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San Pedro de Atacama, Chile

Rivera-Hutinel A.,Institute Entomologia | Bustamante R.O.,University of Chile | Marin V.H.,University of Chile | Medel R.,University of Chile

Plant-animal interaction networks provide important information on community organization. One of the most critical assumptions of network analysis is that the observed interaction patterns constitute an adequate sample of the set of interactions present in plant-animal communities. In spite of its importance, few studies have evaluated this assumption, and in consequence, there is no consensus on the sensitivity of network metrics to sampling methodological shortcomings. In this study we examined how variation in sampling completeness influences the estimation of six network metrics frequently used in the literature (connectance, nestedness, modularity, robustness to species loss, path length, and centralization). We analyzed data of 186 flowering plants and 336 pollinator species in 10 networks from a forest-fragmented system in central Chile. Using species-based accumulation curves, we estimated the deviation of network metrics in undersampled communities with respect to exhaustively sampled communities and the effect of network size and sampling evenness on network metrics. Our results indicate that: (1) most metrics were affected by sampling completeness but differed in their sensitivity to sampling effort; (2) nestedness, modularity, and robustness to species loss were less influenced by insufficient sampling than connectance, path length, and centralization; (3) robustness was mildly influenced by sampling evenness. These results caution studies that summarize information from databases with high, or unknown, heterogeneity in sampling effort per species and should stimulate researchers to report sampling intensity to standardize its effects in the search for broad patterns in plant- pollinator networks. © 2012 by the Ecological Society of America. Source

Socias M.G.,Institute Tecnologia Agroindustrial del Noroeste Argentino ITANOA | Socias M.G.,CONICET | Van Nieuwenhove G.,Institute Entomologia | Murua M.G.,Institute Tecnologia Agroindustrial del Noroeste Argentino ITANOA | And 4 more authors.
Journal of Economic Entomology

The soybean stalk weevil, Sternechus subsignatus Boheman 1836 (Coleoptera: Curculionidae), is a very serious soybean pest in the Neotropical region. Both adults and larvae feed on soybean, causing significant yield losses. Adult survival was evaluated during three soybean growing seasons under controlled environmental conditions. A survival analysis was performed using a parametric survival fit approach in order to generate survival curves and obtain information that could help optimize integrated management strategies for this weevil pest. Sex of the weevils, crop season, fortnight in which weevils emerged, and their interaction were studied regarding their effect on adult survival. The results showed that females lived longer than males, but both genders were actually long-lived, reaching 224 and 176 d, respectively. Mean lifetime (l50) was 121.88 ± 4.56 d for females and 89.58 ± 2.72 d for males. Although variations were observed in adult longevities among emergence fortnights and soybean seasons, only in December and January fortnights of the 2007-2008 season and December fortnights of 2009-2010 did the statistically longest and shortest longevities occur, respectively. Survivorship data (lx) of adult females and males were fitted to the Weibull frequency distribution model. The survival curve was type I for both sexes, which indicated that mortality corresponded mostly to old individuals. © 2015 The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. Source

Oophagous biological control agents of T. absoluta naturally present in crops in South America (Buenos Aires and Tucumán Provinces, Argentina) and Europe (Lazio, Italia) were surveyed. A taxonomic list of species and the natural mortality rates caused by parasitism and predation are reported. Furthermore, the first record of Encarsia porteri (Mercet) (Hymenoptera: Aphelinidae) parasitizing T. absoluta eggs is informed. © 2015, Universidad Nacional de Cuyo. All rights reserved. Source

The augmentative biological control of Diatraea saccharlis Fabricius (Lepidoptera: Crambidae) requires the mass rearing of the parasitoid Cotesia flavipes Cameron (Braconidae: Microgastrinae), and for this, it's necessary the development of efficient artificial diets. The goal was to examine the effects of different diet types on biological parameters of D. saccharalis and their impact on coccon production of C. flavipes. 46136 eggs of D. saccharalis were sow on eleven combinations of artificial diets, with two types of flours and three types of antibiotics. The results showed that the diet composition affected biological parameters of both species. The larger efficiency in the rearing was obtained with the use of combinations of bean flour and ampicillin. However, if we consider the relationship between production costs and biological parameters, the diet with bean flour, oxytetracycline and streptomycin was the most adequate for mass rearing. © 2014, Universidad Nacional de Cuyo. All rights reserved. Source

Tauber C.A.,Cornell University | Tauber C.A.,University of California at Davis | Mantoanelli E.,State University of Norte Fluminense | Albuquerque G.S.,State University of Norte Fluminense | And 4 more authors.

Leucochrysa (Leucochrysa) loretana Navás, 1935, a species described from Argentina, was discovered to have a geographically variable polymorphism, with two forms of adult coloration. One of the morphs (the "brown- spotted" morph) is indistiguishable from the widespread species Leucochrysa (Leucochrysa) longicornis (G. Gray in Cuvier, 1832) and the second morph (the "white-spotted" morph) is identical to another Argentinian species, Leucochrysa (Leucochrysa) boxi Navás, 1930. These observations generated a number of nomenclatural changes: (1) The oldest of the three names, L. (L.) longicornis (= Hemerobius longicornis), is a secondary homonym of a Linnaean species described in 1764 and therefore is unavailable for Gray's species. (2) Thus, by priority, L. (L.) boxi becomes the valid name for the polymorphic species. (3) Leucochrysa (L.) loretana becomes a synonym of L. (L.) boxi. (4) The above three names are stabilized by the designation of primary types for each of the species, and by other nomenclatural actions. Specifically, (a) a lectotype is designated for Hemerobius longicornis G. Gray and, as First Revisers, we selected the species name from among two that were published in the original description; (b) a lectotype is designated for Leucochrysa boxi Navás; and (c) a neotype is designated for Leucochrysa loretana Navás. Finally, the L. (L.) boxi adult is redescribed (both morphs, as well as the male and female genitalia); the larvae (all instars) are described; and aspects of the biology of the species (geographic variation in the polymorphism and a new record of ectoparasitism) are presented. Copyright © 2011 · Magnolia Press. Source

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