Wednesday, May 25, 2016
13:30 - 15:00

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13:30 - 13:45: / 311-312 FISH SCENT: EPISODE I – ORIGEN AND SPECIFICITY OF THE CUE THAT MAKE LARVAE (INSECTA) RUN SCARED FROM FISH

5/25/2016  |   13:30 - 13:45   |  311-312

FISH SCENT: EPISODE I – ORIGEN AND SPECIFICITY OF THE CUE THAT MAKE LARVAE (INSECTA) RUN SCARED FROM FISH Some prey respond to predator cues by altering their behaviour, but the response may depend on predator diet and identity. There are few data on how predator feeding status and diet affect the behaviour of aquatic insects and on the specificity of the response of these prey to different predators. We present the results of four bioassays conducted in microcosms to evaluate the relationship between predator fish diet, predator identity and the predator avoidance behaviour of mayfly prey of the genus to elucidate the origin and specificity of the antipredator response. Our bioassays identified mucus as the potential origin of the cue eliciting antipredator behaviour in , providing much needed insight into the specificity of fish-associated chemical cues that cause some prey to respond. Experimental approaches similar to the one used in this study may increase our understanding of the role of chemical cues in aquatic ecosystems.

Maruxa Álvarez ( Co-Presenter/Co-Author), Universidad de Vigo, maruxa@uvigo.es;


Andrea Landeira-Dabarca ( Co-Presenter/Co-Author), Universidad San Francisco de Quito, andrealandab@gmail.com;


Bobbi Peckarsky (Primary Presenter/Author), University of Wisconsin, bobbipeckarsky@gmail.com;


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13:45 - 14:00: / 311-312 FISH SCENT: EPISODE II – NATURE OF THE CUE THAT MAKE LARVAE (INSECTA) RUN SCARED FROM FISH

5/25/2016  |   13:45 - 14:00   |  311-312

FISH SCENT: EPISODE II – NATURE OF THE CUE THAT MAKE LARVAE (INSECTA) RUN SCARED FROM FISH Non-consumptive effects of predators on prey are now well-known from many systems, and there is growing evidence that they can have knock-on effects on individual fitness, life history, and population dynamics. It is well-established that mayflies use chemical cues to detect predatory fish. In fact, a recent study pointed up fish skin mucus as the origin of the cue that makes to change its behaviour. However, up to date there were no studies determining specific chemicals released by fish responsible for the antipredator behaviour in .To achieve that goal, we conducted a series of microcosm bioassays to test whether fish-mucus dwelling bacteria or specific chemical compounds of the mucus were responsible for the antipredator behaviour. Bioassays sequentially rule out different alternative explanations for the causal agent of responses to fish. Our results provide the first experimental evidence that mayflies recognize fish predators through microbially-mediated degradation products of polysaccharides in fish cutaneous mucus. Experimental approaches similar to the one used in this study may increase our understanding of the role of chemical cues in aquatic ecosystems.

Andrea Landeira-Dabarca (Primary Presenter/Author), Universidad San Francisco de Quito, andrealandab@gmail.com;


Maruxa Álvarez ( Co-Presenter/Co-Author), Universidad de Vigo, maruxa@uvigo.es;


Bobbi Peckarsky ( Co-Presenter/Co-Author), University of Wisconsin, bobbipeckarsky@gmail.com;


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14:00 - 14:15: / 311-312 WHAT IF STRUCTURE HAS MORE FUNCTION THAN WE REALIZE? WATER VELOCITY REGULATES HERBIVORY PRESSURE ON PODOSTEMUM CERATOPHYLLUM.

5/25/2016  |   14:00 - 14:15   |  311-312

WHAT IF STRUCTURE HAS MORE FUNCTION THAN WE REALIZE? WATER VELOCITY REGULATES HERBIVORY PRESSURE ON PODOSTEMUM CERATOPHYLLUM. Podostemum ceratophyllum has been described as the “Poster Child” of river impairment in Piedmont rivers due to the widespread decline of the plant, however surprisingly little is known about the plant’s ecology and what loss of the plant means to riverine ecosystems. We conducted a reciprocal transplant experiment in the Middle Oconee River, GA, to investigate herbivory on Podostemum and how herbivory may be regulated by water velocity. We then further investigated the effect of herbivory by excluding macroconsumers for 77 days using electrified exclosures. Our results indicated top-down regulation of plant biomass and water velocity-mediated herbivory pressure. Our estimates of yearly flux of Podostemum into the food web were similar to estimates for algal consumption, suggesting that this macrophyte can be an important basal resource. Developing a better understanding of how Podostemum is influenced by water velocity can inform river management strategies in regard to this important macrophyte.

James Wood (Primary Presenter/Author), University of Georgia, wood@uga.edu;


Jon Skaggs ( Co-Presenter/Co-Author), Univeristy of Georgia, jskaggs@uga.edu;


Mary Freeman ( Co-Presenter/Co-Author), US Geological Survey, mcfreeman@usgs.gov;


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14:15 - 14:30: / 311-312 MACROINVERTEBRATE COMMUNITY COMPOSITION, EMERGENCE RATE, AND FOOD WEB STRUCTURE OF NEOTROPICAL CLOUD-FOREST STREAMS IN MINDO, ECUADOR

5/25/2016  |   14:15 - 14:30   |  311-312

MACROINVERTEBRATE COMMUNITY COMPOSITION, EMERGENCE RATE, AND FOOD WEB STRUCTURE OF NEOTROPICAL CLOUD-FOREST STREAMS IN MINDO, ECUADOR We examined macroinvertebrate community composition in three low-order neotropical cloud-forest streams at Reserva Las Gralarias in Mindo, Ecuador. Basic food web structure (via stable isotope analysis) was also examined to explore potential food web structure between emerging stream insects and endemic glass frogs (Centrolenidae). Additionally, aquatic insect emergence was measured weekly for two months at a 2nd order stream in order to quantify emergence rate for these systems. Results show that as stream size increases from 1st to 3rd order, the macroinvertebrate communities shift from being collector-gatherer dominated (65.2 to 29.8%, respectively) to being scraper dominated (17.9 to 56.3%, respectively). Shredders are poorly represented in all streams (2.7, 3.3, and 2.0% for 1st, 2nd, and 3rd order stream, respectively) similar to reports from other tropical systems. Results from this study provide base-line physical, chemical, and biological data on these streams that can be effectively used to track environmental changes in land-use. As glass frogs depend on neotropical streams to breed, this study also emphasizes the importance of conserving these ecosystems.

Anna Harris (Primary Presenter/Author), Canadian Organization for Tropical Education & Rainforest Conservation, a.harrianna@gmail.com;


Blanca Rios-Touma ( Co-Presenter/Co-Author), 1_.Universidad de las Américas- Quito, Ecuador. Facultad de Ingenierías y Ciencias Agropecuarias. Ingeniería Ambiental. Unidad de Biotecnología y Medio Ambiente -BIOMA-Campus Queri, Calle José Queri y Av. Granados. Edificio #8, PB. Quito, Ecuador., briostouma@gmail.com;


Andrea C. Encalada ( Co-Presenter/Co-Author), Instituto BIOSFERA, Universidad San Francisco de Quito, Cumbayá, Ecuador Biológicas y Ambientales, Universidad San Francisco de Quito, Cumbaya, Ecuador, aencalada@usfq.edu.ec;


Eric Snyder ( Co-Presenter/Co-Author), Grand Valley State University, snydeeri@gvsu.edu;


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14:30 - 14:45: / 311-312 FOOD WEB STABILITY: ARE WET OR DRY WEBS DIFFERENT?

5/25/2016  |   14:30 - 14:45   |  311-312

FOOD WEB STABILITY: ARE WET OR DRY WEBS DIFFERENT? Understanding how network typology affects stability has increased considerably in the last decade as computer and social networks expand exponentially. The same analysis techniques can be used to assess one of the enduring questions in ecology - how are ecological networks (food webs) structured to ensure they survive the ravages of nature. We use these network metrics to assess whether the nature of a habitat affects food web stability. In a compilation of 94 binary webs we find that fragility is less in aquatic than terrestrial food webs as a result of greater interactions between individual species. This contrasts with the view from analysis of food web resilience where terrestrial habitats are generally held to have greater resilience. We believe food webs are structured in this way because aquatic habitats experience more regular environmental disturbances.

Russell Death (Primary Presenter/Author), Massey University, r.death@massey.ac.nz;


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14:45 - 15:00: / 311-312 SEASONAL VARIATION OF FISH AND MACROINVERTEBRATE BIOMASS SPECTRA IN SOUTHERN WEST VIRGINIA STREAMS

5/25/2016  |   14:45 - 15:00   |  311-312

SEASONAL VARIATION OF FISH AND MACROINVERTEBRATE BIOMASS SPECTRA IN SOUTHERN WEST VIRGINIA STREAMS Biomass size-spectra - the power-law scaling relationship between average individual size and community biomass - have often been studied in lake and marine ecosystems, but rarely in lotic systems. The objective of this study was to test for characteristic biomass spectra in small temperate streams. Seasonal fish and macroinvertebrate data, including population abundance and biomass estimates, were collected in three wadeable, southern West Virginia streams from March 2014 to October 2014. Fish abundances were estimated with 3-pass electrofishing (depletion) surveys. Macroinvertebrates were collected with a Hess sampler and returned to the lab for identification to the lowest practical level (usually genus), Published length-mass regressions were then used to estimate individual biomass. All size-spectra relationships (linear regression of log-log data) were highly significant (p<0.001). Size-spectra intercepts were variable and may reflect seasonal differences in fish and invertebrate densities. Size-spectra slopes were more constant, with a mean slope of approximately -0.73, suggesting a common scaling relationship between stream consumers at differing trophic levels.

Andrew Kirk (Primary Presenter/Author), Virginia Commonwealth University, andrew.kirk@deq.virginia.gov;


Daniel McGarvey ( Co-Presenter/Co-Author), Virginia Commonwealth University, djmcgarvey@vcu.edu;


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