The beetle genus
has evolved in association with tropical ginger plants and for many species their specific host plant associations are known. Here we show that the core microbiome of six closely ...related Costa Rican
species comprises only eight bacterial groups, including members of the
, Enterobacteriacea,
,
and
. The
and Enterobacteriacea together accounted for 35% of the total average 16S rRNA ribotypes recovered from all specimens. Further, microbiome diversity and community structure was significantly linked to beetle diet breadth, between those foraging on less than two plant types (specialists) versus over nine plant types (generalists). Moraxellaceae, Enterobacteriaceae, and Pseudomonadaceae were highly prevalent in specialist species, and also present in eggs, while Rickettsiaceae associated exclusively with generalist beetles. Bacteria isolated from
digestive systems had distinct capabilities and suggested a possible beneficial role in both digestion of plant-based compounds, including xylose, mannitol, and pectin, and possible detoxification, via lipases.
species are currently expanding their diets to include exotic invasive plants, yet it is unknown whether their microbial community plays a role in this transition. In this study, colonization of invasive plants was correlated with a dysbiosis of the microbiome, suggesting a possible relationship between gut bacteria and niche adaptation.
Understanding tropical biology is important for solving complex problems such as climate change, biodiversity loss, and zoonotic pandemics, but biology curricula view research mostly via a ...temperate-zone lens. Integrating tropical research into biology education is urgently needed to tackle these issues.
The Organization for Tropical Studies (OTS) has played a pivotal role in our understanding of tropical ecosystems' structure and function. For more than fifty years, OTS has contributed to the ...training of three generations of tropical biologists and facilitated, supported, and promoted leading-edge research in its field stations. Plant reproductive ecology and genetics have been a significant focus of OTS research since the early 1960s, and Dr. K.S. Bawa made a significant contribution to the advancement of this field. His work improved our understanding of the diversity and evolution of breeding systems in tropical forests, their phenology and pollination ecology, and their mating and genetic structure. We argue that his work inspired other tropical biologists' work and used the work of one of the authors for illustration when appropriate. We point out the need for research in critically important topics to slow down biodiversity loss, prevent the collapse of tropical systems in a changing climate, and the emergence of zoonotic disease. We suggest future research topics for the OTS field stations, including in plant reproductive biology.
Urban landscaping conversions can alter decomposition processes and soil respiration, making it difficult to forecast regional CO2 emissions. Here we explore rates of initial mass loss and net ...nitrogen (N) mineralization in natural and four common urban land covers (waterwise, waterwise with mulch, shrub, and lawn) from sites across seven colleges in southern California. We found that rates of decomposition and net N mineralization were faster for high-N leaf substrates, and natural habitats exhibited slower rates of decomposition and mineralization than managed urban landcovers, especially lawns and areas with added mulch. These results were consistent across college campuses, suggesting that our findings are robust and can predict decomposition rates across southern California. While mechanisms driving differences in decomposition rates among habitats in the cool-wet spring were difficult to identify, elevated decomposition in urban habitats highlights that conversion of natural areas to urban landscapes enhances greenhouse gas emissions. While perceived as sustainable, elevated decomposition rates in areas with added mulch mean that while these transformations may reduce water inputs, they increase soil carbon (C) flux. Mimicking natural landscapes by reducing water and nutrient (mulch) inputs and planting drought-tolerant native vegetation with recalcitrant litter can slow decomposition and reduce regional C emissions.
The existence of monodominant forests on well-drained soils in tropical regions has been widely reported. Such forests most likely result from a combination of both ecological and evolutionary ...factors. Under conditions of high seed and seedling mortality, vegetative reproduction could create a reproductive advantage leading to forest dominance, and profoundly affect the distribution of genetic variation in a clonal species. We investigated these effects in a low diversity forest site in Northeastern Costa Rica dominated by the species Pentaclethra macroloba, which sprouts from the root mass of fallen trees and from snapped trunks. We examined the population structure of juvenile P. macroloba growing in different soil types and across an elevational gradient. Using seven molecular markers, we genotyped 173 juvenile P. macroloba from 18 plots (six plots in seasonally inundated swamps, and 12 plots in upland non-swamp) spanning 50-300m in elevation at La Selva Biological Station and the adjacent Reserva Ecológica Bijagual in Northeastern Costa Rica. We answered two specific questions: (1) How extensive is clonal reproduction? and (2) what is the distribution of genetic diversity and structure? We found that clonal reproduction occurred exclusively within inundated swamp areas. However, there was no significant difference between genetic diversity measures in swamp and non-swamp plots, which were both generally low when compared with other tropical forest species. Genetic structure was significant across all plots (F(ST) = -0.109). However, genetic structure among swamp plots (F(ST) = 0.128) was higher than among non-swamp upland plots (F(ST) = 0.093). Additionally, spatial autocorrelation among individuals within non-swamp upland plots was significant from the 25 to 100m spatial scale, but not within swamp plots. The degree of overall genetic structure we found in P. macroloba is high for a tropical forest tree. The incidence of clonal reproduction is a contributing factor in genetic differentiation, but the high structure among plots without clonal reproduction indicates that other factors contribute as well.
Understanding tropical biology is important for solving complex problems such as climate change, biodiversity loss, and zoonotic pandemics, but biology curricula view research mostly via a ...temperate-zone lens. Integrating tropical research into biology education is urgently needed to tackle these issues.
The existence of monodominant forests on well-drained soils in tropical regions has been widely reported. Such forests most likely result from a combination of both ecological and evolutionary ...factors. Under conditions of high seed and seedling mortality, vegetative reproduction could create a reproductive advantage leading to forest dominance, and profoundly affect the distribution of genetic variation in a clonal species. We investigated these effects in a low diversity forest site in Northeastern Costa Rica dominated by the species Pentaclethra macroloba, which sprouts from the root mass of fallen trees and from snapped trunks. We examined the population structure of juvenile P. macroloba growing in different soil types and across an elevational gradient. The incidence of clonal reproduction is a contributing factor in genetic differentiation, but the high structure among plots without clonal reproduction indicates that other factors contribute as well.Original Abstract: La existencia de bosques monodominantes sobre suelos bien drenados en regiones tropicales ha sido ampliamente reportada. Investigaciones recientes han sugerido que tales bosques son probablemente resultado de una combinacion de factores ecologicos y evolutivos. Bajo condiciones de alta mortalidad de semillas y plantulas, la reproduccion vegetativa podria crear una ventaja reproductiva llevando a la dominancia del bosque, pero tambien podria afectar profundamente la distribucion de la variacion genetica en especies clonales. Investigamos estos efectos en un sitio de bosque con baja diversidad de especies en el Noreste de Costa Rica que es ampliamente dominado por la especie Pentaclethra macroloba, la cual retona de la masa de raices de arboles caidos y de troncos partidos. Examinamos la estructura poblacional de individuos juveniles de P. macroloba creciendo en diferentes tipos de suelo y a traves de un gradiente de altitud. Utilizamos siete marcadores moleculares, genotipamos 173 Pentaclethra macroloba de 18 parcelas (seis en cienagas y 12 en ambientes no cenagosos) ubicados en un gradiente de elevacion entre 50-300m en las reservas adyacentes: Reserva Biologica B ij agua I y Estacion Biologica La Selva, en el centro de Costa Rica. Abordamos dos preguntas especificas: (1) ?Que tan extensa es la reproduccion clonal? y (2) ?Cual es la distribucion de diversidad y estructura genetica? Encontramos que la reproduccion clonal ocurrio exclusivamente dentro de areas cenagosas inundadas. La estructura genetica fue significativa en todas las parcelas (F sub(ST)=0.109). Observamos una estructura genetica mas alta entre poblaciones juveniles dentro de las cienagas (F sub(ST)=0.128) comparada con poblaciones no cenagosas en parcelas a mayor altura (F sub(ST)=0.093), con mayor autocorrelacion espacial en sitios no cenagosos en el intervalo entre 25 y 100m. La presencia de reproduccion clonal no afecto significativamente las medidas de diversidad entre las dos areas, que fueron generalmente bajas comparadas con otras especies de bosque tropical. El alto grado de estructura genetica en general es novedoso para un arbol de bosque tropical. La incidencia de reproduccion clonal es un factor que contribuye en la diferenciacion genetica, pero la alta estructura en parcelas sin reproduccion clonal indica que otros factores estan contribuyendo tambien.
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