Takayuki Ohgushi

Effects of resource distribution on animal-plant interactions

M.D. Hunter and P.W. Price, Introduction: Plants as a Variable Resource Base for Animals. M.C. Rossiter, The Impact of Resource Variation on Population Quality in Herbivorous Insects: A Critical Aspect of Population Dynamics. R.S. Ostfeld, Small Mammal Herbivores in a Patchy Environment: Individual Strategies and Population Responses. A.E. Weis and D.R. Campbell, Plant Genotype: A Variable Factor in Insect-Plant Interaction. B.J. Rathcke, Nectar Distributions, Pollinator Behavior, and Plant Reproductive Success. P.W. Price, Plant Resources as the Mechanistic Basis for Insect Herbivore Population Dynamics. J.C. Schultz, Factoring Natural Enemies into Plant Tissue Availability to Herbivores. T. Ohgushi, Resource Limitation on Insect Herbivore Populations. J.R. Karr, M. Dionne, and I. Schlosser, Bottom-Up versus Top-Down Regulation of Vertebrate Populations: Lessons from Birds and Fish. M.D. Hunter, Interactions Within Herbivore Communities Mediated by the Host Plant: The Keystone Herbivore Concept. D.W. Roubik, Loose Niches in Tropical Communities: Why Are There So Few Bees and So Many Trees? T.H. Fleming, How Do Fruit-and-Nectar Feeding Birds and Mammals Track Their Food Resources? T. Inoue and M. Kato, Inter-and Intraspecific Morphological Variation in Bumblebee Species, and Competition in Flower Utilization. J.M. Scriber and R.C. Lederhouse, The Thermal Environment as a Resource Dictating Patterns of Feeding Specialization of Insect Herbivores. Each chapter includes references. Index.

Ecological communities: Plant mediation in indirect interaction webs

Preface Part I. Introduction: 1. Indirect interaction webs: an introduction Takayuki Ohgushi, Timothy P. Craig and Peter W. Price Part II. Interaction Linkages Produced by Plant-mediated Indirect Effects: 2. Plant-mediated interactions in herbivorous insects: mechanisms, symmetry, and challenging the paradigms of competition past Robert F. Denno and Ian Kaplan 3. Going with the flow: plant vascular systems mediate indirect interactions between plants, insect herbivores and hemi-parasitic plants Susan E. Hartley, Kathy A. Bass and Scott N. Johnson 4. Plant-mediated effects linking herbivory and pollination Judith L. Bronstein, Travis E. Huxman and Goggy Davidowitz 5. Trait-mediated indirect interactions, density-mediated indirect interactions and direct interactions between mammalian and insect herbivores Jose M. Gomez and Adela Gonzales-Megias 6. Insect-mycorrhizal interactions: patterns, processes and consequences Alan C. Gange Part III. Plant-mediated Indirect Effects in Multitrophic Systems: 7. Plant-mediated interactions between below- and aboveground processes: decomposition, herbivory, parasitism and pollination Katja Poveda, Ingolf Steffan-Dewenter, Stefan Scheu and Teja Tscharntke 8. Bottom-up cascades induced by fungal endophytes in multitrophic systems Enrique J. Chaneton and Marina Omacini 9. Ecology meets plant physiology: herbivore-induced plant responses and their indirect effects on arthropod communities Maurice W. Sabelis, Junji Takabayashi, Arne Janssen, Merijn Kant, Michiel van Wijk, Beata Sznajder, Nayanie Aratchige, Izabela Lesna, Belen Belliure and Robert C. Schuurink Part IV. Plant-mediated Indirect Effects on Communities and Biodiversity: 10. Nontrophic, indirect interaction webs of herbivorous insects Takayuki Ohgushi 11. Effects of arthropods as physical ecosystem engineers on plant-based trophic interaction webs Robert J. Marquis and John T. Lill 12. Host plants mediated ant-aphid mutualisms and their effects on community structure and diversity Gina M. Wimp and Thomas G. Whitham 13. Biodiversity is related to indirect interactions among species of large effect Joseph K. Bailey and Thomas G. Whitham Part V. Evolutionary Consequences of Plant-mediated Indirect Effects: 14. Evolution of plant-mediated interactions among natural enemies Timothy P. Craig 15. Linking ecological and evolutionary change in multitrophic interactions: assessing the evolutionary consequences of herbivore-induced changes in plant traits David M. Althoff Part VI. Synthesis: 16. Indirect interaction webs propagated by herbivore-induced changes in plant traits Takayuki Ohgushi, Timothy P. Craig and Peter W. Price.To gain a more complete understanding of plant-based ecological community structure requires knowledge of the integration of direct and indirect effects in plant–herbivore systems. Trait modification of plants as a result of herbivory is very common and widespread in terrestrial plants, and this initiates indirect interactions between organisms that utilize the same host plant. This book argues that food webs by themselves are inadequate models for understanding ecological communities, because they ignore important indirect, nontrophic links. This subject is of great importance in understanding not only community organization but also in identifying the underlying mechanisms of maintenance of biodiversity in nature. This book will be an invaluable resource for researchers and graduate students interested in community and population ecology, evolutionary biology, biodiversity, botany, and entomology.

Herbivore‐induced indirect interaction webs on terrestrial plants: the importance of non‐trophic, indirect, and facilitative interactions

One of the most important issues in ecology is understanding the causal mechanisms that shape the structure of ecological communities through trophic interactions. The focus on direct, trophic interactions in much of the research to date means that the potential significance of non‐trophic, indirect, and facilitative interactions has been largely ignored in traditional food webs. There is a growing appreciation of the community consequences of such non‐trophic effects, and the need to start including them in food web research. This review highlights how non‐trophic, indirect, and facilitative interactions play an important role in organizing the structure of plant‐centered arthropod communities. I argue that herbivore‐induced plant responses, insect ecosystem engineers, and mutualisms involving ant–honeydew‐producing insects all generate interaction linkages among insect herbivores, thereby producing complex indirect interaction webs on terrestrial plants. These interactions are all very common and widespread on terrestrial plants, in fact they are almost ubiquitous, but these interactions have rarely been included in traditional food webs. Finally, I will emphasize that because the important community consequences of these non‐trophic and indirect interactions have been largely unexplored, it is critical that indirect interaction webs should be the focus of future research.

Bottom-up trophic cascades and material transfer in terrestrial food webs

In contrast to top-down trophic cascades, few reviews have appeared of bottom-up trophic cascades. We review the recent development of research on bottom-up cascades in terrestrial food webs, focusing on tritrophic systems consisting of plants, herbivorous insects, and natural enemies, and attempt to integrate bottom-up cascade and material transfer among trophic levels. Bottom-up cascades are frequently reported in various tritrophic systems, and are important to determine community structure, population dynamics, and individual performance of higher trophic levels. In addition, we highlight several features of bottom-up cascades. Accumulation or dilution of plant nutritional and defensive materials by herbivorous insects provides a mechanistic base for several bottom-up cascades. Such a stoichiometric approach has the potential to improve our understanding of bottom-up cascading effects in terrestrial food webs. We suggest a future direction for research by integration of bottom-up cascades and material transfer among trophic levels.

A reproductive tradeoff in an herbivorous lady beetle: egg resorption and female survival

A reproductive tradeoff between current egg production and subsequent survival in a lady beetle, Epilachna niponica, a specialist herbivore on a thistle, Cirsium kagamontanum, was investigated at the two study sites, A and F. Survival of reproductive females decreased consistently from early May until mid-June, but apparently increased thereafter. In contrast, males showed a consistent decrease in survival throughout the reproductive season, without any sign of recovery. Dissection of ovaries of sampled females revealed that egg resorption increased late in the reproductive season, coincident with increased female survival. Reproductive females stopped oviposition immediately after a large flood in 1979 at site F. Two weeks after the habitat perturbation, females resumed oviposition in response to a flush of new leaves on damaged plants. Female survival sharply increased during the nonoviposition period, and declined when egg-laying resumed. Approximately 40% of long-lived reproductive females at site F survived up to the following reproductive season in the next year. Also, some of these long-lived females were observed ovipositing in the following reproductive season. The long-lived reproductive females which had previously invested in reproduction survived equally well as newly emerged females which had not reproduced in summer. These results suggest that there is a reproductive tradeoff between current egg production and subsequent survival. Egg resorption may be an adaptive ovipositional response to habitat perturbation such as flooding, which considerably reduces offspring fitness due to absolute shortage of food. Also, increased female survival accompanied by egg resorption enhances the likelihood of the future oviposition in the second reproductive season, thereby increasing a females lifetime reproductive success.

Studies on the population dynamics of a thistle-feeding lady beetle,Henosepilachna pustulosa (Kôno) in a cool temperate climax forest

1. A field study was carried out on the population dynamics of a thistle-feeding lady beetle,Henosepilachna pustulosa (Kono) living in a cool temperature climax forest in northern Kyoto Prefecture, central Japan. 2. Intensive marking, release and recapture program was carried out to estimate the adult population parameters by usingJolly-Seber method. 3. Sampling ratio was around 50%. Marking ratio rapidly rised as the census progressed and approached to 100%. 4. Sex ratio (% ♀) was 63–69% in both overwintered and new adults. 5. Daily survival rate was as high as 0.95 or more and constant throughout the season. Adult longevity in the spring was longer than 40 days. 6. Reproductive rate i. e., the ratio of the number of newly emerged adults in a given generation to that of overwintered adults in the preceding generation, is very small, ranging 1–3, whereas winter survival is higher than 50%, consequently the size of populations in the study area remain in a remarkably constant size and it never reached a level where intraspesific competition occurred. 7. The population characteristics ofH. pustulosa are compared with those of the two closely related species,H. vigintioctopunctata andH. vigintioctomaculata, which are the pests ofSolanaceous crops.Hp is moreK-strategic than the two pest species.

Trait-Mediated Indirect Interactions: Ecological and Evolutionary Perspectives

List of contributors Foreword Preface 1. Introduction Part I. Community: 2. Perspective: kinds of trait-mediated indirect effects in ecological communities: a synthesis 3. Consequences of trait changes in host-parasitoid interactions in insect communities 4. The impact of trait-mediated indirect interactions in marine communities 5. Trait-mediated indirect interactions in size-structured populations: causes and consequences for species interactions and community dynamics 6. Trait-mediated effects, density dependence, and the dynamic stability of ecological systems 7. Plant effects on herbivore-enemy interactions in natural systems 8. The implications of adaptive prey behavior for ecological communities: a review of current theory 9. Community consequences of phenotypic plasticity of terrestrial plants: herbivore-initiated bottom-up trophic cascades 10. Model-based, response surface approaches to quantifying indirect interactions Part II. Coevolution: 11. Perspective: trait-mediated indirect interactions and the coevolutionary process 12. Evolutionary indirect effects: examples from introduced plant and herbivore interactions 13. Indirect evolutionary interactions in a multi-trophic system 14. The role of trait-mediated indirect interactions for multispecies plant-animal mutualisms 15. Consequences of trait evolution in a multi-species system Part III. Ecosystem: 16. Perspective: interspecific indirect genetic effects (IIGEs): linking genetics and genomics to community ecology and ecosystem processes 17. Species functional traits, trophic control, and the ecosystem consequences of adaptive foraging in the middle of food chains 18. Effects of herbivores on terrestrial ecosystem processes: the role of trait mediated indirect effects 19. Functional and heritable consequences of plant genotype on community composition and ecosystem processes 20. Microbial mutualists and biodiversity in ecosystems 21. Integrating trait-mediated effects and non-trophic interactions in the study of biodiversity and ecosystem functioning Part IV. Applied Ecology: 22. Perspective: consequences of trait-mediated indirect interactions for biological control of plant pests 23. Natural enemy functional identity, trait-mediated interactions, and biological control 24. Trait-mediated effects modify patch-size density relationships in insect herbivores and parasitoids 25. Plasticity and trait-mediated indirect interactions among plants 26. Climate change, phenology, and the nature of consumer-resource interactions: advancing the match/mismatch hypothesis 27. Coda Index.

Preference and performance are correlated in the spittlebug Aphrophora pectoralis on four species of willow

Abstract 1. There was a positive correlation between oviposition and feeding preferences and offspring performance in the spittlebug Aphrophora pectoralis Matsumura (Homoptera: Cercopoidea, Aphrophoridae) on four species of willow Salix sp. (Salicaceae) growing near Sapporo, Japan. Spittlebugs preferred rapidly growing shoots where performance was highest.

Plant genotypic diversity increases population size of a herbivorous insect

It is critical to incorporate the process of population dynamics into community genetics studies to identify the mechanisms of the linkage between host plant genetics and associated communities. We studied the effects of plant genotypic diversity of tall goldenrod Solidago altissima on the population dynamics of the aphid Uroleucon nigrotuberculatum. We found genotypic variation in plant resistance to the aphid in our experiments. To determine the impact of plant genotypic diversity on aphid population dynamics, we compared aphid densities under conditions of three treatments: single-genotype plots, mixed-genotype plots and mixed-genotype-with-cages plots. In the latter treatment plants were individually caged to prevent natural enemy attack and aphid movement among plants. The synergistic effects of genotypes on population size were demonstrated by the greater aphid population size in the mixed-genotype treatment than expected from additive effects alone. Two non-exclusive hypotheses are proposed to explain this pattern. First, there is a source–sink relationship among plant genotypes: aphids move from plant genotypes where their reproduction is high to genotypes where their reproduction is low. Second, natural enemy mortality is reduced in mixed plots in a matrix of diverse plant genotypes.

Preference-performance linkage in a herbivorous lady beetle: consequences of variability of natural enemies

Abstract We investigated the relationship between oviposition preference and offspring performance in a herbivorous lady beetle Epilachna pustulosa on two co-occurring plant species, thistle Cirsium kamtschaticum and blue cohosh Caulophyllum robustum, in 1994 and 1995. The relative importance of bottom-up effects by host plants and top-down effects by natural enemies on offspring performance were determined using field and laboratory experiments. In both years, egg density on blue cohosh was significantly higher than on thistle. A laboratory experiment demonstrated that larval survival from hatching to adult emergence was significantly higher, and developmental period shorter when larvae were reared on blue cohosh compared to thistle. The positive preference-performance linkage varied between years in the field. Top-down effects had a different impact on larval survival on the two host plant species. Arthropod predators, a lady beetle Harmonia axyridis and an earwig Forficula mikado, considerably depressed immature survival on thistle, while they were negligible on blue cohosh. Although the lack of effective predation increased larval survival on blue cohosh, it led to defoliation due to increased larval feeding late in the season. Because of severe intraspecific competition, old larvae had significantly lower survival on blue cohosh than on thistle. In 1994, as larval survival decreased due to defoliation on blue cohosh, the overall survival rate was significantly higher on thistle than on blue cohosh. This survival pattern was opposite to that found in the laboratory experiment. In contrast, in 1995, the increase in predatory lady beetles on thistle caused greater larval mortality. Thus, the overall survival was significantly lower on thistle than on blue cohosh, although severe intraspecific competition occurred on blue cohosh as it had in 1994. Consequently, the offspring performance on the two host plants is largely determined by the relative importance of arthropod predation determining larval survival on thistle and host plant defoliation reducing late larval survival on blue cohosh. These results indicate the important role of spatial and temporal variability of natural enemies on the preference-performance linkage of herbivorous insects.