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Little is known about the ecology of insect species in the hyporheic zone of rivers, despite its importance in understanding how species survive in specialized habitats. We report on the life history and trophic characteristics of the hyporheic stonefly species Alloperla ishikariana Kohno, 1953 (Order: Plecoptera, Family: Chloroperlidae) in a gravel-bed river in northern Japan, using year-round sampling of both benthic and hyporheic larvae, as well as flying adults in the riparian zone. Adults emerged between May and August, and the larval cohort structure consisted of three sized groups with some sex dimorphism in their body size, with an average growth rate of 0.0043 mg/day. Diet analyses based on C and N stable isotope ratios indicated minimal ontogenetic diet shifts. In contrast, the temporal diet shift was more apparent with higher dependence on Oligochaeta in winter, with an increasing dependence on Chironomidae in spring and early summer. Other insect taxa, namely, Leuctridae and small-sized Lepidostoma, demonstrated a high to moderate affinity for the hyporheic zone. Alloperla ishikariana spent most of its larval stage in the hyporheic zone. With adults living from 7 to 10 days, A. ishikariana completes a life span of approximately 3 years with its larval stage in the dark. [ABSTRACT FROM AUTHOR]

Classical simultaneous confidence bands for survival functions (i.e., Hall–Wellner, equal precision, and empirical likelihood bands) are derived from transformations of the asymptotic Brownian nature of the Nelson–Aalen or Kaplan–Meier estimators. Due to the properties of Brownian motion, a theoretical derivation of the highest confidence density region cannot be obtained in closed form. Instead, we provide confidence bands derived from a related optimization problem with local time processes. These bands can be applied to the one-sample problem regarding both cumulative hazard and survival functions. In addition, we present a solution to the two-sample problem for testing differences in cumulative hazard functions. The finite sample performance of the proposed method is assessed by Monte Carlo simulation studies. The proposed bands are applied to clinical trial data to assess survival times for primary biliary cirrhosis patients treated with D-penicillamine. [ABSTRACT FROM AUTHOR]

Physiological constraints can limit thermal niche breadth in organisms, particularly for small-bodied ectotherms. Daily temperature fluctuations often surpass annual (seasonal) temperature variation in the tropics, suggesting diel temperature cycles could drive thermal specialization by individuals that are active at different times of the day. We used foraging workers of the Neotropical ant Ectatomma ruidum to assess whether diurnally and nocturnally active workers differed in thermal tolerance. We compared critical thermal maxima (CT) of nocturnal and diurnal foraging workers to explore thermal niche specialization over the diel cycle. We predicted that diurnally active workers would have higher CT because they occupy a warmer thermal niche. As predicted, diurnal foragers exhibited significantly higher CT (mean 1.1 °C difference) than nocturnal foragers. Diurnal and nocturnal foragers were similar in body size, and there was no relationship between worker size and CT. We discuss possible mechanisms for this pattern, and the implications of within- versus between-colony differences in CT. [ABSTRACT FROM AUTHOR]