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Manjarrez J.,National Autonomous University of Mexico | Rivas-Gonzalez E.,National Autonomous University of Mexico | Venegas-Barrera C.S.,Technological Institute of Ciudad Victoria | Moyaho A.,Autonomous University of Puebla
PLoS ONE | Year: 2015

Semi-aquatic snakes integrate visual and chemical stimuli, and prey detection and capture success are therefore linked to the display of visual predatory behavior. The snake Thamnophis melanogaster responds preferentially to individuals of the fish Xenotoca variata with a greater number of bright, colorful spots (lateral speckles) compared with those with a smaller number; however, water turbidity can reduce underwater visibility and effect the vulnerability of fish. In this study, we tested whether the presence of iridescent speckles on the flanks of male X. variata interacted with water turbidity to modify the predatory behavior displayed by the snake T. melanogaster. We predicted that in an experimental laboratory test, the snakes would increase the frequency of their predatory behavior to the extent that the water turbidity decreases. The snakes were tested at six different levels of water turbidity, in combination with three categories of male fish (with few, a median number of, or many speckles). The results showed that in a pool with high or zero turbidity, the number of speckles is not a determining factor in the deployment of the predatory behavior of the snake T. melanogaster toward X. variata. Our findings suggest that snakes can view the fish at intermediate percentages of turbidity, but the number of speckles in male X. variata is irrelevant as an interspecific visual signal in environments with insufficient luminosity. The successful capture of aquatic prey is influenced by integration between chemical and visual signals, according to environmental factors that may influence the recognition of individual traits. © 2015 Manjarrez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source

Buzzetti F.M.,WBA World Biodiversity Association | Barrientos-Lozano L.,Technological Institute of Ciudad Victoria
Bioacoustics | Year: 2011

The songs of the following species are presented: Conocephalus (Xiphidion) cinereus Thunberg, 1815, C. (X.) ictus (Scudder, 1875), C. (X) magdalenae Nascrecki, 2000, C. (Anisoptera) strictus (Scudder, 1875), Dichopetala brevihastata Morse, 1902, D. castanea Rehn & Hebard, 1914, D. pollicifera Rehn & Hebard, 1914, Phyllophyllia guttulata Stå;l, 1863, Stilpnochlora azteca (Saussure, 1859), Boopedon gracile Rehn, 1904, Syrbula montezuma (Saussure, 1861) and Teniopoda tamaulipensis Rehn, 1904. Considerations on distribution, taxonomy, ethology, biodiversity and conservation are given. © 2011 AB Academic Publishers. Source

Rodriguez-Ruiz E.R.,Technological Institute of Ciudad Victoria | Castro-Arellano I.,Texas State University | Valencia-Herverth J.,Autonomous University of the State of Hidalgo
Southwestern Naturalist | Year: 2012

We assessed geographical range of pacas Cuniculus paca in the northern Neotropics based on historical and recent records. We report two new records from Tamaulipas and Hidalgo. These records confirm presence of pacas in this region and support our proposed geographical range along lower elevations of eastern slopes of the Sierra Madre Oriental in Mexico. Source

Presley S.J.,University of Connecticut | Willig M.R.,University of Connecticut | Bloch C.P.,Bridgewater State University | Castro-Arellano I.,University of Connecticut | And 3 more authors.
Biotropica | Year: 2011

The metacommunity framework integrates species-specific responses to environmental gradients to detect emergent patterns of mesoscale organization. Abiotic characteristics (temperature, precipitation) and associated vegetation types change with elevation in a predictable fashion, providing opportunities to decouple effects of environmental gradients per se from those of biogeographical or historical origin. Moreover, expected structure is different if a metacommunity along an elevational gradient is molded by idiosyncratic responses to abiotic variables (expectation=Gleasonian structure) than if such a metacommunity is molded by strong habitat preferences or specializations (expectation=Clementsian structure). We evaluated metacommunity structure for 13 species of gastropod from 15 sites along an elevational transect in the Luquillo Experimental Forest of Puerto Rico. Analyses were conducted separately for the primary axis and for the secondary axis of correspondence extracted via reciprocal averaging. The metacommunity exhibited quasi-Clementsian structure along the primary axis, which represented a gradient of gastropod species specialization that was unassociated with elevation. The secondary axis represented environmental variation associated with elevation. Along this axis, the metacommunity exhibited Clementsian structure, with specialists characterizing each of three suites of sites that corresponded to three distinct forest types. These forest types are associated with low (tabonuco forest), mid- (palo colorado forest), or high (elfin forest) elevations. Thus, variation among sites in species composition reflected two independent processes: the first decoupled from elevational variation and its environmental correlates, and the second highly associated with environmental variation correlated with elevation. © 2010 The Author(s). Journal compilation © 2010 by The Association for Tropical Biology and Conservation. Source

Rodriguez-Flores F.D.J.,Technical University Durango | Nava J.,Technological Institute of Ciudad Victoria
Tropical and Subtropical Agroecosystems | Year: 2016

Aboveground tree biomass (bole, branches and foliage), M, plays a key role in the conventional and sustainable management of forest communities. The standard approach to assess tree or plot M is harvesting trees, developing and fitting allometric equations to trees or forest inventory plot data. In the absence of local tree allometry, it is usually recommended to fit off site allometric equations to evaluate tree or plot M. This research aims: (a) to develop an updated on site allometric equation (b) to fit available off site allometric equations to destructively harvested trees and (c) to fit available allometric equations to plot M of Mexico's Sinaloan tropical dry forests to understand sources of inherent tree and plot M variability. Results showed that: (a) the improved on site allometric equation increases precision in contrast to the conventional biomass equation previously reported as well as to off site tree M equations, (b) off site allometry projects tree and plot M deviates by close to one order of magnitude. Two tested and recommended approaches to increase tree and plot M precision when fitting off site equations are: (i) to use all available tree allometric functions to come up with a mean equation or (ii) to calibrate off site equations by fitting new, local parameters that can be calculated using statistical programs.These options would eventually increase tree and plot M precision in regional evaluations. Source

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