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Anlisis observacional de la diversidad de insectos, la riqueza y la abundancia de los hongos, Auricularia delicata (Basiodiomycata)
Observational analysis of insect diversity, richness, and abundance on the fungus, Auricularia delicata (Basiodiomycata)
Fungi are important to ecosystems because of their ability to release nutrients back into the environment and their relationships with insects. This study determined the diversity and richness of insects attracted to
Auricularia delicata and related it to external conditions. Eleven colonies of Auricularia delicata were located near the Estacin Biolgica de Monteverde and observed to determine the morphospecies and abundance of insects present. The results illustrated that insect abundance significantly increased with species diversity (RS = 0.778, P = 0.0001.) Insect abundance significantly increased with colony surface area (RS = 0.659, P = 0.0371) and number of fruiting bodies present in a colony (RS = 0.487, P = 0.0171). Morphospecies richness significantly increased with surface area (RS= 0.693, P=0.0284), and with insect density (RS = 0.802, P < 0.0001). Diversity was compared to surface area and total number of fruiting bodies but was not found to be significant affected by either. This study indicates that important interactions take place between insects and Auricularia delicata.
Los hongos son importantes para los ecosistemas debido a su habilidad para liberar nutrientes de nuevo en el medioambiente y a sus relaciones con los insectos. Este estudio determin la diversidad y la riqueza de los insectos atrados por Auricularia delicata y se relacion con las condiciones externas. Once colonias de Auricularia delicata se localizaron cerca de la Estacin biolgica de Monteverde y fueron observadas para determinar las morfoespecies y la abundancia de los insectos presentes. Los resultados ilustran que la abundancia de los insectos aument significativamente con la diversidad de especies (RS = 0.778, P = 0.0001). Tambin se encontr que la abundancia de insectos increment significativamente con el rea de la superficie de la colonia (RS = 0.693, P = 0.0371) y con el nmero de cuerpos fructferos presentes en la colonia (RS = 0.487, P = 0.017). La riqueza de morfoespecies increment significativamente con el rea de la superficie (RS = 0.693, P = 0.0284) con respecto a la diversidad de especies (RS = 0.802, P < 0.0001). La diversidad estuvo relacionada con el rea de la superficie y con el total de cuerpos fructferos y se encontr que no es significativa. Este estudio indica que hay interacciones importantes que se dan entre insectos y Auricularia delicata.
Text in English.
Monteverde Biological Station (Costa Rica)
Diversidad de especies
Estacin Biolgica de Monteverde (Costa Rica)
Tropical Ecology Summer 2004
Ecologa Tropical Verano 2004
t Monteverde Institute : Tropical Ecology
Observational Analysis of Insect Diversity, Richness, and Abundance on the fungus, Auricularia delicata (Basiodiomycata) Megan Scott Department of Biology, James Madison University ABSTRACT Fungi are important to ecosystems because of their ability to release nutrients back into the environment and their relationships with insects. This study determined the diversity and richness of insects attracted to Auricularia delicata and related it to external conditions. Eleven colonies of Auricularia delicata w ere located near the Estacin Biolgica de Monteverde and observed to determine the morphospecies and abundance of insects present. The results illustrated that insect abundance significantly increased with species diversity (R S = 0.778, P = 0.0001.) Insec t abundance significantly increased with colony surface area (R S = 0.659, P = 0.0371) and number of fruiting bodies present in a colony (R S = 0.487, P = 0.0171). Morphospecies richness significantly increased with surface area (R S = 0.693, P=0.0284), and wi th insect density (R S = 0.802, P < 0.0001). Diversity was compared to surface area and total number of fruiting bodies but was not found to be significant affected by either. This study indicates that important interactions take place between insects and Auricularia delicata RESUMEN Los hongos son importantes para los ecosistemas debido a su habilidad para liberar nutrimentos de vuelta en el ambiente y a sus relaciones con los insectos. Este estudio determin que la diversidad y riqueza de insec tos atrados a Auricularia delicata y relacion esto a condiciones externas. Once colonias de Auricularia delicata se localizaron cerca de la Estacin biolgica de Monteverde y fueron observadas para determinar las morfoespecies y abundancia de insectos p resentes. Los resultados ilustran que la abundancia de insectos aument significativamente con la diversidad de especies (R S = 0.778, P = 0.0001). Tambin se encontr que la abundancia de insectos increment significativamente con el rea de la superfici e de la colonia (R S = 0.693, P = 0.0371) y con el nmero de cuerpos fructferos presentes en la colonia (R S = 0.487, P = 0.017). La riqueza de morfoespecies increment significativamente con el rea de la superficie (R S = 0.693, P = 0.0284) con respecto a la diversidad de especies (R S = 0.802, P < 0.0001). La diversidad estuvo relacionada con el rea de la superficie y con el total de cuerpos fructferos y se encontr que no es significativa. Este estudio indica que hay interacciones importantes que se d an entre insectos y Auricularia delicata INTRODUCTION Approximately 72,000 species of fungi have been described, out of a possible 1.5 to 9.9 million species total (Gilbert and Sousa 2002.) With so many undescribed fungi, and limited knowledge about ma ny of the species, studies are needed to further our understanding of this important group of organisms. The cycling of nutrients is very important in the tropics because nutrients follow strict pathways in order to be quickly reintroduced into the ecosys tem (Mata 1999). Some fungi provide plants with nitrogen directly but most fungi are decomposers, essential in making nutrients available to other organisms. They ensure that leaf litter, fallen limbs, and even man made objects such as leather, cloth, plas tic, and rubber do not build up
(Mata1999.) Besides these processes, fungi interact with other organisms, namely insects. It is known that several families of insects feed on fungi (Daly et al. 1998.) Insects are also extremely important medically, economi cally, and ecologically (Zumbado 1999.) Without fungi to supply nutrients and their interactions with insects, our world could not exist. However, with not much known about fungi, they could be ignored when political, economic or ecological decisions are m ade, which would not only upset nutrient cycles, but also food webs and even biomes. Fungi are categorized into four different groups, based on reproductive structures. Basiodiomycata are characterized by microscopic structures called basidia that produce the spores, mostly in groups of fours, outside the basidia structure. Within Basidiomycata, there is the order Auriculariales. This order has 6 families with 30 genera (Alexopoulos et al 1996) including the family Auriculariaceae and the species Auricular ia delicata. A. delicata are glutinous mushrooms generally 2.0 6.5 cm wide and 0.5 4.5 cm long, exhibiting a light brown upper side and a net like underside that is an identifying characteristic of this species (Mata 1999.) This species is edible, and the re is evidence that larva of Decameria (Hymenoptera) feed on it (Hanson & Gauld 2000.) It is not known if other insect species are attracted to A. delicata or the nature of these interactions. Preliminary observations indicated that a wide range of insec ts would be attracted to A. delicata The objective of this study was to observe A. delicata and determine the morphospecies richness and diversity of insects that visit it. Relationships between insect abundance, morphospecies richness, colony surface are a, number of fruiting bodies present in a colony, time of day and weather conditions were determined. MATERIALS AND METHODS The study site was conducted in the forest near the Estacin Biolgica de Monteverde, Monteverde, Costa Rica. The study was cond ucted between June 18, 2004 and August 8, 2004. Eleven colonies of A. delicata were located within the altitude range of 1510 to 1555 meters. A colony of A. delicata was defined as any number of fruiting bodies located on a single substrate. Most colonies were located close to the Quebrada Maquina, and found on a variety of wooden substrates including fallen branches, rotting stumps, fallen trees, and cut logs. Colonies were observed to record the number of morphospecies and abundance of insects located on the fungi. Insects were identified to morphospecies by physical characteristics. Colony observations were taken in two intervals of fifteen minutes. Observations were taken on different days to vary environmental conditions and time of day. Weather was c ategorized into three divisions: sunny with some cloud cover, overcast and raining conditions. No more than one observation at a particular colony was taken per day. Times of day were categorized into morning (5:25 am 12 pm), afternoon (12 pm 3:45 pm) and evening (3:45 pm 5:30 pm). Twenty five total observations were taken, amounting to 12.5 hours, each colony had 2 3 observations, with the range of individual fruiting bodies (2 20) observed per observation. Shannon to compare insect diversity between colonies. Effects of weather and times of day were determined using Kruskal
Wallis tests. Spearman rank correlations determined significance between morphospecies, insect abundance, surface area, total number of fruiting bodies, and density of insects per fruiting body. Simple bivariate regressions illustrated the variables tested with Spearman rank correlations. Histograms were used to show the distribution of he difference between times of day. RESULTS A total of 80 morphospecies were identified. The abundance of each morphospecies ranged from 1 62 individuals (average of six, standard deviation of 12.15). Each colony contained a range of 2 23 morphospecies (average 11, standard deviation of 7.14) and a range of 2 162 individuals. For each half hour observation period, 0 17 insect morphospecies were observed (average of 5, standard deviation of 4), while 0 84 individuals were observed per observation. The nu mber of morphospecies was significantly positively correlated with number of insects R S =0.778, P=0.0001 (Figure 1). The number of insects was also significantly positively correlated with the number fruiting bodies R S = 0.487, P=0.0171 (Figure 2). Number of individuals increased with increasing surface area R S ==0.659, P=0.0371(Figure 3). A similar trend occurred with surface area and species richness, R S =0.693, P=0.0284 (Figure 4). The number of insect species increased significantly in relation to the densi ty of insects per fruiting bodies R S =0.802, P<0.0001(Figure 5). Density of insects per fruiting bodies was not statistically significant related to colony surface area. 1.048 (col value = 2.369, P = 0.02) (Table 2) (t value = 6.248, P <0.0001). Site one had a significantly value = 14.954, P < 0.0001). value = 4.362, P < 0.0001). Weather and time of day were not found to be statistically significant in regards to insect abundance, species diversity o r insect density. Species abundance was very similar for morning and afternoon. DISCUSSION This study found that as insect abundance on A. delicata increased, the higher the morphospecies diversity became. There was a very strong trend for morphospecies richness to increase with density of insects per fruiting body. It was also found that total number of fruiting bodies directly affects morphospecies richness and insect abundance. The ranges show that there was wide variance between the abundance of morp hospecies and the numbers recorded per colony. The positive trends of abundance when compared to surface area and total number of fruiting bodies and diversity to
surface area were interesting. If the insects have a negative affect on the fungi, it would b e in best interest to not grow in large colonies or on large substrate. Therefore, insects could be positive for the fungi, perhaps being a spore disperser. However, colonies were noted to contain larvae within the colony, with the larvae bel ieved to be eating through the fungi. It was also noted that flies extended a white body part in the vicinity of their mouth and poked at the fungi at top and underside. This indicates the insects could have a negative affect on the fungi, but perhaps the benefits of the insects were greater than the cost. There was a strong trend to have diversity of species increase with density of insects per fruiting body. Certain flies displayed by flapping their wings and moving towards other flies, believed to be a t erritorial behavior. However, this could lower abundance of certain morphospecies that limit diversity, allowing more morphospecies to be present. It was found that some colonies, especially after rains, would lose some individuals. Before some fungi fell off the site, for an unknown reason, they became gelatinous and changed to a darker color or became more translucent which could be a sign of natural aging. A study could be done to determine the lifespan of colonies and what it is dependent on. In contra st, certain sites contained a high proportion of dried up done to quantify the health of colonies and relate it to insect diversity and abundance. Colony health could b e related to humidity and insects may be observed to prefer A study using insect traps to determine if insects visit A. delicata at night would be interesting. It has been proven that different morphospecies are act ive during the night (Rosenthal, 2004). Although the diversity and richness of insects has been found, there are no studies that investigate how they are interacting with the fungi. The mechanism of spore dispersal must be investigated, as from the observa tions taken insects seem to prefer the bottom of the fruiting body, where the spores are located, over the top. This study indicates that there are strong interactions between insects and A. delicata and external factors affect insect presence. Insect pr esence affect other organisms nearby and affect the overall food web if that region. ACKNOWLEDGEMENTS I would like to thank the Estacin Biolgica de Monteverde for supplying forest and resources for me to carry out my experiment. Carlos, my hero, for always having patience with me. Carmen, gracias por su espaol. Thank you Maria and Ollie for their wonderful grammar and statistic skills and always listening to me. Thanks to the Alvarado Snchez family for taking me in and being wonderful and my real fa mily back at home for supporting me and loving me, no matter what. Lastly, thanks to all the students in CIEE summer Costa Rica 2004 for making my time here delightful and memorable. LITERATURE CITED Alexopoulos C. J, C. W. Mims, and M. Blackwell. 1996 Introductory mycology. Fourth Edition. Pg. 663. John Wiley & Sons, Inc., New York, USA.
Borror D., C. Triplehorn, & N. Johnson. 1992. An introduction to study of insects. Sixth Edition. pg. 753. Harcourt Brace College Publishers, Orlando, Florida. Daly H.V, Doyen J.T, Purcell A.H. 1998. Introduction to insect biology and diversity Second edition. Oxford University Press, New York, New York. Gilbert G., W. Sousa. 2002. Host specialization among wood decay polypore fungi in a caribbean mangrove for est. Biotropica. 34:396 404. Hanson P., I. Gauld. 2000. Hymenoptera: sawflies, wasps, ants, and bees. In N. NADKARNI & N. Wheelwright (Ed). Monteverde ecology and conservation of a tropical cloud forest, pg. 124 129. Oxford University Press, New York, N ew York. Mata, M. 1999. Macrohongos de costa rica mushrooms Vol. 1. Instituto Nacional de Biodiversidad. Zumbado M. 1999. Dpteros de costa rica diptera. Instituto Nacional de Biodiversidad. Figure 1: Positive relationship between the number of morphospecies of insects on 11 colonies of A. delicata and the number of individuals during 25 observations (R S = 0.778, P = O.000) (Monteverde, Costa Rica)
Figure 2: Positive relationship between number of fruiting bodies and number of insects on 11 colonies of A. delicata in Monteverde, Costa Rica (R S =0.487, P= 0.0171) Figure 3: Positive correlation between surface area and number of insects on 11 colonies of A. delicata in Monteverde, Costa Rica (R S = 0.659, P= 0.0371)
Figure 4: Posi tive correlation between surface area and number of species on 11 colonies of A. delicata in Monteverde, Costa Rica (R S = 0.693, P= 0.0284) Figure 5:Positive correlation between density (insects per fruiting bodies) and number of species taken fro m 25 observations and 11 colonies of A. delicata in Monteverde, Costa Rica (R S = 0.802, P <0.0001)
Table 1:Shannon Weiner indices of diversity calculated for 11 colonies of A. delicata in Table 2: Unpaired t test used to co significant difference between diversity of the colonies of A. delicata in Monteverde, Costa Rica comparisons t value variance significance site 11 & 12 2.369 162 0.02 site 9& 10 1.723 52.863 X site 7& 8 1.116 29.271 X site 4& 5 0.516 102.967 X site 2 &3 2.134 133.079 0.05 site 7& 11 0.512 26.11 X site 1& 11 14.954 162 <.001 site 4 & 7 4.362 11.812 <.001 Colony H' site 1 0.301 site 2 1.042 site 3 0.852 site 4 1.048 site 5 1.003 site 7 0.735 site 8 0.628 site 9 0.719 site 10 0.493 site 11 0.774 site 12 0.699 Avg 0.754