110 research outputs found

    Swimming Eastern Chipmunks, Tamias striatus, and Hairy-tailed Mole, Parascalops breweri, in Kawartha Highlands Provincial Park, Ontario

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    We report swimming Eastern Chipmunks, Tamias striatus, and a swimming Hairy-tailed Mole, Parascalops breweri, in southern Ontario in Kawartha Highlands Provincial Park. Although naturally swimming Eastern Chipmunks have been seen before, they have never been previously documented in the literature. Ours appears to be the first photograph of a swimming Hairy-tailed Mole and the first report of one successfully and apparently voluntarily swimming

    Maternal influences on early development: preferred temperature prior to oviposition hastens embryogenesis and enhances offspring traits in the Children’s python, <i>Antaresia childreni</i>

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    SUMMARY Embryonic life is particularly sensitive to its surroundings, and the developmental environment can have long-lasting effects on offspring. In oviparous species, the impacts of the developmental environment on offspring traits are mostly examined during development within the egg. However, as more than 25% of the development of squamate reptiles can occur prior to oviposition, we explored the effect of thermal conditions on development prior to oviposition in an oviparous snake species, the Children’s python (Antaresia childreni). We housed gravid female pythons under three thermal cycles: an optimal regime that reflected maternal preference in a non-constrained environment (constant preferred body temperature of gravid females, Tset=31.5°C) and two mildly suboptimal regimes that shared the same mean temperature of 27.7°C, but differed in the duration at Tset. In one of the constraining regimes, females had access to Tset for 4 h daily whereas in the other regime, females never reached Tset (maximal temperature of 29.0°C). Thermal treatments were maintained throughout gravidity in all three groups, but, after oviposition, all eggs were incubated at Tset until hatching. Compared with the optimal regime, the two suboptimal regimes had a longer duration of gravidity, which resulted in delayed hatching. Between the two suboptimal regimes, gravidity was significantly shorter in the treatment that included time at Tset. Furthermore, suboptimal regimes influenced offspring traits at hatching, including body morphology, antipredator behavior, strength and metabolism. However, partial access to maternal Tset significantly enhanced several offspring traits, including performance. Our results demonstrate the importance of time at Tset on early development and suggest an adaptive significance of maternal thermoregulation prior to oviposition.</jats:p

    Multi-Way Multi-Group Segregation and Diversity Indices

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    Background: How can we compute a segregation or diversity index from a three-way or multi-way contingency table, where each variable can take on an arbitrary finite number of values and where the index takes values between zero and one? Previous methods only exist for two-way contingency tables or dichotomous variables. A prototypical three-way case is the segregation index of a set of industries or departments given multiple explanatory variables of both sex and race. This can be further extended to other variables, such as disability, number of years of education, and former military service. Methodology/Principal Findings: We extend existing segregation indices based on Euclidean distance (square of coefficient of variation) and Boltzmann/Shannon/Theil index from two-way to multi-way contingency tables by including multiple summations. We provide several biological applications, such as indices for age polyethism and linkage disequilibrium. We also provide a new heuristic conceptualization of entropy-based indices. Higher order association measures are often independent of lower order ones, hence an overall segregation or diversity index should be the arithmetic mean of the normalized association measures at all orders. These methods are applicable when individuals selfidentify as multiple races or even multiple sexes and when individuals work part-time in multiple industries. Conclusions/Significance: The policy implications of this work are enormous, allowing people to rigorously test whethe

    Echinocereus reichenbachii subsp. Baileyi

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    Fishing for philosophical phylogenetic foibles

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    Book Review<b>Texas Cacti</b>by Brian Loflin and Shirley Loflin . Texas A &amp; M University Press, 2009. $24

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    Dracaena Draco<i>in Canada</i>

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    Wherefore stoch-aptation?

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    Echinomastus Intertextus

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    Wherefore stoch-aptation?

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    There exists discordance between different levels of evolution because the whole often differs from the sum of the parts. Yet, it is not obvious that the new term 'stoch-aptation' clarifies these differences between evolutionary levels, especially when this term seems largely equivalent to stochastic drift, to mega-evolution, and maybe even to phenotypic plasticity with extreme environments. But this new term forces us to carefully examine what evolutionary biologists mean by randomness, drift, selection, plasticity, and mega-evolution
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