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The moth Rothschildia lebeau uses three tree species as its primary larval hosts in the tropical dry forest of northwestern Costa Rica. These hosts were shown previously to have different relative effects on caterpillar performance, resulting in an apparent host-related life history trade-off between large adult body size on the one hand but low offspring survival on the other. To further assess the potential ecological and evolutionary importance of this trade-off, an observational field study of the relationship between male body size and mating success was conducted. Across mating trials, larger males had a higher probability of being observed mating. Independent of the effect of size, the amount of wing damage an individual had sustained (a measure of relative age) was negatively correlated with the probability a male was observed mating. Within mating trials, the mated male tended to be larger than the average unmated male, but there was no difference in wing damage. Overall, results of this study were consistent with a positive effect of male body size on mating success, consistent with the idea that larval host plant history and its effects on adult body size matters in terms of adult male fitness. However, all sized males were observed mating over the course of the study, and the size advantage did not appear to be particularly strong. RESUMEN La mariposa nocturna Rothschildia lebeau utiliza tres especies de arboles como las plantas hospederas mas importantes en el bosque seco tropical del noroeste de Costa Rica. Se habia demostrado anteriormente que estas tres plantas hospederas tienen efectos distintos relativos al desarrollo de las larvas; aparentemente, el tipo de arbol hospedero juega un papel significativamente influyente en el equilibrio entre una talla mayor del adulto y una menor supervivencia de las larvas. Para investigar mas la importancia ecologica y evolucionaria de este intercambio de ventajas y desventajas un estudio observacional de campo de la relacion entre el tamano del cuerpo de mariposas machos y el exito que tenian en parearse fue llevado a cabo. En todas las observaciones, los machos mas grandes tenian una probabilidad mas elevada de aparearse. Independientemente del efecto del tamano del cuerpo, la cantidad de danos que cada macho habia sostenido en las alas (una aproximacion de edad relativa) fue correlacionada negativamente con la probabilidad que el macho fuera observado apareandose. Individualmente, el macho que tenia exito en parearse tenia la tendencia a ser mas grande que los individuos que no tenian exito, pero no habia ninguna diferencia entre ellos en la cantidad de danos que habian sufrido en sus alas. En general los resultados de este estudio son consistentes con un efecto positivo del tamano del cuerpo del macho sobre su exito de apareamiento, lo que apoya la idea de que el efecto de la planta hospedera sobre el tamano de la larva es importante y contribuye a un mejor ajuste de nicho por parte de los machos adultos. Sin embargo, los machos de todo tamano fueron observados apareandose sobre el transcurso del estudio, y la ventaja conferida por el tamano no pareciera a ser muy fuerte.

Tropical dry forests are located predominantly in the northern portion of Venezuela, above 6°N. Although their potential extent covers ca 400,000 km2 (44% of the land), they currently occupy about 10 percent of this area. The diversity and complexity of Venezuelan dry forests increases from north to south along a gradient of decreasing severity of the dry season. A typical dry forest in Venezuela presents ca 110–170 species of plants from ca 40 to 50 families within an area of approximately 10 ha. Species composition and forest structure, however, are dependent on local landscape conditions (e.g., soil type, topography), and nearby forest types can be very different. Our analysis of five dry forest variants showed a maximum family similarity of 67 percent, although most values fell in the 50–60 percent interval. They are currently considered as one of Venezuela's most threatened ecosystems, but only 5 percent of extant dry forests are included in protected areas; this represents 0.5 percent of their potential extent. It is fundamental to promote the creation of at least 3 or 4 more large protected areas (ca 5000 ha), with different climatic and orographic characteristics, in combination with the recovery of threatened species, the restoration of degraded systems, and the implementation of sustainable development projects. Their apparent high resilience suggests that with the proper management we can restore and maintain the integrity of Venezuelan dry forests. RESUMEN Los bosques secos tropicales de Venezuela se ubican predominantemente al norte del pais, por encima de los 6°N. Aunque su distribucion potencial abarca ca 400,000 km2 (44 porciento del territorio terrestre), actualmente ocupan 10 porciento de esta area. La diversidad y complejidad de bosques secos en Venezuela aumenta de norte al sur, la direccion en la que el numero de meses secos disminuye de 8 a 3. Un bosque seco tipico en Venezuela presenta ca 110–170 especies de plantas, de ca 40–50 familias. La composicion de especies y la estructura de los bosques, sin embargo, son dependientes de las condiciones locales del terreno (e.g., tipo de suelo, topografia), por lo que tipos de bosque cercanos pueden ser muy diferentes. Nuestro analisis de cinco variantes revelo una similaridad entre familias de 67 porciento, aunque la mayoria de los valores cayo entre 50 y 60 porciento. Actualmente son considerados como uno de los ecosistemas venezolanos mas amenazadas, pero solo 5 porciento de los bosques secos remanentes estan incluidos en areas protegidas; esto representa 0.5 porciento de su distribucion potencial. Es fundamental promover la creacion de al menos 3 o 4 areas protegidas grandes adicionales (ca 5000 ha), con condiciones climaticas y orograficas diferentes, en combinacion con la recuperacion de especies amenazadas, la restauracion de sistemas degradados y la implementacion de proyectos de desarrollo sostenible. Su alta resiliencia aparente sugiere que con el manejo adecuado se podria restaurar y mantener la integridad de los bosques secos de Venezuela.

We integrate forest structure and remotely sensed data for four successional stages (pasture, early, intermediate, and late) of a tropical dry forest area located in the Sector Santa Rosa of the Guanacaste Conservation Area in northwestern Costa Rica. We used a combination of spectral vegetation indices derived from Landsat 7 ETM+ medium resolution and IKONOS high-resolution imagery. The indices (using the red and near-infrared bands) simple ratio and normalized difference vegetation index separated the successional stages well. Two other indices using mid-infrared bands did not separate successional stages as well. In a comparison of the successional stages with chronological age, there was no separability in the spectral reflectance among different age classes. Successional stages, in contrast, showed distinct groups with minimal overlap. We also applied a simple validation in another dry forest located in the Palo Verde National Park in the province of Guanacaste, Costa Rica, with reasonably good results. RESUMEN En este estudio, datos de campo y datos remotamente sensados son analizados para cuatro etapas sucesionales (pastos, temprano, intermedio y tardio) de un bosque seco tropical ubicado en el sector Santa Rosa del Area de Conservacion Guanacaste en el noroeste de Costa Rica. Utilizamos una combinacion de indices spectrales derivados imagenes satelitales, de mediana resolucion de Landsat 7 ETM+ y de alta resolucion de IKONOS. Los indices (usando las bandas de rojo e infrarojo cercano) de relacion simple (SR) e indice normalizado de diferencia vegetal (NDVI) separo bien las etapas sucesionales. Asi otros dos indices, usando las bandas de infrarojo medio no separaron las etapas sucesionales. En una comparacion de las etapas sucesionales con la edad cronologica, no existio separabilidad en la reflectancia espectral entre las diferentes clases de edad. Sin embargo, las etapas sucesionales mostraron grupos distinguibles con minima sobreposicion.Tambien aplicamos una simple validacion en otro bosque seco ubicado en el Parque Nacional Palo Verde en la provincia de Guanacaste, Costa Rica.

In 1998, we measured the effects of Hurricane Georges after it passed over long-term research sites in Puerto Rican dry forest. Our primary objectives were to quantify hurricane effects on forest structure, to compare effects in a large tract of forest versus a series of nearby forest fragments, to evaluate short-term response to hurricane disturbance in terms of mortality and sprouting, and to assess the ability of hurricanes to maintain forest structure. We sampled damage from 33 plots (1.3 ha) across a 3000-ha tract of forest as well as in 19 fragments. For stems with 2.5-cm minimum diameter, 1004 stems/ha (12.4%) suffered structural damage, while 69 percent of the undamaged stems were at least 50 percent defoliated. Basal area lost to structural damage equaled 4.0 m2/ha (22%) in south-facing native forests. Structural damage and defoliation increased with stem diameter and were more common in certain dry forest species. South-facing forests and those on ridgetops incurred more damage than north-facing forests or those comprised primarily of introduced species. Stem mortality was only 2 percent of all stems after 9 mo. Structural damage did not necessarily result in stem mortality. Hurricane-induced mortality was not associated with stem height or diameter, but was ten times greater than background mortality. Basal sprouting was proportional to the amount of structural damage incurred in a stand. Forest fragments experienced the same patterns of hurricane effects as the reference forest. The low, dense structure of Caribbean dry forest can be maintained by hurricane damage to larger stems and induction of basal sprouting to generate multistemmed trees. RESUMEN En 1998 medimos los efectos del Huracan George despues de que paso por sitios localizados en Puerto Rico y dedicados a la investigacion a largo plazo. Nuestros objetivos fueron cuantificar los efectos de huracanes en la estructura del bosque y comparar estos efectos en un bosque especifico con una serie de fragmentos de bosque que se encontraban en la proximidad a nuestra area de estudio. La evaluacion de la respuesta rapida del bosque seco debido a los efectos de huracanes se exploro en terminos de la mortalidad y regeneracion, asi como se estudio la habilidad de los huracanes de mantener la estructura del bosque. Para este estudio de muestreo, 33 parcelas con danos (1.3 ha) a lo largo de una seccion de 3000 ha de bosque asi como en 19 fragmentos de bosque. En tallos con ≥2.5 cm de diametro, 1004 tallos/ha (12.4%) sufrieron dano estructural, mientras que el 69 porciento de los tallos no danados fueron al menos en un 50 por ciento defoliadas. Perdidas en area basal debido al dano estructural fue equivalente a 4.0 m2/ha (22%). Bosques con pendientes en direccion sur y aquellos en los topes de las colinas presentaron mas danos que bosques con pendientes orientadas hacia el norte o aquellos que estaban constituidos principalmente de especies introducidas. Mortalidad en los tallos fue solamente un 2 porciento despues de 9 meses, asi como tambien se encontro que el dano estructural no contribuyo a la mortalidad de tallos. Mortalidad inducida por el huracan no se encontro asociada con el diametro o altura de los tallos o bien su diametro, pero fue 10 veces mas grande que la mortalidad de control. Los fragmentos de bosques experimentaron el mismo comportamiento que el bosque de referencia.

The phenology of 19 species of plants was followed for two years at Serra Talhada, Pernambuco State, Northeastern Brazil. Ten plants of each species were monitored biweekly. All plants had a complete canopy cover from February (well established rainy season) until May-June (just after rains ceased), and all but a few individuals, belonging to six species, were leafless in October-November (peak of the dry season). Leaf fall and flush, flowering, and fruiting were almost continuous in the community throughout both the years, but they peaked at different periods. The peak of leaf flush preceded the rainy season, spurred by occasional rains, followed by flowering early in the rainy season, and then fruiting. Leaf fall became more pronounced after the rainy season. The species covered a whole range of deciduousness, from those which retained their leaves throughout both years to those which were leafless during 6–7 months each year. This was mostly due to the capacity of leaf retention after the onset of the dry season. Autochoric and zoochoric species produced fruits mostly during the rainy season and anemochoric species during the dry period. The patterns of flowering and fruiting were complex. One species did not produce flowers or fruits in either year; five produced flowers and fruits in one year only and two others produced flowers in both years but fruits in only one. Most of the other species had high intraspecific synchrony and produced flowers for a shorter period than fruits. RESUMEN A fenologia de 19 especies de plantas foi acompanhada por dois anos, em Serra Talhada, PE. Dez plantas de cada especie foram observadas a intervalos de duas semanas. Todas as plantas tinham a copa completa de fevereiro (estacao chuvosa bem estabelecida) a maio—junho (logo apos o termino das chuvas) e todas, com excecao de poucos individuos pertencentes a seis especies, estavam sem foihas em outubro–novembro (auge da estacao seca). Queda e formacao de folhas novas, floracao e frutificacao foram quase continuas na comunidade, durante 0s dois anos, mas com picos em periodos diferentes. 0 pic0 de formacao de folhas precedeu a estacao chuvosa, impulsionado por chuvas esporadicas, seguido do de floracao, no inicio da estacao de chuvas, e depois pelo de frutificacao. Queda de folhas foi mais pronunciada depois do periodo chuvoso. As especies cobriram toda ma gama de caducifolia, desde as que mantiveram as folhas durante 0s dois anos as que ficaram defoliadas durante 6–7 meses cada ano. Isto deveuse, principalmente, as suas capacidades de reter folhas ao longo da estacao sea. Especies autooricas e zoocoricas produziram frutos principalmente no periodo chuvoso e as especies anemocoricas no periodo seco. Os padroes de floracao e frutificacao foram complexos. Uma especie nao produziu flores ou frutos nos dois anos, cinco produziram flores e frutos apenas em um dos anos e duas outras, em urn dos anos, produziram flores que nao se desenvolveram em frutos. A maioria das outras especies teve alta sincronia intra-especifica e produziu flores por urn periodo mais curto que frutos.