Abstract. During the past 12 000 years agricultural systems have transitioned from natural habitats to conventional agricultural regions and recently to large areas of genetically engineered (GE) croplands. This GE revolution occurred for cotton in a span of slightly more than a decade during which a switch occurred in major cotton production areas from growing 100% conventional cotton to an environment in which 95% transgenics are grown. Ecological interactions between GE targeted insects and other insectivorous insects have been investigated. However, the relationships between ecological functions (such as herbivory and ecosystem transport) and agronomic benefits of avian or mammalian insectivores in the transgenic environment generally remain unclear, although the importance of some agricultural pest management services provided by insectivorous species such as the Brazilian free-tailed bat, Tadarida brasiliensis, have been recognized.We developed a dynamic model to predict regional-scale ecological functions in agricultural food webs by using the indicators of insect pest herbivory measured by cotton boll damage and insect emigration from cotton. In the south-central Texas Winter Garden agricultural region we find that the process of insectivory by bats has a considerable impact on both the ecology and valuation of harvest in Bacillus thuringiensis (Bt) transgenic and nontransgenic cotton crops. Predation on agricultural pests by insectivorous bats may enhance the economic value of agricultural systems by reducing the frequency of required spraying and delaying the ultimate need for new pesticides. In the Winter Garden region, the presence of large numbers of insectivorous bats yields a regional summer dispersion of adult pest insects from Bt cotton that is considerably reduced from the moth emigration when bats are absent in either transgenic or non-transgenic crops. This regional decrease of pest numbers impacts insect herbivory on a transcontinental scale. With a few exceptions, we find that the agronomics of both Bt and conventional cotton production is more profitable when large numbers of insectivorous bats are present.

. 2009. Análisis ecoló-gico básico de los gastrópodos terrestres de la Región Oriental de San Luis Potosí, México. Acta Zool. Mex. (n. s.) 25(1):105-122. RESUMEN. En este estudio se caracterizaron las condiciones ecológicas en las que se presentaron 77 especies de gastrópodos terrestres en la región oriental de San Luis Potosí, existiendo más especies de moluscos en bosque de encino (44 especies), hojarasca y humus (66), suelos húmedos todo el año (53), precipitaciones de 3000-3500 mm anuales (41) y altitudes de 801-900 m (43). Thysanophora hornii es la de mas amplia distribución en función de los tipos de vegetación, condiciones de humedad, precipitación, tipos de suelo y rango de altitud. Los valores más grandes de diversidad y equitatividad se observaron en el bosque mesófilo de montaña (0.6895) y bosque de encino (0.3512). El mayor valor de dominancia (0.9958) y amplitud ecológica del hábitat (0.3471) se presentó en el matorral xerófilo. Las comunidades de gastrópodos terrestres se encontraron subordinadas ecológicamente a las del bosque tropical caducifolio -subcaducifolio, y a su vez ésta se halla subordinada a la del bosque de encino. El valor de similitud cualitativa más alto se observó entre el bosque tropical caducifolio-subcaducifolio y pastizal-cultivos (0.7462). Entre el bosque espinoso y pastizalcultivos se obtuvo el mayor valor de similitud cuantitativa (0.3646). Palabras clave: Gastropoda terrestres, biodiversidad, San Luis Potosí, región oriental, ecología. ABSTRACT. Of 77 species of terrestrial gastropods found in the eastern region of the state of San Luis Potosí, the ecological conditions supporting the largest number of species of mollusks are as follows: oak forest (44 species), leaf litter and humus (66), soils which are humid throughout the year (53), 3000-3500 mm annual rainfall (41) and 801-900 m altitude (43). Thysanophora hornii exhibits the greatest distribution with regard to vegetational types, humidity conditions, rainfall, soil types, and altitudinal ranges. The greatest values of diversity and evenness were obtained in the cloud forest (0.6895) and oak forest (0.3512) respectively. The chaparral exhibits the greatest dominance (0.9958) and habitat ecological width (0.3741). Mollusks communities were ecologically ranked lower than the tropical decidouos-subdeciduous forest. The highest qualitative similarity was observed between tropical deciduous-subdeciduous forest and savannah-cultivation (0.7462). The greatest quantitative similarity (0.3646) was observed between thorn forest and savannah-cultivation. Correa

Use of time as mediator of ecological interactions is important but has been poorly studied and has received less attention than other niche axes. We characterized and compared patterns of activity, and temporal activity overlap of a bat assemblage at a riparian forest from La Peregrina Canyon, Tamaulipas, Mexico. Bats were captured during twenty one-nights, distributed over a year, using mistnets. Nets were opened before sunset and closed 13 h later, being checked every 30 min. A total of 22 species were recorded, with Sturnira lilium, Desmodus rotundus, S. ludovici, Artibeus lituratus and Pteronotus davyi, as the most abundant species. The activity of D. rotundus was different from other abundant species, except with A. lituratus with whom had a high activity overlap. Within the assemblage, the highest temporal overlap was between S. lilium and S. ludovici. Among common guilds, frugivores showed a different pattern from that of insectivores and sanguinivores. Although riparian zones mainly provide roost, food and water, they also provide protection along streams, therefore are used as a flight corridor. This is the first study that analyzes temporal use by neotropical bats of a riparian habitat using null model analysis with different time resolutions. key words: activity patterns, chiroptera, chronoecology, community structure, La Peregrina Canyon, Mexico, null models. La repartición del nicho temporal puede ser un mecanismo viable para la coexistencia de las espe- cies, pero ha sido pobremente estudiado y recibido menor atención que otros ejes (i.e. alimento y espacio). En este estudio caracterizamos y comparamos patrones de actividad y sobrelapamiento de actividad temporal en un ensamblaje de murciélagos del bosque ripario en el cañón de La Peregrina, Tamaulipas, México. Se capturaron murciélagos durante veintiuna noches utilizando redes de niebla. Las redes se abrieron antes de la puesta del sol, se cerraron 13 hr después, y se revisaron cada 30 min. Se registraron un total de 22 especies, con Sturnira lilium, Desmodus rotundus, S. ludovici, Artibeus lituratus y Pteronotus davyi, como las especies más abundantes. La actividad de D. rotundus fue diferente a la del resto de especies abundantes, con excepción de A. lituratus con quién presento el mayor sobrelapamiento de actividad. Dentro del ensamblaje, el más alto sobrelapamiento temporal fue entre S. lilium y S. ludovici. A través de gremios tróficos, los frugívoros mostraron un patrón diferente al de insectívoros y sanguinívoros. Aunque las zonas riparias proporcionan principalmente refugio, alimento y agua, también brindan protección a lo largo de arroyos, por lo tanto son utilizadas como un corredor de desplazamiento. Este es el primer estudio que analiza el uso temporal por murciélagos neotropicales de un hábitat ripario utilizado análisis de modelo nulo con diferentes resoluciones de tiempo. palabras clave: patrones de actividad, Chiroptera, cronoecología, estructura de comunidades, Cañón La Peregrina, México, modelos nulos.

Abstract.-This study provides both a current taxonomic listing of known species of marine bivalves from the co ast of Tamaulipas, Mexico as well as an overall assessment of their poorly known biogeographical relationships. Marine bivalves were surveyed (midlittoral, supralitoral and sublittoral zones) from September 1987 to April 2010. One hundred and thirtyone species of marine bivalves representing 98 genera in 37 families are reported. Two species are f irst records for Tamauli pas. These 131 species share the fol lowing malacogeographical relationshi ps: 62 speci es (47.3 2%) exhibit Caribbean and Carolinian affinities, 20 species (15.26%) exhibit Carolinian and Caribbean affinities, 13 species (9.92%) exhibit Carolinian and Argentinean affinities and 12 species (9.16%) exhibit Caribbean, Carolinian a nd Boreal affinities. Only 6 species (4.58%) exhibit an exclusive Caribbean distribution and 4 species (3.05%) are known only from the Gulf of Mexico. The fact that 81.66% (107 species) of the marine Tamaulipan bivalve fauna exhibits the above malacogeographical relationships provides overwhelming evidence that the Tamaulipan coast of Mexico represents a transitional zone between the Carolinian and Caribbean malacological provinces. Key words: Mollusks, biogeography, Caribbean and Carolinian provincesResumen.-La biogeografía de los bivalvos marinos mexicanos es pobremente conocida, aunque varios estudios se han realizado pero con un enfoque taxonómico. Este estudio contribuye con nueva información sobre la distribución geográfica de los bivalvos marinos de la costa del estado de Tamaulipas. Entre septiembre de 1987 y abril de 2010 se estudiaron los bivalvos marinos (zonas mesolitoral, supralitoral y sublitorial) del área de estudio. Se registran 131 especies incluidas en 98 géneros y 37 familias. Dos especies son primeros registros para el estado. Las principales afinidades malacogeográficas son la principalmente Caribeña y Caroliniana (62 especies: 47,32%), Caroliniana y Caribeña (20 especies: 15,26%), principalmente Caribeña, Caroliniana y Argentiniana (13 especies: 9,92%) y la principalmente Caribeñ a, Caroliniana y Boreal con 12 especies (9,16%) que juntas suman el 81,66% del total de las especies (107 especies), lo que prueba que la costa tamaulipeca es una zona de transición de las provincias malacológicas Caroliniana y Caribeña. Sólo 6 especies (4,58%) poseen una afinidad exclusivamente Caribeña. Cuatro especies (3,05%) restringen su ámbito geográfico conocido al Golfo de México.

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