Stanford Advisors

All Publications

  • Pavement ant extract is a chemotaxis repellent for C. elegans. microPublication biology Lopez, J. S., Ali, S., Asher, M., Benjamin, C. A., Brennan, R. T., Burke, M. L., Civantos, J. M., DeJesus, E. A., Geller, A., Guo, M. Y., Haase Cox, S. K., Johannsen, J. M., Kang, J. S., Konsker, H. B., Liu, B. C., Oakes, K. G., Park, H. I., Perez, D. R., Sajjadian, A. M., Torio Salem, M., Sato, J., Zeng, A. I., Juarez, B. H., Gonzalez, M., Morales, G., Bradon, N., Fiocca, K., Pamplona Barbosa, M. M., O'Connell, L. A. 2024; 2024


    Ant behavior relies on a collection of natural products, from following trail pheromones during foraging to warding off potential predators. How nervous systems sense these compounds to initiate a behavioral response remains unclear. Here, we used Caenorhabditis elegans chemotaxis assays to investigate how ant compounds are detected by heterospecific nervous systems. We found that C. elegans avoid extracts of the pavement ant ( Tetramorium immigrans ) and either osm-9 or tax-4 ion channels are required for this response. These experiments were conducted in an undergraduate laboratory course, demonstrating that new insights into interspecies interactions can be generated through genuine research experiences in a classroom setting.

    View details for DOI 10.17912/micropub.biology.001146

    View details for PubMedID 38596360

    View details for PubMedCentralID PMC11002644

  • Argentine ant extract induces an osm-9 dependent chemotaxis response in C. elegans. microPublication biology Alfonso, S. A., Arango Sumano, D., Bhatt, D. A., Cullen, A. B., Hajian, C. M., Huang, W., Jaeger, E. L., Li, E., Maske, A. K., Offenberg, E. G., Ta, V., Whiting, W. W., Adebogun, G. T., Bachmann, A. E., Callan, A. A., Khan, U., Lewis, A. R., Pollock, A. C., Ramirez, D., Bradon, N., Fiocca, K., Cote, L. E., Sallee, M. D., McKinney, J., O'Connell, L. A. 2023; 2023


    Many ant species are equipped with chemical defenses, although how these compounds impact nervous system function is unclear. Here, we examined the utility of Caenorhabditis elegans chemotaxis assays for investigating how ant chemical defense compounds are detected by heterospecific nervous systems. We found that C. elegans respond to extracts from the invasive Argentine Ant ( Linepithema humile ) and the osm-9 ion channel is required for this response. Divergent strains varied in their response to L. humile extracts, suggesting genetic variation underlying chemotactic responses. These experiments were conducted by an undergraduate laboratory course, highlighting how C. elegans chemotaxis assays in a classroom setting can provide genuine research experiences and reveal new insights into interspecies interactions.

    View details for DOI 10.17912/micropub.biology.000745

    View details for PubMedID 37008729

  • Poison frog dietary preference depends on prey type and alkaloid load. PloS one Moskowitz, N. A., D'Agui, R., Alvarez-Buylla, A., Fiocca, K., O'Connell, L. A. 2022; 17 (12): e0276331


    The ability to acquire chemical defenses through the diet has evolved across several major taxa. Chemically defended organisms may need to balance chemical defense acquisition and nutritional quality of prey items. However, these dietary preferences and potential trade-offs are rarely considered in the framework of diet-derived defenses. Poison frogs (Family Dendrobatidae) acquire defensive alkaloids from their arthropod diet of ants and mites, although their dietary preferences have never been investigated. We conducted prey preference assays with the Dyeing Poison frog (Dendrobates tinctorius) to test the hypothesis that alkaloid load and prey traits influence frog dietary preferences. We tested size preferences (big versus small) within each of four prey groups (ants, beetles, flies, and fly larvae) and found that frogs preferred interacting with smaller prey items of the fly and beetle groups. Frog taxonomic prey preferences were also tested as we experimentally increased their chemical defense load by feeding frogs decahydroquinoline, an alkaloid compound similar to those naturally found in their diet. Contrary to our expectations, overall preferences did not change during alkaloid consumption, as frogs across groups preferred fly larvae over other prey. Finally, we assessed the protein and lipid content of prey items and found that small ants have the highest lipid content while large fly larvae have the highest protein content. Our results suggest that consideration of toxicity and prey nutritional value are important factors in understanding the evolution of acquired chemical defenses and niche partitioning.

    View details for DOI 10.1371/journal.pone.0276331

    View details for PubMedID 36454945

  • Body size correlations with female aggression and physiology suggest pre-adult effects on caste in an independent-founding eusocial paper wasp (Mischocyttarus pallidipectus, Hymenoptera Vespidae) ETHOLOGY ECOLOGY & EVOLUTION Fiocca, K., Congdon, R., O'Donnell, S. 2022
  • Social Network Analysis of Male Dominance in the Paper Wasp Mischocyttarus mastigophorus (Hymenoptera: Vespidae) JOURNAL OF INSECT BEHAVIOR O'Donnell, S., Fiocca, K., Congdon, R. 2021; 34 (3): 106-113
  • Reproductive physiology corresponds to adult nutrition and task performance in a Neotropical paper wasp: a test of dominance-nutrition hypothesis predictions BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY Fiocca, K., Capobianco, K., Fanwick, E., Moynahan, K., Congdon, R., Zelanko, P., Velinsky, D., O'Donnell, S. 2020; 74 (9)
  • Functionalized Single-Walled Carbon Nanotubes and Nanographene Oxide to Overcome Antibiotic Resistance in Tetracycline-Resistant Escherichia coli ACS APPLIED NANO MATERIALS Carver, J. A., Simpson, A. L., Rathi, R. P., Normil, N., Lee, A. G., Force, M. D., Fiocca, K. A., Maley, C. E., DiJoseph, K. M., Goldstein, A. L., Attari, A. A., O'Malley, H. L., Zaccaro, J. G., McCampbell, N. M., Wentz, C. A., Long, J. E., McQueen, L. M., Sirch, F. J., Johnson, B. K., Divis, M. E., Chorney, M. L., DiStefano, S. L., Yost, H. M., Greyson, B. L., Cid, E. A., Lee, K., Yhap, C. J., Dong, M., Thomas, D. L., Banks, B. E., Newman, R. B., Rodriguez, J., Segil, A. T., Siberski, J. A., Lobo, A. L., Ellison, M. D. 2020; 3 (4): 3910-3921
  • First person - Meghan Barrett and Katherine Fiocca BIOLOGY OPEN Barrett, M., Fiocca, K. 2019; 8 (12)

    View details for DOI 10.1242/bio.050187

    View details for Web of Science ID 000506171400021

  • Larval mannitol diets increase mortality, prolong development and decrease adult body sizes in fruit flies (Drosophila melanogaster) BIOLOGY OPEN Barrett, M., Fiocca, K., Waddell, E. A., McNair, C., O'Donnell, S., Marenda, D. R. 2019; 8 (12)


    The ability of polyols to disrupt holometabolous insect development has not been studied and identifying compounds in food that affect insect development can further our understanding of the pathways that connect growth rate, developmental timing and body size in insects. High-sugar diets prolong development and generate smaller adult body sizes in Drosophila melanogaster We tested for concentration-dependent effects on development when D. melanogaster larvae are fed mannitol, a polyalcohol sweetener. We also tested for amelioration of developmental effects if introduction to mannitol media is delayed past the third instar, as expected if there is a developmental sensitive-period for mannitol effects. Both male and female larvae had prolonged development and smaller adult body sizes when fed increasing concentrations of mannitol. Mannitol-induced increases in mortality were concentration dependent in 0 M to 0.8 M treatments with mortality effects beginning as early as 48 h post-hatching. Larval survival, pupariation and eclosion times were unaffected in 0.4 M mannitol treatments when larvae were first introduced to mannitol 72 h post-hatching (the beginning of the third instar); 72 h delay of 0.8 M mannitol introduction reduced the adverse mannitol effects. The developmental effects of a larval mannitol diet closely resemble those of high-sugar larval diets.This article has an associated First Person interview with the first author of the paper.

    View details for DOI 10.1242/bio.047084

    View details for Web of Science ID 000506171400012

    View details for PubMedID 31822472

    View details for PubMedCentralID PMC6955208

  • Brain structure differences between solitary and social wasp species are independent of body size allometry JOURNAL OF COMPARATIVE PHYSIOLOGY A-NEUROETHOLOGY SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY O'Donnell, S., Bulova, S., DeLeon, S., Barrett, M., Fiocca, K. 2019; 205 (6): 911-916


    Evolutionary transitions in social behavior are often associated with changes in species' brain architecture. A recent comparative analysis showed that the structure of brains of wasps in the family Vespidae differed between solitary and social species: the mushroom bodies, a major integrative brain region, were larger relative to brain size in the solitary species. However, the earlier study did not account for body size effects, and species' relative mushroom body size increases with body size in social Vespidae. Here we extend the previous analysis by measuring the effects of body size variation on brain structure differences between social and solitary vespid wasps. We asked whether total brain volume was greater relative to body size in the solitary species, and whether relative mushroom body size was greater in solitary species, after accounting for body size effects. Both total brain volume and relative mushroom body volume were significantly greater in the solitary species after accounting for body size differences. Therefore, body size allometry did not explain the solitary versus social species differences in brain structure. The evolutionary transition from solitary to social behavior in Vespidae was accompanied by decreases in total brain size and in relative mushroom body size.

    View details for DOI 10.1007/s00359-019-01374-w

    View details for Web of Science ID 000495191100001

    View details for PubMedID 31705196

  • Mannitol ingestion causes concentration-dependent, sex-biased mortality in adults of the fruit fly (Drosophila melanogaster) PLOS ONE Fiocca, K., Barrett, M., Waddell, E. A., Viveiros, J., McNair, C., O'Donnell, S., Marenda, D. R. 2019; 14 (5): e0213760


    Mannitol, a sugar alcohol used in commercial food products, has been previously shown to induce sex-biased mortality in female Drosophila melanogaster when ingested at a single concentration (1 M). We hypothesized that sex differences in energy needs, related to reproductive costs, contributed to the increased mortality we observed in females compared to males. To test this, we compared the longevity of actively mating and non-mating flies fed increasing concentrations of mannitol. We also asked whether mannitol-induced mortality was concentration-dependent for both males and females, and if mannitol's sex-biased effects were consistent across concentrations. Females and males both showed concentration-dependent increases in mortality, but female mortality was consistently higher at concentrations of 0.75 M and above. Additionally, fly longevity decreased further for both sexes when housed in mixed sex vials as compared to single sex vials. This suggests that the increased energetic demands of mating and reproduction for both sexes increased the ingestion of mannitol. Finally, larvae raised on mannitol produced expected adult sex ratios, suggesting that sex-biased mortality due to the ingestion of mannitol occurs only in adults. We conclude that sex and reproductive status differences in mannitol ingestion drive sex-biased differences in adult fly mortality.

    View details for DOI 10.1371/journal.pone.0213760

    View details for Web of Science ID 000469759100008

    View details for PubMedID 31150400

    View details for PubMedCentralID PMC6544200

  • Adult nutrition and reproductive physiology: a stable isotope analysis in a eusocial paper wasp (Mischocyttarus mastigophorus, Hymenoptera: Vespidae) BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY O'Donnell, S., Fiocca, K., Campbell, M., Bulova, S., Zelanko, P., Velinsky, D. 2018; 72 (6)
  • Erythritol ingestion impairs adult reproduction and causes larval mortality in Drosophila melanogaster fruit flies (Diptera: Drosophilidae) JOURNAL OF APPLIED ENTOMOLOGY O'Donnell, S., Baudier, K., Fiocca, K., Marenda, D. R. 2018; 142 (1-2): 37-42

    View details for DOI 10.1111/jen.12409

    View details for Web of Science ID 000419830900005

  • Size constraints and sensory adaptations affect mosaic brain evolution in paper wasps (Vespidae: Epiponini) BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY O'Donnell, S., Bulova, S. J., Barrett, M., Fiocca, K. 2018; 123 (2): 302-310
  • Caste differences in the mushroom bodies of swarm-founding paper wasps: implications for brain plasticity and brain evolution (Vespidae, Epiponini) BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY O'Donnell, S., Bulova, S. J., DeLeon, S., Barrett, M., Fiocca, K. 2017; 71 (8)