. On the basis of this analysis we find little support for separating the genus Palirhoeus from Bothrometopus, and little support for the morphologically-based species groups currently recognized within Bothrometopus. Using a molecular clock we show that dispersal among islands probably took place against the prevailing wind direction. These data also support a previous hypothesis of radiation of the epilithic genera Bothrometopus and Palirhoeus during the Pliocene/early Pleistocene, but reject the hypothesis that the genus Ectemnorhinus radiated following the last glacial maximum. We show that Bothrometopus parvulus (C.O. Waterhouse) on the Prince Edward Islands comprises two species that are not sister taxa.We name the second species Bothrometopus huntleyi n. sp. and provide a description thereof.http://journals.cambridge.org/action/displayJournal?jid=an

Inter-island dispersal of flightless Bothrometopus huntleyi (Coleoptera: Curculionidae) from the sub-Antarctic Prince Edward Island archipelago

Bothrometopus huntleyi is a flightless weevil endemic to the volcanically-formed sub-Antarctic Prince Edward Islands archipelago that arose approximately 0.5 million years ago (m.y.a.). Since emergence, a series of volcanic and glaciation events have occurred on Marion Island, whilst Prince Edward Island, the second island constituting the archipelago, has remained largely unaffected by glaciation. Cytochrome oxidase I gene analyses indicate that major historical dispersal events in this species are linked to the geologically discrete histories of these islands and underlie the high haplotype diversity (0.995) recovered for the Prince Edward Islands archipelago. The estimated time to haplotype coalescence of,0.723 m.y.a. is in keeping with estimated dates of island emergence, and the majority of individuals appear to have descended from a relict, high-altitude population that is still present on Marion Island. The first major inter-island dispersal event occurred,0.507 m.y.a., coinciding with the oldest dated rocks on Marion Island. Apart from this early inter-island colonization, only one other between-island dispersal event was detected. The genetically discrete B. huntleyi complexes on each of the islands of the Prince Edward Islands archipelago together with the low levels of inter-island gene flow reaffirm the need to control alien invasive mice, which are restricted to Marion Island, and which prey on this weevil species.http://journals.cambridge.org/action/displayJournal?jid=an

A new specific plant host for the agave snout weevil, Scyphophorus acupunctatus Gyllenhal, 1838 (Coleoptera : Curculionidae) in South Africa : a destructive pest of species of Agave L. (Agavaceae)

The widely distributed agave snout weevil, Scyphophorus acupunctatus Gyllenhal, is for the first time recorded from Agave salmiana Otto ex Salm-Dyck subsp. salmiana in South Africa. In its native habitat in Mexico, this new host plant species is one of the most important sources of pulque, a fermented alcoholic beverage. With efforts underway at Bothaville in the Free State Province, South Africa, to establish an agave nectar industry, commercial farmers should be made aware of the destruction that the agave weevil can cause, especially in concentrated populations and plantations of Agave L. species.Der weit verbreitete Agaven- Rüsselkäfer Scyphophorus acupunctatus Gyllenhal wird zum ersten Mal für Agave salmiana Otto ex Salm-Dyck subsp. salmiana in Südafrika nachgewiesen. Die Heimat des Käfers ist Mexiko, und die neu nachgewiesene Wirtspflanze ist eine der wichtigsten Grundlagen für die Herstellung des alkoholischen Getränkes Pulque. Mit Blick auf die Versuche, in Bothaville in der Free State-Provinz, Südafrika, eine Agavensaft-Industrie aufzubauen, müssen die kommerziellen Pflanzer für die Schäden sensibilisiert werden, die der Käfer vor allem in dichten Populationen und Plantagen von Agave-Arten anrichten kann.http://www.bcss.org.uk/journal.htmlam201

A roadmap for Antarctic and Southern Ocean science for the next two decades and beyond

Antarctic and Southern Ocean science is vital to understanding natural variability, the processes that govern global change and the role of humans in the Earth and climate system. The potential for new knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic community came together to ‘scan the horizon’ to identify the highest priority scientific questions that researchers should aspire to answer in the next two decades and beyond. Wide consultation was a fundamental principle for the development of a collective, international view of the most important future directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific questions through structured debate, discussion, revision and voting. Questions were clustered into seven topics: i)Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world, iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond, and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require innovative experimental designs, novel applications of technology, invention of next-generation field and laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples. Sustained year-round access toAntarctica and the Southern Ocean will be essential to increase winter-time measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the Earth System, and provide predictions at spatial and temporal resolutions useful for decision making. A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration, will be essential as no scientist, programme or nation can realize these aspirations alone.Tinker Foundation, Antarctica New Zealand, The New Zealand Antarctic Research Institute, the Scientific Committee on Antarctic Research (SCAR), the Council of Managers of National Antarctic Programs (COMNAP), the Alfred Wegner Institut, Helmholtz Zentrum für Polar und Meeresforschung (Germany), and the British Antarctic Survey (UK).http://journals.cambridge.org/action/displayJournal?jid=ANShb201

Local scale comparisons of biodiversity as a test for global protected area ecological performance: a meta-analysis

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Improving human and environmental health in urban informal settlements:the Revitalising Informal Settlements and their Environments (RISE) programme

Daniel Reidpath - ORCID: 0000-0002-8796-0420 https://orcid.org/0000-0002-8796-0420https://doi.org/10.1016/S2542-5196(18)30114-12pubpubSuppl