Substantial variation in species ages among vertebrate clades

Ecological and evolutionary studies traditionally assume that species are comparable units of biodiversity. However, not only this assumption is rarely tested, but also there have been few attempts even to assess variation in most emergent, species-level traits and their corresponding underlying mechanisms. One such trait is species age, here defined as the time since the most recent common ancestor between a given species and its sister lineage. In this study, we demonstrate that different terrestrial vertebrate clades vary considerably in the age of their constituent species. In particular, species ages were youngest in mammals and birds as opposed to squamates and amphibians, although considerable variation was found within those clades as well. Sensitivity analyses showed that these results are unaffected by phylogenetic uncertainty or incomplete taxonomic sampling. Interestingly, there was little geographical correspondence in mean species age across taxa, as well as with temperature and precipitation stability over the past 21,000 years. We discuss candidate mechanisms that might explain differences in species ages among clades, and explore the implications of these findings in relation to recent advances in age-dependent speciation and extinction models of diversification

Geographical range overlap networks and the macroecology of species co-occurrence

Direct interactions among species are only possible if there is some overlap in their geographical distributions. However, despite intense focus of macroecological research on species geographical ranges, relatively little theoretical and empirical work has been done on the evolution of range overlap. In this study we explore a simple model of range overlap based on a log-normal distribution of species range sizes along a one-dimensional domain, with or without absorbing boundary conditions. In particular, we focus on the mean and variance of range overlap distributions, as well as the topology of the resulting overlap networks with respect to their degree distribution, evenness, and betweenness scores. According to the model, there is an approximately linear relationship between many aspects of the distribution of range overlaps and their underlying species distributions, such as their mean and variance. However, the expected mean number of non-zero range overlaps for a given species varied from linear to convex depending on the variance of the underlying geographical range distribution. The expected topology of range overlap networks varied substantially depending on the mean and variance in the corresponding geographical distributions, particularly in the case of the degree and closeness distributions. Finally, we test the expectations of our model against five datasets of altitudinal distributions of Neotropical birds. We found strong departures from the expectations based on our model, which could potentially result from phylogenetic niche conservatism related to altitudinal gradients in environmental conditions, or from the asymmetric colonization of mountains by species from lowlands. Potential applications of range overlap networks to a variety of ecological and evolutionary phenomena are discussed

A molecular method for the detection of sally lightfoot crab larvae (Grapsus grapsus, Brachyura, Grapsidae) in plankton samples

The decapod Grapsus grapsus is commonly found on oceanic islands of the Pacific and Atlantic coasts of the Americas. In this study, a simple, quick and reliable method for detecting its larvae in plankton samples is described, which makes it ideal for large-scale studies of larval dispersal patterns in the species

Interações entre formigas e plantas com nectários extraflorais na vegetação do cerrado

Extrafloral nectaries (EFNs) are nectar-secreting glands not directly involved with pollination which may occur on virtually all above-ground plant parts of angiosperms. Recent studies revealed that such glands are widely distributed amongst the woody flora of the Brazilian cerrados. Plants bearing EFNs are visited day and night by a diverse assemblage of nectarivorous ants. In this review we present the data gathered during the past 15 years on the interaction between ants and EFN-bearing plants in cerrado vegetation. Field experiments indicate that ants visiting EFNs may prey or attack insect herbivores on the plant foliage, significantly reducing herbivore damage to leaves, buds or flowers. As a response, some herbivore species have developed an array of mechanisms to circumvent the ants' deterring capacities on their host plants. Ant-derived benefits to plants, however, may vary with the species of visiting ant, with the defensive tactics of the associated herbivores, as well as with the plant species. We discuss the results obtained for different cerrado plant species, and suggest some promising topics for future experimental investigation.Nectários extraflorais (NEFs) são glândulas de néctar não relacionadas com o processo de polinização da planta e que podem ocorrer virtualmente em todas as estruturas vegetativas e reprodutivas de angiospermas. Estudos recentes revelaram que NEFs ocorrem em diversas espécies de arbustos e árvores dos cerrados brasileiros. Plantas portadores destas glândulas são visitadas de dia e de noite por diversas espécies de formigas nectarívoras do cerrado. Nesta revisão apresentamos os dados obtidos nos últimos 15 anos sobre a interação entre formigas e plantas com NEFs em vegetação de cerrado. Estudos experimentais no campo indicam que as formigas visitantes de NEFs podem predar ou injuriar insetos herbívoros que encontram sobre as plantas, reduzindo significativamente as taxas de herbivoria sobre as folhas, botões ou flores. Em resposta, algumas espécies de herbívoros desenvolveram vários mecanismos para evitar o ataque das formigas sobre suas plantas hospedeiras. Os benefícios oferecidos às plantas pelas formigas visitantes, entretanto, podem variar com a agressividade da espécie de formiga, com as estratégias defensivas apresentadas pelos insetos herbívoros, bem como com a espécie de planta. Os resultados obtidos para diferentes espécies de plantas de cerrado são discutidos, indicando áreas promissoras para estudos experimentais futuros.161176Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Formigas cultivadoras de fungos: estado da arte e direcionamento para pesquisas futuras.

A tribo Attini (Hymenoptera: Formicidae) compreende 14 gêneros com aproximadamente 230 espécies de formigas descritas que estão envolvidas em um mutualismo obrigatório com fungos. Este fungo é cultivado no interior das colônias para a alimentação das formigas, e tem como substrato uma variedade de material orgânico. O fungo é utilizado na dieta das formigas, que em retribuição fornecem ao fungo substratos para o crescimento, proteção contra parasitas ou competidores e asseguram a sua reprodução. Embora todas as espécies da tribo cultivem fungo, essas formigas são bastante heterogêneas em relação ao sistema de agricultura, tamanho da colônia e estrutura social, métodos de cultivo do fungo, forrageamento, etc. Nesta revisão são discutidas as principais características da agricultura, simbiose e história natural das formigas cultivadoras de fungos, bem como o direcionamento para as pesquisas futuras com essas formigas.Artigo de revisão

Efficacy of ICON® Maxx in the laboratory and against insecticide-resistant Anopheles gambiae in central Côte d'Ivoire

ABSTRACT: BACKGROUND: Long-lasting treatment kits, designed to transform untreated nets into long-lasting insecticidal nets (LLINs), may facilitate high coverage with LLINs where non-treated nets are in place. In this study, the efficacy of ICON(R) Maxx (Syngenta) was evaluated under laboratory conditions and in an experimental hut trial in central Cote d'Ivoire, where Anopheles gambiae s.s. are resistant to pyrethroid insecticides. METHODS: In the laboratory, polyester and polyethylene net samples were treated with ICON(R) Maxx, washed up to 20 times and their efficacy determined in World Health Organization (WHO) cone assays against a susceptible laboratory An. gambiae s.s. colony. Over a 12-month period, the polyester nets were evaluated in a hut trial to determine mosquito deterrence, induced exophily, blood-feeding inhibition and mortality. RESULTS: In the laboratory, ICON(R) Maxx-treated polyethylene nets showed higher efficacy against pyrethroid-susceptible mosquitoes than polyester nets. After 20 washings, insecticidal efficacy in bioassays was 59.4% knockdown (KD) and 22.3% mortality for polyethylene, and 55.3% KD and 17.9% mortality for polyester nets. In experimental huts, treated nets showed strong deterrence, induced exophily and an over three-fold reduction in blood-fed mosquitoes. More than half (61.8%) of the mosquitoes entering the huts with treated nets were found dead the next morning despite high levels of KD resistance. After washing the treated nets, KD and mortality rates were close to or exceeded predefined WHO thresholds in cone bioassays. CONCLUSION: In contrast to previous laboratory investigation, ICON(R) Maxx-treated nets showed only moderate KD and mortality rates. However, under semi-field conditions, in an area where mosquitoes are resistant to pyrethroids, ICON(R) Maxx showed high deterrence, induced exophily and provided a significant reduction in blood-feeding rates; features that are likely to have a positive impact in reducing malaria transmission. The WHO cone test may not always be a good proxy for predicting product performance under field condition

Outcomes and risk factors associated with endophthalmitis after intravitreal injection of anti-vascular endothelial growth factor agents.

OBJECTIVE: To describe outcomes of and risk factors for endophthalmitis after intravitreal anti-vascular endothelial growth factor (VEGF) injection. DESIGN: Single-center, consecutive, case series and retrospective case-control study. PARTICIPANTS: Between January 1, 2009, and May 31, 2010, 16 vitreoretinal surgeons administered a total of 27 736 injections. During this period, 23 cases of presumed infectious endophthalmitis occurred. Each surgeon used his own preferred injection technique. INTERVENTION: Vitreous or aqueous tap, or both, with intravitreal antibiotic injection and subsequent topical antibiotic and steroid drops. MAIN OUTCOME MEASURES: Visual acuity, bladed lid speculum use, conjunctival displacement, hemisphere of injection, bevacizumab versus ranibizumab, and infectious organism. RESULTS: Seven of 23 cases had positive culture results; 3 grew coagulase-negative Staphylococcus. All cases had pain and vitritis on average 3.4 days (range, 1-6 days) after injection, with no difference between culture-positive and culture-negative groups. Eighteen (78%) of 23 cases had a hypopyon. Fifteen of 23 cases returned to baseline vision (±2 lines) within 3 months. Neither lid speculum use (0.10% vs. 0.066% in the no-use group; P = 0.27), conjunctival displacement (0.11% vs. 0.076% in the no-displacement group; P = 0.43), hemisphere of injection (0.11% superior vs. 0.079% inferior; P = 0.56), or bevacizumab versus ranibizumab (0.11% vs. 0.066%; P = 0.21) affected risk. Analysis of only culture-positive results yielded similar results. There was no statistically significant difference between the proportion of culture-negative cases after bevacizumab injection (83%) versus ranibizumab injection (55%; P = 0.13). CONCLUSIONS: Most patients in whom presumed infectious endophthalmitis develop after anti-VEGF injection regained baseline vision after treatment. Bladed lid speculum use, conjunctival displacement, hemisphere of injection, and type of anti-VEGF agent did not affect risk. No difference in culture-negative endophthalmitis rates was detected after bevacizumab versus ranibizumab injection. Neither the presence of pain, vitritis, decreased vision, hypopyon, nor the interval between injection and development of symptoms differentiate culture-positive from culture-negative cases. Because a subgroup of patients had poor outcomes, a low threshold for vitreous tap with intravitreal antibiotic injection may be warranted. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article

Repurposing Know-how for Drug Development: Case Studies from the Swiss Tropical and Public Health Institute

In pursuing novel therapeutic solutions, drug discovery and development rely on efficiently utilising existing knowledge and resources. Repurposing know-how, a strategy that capitalises on previously acquired information and expertise, has emerged as a powerful approach to accelerate drug discovery and development processes, often at a fraction of the costs of de novo developments. For 80 years, collaborating within a network of partnerships, the Swiss Tropical and Public Health Institute (Swiss TPH) has been working along a value chain from innovation to validation and application to combat poverty-related diseases. This article presents an overview of selected know-how repurposing initiatives conducted at Swiss TPH with a particular emphasis on the exploration of drug development pathways in the context of neglected tropical diseases and other infectious diseases of poverty, such as schistosomiasis, malaria and human African trypanosomiasis