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1.
Ecology ; 98(3): 861-874, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28039867

RESUMEN

Biological invasions are a threat to global biodiversity and provide unique opportunities to study ecological processes. Population bottlenecks are a common feature of biological invasions and the severity of these bottlenecks is likely to be compounded as an invasive species spreads from initial invasion sites to additional locations. Despite extensive work on the genetic consequences of bottlenecks, we know little about how they influence microbial communities of the invaders themselves. Due to serial bottlenecks, invasive species may lose microbial symbionts including pathogenic taxa (the enemy release hypothesis) and/or may accumulate natural enemies with increasing time after invasion (the pathogen accumulation and invasive decline hypothesis). We tested these alternate hypotheses by surveying bacterial communities of Argentine ants (Linepithema humile). We found evidence for serial symbiont bottlenecks: the bacterial community richness declined over the invasion pathway from Argentina to New Zealand. The abundance of some genera, such as Lactobacillus, also significantly declined over the invasion pathway. Argentine ants from populations in the United States shared the most genera with ants from their native range in Argentina, while New Zealand shared the least (120 vs. 57, respectively). Nine genera were present in all sites around the globe possibly indicating a core group of obligate microbes. In accordance with the pathogen accumulation and invasive decline hypothesis, Argentine ants acquired genera unique to each specific invaded country. The United States had the most unique genera, though even within New Zealand these ants acquired symbionts. In addition to our biogeographic sampling, we administered antibiotics to Argentine ants to determine if changes in the micro-symbiont community could influence behavior and survival in interspecific interactions. Treatment with the antibiotics spectinomycin and kanamycin only slightly increased Argentine ant interspecific aggression, but this increase significantly decreased survival in interspecific interactions. The survival of the native ant species also decreased when the symbiotic microbial community within Argentine ants was modified by antibiotics. Our work offers support for both the enemy release hypothesis and that invasive species accumulate novel microbial taxa within their invaded range. These changes appear likely to influence invader behavior and survival.


Asunto(s)
Hormigas/fisiología , Especies Introducidas , Simbiosis , Animales , Argentina , Nueva Zelanda
2.
Proc Biol Sci ; 283(1832)2016 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-27306055

RESUMEN

Invasive species have an enormous global impact, with international trade being the leading pathway for their introduction. Current multinational trade deals under negotiation will dramatically change trading partnerships and pathways. These changes have considerable potential to influence biological invasions and global biodiversity. Using a database of 47 328 interceptions spanning 10 years, we demonstrate how development and governance socio-economic indicators of trading partners can predict exotic species interceptions. For import pathways associated with vegetable material, a significantly higher risk of exotic species interceptions was associated with countries that are poorly regulated, have more forest cover and have surprisingly low corruption. Corruption and indicators such as political stability or adherence to rule of law were important in vehicle or timber import pathways. These results will be of considerable value to policy makers, primarily by shifting quarantine procedures to focus on countries of high risk based on their socio-economic status. Further, using New Zealand as an example, we demonstrate how a ninefold reduction in incursions could be achieved if socio-economic indicators were used to select trade partners. International trade deals that ignore governance and development indicators may facilitate introductions and biodiversity loss. Development and governance within countries clearly have biodiversity implications beyond borders.


Asunto(s)
Comercio/legislación & jurisprudencia , Regulación Gubernamental , Especies Introducidas/legislación & jurisprudencia , Biodiversidad , Nueva Zelanda , Riesgo
3.
Proc Biol Sci ; 280(1772): 20132157, 2013 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-24266038

RESUMEN

Neurotoxic pesticides, such as neonicotinoids, negatively affect the cognitive capacity and fitness of non-target species, and could also modify interspecific interactions. We tested whether sublethal contamination with neonicotinoid could affect foraging, colony fitness and the outcome of behavioural interactions between a native (Monomorium antarcticum) and an invasive ant species (Linepithema humile). The foraging behaviour of both ants was not affected by neonicotinoid exposure. Colonies of the invasive species exposed to the neonicotinoid produced significantly fewer brood. In interspecific confrontations, individuals of the native species exposed to the neonicotinoid lowered their aggression towards the invasive species, although their survival probability was not affected. Exposed individuals of the invasive species interacting with non-exposed native ants displayed increased aggression and had their survival probability reduced. Non-exposed individuals of the invasive species were less aggressive but more likely to survive when interacting with exposed native ants. These results suggest that non-target exposure of invaders to neonicotinoids could either increase or decrease the probability of survival according to the exposure status of the native species. Given that, in any community, different species have different food preferences, and thus different exposure to pesticides, non-target exposure could potentially change the dynamics of communities and influence invasion success.


Asunto(s)
Hormigas/efectos de los fármacos , Hormigas/fisiología , Especies Introducidas , Agresión/efectos de los fármacos , Animales , Imidazoles/toxicidad , Insecticidas/toxicidad , Neonicotinoides , Nueva Zelanda , Nitrocompuestos/toxicidad , Especificidad de la Especie
5.
R Soc Open Sci ; 8(7): 201854, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34377503

RESUMEN

Degraded pasture is a major liability in Brazilian agriculture, but restoration and recovery efforts could turn this area into a new frontier to both agricultural yield expansion and forest restoration. Currently, rural properties with larger degraded pasture areas are associated with higher levels of technical inefficiency in Brazil. The recovery of 12 million ha of degraded pastures could generate an additional production of 17.7 million bovines while reducing the need for new agricultural land. Regional identification of degraded pastures would facilitate the targeting of agricultural extension and advisory services and rural credit efforts aimed at fostering pasture recovery. Since only 1% of Brazilian municipalities contain 25% of degraded pastures, focusing pasture recovery efforts on this small group of municipalities could generate considerable benefits. More efficient allocation of degraded and native pastures for meat production and forest restoration could provide land enough to fully comply with its Forest Code requirements, while adding 9 million heads to the cattle inventory. Degraded pasture recovery and restoration is a win-win strategy that could boost livestock husbandry and avoid deforestation in Brazil and has to be the priority strategy of agribusiness sector.

6.
Sci Rep ; 10(1): 1946, 2020 02 06.
Artículo en Inglés | MEDLINE | ID: mdl-32029788

RESUMEN

Brazil is a megadiversity country with more tropical forest than any other, and is a leading agricultural producer. The technical potential to reconcile these roles by concentrating agriculture on existing farmland and sparing land for nature is well-established, but the spatial overlap of this potential with conservation priorities and institutional constraints remains poorly understood. We mapped conservation priorities, food production potential and socio-economic variables likely to influence the success of land sparing. Pasture occupies 70% of agricultural land but contributes ≤11% of the domestic food supply. Increasing yields on pasture would add little to Brazil's food supply but - if combined with concerted conservation and restoration policies - provides the greatest opportunities for reducing land demand. Our study illustrates a method for identifying municipalities where land-sparing policies are most likely to succeed, and those where further effort is needed to overcome constraints such as land tenure insecurity, lack of access to technical advice, labour constraints, and non-compliance with environmental law.

7.
Braz. arch. biol. technol ; 63: e20180734, 2020. tab, graf
Artículo en Inglés | LILACS | ID: biblio-1132202

RESUMEN

Abstract Fibromyalgia (FM) is a nonarticular rheumatic syndrome that leads to diffuse myalgia, sleep disturbances and morning stiffness. Balneotherapy has been shown an effective strategy to improve the health conditions of patients; however, the treatment follow-up is based on patient report due to the lack of biomarkers. Thus, this study evaluated the application of cytokines and phosphoglycerate mutase I (PGAM-I) to monitoring FM patient underwent to balneotherapy treatment. Eleven healthy and eleven women with FM were submitted to daily sessions of balneotherapy during 10 days. Clinical and quality of life parameters were assessed through a FIQ questionnaire. Blood levels of TNF-(, interleukins (IL-1, IL-2 and IL-10) and PGAM-I expression in patients' saliva were also evaluated. Patients with FM showed significant improvements in their clinical status after treatment. Also, FM patients has IL-10 levels lower than healthy women and the balneotherapy increased the expression of this cytokine in both groups, concomitantly to pain relief. Although inflammatory cytokines (IL-1, IL-2 and TNF-() were more expressed in FM patients than healthy patients their levels did not reduce after treatment. A slight increase of PGAM-I expression was observed. In conclusion, IL-10 levels could be a useful biomarker to balneotherapy follow-up of FM patients. However, these findings must be analyzed in a larger number of patients in order to validate IL-10 as an effective biomarker.


Asunto(s)
Humanos , Femenino , Biomarcadores , Fibromialgia/diagnóstico , Interleucina-10/sangre , Calidad de Vida , Saliva , Balneología , Fibromialgia/terapia , Estudios de Casos y Controles , Encuestas y Cuestionarios , Interleucina-1/sangre , Interleucina-2/sangre , Fosfoglicerato Mutasa/sangre
8.
Toxicon ; 92: 179-85, 2014 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-25449104

RESUMEN

Anatoxins are powerful neuromuscular blocking agents produced by some cyanobacteria. Consumption of anatoxin-producing cyanobacterial mats or the water containing them has been linked to numerous animal poisonings and fatalities worldwide. Despite this health risk, there is a poor understanding of the environmental factors regulating anatoxin production. Non-axenic Phormidium autumnale strain CAWBG557 produces anatoxin-a (ATX), homoanatoxin-a (HTX) and their dihydrogen-derivatives dihydroanatoxin-a (dhATX) and dihydrohomoanatoxin-a (dhHTX). The effects of varying nitrogen and phosphorus concentrations on the production of these four variants were examined in batch monocultures. The anatoxin quota (anatoxin per cell) of all four variants increased up to four fold in the initial growth phase (days 0-9) coinciding with the spread of filaments across the culture vessel during substrate attachment. Dihydroanatoxin-a and dhHTX, accounted for over 60% of the total anatoxin quota in each nitrogen and phosphorus treatment. This suggests they are being internally synthesised and not just derived following cell lysis and environmental degradation. The four anatoxin variants differed in their response to varying nitrogen and phosphorus concentrations. Notably, dhATX quota significantly decreased (P ≤ 0.03) when nitrogen and phosphorus concentrations were elevated (nitrogen = 21 mg L(-1); phosphorus = 3 mg L(-1)), while HTX quota increased when the phosphorus concentrations were reduced (ca. < 0.08 mg L(-1)). This is of concern as HTX has a high toxicity and anatoxin producing P. autumnale blooms in New Zealand usually occur in rivers with low water column dissolved reactive phosphorus.


Asunto(s)
Toxinas Bacterianas/biosíntesis , Medios de Cultivo/química , Cianobacterias/química , Toxinas Marinas/biosíntesis , Nitrógeno/farmacología , Fósforo/farmacología , Compuestos Bicíclicos Heterocíclicos con Puentes , Cianobacterias/efectos de los fármacos , Modelos Estadísticos , Nitrógeno/análisis , Fósforo/análisis
11.
Ciênc. rural ; 41(6): 931-934, jun. 2011. tab
Artículo en Inglés | LILACS | ID: lil-592610

RESUMEN

Leaves of copperleaf (Acalypha spp.) are greatly accepted by leaf-cutting ants and therefore used to maintain colonies in the laboratory. In order to determine the attractive potential of granulated bait of Acalypha wilkesiana leaves versus citrus pulp, currently used in commercial baits, an evaluation was performed, by using the leaf-cutting ant Atta sexdens rubropilosa as model. The handmade non-toxic baits contained powder (90 percent w/w) of either citrus pulp or A. wilkesiana were offered simultaneously in the foraging arena until the total loading of one of them. Results showed that copperleaf baits are less attractive than the citrus ones, which invalidates the viability of the substitution.


Folhas de acalifa (Acalypha spp.) são de grande aceitação pelas formigas cortadeiras e, por isso, utilizadas na manutenção de colônias em laboratório. Baseado nesses fatos, procedeu-se a uma avaliação da atratividade de isca granulada feita com folhas de Acalypha wilkesiana, usando a formiga cortadeira Atta sexdens rubropilosa como modelo, com o objetivo de determinar o seu potencial atrativo frente ao citros, atualmente utilizado na formulação comercial de iscas formicidas. Foram formuladas artesanalmente iscas atóxicas, contendo pó (90 por cento p/p) de polpa cítrica ou de A. wilkesiana. As iscas foram colocadas simultaneamente em uma arena de forrageamento até o carregamento total de uma delas. Os resultados mostram que a isca de acalifa é menos atrativa que a de citros, o que inviabiliza a substituição.

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