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The plant locally known as ocotillo, Fouquieria splendens (Fouquieriaceae) is a shrub distributed in arid zones of Mexico and southwestern United States. In Mapimi Biosphere Reserve, Durango, it has not leaves for most of the year; these emerge after the first rain. Inflorescences emerge in March, being bright red and lasting only a month. These inflorescences are highly sought after by animals, including insects, birds and the mule deer (Odocoileus hemionus). The objectives of this study were: 1) quantify the inflorescences produced by each plant (during March), 2) estimate inflorescence availability for mule deer, and 3) quantify its contribution in biomass (fresh weight) and nutrient content. This will contribute to understand why deer consume these flowers in the dry season. In March 2012 a field sampling was carried out in the Mapimi Biosphere Reserve, to measure the characteristics of each individual plant, quantify the number of inflorescences produced, the number available for mule deer, and the nutrients they contribute. The nearest-neighbor method was used, measuring 30 ocotillo individuals in nine sites. Inflorescences were collected from different plants to estimate fresh weight and determine nutrient content by proximal chemical analysis. A total of 270 ocotillo plants were sampled. There was a positive correlation between plant diameter and number of both branches and inflorescences. An average of 30 inflorescences was observed, and their availability for deer was 42 % (3,306/7,951) of the total. The average weight of 74 inflorescences collected was 74.8 ± 20.4 g; each plant produced up to 3 kg. These contain high levels of protein (15 % dry basis), carbohydrate (67 %), and 3,085.98 kcal/kg of metabolizable energy; 85 % are digestible nutrients. The mule deer selects plants with high nutritional values that are available in critical seasons such as the dry season. To note, ocotillo flowers emerge when there is food shortage (dry season), and are consumed by deer. A positive correlation was found between number of branches, plant diameter and total number of inflorescences (and its availability). Ocotillo flowers represent an important nutritional resource for deer, because inflorescences have high protein and sugar levels, in addition to having digestible nutrients and that each plant produces around 1.5 kg of inflorescences available for deer in the dry season.

We compiled a list of the herpetofauna of the state of Durango, México, based on published records. The checklist contains 151 species (33 amphibians and 118 reptiles) allocated to one or more of the four major ecoregions of the state. We identified many gaps in the current knowledge of the herpetofauna of Durango, concerning the number of species and their distribution in the state, and hence, further surveys and taxonomic studies are needed to improve the completeness of this checklist.

Estudiamos los ciclos de esteroides sexuales de machos y hembras en estado silvestre de la tortuga del Bolsón en la Reserva de la Biósfera de Mapimí (Durango). Tomamos muestras de sangre por venipunción de la yugular a intervalos bisemanales durante un período de 14 meses, determinándose los niveles circulantes de esteroides por medio de radioinmunoensayos. Los niveles hormonales mostraron tendencias estacionales. En las hembras, la testosterona tuvo un valor máximo al salir de la brumación, en asociación con el incremento en la receptividad sexual, y el nivel de estradiol aumentó después de la emergencia asociado con la maduración folicular. El nivel de estos dos esteroides se incrementó con las lluvias estacionales, cuando ocurrieron el crecimiento folicular y la vitelogénesis. La progesterona mostró niveles bajos a la emergencia, los cuales aumentaron con el incremento de la duración del dia y la temperatura, llegando al máximo antes del pico de la oviposición. La caída en los niveles de las tres hormonas estuvo asociada con la oviposición. Las hembras probablemente almacenan esperma durante parte del otoño y el invierno para usarlo en la siguiente estación reproductiva. Los machos salieron de la hibernación con bajos niveles de testosterona, pero exhibieron conductas reproductivas poco después. Junto con un incremento de la testosterona, el cortejo y la frecuencia de apareamientos se incrementaron con estímulos ambientales, prolongándose hasta principios del otoño. Los niveles de testosterona y la actividad reproductiva disminuyeron conforme se aproximaba el inicio de la hibernación. Los niveles máximos de testosterona en machos de esta especie son mayores que los conocidos para cualquier otro vertebrado.