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Evaluating components of landscape diversity is essential for the implementation of efficient conservation strategies. We evaluated the diversity of Odonata larval assemblages from the Coalcomán mountains (CM), Michoacán, Mexico, and related it to local (site-level) habitat variables. Larvae were collected from shores, riffles and pools in five streams, counted and identified to species, twice per season during 2005. The Shannon Diversity Index (H'), Margalef's Richness Index (R), Simpson's Index as a dominance measure (D) and Pielou's Equitability (J) were used to describe the assemblages, and Renyi's Diversity Profiles were used to order diversity. A Bray-Curtis Similarity Index (BC) was used to evaluate beta diversity. Theoretical richness was estimated using non-parametric and parametric methods. A Canonical Correspondence Analysis (CCA) was applied to explore the relationships of species with site-level environmental variables. A total of 12 245 larvae from 75 species, 28 genera and 8 families were recorded. Over all sites, the dominant species were Erpetogomphus elaps, Macrothemis pseudimitans and Argia pulla. The number of species per locality ranged from 18 to 36, and a high number of species (76%) occurred with relative abundances lower than 1%. A differential distribution of species and abundance in streams, time and strata was observed. Renyi's diversity profiles showed diversity was higher in spring and on shores. Most BC similarity values were smaller than 25%, indicating a high turnover rate in the CM. The high turnover rate reflects a differential distribution of the species along the altitudinal gradient, supporting the hypothesis of Mexico as a betadiverse country. According to the slope of Clench's curve, a reliable list of species was gathered. The CM larval assemblage is currently the largest reported for Mexico, and our results support previous proposals of the CM as a species-rich area for conservation. [ABSTRACT FROM AUTHOR]

The richness, diversity, abundance and indicator species of diversity of adults and larvae of scarab beetles from Santo Domingo Huehuetlán, Puebla, México is analyzed. The field work was done between October 2005 and September 2006, obtaining 1,020 adults specimens of 52 species included in 29 genera from three families of Scarabaeoidea, and 113 edaphicolous larvae belonging to 5 genera, 6 species and 9 morpho-species of Melolonthidae. Species accumulation curves were obtained and the abundance per site, month and capture method was estimated. Comparing the beetle communities of tropical deciduous forest (BTC) and crop lands (ZA), 34 and 36 species and 603 and 417 individuals were found in each site respectively. Shannon's diversity index was 2.79 for ZA and 2.67 for BTC. Likewise, 82 larvae belonging to four genera were found in BTC, and 30 larvae of four genera in ZA. We select adults of 24 indicator species in BTC and 23 species in ZA, all from the subfamilies Dynastinae, Rutelinae and Scarabaeinae. The abundance of indicator species was 313 and 245 and the diversity index was 2.24 and 2.43 in ZA and BTC respectively. We conclude that the species composition of both communities is similar (49%), and the effect of farming near the forest is negligible on the scarab beetle community. [ABSTRACT FROM AUTHOR]

The epipelagic fish known as skipjack (Katsuwonus pelamis) is considered inside the "little tuna" group. The species is distributed in tropical and subtropical waters worldwide. Despite its fisheries importance in Mexico, there is little knowledge about the species in the region. The information from 18 oceanographic cruises inside the Mexican exclusive economic zone in the Gulf of Mexico and Caribbean Sea, was analyzed for the period 1982 to 1992. Plankton was collected in a paired 60 cm mouth bongo net sampler with 0.333 mm mesh nets in oblique tows. The maximum abundance was in spring and summer; 1986 had the largest population (4 881.8544 X 109 larvae) and 1983 the lowest density (566.3748 X 109). The skipjack has suitable conditions for reproduction in this area, and the southwestern region is the most productive. The spawning was greater in the summer. The annual biomass was estimated in 2 513 to 21 659 tons, the high value corresponded to 1986, with potential yields between 7 472 and 10 071 tons. A local fishery seems viable but needs further evidence. [ABSTRACT FROM AUTHOR]

Third instar larvae of Anomala inconstans Burmeister, Ancongnatha sellata Arrow and Ligyrus (Ligyrodes) sallei Bates, are described using 35 specimens collected from soil with corn crops, domestic compost and forest leaf litter and sheep dung in the mountains of northern Chiapas, as well as compost from coffe fruit remains in the mountains of central Veracruz, Mexico. The pupae of A. sellata and L. (L.) sallei also are described using specimens reared in captivity. Drawings of the diagnostic structures, notes on the life cycles, comparative comments on related species, and a key to some common larvae in the soils from Los Altos de Chiapas, Mexico, are included. [ABSTRACT FROM AUTHOR]