Diet of Crotalus enyo (Serpentes: viperidae) from the Baja California Cape Region, Mexico

Crotalus enyo is a rattlesnake endemic to Baja California peninsula, Mexico. The natural history of this species is poorly known, so the goal of this study was to determine the diet of C. enyo in the Cape Region, an area with different conditions than the rest of the peninsula. We analyzed the stomach contents of 24 specimens obtained during 2010-2013, and identified the ingested prey. The diet of C. enyo consists of rodents (83.34%) and lizards (16.66%), although presents a diverse diet, the data suggest C. enyo is a specialist predator at Cape Region. We didn’t find differences in diet composition between sexes, site of capture, or season. This study documents three new prey items in the diet of C. enyo: the Orange-Throated Whiptail (Aspidocelis hyperythra), the Cape Spiny-Tailed Iguana (Ctenosaura hemilopha) and Hunsaker’s Spiny Lizard (Sceloporus hunsakerii).Crotalus enyo is a rattlesnake endemic to Baja California peninsula, Mexico. The natural history of this species is poorly known, so the goal of this study was to determine the diet of C. enyo in the Cape Region, an area with different conditions than the rest of the peninsula. We analyzed the stomach contents of 24 specimens obtained during 2010-2013, and identified the ingested prey. The diet of C. enyo consists of rodents (83.34%) and lizards (16.66%), although presents a diverse diet, the data suggest C. enyo is a specialist predator at Cape Region. We didn’t find differences in diet composition between sexes, site of capture, or season. This study documents three new prey items in the diet of C. enyo: the Orange-Throated Whiptail (Aspidocelis hyperythra), the Cape Spiny-Tailed Iguana (Ctenosaura hemilopha) and Hunsaker’s Spiny Lizard (Sceloporus hunsakerii)

Diet of Crotalus enyo (Serpentes: viperidae) from the Baja California Cape Region, Mexico

Crotalus enyo is a rattlesnake endemic to Baja California peninsula, Mexico. The natural history of this species is poorly known, so the goal of this study was to determine the diet of C. enyo in the Cape Region, an area with different conditions than the rest of the peninsula. We analyzed the stomach contents of 24 specimens obtained during 2010-2013, and identified the ingested prey. The diet of C. enyo consists of rodents (83.34%) and lizards (16.66%), although presents a diverse diet, the data suggest C. enyo is a specialist predator at Cape Region. We didn’t find differences in diet composition between sexes, site of capture, or season. This study documents three new prey items in the diet of C. enyo: the Orange-Throated Whiptail (Aspidocelis hyperythra), the Cape Spiny-Tailed Iguana (Ctenosaura hemilopha) and Hunsaker’s Spiny Lizard (Sceloporus hunsakerii)

JUVENILE RECRUITMENT, EARLY GROWTH, AND MORPHOLOGICAL VARIATION IN THE ENDANGERED SANTA CATALINA ISLAND RATTLESNAKE, CROTALUS CATALINENSIS

Life-history information constitutes the raw data for building population models used in species conservation. We provide life-history data for the endangered Santa Catalina Island Rattlesnake, Crotalus catalinensis. We use data from 277 observations of C. catalinensis made between 2002 and 2011 on the island. Mean snout-vent length (SVL) of adult C. catalinensis was 643 mm for males and 631 mm for females; the difference was not significant. The degree of sexual size dimorphism (SSD; using SVL) was -0.02. However, sexes were dimorphic in total length ( SVL + tail length), relative tail length, and stoutness. Juvenile recruitment occurs during late-summer. In their first year of life, juveniles seem to grow at a rate of about 1.7 cm/mo. Females seem to become mature around 570 mm SVL, probably in the year when they become 2 y old. Scattered literature data corroborates the time of juvenile recruitment described herein. Growth in C. catalinensis seems to be slower than that of C. ruber, its sister taxa, but similar to other rattlesnakes.Comision Nacional para el Conocimiento y Uso de la Biodiversidad (CONABIO)Comision Nacional para el Conocimiento y Uso de la Biodiversidad (CONABIO)Secretaria del Medio Ambiente y Recursos Naturales (SEMARNAT)Secretaria del Medio Ambiente y Recursos Naturales (SEMARNAT)Consejo Nacional de Ciencia y Tecnologia (CONACyT) [FB1484/HK051, SEMARNAT-CONACyT-2002-C01-0584]Consejo Nacional de Ciencia y Tecnologia (CONACYT)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2010/50146-3]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP

Vaccination strategy on a geographic network

We considered a mathematical model describing the propagation of an epidemic on a geographical network. The initial growth rate of the disease is the maximal eigenvalue of the epidemic matrix formed by the susceptibles and the graph Laplacian representing the mobility. We use matrix perturbation theory to analyze the epidemic matrix and define a vaccination strategy, assuming the vaccination reduces the susceptibles. When the mobility is small compared to the local disease dynamics, it is best to vaccinate the vertex of least degree and not vaccinate neighboring vertices. Then the epidemic grows on the vertex corresponding to the largest eigenvalue. When the mobility is comparable to the local disease dynamics, the most efficient strategy is to vaccinate the whole network because the disease grows uniformly. However, if only a few vertices can be vaccinated then which ones do we choose? We answer this question, and show that it is most efficient to vaccinate along the eigenvector corresponding to the largest eigenvalue of the Laplacian. We illustrate these general results on a 7 vertex graph, a grid, and a realistic example of the french rail network

Impacto de la erradicación del gato (felis catus), en dos roedores endémicos de la Isla Coronados, Golfo de California, México

It is not known when the domestic cat (Felis catus) was introduced to Coronados Island or when they reached it. Their impact on endemic rodents has been evident, rodents constitute 70% of their diet and they are putting in danger the survival of rodents. Cat eradication was initiated in November 1998 and finished in March 1999. In order to identify the eventual response of rodents to the absence of cats, a monitoring program of two resident rodents Peromyscus pseudocrinitus and Chaetodipus spinatus pullus, was undertaken before, during, and after the eradication program. The monitoring program finished in 2005. Initially an increase in rodent populations occurred followed by fluctuations in the population. Despite the fact that there was no evident benefit derived from the eradication program, it is clear that their removal was positive, since their presence represented a potential risk to endemic rodent species on the island, which could be exterminated during critical periods if feral cat continued in the island.Se desconoce el año en que fue introducido el gato (Felis catus) a la Isla Coronados, así como el número máximo que alcanzó su población, sin embargo, su efecto sobre los roedores nativos fue evidente, ya que los integró a su dieta, constituyendo el 70% de la misma, poniendo en peligro su supervivencia. El programa de erradicación de gatos fue iniciado en noviembre de 1998 hasta la remoción de todos los individuos en marzo del 1999. Se llevó a cabo el monitoreo de las poblaciones de Peromyscus pseudocrinitus y Chaetodipus spinatus pullus antes, durante y después del programa de erradicación, concluyendo el monitoreo en el año 2005, con el fin de identificar la eventual respuesta de los roedores a la ausencia de gatos. A corto plazo se presentó un incremento en las poblaciones de roedores, sin embargo, a largo plazo, estas fluctuaron de acuerdo a la disponibilidad de alimento y a las condiciones climáticas prevalecientes. A pesar de que no hubo evidencia numérica en las poblaciones de roedores, del beneficio de la erradicación de gatos, es claro que su remoción fue positiva, ya que su presencia representaba un riesgo potencial para las especies presentes, las cuales podrían ser extinguidas durante períodos críticos si los gatos continuaran presentes en la isla

Impacto de la erradicación del gato (felis catus), en dos roedores endémicos de la Isla Coronados, Golfo de California, México

It is not known when the domestic cat (Felis catus) was introduced to Coronados Island or when they reached it. Their impact on endemic rodents has been evident, rodents constitute 70% of their diet and they are putting in danger the survival of rodents. Cat eradication was initiated in November 1998 and finished in March 1999. In order to identify the eventual response of rodents to the absence of cats, a monitoring program of two resident rodents Peromyscus pseudocrinitus and Chaetodipus spinatus pullus, was undertaken before, during, and after the eradication program. The monitoring program finished in 2005. Initially an increase in rodent populations occurred followed by fluctuations in the population. Despite the fact that there was no evident benefit derived from the eradication program, it is clear that their removal was positive, since their presence represented a potential risk to endemic rodent species on the island, which could be exterminated during critical periods if feral cat continued in the island.Se desconoce el año en que fue introducido el gato (Felis catus) a la Isla Coronados, así como el número máximo que alcanzó su población, sin embargo, su efecto sobre los roedores nativos fue evidente, ya que los integró a su dieta, constituyendo el 70% de la misma, poniendo en peligro su supervivencia. El programa de erradicación de gatos fue iniciado en noviembre de 1998 hasta la remoción de todos los individuos en marzo del 1999. Se llevó a cabo el monitoreo de las poblaciones de Peromyscus pseudocrinitus y Chaetodipus spinatus pullus antes, durante y después del programa de erradicación, concluyendo el monitoreo en el año 2005, con el fin de identificar la eventual respuesta de los roedores a la ausencia de gatos. A corto plazo se presentó un incremento en las poblaciones de roedores, sin embargo, a largo plazo, estas fluctuaron de acuerdo a la disponibilidad de alimento y a las condiciones climáticas prevalecientes. A pesar de que no hubo evidencia numérica en las poblaciones de roedores, del beneficio de la erradicación de gatos, es claro que su remoción fue positiva, ya que su presencia representaba un riesgo potencial para las especies presentes, las cuales podrían ser extinguidas durante períodos críticos si los gatos continuaran presentes en la isla

Dieta y ámbito hogareño del gato feral, Felis catus (Carnivora: Felidae) en la Isla Socorro, Archipiélago de Revillagigedo, México

Socorro is an oceanic island rich in biodiversity and endemisms. However, the island has been threatened by feral cats since 1957. The diet of this predator, determined through the analysis of stomach contents of 79 cats, consisted mostly of house mice (Mus musculus, 22.16%), endemic lizards (Urosaurus auriculatus, 15.09%), anthropogenic rubbish (15.09%), and insects (Orthoptera, 13.20%). The home range of the feral cat was identified through telemetry using four individuals with GPS/VHF radio-collars. The three males had a much larger average home range of 219.10 ha, as compared with 118.86 ha of the female. Knowing the home range of the Socorro Island feral cat is critical for the successful eradication of the island's invasive population. Thanks to this information, it is possible to calculate the trapping effort and the amount of bait needed per unit area to successfully carry out the ongoing eradication, contributing to the conservation of global biodiversity.Isla Socorro es una isla oceánica rica en biodiversidad y endemismos. Sin embargo, la isla ha sido impactada por el gato asilvestrado desde 1957. A través del análisis del contenido estomacal de 79 gatos se determinó la dieta de este depredador, la cual está constituida mayormente por el ratón doméstico (Mus musculus, 22.16%), la lagartija endémica (Urosaurus auriculatus, 15.09%), residuos antropogénicos (15.09%), e insectos (Orthoptera, 13.20%). Se identificó el ámbito hogareño de los gatos a través de telemetría, utilizando cuatro individuos con radio-collares GPS/VHF. El ámbito hogareño de los machos resultó de 219.10 ha en promedio, mucho mayor que el de las hembras que fue de 118.86 ha. Conocer el ámbito hogareño del gato asilvestrado de Isla Socorro es clave para la erradicación exitosa de la población de la isla. Gracias a esta información se ha podido calcular el esfuerzo de trampeo o la cantidad de carnada que deben ser empleadas por unidad de área durante la erradicación en curso, que es relevante para la conservación de la biodiversidad global