Keith S. Brown

Diversity, disturbance, and sustainable use of Neotropical forests: insects as indicators for conservation monitoring

Sustainable use of tropical forest systems requires continuous monitoring of biological diversity and ecosystem functions. This can be efficiently done with ‘early warning‘ (short-cycle) indicator groups of non-economical insects, whose population levels and resources are readily measured. Twenty-one groups of insects are evaluated as focal indicator taxa for rapid assessment of changes in Neotropical forest systems. Composite environmental indices for heterogeneity, richness, and natural disturbance are correlated positively with butterfly diversity in 56 Neotropical sites studied over many years. Various components of alpha, beta and gamma-diversity show typical responses to increased disturbance and different land-use regimes. Diversity often increases with disturbance near or below natural levels, but some sensitive species and genes are eliminated at very low levels of interference. Agricultural and silvicultural mosaics with over 30% conversion, including selective logging of three or more large trees per hectare, show shifts in species composition with irreversible loss of many components of the butterfly community, indicating non-sustainable land and resource use and reduction of future options. Monitoring of several insect indicator groups by local residents in a species-rich Brazilian Amazon extractive reserve has helped suggest guidelines for cologically, economically, and socially sustainable zoning and use regimes.

Phylogeny of the Nymphalidae (Lepidoptera).

A generic-level phylogeny for the butterfly family Nymphalidae was produced by cladistic analysis of 234 characters from all life stages. The 95 species in the matrix (selected from the 213 studied) represent all important recognized lineages within this family. The analysis showed the taxa grouping into six main lineages. The basal branch is the Libytheinae, with the Danainae and Ithomiinae on the next branch. The remaining lineages are grouped into two main branches: the Heliconiinae-Nymphalinae, primarily flower-visitors (but including the fruit-attracted Coeini); and the Limenitidinae (sensu strictu), Biblidinae, and the satyroid lineage (Apaturinae, Charaxinae, Biinae, Calinaginae, Morphinae, Brassolinae, and Satyrinae), primarily fruit-attracted. Data partitions showed that the two data sets (immatures and adults) are very different, and a partitioned Bremer support analysis showed that the adult characters are the main source of conflict in the nodes of the combined analysis tree. This phylogeny includes the widest taxon coverage of any morphological study on Nymphalid butterflies to date, and supports the monophyly and relationships of most presently recognized subgroups, providing strong evidence for the presently accepted phylogenetic scheme.

As borboletas (Lepidoptera, Papilionoidea) do Distrito Federal, Brasil

The butterflies (Lepidoptera, Papilionoidea) of the Distrito Federal, Brazil. An updated list containing 504 species and 506 subspecies of butterflies (Papilionoidea) found in the Distrito Federal (central Brazil) in the last four decades is presented in this study, including data obtained in the literature, our personal collections, and several entomological collections recently visited, but not species with presumed distribution in the region. Some aspects concerning the occurrence of threatened species and the conservation of the butterfly fauna in the Distrito Federal are also discussed.

Predation on Aposematic Ithomiine Butterflies by Tanagers (Pipraeidea melanonota)

Tanagers (Pipraeidea melanonota) have been found preying heavily and selectively on winter concentrations of 22 species of ithomiine butterflies in the region of Sumare, Sao Paulo. Flying birds catch resting butterflies in the cold of the early morning, take them to favored perches, and squeeze out and eat the abdominal contents, leaving the remainder of the butterfly as testimony to the predation. No other insectivorous birds in the region have been observed to attack these butterflies, nor are any literature reports known for such predation on ithomiines, which are well-known aposematic models for mimicry rings throughout the Neotropics. The commonest ithomiine species in the colonies, Mechanitis polymnia, is attacked in far greater proportion than its true abundance, probably because of its conspicuous coloration and roosting habits, and its more sluggish behavior than the other two common larger species, which are taken in proportions lower than expected from analysis of net captures. This behavior pattern is probably a function of abundance in the butterflies, thereby leading to the density-dependent predation observed in the system. NEOTROPICAL BUTTERFLIES in the nymphalid subfamily Ithomiinae are regarded as classical unpalatable models for Miillerian and Batesian mimicry rings (Bates 1862, Muller 1878), to the point of serving as prime movers for the evolution of these groups of look-alikes (Kaye 1907, Brown and Benson 1974). To our knowledge, they have never been reported to have been eaten by vertebrate predators.

Qualitative patterns of pyrrolizidine alkaloids in ithomiinae butterflies

Abstract Pynolizidine alkaloids (PAs) were analysed in 40 species (38 genera, all 14 tribes) of the butterfly subfamily Ithomiinae. The principal PAs found were the epimers lycopsamine and intermedine. These results suggest that ithomiines visit mainly PA sources containing moncester lycopsamine-type PAs, and transform various other diastereoisomers into lycopsamine and intermedine, with the 7 R configuration. Other PA-types found in butterflies are probably related to the availability of PA sources. Unknown PAs ([M] + 297), that resemble the arctiid insect-PA callimorphine, were found in small amounts in 10 species.

Guia das borboletas frugívoras da Reserva Estadual do Morro Grande e região de Caucaia do Alto, Cotia (São Paulo)

As especies de borboletas frugivoras (Lepidoptera: Nymphalidae) conhecidas da Reserva Estadual do Morro Grande (Cotia, SP) e Caucaia do Alto sao apresentadas na forma de um guia de campo.

Variation of pyrrolizidine alkaloids in Ithomiinae: A comparative study between species feeding on Apocynaceae and Solanaceae

SummaryThe primitive, Apocynaceae-feeding Ithomiine,Tithorea harmonia, incorporates dehydropyrrolizidine alkaloids (PAs) from its larval foodplant (Prestonia acutifolia), rarely visiting PA sources pharmacophagously in the adult; females show higher concentrations of PAs than males, with similar variance. The close relativeAeria olena (feeding onP. coalita, without PAs) shows similar PA concentrations in both sexes and greater variation in males, like more advanced Solanaceae-feeding Ithomiine such asMechanitis polymnia, which likeA. olena obtain PAs by pharmacophagy in the adult (mainly males). This difference is due to the dynamics of PA incorporation in these species. Little variation in PA content was found among allopatric populations of the same species, but variation in available PA sources in different months was correlated with different average storage levels in the butterflies.

Resources and conservation of neotropical butterflies in urban forest fragments

Abstract Three remnants of native semideciduous forest in southeastern Brazil within the urban area of Campinas (100 km north of Sao Paulo, nearly 900 000 inhabitants) were censused weekly for butterflies and their adult and larval food-plants. Seventy-eight species were recorded in the larger (12 ha) peripheral area while 47 and 46 species were found in two small (1–2 ha) woods in the residential zone of the city. At least 16 species reproduce in the small woods, which may aid the survival of some scarce butterfly species in the urban area. Limitation of adult food resources in the woods had a great influence on populations of two different butterfly guilds (nectar- and fruit/sap-eating species).

Geographical patterns of evolution in Neotropical Lepidoptera: differentiation of the species of Melinaea and Mechanitis (Nymphalidae, Ithomiinae)*

Abstract Biosystematic analysis incorporating abundant new field data from many parts of the Neotropics has led to an ordered revision of the mimetic ithomiine genera Melinaea and Mechanitis. The various polytypic species of these general probably served as prime movers for the differentiation of other mimetic butterflies in Quaternary forest refuges. The revisions are presented in the form of supplements to the works of Richard M. Fox on these genera, with analyses based on his divisions. Seven species (or monophyletic species‐groups) and sixty‐three well‐differentiated geographic subspecies (six of these described here for the first time) are recognized in Melinaea. Specimens are illustrated which demonstrate intergradation between refuge‐derived subspecies. Five species and fifty‐two differentiated subspecies are recognized in Mechanitis, whose members are more abundant and gregarious, more plastic, and apparently more vagile than those of Melinaea, resulting in fewer clear‐cut mimetic associations, more extensive blurring of differentiation patterns, and apparently fewer incipient biological species in this genus than in Melinaea.

Evolutionary strategies of chemical defense in aposematic butterflies: Cyanogenesis in Asteraceae-feeding American Acraeinae

SummaryAmerican Acraeinae butterflies often ingest large amounts of dehydropyrrolizidine alkaloids (PAs) from their Asteraceae hostplants in both larval and adult stages, but do not normally store these compounds for defence, instead biosynthesizing large amounts of the cyanogenic glucoside linamarin in all stages. This defence syndrome (rejection of plant toxins andde novo synthesis of protective chemicals) is considered to be the most evolved among aposematic (unpalatable mimicry-model) butterflies, as are the Acraeinae and Heliconiini which also synthesize cyanogens. Storage or minimal processing of larval hostplant-derived defensive chemicals is widespread and characterizes the most primitive model groups; an intermediate series (Danainae/Ithomiinae) also obtains the principal defensive chemicals (PAs) from plants, but mostly in the adult stage. These syndromes are discussed and contrasted with the pattern seen in Chrysomelidae beetles, wherede novo synthesis is widespread and considered primitive.