! Zombie Fungi: O ccurrence of Arthropod E ndoparasitic Fungi at Different Altitudes in the Monteverde Region Madeline Sandler Department of Environmental Studies and Sustainability University of California, Santa Cruz EAP Tropical Biology and Conservation Program, Fall 2016 16 December 2016 ABSTRACT Arthropod e ndoparasitic fungi consist of multiple genera that exploit the bodies o f insects and arachnids as host organisms to spread their fungal spores and to obtain nutrients from the body of the host Arthropod parasitic fungi can be classified into three families : Clavicipitaceae, Cor dy ipitacea e and Ophiocordycipitacea e I conducted an observational study in the Monteverde region of Costa Rica where I collected and analyzed arthropods that have been parasitiz ed with fungi by searching in different altitudes and life zones My goal was to deter mine if there was an altitudinal gradient associated with the presence and abundance of arthropod parasitic fungi and which Orders were most affected. The result s reveal that there is the highest abundance of parasitized arthropods at the lowest altitude and the least abundance at the highest sampled altitude. However, there is no trend in abundance in increasing altitudes. I found the highest abundance of arthrop od hosts present in the Order Hymenoptera in various wasp species There is variety in fungal morphologies between nearly every individual I found that range from mold looking to mushroom fruiting bodies. T his paper provides detailed description s of every sample of parasitized arthropod the specific microhabitat it was discovered in and the method of attachment it has taken to the substrate. These detailed descriptions reveal the high variation in which fungal parasites can attack arthropod host s in a range of ecosystems. Hongos zombies: ocurrencia de Hongos EndoparasÂ’ticos de ArtrÂ—podos en diferentes zonas de la regiÂ—n de Monteverde RESUMEN Los hongos endoparasiticos de artrÂ—podos es un grupo de mÂœltiples gÂŽneros que invaden insectos y arÂ‡cnidos y los utilizan como hospederos para obtener nutrientes y propagar sus esporas. Se clasifican en tres familias: Clavicipitaceae, Cordyicipitaceae y Op hiocordycipitaceae. RealizÂŽ un estudio observacional en la regiÂ—n de Monteverde, Costa Rica, donde colectÂŽ y analicÂŽ artrÂ—podos que han sido parasitados con hongos en diferentes altitudes y zonas de vida. Mi objetivo era determinar si habÂ’a un gradiente al titudinal asociado con la presencia y abundancia de hongos parÂ‡sitos de artrÂ—podos, y cuÂ‡les rdenes eran los mÂ‡s frecuentes. La mayor abundancia de artrÂ—podos parasitados la encontrÂŽ en la altitud mÂ‡s baja, y la menor abundancia a la altura mÂ‡s alta. Sin embargo, no hay tendencia en abundancia a medida que aumenta la altitud. EncontrÂŽ la mayor abundancia de artrÂ—podos presentes en el Orden Hymenoptera en varias especies de avispas. Casi todos los especÂ’menes presentan alta variaciÂ—n en morfologÂ’as fÂœngicas que van desde hongos que
Abundance and Diversity of Endoparasitic Fungi Sandler 2 semejan moho hasta cuerpos fructÂ’feros. Este estudio proporciona tambiÂŽn descripciones detalladas de cada muestra de artrÂ—podos parasitados, incluyendo el microhÂ‡bitat especÂ’fico en el que se encontrÂ— y el mÂŽtodo de fijaciÂ—n al su strato. Estas descripciones detalladas revelan la alta variaciÂ—n en la cual estos hongos parasÂ’ticos de artrÂ—podos pueden atacar a varios artrÂ—podos en una variedad de ecosistemas. There are more than 700 species of entomopathogenic fungi that fall withi n the order s Hypocreales and Entomophthorales (Roy et al. 2005). Recent phylogenetic studies conducted in 2007 have revealed that multiple genera of arthropod pa rasitic fungi should be divided in clades of the following three families : Clavicipitaceae, Cordycipitaceae, and Ophiocordycipitacea e (Sung et al. 2007 ). Pr ior to this study, all endoparasitic fungi including the commonly recognized genus Cordyceps, were categorized in the family Clavicepitaceae ( ibid. ) That being said, minimal amounts of resea rch are available to correctly identify these fungi to species level. However, a universal characteristic of parasitic fungi is the behavioral manipulations they inflict the arthropod host. F ungal endo parasite s target a broad range of arthropod hosts including: Hymenoptera, Lepidopt era, Hemiptera, Coleoptera and Ara neae (Weber and Webster, 1970). Fungal spores are spread by the wind onto the forest floor where they can survive in soil and produce infective spores that eventually germinate on their next host (Roy et al. 2005). Fungal spores can enter the body of the host organism thro ugh the respiratory tract, anus, mouth or by p enetrating the cuticle (Stamets 2005). On ce the spores germinate inside the exoskeleton of the host they become incredibly exploitive and feed off of nutritional living tissue ( ibid. ). The fungus initiate s neurological control by compelling the host to migrate to preferred conditions such as lea ves or tree branches T he victim attaches itself to the substrate and then dies ( ibid. ). est explained by studies that have analyzed that pathogens can alter the host s nervous system (Roy et al. 2005). This altered nervous system tendency justifies the behavioral mechanism of mi grating to unusual environments which 2005 ). The reasoning for this is that seeking conditions with higher temperatures can reduce pathogen induced mortality in arthropods ( Roy et al. 2005). This fungal behavior ensures that spores can spread wider and more effectively off the ground than they do on the forest floor (Hughes et al. 2011). Victims use a va riety of methods to secure themselves on substrates by biting with their mandibles, wrapping t heir legs around the substrate, pressing wings or by growth from the body of the arthropod The next stage of para sitism is growth of the fungus which can take the form of a mushroom frui ting body, multiple fruiting bodies, or a mold looking substance which eventually emerge s (Stamets 2005). T ropical forest ecosystems provide ideal habitats for fungal spores and parasitic fungi due to high levels of humidity, dense vegetation growth, as well as a diversity of arthropod hosts (Mata 1999) Previously conducted studies have revealed that the biotic and abiotic environment is correlate d to fungal activity (Roy et al. 2005). For example, humidity above 95% is required for the fungus to germinate, infect and sporulat e (Roy et al. 2005) That being said, m y central research goals aimed to analyze if there is an altitudinal gradient associat ed with the presence and abundance of arthropod parasitic fungi and which arthropod Order is most infected i n the Monteverde region of Costa Rica. I predicted there to be the
Abundance and Diversity of Endoparasitic Fungi Sandler 3 highest abundance of arthropods at the highest altitude. The overall purpose of t his study is to provide insight about life zones in Costa Rica that arthropod parasitic fungus is present in and discuss the morphological and behavioral manifestations of these fungi on their hosts. MATERIALS AND METHODS Field Methods The observa tional portion of my study occur red beginning November 16 until November 26 at four different life zones and altitudes. I gather ed data from tropical premontane rain forest in the lowland s of San Gerardo which is designated as site resting at 900masl (meters above sea level) I sampled tropical premontane wet forest along the Rachel and Dwight Crande ll Memorial Reserve Trails behind the Monteverde Institute which corresponds to mid el at 1 3 00masl The id site for data collection is 1 575masl in tropical lower montane wet forest at the EstaciÂ—n BiolÂ—gica Monteverde The last sample d tropical lower montane rain forest at 170 0masl near the T.V T owers. I searched at each site for nine hours, except at the TV towers where I spent four hours searching total At each site I searched for samples on any substrate such as the underside of leaves, t he forest floor as well as stems and trunks of trees When I found an arthropod with parasitic fungus, I documented : date altitude site height from the forest floor, substrate on w hich it was found, arthropod host the appearance of the fungus and additional observations. I took photographs in the field of the samples and then carefully collected them in small plastic containers Laboratory Methods Under the microscope, I captured detailed photographs in order to closely identify how the organisms were attached to the subs trate and where the fruiting bodies or fungus is emerging from the specimen I recorded morphological details of the fungus of every sample. Viewing the organisms under intense magnification allowed for accurate identification of the arthropod species. RESULTS I indentified 22 total individuals infected with parasitic fungi in the Monteverde Region. I found a total of nine hymneopterans, four hemipterans, four Araneae, three lepidopterans, one C oleoptera and one Opiliones (Fig 1) In my lowest altitude, there were a total of 12 individuals; low mid elevation had three individuals, mid elevation had seven individuals and the highest elevation had zero individuals with endoparasitic fungi (Fig 2). The highest abundance of arthropods was in the order hymeno ptera all of which were wasps, and were found most abundantly in San Gerardo and the EstaciÂ—n BiolÂ—gica T he highest abundance of Hemiptera and Araneae were found in San Gerardo (Fig 1). There is no clear trend in altitudinal abundance therefore my data does not support my initial pr ediction of the most abundance found at the highest altitude.
Abundance and Diversity of Endoparasitic Fungi Sandler 4 In my results I described each individual sample that I found in detail in order to highlight the incredible variation in host species, methods of attachment, and fungal appearance. I have organized the descriptions into categories by altitude and then subcategories that are arranged by Order of arthropod. Each description includes the order or species of arthropod, a measurement of the length of the body of the insect for perspective # $ % & ( ) + #" Individuals Orders TV Towers 1,700masl Station 1,575masl Institute 1,300masl San Gerardo 900masl $ & ( #" #$ #& # $ % & Individuals Altitude (masl) 900 1300 1575 1700 Figure 1. Individual arthropod abundance by Order at four altitudes Figure 2. Abundance of individuals found at each corresponding altitude.
Abundance and Diversity of Endoparasitic Fungi Sandler 5 the substrate that it was found on, how high off of the ground it was, how the specimen was attached to the substrate, and detailed description s of the fungus. There are samples that I believe are parasitized by the same species of fungus so I have comb ined them in to one comprehensive analysis Refer to Figure 3 for detailed photographs of each sample. Low Elevation: 900masl Hemiptera Hemiptera A is a n adult mimic of a tarantula hawk wasp and has a 3.2cm long body (Fig 3 A), found one meter above the ground on the top of a leaf from a c hayote plant. The specimen was not attached to t he leaf but displayed signs of endoparasitic fungus. The fungus on the hawk wasp appears as a mold looking substance with no fruiting bodies. There is w hite, fuzzy textured growth emerging from the ventral wing junctions, the bottom of the antennae, junctions of all of the legs (where the leg connects to the body as well as the ng from the abdomen. Hemiptera B is an adult leaf hopper, Cicadellidae with a 0.8cm long body (Fig 3 B), found 70cm above the forest floor on the underside of a leaf in a tree It is biting the central vein of the leaf with its mouthparts and is not attached to the substrate with any other part of its body. The fungus is present on the dorsal side of the leaf hopper on the wings, abdomen, antennae, head, and thorax. The fruiting bodies resemble hairs; they are translucent and white, and so ft with erratic stipes or stems ( neither completely straight nor necessarily curved). The fruiting bodies range from 0.1cm 0.5cm long and have no visible pilei (cap) Hemiptera C, is a Reduviidae and has a 1.3cm long body (Fig 3 C) found 75cm off the gro und on the underside of a leaf on a tree It is attached to the leaf by using the tips of its feet stabbing the leaf tissue It is s traddling the central vein of the leaf with three feet on either side with its body is completely raised above the leaf. The fungus is present on the ventral and dorsa l side of the head, thorax, abdomen, knee joints and tips of feet. On the abdomen, there is dense, fuzzy white fungus covering it entirely. From the thorax to the head there are protruding fruiting bodies that vary from 0.1cm 0.3cm in l ength. These fruiting bodies are white and columnar, mostly str aight with some curvature on longer bodies and there are no p ilei. The joints of the knees on all six legs have between one and three of these columnar fruiting bodies emerging Hemiptera D is 0.5cm long (Fig 3 D) and was found on the underside o f a leaf 50cm above the ground i n a shrub The specimen is attached on the central vein of the leaf but due to the high density of the fungus it is difficult to see exactly how it is attached. The fungus emerges 0.2cm out of the body and covers the entire visi ble surface of the specimen. I t is a fuzzy, dense, off white colo red fungus. Under a microscope, the filaments that make u p the fungus contain micro stipes with circular pilei. Araneae
Abundance and Diversity of Endoparasitic Fungi Sandler 6 Araneae E is a wolf s pider, Lycosidae and has a 0.5cm long body (Fig. 3 E) found 60cm above the fore st floor on the underside of a fern nestled above the CaÂ–o Negro river Ventral fungal growth is attaching t he spider to the leaf. The fungus is a fuzzy white mold looking substance coating the entire ty of its body and halfway down all eight of its legs. There are no protruding fruiting bodies or pilei visible with a microscope. The fungus is Araneae F, Cetnidae, a wandering spider, approximately 1.7cm long (Fig 3 F) and was found 1.3m above the forest floor on the underside of a leaf from a vine that was growing from a tree When dissected, this spider was hollow on the inside which indicates that it is a very old specime n This spider is attached by fungal growth on the ventral side of its cephalothorax. The fungus is a fuzzy mold looking substance and has a white and grey pigmen t There are no protruding fruiting bodies or visible pilei. The fungus is coating th e legs. Araneae G, C tenidae is 0.9cm l ong (Fig 3 G), found 40cm above the CaÂ–o Negro River on the underside of a leaf F ungal growth on dorsal side of the cephalothorax is attaching this specimen to the leaf. The f ungus covers the entire dorsal side of the spider as well as m ore than half way down the eight legs. On the head and cephelotho rax of the spider, the fungus has a mold substance fungus with yellow white pigment. The fungus that is spread onto the legs has a dominantly white pigment. There are no visible fruiting bodie s or pilei. Hymenoptera Hymenopterans H and I are both species Parachartergus fraternus and are 1.5cm long (Fig 3 H & I) I found them in the same tree and the fungal traits are nearly identical, which leads me to believe that they are likely parasitized by the same species of fungus. One individual is attached to a stem by biting with its mandibles or is attached by a fungus that is growing from its mouth connecting it to the stem (Fig 3 H) Second individual (Fig. 3 I ) is also attached to th e stem and wrapping it s legs in a death grip around the stem T here is fungal growth emerging from the mouth that is also securing the wasp to the stem Fruiting bodies protrude from ante nnae, wing junctions wings the mselves, dorsal tergites (alternate colored stripes) on the abdomen, dorsal thorax and head. The fruiting bodies are thin and vary i n structure: stick straight to slightly curved and vary in length from 0.1cm to 2.0cm. The fruiting bodies have microscopic (>0.1cm wide) ovoid shape d pilei. Hymenoptera J, Agelaia areata is approximately 1cm long (Fig 3 J 1, J2 ) and was found in a tree 1.1m above the forest floor on the underside of a leaf. The wasp is attached to the side of the leaf and is attached by biting with its mandibles and wrapping each front leg and each antennae around the side of the leaf. This wasp was completely upside down with the fruiting bo dy parallel to the forest floor There is a large 4.5cm protruding fruiting body emerging from the posterior ventral side of the abdomen The fruiting body is thin with slight curvature and a cylindrical pileus that is less than 0.1cm wide visible under a microscope. This fruiting body ha s seven additional nodules protruding from it that are approximately 1cm long with curvature and 0.1cm wide pilei. In addition, there are two parallel fruiting bodies emerging fr om the joints of the wings. These fruiting bodies are both 1cm long with
Abundance and Diversity of Endoparasitic Fungi Sandler 7 sligh t curvature and microscopic pilei. These same structure fruiting bodies are also emerging from all four legs. Lepidoptera Lepidoptera K is an adult moth that is 1cm long (Fig 3 K ) ; f ound 70cm above a grass field on the underside of a leaf The moth is a ttached to the leaf by fungal growth on the There is fungal growth emerging from the veins of the wings on the dorsal side and the head. On the veins there is a strip of whi te, fuzzy, mold looking growth The wing veins also have yellow green 0.1cm long fruiting pro and a subtle poi nt toward the top of the fungus sparsely dispersed down the veins of the wings. Lepidoptera L is an adult moth that is 1.2cm long (Fig 3 L) and is attached to the underside of a fallen Cecropia leaf that had landed in a shrub 40cm off the ground. This specimen is coated in a bright yellow fung us that cove rs nearly the entire dorsal side of the body including : head, abdomen, win gs, and legs. The moth is attached to the leaf by fungus tha t is growing from the wings which are both stretched onto the surface of the leaf and is attached by fungal growth under t he ventral side. The majority of the fungus coating the dorsal side of the body is relatively un iform in size and length and is about 0.2cm lon g Growing from the dorsal 0.5cm long fruiting bodies that have a slight curvature and club shape with no identifiable pileus structures. Low Mid Elevation 1,300masl: Lepidoptera Lepidoptera M is caterpillar pupa Mimallonidae that 3cm long (Fig 3 M). It was found inside a leaf cocoon growing from a branch in a tree 1.2m above the forest floor The outer leaf of the cocoon has two mushroom bodies that are bright yellow short and stubby with no pileus The cocoon was dissected in the lab. The pupa has m ultiple 1 1.5cm long, bright yellow club shaped fruiting bodies growing on the head. There are darker yellow spots interspersed on the stipe which is where the spores are contained. The fungus gets progressively more swollen towards the top but lacks a wel l defined pileus. Hymenoptera Hymenoptera N is a wasp that is 1.5cm long (Fig 3 N1, N2 ); found 55cm above the forest floor on the side of a leaf in a shrub It is biting on to the leaf tissue with its mandibles and has one leg wrapped around the edge of the leaf. This wasp has lost its wings and ovipositor. Its abdomen and thorax are raised up above the leaf, so the mouthparts are the only location the wasp is actually attached to the leaf Th e fungus is composed of long light brown fruiting bodies with varying lengths that are emerging from: the antennae, the head, the legs the yellow terg ites on There are three 1cm fruiting bodies with curved stipes that have fuzzy ovoid shaped pilei emerging from the thorax. thorax there are two parallel fruiting bodies that are 0.5cm long and are both relatively
Abundance and Diversity of Endoparasitic Fungi Sandler 8 straight with pilei. Some of the smaller fruiting bodies have developed caps and some have not Hymenoptera O, is the species Agelaia yepocapa is approximately 1.5cm (Fig 3 O); found 1.3m above the forest floor on the side of the leaf. It is biting onto the leaf with its mandibles and has three legs and both antennae gripping the leaf on either side The fruiting bodies of the mus hrooms are long and thin with curvature and microscopic ellipsoidal pilei It is difficult to measure the fruiting bodies accurately of this specimen because there is so much curvature of the fungus There are multiple long fruiting bodies coming out of the generated underneath the mandibles of the wasp where it is biting the leaf The antennae have an abundance of miniscule frui ting bodies emerging from them. T he bl ack turguites on the abdomen of the wasp have fruiting bodies while none of the yellow turguites abdomen have fruiting bodies emerging from them. T here is a fruiting body growing from the tip of the abdomen. It appears that the mycelium has spr continued spreading throughout the surface of the leaf. Mid Elevation 1,547masl: Hymenoptera Hymenoptera P is an a dult wasp in the family Vespidae Polistes instabilis and is 2.2cm long (Fig 3 P). It is attached to the stem of a leaf 75cm from forest floor The wasp is attached to the stem with all sets of legs wrapped around in a death grip The h ead is tucked down onto stem but the mandibles are not attached. There are multiple varying length fruiting bodies coming out of the abdomen, head, wing joints and legs. Some of the longer fruiting bodies have micro stipes growing from the primary stipe. The f ruiting bodies have curvature and are not uniform in color. The fungus has microscopic pilei that are slightly fuzzy. Hymenoptera Q is an adult wasp roughly 1.5cm long (Fig 3 Q ) and is attached to the underside of a leaf 1.3m off the forest floor It is wrapping two of its legs around the side of leaf for attachment. There is an emergence of fungus growi ng underneath is mouth parts that is connectin g it onto the surface of the leaf There is one visible 1.2cm long fruiting body growing from the dorsal side on the base of the head that has an orange pigment The pileus is an ovoid shape that has fertile pimp les where the spores are stored There are 0.3cm long fruiting bod ies growing out of the tip of the second and third legs that do not have caps. T hey are short columnar f ruiting bodies with an orange tint growing perpendicular from the leaf Hymenoptera R is an adult wasp 1.3cm long (F ig 3 R ) is attached to the underside of a leaf by the fungus that is growing underneath its mandibles and at the bottom of its abdomen and thorax The fungus has an orange mold looking substrate growing undernea posterior abdomen and anterior thorax that is attaching the wasp to the leaf. There are 0.3cm long fruiting bodies with no pilei growing perpendicularly out of the tip of the second and third legs There is one 1cm long fruiting body with a p ileus c oming out of the dorsal side on the base of the head The pileus has and ovoid shape with fertile pimples that act as spore pockets.
Abundance and Diversity of Endoparasitic Fungi Sandler 9 Hymenoptera S is a wasp in the family Vespidae and is 2cm long (Fig 3 S ). The wasp was found on t he underside of a fern 50cm above the forest floor. It is attached to the leaf by a fungal growth spewing from its mouth and abdomen as well as its right leg that is wrapping around t he leaf. There are four 0.5cm long fruiting bodie s with similar structures that all have an orange pigment, curved stipes and ovoid shaped pilei that contain fertile pimples. Three of the fruiting bodies are emerging from the head and neck of the wasp and the other body is on the posterior dorsal side of the thorax. There are thin 0.6cm long columnar fruiting bodies emerging from the hind legs and one emerging from the junction of the abdomen and thorax. These bodies all have an orange pink pigment and lack evident pilei Araneae Araneae T is likely in the family Theridiidae that is 0.2cm long (Fig 3 T ) ; f ound on the underside of a leaf 1.5m above the forest floor Fungal growth on the ventral leaf of its body is attaching the organism to the leaf It is not clear if the spider is biting onto the leaf becau se it is covered in fungus There are three fruiting bodies emerging from the top of cephelothorax Each fruiti ng body is roughly 0.3cm long with club shaped stipes that have no clear pillei. Each stipe has abundant m icro mushro om structures that are white and fuzzy. Opiliones Opiliones U is a H arvestman t ha t is 0.3cm long (Fig 3 U1, U2 ); found on the underside of a large leaf 1.2m off forest floor Fungal growth is attaching the ventral side of the body to the leaf; their mandibles are too small to grasp onto the substrate. T he re is a white mold looking fungus There is one 1.3cm long fruiting body emerging from the center of its body. The struct ure is columnar with slight curvature and lacks a pileus The stipe is a light yellow color and has small white cott on ball looking structures covering the entire stipe The joints of the legs appear to have the white mold looking fungal growth as well. Coleoptera Coleopter a V is an adult weevil in the family Curculionidae approximately 1cm long (Fig 3 V1, V2 ), attached to a mossy branch 1.75m above the forest floor The legs are wrapped around branch in a death grip There is one visible fruiting body coming out of the otum (plate like structure that covers the thorax) The fruiting body is 1.2cm long and is characteristic for having a notable color gra dient. One millimeter of the e is black and smooth and 0.3cm of the stipe is a dark pink/pea ch color. The pileus of the mushroom is a light peach shade with an ellipsoidal shape and contains fertile pimples wh ere the spores are contained
Abundance and Diversity of Endoparasitic Fungi Sandler 10 Figure 3 Photos of arthropod parasitic fungi in four different
Abundance and Diversity of Endoparasitic Fungi Sandler 11 Figure 3 Photos of arthropod parasitic fungi in four different altitudes. Photos captured by FÂŽlix Salazar. captured by Madeline Sandler.
Abundance and Diversity of Endoparasitic Fungi Sandler 12 DISCUSSIO N My study has revealed that there is no evident trend in abundance of parasit i zed arthropods in tropical forest ecosystems as altitude increases. Nonetheless there is amazing variation in host organisms and fungal morphologies that I discovered in four different life zones in the Monteverde region. All of my samples were situated on sub strates above the forest floor. This is notable because I did not find any other parasitic fungi lower than 40cm above the forest floor. Mycelium Running: How Mushrooms Can Help Save the World when he explains that chemical compounds in the fungus compel the insect to ascend to substrates above the forest floor because this ensures a wider distribution of spores than otherwise possible near the ground (Stamets 2005). The fungus manipulates the h ost to enhance its own fitness by guaranteeing effective spore dispersion and protection from weather and dangers present on the forest floor such as predation. There is variation between nearly ever y specimen that reveals how fungus targets arthropods d ifferently and inflicts specific behavioral tendencies. For example, every host that I discovered had a unique method to attach itself to the leaf. Among the Hymenoptera, all wasps were discovered to use their legs antennae or mandibles as ways to secure onto the substrate. In Araneae and Opiliones species, all samples were attac h ed to the substrate by fungal growth on the dorsal sides of their bodies that myceliated into the leaf tissue. Likewise, both lepidopteron moth individuals displayed a similar met hod of attachment by using their legs to grip onto the surface of leaf and by also firmly pressing their wings onto the leaf tissue. Unique individuals Figure 3 Photos of arthropod parasitic fungi in four different altitudes Photos captured by FÂŽlix by Madeline Sandler
Abundance and Diversity of Endoparasitic Fungi Sandler 13 include the Hawk Wasp mimic (Fig 3 A) that was found simply lying dead on the leaf with no physical atta chment to the substrate. Although there is evident fungal growth from the body of this insect, it is an unusual behavior that the individual was not attached to the substrate in any way. Additionally, the pupa of Mim a llonidae had been parasit i zed in its co coon and subsequently died in a tree 1.2 meters above the forest floor. Notably, all but two of my zombified samples were found solitary in their respective habitats. The two wasps I found that are the same species likely have the same fungal parasite and were both in low elevation roughly 30cm apart in the same tree. I n 1987, Nnakumusana described the behavior of social insects when recognizing fungal pathogens in mem bers of the colony. He discussed that worker ants physically remove infected individ uals away from the colony where they could potentially infect other s. This justifies why many samples were discovered on substrates isolated from other arthropods. Although these individuals are the primary mechanism for the survival of the parasite, their solitary location above the forest floor protects them and provides optimal spore dispersal conditions. In addition, there are many interesting variations in fungal morphotypes that take unique forms on every arthropod host. For example, every individua l wasp I found has protruding fruiting bodies coming from multiple locations on the body. These fungi vary in species as well as target host species. Fungi vary from thin structures that are densely abundant to few singular fruiting bodies that appear like Curculionidae weevil (Fig 3 V1, V2 ) has an incredibly unique fruiting body compared to other samples that is characteristic of its color gradient with blac k stipe and vibrant pink colored pileus. That bei ng said, the fungus can present a variety of vibrant colors such as the yellow fruiting bodies in both the Mimallonidae pupa (Fig. 3 M) and Lepiodoptera moth (Fig 3 L) or can present itself in more neutral brown or off white tones which a re evident in the vast majority of individuals (Fig 3 H, I, O) Interesting observations regarding the Lepidoptera (Fig 3 L) was that it was found on the underside of a dead Cecropia leaf. This leaf had fallen from the host tree and situated itself in a shrub 40cm above the ground. Cecropia trees can grow up to 25m tall and certain species can even reach heights of 40m (Zu chowski 2007). That being said, an interesting behavioral consideration to note is whether or not this specimen migrated to the Cecropia leaf because of the fungal parasite when the leaf was still attached to the Cecropia tree or after the leaf had already fallen. An additional observation in regards to Polistes instabilis (Fig 3 P) i s that t his is a migratory wasp species that flies up to Monteverde for the dry season. It is rather thought provoking to consider whether the wasp contracted the parasitic fungus in the lowlands and migrated upwards with the parasite, or rather if it cont racted the fungus during its time in Monteverde. Furthermore, in my research I did not find incidence of the Order Opiliones observed with endoparasitic fungi. I found one Opiliones in mid elevation site (Fig 3 U 1, U2 ). At the high altitude site of 1,700masl near the TV Towers, I discovered a total of zero arthropods infected with a parasitic fungus. That being said, my data does not support my initial prediction of the most abundance at the highest altitude There is a large po ssibility that I was personally unable to find arthropods that have been parasitized by fungi, or that this ecosystem is unsuitable for fungal growth. For example, the humidity levels at this altitude could be
Abundance and Diversity of Endoparasitic Fungi Sandler 14 unsuita ble conditions for fungal spore surviva l due to high amounts of moisture in the form o f rain and cloud precipitation (Roy et al. 2005). In addition, I did not test this altitude for the same amount of time as my other sampled sites which is a factor that could contribute to my results. Inte resting areas of further study could be neurotoxin analysis of the chemicals released by the fungus that act to manipulate the behavior and brain function of arthropod hosts. I ponder whether or not the spores of parasitic fungi react in a way that cause h allucinogenic reactions inside the brain of the arthropod or what exactly that compels them to do certain behaviors. Namely, does the arthropod seek elevated environments due to loss of nutritional tissue inside their b ody due to the growing parasite, o r behavioral d in previous research by Elliot et al in 2002? In regards to sustainable agriculture, other areas of significant further study could be to address the possibility of using genera of fungi in the families: Clavicipitace a e Cordycipitaceae or Orphiocordycipitaceae as methods of biological pest control on agricultural systems that rely on use of pesticides. Overall, hunting for fungal parasites can be a challenge because they hide in truly unpredictable places and prese nt themselves in a variety of morphologies on a wide range of hosts I discovered a total of 22 individual arthropods infected with endoparasitic fungi in the Monteverde region. My results did not show a trend in altitudinal abundance but present incredibl e variation in host range at each sampled altitude. ACKNOWLEDGEMENTS I would first like to thank Emi lia Triana for her consistent enthusiasm, unwaverin g love of arthropods and for her willingness to guide me through this project while making me laugh consistently This project was a mutual learning experience for both of us and I am incredibly grateful to have worked with her. I would also like to thank SofÂ’a Arc e for her wonderful feedback and for her assuring positive and calming energy I would al so like to extend a much des erved message of gratitude to FÂŽ lix Salazar who is the mastermind behind a nearly all of the unbelievable photographs taken of my specimens. Huge thanks to Frank Joyce for being amazing and supportive fungi by helping me identif y some of my specimens and for inspiring me to continue my researc h with this topic beyond EAP Thank you to the Monteverde Institute for providing a wonderful lab, work space, and hot coffee. A final and very important thank you to my peers in this progra m for their assistance and gusto in helping me find some of my samples, I really appreciate each and every one of your presences in this journey we shared. LITERATURE CITED Barelli, L., Moonjely, S., Behie, S. W., & Bidochka, M. J. (2015). Fungi with multifunctional lifestyles: Endophytic insect pathogenic fungi Plant Mol Biol Plant Molecular Biology, 90(6), 657 664. doi:10.1007/s11103 015 0413 z Elliot SL, Blanford S, Thomas MB. 2002. Host pathogen interaction in a varying environment, behavioural fever and fitness. Proc. Biol. Sci. 269:1599 607
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