Taxonomic revision and molecular phylogeny of the fig wasp genus AnidarnesBouček, 1993 (Hymenoptera: Sycophaginae)

Besides the pollinators (Agaonidae), several chalcidoid lineages of nonpollinating fig wasps are strictly dependent on Ficus (Moraceae) for reproduction. Overall, nonpollinating fig wasps have not received much consideration. Reliable phylogenetic and taxonomic frameworks are lacking for most groups, which hampers progress in our understanding of the evolution and functioning of fig wasp communities. Here we focus on Anidarnes Bou?ek (Sycophaginae), a member of the Neotropical fig wasp community. We present a detailed morphological analysis as well as the first molecular phylogeny of the genus inferred from two nuclear and two mitochondrial genes (Cytb, COI, EF‐1α and 28S rRNA, 3937 bp). Twelve species are recognised, illustrated and a key to their identification is provided. Of those, only three were previously described and are redescribed here: A. bicolor (Ashmead); A. globiceps (Mayr) and A. brevicauda Bou?ek. In addition, nine new species are described: Anidarnes brevior sp.n . Farache & Rasplus (Costa Rica); A. dissidens sp.n. Farache & Rasplus (Brazil); A. gracilis sp.n. Farache & Rasplus (Costa Rica); A. isophlebiae sp.n. Farache & Rasplus (Costa Rica); A. jimeneziae sp.n. Farache & Rasplus (Costa Rica); A. longiscutellum sp.n. Farache & Rasplus (Brazil); A. martinae sp.n. Farache & Rasplus (U.S.A., Florida); A. nigrus sp.n. Farache & Rasplus (Colombia) and A. rugosus sp.n. Farache & Rasplus (Brazil). Finally, phylogenetic relationships inferred using parsimony, bayesian and maximum likelihood methods are discussed in the light of our morphological observations and the host fig tree taxonomy.     

Genetic variation and phylogenetic relationships of a pantropical species group in Polystachya (Orchidaceae)

Amplified fragment length polymorphism (AFLP) markers were used to investigate the relationships among Polystachya accessions from a group of closely related pantropical tetraploids. Before starting with the fingerprinting analyses, the polyploid accessions were first included in a phylogenetic analysis using low‐copy nuclear DNA data to establish their relationships, which confirmed that they belonged to a species group of closely related allotetraploids. Neo‐ and Palaeotropical polyploid accessions formed two hybrid clades with apparently independent origins. Sampling for the AFLP analyses included single accessions from much of the range of the genus and populations from Costa Rica (CR) and Sri Lanka (SL) to compare population structure and genetic diversity in these two areas in more detail. A splits graph of the complete AFLP data showed three major clusters corresponding to three sources of population sampling (P. concreta, SL; P. foliosa, CR; P. masayensis, CR), with individual accessions from Africa and Indian Ocean islands showing a closer relationship to P. concreta from SL than to the two CR species. Individual accessions from the Neotropics occurred in more isolated positions in the splits network, with little resolution. Some P. foliosa accessions clustered with P. masayensis, suggesting some hybridization between the two species, and this was confirmed by Bayesian structure analysis. However, the splits network, structure and analyses of molecular variance indicated a generally high level of genetic divergence between the two CR species, despite their recent hybrid origin, occurrence in largely the same localities and occasional hybridization. Polystachya foliosa from CR had a higher degree of population‐level genetic structure (Φ_ST = 0.291) than P. masayensis from CR (Φ_ST = 0.161) and P. concreta from SL (Φ_ST = 0.138), possibly because of its occurrence within a larger and more environmentally diverse continuous range than the other two species. Genetic divergence between Neo‐ and Palaeotropical members of the pantropical tetraploid group of Polystachya and the nonmonophyly of P. concreta suggested that P. concreta s.l. should be split and the use of this epithet should be confined to the Neotropics (the type is from Martinique). Other names should be used in Africa and the Asian tropics. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 165 , 235–250.     

Quality calls: phylogeny and biogeography of a new genus of neotropical katydid (Orthoptera: Tettigoniidae) with ultra pure-tone ultrasonics

This paper describes Artiotonus, a new genus of tropical katydid from Colombia and Ecuador. These acoustic ensiferans are represented by three species with a geographic distribution generally restricted to the rainforest of the Bolivar geosyncline of northwestern South America (Pacific). A phylogenetic analysis based on 28 morphological and six behavioural characters produced a tree (A. artius, (A. tinae, A. captivus)) with a consistency index of 0.9. All species are defined by a few autapomorphic changes. The most reliable character for identification is the temporal pattern of the calling song, suggesting a recent genetic divergence. Biogeographic analysis indicates that such genetic divergence began with geographic isolation produced before the Holocene transgression. Species of this genus are remarkable in that the calling song of males exhibits a narrow spectrum with a high quality factor (37–42), unusual values for such ultrasonic signals. A broad discussion on the evolution of tonal calls and pulse trains is offered.     

Seasonal variation in the composition of fish assemblages in small Amazonian forest streams: evidence for predictable changes

1. The effects of seasonal inundation on the biology of fishes on floodplains of large Amazonian rivers are well studied. However, the small seasonal changes in headwater streams are generally considered to have little effect on fish assemblages. 2. In this study, we analysed seasonal changes in the species composition and abundance of fish in small Amazonian forest streams. We sampled fish with hand and seine nets in headwater streams in a 10 000 ha terra‐firme forest reserve near Manaus, Brazil. Each stream was surveyed at the end of the 2005 dry season, at the beginning of the 2006 rainy season and at the beginning of the 2006 dry season, by means of a standardized sampling effort. 3. The numbers of individuals and species caught were higher in the dry season, but rarefaction analyses indicated that greater species numbers could have been due simply to the larger number of individuals caught. 4. Between the dry and rainy season, the direction of changes in species composition in multivariate space varied among sites, especially for quantitative (abundance) data. However, the observed variation among sites was the less than expected if the directions of change were random. 5. Fish assemblages in the second dry season were more similar to those in the previous dry season than expected if changes in species composition among seasons were random. This indicates that a general seasonal pattern in fish assemblages can be detected, despite the existence of some erratic site‐specific changes. 6. Most of the species that showed large seasonal variations in density occupy temporary ponds during the rainy season, when much of the valley is inundated and pond networks form adjacent to streams. Short‐duration lateral migrations to these ponds may play an important role in the seasonal fish‐assemblage dynamics in Amazonian headwater streams. 7. Our results contrast with previous studies on small Amazonian streams, which have found little seasonal change in fish assemblages, and highlight the importance of the abundance of common species as an indicator of general fish assemblage structure in biological monitoring programmes.     

The use of structural reduction in phylogenetic reconstruction of decapods and a phylogenetic hypothesis for 15 genera of Majidae: testing previous larval hypotheses and assumptions

Summary

Using larval data of zoeae from selected genera of majids, we determined tree topologies, levels of homoplasy, and frequencies of reduction under three different assumptions of character argumentation: ordered reduction events, unordered reduction events, and outgroup comparison. Under each assumption we provided a phylogenetic hypothesis for some majid genera and evaluated the assumption that structural reduction can be assumed a priori as a criterion to infer character transformation polarity in phylogenetic reconstruction of decapods. The results indicate that the a priori assumption of “reduction” as the derived condition is not justified because under this assumption, reduction is not always maintained throughout the resulting phylogenetic hypothesis. Furthermore, we also found that this criterion fails to provide the most parsimonious explanation of the data set. Therefore, we reject the use a “reduction=derived” criterion to infer polarity in phylogenetic reconstruction. Phylogenetic analysis using outgroup comparison provided a phylogenetic hypothesis with a better fit and a lower frequency of reduction events. However, we found that statements of homology may be problematic when the number of larval stages in the outgroup differ from those of the ingroup. To overcome this problem, we suggest that, in the absence of evidence for developmental homology, all larval stages should be considered as potential homologues. Using this approach to homology of larval stages, we provide a new phylogenetic hypothesis for 15 genera of majids based on larval morphology. Within Majidae, representative members of Majinae formed a highly nested monophyletic group with the following topology: ((Jacquinotia+Notomithrax) (Leptomithrax+Maja)). In contrast, the Oregoniinae (Hyas+Chionoecetes) formed a basal monophyletic group. Contrary to established ideas for the monophyly of Inachinae, Macrocheira is basal to the Oregoniinae. Other taxa did not form monophyletic groupings based on classical assignment to subfamilies.     

Nematode‐induced galls in Miconia albicans: effect of host plant density and correlations with performance

The study of nematodes parasitizing native plants plays a crucial role in understanding plant–pathogen interactions. In the present study we describe the patterns of attack by an undescribed species of Ditylenchus occurring in Miconia albicans (Melastomataceae), a widespread, native shrub from the Brazilian cerrado. We also tested the hypothesis that nematode‐induced leaf galls negatively correlate to host plant performance and that gall density is a function of host plant density. We collected paired healthy and attacked shoots from 28 individuals of M. albicans and estimated the leaf area lost to nematode‐induced galls in up to 10 leaves per shoot. We analyzed the relationships between leaf area lost to nematode galls and reproductive traits. Nematode attack levels were also compared to the spatial distribution of the host plant. Inflorescence length and fruit production were significantly reduced in attacked shoots compared with healthy shoots. Seeds from attacked shoots showed no significant reduction in germinability or germination time when compared with seeds collected from healthy shoots. Gall density was positively correlated with host density. Despite being seldom studied in tropical ecosystems, nematodes may play an important role in plant fitness and in structuring tropical communities.     

Modelling past and present geographical distribution of the marine gastropod Patella rustica as a tool for exploring responses to environmental change

A climate envelope approach was used to model the distributions of the intertidal gastropod Patella rustica , to test the robustness of forecast responses to climate change. The model incorporated variables that were likely to determine the abundance and the northern range limit of this species in the NE Atlantic. The model was built using classification and regression tree analysis (CART) trained with historical distribution data from the mid 1950s and a set of corresponding climatic and oceanographic variables. Results indicated air and sea temperature, in particular during the reproductive and settlement periods, as the main determinants of the Atlantic distribution of P. rustica . The model was subsequently fed with contemporary climatic data and its output was compared with the current distribution and abundance of P. rustica , assessed during a 2002–2003 survey. The model correctly hindcasted the recent collapse of a distributional gap in northern Portugal, as well as an increase in abundance at locations within its range. The predicted northward expansion of the northern range limit did not occur because the absence of the species was confirmed in a survey encompassing the whole Atlantic French coast up to Brest. Stretches of unsuitable habitat too long to be overcome by dispersal are the likely mechanism controlling the northern limit of the distribution of this intertidal species.