Some recent models suggest a new role for evolutionary arms races between males and females in sexual selection. Female resistance to males is proposed to be driven by the direct advantage to the female of avoiding maleimposed reductions in the number of offspring she can produce, rather than by the indirect advantage of selecting among possible sires for her offspring, as in some traditional models of sexual selection by female choice. This article uses the massive but hitherto under-utilized taxonomic literature on genitalic evolution to test, in a twostep process, whether such new models of arms races between males and females have been responsible for rapid divergent evolution of male genitalia. The test revolves around the prediction that ‘new arms races ’ are less likely to occur in species in which females are largely or completely protected from unwanted sexual attentions from males (e.g. species which mate in leks or in male swarms, in which males attract females from a distance, or in which females initiate contact by attracting males from a distance). The multiple possible mechanical functions of male genitalia are summarized, and functions of male genitalic structures in 43 species in 21 families of Diptera are compiled. Functions associated with intromission and insemination (e.g. seizing and positioning the female appropriately, pushing past possible barriers within the female, orienting within the female to achieve sperm transfer), which are unlikely to be involved in new arms races when females are protected, are shown to be common (>50 % of documented cases). This information is then used to generate the new arms race prediction : differences in genitalic form among congeneric species in which females are protected should be less common than differences among congeneric species in which females are vulnerable to harassment by males. This prediction was tested using a sample of 361 genera of insects and spiders. The prediction clearly failed, even when the data were adjusted to take into account several possible biases. Comparative analyses within particular taxonomic groups also failed to show the predicted trends, as did less extensive data on other non-genitalic male display traits. Arms races, as defined in some recent models, seem to have been less important in male–female coevolution of genitalic structures than has been suggested. By elimination, alternative interpretations, such as traditional female choice, which do not predict associations between female protection from harassment and rapid divergent evolution, are strengthened.

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Male-female conflict and genitalia: failure to confirm predictions in insects and spiders.

Considerable nomenclatural revision of the North and Middle American Baetidae has resulted from comprehensive research aimed at formulating a phylogenetic classification. The 17 Nearctic species in Pseudocloeon not previously assigned to Acentrella or Apobaetis are newly placed in Baetis or Barbaetis. Cloeon in the area is restricted to C. cognatum, while two species previously in Cloeon are placed in Centroptilum and nine in Procloeon, a genus considered for the first time in the Nearctic. Definitions of Centroptilum and Procloeon are modified, both now incorporate species with hindwings and species without hindwings, and 19 species are transferred from Centroptilum to Procloeon. Pseudocentroptilum s. auctt. in North America is synonymized with Procloeon. Neocloeon is recognized as a synonym of Centroptilum s. str. and removed from synonymy with Cloeon. Dactylo baetis is placed in synonymy with Camelobaetidius, and all species, including those from South America, are newly combined. Two species of Baetis are transferred to Acerpenna, and two to Fallceon. A checklist includes 154 currently recognized species among 19 genera in the area, and incorporates 21 new species synonyms and 57 new combinations. The names Baetis armillatus and Baetis cinctutus are substituted for Pseudocloeon parvulum and Pseudocloeon cingulatum, repec tively, which otherwise attain homonymie status. Regional distributions for each species and abbreviated synonymies since 1976 are annotated to the checklist. Brief discussions of each genus include information on species diagnosis, revisionary bases, status, and needs. A guide to all nomenclatural changes and added taxa since 1976 provides the bibliographic sources of all such information and serves as a ready index to name equivalencies resulting from extensive recent and present revisions.

Revisionary synopsis of the Baetidae (Ephemeroptera) of North and Middle America.

(As especies de Ephemeroptera (Insecta) registradas para o Brasil). Uma lista da fauna de Ephemeroptera do Brasil, com todas as especies, generos e familias registrados para o pais e apresentada, incluindo os estados para os quais as especies estao reportadas assim como a bibliografia pertinente. Comentarios acerca do estado atual do conhecimento da fauna brasileira tambem sao tecidos. Ate o presente momento 10 familias, 63 generos e 166 especies estao registrados. As familias Baetidae e Leptophlebiidae compreendem mais de 50% de todos os registros, enquanto as regioes Norte e Sudeste sao significativamente melhor estudadas que as demais.

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As espécies de ephemeroptera (insecta) registradas para o Brasil

The Ephemeroptera family Baetidae is one of the most specious families in the Neotropical region and a great effort to improve the taxonomy of this group has been made over the last 10 years in South America. Such studies now enable the development of biomonitoring tools at species-level in the region. A total of 2,199 baetids were collected from seven sampling sites, collected three times (autumn, winter and summer), representing an environmental gradient, draining an area of Atlantic Forest remnants. We describe the mesohabitat of nine Baetidae species and evaluate their responses to environmental degradation and water chemistry by means of biological measures (richness and abundance) and multivariate analysis (Canonical Correspondence Analysis), in order to assess their potential capacity as indicators of these impacts. Most species were found predominantly associated with stony substrates, but some were associated with pool litter, and one species was found predominantly in riffle litter substrate. Species distribution was influenced by the environmental gradient. Based on the CCA ordination, we were able to identify which species were found in pristine versus the most impaired areas, therefore enabling us to establish the sensitivity of each species.

Using Baetidae species as biological indicators of environmental degradation in a Brazilian River Basin

The systematics of the Baetidae has been the subject of much attention during the last three decades, with descriptions of new species and genera as well as several generic revisions. The family now encompasses about 100 genera and 900 species which constitute one-quarter of the world's mayfly diversity. It is thus an opportune time to evaluate the pertinence of these works. The diversity of the Baetidae of the different realms is discussed with emphasis on the rate of endemism and biogeographic affinities. We have also tried to identify the geographical areas where we need more data. The Afrotropics and Neotropics possess the most diversified fauna with the highest degree of endemism. The faunas of the Palaearctic and Nearctic realms are better known but are less diversified especially at a generic level. Oriental and Australasian faunas are still poorly known but are expected to be diversified especially in the tropical regions.

J.R Traver

Papers

A revision of the Baetidae with spatulate-clawed nymphs (Ephemeroptera)