In the lowland deciduous and riparian evergreen forests of Guanacaste Province, Costa Rica, the insect seed predators are highly host-specific and display a variety of traits suggesting that the ways they use hosts are not randomly distributed. The vertebrate seed predators may feed on many species of seeds over the course of a year or within the animal population, but, at any one time or with any one individual, strong facultative host-specificity occurs. Furthermore, the vertebrates have a variety of species-specific behaviors that suggest specialization to overcome the defenses of particular seed species. Even the dispersal agents kill seeds as they pass through their guts, and the details of seed-defecation patterns should be important to the seed. Within this forest, leaf-eating caterpillars seem to be either specialized on one or a few species of plants, or spread over many. While an entire forest is never defoliated at one time, defoliations and severe herbivory occur with many plant species in various seasons or years. Herbivory by large herbivores is probably trivial when compared to that of the insects. Furthermore, the defenses that the large herbivores have to overcome may well have been selected for by both insects and extinct Pleistocene large herbivores. I suspect that many of the animal-plant interactions in this forest are not coevolved, and those that are coevolved will be difficult to distinguish from those that are not. THERE ARE TWO QUITE DIFFERENT KINDS of patterns of herbivory.' First there is the way an individual herbivore bites a plant and the influence of this on other herbivores (Janzen 1973) and on the fitness, health, and growth patterns, et cetera of the bitten plant (e.g., Simberloff et al. 1978; Oppenheimer and Lang 1969; McKey 1978; Chester 1950; Janzen 1976a, b; Rockwood 1973). Much more research is needed on the allocation responses, economics of retention versus shedding of damaged parts, and strategic damage versus absolute damage. For example, the production of induced chemical defenses may raise the fitness of a plant not through the lowering of the absolute amount of herbivore damage done, but rather by causing the damage to be distributed in a manner that harms the plant less (Janzen 1979). However, this essay is not directed at this pattern of herbivory, but rather at the second one. This is the distribution of the species and quantities of herbivores across the mosaic of plant species, developmental stages, plant parts, habitats, defense types, and time. I focus on this pattern of herbivory in the deciduous forests, and their contained riparian vegetation and old pastures, in Santa Rosa National Park (SRNP), northwestern Guanacaste Province, Costa Rica (0-300 m elevation). INSECT SEED PREDATORS The lowlands of Guanacaste Province exclusive of the Nicoya Peninsula (about 3200 kiM2) have about 975 species of broad-leafed plants at latest count (Janzen and Liesner 1980). In an ongoing study of the insects that eat the seeds of these plants, at least 110 species of beetles (Bruchidae, Curculionidae, Cerambycidae) were reared from more than 3700 samples of fruits and seeds (Janzen 1980a). The seeds of at least 100 of the 975 species of plants were regularly found to have beetle larvae seed predators that develop in the seeds at the stage between nearly full-sized and mature (preand post-dispersal). Most of the species of beetles were specific to a particular plant species: 83 species (75%) preyed on one plant species, each of 14 preyed on only two, nine on three, and two on four. The bruchid Stator pruininus preyed on six species and Stator limbatus on eight species, and there was no overlap in their two prey lists (although all prey were legumes). Of the 100 prey species, 63 were in the Leguminosae, and the remainder were spread among 17 other plant families; however, only 17 percent of the broadleafed plant species in the Guanacaste lowlands are

Patterns of herbivory in a tropical deciduous forest

Background: The 1400 species of hawkmoths (Lepidoptera: Sphingidae) comprise one of most conspicuous and wellstudied groups of insects, and provide model systems for diverse biological disciplines. However, a robust phylogenetic framework for the family is currently lacking. Morphology is unable to confidently determine relationships among most groups. As a major step toward understanding relationships of this model group, we have undertaken the first large-scale molecular phylogenetic analysis of hawkmoths representing all subfamilies, tribes and subtribes. Methodology/Principal Findings: The data set consisted of 131 sphingid species and 6793 bp of sequence from five protein-coding nuclear genes. Maximum likelihood and parsimony analyses provided strong support for more than twothirds of all nodes, including strong signal for or against nearly all of the fifteen current subfamily, tribal and sub-tribal groupings. Monophyly was strongly supported for some of these, including Macroglossinae, Sphinginae, Acherontiini, Ambulycini, Philampelini, Choerocampina, and Hemarina. Other groupings proved para- or polyphyletic, and will need significant redefinition; these include Smerinthinae, Smerinthini, Sphingini, Sphingulini, Dilophonotini, Dilophonotina, Macroglossini, and Macroglossina. The basal divergence, strongly supported, is between Macroglossinae and Smerinthinae+Sphinginae. All genes contribute significantly to the signal from the combined data set, and there is little conflict between genes. Ancestral state reconstruction reveals multiple separate origins of New World and Old World radiations. Conclusions/Significance: Our study provides the first comprehensive phylogeny of one of the most conspicuous and wellstudied insects. The molecular phylogeny challenges current concepts of Sphingidae based on morphology, and provides a foundation for a new classification. While there are multiple independent origins of New World and Old World radiations, we conclude that broad-scale geographic distribution in hawkmoths is more phylogenetically conserved than previously postulated.

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Phylogeny and Biogeography of Hawkmoths (Lepidoptera: Sphingidae): Evidence from Five Nuclear Genes

Background: When a specimen belongs to a species not yet represented in DNA barcode reference libraries there is disagreement over the effectiveness of using sequence comparisons to assign the query accurately to a higher taxon. Library completeness and the assignment criteria used have been proposed as critical factors affecting the accuracy of such assignments but have not been thoroughly investigated. We explored the accuracy of assignments to genus, tribe and subfamily in the Sphingidae, using the almost complete global DNA barcode reference library (1095 species) available for this family. Costa Rican sphingids (118 species), a well-documented, diverse subset of the family, with each of the tribes and subfamilies represented were used as queries. We simulated libraries with different levels of completeness (10-100% of the available species), and recorded assignments (positive or ambiguous) and their accuracy (true or false) under six criteria. Results: A liberal tree-based criterion assigned 83% of queries accurately to genus, 74% to tribe and 90% to subfamily, compared to a strict tree-based criterion, which assigned 75% of queries accurately to genus, 66% to tribe and 84% to subfamily, with a library containing 100% of available species (but excluding the species of the query). The greater number of true positives delivered by more relaxed criteria was negatively balanced by the occurrence of more false positives. This effect was most sharply observed with libraries of the lowest completeness where, for example at the genus level, 32% of assignments were false positives with the liberal criterion versus < 1% when using the strict. We observed little difference (< 8% using the liberal criterion) however, in the overall accuracy of the assignments between the lowest and highest levels of library completeness at the tribe and subfamily level. Conclusions: Our results suggest that when using a strict tree-based criterion for higher taxon assignment with DNA barcodes, the likelihood of assigning a query a genus name incorrectly is very low, if a genus name is provided it has a high likelihood of being accurate, and if no genus match is available the query can nevertheless be assigned to a subfamily with high accuracy regardless of library completeness. DNA barcoding often correctly assigned sphingid moths to higher taxa when species matches were unavailable, suggesting that barcode reference libraries can be useful for higher taxon assignments long before they achieve complete species coverage.

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When species matches are unavailable are DNA barcodes correctly assigned to higher taxa? An assessment using sphingid moths

The foliage of 80 species common in the Santa Rosa National Park, Costa Rica, has been analysed for content of total phenolics, condensed tannins, acid detergent fibre and water. Wherever possible analyses were performed at three stages in the life cycle of the leaf: young but fully expanded (coinciding with the beginning of the rainy season); middle-aged (two months later); and old (six months later). A comparison of the three age classes showed no significant change in the levels of phenolics or fibre as leaves aged but water content decreased significantly. A comparison of deciduous and evergreen species in the sample showed that the latter group had leaves with a significantly higher fibre content at all three sampling times, most particularly at the beginning of the rainy season, but other measures were not significantly different. Alkaloids were much more common in the foliage of deciduous species and it was observed that their distribution differed significantly from that of total phenolics and condensed tannins. It is suggested that the interaction that occurs between many tannins and alkaloids would be liable to reduce the defence capability of both classes of compounds if they occurred together.



High levels of defoliation occur in the early rainy season (third to tenth weeks) due to larvae of moths of the Sphingidae and Saturniidae. A comparison of investigated tree species that host larvae of these two taxa shows a striking dichotomy. Species that are selected by Sphingidae tend to be relatively deficient in levels of phenolics but are more likely to contain alkaloids, and probably other small toxic molecules. Saturniidae, on the other hand, appear to prefer host-species rich in phenolics but poor in alkaloids.

A seasonal census of phenolics, fibre and alkaloids in foliage of forest trees in Costa Rica: some factors influencing their distribution and relation to host selection by Sphingidae and Saturniidae

In the heavily managed boreal forest of Scandinavia, ants, especially large colonies of red forest ants (Formica spp.), are abundant and brown bears (Ursus arctos) intensively feed on them. In contrast, the beech (Fagus sylvatica) forests of Slovenia provide only suboptimal habitat for ants and large ant colonies are virtually absent. To quantify how much ant use by brown bears is a matter of availability or preference, we quantified ant availability, species composition, and ant use. The estimated biomass of ants available to brown bears was very low in Slovenia compared with those in Sweden, averaging 135 vs. 9600 g/ha, respectively. Nevertheless, the frequency of occurrence of ants in Slovenian brown bear scats was high, averaging 85% and accounting for 25% of the ingested dry mass during the summer, which was nearly as much as their frequency of occurrence in Swedish brown bear scats during the summer. Although brown bears in Slovenia had year-round access to artificial feeding sites and the availabil...

P. Harris

Papers

Food-plant groups of the semanophorinae (lepidoptera: sphingidae): a possible taxonomic tool