- Author: Kathy Keatley Garvey
His topic is""Do Positive Species Interactions Promote Invasions? The Role of Ant-Hemipteran Mutualisms in Ant Invasions." The seminar takes place from 12:10 to 1 p.m. in 122 Briggs. Host is assistant professor Brian Johnson, who coordinates the winter quarter seminars. Plans call for video-recording the seminar for later posting on UCTV.
"Mutualistic and facilitative interactions encourage the establishment and spread of introduced species to a degree that is currently underappreciated," said Holway in his abstract. "Commonly formed mutualistic associations between introduced ants and honeydew-producing Hemiptera alter the abundance and behavior of these ants in ways that directly contribute to their ecological success. Our research centers on the red imported fire ant (Solenopsis invicta) and the Argentine ant (Linepithema humile), the two most widespread, abundant and ecologically damaging introduced ants in North America"
"As with most interactions between ants and honeydew-producing Hemiptera, partnerships that involve either S. invicta or L. humile tend to be general, with the ants commonly and opportunistically forming associations with a wide variety of aphids, scales, and mealybugs (including both native and non-native species). Using a combination of experimental approaches and isotopic analyses, our research demonstrates that assimilation of carbohydrate-rich resources (e.g., honeydew, nectar) elevates levels of colony growth and affects worker behavioral traits in ways that likely contribute to competitive performance."
"Intense interspecific competition in their native Argentina constrains the ability of S. invicta and L. humile to control honeydew-producing Hemiptera (and other accessible sources of carbohydrates), whereas these invaders dominate these resources in their introduced US range. Consistent with this strong pattern, nitrogen isotopic data reveal that S. invicta and L. humile from populations in the US occupy a lower trophic position compared to that occupied by these species in Argentina. Given the high densities often achieved by introduced ants, their interactions with honeydew-producing insects may represent an important and largely underappreciated form of herbivory."
Holway advanced to professor in the Division of Biological Sciences at UC San Diego in 2011. He has served as director of the UC San Diego Natural Reserve System since 2010.
He is the author of more than 60 peer-reviewed publications, including research in Ecological Entomology, Oecologia, Proceedings of the National Academy of Sciences, Ecology, Insectes Sociaux, Molecular Ecology, and Journal of Experimental Biology. Among the most recent:
LeVan, K.E., K-L.J.Hung, K.R. McCann, J. Ludka & D.A. Holway. Floral visitation by the Argentine ant reduces pollinator visitation and seed set in the coast barrel cactus, Ferocactus viridescens. Oecologia, In press.
Yoo, H.J., M.C. Kizner & D.A. Holway. Ecological effects of multi-species, ant-hemipteran mutualisms in citrus. Ecological Entomology 38:505-514.
Wilder, S.M., T.R. Barnum, D.A. Holway, A.V. Suarez & M.D. Eubanks. 2013. Introduced fire ants can exclude native ants from critical mutualist-provided resources. Oecologia 172:197-205.
Wilder, S.M., D.A. Holway, A.V. Suarez, E.G. LeBrun & M.D. Eubanks. 2011. Intercontinental differences in resource use reveal the importance of mutualisms in fire ant invasions. Proceedings of the National Academy of Sciences 108:20639-20644.
Yoo, H.J. & D.A. Holway. 2011. Context-dependence in an ant-aphid mutualism: direct effects of tending intensity on aphid performance. Ecological Entomology 36:450-458.
Wilder, S.M., D.A. Holway, A.V. Suarez & M.D. Eubanks. 2011. Macronutrient content of plant-based food affects growth of a carnivorous arthropod. Ecology 92:325-332.
LeBrun, E.G., M. Moffett & D.A. Holway. 2011. Convergent evolution of levee building behavior among distantly related ant species in a flood-plain ant assemblage. Insectes Sociaux 58:263-269.
Wilson, E.E. & D.A. Holway. 2010. Multiple mechanisms underlie displacement of solitary Hawaiian Hymenoptera by an invasive social wasp. Ecology 91:3294-3302.
Wilson, E.E, C. Sidhu, K.E. LeVan & D.A. Holway. 2010. Pollen foraging behavior of solitary Hawaiian bees revealed through molecular pollen analysis. Molecular Ecology 19: 4823-4829.
Menke,S.B., A.V. Suarez, C.V. Tillberg, C.T. Chou & D.A. Holway. 2010. Trophic ecology of the invasive Argentine ant: spatio-temporal variation in resource assimilation. Oecologia 164:763-773.
Wilson, E.E., C.V. Young & D.A. Holway. 2010. Predation or scavenging? Thoracic muscle pH and rates of water loss reveal cause of death in arthropods. Journal of Experimental Biology 213:2640-2646.
Kay, A.D., T. Zumbusch, J.L. Heinen, T.C. Marsh, & D.A. Holway. 2010. Nutrition and interference competition have interactive effects on the behavior and performance of Argentine ants. Ecology 91:57-64.