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.
We investigated the effects of plant density, plant diversity, and light availability on susceptibility of saplings of Stryphnodendron microstachyum Poeppig and Endlicher to attack by herbivores and ...pathogens in the lowlands of northeastern Costa Rica. Seedlings of S. microstachyum were planted at either low or high density. High density stands were planted in a environments with 2 plant diversities within each environment: monocultures in abandoned pastures (=sun) and in 5-yr-old secondary forest (=shade), or polycultures in which S. microstachyum was planted with 4 other species also in sun and shade. Low density stands consisted of isolated individuals in 4 types of sites (abandoned pasture, secondary forest understory, primary forest understory, and primary forest light gap). Numbers of galls (Diptera: Cecidomyiidae), larvae (Lepidoptera: Noctuidae: Euclystis), and fungal spots (Melanconiales: Pestalotia) were greater in the high density stand than in low density stands, and greater in the shade than in sun. We found no differences in infection between monocultures and polycultures at high density, nor did we find Euclystis larvae or Cecidomyiidae galls in low density stands. Numbers of fungal spots per leaf and density of galls were greater on larger plants. These data suggest that higher plant densities increase the probability of attack by herbivorous insects and leaf pathogens, and that plantations of tropical native tree species in partial shade, as a means of reforestation, run the risk of outbreaks of normally rare plant enemies. Furthermore, the observed positive relation between plant size and attack suggests that plantations of this tree species will become more susceptible to pest outbreaks as the trees mature
Under closed canopy, vegetation cover varies as much as 20 percent at ground level at the lowland rain forest study site, Estacion Biologica La Selva, in Costa Rica. To determine the effect variation ...in understory cover has on seed germination and seedling establishment, we followed the fate of naturally germinating seeds in treatment plots in which the understory vegetation had been removed, and in neighboring control plots. The overstory canopy was left intact in all plots. Average cover values for treatment and control plots were 85.0 and 90.4 percent, respectively. After a 3.5-mo period, we found no differences due to the treatment in germination or survival of new seedlings, suggesting that variation in understory vegetation had little influence on establishment compared to that of the overstory canopy during this time period.
A native California perennial grassland was sampled for grasshopper populations. The grassland is managed for the preservation of the native perennial bunchgrass, Nassetta pulchra Hitch. Grasshopper ...density, biomass, diversity, and richness were measured from July 1993 to October 1994. Average density of all grasshoppers was 2.30 hoppers/m² (0.66 s) for 1994 (June through August). Overall forage consumed for 1994 was 140 kg/ha, suggesting that grasshopper populations exist at economically damaging levels. Grasshoppers do not appear in the grasslands until late spring, after annual grasses have set seed. Biomass of grasshoppers peaks in July when adults are predominant. Both grasshopper density and biomass were higher in 1993 than in 1994, and a total of 5 species were found throughout the study. Melanoplus sanguinipes Fabricus dominated the acridid communities and accounted for more than 95% of the individuals.
Agalychnis calcarifer is a poorly known species distributed in humid lowland forests of Costa Rica, Panama, Colombia, and Ecuador. The authors describe egg deposition site, development and morphology ...of the tadpole and color changes in froglets of A. calcarifer from an Atlantic lowland site in Costa Rica.
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