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R. L. Kitching
Cambridge University Press, New York
2000, xiii + 431 pp. Hardback
Price: $100.00, ISBN: 0-521-77316-4
Roger Kitching is one of those patient and thoughtful biologists who likes to focus on a single biological system and a single conceptual framework for an entire career and amplify on that system and framework through long-term, serious study. This book summarizes that process and, in part, is autobiographical because some of the text is narrative and much of it is based on his work. The study system is ‘phytotelmata,’ a word rooted in Greek meaning ‘plant ponds’ with reference to small volumes of water held in plant structures. The conceptual framework is food webs–how organisms interact in communities as they divvy up food resources. Kitching writes sentimental anecdotes in the form of diary entries as he attempts to excite the reader about the subject matter. He does a good job of combining into one book his own experiences, natural history, quantitative ecology, and organismal biology.
Entomologists who are interested in aquatic insects or population and community ecology of arthropods will like this book because the phytotelmata are highly diverse aquatic habitats such as tree holes, pitcher plants, bamboo internodes, leaf bracts, fallen coconut husks, and so forth; and they contain a diverse array of arthropods and occur in both temperate and tropical areas. Many mosquito biologists cut their academic teeth on phytotelmata. Some experts estimate that 40% of the 3,000+ species of mosquitoes have phytotelmata as larval habitats. Other insect groups that have radiated into these habitats include scirtid beetles, ceratopogonid midges, psychodids, chironomids, and other arthropods as well as other invertebrates and some vertebrates. Thus, phytotelmata are fine study systems for examining such ecological phenomena as food webs, which is the point of this book–how do so many individuals of such a diverse array of arthropods and other organisms manage to coexist in the water of these small habitats? There also is a good deal of botany in this book, but it is not overwhelming even if you are not familiar with Darlingtonia, Nepenthes, Sarracenia, and tank bromeliads; and the author provides a good botanical section and a long table with a list of plant species with leaf axil phytotelmata. Unfortunately, the book does suffer from a lack of good illustrations, showing only one set of black and white photos of Nepenthes pitchers and many diagrammatic line drawings. For $100, one would expect much better illustrations including color photos. While preparing this review, I reached for my copy of Shigeo Kurata’s Nepenthes of Mount Kinabalu (Kurata 1976) both to recall the beauty of these plants and to compare the illustrations between the two books (Kurata’s line drawings are more informative, and his booklet has several color photos).
Part I. Kitching organizes his book into five sections of 14 chapters, and he provides a figure that shows the book’s organization and how different sections relate to each other. Part I deals with the botany, the metazoan fauna of container habitats, and the physicochemical nature of containers. This section is comprehensive, but very early on it is apparent that Kitching tends to ignore the functional feeding group terms and classifications developed after careful thought by other writers (R. W. Merritt and K. W. Cummins come to mind) in lieu of his own terms. Thus, an unknowing reader might think that terms like ‘macrodecomposer’ or ‘microsaprophage’ are formal and useful, whereas aquatic entomologists might prefer terms based on actual mouth part morphology, feeding behavior, and predominant food type, such as ‘shredder’ or ‘collector-gatherer.’ My point here leads to one of my chief criticisms of Kitching’s book: Kitching often infers the biological attributes of particular organisms and then constructs food webs from these inferences. In fact, attributes such as the feeding behaviors and modalities of the immature stages of many arthropods that inhabit phytotelmata are poorly known from a behavioral standpoint and from the lack of studies on actual gut contents or ingested food items. Does anyone really know if Clogmia larvae (Diptera: Psychodidae), for example, are "microsaprophages" (Fig. 5.2, p. 96)? And what function do the funny looking brush-like setae on the mandible of scirtid larvae actually have-are they sweepers? These sorts of distinctions are not minor when the whole thesis of the book depends on them because you cannot really construct an accurate food web without the information. In a sense, the food webs constructed in the book are second-order inferences because they are based first on inferences about the feeding mechanisms, morphology, and behavior.
Part II. Part II consists of theory of food webs and methods (including data reduction and statistical summarization) for constructing them. From the standpoint of methodology, Kitching clearly favors mensurative (non-experimental) sampling-based studies over interventionist (or experimental) studies for food web analysis, and he gives not much more than lip service to experimental microcosm work even though phytotelmata are natural microcosms and can be manipulated and very often simulated in the laboratory or field. I am not convinced that a sampling program will provide an adequate representation of the full array of organisms from the phytotelms for a mensurative study or will reveal the subtle processes and interactions that occur within them. Kitching does not address quantitative sampling per se and very often refers to his standard method of making some hand-dips into the containers, removing the organisms, and then commencing with sorts and counts. Speaking from experience (and admittedly as somebody who has stopped at the supermarket to buy a turkey baster on his way to the tree hole route), this method would undersample organisms like scirtid larvae, which tend to cling, or Culicoides larvae, which tend to burrow. A more careful discussion of the need to sample properly by destructive means, to rinse the container, and to sieve material through decreasing mesh sizes for separation would be better. In one section the author describes removing whole Nepenthes pitchers and taking them en toto with contents to the laboratory for sorting. But rarely do investigators have this luxury, certainly not with tree holes, bamboo internodes, or protected plants. Readers may find the painstaking tree hole sampling procedures described by Phil Lounibos of interest (Lounibos 1983, Lounibos et al. 1997). Kitching advocates counts of individuals of each taxon for food web construction when energy flow through the web might be better illustrated if units of biomass were used. This analysis would improve upon Kitching’s method of scaling abundances of organisms into quartiles because the latter still does not provide a common scale for equivalents of, say, rat-tailed maggots and midge larvae nor does it account for different instars of the same organism. This book would be supported if it went into more detail on the several recent mensurative and manipulative studies in diverse phytotelm communities that uncovered so-called processing chain commensalisms (positive trophic interactions), such as those by S. Heard, S. Naeem, C. Paradise, W. Bradshaw and colleagues, for example. The phrase ‘processing chain commensalism’ does not appear in the index, which is strange considering it fits well within the topic of this book.
Kitching basically ignores the microorganisms in phytotelmata, yet it is likely that they have an absolutely central role in processing organic detritus, in nutrient cycling, and in providing the bulk and essential foods and nutrients for the arthropods. The problem is that microbes are a tough nut to crack methodologically, thus Kitching basically equates them to the detritus in the total organic pool. The microorganisms associated with the detrital material convert it to palatable and more nutritious food items. There is a large literature on microbe/detritus interactions in aquatic systems. Thus, the actual resource base that supports the interacting organisms in the food webs Kitching constructs is inaccurately described. His idea is that the material decomposes from large particulate organic matter to smaller particles, such as suspended debris and microorganisms, but, very likely, the large particulate material is rapidly colonized by microbes once it falls into the phytotelms. I wonder what the food web diagrams would look like if the biomass of bacteria, protists, fungi, and algae associated with the detrital pool and the water column included. Chapter 6 in Part II goes into the details of food web patterns and processes. Here the author nicely presents information on geographic and temporal scales, including evolutionary and geological time, and presents a series of hypotheses and predictions that form the framework for his analysis.
Parts III-V. Part III proceeds with a series of vignettes into which the material from Part II is woven. Kitching shows how his methodology, data reduction methods, and derived food web variables have been used in different settings and for different types of phytotelms. I enjoyed this section because of the detail, which is a lot but not excessive. Part IV is the section I liked the most, in part, I suppose, because I am familiar with several of the studies that Kitching uses to make his points, and with the people who did the work, and also because Kitching does well in making a synthesis of this work with ecological trends of thought. For example, he points out the seminal work of Bradshaw and Holzapfel (1983) in which study a mosquito predator in tree holes, Toxorhynchites rutilus, mediated non-equilibrium coexistence of an assemblage of other mosquito species in the tree hole community of northern Florida. It shows how a basic sampling study in phytotelmata can address an issue of fundamental ecological concern. At this point, the thesis of the book is open to some criticism, as Kitching obviously has a bias toward a biotic factor (trophic interactions) as the primary determinant of extant community structure in phytotelms. Yet several studies indicate that abiotic or physical factors are very important in community structure. For example, J. Kingsolver (Kingsolver 1979) has shown that distribution of Sarracenia pitcher plants and the amount of insolation they receive interact with hydric regime and affect abundance and distribution of the pitcher inhabitants (mainly, larvae of the mosquito Wyeomyia smithii and of the midge Metriocnemus knabi). As another example, R. Copeland (Copeland and Craig 1989, 1990) showed that the type of tree hole water influenced the ability of tree hole mosquitoes to overwinter successful in cold climates. Although the mechanisms for the latter observation were not known, the studies suggest that winter temperatures affect mosquito distribution in tree holes. Both of these analyses indicate that factors other than trophic interactions, and physical or abiotic ones at that, affect extant community structure. Part V of the book offers a theoretical construct, the spatio-temporal templet, derived from T.R.E. Southwood’s ideas on habitat as a templet within which ecological strategies of organisms evolve. It involves a synthesis of processes interacting in time and space across both evolutionary and contemporary time scales, and large to small geographic ranges, and aims to delineate how the interactions of these processes ultimately affect food web (and therefore, community) structure.
The last part of the book is an annex presenting information on the range of organisms that can be found in phytotelmata. It consists both of lists and descriptive paragraphs. There are no keys. Entomologists will be impressed with the array of arthropods in these habitats, as well as the presence of oddities such as frogs. The drawings of the arthropods are fine, and there is one line drawing for nearly every group, but a collector will still want to have regional and specialty references handy. This book has a thorough index. I hope the publisher produces a sturdy but cheaper paperback, because $100 for a hardbound edition is pretty expensive for a book with no color illustrations. The graphs look like they were printed on an inkjet and they have lots of rasters, but they usually are readable except when reduced.
Edward D. Walker
Department of Entomology
Michigan State University,
East Lansing, MI 48824
Vol. 47, No.4, Winter 2001
Bradshaw, W. S., and C. H. Holzapfel. 1983. Predator-mediated non-equilibrium coexistence of tree-hole mosquitoes. Oecologia 57: 889-893
Copeland, R. S., and G. B. Craig, Jr. 1989. Winter cold influences the spatial and age distributions of the North American treehole mosquito Anopheles barberi. Oecologia 79: 287-292.
Copeland, R. S., and G. B. Craig, Jr. 1990. Cold-hardiness of tree-hole mosquitoes in the Great Lakes region of the United States. Can. J. Zool. 68: 1307-1314.
Kingsolver, J. G. 1979. Thermal and hydric aspects of environmental heterogeneity in the pitcher plant mosquito. Ecol. Monogr. 49: 357-376.
Kurata, S. 1976. The Nepenthes of Mount Kinabalu. Sabah National Parks Trustees, Malaysia.
Lounibos, L. P. 1983. The mosquito community of treeholes in subtropical Florida, pp. 223-246. In J. H. Frank and L. P. Lounibos (eds.), Phytotelmata: terrestrial plans as host of aquatic insect communities. Plexus, Marlton, NJ.
Lounibos, L. P., R. L. Escher, N. Nishimura, and S. A. Juliano. 1997. Long-term dynamics of a predator used for biological control and decoupling from mosquito prey in a subtropical treehole ecosystem. Oecologia 111: 189-200.