Tropical ecology in miniature

Tropical ecology in miniature

BOOK REVIEWS Portrait of Rothmannia annae, from A Fragile Eden: Portraits of the Endemic Flowering Plants of the Granitic Seychelles, by Rosemary Wis...

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BOOK REVIEWS

Portrait of Rothmannia annae, from A Fragile Eden: Portraits of the Endemic Flowering Plants of the Granitic Seychelles, by Rosemary Wise, Princeton University Press, 1998. £49.50/$75.00 hbk (192 + xvi pages), ISBN 0 691 04817 7.

Tropical ecology in miniature The Butterflies of Costa Rica and their Natural History. Volume II: Riodinidae. by P.J. DeVries Princeton University Press, 1997. $90.00/£70.00 hbk, $29.95/£23.95 pbk (xxvii + 288 pages) ISBN 0 691 02890 7 / 0 691 02889 3

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can’t really compare this book with any other because it is unique – the first complete guide to Riodinidae for any tropical country. Volume I of this work1 (which I reviewed in TREE a decade ago2), treats 540 of the bigger butterflies of Costa Rica. Because the smallest butterflies, the skippers (Hesperiidae), blues and hairstreaks (Lycaenidae), and metalmarks (Riodinidae) contain the majority of tropical butterflies, omissions considerably outnumbered the species included. With the 250 species of Costa Rican Riodinidae in this book, DeVries now partially rectifies the omissions. In this volume, fewer species are treated than in the first, and the illustrations are printed better. The systematics of butterflies in general is in a state of chaos, but Don Harvey’s PhD thesis on the higher systematics of the Riodinidae has added a welcome sense of uniformity to this treatment. However, the major strength of this work is that DeVries has worked in TREE vol. 13, no. 9 September 1998

great depth on the natural history of the antattended Riodinidae, and has personally studied the life histories of many of the species treated here. Overall, I think this is a much better book than its predecessor. Another reason I like the book is that riodinids themselves are incredibly neat. Riodinids have an extraordinary diversity of beautiful colour patterns, especially when compared with the almost uniformly dull hairstreaks or skippers. Their larval behaviour and ecology is fascinating. When I spent formative years in Corcovado National Park in the early 1980s, I was easily distracted from research on Heliconius by some of the riodinids and their caterpillars described in this book. It is surely a thrill for every naturalist to see and record previously unknown interactions and life histories and, via Don Harvey’s thesis, all of our records are now incorporated into this book, together with many new ones from DeVries’s own work. My fascination with riodinids began on my first day in Corcovado. I found what is still my favourite riodinid, Peropthalma, flitting like a tiny mechanical toy from seedling to seedling on the forest floor. At every brief pause, the hypnotic eyespots on her wings stared up unblinkingly. She laid a single egg on a minute plant consisting of only two leaves plus cotyledons open. By finding larger and larger seedlings, I eventually deduced that the hostplant was a small tree, Palicourea guianensis (Rubiaceae). Another group, Eurybia, has similar hypnotic eyespots, but they lurk mostly in the thick undergrowth among Heliconia plants. The adults have enormously long probosces

that they use to rob nectar from hummingbird pollinated flowers. This massive length must be a challenge to development, being very vulnerable to damage; only by pupating vertically in the long, straight leaf bases of their zingiberalean host plants (Marantaceae and Zingiberaceae) can they protect their proboscis, which can be three times the length of the pupal body. Eurybia larvae and pupae are further protected by an unspecialized association with a variety of ant attendants, which milk them for nectar from dorsal glands. Ant symbioses become more specialized and obligatory in other groups, especially the Nymphidiini. To rear a caterpillar from this group in captivity, it is advisable to keep it with a few ant attendants, or exudates from its nectar-secreting glands will cause it to rot. Ant symbiosis presumably allows butterflies to invade nasty, anty habitats quite lethal to less well-endowed caterpillars (like Heliconius). Calospila cilissa at Corcovado has an obligatory host plant (Stigmaphyllon) that must swarm with an obligatory ant attendant (Crematogaster ). The crowning glory of specialized ant symbiosis is found in species such as Juditha molpe, to whom almost any host plant with extrafloral nectaries will do, so long as it is patrolled by an army of Dolochoderus bispinosus ants. Some ant-attended species even feed on antattended Homoptera, the butterfly equivalent of a wolf in sheep’s clothing. DeVries has shown that specialized organs on these caterpillars are used to manipulate ants by means of sound (via vibratory papillae), and pheromones (via a tentacle organ), as well as by pacifying the ants with nectar. Yet the surface has merely been scratched. Knowledge of ant symbioses has progressed little beyond scanning electron microscopy of the various organs and natural history observations of behaviour. The caterpillars of about a quarter of the Costa Rican genera have never been seen, and the known phylogeny is little more than a polychotomous bush. If you take this book on your next visit to Costa Rica, or indeed anywhere else in the New World tropics, you will be able to leapfrog into a largely unknown world containing some of the most fascinating tropical ecology, in miniature.

James Mallet Galton Laboratory, University College London, 4 Stephenson Way, London, UK NW1 2HE ( [email protected])

References 1 DeVries, P.J (1987) The Butterflies of Costa Rica and their Natural History: Papilionidae, Pieridae, Nymphalidae, Princeton University Press 2 Mallet, J. (1988) Trends Ecol. Evol. 3, 183

Copyright © 1998, Elsevier Science Ltd. All rights reserved. 0169-5347/98/$19.00

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