This collection contains the findings of scientific studies of tropical terrestrial and marine ecosystems, their components, and their conservation from Monteverde, Cuajiniquil, and other areas of Costa Rica.
This digital collection is a service of the Monteverde Institute, whose mission is to catalyze social, ecological and economic sustainability by integrating community initiatives with education, research and conservation.
Esta colección contiene los hallazgos de estudios científicos de ecosistemas tropicales terrestres y marinos, sus componentes y su conservación de Monteverde, Cuajiniquil y otras áreas de Costa Rica.
Esta colección digital es un servicio del Instituto Monteverde, cuya misión es catalizar la sostenibilidad social, ecológica y económica integrando iniciativas comunitarias con educación, investigación y conservación.
Orchids are one of the most diverse organisms in Costa Rica with over 1460 documented species. They are unique in their germination and early juvenile life stage in that their survival is dependent on mychorrizae symbiosis. Though the symbiosis is only thought to be obligatory in the juvenile life stage, mature orchids are often found to maintain mychorrizal associations. I used lactophenol blue dye to compare the mychorrizae colonization points in Epidendrum radicans, a terrestrial orchid, and Epidendrum piliferum, an epiphytic orchid, in Monteverde Costa Rica. The intention of my study was to determine if mychorrhizae colonization in orchid roots was significantly different in epiphytic orchids with arboreal soil and terrestrial orchids. I found a significant difference between the mean colonization points for each species’ roots. As expected, the terrestrial orchids had a higher abundance of orchid mychorrizae colonization points. I also compared the presence of hyphal structures from the family Glomeraceae in each orchid species. My results showed no significant difference in the presence of branched or blurred hyphal structures between the two species despite the difference in the abundance of orchid mychorrizae. The difference in abundance of mychorrizae between the terrestrial and epiphytic orchid is likely attributed to a difference in nutrient availability.
Assessing different soil properties in primary forest, pasture, and regenerative forest in Los Llanos, Monteverde
Animal agriculture is one of the largest causes of deforestation, converting primary and secondary forest into pasture for cattle. By severely altering the landscape, major ecosystem changes occur, including changes in soil properties. I compared the soil of four types of land plots in Las Llanos, Monteverde: primary forest, pasture, reforested pasture, and fallow pasture. I tested the compaction, decomposition rate, presence of water stable aggregates, and arthropod diversity within each plot. Primary forest had significantly lower compaction, and seemed to have higher decomposition rates and higher proportions of large aggregate sizes. The reforestation site resembled both pasture and fallow pasture, especially in the case of compaction and decomposition. The four sites had individuals from many of the same arthropod orders, but primary forest had the highest number of individuals. Of the four sites, the primary forest seemed to have better soil quality than the others. The lack of regeneration in the reforested soil may suggest that forest does not return quickly to its natural state. Thus, when considering ecosystem protection, conservational efforts should be prioritized.
Samantha E. Simon
Galls are abnormal plant growths induced by highly specialized arthropods and are used as a food source and for protection for the developing larvae. The chemical composition within galls is known for containing high levels of tannins, which have anti-fungal and anti-herbivory properties. This study focuses on the effect of tannins and other chemicals extracted from Quercus cortesii galls on the inhibition of the fungi Mycena citricolor. This study also explores the presence of gall-invaders such as arthropods and vertebrates. Two methods of treatment were used to determine the effect that tannins and other chemicals extracted from cynipid wasp galls found on the tree Quercus cortesii, have on fungal growth. One method, denoted as tannin agar, tested a tannin-infused substrate and showed that fungal growth is inhibited by the presence of gall extracts. The other method, denoted as tannin droplets, tested the effect of tannins after the fungus had already been established and showed no effect on the fungal growth. All of the data was analyzed using a one-way ANOVA and found that the tannin agar treatment had significantly less fungal growth and slower growth rate than the control treatment. The tannin droplet treatment showed no difference in fungal growth and growth rate when compared to the control treatment. Twelve galls were also collected and dissected to determine whether arthropods invade and use the gall after the cynipid wasps have left. At least thirty morpho-species of arthropods use the galls for feeding and protection. Additionally, it was observed that as the gall becomes wet, the diversity of morpho-species decreases. Lastly, camera traps revealed coatis could also be using the fallen galls to feed from.
Medicinal plants in Monteverde: Efficacy and local use of Neurolaena lobata (Gavilana) and Ageratum conyzoides (Santa Lucia) against E. coli and S. aureus
I examined the antimicrobial efficacy of both Neurolaena lobata and Ageratum conyzoides found in Monteverde. These two plants are in the Asteraceae family, and can be used to treat gastrointestinal discomfort. Both have been proven to be effective antimicrobials against E. coli and S. aureus. I tested each plant on E. coli and S. aureus using a Kirby-Bauer assay and an agar well diffusion method. For Neurolaena lobata plated on S. aureus, solutions of young leaves exhibited significantly higher inhibition zones than solutions of both old leaves and control disks. I also gathered local knowledge on medicinal plants using a survey method, in which 31 participants responded to questions regarding their use and knowledge of medicinal plants. Twenty nine out of 31 participants use medicinal plants in some way, and at least 12 different families of medicinal plants are used in Monteverde.
Pesticide drift from organophosphate insecticides near industrial farms is a big problem in Costa Rica. Excess organophosphates run into waterways and nearby soils, where they bioaccumulate in the foods grown there and in the drinking water, causing health problems to those who consume them. Some mushrooms have bioremedial effects on pesticides. Trametes versicolor, a species of white rot fungi, can break down organophosphates by secreting chemicals that catalyze degradation reactions in soils. To determine if this is a viable option for bioremediation in the tropics, I observed four Trametes spp. fruiting bodies and one substrate without fungus after adding Malathion organophosphate pesticide. I observed pH, organophosphate content, and insect presence and species richness over a period of 11 days to quantify the mushroom’s effects on the pesticide. On the substrates with mushrooms, pH was significantly higher than the substrate without. This is beneficial because high pH promotes hydrolysis of organophosphates, which is the process by which these pesticides are most successfully broken down and removed from the environment. Substrates with mushrooms also had greater insect presence and insect species richness than the substrate without, even after pesticide application. Thus, I hypothesize that Trametes spp. fungi are altering soil pH and creating an environment conducive to organophosphate breakdown, which means they could be viable options for bioremediation.
Animals use a variety of traits such as brightly colored plumage, nuptial gifts, chemical signaling, or intricate displays to attract mates. Long-tailed manakins (Chiroxiphia linearis) exhibit one of the more elaborate mating rituals found in the animal world. C. linearis form lek mating systems, where a group of males aggregate for cooperative courtship displays. They perform an alpha-beta duet that serves as a long-range cue to attract females to their perch zone for further display. Higher frequency matching in this duet has been correlated to higher courtship success. I investigated differences between alpha-beta vocalizations within and between leks, as well as the relationship between their song performance and proximity to other leks. By collecting data at 12 lekking sites and analyzing 426 vocalizations, I found a correlation between low and high frequency differences, and a negative correlation between index frequency matching ad index time matching. This suggests a female preference for overall frequency matching versus song synchronicity. I found no significant relationship between relative proximities of leks and either time matching or frequency matching. This could indicate that long-term partnerships and duet practice in C. linearis are more important than competition in increasing song performance.
Structural benefits and distribution of cribellar thread in adult Tengella radiata webs (Araneae: Tengellidae)
Tengella radiata is a spider endemic to Costa Rica whose webs change as spiderlings mature into adulthood. As adults, a key component of their webs is their use of cribellar thread, spun from a specialized silk-producing organ, the cribellum. This paper seeks to figure out what the structural benefits and distribution of this silk in adult Tengella radiata webs. To address this question, I analyzed thread density in different regions of the web, the amount of cribellar thread used in different segments of the web, and tested thread resistance in cribellar and non-cribellar thread. I found that the area near the spider’s tunnel has a higher thread density with little to no cribellar thread, while the periphery of the thread has less thread density but also has the highest amount of cribellar thread. I also found that cribellar thread is three times stronger than non-cribellar thread. This is an indicator that their web structures have a different arrangement according to web location. This could also be relevant for establishing a specific prey capture technique.
Mina M. Patel
The production and use of mosquito insecticides has long been practiced; presently, the search for natural insecticides and larvicides is a flourishing field. Natural insecticides and larvicides persist less in the environment and are less toxic than synthetic insecticides such as DDT (dichloro-diphenyl-trichloroethane). I studied the effectiveness of citronella grass, Cymbopogon nardus, as a larvicide against Culex quinquefasciatus and Culex nigripalpus mosquito larvae and how it affected their behaviors. The larvae were exposed to three different treatments: two self-prepared extractions of citronella oil of different concentrations and a natural commercialized citronella repellant spray. I recorded the number of deaths and behavioral changes before and after the treatment twice a day. Results showed that larvae mortality between the control group and the three treatments were significantly different. The two citronella oil extraction treatments collectively killed an average of 52% of the larvae and the commercial spray killed 100% of the larvae. The treatments also induced the larvae exposed to the citronella oil to progress in the life cycle more rapidly than the larvae in the control group. The larvae exhibited new behaviors after exposure to the citronella essential oil as well. The sudden behavior change after adding the citronella essential oil is key evidence that the citronella oil is immediately affecting the larvae. The results I obtained from this study suggest that the leaf and aerial parts essential oils of C. nardus are potential natural larvicides against C. quinquefasciatus and C. nigripalpus larvae.
This study investigates the relationship between soil pH, caffeine content in leaves, and disease prevalence in Coffea arabica. Caffeine is a secondary metabolite that acts as an insecticide and antimicrobial to protect the coffee leaves, shoots, and fruits from fungus and herbivory. I used caffeine water extraction and UV/V spectrophotometry to analyze the caffeine content in leaf samples from a total of forty trees in four different sites at the Life Monteverde farm in Cañitas, Guanacaste. At each tree a soil sample was collected for pH analysis and a disease survey was conducted for Hemileia vastatrix, Mycena citricolor, and herbivory. Additionally I measured temperature, soil moisture, and light levels at each tree and compared between plots to see if there were significant differences in these factors depending on location. I compared disease prevalence, caffeine content, and soil pH amongst the forty sampled trees and found no significant difference between any of these three factors. The results from this study suggest that leaf caffeine concentration is dependent on other factors.
Cephalopoda is a varied and unusual class that has occupied oceanic habitats all over the world for millions of years. One species in particular, Octopus vulgaris, or the common octopus has a nearly global range. Because of their soft bodies and lack of hard, protective outer covering octopuses are highly vulnerable to numerous predators. However, octopuses have evolved to compensate for this loss with a number of other anti-predator defenses, namely camouflage and substrate-hiding. Camouflage allows the octopuses to alter their appearance into a variety of colors, textures and shapes as they move through their environments, hiding in plain sight from predators. Substrate-hiding allows octopuses to use their surroundings to their advantage, as they squeeze their malleable bodies into spaces in the substrate that are inaccessible to most predators. My study seeks answer whether or not there is a species-wide manner in which octopus display anti-predator behaviors or if there is individual variability in these behaviors. My results showed that individual octopus react differently in both their rate of camouflage and the types of camouflage displayed when exposed to the same stimuli. This variability in their reactions is reflective of their ability to thrive in the wide range of habitats they occupy throughout the world. In contrast, three distinct behavioral phenotypes emerged with respect to substrate-hiding; octopus either spent all their time hiding, all their time exposed, or half their time hiding and half their time exposed. These shared phenotypes show that substrate-hiding does not need to be highly varied between individuals in order to be effective against a wide range of predators. My experiment highlights the importance and effectiveness of these behaviors in allowing the octopus to avoid, deter and escape predators all over the world, contributing to its global success.
Archinsects and arachnitects: The leaf structures that arthropods construct in the protected areas of Monteverde
This study aimed to understand which insect and arachnid families manipulate leaves to make shelters and for what purposes they make them. I investigated the types of structures they create and how this may benefit their survivorship within three diverse protected areas of Monteverde- Estación Biológica Monteverde, Bajo del Tigre and Rachel Dwight Crandell Reserve. I collected a total of 56 individuals in the orders Lepidoptera, Araneae, and Orthoptera. I quantified the different types of leaf modifications made as well as the plant family in which they were made. I wanted to determine if there was specificity within the different families. The most abundant family I found was Anyphaenidae—a family of arachnid, and this was the only family collected at all three of my sites. I also found that there were different uses for the leaves, which I classified as shelter, feed, molt, pupate, and eggs—and I described the refuge that each individual created (by structure and plant family) and compared them. An interesting result is this area houses a unique cricket, which is the one of two families in Orthoptera that spins silk. Furthermore, I did not find species specificity in the family of arthropod’s plant choice—this could be due to insufficient data collected from each family of arthropod especially in the order Lepidoptera.
Call variation in mixed-species and single-species flocks of the common Chlorospingus in Monteverde, Costa Rica
The Common Chlorospingus (Chlorospingus flavopectus opthalmicus) is a common highland bird found from Mexico to Bolivia that travels and forages in mono- especific and mixed-species flocks. When foraging in mixed-species flocks, the Common Chlorospingus plays an integral role as a nuclear species and forages primarily for arthropods instead of fruit. The purpose of this study was to determine whether or not there is a difference between chlorospingus chip calls in mixed species versus single species flocks, and if there is then to explore why they exhibit this difference. I recorded the calls of C. ophtalmicus both in single species and in mixed species flocks and analyzed them using Raven Pro 5.1 sound analysis software. I found that the calls of the common chlorospingus in mixed-species flocks had lower high frequency, a smaller frequency range, and longer call duration than in single species flocks. These findings lean toward support of the Acoustic Adaptation Hypothesis, which states that animals can adjust their calls to best suit their environment. Chlorospingus in mixed flocks might lower their calls in order to increase sonic transmission, in response to denser vegetation when arthropod foraging, more background noise from other bird species, or increased flock size. The influence of these three factors on chlorospingus calls should be further studied to better understand the effect that different foraging strategies can have on C. ophtalmicus calls.
Kathleen E. Knight
As the number of jaguars in captivity grows, the need to better understand the activity level and behavioral effects of captive jaguars increases. By understanding the specific activities and behaviors of jaguars in captivity, it is possible to better provide for the overall health of these animal in rescue centers, zoos, and wildlife sanctuaries. This first part of this study consists of a comprehensive activity budget report, which assesses the activity and inactivity levels in a male jaguar and female jaguar at the Centro Rescate de Las Pumas in Cañas, Guanacaste, Costa Rica. These activity budgets were constructed through an observational study consisting of daytime, early morning, and evening observations, and nighttime camera trapping. The second part of this study explores the effectiveness of various forms of environmental enrichment, and makes recommendations to encourage incorporation of knowledge about individual jaguars into forms of environmental enrichment designed to improve the quality of life of captive jaguars. Activity of the two jaguars was found to differ between each individual, and a higher level of activity during the late night and early morning, but was overall much lower than that of jaguars in the wild as reported by Rabinowitz and Nottingham in 1985. Different stimuli in the environmental enrichment study produced different scores of effectiveness, with commercial perfumes intended for human use and logs scented with male jaguar scent scoring the highest. This study recommends that rescue centers understand individual jaguars through activity budget reports and individual behaviors, and take measures to provide environmental enrichment for captive jaguars in order to increase their levels of activity and overall wellbeing.
Comparing tardigrade abundance and diversity on rock, log, live tree, and canopy in Monteverde, Costa Rica
This study surveyed the abundance and diversity of Phylum Tardigrada across four different substrates: rock, log, live tree, and canopy, in Monteverde, Costa Rica. Tardigrades are understudied micro-invertebrates that inhabit every biome on the planet. I collected twenty-eight samples, or 140 subsamples, by hand, soaked them in water for a minimum of four hours, and surveyed for tardigrades. I found and documented forty-five tardigrades. Ninety-one percent of tardigrades found were Class Eutardigrada, while the remaining nine percent were Class Heterotardigrada. Five genera were identified: Echiniscus, Pseudechiniscus, Macrobiotus, Paramacrobiotus, and Minibiotus. The canopy and live tree substrates produced equal abundance and diversity levels, each with 18 Eutardigrades and two Heterotardigrades. The log substrate had three tardigrades and the rock substrate had only two, all Eutardigrada. Although the canopy and live tree substrates yielded the same results, tardigrades found in the canopy were more consistently found in all seven of the canopy samples. The tardigrades found on the live tree substrate, however, were primarily found all in one sample. This may indicate that tardigrade abundance is consistently higher in the canopy, but has a more patchy, random distribution in live trees. In conclusion, tardigrades are abundant and diverse in the canopy of the cloud forest in Monteverde, Costa Rica.
Comparison of spider abundance and diversity in different habitats in the Life Monteverde coffee farm
Coffee agroecosystems have abundant insect prey, and therefore have the potential to support a high diversity of spiders. In this study, I measured spider diversity in the Life Monteverde low-shade coffee farm located in Cañitas, Guanacaste, Costa Rica. I compared the alpha and beta diversity of an isolated coffee field, a forest-surrounded and more highly shaded coffee field, and a forest patch all located on the farm. At each site, I collected spiders from 12 plots, and later I identified each spider to the family level. In total, I collected 508 individuals of 15 families. Using the true diversity index, I found that the isolated field had the highest family richness, while the forest patch had the highest alpha diversity when considering evenness of family distribution. The isolated field and the forest-surrounded field had the most family overlap according to the Jaccard index, which measures beta diversity. Theridiidae was the most common family found in each site, and the second-most common family varied among sites. These results suggest that while low-shade coffee growing can support a high diversity and abundance of spiders, populations may be dominated by a few families. The high family complementarity between the two most similar sites, the fields, indicate that habitat composition, rather than proximity to forest, has a greater effect on the presence of specific spider families.
The goal of protected areas is to protect the flora and fauna contained within them. Tourism may adversely affect the species contained in the protected area while also generating revenue to keep a protected area open. This study aimed to find if there is a correlation between number of tourists and the abundance of wildlife within the Monteverde Cloud Forest Biological Reserve. Mammal and bird abundance and tourist abundance estimates were made using Bushnell HD camera traps over 96 trap nights. A positive correlation was found between the number of visitors and the number of animal individuals photographed at night (R2=0.1461), the number of species photographed (R2=0.2227) and the number of positive captures (R2=0.1948). My results indicate that in this season the number of tourists in the Monteverde Reserve does not have a negative effect on the wildlife there and that tourism in the Reserve is sustainable from the point of view of animal use of the area.
Taryn Sena Dunivant
Most tropical forests consist of a dense stem count, presenting many opportunities for epiphytes to find a niche and diversify. Orchidaceae is a strong example of biodiversity in a tropical cloud forest, which is supported by representing one of the largest families within angiosperms and containing countless epiphytic species. Their unique abilities to survive as epiphytes are showcased in their complex root systems. A key structure to these impressive root systems are the outermost layer termed the velamen. The velamen is comprised of spongy dead cells ranging from one to eighteen cells thick. This sheath-like layer serves as a source of protection and absorption for the interior of the system, and consequently the overall fitness of the plant. Examining these root systems among genera and relating them to each other may give insight to how closely similar or different the root systems are between genera. Six common orchid genera (Lepanthes, Restrepia, Masdevallia, Epidendrum, Maxillaria, Oncidium) of Monteverde, Costa Rica were selected and their root systems were studied. I took measurements of the root diameter, velamen thickness, and the number of cells thick the velamen was. Overall there was a positive correlation found between the root diameter and the thickness of the velamen, though not in all genera (e.g Epidendrum). Correspondingly, as the thickness of the velamen increases, the number of cells increases. Orchidaceae root systems have very little variation in some genera and in others are widely variable. This study shows how the root systems of Orchiaceae can differ both between and within genera.
Coleoptera, or more commonly known as beetles, are the largest and most diverse order within the arthropods. This study aimed to categorize the diversity between diurnal and nocturnal beetles as well as determine if there are distinguishing phenotypes between the two groups. For a total of five days, I collected diurnal and nocturnal beetles throughout the tropical cloud forests of the Monteverde zone in Costa Rica and identified to Family. For each species, I recorded the size, coloration (number of colors visible and light versus dark tones), pattern, texture, and iridescence and compared between diurnal and nocturnal beetles. With respect to diversity, my results revealed that while diurnal beetles are more diverse within the leaf beetle family, Chrysomelidae, nocturnal beetles have the highest diversity within the scarab beetle family, Scarabaeidae, indicating that diurnal or nocturnal activity may be more correlated the taxonomic category than to individual species phenotypic traits. This is further supported by the presence of exclusively diurnal as well as exclusively nocturnal families in my data. T-test analysis proved size to be not correlated with beetle diurnal or nocturnal activity. The only phenotypic significant difference I discovered was that nocturnal beetles are darker in coloration than diurnal beetles, indicating that the darker tone is possibly an adaptation for nocturnal beetles to remain hidden while active in the darkness of the night. Other phenotypes may instead show more correlation to crypsis, aposematism, and sexual selection than diurnal and nocturnal activity.
Ectoparasite abundance and diversity on farm animals in Monteverde and San Luis along an elevation gradient
Abundance and diversity of arthropods are largely dependent on climate. Elevation gradients provide different microclimates that can support a unique number and variety of species. In order to test the effect of elevation on abundance and diversity of arthropod ectoparasites, I collected samples on four different farms: Life Monteverde and Benito Guindon’s farm in Monteverde at about 1,800 m, and Lelo Mata’s farm and Tim Sayles’ farm in San Luis around 700 m. At each elevation, I compared abundance and diversity of ectoparasites on dogs and cattle. I found a presence of Ctenocephalides and Pulex fleas on dogs, and 22 different morphospecies of ticks on cattle. Trends in the data show a higher abundance of fleas and a greater diversity of tick morphospecies sampled at low elevation. It is likely that ectoparasites will experience a change in abundance and distribution among and between elevations as global warming continues to adjust microclimates. Therefore, it is important to understand their current abundance and distribution to best prepare for the effects of climate change. Additionally, data from goat samples collected on the farms in Monteverde reveal a presence of Damalinia caprae lice. The higher number of adult and total lice on Life Monteverde indicates a more-established population than the nymph-dominated population on goats at Benito Guindon’s farm. This difference in abundance is due to differing ectoparasite control practices and living conditions of animals on each farm. Difference in lice abundance between farms at the same elevation is evidence that ectoparasite abundance can be controlled through best practice management.
Edge effect on moth richness, abundance, and potential pollination activity in a Costa Rican cloud forest
Habitat loss and fragmentation are major threats to biodiversity, especially in tropical forests which house most of the world’s species. Edge effects are important considerations when investigating the impact of forest fragmentation on biodiversity, as they can lead to large, and often detrimental shifts in population, community, and ecosystem stability. The taxa-specific effects of forest edges are complex, highly variable, and poorly understood. In this study, I investigated the edge effect on moth richness, abundance, and potential pollination activity in a fragmented tropical cloud forest in Monteverde, Costa Rica by sampling moths with light traps at two different locations: in the forest interior, and at the forest edge. My results suggest that there is a negative edge effect on moth richness, abundance, and potential pollination activity probably caused by wind. By shedding light on the possible edge effects on this extremely diverse and ecologically important taxon, this study provides valuable preliminary insights to ecologists and conservationists working to slow the loss of biodiversity in tropical forests.
Effectiveness of the minima caste of the Leafcutter Ant (Atta cephalotes) on cleaning harvested leaves
Leafcutter ants have been practicing agriculture longer than humans themselves. Leafcutter ant species, Atta cephalotes, common to Central and South America, cultivate a unique fungus, Leucocoprinus gonogylophora, that sustains the lives of millions of leafcutter ants within a single colony. In order to be efficient farmers, A. cephalotes have developed a caste system consisting of a queen, soldiers, workers, and minima. Each caste has a specific role within the colony, however, the role of the minima is still highly debated among scientists. It is hypothesized that the minima clean the surface of the leaves collected from nearby plants on the trail from the plant source to the entrance of the colony. Using two different methods, the cleanliness of the leaves at the leaf source and the entrance to the colony were observed. The first method consisted of placing the leaf sample onto an agar plate, while the second method consisted of swabbing the leaf surface of the samples onto an agar plate and observing whether the samples presented fungal growth or not. Overall, it was shown that there was little difference between leaf cleanliness, as both the leaf source and the colony entrance had 60% of the samples grow fungus, however, other patterns, such as fungal diversity and presence of mites were observed and analyzed. On average, there was a higher diversity of fungi at the leaf source compared to the entrance of the colony which may suggest that the minima may only be cleaning for certain types of fungi. A presence of mites found exclusively on samples taken from the leaf source could suggest that minima also clean off pests from the leaves. These results seem to indicate that the role of the minima is crucial to the colony, as they perform multiple unique tasks in order to protect their precious food source.
Effect of elevation on the composition and eco-physiological strategies of canopy epiphytes in a tropical montane cloud forest
Tropical montane cloud forests have a high diversity and abundance of epiphytes that have drought resistance adaptations to the water and nutrient limitations in the canopy. Most epiphytes in the canopy have drought adaptations and may have different distributions along the vertical gradient of a single tree in addition to varying at a landscape scale such as with elevation. Vascular epiphyte composition and eco-physiological strategies were studied along an elevational gradient of 1400-1830m in a cloud forest in Monteverde to see if there is a variation in diversity, abundance, and drought adaptation characteristics. I measured morphospecies diversity, abundance, foliar water uptake capacity, and leaf toughness for epiphytes on fallen branches. The prevalence of other traits such as succulence, trichomes, and pseudobulbs in orchids were also compared across elevations. I also measured the canopy cover, branch diameter, and humus mat thickness of each branch measured to look at preferred local substrate characteristics. No significant trends were found between elevation and epiphyte morphospecies diversity, abundance, foliar water uptake capacity, or leaf toughness even among individual families. There were slight positive trends between morphospecies diversity with branch diameter and humus mat thickness which may suggest that local substrate preferences are more influential in determining the composition of epiphytes rather than large scale characteristics like elevation.
White-faced capuchins (Cebus capucinus) are omnivores that forage in tree canopies eating mostly fruits. Though many previous studies have been done on the foraging behavior and diet of white-faced capuchins, there is little information available on their feeding behavior in terms of fruit dropping while eating. This study was done on a group of 13 wild white-faced capuchins in Bajo del Tigre, Monteverde, Costa Rica over a two-week observational period. I observed the feeding behavior of the white-faced capuchins, including number of fruit pieces dropped by the capuchins during 30-second focal observations. I noted animals, such as agoutis, that were feeding on the dropped fruit to determine what animals were taking advantage of the fruit dropped by the white-faced capuchins. I found that, on average, white-faced capuchins dropped 5.2 pieces of fruit per 30-second observation period. My data demonstrates that there was a significant difference in dropping amount for different fruit types as well as significant differences in the presence of agoutis feeding for different fruit species. The majority of the time white-faced capuchins were feeding, other animals were feeding on the fruits the capuchins dropped, this suggests the majority of those fruits are being either dispersed further or are being fed on by other animals. Overall, my data suggest that white-faced capuchins make fruits more accessible to ground-foraging animals and in turn aid in second-degree dispersal of those fruits. Further research would be beneficial in looking at fruit selectivity in white-faced capuchins and determining the fate of the dropped fruits that were not fed on by other animals during the time the capuchins were feeding.
Glasswing butterflies, of the subfamily Ithomiinae, feed almost exclusively from plants that produce pyrrolizidine alkaloids as secondary metabolites. They are able to extract the alkaloids from the nectar and use them as pheromones, as well as for chemical defense. The most common of these alkaloid-producing plants in the Monteverde zone is Santa Lucia, an Asteraceae. In order to determine what attracts Ithomiinae to these flowers, I presented them with three types of Santa Lucia flowers: unmodified flowers, dried flowers, and red-colored flowers. If the butterflies respond to visual cues, I predicted that they would visit the unmodified and dried flowers more frequently. If they are able to sense the contents/presence of the nectar, I predicted that they would visit the unmodified and colored flowers more often. If Ithomiinae recognize both of these factors, I predicted that they would show a preference for visiting the unmodified flowers. After four and a half days of observation, I found that Ithomiinae visit unmodified flowers three times as often as dried or colored flowers. However, the length of each visit is highly variable, and does not correlate with visiting preference. This supports my prediction that Ithomiinae acknowledge both flower color, and nectar amount when selecting flowers. Omitting outliers, the average durations of the three presented flower types are not statistically significant, meaning that the butterflies visited each flower type for similar amounts of time.