Correlations between environmental parameters and the distribution of four chromosomal taxa in the acridine grasshopperCaledia captiva (F.) have been analyzed. A bioclimate prediction system (BIOCLIM) was used as a model to determine their bioclimatic envelopes and to predict their probable geographic distributions, based on climatic similarities with actual distributions. New, and formerly unsuspected, distribution areas are predicted. Parapatric boundaries are defined that actually coincide with known limits. The general distribution of the four taxa is correlated with rainfall seasonality and a temperature gradient. Their distributional boundaries are mostly in accordance with extreme values in rainfall in an east-west direction and temperature in a north-south direction. A nonmetric multidimensional scaling analysis of one selected narrow parapatric boundary confirms the nature of the geographic correlation with several climatic extreme values. The climatic and vegetation analyses suggest that sharp parapatric distributions can be maintained by gradual environmental influences and that coincidence with abrupt ecotones is not necessary. At least one of the parapatric boundaries seems to be relatively recent in origin (2000-6000 years) and on the basis of the location of extreme climatic values as well as chromosomal and genetic markers it is expected to slowly move further south and east of its present location apparently following a climatically established boundary.

This paper is an analysis of the distribution of areas of high species richness and endemicity based on dung beetles living in the different Holdridge life-zones of Costa Rica by using a geographic information system (GIS). Endemism was examined in relation to whether the species were shared with Nicaragua and/or Panama, or if they were strictly Costa Rican. The species composition of dung beetle distributions in the sampling areas and life-zones was evaluated. Species distribution was also analyzed in relation to altitudinal levels. The species richness and endemicity maps served as a base for doing a gap analysis and defining four different levels of high priority conservation areas. We also investigated what percentage of these priority areas is under some type of protection or conservation scheme and which of these areas should be enlarged. Also considered is the feasibility that these areas under protection have for enlargement, considering possible problems and interactions with present land-use. We include a list of all the recorded dung beetle species for Costa Rica, as well as their presence in the different Holdridge life-zones and their endemicity status. This study clearly demonstrates the need to include insects in biodiversity-endemicity studies because different and more detailed results are obtained in relation to vertebrate and plant-based studies.

Freshwater biodiversity is declining dramatically, and the current biodiversity crisis requires defining bold goals and mobilizing substantial resources to meet the challenges. While the reasons are varied, both research and conservation of freshwater biodiversity lag far behind efforts in the terrestrial and marine realms. We identify fifteen pressing global needs to support informed global freshwater biodiversity stewardship. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated action towards its sustainable management and conservation.

An analysis of vicariant speciation of Geotrupes and Phanaeus (Coleoptera, Geotrupidae, Scarabaeidae) from the mountains of Oaxaca, Mexico is undertaken. The new species of dung beetle (Coleoptera: Scarabaeidae) from Oaxaca, Mexico, Phanaeus dionysius sp. n. is described. Photos of the habitus and a distribution map are provided. Phanaeus malyi Arnaud is revalidated. An updated key for the Phanaeus endymion species group and new localities are also presented. An updated key for the Geotrupes of Oaxaca and new locality records are also submitted.

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation.

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Independent molecular, biochemical, and cytological markers have been used to assess the evolutionary status of a narrow hybrid zone between two genomically distinct taxa of the grasshopper Caledia captiva. Despite the extreme narrowness (<1 km) of the hybrid zone when assessed in terms of its chromosomal profile, other diagnostic nuclear and cytoplasmic markers are found at high frequencies in populations up to 400 km beyond the chromosomal limits of the zone. These data suggest that the hybrid zone is very old and capable of moving while still retaining its narrow chromosomal profile. The data also suggest that the chromosomal rearrangements are the principal components maintaining this narrow hybrid zone and that strong selective forces, acting upon the structure of the genome, are involved. Analysis of chromosomal variation has revealed that the Moreton taxon has a complex chromosomal cline in which every chromosome changes from metacentric to acrocentric or telocentric along the cline. We argue that the chromosomal rearrangements which are involved in maintaining the narrow hybrid zone are themselves playing an adaptive role within the population, both as homo- and hetero-zygotes. A model is presented to explain these patterns of genomic change along environmental gradients as an adaptation, probably at the cellular level, to establish a temporal synchrony of events during embryogenesis.