Monteverde Institute: Tropical Ecology and Conservation

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  Effect of different germination processes on belowground and aboveground productivity in mature Coffea arabica, November 2008

  Emily Giles

  This was the first study in Monteverde, Costa Rica to look at how the agricultural method used during the germination phase affects the productivity of a mature Coffea arabica. It was thought by local farmers that a plant germinated in the ground and then transplanted would have more fine root biomass than a plant that is germinated in a polybag and then transplanted. Traditional farming practices have shown that when coffee is transplanted from the ground to another location; the main root is often cut, yielding more secondary fine roots. In contrast, many experiments have found that polybags increase a plant’s productivity by protecting root growth (Shu-guang et al. 2003, Gera et al. 1998). Fine roots are the source of nutrient uptake in a plant, thus, if a plant had more fine roots it should be more productive. Viewing the germination technique as a form of natural disturbance to the plant, this study measured the plant’s response in terms of productivity both belowground and aboveground. More shoots were produced by plants germinated in the ground in comparison to those germinated in bags (p < 0.05) indicate that the germination technique does affect aboveground productivity, though no affect was found on belowground productivity (p = 0.7055).

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  Elevation, habitat structure and Monteverde bird communities, November 2008

  Karl Fairchild

  One hypothesis for why “biodiversity begets biodiversity” when this pattern is observed in bird communities is that by increasing vegetative complexity finer niche partitioning is allowed for among bird species. Bird diversity has been shown to correlate positively with vegetation structure along a successional gradient. However, no such studies have been done in actively managed areas in the tropics. I used three 50 m fixed-radius point counts each in two pairs of study sites at different elevations to compare bird diversity in structurally simple and structurally complex pastures at two different elevations in Monteverde, Costa Rica. Within each pair, one site was simple and the other complex. I measured diversity within and across study sites using a variety of indices. I found that the total number of birds, species diversity, Margalef’s index, and the Shannon-Weiner index were all highest in the low elevation site with high structural complexity. These measures were lowest at the lower elevation site with low structural complexity, and intermediate at the two higher elevation sites, which showed no significant pattern. Additionally, I found that the two structurally complex sites were most similar in terms of diversity. This information lead me to conclude that vegetative structural complexity was a more important factor in determining bird diversity than altitude. This provides more evidence to support the “diversity begets diversity” hypothesis when one considers that structural diversity leads to increased resource diversity and feeding opportunities for bird populations.

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  Epiphyllic shading on host plant leaves: photo-acclimation to liverwort and lichen cover, November 2008

  Claire Addis

  Epiphylls are ubiquitous throughout the Tropics and may significantly shade their host leaves. Anthony et al. (2002) document increased levels of chlorophylls a and b in leaves with significant lichen coverage on two tropical understory plants in Australia, suggesting host leaves may respond to epiphyll shading by increasing photosynthetic pigments. Reaction of plants to the second major group of tropical epiphylls, liverworts, has not been studied. The purpose of this study was to see if a neotropical palm, Calyptrogyne gneisbregntiana, compensates for epiphyll cover by both lichens and liverworts. In addition to chlorophylls a and b, I investigate whether carotenoid levels also increase due to increased epiphyllic shading. The pigments of 80 understory leaf samples with either full lichen or full liverwort cover were extracted in acetone and analyzed using a spectrophotometer. It was found that only shading by lichens resulted in significantly higher chlorophylls a, b and carotenoids (mean = 142.95 ± 0.0350 ug/g, 62.4 ± 0.0178, and 77.5 ± 0.0188, respectively, P< 0.05) and per area for chlorophyll a and carotenoids (mean = 2.6 ± 0.0006 ug/cm2 and 1.45 ± 0.0003, respectively, P< 0.05). Ratios of chlorophyll a: b and total chlorophyll: carotenoids were not different between leaflets with 0% and 100% epiphyllic lichen or liverwort cover. These data show that C. gneisbregntiana compensate for lichen cover but not liverwort cover, and suggest that plants with epiphyllic lichens photo-acclimate to shading by increasing the concentration of light-harvesting pigments. The lack of significant increases in pigments seen in plants with liverwort cover may be due to habitat differences, where the plants may already be compensating to their full extent in response to environmental factors.

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  Impact of reward on floral mimics Lantana camara (Verbenaceae) and Epidendrum radicans (Orchidaceae), November 2008

  Kara Zwickey

  The fitness of a non-rewarding plant species can be increased by the addition of another plant species with similar flowers and reward present if pollinators are unable to distinguish between the two species (Bierzychudek 1981). Floral mimicry occurs between species when three ecological conditions are met: the model and mimic species must coexist within flight range of an individual pollinator, plant species must share pollinator species, and pollinator individuals visiting one plant must also visit one or both of the other plant species (Bierzychudek 1981). Non-rewarding Epidendrum radicans (Orchidaceae) has been shown to be a Batesian mimic of rewarding Lantana camara (Verbenaceae). Although mimicry increases the fitness of Batesian species when plants are in close proximity, mixed patches are widely spaced, and patch sizes are small (Deacon 2000; Woo 2001), there is little known about floral reward’s affect on the relationship. This study uses L. camara and E. radicans to test the impact of increased reward availability in model plants (L. camara) on pollinator visitation rates to both model and mimic plants. Two observation plots were constructed containing L. camara and E. radicans, where L. camara flowers in one plot were injected with a 20% sucrose solution. Plots were observed for butterfly visitation rates and monitored for pollinia removal from E. radicans. Increased reward in L. camara resulted in fewer visits to E. radicans flowers and L. camara inflorescences within the treated patch (three-way ANOVA: F = 24.0506; df = 1; P < .0001). In addition, L. camara inflorescences were visited longer with increased reward present (three-way ANOVA: F = 5.88; df = 1; P < .05). However, no difference was observed between pollinia removal between patches (Chi-square = 3; df = 1; P > .05). Different butterfly species had varying rates of visitation to the mimic species in response to an increased reward. Danaus plexippus visited 0.75 fewer E. radicans flowers, Leptophobia aripa visited 0.184 more flowers, and Anartia fatima visited 0.039 fewer E. radicans flowers (two-way ANOVA: F = 3.7887; df = 2; P < .05). As a result of increased reward, model and mimic species are negatively affected, due to a decrease in pollinator visitation rates. Prior research suggested rewarding flowers benefit most from being in close proximity to one another, in clumped patches (Deacon 2000). The results of this study suggest that L. camara may have been selected to produce a reward that favors a large number of visits to many flowers, which benefits the mimic as well. Although mimic flowers were visited, there was no affect on the pollinia removal from E. radicans, suggesting that patch size and density ultimately affect pollination rates of deceptive plants.

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  Interaction of color and sugar concentration preference with aggression in Monteverde Cloud Forest hummingbirds (Trochilidae), November 2008

  Laurel Anne Mundy

  In Monteverde, Costa Rica, a number of hummingbird species coexist that are extremely important for pollination. Hummingbirds may prefer flowers of a certain color because they associate it with a higher nectar reward. They also may be territorial and defend especially rich food sources, dominant birds driving away all subordinates. The purpose of this study was to investigate color and sugar concentration preference in hummingbirds using artificial feeders, and to determine whether dominance and aggression has an effect on food choice. Many hummingbird-pollinated flowers are red, so I hypothesized that all species would show a preference, and predicted that all would initially choose the red feeder of highest sugar concentration, eventually also choosing the two other high concentration feeders, realizing their equal reward. I also predicted that larger, male hummingbirds would dominate the food source more territorial, dominating the food source and forcing smaller birds to choose their second choice feeder. This was done by hanging six feeders of red, yellow and purple and high and low sugar concentration and recording species preference. I found that the Violet Sabrewing was the species that most often chose the red, high concentration feeder, as predicted (p=0.041669, df=2, x2= 6.356). No conclusions could be made about the three other species investigated as results were not significant. Preference was seen in the Violet Sabrewing, as differences in feeder preference decreased when only the last four days of data were analyzed, suggesting that color preference decreased. Most aggression was observed from the Violet Sabrewing (p=0.006019, df=9, x2=23.08). This species was clearly dominant likely due to its large size.

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  Presence of mucilage on aerial roots in Monteverde, Costa Rica, November 2008

  Chase Kincaid

  Many hemiepiphytes produce aerial roots and some have mucilage on the growing tips of these roots. The purpose of this study was to determine if mucilage varies at different altitudes in the Monteverde Cloud Forest in Costa Rica. Mucilage may serve to protect the roots from the dry environments, or from altitudes more prone to fungal infections since it has both high water storing capacities and anti-fungal properties. Transects were run along different altitudes, and samples of plants’ mucilage were taken, measuring the weight and length of the mucilage. Monstera was the most common plant with mucilage found in the study and was found at all altitudes ranging from 1,400 m to 1,800 m. There were a total of 12 Monstera plants, two Pitcairnia plants, and one Philodendron plant with a total of 34 mucilaginous roots. Twenty-three of the mucilaginous aerial roots were found on the genus Monstera (Araceae), 4 on Pitcairnia brittoniana (Bromeliaceae) and 7 on Philodendron (Araceae). No correlation was found between the weight and length of mucilage, compared to altitude of all three genera (Spearman rank correlation, N = 32; R2 = 0.135; p = 0.44 and N = 32; R2 = 0,86; p = .62, respectively). No correlation was also found for Monstera roots only, for weight and length compared to altitude (Spearman rank correlation, N = 23; R2 = 0.10; p = .12 and N = 23; R2 = .004; p = .759, respectively). A trend could be seen in the total mucilage frequency for low and high altitudes for Monstera. In this case, 16 Monstera were found at low altitudes, and seven at high altitudes, but this difference was not statistically significant (chi-squared test, x2 = 3.52, df = 1, p = 0.06). In conclusion, no altitudinal difference was found in mucilage size, suggesting genetic determinants might be playing a role, but twice as many Monstera were found at low altitudes compared to high altitudes, although further studies need to be done to clarify the trend.

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  Regulation of photosynthetic pigments in tropical understory and gaps, November 2008

  Maiken Westphal

  A plant can manipulate its absolute and relative amounts of photosynthetic pigments in different light environments (Hopkins, 1995, Goncalves and Vieira, 2001). Leaf samples from ten gap and ten understory plants were collected from Calyptrogyne brachystachys (Arecaceae), Heliconia monteverdensis (Heliconiaceae), and Piper ariteum (Piperaceae), and their chlorophylls a, b, and carotenoid concentrations were found. The total concentration of chlorophylls a, b, total chlorophyll and carotenoids were significantly higher (p = <0.05) in the understory leaf samples of C. brachystachys and P. auriteum, but higher in the gap samples of H. monteverdensis. Ratios of chlorophyll a to chlorophyll b were significantly greater for gap samples of all three species. A higher concentration of chlorophyll and carotenoids in the understory plants of C. brachystachys and P. auriteum suggests they are adjusting the absolute and relative amounts of pigments to make use of sparse light in the understory. H. monteverdensis utilizes its photosynthetic pigments slightly differently, acting much like a canopy plant.

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  Structure of soil arthropod and plant communities in light gaps and continuous forest in Monteverde, Costa Rica, November 2008

  Lauren Breza

  Several studies have confirmed that higher plant community richness facilitates greater arthropod community richness. The purpose of this study is to examine how plant community structure in continuous forest and light gaps impact soil arthropod community structure. In this study plant surveys were conducted for twenty plots, ten located in continuous forest and ten located within a forest gap. Along with plant surveys, a soil sample from each plot was collected in order to obtain soil dwelling arthropods. Arthropods were extracted from the soil first using a Burlese funnel, and then manually picked out of the soil. After all arthropods were obtained, they were identified to order and when possible to family. It was hypothesized that there would be a correlation between plant community structure and soil arthropod community structure, as well as a difference in diversity in continuous forest and forest gaps. The richness, evenness, and Smarg were calculated for plants in closed forest and in forest gap (H1' = 2.892, H2' = 2.406, t = 4.72, p < 0.0005). In addition, the richness, evenness and Smarg were calculated for soil arthropods in closed forest and in forest gap (H1' = 2.052, H2'= 1.896, t = 1.44, p = 0.10). There was no difference between soil arthropod diversity in continuous forest and forest gap and plant diversity did vary between continuous forest and forest gap. Regression analyses were also conducted, and the results suggest that there is no correlation between plant and soil arthropod community composition. However, there were obvious trends derived from the regressions that should be taken into consideration for future studies.

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  The effect of hummingbird feeders on the pollen loads and diversity in nectarivorous bats (Glossophaginae) in a tropical cloud forest, November 2008

  Benjamin Juan Padilla

  Bats are some of the most important pollinators in tropical regions. I studied the effect of hummingbird feeders on pollen loads in nectarivorous bats in the Monteverde region. I mist netted bats at two locations Selvatura Hummingbird Garden (deemed high feeder density), and the Santa Elena Reserve (low feeder density). Pollen was removed from the bat’s back using clear scotch tape and placed directly onto microscope slides for examination. A Shannon-Weiner diversity index showed that there was a difference between the pollen diversities (Selvatura H’=5.47, Reserve H’= 4.63) although mean pollen diversity and overall pollen count were not different. These differences could have been attributed to the fact that Anoura geoffroyi was the main species caught at the Reserve while Glossophaga spp. was caught at Selvatura.

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  The effect of reward and color pattern on butterfly foraging in Lantana camara (Verbenaceae), November 2008

  Jenna Short and Tara Florida

  Lantana camara has inflorescences composed of young, nectar-producing yellow flowers surrounded by older orange flowers that no longer produce nectar (Moldenke 1973). We examined the relationship between L. camara and its butterfly pollinators to see if the preference for yellow flowers (Peters 1998) is innate or learned. Further, we altered the position of flower color on the inflorescence to see if the normal yellow-centered bull’s eye pattern increased visitation over other patterns. We collected data for butterflies foraging on L. camara with six patterns of yellow and orange flowers by painted these colors on the inflorescences. Next, we watched these same patterns with a 20% sucrose solution injected to all of the flowers on an inflorescence. Butterflies demonstrated an innate preference for yellow flowers as an addition of nectar to orange flowers showed no change in preference. Likewise, butterflies showed a preference for yellow flowers in all cases (df = 1, x2 = 4.734, p = 0.02). Varying the pattern of yellow and orange flowers in an inflorescence showed that butterflies prefer a solid yellow inflorescence. Therefore, it appears that the pattern of flower color and butterfly preference have not coevolved to enhance visitation and hence, pollination. While butterflies benefit from innately visiting yellow flowers most frequently, L. camara may increase pollinator visits by keeping its older flowers yellow in order to create a solid yellow inflorescence.

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  The effects of intrinsic and extrensic factors on floral visitation of Xanthosoma undipes in Monteverde, Costa Rica, November 2008

  Kirsten Martin

  Both intrinsic and extrinsic floral characteristics exert important influences on floral visitation. The average distance between flowering plants, the number of flowering plants, and the spadix temperature were assessed to determine the influence of these intrinsic and extrinsic floral factors on floral visitation in Xanthosoma undipes in Monteverde Costa Rica. Observations were made for seven nights in which the distances between all flowering plants, abundances of all morphospecies of arthropods present and spadix temperatures were taken. Both the number of plants in flower and the average distance between flowers did appear to have an affect on flower visitation among pollinators. As the number of male inflorescences open in a night increased, the number of scarabs per inflorescence tended to decrease (p = 0.0687). It was also found that as the average distance between plants increased, the number of scarabs per inflorescence increased (p = 0.0374). On the other hand, arthropod abundances showed no correlation with either the number of plants in flower (p = 0.1911) or the average distance between flowering plants (p=0.1881), which suggests a lower degree of specialization among interlopers than the Cyclocephala pollinators. The inflorescences sexual identity, an intrinsic factor, did have an affect on visitor composition. Diversity in male inflorescences was significantly higher than diversity in female inflorescences (H’males=1.5097, H’females=0.6466. t= 15.826, F = 1.964). This study showed that both intrinsic and extrinsic factors are important in floral visitation in X. undipes, and different floral factors have differing affects on interloper and scarab visitation. Understanding the effects of both intrinsic and extrinsic factors in floral visitation is important because plant pollination directly affects plant reproduction and therefore directly affects plant fitness.

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  Water use, wastewater disposal, and water conservation attitudes in the Monteverde zone, November 2008

  Jenna Rasmusson

  The residents of the zone of Monteverde, Costa Rica represent a wide array of demographics and other factors such as income, education level, town of residence, and water source, which may impact their water use, wastewater disposal, and water conservation attitudes. In order to study these relationships, a survey was conducted in four different Monteverde towns. The survey consisted of questions on demographic variables, water consumption patterns, methods of disposal, and water shortages, and lastly, addressed attitudes toward water conservation. Data were collected from 64 surveys and analyzed using regression analyses and chi-squared tests. Thirteen significant results and several trends were found. Income, education level, and location of residence played a significant role in several response variables such as water source protection and perceived water problems in Monteverde. The most significant trend, perhaps, came from Monteverde residents whose water comes from streams. This group of people was significantly unsatisfied with quality, quantity, and water source protection. They also perceived significant water problems in Monteverde and believed that the federal government was the responsible party for making needed improvements. Several people interviewed whose water is from streams were concerned with the health effects from these unprotected water sources, indicating a need for future studies.

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  Within-crown asynchrony of Ficus pertusa (Moraceae), November 2008

  Hannah Lippe

  Well-supported theory says that populations of Ficus species reproduce asynchronously across populations and synchronously within individual trees. However, recent studies in the Monteverde area have found evidence for within-crown asynchrony for Ficus tuerckheimii, a large strangler fig, and hinted at within-crown asynchrony for Ficus pertusa, a small free-standing tree. I tested the prediction that fig tree populations are asynchronous and individuals are synchronous by looking at fifteen F. pertusa trees with fruits. I looked for microclimate effects on flowering synchrony as a result of uneven sun exposure within a crown. As predicted, the population was asynchronous, but 13 out of the 15 trees displayed within-crown asynchrony. The interval distance between successive development stages was never greater than two, showing that asynchrony is slight. No consistent trends were found across positions, indicating that sun exposure may not create a differential in syconia development. Microclimate effects did not influence asynchrony, suggesting that within-crown asynchrony, a supposed anomaly, could be an adaptive consequence of other physiological or ecological factors.

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  Pollinator efficiency in Blakea gracilis (Melastomataceae), October 2008

  Sullivan Peraino

  Blakea gracilis (Melastomataceae) is one of 20,000 species of flowering plants whose flowers have poricidal anthers. This morphology is adapted for “buzz-pollination,” where bee-induced vibrations result in the expulsion of pollen through the anther pores. The frequency of vibrations significantly affects pollen release, with peak anther discharge occurring at 500 Hz. Bees, however, are only able to buzz at about 300 Hz, and rarely reach frequencies higher than 400 Hz. This gap leaves the potential for a “most efficient” pollinator, a particular bee able to buzz at the highest frequency, thereby procuring the most pollen per visit and moving more pollen from flower to flower. In this study, I aimed to determine whether a “most efficient” pollinator exists for Blakea gracilis. I focused on large-bodied bees and small-bodied bees, predicting that larger bees would be capable of reaching higher frequencies and therefore would be better pollinators than their smaller counterparts. I found that large- and small-bodied bees open the same number of anthers per visit (t = 0.553, df = 36.277, p = 0.584), even though small bees spend significantly more time buzzing each flower (t = 3.753, df = 22.5, p = 0.001). Large-bodied bees achieved the same success as their smaller counterparts in less time by opening more anthers per second (t = -3.266, df = 36.3, p = 0.002). Despite their length of visitation, the amount of time each size-class spent buzzing a flower did not affect how many anthers they opened (large-bodied: R2 = 0.061, p = 0.080, t = 1.786; small-bodied: R2 = 0.169, p = 0.057, t = 2.019). I found one exception in Bombus sp., which was able to open more anthers the longer it vibrated the flower (Spearman’s Rho = 0.576, p = 0.041, N = 10). I found that there is no “most efficient” pollinator of Blakea gracilis, instead the results are consistent with those of past studies which concluded that buzz-pollination is generalized to all bee visitors.

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  Activity patterns of damselflies and dragonflies (Odonata) in Monteverde, Costa Rica, August 2008

  Jenny Gaynor

  Daily periods of activity tend to vary across different species of dragonflies and damselflies of the order Odonata. The purpose of this study was to investigate the activity patterns of five different behaviors for five different species of odonates. Observations were made at the Estación Biológica de Monteverde over a weeklong period in late July. Results showed that there were variations in behavior compared with time both within and across the five species. However, each species did not display every behavior, and behaviors were not evenly distributed across different species. This may be a result of variance in population sizes or that observations were not conducted at peak times of activity for certain species.

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  Aggregational behavior and nest ownership of Crawfodapis luctuosa (Diphaglossinae: Apidae), August 2008

  Nathan J. Spaht

  Crawfordapis luctuosa is a large, black, diurnal bee found in aggregations on exposed clay sites above 1500m in elevation from the highlands of Mexico to Panama. Many past studies have attempted to classify the exact sociality and nest ownership of this species; this study follows their examples in an attempt to better define these behaviors. Data was gathered on nest usage, visitation behavior as well as aggressive and non-aggressive interactions. This study reaches no definite conclusions as to the patterns of nest ownership in the five days of observation. Individuals consistently visited more than one nest and up to seven different nests. These multiple visits are likely searches for abandoned nests or new nests if previous nests have been stolen by Pseudoxycheila tarsalis or other members of the colony. Instances of two bees inhabiting the same nest simultaneously were observed and concluded to demonstrate a degree of cooperation, though some interactions ended violently. This study has concluded that C. luctuosa is a mostly solitary bee and that interactions between individuals are mostly random, and although there is evidence of both cooperation and competition within the colony, it is limited.

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  Bird diversity in fragmented forests in Monteverde, Costa Rica, August 2008

  Heather Hulton

  Due to deforestation, fragmented forests and secondary growth are replacing old growth forests. These fragments are reduced in biodiversity. In this study, bird diversity of a pre-montane forest fragment, Bajo del Tigre, connected to the Monteverde Reserve through a corridor, and plus two other fragmented forests, Calandria and House Fragment, in Monteverde, Costa Rica were compared. It was expected that the fragment with the highest degree of protection and is connected to the Monteverde Cloud Forest Reserve should have a higher bird diversity. There is a difference between Bajo del Tigre and the two forest fragments in bird diversity when the Shannon-Weiner diversity index is calculated between Bajo del Tigre (H’ = 2.78) and Calandria (H’ = 2.04) (Modified t-test, t = 7.39, p = <0.001) along with Bajo del Tigre and House Fragment (H’ = 2.15) (Modified t-test, t = 5.52, p = <0.001).

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  Changes in wormlion (Vermilionidae) pit construction in response to energy inputs and disturbances, August 2008

  Luke Hillman

  Wormlions are insects that, like antlions, are sit and wait predators in their larval stages, for whom optimizing energy expenditures is crucial because of potentially long periods of starvation. Initial pit depth and pit growth rates of antlions have been shown to decrease in response to limited food resources. Due to the similar foraging technique of worm and antlions, wormlions were hypothesized to show similar responses. Thirty-two wormlions were randomly divided into four treatments: fed-disturbed (FD), fed-undisturbed (FU), unfed-disturbed (UD) or unfed-undisturbed (UU). An aphid was dropped into wormlion pits of the FU and FD treatments, and pits in “disturbed” treatments were overturned daily. Pit volume was calculated daily from pit measurements, plotted against time and analyzed with regression equations. No statistical difference in pit growth rates (t14 = 0.939, p = .364) or elevation (t 15 = .0487, p = 0.962) was reported between fed and unfed treatments. By extrapolating pit volumes of the FU and UU treatments, the optimum pit volume was estimated to be 5.92 cm3. Although not significant, a decrease in initial pit volume appeared to exist for unfed wormlions (t17 = 1.848, p = 0.082). The data suggest that wormlions have more efficient pit construction adaptations in response to shorter larval development and limited predation opportunities.

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  Distribution and abundance of Prosapia (Homoptera: Cercopidae) in Monteverde-area farms, August 2008

  Ryan Brower

  Prosapia spp. commonly known as spittle bugs, froghoppers, or “la Prosapia”, are pasture pests for dairy farmers in the Monteverde region of Costa Rica. The adults eat pasture grass, disturb plant growth, as well as reduce nutritional and palatability values of the pasture grass for dairy cattle, and are responsible “froghopper burn”. This study examined the relationship between altitude and Prosapia abundance in cattle pastures of farms surrounding Monteverde in Costa Rica. It was hypothesized that abundance will differ with altitude. A total of 11 farms in the Monteverde region of Costa Rica ranging from 825 m to 1510 m in elevation were surveyed between July 18, 2008 and July 30, 2008. At each farm, the owners were questioned about the number of cows, hectares of pasture grass, days of grazing before rotating cows, use of pesticides, chopping and/or burning of grass, and type of pasture grass. Prosapia adults and nymphs were counted by hand within three randomly chosen 1 m2 plots of pasture grass of the same farm and the grass was identified as either “burned” or “not burned”. “Burned” pastures were almost completely yellow and dying; while “not burned” pastures were almost completely green. A significant difference in Prosapia abundance was found between “burned” and “not burned” pastures with a higher average abundance of Prosapia in the “burned” pastures. A significant difference in the average altitude of“burned” and “not burned” pastures was found, with “burned” pastures having a higher average altitude. Overall, while no significant trend was found between abundance and altitude, the data strongly suggest that Prosapia abundance increases with altitude.

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  Distribution of American Leaf Spot disease (Mycena citricolor) in coffee plantations in Cañitas, Costa Rica, August 2008

  Caitlin Looby

  One of the biggest commodities in the world coffee (Coffea) is an extremely important crop to Costa Rica. There are many ways to manage this crop, however it is primarily shade-grown. Although it is the best method in which to conserve biodiversity, these conditions also promote the growth of Mycena citricolor. Also, known as American Leaf Spot disease, this fungal pathogen causes coffee plants to defoliate and lose their fruit. Four farms in Cañitas, Costa Rica were visited and 12 plants per farm were studied to determine the distribution of this fungus during the wet season. This study also compares the abundance of M. citricolor in the wet and to a previous study of the dry season. To do this, the number of spots on the leaves of each of 12 plants was counted. It was determined through an Index of Dispersion test that each plot possessed an aggregated distribution (p < 0.001). When a Kolmogorov-Smirnov test was performed, every farm showed a significant difference in the abundance of spots (p < 0.005) in the wet and the dry seasons.

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  Diversity and morphological variation in Formicidae in three strata of the Monteverde Cloud Forest, August 2008

  Peter A. Larson

  This study examines the arboreal presence of ants. Comparisons of diversity at three forest strata, canopy, mid-level, and forest floor were analyzed. Measurements were also made of leg length to body length and compared across the strata. The hypothesis is that arboreal ants will have a higher leg to body ratio. Finally a representation of each ant species, except three under-represented species was dropped from the canopy to test for the ability to “glide”. Conclusive results showed that ant diversity is greatest at the mid-stratum (H’ = 1.82). The remaining two strata, canopy and floor, showed similar diversity values (H’ = 1.04 and .86 respectively). Significance was found between mid-level and forest floor, and mid-level and canopy (p < 0.05). Canopy level and mid level ants showed no difference in body length, leg length, or the ratio between the two (p > 0.05). Both, however, showed larger values than the forest floor ants in all three cases (p < 0.05). None of the ants glided or showed any signs of being able to. Further study is required to solidify these results but it seems evident that both greater diversity and a necessity for longer legs are consistent in arboreal ants.

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  Epiphyte communities in Cupressus lusitanica windbreaks and Myrsine coriacea, Monteverde, Costa Rica, August 2008

  Casey Halstead

  Monteverde, Costa Rica is home to a quintessential lower montane cloud forest that supports an amazing diversity of epiphytes. Windbreaks comprised of the exotic Cupressus lusitanica are common surrounding deforested areas. C. lusitanica appears to be poor epiphyte habitat when compared to a native species Myrsine coriacea. This survey was conducted using species richness and occurrence data collected using transparent acetates. This survey examines the idea that C. lusitanica supports reduced epiphyte diversity. The survey determined that the apparent difference in epiphyte richness and community composition is significant. ANCOVA analysis revealed several negative correlations for M. coriacea but not C. lusitanica. Lichen and moss abundance were affected by each others abundance as well as by CBH.

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  Family richness and diversity of vascular epiphytes and climbers in the canopy of a lower montane wet forest, Costa Rica, August 2008

  Jennifer D. Savidge

  Many studies have been done regarding vascular epiphyte communities in the tropics, however all of the previous studies have neglected the canopy branch tips due to their limited accessibility (Nieder et al. 2004, Freiberg and Freiberg 2000, Zotz et al. 1999, Hietz 1997, Freiberg 1996, Ingram and Nadkarni 1993). The purpose of this study was to evaluate differences in family richness, and diversity of previously unstudied branch tip epiphyte communities vs. those of secondary branch bases. Data were gathered about community composition of vascular epiphyte families and climbers on the branch tips of canopy trees in a Neotropical, lower montane rainforest in Costa Rica. Branches were accessed from suspension bridges ranging from 32-65 m, in Selvatura Park, Costa Rica. The number of individuals from each family and total branch area covered by each family were recorded. Branch tip and base communities were compared using S, H’, E, N, and Smarg parameters (Magurran 1988), and diversity indices were compared using a t-test. Additionally a pair-wise comparison was carried out on each branch base and tip pair using a sign test (Ambrose et al. 2002). Counts of number of individuals per family were deemed to be inaccurate due to the difficulty in identifying individual ferns. As such, coverage area data were used to draw conclusions. Branch tips (H’ = 0.27) were found to have a significantly higher diversity than branch bases (H’ = 0.71) (p-value < 0.001). However, branch bases were found to have a significantly higher family richness even when differences in abundance were controlled for. It was noted that almost all branches surveyed showed high dominance of the Division Pteridophyta on both branch bases and tips. Future studies of epiphyte communities in canopy branch tips should address the issue of identifying individual ferns when root systems are covered in humus and bryophyte mats, as was observed in this study.

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  Kin recognition in the social spiders Anelosimus sp. in Monteverde, Costa Rica, August 2008

  Mary Kathryn Busby

  Anelosimus spiders are social and use pheromonal and vibrational cues to distinguish conspecifics from predators and prey. Juveniles live in their natal web with adults until maturity, at which time they disperse. Given that juveniles are more likely to disperse to locations near to their natal web and that Anelosimus has developed mechanisms for kin recognition, these spiders would be expected to exhibit aggressive behavior less frequently in the presence of intruding spiders from nearby webs than towards intruders from distant webs. This hypothesis was tested by introducing spiders to new webs from distant locations as well as from nearby locations. There was no significant relationship found between web distance and level of aggression (C2 = 5.47, df = 2, p = 0.06) nor between colony size and level of aggression (C2 = 2.43, df = 2, p = 0.30). A linear regression comparing colony size to level of aggression yielded no significant results for ignoring behavior (F = 0.94, df =1 and 18, p = 0.34), approaching behavior (F = 3.36, df = 1 and 18, p = 0.08), nor aggressive behavior (F = 0.29, df = 1, p = 0.59). According to this data there is little indication that spiders change their level of aggression due to colony size or distance between webs. This study provides data that can be used to explain the purpose and function of kin-recognition behaviors.