Temperature as a key driver of ecological sorting among invasive pest species in the tropical Andes.

Invasive species are a major threat to the sustainable provision of ecosystem products and services, both in natural and agricultural ecosystems. To understand the spatial arrangement of species successively introduced into the same ecosystem, we examined the tolerance to temperature and analyzed the field distribution of three potato tuber moths (PTM, Lepidoptera: Gelechiidae), that were introduced in Ecuador since the 1980s. We studied physiological responses to constant temperatures of the three PTM species under laboratory conditions and modeled consequences for their overall population dynamics. We then compared our predictions to field abundances of PTM adults collected in 42 sites throughout central Ecuador. Results showed that the three PTM species differed with respect to their physiological response to temperature. Symmetrischema tangolias was more cold tolerant while Tecia solanivora had the highest growth rates at warmer temperatures. Phthorimaea operculella showed the poorest physiological performance across the range of tested temperatures. Overall, field distributions agree with predictions based on physiological experiments and life table analyses. At elevations >3000 m, the most cold-tolerant species, S. tangolias, was typically dominant and often the only species present. This species may therefore represent a biological sensor of climate change. At low elevations (<2700 m), T. solanivora was generally the most abundant species, probably due to its high fecundity at high temperatures. At mid elevations, the three species co-occurred, but P. operculella was generally the least abundant species. Consistent with these qualitative results, significant regression analyses found that the best predictors of field abundance were temperature and a species x temperature interaction term. Our results suggest that the climatic diversity in agricultural landscapes can directly affect the community composition following sequential invasions. In the tropical Andes, as in other mountain ecosystems, the wide range of thermal environments found along elevational gradients may be one reason why the risks of invasion by successively introduced pest species could increase in the near future. More data on potential biological risks associated with climatic warming trends in mountain systems are therefore urgently needed, especially in developing nations where such studies are lacking.

[1]  D. Wilson,et al.  Seasonal temperatures and the phenology of greedy scale populations (Homoptera: Diaspididae) on kiwifruit vines in New Zealand , 1994 .

[2]  H. Pulliam On the relationship between niche and distribution , 2000 .

[3]  I. Hodkinson Species response to global environmental change or why ecophysiological models are important: a reply to Davis et al. , 1999 .

[4]  J. Obrycki,et al.  Research Reports: A Computer Program for Calculation and Statistical Comparison of Intrinsic Rates of Increase and Associated Life Table Parameters , 1990 .

[5]  Jörg Samietz,et al.  Temperature effects on egg development of the rosy apple aphid and forecasting of egg hatch , 2006 .

[6]  Brian D. Ripley,et al.  Modern Applied Statistics with S Fourth edition , 2002 .

[7]  J. Régnière,et al.  Risk assessment in the face of a changing environment: gypsy moth and climate change in Utah. , 2007, Ecological applications : a publication of the Ecological Society of America.

[8]  A. Seitz,et al.  Genetic and morphological differentiation of Dikerogammarus invaders and their invasion history in Central Europe , 2002 .

[9]  P. David,et al.  Climatic niche partitioning following successive invasions by fruit flies in La Réunion. , 2006, The Journal of animal ecology.

[10]  I. Hodkinson,et al.  Terrestrial insects along elevation gradients: species and community responses to altitude , 2005, Biological reviews of the Cambridge Philosophical Society.

[11]  T. Keasar,et al.  Spatial and temporal dynamics of potato tuberworm (Lepidoptera: Gelechiidae) infestation in field-stored potatoes. , 2005, Journal of economic entomology.

[12]  M. Cadotte,et al.  Life‐history correlates of plant invasiveness at regional and continental scales , 2005 .

[13]  B. Bentz,et al.  Comparison of three models predicting developmental milestones given environmental and individual variation , 2004, Bulletin of mathematical biology.

[14]  J. Bale,et al.  Climatic signals in the life histories of insects: the distribution and abundance of heather psyllids (Strophingia spp.) in the UK , 1999 .

[15]  X. Cerdá,et al.  Critical thermal limits in Mediterranean ant species: trade‐off between mortality risk and foraging performance , 1998 .

[16]  J. R. Ott,et al.  Interspecific interactions in phytophagous insects : competition reexamined and resurrected , 1995 .

[17]  David Tilman,et al.  Biodiversity as a barrier to ecological invasion , 2002, Nature.

[18]  Harold A. Mooney,et al.  Invasive species in a changing world , 2000 .

[19]  R. Shine,et al.  ECOLOGICAL CONSEQUENCES OF AGONISTIC INTERACTIONS IN LIZARDS , 2005 .

[20]  P. McEvoy Niche Partitioning in Spittlebugs (Homoptera: Cercopidae) Sharing Shelters on Host Plants , 1986 .

[21]  Peter Turchin,et al.  Complex Population Dynamics , 2003 .

[22]  Steven E. Naranjo,et al.  Mortality dynamics and population regulation in Bemisia tabaci , 2005 .

[23]  D. Rajagopal,et al.  Distribution, biology, ecology and management of potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae): A review , 1992 .

[24]  Wolfgang W. Weisser,et al.  The importance of adverse weather conditions for behaviour and population ecology of an aphid parasitoid , 1997 .

[25]  P. Sharpe,et al.  Reaction kinetics of poikilotherm development. , 1977, Journal of theoretical biology.

[26]  J. Kiesecker,et al.  POTENTIAL MECHANISMS UNDERLYING THE DISPLACEMENT OF NATIVE RED‐LEGGED FROGS BY INTRODUCED BULLFROGS , 2001 .

[27]  J. Kroschel,et al.  A Temperature-Based Simulation Model for the Potato Tuberworm, Phthorimaea operculella Zeller (Lepidoptera; Gelechiidae) , 2004 .

[28]  Tiina Ylioja,et al.  Impact of minimum winter temperatures on the population dynamics of Dendroctonus frontalis. , 2007, Ecological applications : a publication of the Ecological Society of America.

[29]  A. Suarez,et al.  Patterns of spread in biological invasions dominated by long-distance jump dispersal: Insights from Argentine ants. , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[30]  Á. Barragán,et al.  Tecia solanivora, a serious biological invasion of potato cultures in South America , 2003 .

[31]  S. Teck,et al.  Larval development rate predicts range expansion of an introduced crab , 2007 .

[32]  Jane Uhd Jepsen,et al.  Shifting altitudinal distribution of outbreak zones of winter moth Operophtera brumata in sub‐arctic birch forest: a response to recent climate warming? , 2007 .

[33]  A. Gutierrez,et al.  Overwintering in the cabbage root fly Delia radicum : a dynamic model of temperature-dependent dormancy and post-dormancy development , 1997 .

[34]  J. L. Parra,et al.  Very high resolution interpolated climate surfaces for global land areas , 2005 .

[35]  P. Chesson,et al.  Community ecology theory as a framework for biological invasions , 2002 .

[36]  D. Richardson,et al.  What attributes make some plant species more invasive , 1996 .

[37]  E. García‐Berthou,et al.  Profiling invasive fish species: the importance of phylogeny and human use , 2005 .

[38]  Cédric M. John Plotting and analyzing data trends in ternary diagrams made easy , 2004 .

[39]  T. M. Bezemer,et al.  Herbivory in global climate change research: direct effects of rising temperature on insect herbivores , 2002 .

[40]  Shrub succession and invasibility in a New zealand montane grassland , 1998 .

[41]  R. Ricklefs,et al.  Distributions of exotic plants in eastern Asia and North America. , 2006, Ecology letters.

[42]  O. Dangles,et al.  The Importance of Detritivore Species Diversity for Maintaining Stream Ecosystem Functioning Following the Invasion of a Riparian Plant , 2002, Biological Invasions.

[43]  S. Dupas,et al.  Genetic bottleneck in invasive species: the potato tuber moth adds to the list , 2008, Biological Invasions.

[44]  J. Lawton,et al.  Individualistic species responses invalidate simple physiological models of community dynamics under global environmental change , 1998 .

[45]  Robert A. Cheke,et al.  Brown locust outbreaks and climate variability in southern Africa , 2002 .

[46]  A. Huusko,et al.  Niche characteristics explain the reciprocal invasion success of stream salmonids in different continents , 2007, Proceedings of the National Academy of Sciences.

[47]  J. Kroschel,et al.  An improved method to determine the biological activity (LC50) of the granulovirus PoGV in its host Phthorimaea operculella , 2005 .

[48]  C. Krebs Ecology: The Experimental Analysis of Distribution and Abundance , 1973 .

[49]  R. Bradley,et al.  20th Century Climate Change in the Tropical Andes , 2003 .

[50]  J. Bale,et al.  Thermal Environments of Arctic Soil Organisms during Winter , 1995 .

[51]  A. Davis,et al.  Synergistic effects associated with climate change and the development of rocky shore molluscs , 2005 .

[52]  A search for 22‐GHz water masers within the giant molecular cloud associated with RCW 106 , 2007, astro-ph/0702673.