Foraging behavior of migrant warblers in mixed‐species flocks in Venezuelan shade coffee: interspecific differences,tree species selection,and effects of drought

Shade coffee has been identified as an important habitat for Nearctic‐Neotropical migrants during the non‐breeding season, including species of conservation concern such as Cerulean Warblers (Setophaga cerulea). To better understand habitat features important for migrants in shade coffee, we studied the foraging behavior of migrants in mixed‐species flocks at six shade‐coffee farms in the Cordillera de Merida, Venezuela, in 2008–2009 and the El Niño drought year of 2009–2010. We examined interspecific differences in foraging behavior and tree species selection of three foliage‐gleaning migrants, Blackburnian (Setophaga fusca), Cerulean, and Tennessee (Oreothlypis peregrina) warblers, and aerial‐foraging American Redstarts (Setophaga ruticilla). For morphologically similar Blackburnian and Cerulean warblers, we also examined factors influencing foraging rates (attack and movement rates), capture of large prey, and maneuver/substrate type. We found that aerial‐foraging American Redstarts foraged lower, used more aerial maneuvers, showed no tree species selection, and were less likely to forage in flocks than foliage‐gleaners. Although foraging rates were similar for Blackburnian and Cerulean warblers, the three foliage‐gleaners differed in foraging height and use of maneuvers. Cerulean Warblers foraged lower than the other two species, whereas Blackburnian Warblers used the greatest proportion of woody gleans. All three foliage‐gleaners selected Inga spp. (a commonly planted shade tree in shade‐coffee farms) for foraging, and Blackburnian and Cerulean warblers captured a greater proportion of large prey in Inga spp. than in other tree species. During the drought year, Blackburnian and Cerulean warblers captured half as many large prey and used a greater proportion of woody‐gleans. We found that interactions among behavioral, floristic, and environmental drivers influenced the foraging behavior of migrants wintering in shade coffee. Our results support those of previous studies suggesting that migrants partition resources behaviorally during the non‐breeding season, that foliage‐gleaners may benefit from the presence of shade trees, especially Inga spp., in agroforestry systems, and that drought may influence the foraging behavior of foliage‐gleaning migrants, presumably due to reduced prey availability.     

Humoral and cellular immune reactions against tumor cells in patients with urinary bladder carcinoma

Serum IgG fractions from a large and homogeneous group of patients with transitional cell carcinoma of the urinary bladder (TCC) were tested for their capacity to induce antibody-dependent cellular cytotoxicity (ADCC) with lymphocytes from healthy donors against a TCC-derived target cell and one derived from adenocarcinoma of the colon. Both targets have previously been shown to be of comparable susceptibility to cell-mediated lysis in vitro. Some of the IgG preparations showed strong and dose-dependent ADCC against either one or both targets, while others gave weak reactions or none at all. Similar results were obtained with IgG from a matched group of patients with prostatic carcinoma who were used as clinical controls (CC). In parallel experiments, lymphocytes taken from the two donor groups at the same time as the serum samples were tested for their direct cytotoxicity (CMC) against the two targets. CMC gave similar results to ADCC. The differences in cytotoxicity displayed by either IgG or lymphocytes from individual donors were analysed statistically, using nonparametric statistics. To avoid introducing bias due to arbitrary data selection, the entire set of results, comprising both high and low reactors, was included in the statistical assessment. ADCC of the TCC donors' IgG against the TCC target was significantly stronger than against the colon carcinoma and also significantly stronger than that of the control donors. Similarly, the TCC patients' lymphocytes displayed a significantly higher CMC against the TCC target than against the control targets. This was not seen when the lymphocytes from the patients with prostatic carcinoma were tested. When CMC and ADCC of individual donors were compared, a statistically significant correlation between these activities was seen in three of the four donor/target combinations. These results support earlier findings and suggest that a significant fraction of both the disease-related and the 'non-selective' CMC (NK) displayed by cancer patients lymphocytes against allogeneic tumor cells in vitro reflects antibody-dependent reactions.     

Mitochondrial substrate specificity in beetle flight muscle: assessing respiratory oxygen flux in small samples from Dermestes maculatus and Tenebrio molitor

In the present study, the permeabilized fibre approach is adapted to investigate substrate utilization patterns in the flight muscle mitochondria of Dermestes maculatus (Coleoptera: Dermestidae; a carrion scavenger beetle) and Tenebrio molitor (Coleoptera: Tenebrionidae; a phytophagous scavenger beetle). Respiration in saponin‐permeabilized fibres is measured during titration of palmitoyl‐carnitine (Palm‐C), pyruvate (Pyr) or l ‐glycerol 3‐phosphate (G3‐P). Michaelis–Menten‐type enzyme kinetics for oxygen consumption are observed as a function of substrate concentration in Pyr and G3‐P, from which substrate‐specific apparent K_m (sensitivity) and V_max (capacity) are determined. Compared with D. maculatus, the apparent K_m in T. molitor is lower (P < 0.001) for Pyr, and V_max is greater for G3‐P (P < 0.001). In D. maculatus, the apparent K_m for G3‐P is greater (P < 0.001), and respiratory V_max is lower (P < 0.001), than kinetics for Pyr. Robust respiration with l ‐proline (Pro) is also observed in both beetle species tested; however, it is over 2.5‐fold greater in D. maculatus than T. molitor (P < 0.05). These results demonstrate that respiration in beetle flight muscle mitochondria can be assessed in small samples (i.e. at the individual beetle level) using the approach adapted for the present study. The results of the present study also highlight the substrate oxidative capacity patterns in both D. maculatus and T. molitor, which rank Palm‐C < G3‐P < Pyr < Pro.     

Four-component power spectral density model of steady-state isometric force

The aim of this study was to develop and evaluate a model based upon four identified characteristics of the power spectral density associated with isometric force at a range of constant force levels (5–95% maximum voluntary contraction). The characteristics modeled were: (1) a low-frequency resonant peak located at about 1 Hz; (2) a region of 1/f-like fractional Gaussian noise (fGn); (3) the resonant peak in the 8–12 Hz region on the PSD; and (4) Gaussian white noise resulting from a combination of neural as well as equipment noise. When superimposed, these components were used in a direct fit to the isometric force data to generate a linear predictor that resulted in residual values on the order of the white noise present in the original force time series.