Propágulos deMangrove species propagules represent a particular survival and dispersal strategy. Unfortunately, some reports have stated that Rhizophora mangle propagules are frequently attacked by Coleoptera and Lepidoptera before and after their dispersion period. The beetle species Coccotrypes rhizophorae is an obligate parasite that can cause mortality in propagules and seedlings of R. mangle, and may modify the structure of its populations. Because of the importance on this mangrove species, survival and increasing human impacts in the area, this study evaluated the presence of propagules with C. rhizophorae boring evidence in the Tumilco mangrove, in Veracruz State, Mexico. For this, three sampling areas were established: 1) mangrove core of R. mangle, 2) most impacted edge of an unpaved road with R. mangle and A. germinans, and 3) edge with Typha latifolia and R. mangle; in each area, three 25x25 m random plots were analyzed. The number of bored propagules per site was recorded every 15 days over a sampling period of one year (n= 567) from January to December 2012. We also observed the damaged part of the propagule (basal, central, apical) and the number of live and dead bored propagules per season, and compared results for different seasons in the area: rainy, cold northerly fronts or "norte" and dry. Insects were identified by an expert. Our results showed that a higher number of bored propagules was observed during the dry season, mainly in zones 2 and 3. Survival of bored propagules was higher when the perforation occurred in the basal part of the plant, and during the dry and norte seasons. Study zone 2 in particular presented a higher number of live propagules when the damage occurred in the basal part of the propagule. In all three zones, mortality was higher when the damage was apical. Zones 1 and 3 presented higher propagule survival during the dry season, while survival in zone 2 was higher during the rainy and norte seasons. The number of propagules decreased with rising flooding levels. The results showed that C. rhizophorae has a wide distribution in the Tumilco mangrove, but the mortality of R. mangle propagules is influenced by the part of the propagule that suffers damage, as well as by the season of the year and the characteristics of the area in which the infestation occurs. Futher studies are required to evaluate the impact of propagule mortality on the population structure of R. mangle. Rev. Biol. Trop. 65 (3): 1120-1128. Epub 2017 September 01.

Se identificó el límite superior de bosque continuo y discontinuo en las montañas superiores a 4000 metros sobre el nivel del mar en México. El estudio se basó en el índice de vegetación de diferencia normalizada y mediante el análisis de componentes principales. Para el primer caso, se encontró que en cada vertiente el límite de bosque alcanza una altitud distinta; sin embargo, en promedio el bosque continuo culmina a 4019 y el discontinuo a 4072 msnm. Por su parte, el análisis estadístico permitió determinar que la precipitación, el tipo de suelo y la tasa de radiación solar a nivel de superficie son los principales factores que rigen su altitud. Finalmente se halló que el régimen de temperatura encontrado en esta frontera se aproxima a los valores estándares de la zona intertropical.

ResumenSe analizó la composición de especies y se evaluó la eficiencia en la remoción de estiércol vacuno por escarabajos del estiércol de la subfamilia Scarabaeinae durante las temporadas de lluvias y secas en 2 zonas ganaderas del norte de Veracruz con diferente cobertura vegetal. Tamiahua, con pastizales sin vegetación arbórea, solo con árboles aislados y Tlacolula, con vegetación arbórea en los alrededores de los pastizales y cercas vivas. Se recolectaron 5 especies en Tamiahua y 16 en Tlacolula. Las especies más abundantes en Tamiahua fueron: Canthidium pseudopuncticolle (Harold, 1867), Canthon cyanellus cyanellus LeConte y Digitonthophagus gazella Fabricius, mientras que en Tlacolula fueron: C. c. cyanellus, Coprophanaeus pluto Harold y C. pseudopuncticolle. En la temporada de lluvias, la remoción del estiércol fue mayor en los pastizales de Tlacolula que en los de Tamiahua; sin embargo, en ambas localidades no hubo remoción de estiércol en la temporada de secas. En ambas zonas, la especie dominante en el proceso de remoción de estiércol fue D. gazella, especie africana introducida. Nuestros resultados sugieren que la reincorporación del estiércol se ve afectada por la composición de especies, la temporada del año y por la heterogeneidad del paisaje en las zonas ganaderas del norte de Veracruz.

Phytochemical composition, antioxidant, and toxic effects of two orchid (Prosthechea cochleata and Prosthechea livida) were examined in their different hexane and dichloromethane/methanol extracts of leaves, pseudobulbs, rhizome and roots.  Phytochemical screening reveals the presence of alkaloids, coumarins, flavonoids, saponins, steroids and terpenes except for anthracene derivatives in P. livida and tannins in both species. Results showed exhibited significant toxicity against brine shrimp with an LC50 values ranged from 3 to 54 µg/ml in 24 h.  Finally, the results of the antioxidant test in yeast (Saccharomyces cerevisiae) showed that CH2Cl2:MeOH extract of P. cochleata root extract presented the most efficient protective antioxidant percentage (%PA), with 20 µg/mL, displaying a cell viability of 68.58%. In P. livida case, rhizome extract presented the most efficient %PA, with 1000 µg/mL, with a cell viability of 65.82%.  The results evidenced the toxicity of  Prosthechea cochleata and Prosthechea livida and reveals potential antioxidative of extracts.

Stanhopea is an orchid’s genus that includes 55 species distributed from Mexico to Argentina. However, due to its horticultural potential, a decrease in wild populations has been generated by the effect of over-collecting, further aggravated by the effect of habitat destruction, placing some species of Stanhopea from Mexico in some risk categories. In this work, the potential distribution areas of six endemic Stanhopea species in Mexico and in some Federal Natural Protected Area (ANP) were modeled with the use of the MaxEnt software. The potential distribution of the six endemic species in Mexico was obtained, in addition to the fact that it is possible to find one or more species within 74 ANPs.