Martina E. Pocco

Patterns of diversification in the high Andean Ponderacris grasshoppers (Orthoptera: Acrididae: Melanoplinae)

The Andes, the worlds longest mountain chain, harbours great taxonomic and ecological diversity. Despite their young age, the tropical Andes are highly diverse due to recent geological uplift. Speciation either followed the orogeny closely or occurred after the Andean uplift, as a result of subsequent climatic changes. Different scenarios have been proposed to explain the diversification of high Andean taxa. The Melanoplinae grasshopper Ponderacris Ronderos & Cigliano is endemic to the eastern slopes of the Andes of Peru and Bolivia, mostly distributed between 1000 and 4000 m above sea level. Diversification in several montane habitats of Bolivia and Peru allows tests via cladistic analysis of distinct possible geographic modes of speciation. Eight species are recognized, with three described here as new with revised diagnostic morphological characters provided: Ponderacris carlcarbonellisp.n.,P. chulumaniensissp.n. and P. amboroensissp.n. Cladistic analyses of 15 species (8 ingroup and 7 outgroup) and 38 morphological characters, under equal and implied weighting, confirm the monophyly of Ponderacris. Characters from the external morphology and colour pattern provided less phylogenetic information than did the male abdominal terminalia and phallic complex. Species distributed in the Peruvian Andes constituted a monophyletic group, whereas those from the Bolivian Andes formed a basal paraphyletic grade. Dispersal–vicariance analysis resulted in one ancestral distribution reconstruction indicating that the most recent common ancestor was distributed in the Lower Montane Yungas of Bolivia. Eleven dispersal and one vicariant events are postulated, with a South‐to‐North speciation pattern coincident with progressive Andean uplift. Vicariance could relate to fragmentation of montane forest during the dry intervals of the late Cenozoic. From the Bolivian area, ancestral Peruvian Ponderacris may have dispersed northward, coinciding with the rise of the Andes. Ten of 11 dispersal events occurred at terminal taxa and are likely to be recent. However, diversification of Ponderacris cannot be explained solely by the South‐to‐North speciation hypothesis, but may also include both vicariance and dispersal across barriers influenced by Pleistocene climatic cycles.

The tracheal mite Locustacarus buchneri in South American native bumble bees (Hymenoptera: Apidae)

As in other regions of the world, bumble bees (Bombus spp.) are important pollinators in the neotropics. Despite its relevance, knowledge on their health is still limited in the region. While external acari are known to occur in these insects, presence of the internal, tracheal mite Locustacarus buchneri is here reported for first time. After the examination of 2,508 individuals of eight Bombus species from Argentina, two workers of Bombus bellicosus and one of Bombus atratus were found parasitized by L. buchneri in localities within San Luis and Buenos Aires provinces, respectively. The rare occurrence recorded agrees with findings from elsewhere in the world.

Grasshoppers of the Andes: new Melanoplinae and Gomphocerinae taxa (Insecta, Orthoptera, Acrididae) from Huascarán National Park and Callejón de Huaylas, Ancash, Peru

ABSTRACT The grasshopper fauna from Huascarán National Park and the valleys of “Callejón de Conchucos” and “Callejón de Huaylas”, Perú, has been sampled during two surveys of the area in 2004 and 2008. In this paper, two new genera (Tiyantiyana n. gen. and Huaylasacris n. gen.) and six new species collected during the surveys are described: Tiyantiyana sunipenis n. gen, n. sp., Huaylasacris maxicerci n. gen, n. sp., Maeacris chilikuti n. sp., M. saytu n. sp., M. ayasqa n. sp. of the subfamily Melanoplinae and Orphulella chumpi n. sp. of the subfamily Gomphocerinae. Previous records on the highland grasshoppers of the Peruvian Andes were almost nonexistent. The new acridids described here were collected at the high-altitude puna grassland, between 3182 and 4660 m a.s.l. Puna is one of the most heavily modified natural regions of Peru. Since grasshoppers are a useful group for bioindication, it is important to acquire knowledge on their diversity in such environmental conditions. This paper includes many embedded links to images of type specimens, maps based on geo-referenced specimen data, and keys to species, all available at Orthoptera Species File Online (http://orthoptera.speciesfile.org).

The fate of endemic insects of the Andean region under the effect of global warming

Three independent but complementary lines of research have provided evidence for the recognition of refugia: paleontology, phylogeography and species distributional modelling (SDM). SDM assesses the ecological requirements of a species based on its known occurrences and enables its distribution to be projected on past climatological reconstructions. One advantage over the other two approaches is that it provides an explicit link to environment and geography, thereby enabling the analysis of a large number of taxa in the search for more general refugia patterns. We propose a methodology for using SDM to recognize biogeographical patterns of endemic insects from Southern South America. We built species distributional models for 59 insect species using Maxent. The species analyzed in the study have narrow niche breadth and were classified into four assemblages according to the ecoregion they inhabit. Models were built for the Late Pleistocene, Mid-Holocene and Present. Through the procedure developed for this study we used the models to recognize: Late Pleistocene refugia; areas with high species richness during all three periods; climatically constant areas (in situ refugia); consistent patterns among in situ refugia, Pleistocene refugia and current distribution of endemic species. We recognized two adjacent Pleistocene refugia with distinct climates; four in situ refugia, some of which are undergoing a process of fragmentation and retraction or enlargement. Interestingly, we found a congruent pattern among in situ refugia, Pleistocene refugia and endemic species. Our results seem to be consistent with the idea that long-term climate stability is known to have a key role in promoting persistence of biodiversity in an area. Our Pleistocene and in situ refugia are consistent with refugia identified in studies focusing on different taxa and applying other methodologies, showing that the method developed can be used to identify such areas and prove their importance for conservation.

Taxonomic delimitation in color polymorphic species of the South American grasshopper genus Diponthus Stål (Orthoptera, Romaleidae, Romaleini)

The South American genus Diponthus Stal comprises species with cryptic and probably aposematic colorations. It belongs to a group of grasshoppers, tribe Romaleini, where color polymorphism is common. Morphometric techniques were used to clarify the taxonomic limits and status of six nominal species of Diponthus: D. permistus (Serville), D. argentinus Pictet & Saussure, D. pycnostictus Pictet & Saussure, D. communis Bruner, D. pictus (Bolivar) and D. schulzi Bruner. Results of cluster (CA) and principal component (PCA) analyses showed that D. pycnostictus can be defined by a unique combination of characters, while the remaining nominal species represent different color morphs of a single taxon, here recognized as D. argentinus. We also used statistical analyses to examine whether the discontinuities in body coloration of the polymorphic D. argentinus could be explained by geographic variation. The distribution patterns of body coloration of D. argentinus do not appear to be restricted to any particular biogeographic region and no character correlation resulted with latitude. Furthermore, the results show that color morphs display high levels of overlap across the geographic range, as well as intra-population variation. We conclude that in D. argentinus body coloration varies considerably across the geographic distribution range but without any noticeable color gradient correlated with the latitude. According to the phylogenetic species concept (PSC) we consider D. pycnostictus Pictet & Saussure and D. argentinus Pictet & Saussure as valid species. The following synonymies are proposed under D. argentinus: D. communis Bruner n. syn., D. schulzi Bruner n. syn., D. pictus (Bolivar) n. syn., and D. permistus (Serville) n. syn. We declare D. permistus (Serville) a nomen oblitum.

Diversification patterns of the grasshopper genus Zoniopoda Stål (Romaleidae, Acridoidea, Orthoptera) in open vegetation biomes of South America

The open vegetation biomes, within the limits of the Chacoan subregion, occur along a diagonal in eastern South America covering a large range of environmental conditions. In order to contribute to the knowledge on the biodiversity of these open biomes, we analysed the phylogenetic relationships of the grasshopper genus Zoniopoda to the remaining South American Romaleinae, and examined the biogeographical patterns of diversification of the genus. The study is based on morphological and molecular (COI and H3) evidence, including 12 species of Zoniopoda and 17 species of four tribes of South American Romaleinae. We describe a new species of Zoniopoda, and test its taxonomic placement within the group. Results of our phylogenetic analyses recovered Zoniopoda as a monophyletic group with high support values. According to the dispersion–vicariance analysis, the ancestor of Zoniopoda may have been distributed in an area corresponding to the Chacoan and Cerrado provinces. A vicariant event, that could be explained by the uplift of the Brazilian Plateau and the subsidence of the Chaco, is hypothesized to have occurred splitting the ancestral distribution of Zoniopoda, resulting in the independent evolution of the Tarsata group within the Cerrado and the Iheringi group in the Chacoan subregion.