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Aaron M Ellison - One of the best experts on this subject based on the ideXlab platform.
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regulation by the pitcher plant Sarracenia purpurea of the structure of its inquiline food web
bioRxiv, 2020Co-Authors: Aaron M Ellison, Nicholas J Gotelli, Leszek A Bledzki, Jessica L ButlerAbstract:Phytotelmata, the water-filled habitats in pitcher plants, bromeliad tanks, and tree-holes, host multitrophic food webs that are model experimental systems for studying food-web structure and dynamics. However, the plant usually is considered simply as an inert container, not as an interacting part of the food web. We used a response-surface and factorial field experiment to determine effects of nutrient enrichment (multiple levels of NH4NO3, PO4, and captured prey), top predator (removed or present), and the plant itself (with or without plastic tubes inserted into the pitchers to isolate the food web from the plant) on the macrobial food web within the modified leaves ("pitchers") of the carnivorous pitcher plant Sarracenia purpurea. Connection to the plant, addition of NH4NO3 and removal of the top predator significantly increased the food web9s saturation, defined as its trophic depth and number of interactions. No effects on food-web saturation resulted from addition of PO4 or supplemental prey. Plants such as S. purpurea that create phytotelmata are more than inert containers and their inhabitants are more than commensal inquilines. Rather, both the plant and the inquilines are partners in a complex network of interactions.
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proteomic characterization of the major arthropod associates of the carnivorous pitcher plant Sarracenia purpurea
Proteomics, 2011Co-Authors: Nicholas J Gotelli, Aaron M Ellison, Aidan M Smith, Bryan A BallifAbstract:The array of biomolecules generated by a functioning ecosystem represents both a potential resource for sustainable harvest and a potential indicator of ecosystem health and function. The cupped leaves of the carnivorous pitcher plant, Sarracenia purpurea, harbor a dynamic food web of aquatic invertebrates in a fully functional miniature ecosystem. The energetic base of this food web consists of insect prey, which is shredded by aquatic invertebrates and decomposed by microbes. Biomolecules and metabolites produced by this food web are actively exchanged with the photosynthesizing plant. In this report, we provide the first proteomic characterization of the sacrophagid fly (Fletcherimyia fletcheri), the pitcher plant mosquito (Wyeomyia smithii), and the pitcher-plant midge (Metriocnemus knabi). These three arthropods act as predators, filter feeders, and shredders at distinct trophic levels within the S. purpurea food web. More than 50 proteins from each species were identified, ten of which were predominantly or uniquely found in one species. Furthermore, 19 peptides unique to one of the three species were identified using an assembled database of 100 metazoan myosin heavy chain orthologs. These molecular signatures may be useful in species monitoring within heterogeneous ecosystem biomass and may also serve as indicators of ecosystem state.
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the pitcher plant Sarracenia purpurea can directly acquire organic nitrogen and short circuit the inorganic nitrogen cycle
PLOS ONE, 2009Co-Authors: Jim D Karagatzides, Jessica L Butler, Aaron M EllisonAbstract:Background: Despite the large stocks of organic nitrogen in soil, nitrogen availability limits plant growth in many terrestrial ecosystems because most plants take up only inorganic nitrogen, not organic nitrogen. Although some vascular plants can assimilate organic nitrogen directly, only recently has organic nitrogen been found to contribute significantly to the nutrient budget of any plant. Carnivorous plants grow in extremely nutrient-poor environments and carnivory has evolved in these plants as an alternative pathway for obtaining nutrients. We tested if the carnivorous pitcher plant Sarracenia purpurea could directly take up intact amino acids in the field and compared uptake of organic and inorganic forms of nitrogen across a gradient of nitrogen deposition. We hypothesized that the contribution of organic nitrogen to the nitrogen budget of the pitcher plant would decline with increasing nitrogen deposition. Methodology and Principal Findings: At sites in Canada (low nitrogen deposition) and the United States (high nitrogen deposition), individual pitchers were fed two amino acids, glycine and phenylalanine, and inorganic nitrogen (as ammonium nitrate), individually and in mixture. Plants took up intact amino acids. Acquisition of each form of nitrogen provided in isolation exceeded uptake of the same form in mixture. At the high deposition site, uptake of organic nitrogen was higher than uptake of inorganic nitrogen. At the low deposition site, uptake of all three forms of nitrogen was similar. Completeness of the associated detritus-based food web that inhabits pitcher-plant leaves and breaks down captured prey had no effect on nitrogen uptake. Conclusions and Significance: By taking up intact amino acids, Sarracenia purpurea can short-circuit the inorganic nitrogen cycle, thus minimizing potential bottlenecks in nitrogen availability that result from the plant’s reliance for nitrogen mineralization on a seasonally reconstructed food web operating on infrequent and irregular prey capture.
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a keystone predator controls bacterial diversity in the pitcher plant Sarracenia purpurea microecosystem
Environmental Microbiology, 2008Co-Authors: Celeste N Peterson, Aaron M Ellison, Benjamin E Wolfe, Roberto Kolter, Anne PringleAbstract:Summary The community of organisms inhabiting the waterfilled leaves of the carnivorous pitcher-plant Sarracenia purpurea includes arthropods, protozoa and bacteria, and serves as a model system for studies of food web dynamics. Despite the wealth of data collected by ecologists and zoologists on this food web, very little is known about the bacterial assemblage in this microecosystem. We used terminal restriction fragment length polymorphism (T-RFLP) analysis to quantify bacterial diversity within the pitchers as a function of pitcher size, pH of the pitcher fluid and the presence of the keystone predator in this food web, larvae of the pitcher-plant mosquito Wyeomyia smithii. Results were analysed at two spatial scales: within a single bog and across three isolated bogs. Pitchers were sterile before they opened and composition of the bacterial assemblage was more variable between different bogs than within bogs. Measures of bacterial richness and diversity were greater in the presence of W. smithii and increased with increasing pitcher size. Our results suggest that fundamental ecological concepts derived from macroscopic food webs can also be used to predict the bacterial assemblages in pitcher plants.
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A keystone predator controls bacterial diversity in the pitcher‐plant (Sarracenia purpurea) microecosystem
Environmental Microbiology, 2008Co-Authors: Celeste N Peterson, Aaron M Ellison, Benjamin E Wolfe, Roberto Kolter, Anne PringleAbstract:Summary The community of organisms inhabiting the waterfilled leaves of the carnivorous pitcher-plant Sarracenia purpurea includes arthropods, protozoa and bacteria, and serves as a model system for studies of food web dynamics. Despite the wealth of data collected by ecologists and zoologists on this food web, very little is known about the bacterial assemblage in this microecosystem. We used terminal restriction fragment length polymorphism (T-RFLP) analysis to quantify bacterial diversity within the pitchers as a function of pitcher size, pH of the pitcher fluid and the presence of the keystone predator in this food web, larvae of the pitcher-plant mosquito Wyeomyia smithii. Results were analysed at two spatial scales: within a single bog and across three isolated bogs. Pitchers were sterile before they opened and composition of the bacterial assemblage was more variable between different bogs than within bogs. Measures of bacterial richness and diversity were greater in the presence of W. smithii and increased with increasing pitcher size. Our results suggest that fundamental ecological concepts derived from macroscopic food webs can also be used to predict the bacterial assemblages in pitcher plants.
Thomas E Miller - One of the best experts on this subject based on the ideXlab platform.
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predator identity more than predator richness structures aquatic microbial assemblages in Sarracenia purpurea leaves
Ecology, 2018Co-Authors: Erin J Canter, Thomas E Miller, Catalina Cuellargempeler, Abigail I Pastore, Olivia U MasonAbstract:: The importance of predators in influencing community structure is a well-studied area of ecology. However, few studies test ecological hypotheses of predation in multi-predator microbial communities. The phytotelmic community found within the water-filled leaves of the pitcher plant, Sarracenia purpurea, exhibits a simple trophic structure that includes multiple protozoan predators and microbial prey. Using this system, we sought to determine whether different predators target distinct microorganisms, how interactions among protozoans affect resource (microorganism) use, and how predator diversity affects prey community diversity. In particular, we endeavored to determine if protozoa followed known ecological patterns such as keystone predation or generalist predation. For these experiments, replicate inquiline microbial communities were maintained for seven days with five protozoan species. Microbial community structure was determined by 16S rRNA gene amplicon sequencing (iTag) and analysis. Compared to the control (no protozoa), two ciliates followed patterns of keystone predation by increasing microbial evenness. In pairwise competition treatments with a generalist flagellate, prey communities resembled the microbial communities of the respective keystone predator in monoculture. The relative abundance of the most common bacterial Operational Taxonomic Unit (OTU) in our system decreased compared to the control in the presence of these ciliates. This OTU was 98% similar to a known chitin degrader and nitrate reducer, important functions for the microbial community and the plant host. Collectively, the data demonstrated that predator identity had a greater effect on prey diversity and composition than overall predator diversity.
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effects of a ciliate protozoa predator on microbial communities in pitcher plant Sarracenia purpurea leaves
PLOS ONE, 2014Co-Authors: Taylor K Paisie, Thomas E Miller, Olivia U MasonAbstract:The aquatic communities found within the water filled leaves of the pitcher plant, Sarracenia purpurea, have a simple trophic structure providing an ideal system to study microscale interactions between protozoan predators and their bacterial prey. In this study, replicate communities were maintained with and without the presence of the bactivorous protozoan, Colpoda steinii, to determine the effects of grazing on microbial communities. Changes in microbial (Archaea and Bacteria) community structure were assessed using iTag sequencing of 16S rRNA genes. The microbial communities were similar with and without the protozoan predator, with>1000 species. Of these species, Archaea were negligible, with Bacteria comprising 99.99% of the microbial community. The Proteobacteria and Bacteroidetes were the most dominant phyla. The addition of a protozoan predator did not have a significant effect on microbial evenness nor richness. However, the presence of the protozoan did cause a significant shift in the relative abundances of a number of bacterial species. This suggested that bactivorous protozoan may target specific bacterial species and/or that certain bacterial species have innate mechanisms by which they evade predators. These findings help to elucidate the effect that trophic structure perturbations have on predator prey interactions in microbial systems.
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nutrient limitation in detritus based microcosms in Sarracenia purpurea
Hydrobiologia, 2006Co-Authors: Sarah M Gray, Thomas E Miller, Nicolas Mouquet, Tanguy DaufresneAbstract:Most prior work on the role of top-down and bottom-up effects in aquatic communities has ignored the significant detrital component that occurs in natural systems. We investigated the effects of specific nutrients (carbon, phosphorus, and nitrogen), as well as a top predator (the mosquito Wyeomyia smithii), on the structure of the detritivore community found in the water-filled leaves of the pitcher plant Sarracenia purpurea. The concentrations of three nutrients and the presence of the predators were manipulated in a factorial design, while the response of the remaining community was quantified. Bacterial growth was found to be strongly carbon-limited and somewhat less limited by phosphorus and there was an interaction between the effects of the two nutrients. Neither carbon or phosphorus addition affected protozoan or rotifer abundance, and nitrogen had only a minor effect. The presence of the predator, however, significantly reduced the abundance of the four numerically dominant bacteriovores. There were no interactions between top-down and bottom-up effects; the strong direct reciprocal effects between adjacent trophic levels seem to be greatly attenuated as they are propagated farther up or down the food chain.
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morphological variation in Sarracenia purpurea Sarraceniaceae geographic environmental and taxonomic correlates
American Journal of Botany, 2004Co-Authors: Aaron M Ellison, Thomas E Miller, Hannah L Buckley, Nicholas J GotelliAbstract:Geographic variation in morphology reflects phenotypic responses to environmental gradients and evolutionary history of populations and species and may indicate local or regional changes in environmental conditions. The pitcher plant (Sarracenia purpurea) illustrates these principles. At local scales, its morphology reflects nutrient availability. At points along its broad geographic range (from Florida to northern Canada) morphology has been used to distinguish subspecies and varieties, but there has been no detailed study of the continuum of morphological variation across this entire range. Patterns of morphological variation in S. purpurea were characterized as a function of climatic and environmental conditions at 39 sites spanning its range. Differences in pitcher size and shape were strongly correlated with temperature, annual precipitation, and availability of ammonium and calcium in peat pore water. Pitcher shape (lip width, mouth diameter, and pitcher width) in Florida panhandle populations differed significantly from pitcher shape of all other populations, even after accounting for environmental correlations. In contrast, the northern and southern subspecies of S. purpurea (the latter exclusive of the Florida panhandle populations) cannot be distinguished based on these morphological measurements alone. These results support a recent proposal that identifies the Florida populations as a distinct species, Sarracenia rosea.
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dispersal rates affect species composition in metacommunities of Sarracenia purpurea inquilines
The American Naturalist, 2003Co-Authors: J. M. Kneitel, Thomas E MillerAbstract:Abstract: Dispersal among local communities can have a variety of effects on species composition and diversity at local and regional scales. Local conditions (e.g., resource and predator densities) can have independent effects, as well as interact with dispersal, to alter these patterns. Based on metacommunity models, we predicted that local diversity would show a unimodal relationship with dispersal frequency. We manipulated dispersal frequencies, resource levels, and the presence of predators (mosquito larvae) among communities found in the water‐filled leaves of the pitcher plant Sarracenia purpurea. Diversity and abundance of species of the middle trophic level, protozoa and rotifers, were measured. Increased dispersal frequencies significantly increased regional species richness and protozoan abundance while decreasing the variance among local communities. Dispersal frequency interacted with predation at the local community scale to produce patterns of diversity consistent with the model. When predat...
D E Schnell - One of the best experts on this subject based on the ideXlab platform.
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Sarracenia purpurea l ssp venosa raf wherry variations in the carolinas coastal plain
2016Co-Authors: D E SchnellAbstract:Anthocyanin pigment variants of Sarracenia purpurea L. ssp. venosa (Raf.) Wherry were studied in the Carolinas coastal plain. The variations noted are: 1) red veined green pitcher leaves vs. all red/maroon leaves; 2) varying intensity of anthocyanin pigments in sepals; and 3) varying intensity of red color of petals. Data collected in this study and previous related studies indicate that these variations are genetic. The variation in petal color intensity is not directly related to sepal and pitcher color patterns, although the latter two are to each other. In shaded situations, nearly all pitcher leaves are veined to some degree in this area, but in full sunlight some plants have the genetic capacity to produce all red/maroon leaves. It is concluded that these variations are not directly adaptive in present natural or transplant habitats. Possible adaptive significance in other situations is briefly discussed.
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(RAF.) WHERRY VAR. BURKII SCHNELL (SarraceniaCEAE)—A NEW VARIETY OF THE
1993Co-Authors: D E SchnellAbstract:A new variety of Sarracenia purpurea L. ssp. venosa (Raf.) Wherry is herein described as var. burkii. The variety is confined to the Gulf coastal plain and is characterized by pale pink to lavender petals and a white to pale green-white carpel, the umbraculate portion of the style being most apparent in this respect. Sarracenia purpurea L. ssp. venosa (Raf.) Wherry is a carniv orous pitcher plant found mainly in the coastal plain of the south eastern United States, with mountain extensions in the Carolinas. There is a gap in its range in southern Georgia, and populations occur again in the central Gulf coastal plain (Wherry, 1933; McDaniel, 1966; Schnell, 1976). The Gulf coastal populations are addressed in this paper. In 1933, Edgar Wherry (p. 4) commented on what he described as a "mutant" of Sarracenia purpurea with an almost white um braculate portion of the style and pale rose-pink petals, collected near Theodore, Alabama by Frank Morton Jones in 1910. Wherry found additional plants in 1932 (he did not specify exactly where, but implied southern Alabama) and sent them to Louis Burk of Philadelphia, an apparently well-regarded horticulturist of the day. The plants flowered true to the original description in Burk's greenhouse the following year. Wherry (1933) suggested the pos sibility of naming a horticultural variety in honor of Mr. Burk, but never did. Over a period of thirty-five years of botanizing the Sarracenia range, I have examined characters of North American pitcher plants in a series of papers (Schnell, 1978a, 1978b, 1979, 1981) in which S. purpurea ssp. venosa in the central Gulf coastal plain was mentioned. Gradually, I became impressed with the fact that nearly all specimens of the subspecies were similar to those de scribed by Wherry; rather than being a rare mutant, it is essentially the only form present. The floral characters described, their con
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Sarracenia purpurea l ssp venosa raf wherry var burkii schnell Sarraceniaceae a new variety of the gulf coastal plain
Rhodora, 1993Co-Authors: D E SchnellAbstract:A new variety of Sarracenia purpurea L. ssp. venosa (Raf.) Wherry is herein described as var. burkii. The variety is confined to the Gulf coastal plain and is characterized by pale pink to lavender petals and a white to pale green-white carpel, the umbraculate portion of the style being most apparent in this respect.
Anne Pringle - One of the best experts on this subject based on the ideXlab platform.
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superior dispersal ability leads to persistent ecological dominance by candida pseudoglaebosa in the Sarracenia purpurea fungal metacommunity
bioRxiv, 2018Co-Authors: Primrose J Boynton, Celeste N Peterson, Anne PringleAbstract:A large number of descriptive surveys document changes in microbial communities over time, but direct evidence for the ecological processes mediating succession or causing ecological dominance remains rare. Differential dispersal may be a key mechanism. We surveyed microbial diversity within a metacommunity of pitchers of the model carnivorous plant Sarracenia purpurea and discovered the yeast Candida pseudoglaebosa as ecologically dominant. Its frequency in the metacommunity increased over the growing season, and it was not replaced by other taxa. We next measured its competitive ability in a manipulative laboratory experiment and tracked its dispersal over time in nature. Despite its dominance, C. pseudoglaebosa is not a superior competitor. Instead, it is a superior disperser: it arrives in pitchers earlier, and disperses into more pitchers, than other taxa. Differential dispersal across the spatially structured metacommunity of individual pitchers emerges as a key driver of the continuous dominance of C. pseudoglaebosa during succession.
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a keystone predator controls bacterial diversity in the pitcher plant Sarracenia purpurea microecosystem
Environmental Microbiology, 2008Co-Authors: Celeste N Peterson, Aaron M Ellison, Benjamin E Wolfe, Roberto Kolter, Anne PringleAbstract:Summary The community of organisms inhabiting the waterfilled leaves of the carnivorous pitcher-plant Sarracenia purpurea includes arthropods, protozoa and bacteria, and serves as a model system for studies of food web dynamics. Despite the wealth of data collected by ecologists and zoologists on this food web, very little is known about the bacterial assemblage in this microecosystem. We used terminal restriction fragment length polymorphism (T-RFLP) analysis to quantify bacterial diversity within the pitchers as a function of pitcher size, pH of the pitcher fluid and the presence of the keystone predator in this food web, larvae of the pitcher-plant mosquito Wyeomyia smithii. Results were analysed at two spatial scales: within a single bog and across three isolated bogs. Pitchers were sterile before they opened and composition of the bacterial assemblage was more variable between different bogs than within bogs. Measures of bacterial richness and diversity were greater in the presence of W. smithii and increased with increasing pitcher size. Our results suggest that fundamental ecological concepts derived from macroscopic food webs can also be used to predict the bacterial assemblages in pitcher plants.
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A keystone predator controls bacterial diversity in the pitcher‐plant (Sarracenia purpurea) microecosystem
Environmental Microbiology, 2008Co-Authors: Celeste N Peterson, Aaron M Ellison, Benjamin E Wolfe, Roberto Kolter, Anne PringleAbstract:Summary The community of organisms inhabiting the waterfilled leaves of the carnivorous pitcher-plant Sarracenia purpurea includes arthropods, protozoa and bacteria, and serves as a model system for studies of food web dynamics. Despite the wealth of data collected by ecologists and zoologists on this food web, very little is known about the bacterial assemblage in this microecosystem. We used terminal restriction fragment length polymorphism (T-RFLP) analysis to quantify bacterial diversity within the pitchers as a function of pitcher size, pH of the pitcher fluid and the presence of the keystone predator in this food web, larvae of the pitcher-plant mosquito Wyeomyia smithii. Results were analysed at two spatial scales: within a single bog and across three isolated bogs. Pitchers were sterile before they opened and composition of the bacterial assemblage was more variable between different bogs than within bogs. Measures of bacterial richness and diversity were greater in the presence of W. smithii and increased with increasing pitcher size. Our results suggest that fundamental ecological concepts derived from macroscopic food webs can also be used to predict the bacterial assemblages in pitcher plants.
Annick Vilmenay - One of the best experts on this subject based on the ideXlab platform.
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Foreign mosquito survivorship in the pitcher plant Sarracenia purpurea – the role of the pitcher-plant midge Metriocnemus knabi
Hydrobiologia, 2000Co-Authors: Raymond L. Petersen, Andréa Faust, Jacqueline Nagawa, Chandi Thomas, Annick VilmenayAbstract:There are few reports of mosquito larvae other than those of the species-specific mosquito Wyeomyia smithii (Coq.) in leaves of Sarracenia purpurea L. We investigate why this might be so in two sets of experiments. In the first set, we compare the percent survivorship of W. smithii , Aedes aegypti (L.) and Anopheles stephensi Liston larvae when reared in intact pitcher plant leaves to in vitro rearings and we found that the survivorship of the Aedes and Anopheles larvae was close to zero when reared in the intact pitcher plant leaves compared to 37% and 64%, respectively, when reared in fish-food medium and 78% and 82%, respectively, when reared in pitcher-plant liquid. Wyeomyia smithii larvae had high percent survivorships under all three rearing conditions. In the second set of in vitro experiments, we compared the percent survivorship of W. smithii and Ae. aegypti larvae when reared in pitcher-plant liquid in the presence and absence of the larvae of the pitcher-plant midge, Metriocnemus knabi (Coq.) and found that the percent survivorship for W. smithii was high (90%) whether M. knabi larvae were present or absent. We also found that Ae. aegypti larval survivorship was 82% when M. knabi larvae were absent and less then 2% when present in the culture plates. Based on these findings, we suggest that M. knabi larvae prevent non- Wyeomyia mosquito taxa from exploiting the resources of S . purpurea leaves, thereby maintaining it as an exclusive mosquito niche for W . smithii . This is confirmed by visual observation of M. knabi attacking and devouring Aedes and Anopheles larvae, while at the same time leaving W. smithii larvae unharmed. Possibly the long setae of the W. smithii larva may prevent access to its body wall by the mandibles of the M. knabi larva. Application of these findings to other mosquito-plant associations is suggested.
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foreign mosquito survivorship in the pitcher plant Sarracenia purpurea the role of the pitcher plant midge metriocnemus knabi
Hydrobiologia, 2000Co-Authors: Raymond L. Petersen, Andréa Faust, Jacqueline Nagawa, Chandi Thomas, Annick VilmenayAbstract:There are few reports of mosquito larvae other than those of the species-specific mosquito Wyeomyia smithii (Coq.) in leaves of Sarracenia purpurea L. We investigate why this might be so in two sets of experiments. In the first set, we compare the percent survivorship of W. smithii, Aedes aegypti (L.) and Anopheles stephensi Liston larvae when reared in intact pitcher plant leaves to in vitro rearings and we found that the survivorship of the Aedes and Anopheles larvae was close to zero when reared in the intact pitcher plant leaves compared to 37% and 64%, respectively, when reared in fish-food medium and 78% and 82%, respectively, when reared in pitcher-plant liquid. Wyeomyia smithii larvae had high percent survivorships under all three rearing conditions. In the second set of in vitro experiments, we compared the percent survivorship of W. smithii and Ae. aegypti larvae when reared in pitcher-plant liquid in the presence and absence of the larvae of the pitcher-plant midge, Metriocnemus knabi (Coq.) and found that the percent survivorship for W. smithii was high (90%) whether M. knabi larvae were present or absent. We also found that Ae. aegypti larval survivorship was 82% when M. knabi larvae were absent and less then 2% when present in the culture plates. Based on these findings, we suggest that M. knabi larvae prevent non-Wyeomyia mosquito taxa from exploiting the resources of S. purpurea leaves, thereby maintaining it as an exclusive mosquito niche for W. smithii. This is confirmed by visual observation of M. knabi attacking and devouring Aedes and Anopheles larvae, while at the same time leaving W. smithii larvae unharmed. Possibly the long setae of the W. smithii larva may prevent access to its body wall by the mandibles of the M. knabi larva. Application of these findings to other mosquito-plant associations is suggested.