Search results for "BIOTIC"

Priming: getting ready for battle

2006

International audience; Infection of plants by necrotizing pathogens or colonization of plant roots with certain beneficial microbes causes the induction of a unique physiological state called “priming.” The primed state can also be induced by treatment of plants with various natural and synthetic compounds. Primed plants display either faster, stronger, or both activation of the various cellular defense responses that are induced following attack by either pathogens or insects or in response to abiotic stress. Although the phenomenon has been known for decades, most progress in our understanding of priming has been made over the past few years. Here, we summarize the current knowledge of p…

Temperature as a modulator of sexual selection

2018

A central question in ecology and evolution is to understand why sexual selection varies so much in strength across taxa; it has long been known that ecological factors are crucial to this. Temperature is a particularly salient abiotic ecological factor that modulates a wide range of physiological, morphological and behavioural traits, impacting individuals and populations at a global taxonomic scale. Furthermore, temperature exhibits substantial temporal variation (e.g. daily, seasonally and inter-seasonally), and hence for most species in the wild sexual selection will regularly unfold in a dynamic thermal environment. Unfortunately, studies have so far almost completely neglected the rol…

Synergistic reduction of a native key herbivore performance by two non-indigenous invasive algae

2019

Abstract Native generalist grazers can control the populations of non-indigenous invasive algae (NIIA). Here, it was found that the simultaneous consumption of two co-occurring NIIA, Caulerpa cylindracea and C. taxifolia var. distichophylla, hinders the grazing ability of the main Mediterranean herbivorous, the native sea urchin Paracentrotus lividus. The ingestion of any of the two NIIA alone did not produce any difference in sea urchin righting time with respect to usual algal diet. In contrast, the simultaneous consumption of both NIIA, which grow intermingled in nature and are consumed by P. lividus, retarded its righting behavior. Such result reveals substantial physiological stress in…

Nicodemia madagascariensis(Lam.) R. Parker (Family Scrophulariaceae), a casual alien plant new to Italy

2016

In this note the authors report the first case of naturalization of the Malagasy smoke bush within Italian territory. Along with a description of the abiotic and biotic characteristics of the invaded site, the current demographic and dynamic trends of the detected population by means of growth-ring analysis was also assessed. Moreover, an overview on the history of its introduction in Europe is provided, underlining the key role played by the Mediterranean cities with respect to the acclimatization and spread of alien tropical and subtropical plants. Due to its low frequency under cultivation, the Malagasy smoke bush should not behave as an invader in the future; on the other hand, its abil…

Structuring factors of the spatio-temporal variability of macrozoobenthos assemblages in a southern Mediterranean lagoon: How useful for bioindicatio…

2017

International audience; The authors investigated the impact of the extension of the El Kantra Channel on the composition and structure of macrobenthic assemblages in Boughrara Lagoon (Gulf of Gabes, Tunisia along with the use of 4 biotic indices (AMBI, BENTIX, M-AMBI and TUBI). Thirteen stations were sampled seasonally in 2012–2013. Forty-one species were found in 2012–2013 not recorded in 2009–2010, including 20 species of polychaetes belonging to the trophic groups of deposit-feeders and carnivores which are expected to increase in areas disturbed by organic pollution. During the survey, we recorded a high fish mortality, essentially caused by the development of harmful algal blooms (HAB)…

Ultra- and microplankton assemblages as indicators of trophic status in a Mediterranean lagoon

2016

International audience; The seasonal abundance distribution of heterotrophic prokaryotes, pico-and nanophytoplankton, was investigated in connection with environmental variables and microplankton abundance at five stations in Ghar El Melh Lagoon (northeastern Tunisia). Flow cytometry analysis of ultraplankton resolved (i) five heterotrophic prokaryote groups labelled LNA1, LNA2 (low nucleic acid content), HNA1, HNA2 and HNA3 (high nucleic acid content) and (ii) at least 14 ultraphytoplankton groups assigned to picoeukaryotes, picoprokaryotes, nanoeukaryotes, cryptophyte-like cells and some unknown communities. Redundancy analysis (RDA) revealed (i) autumn-summer outbreaks of heterotrophic p…

The role of watercourse versus overland dispersal and niche effects on ostracod distribution in Mediterranean streams (eastern Iberian Peninsula)

2016

Abstract The processes behind the heterogeneous distribution of species involve a combination of environmental and spatial effects. In the spatial context, stream networks constitute appropriate systems to compare the relative importance of two dispersal modes in aquatic organisms: overland and watercourse dispersal. In the present study, we analyzed the distribution of ostracod species in a river network in the eastern Iberian Peninsula, with variation partitioning between environmental and spatial factors, using Moran and Asymmetric Eigenvector Maps (MEMs, AEMs) as spatial variables. Our aims were to determine the relative importance of environmental and spatial control and to compare the…

2021

Many phytophagous insects harbor symbiotic bacteria that can be transmitted vertically from parents to offspring, or acquired horizontally from unrelated hosts or the environment. In the latter case, plants are a potential route for symbiont transfer and can thus foster a tripartite interaction between microbe, insect, and plant. Here, we focus on two bacterial symbionts of the darkling beetle Lagria villosa that belong to the genus Burkholderia; the culturable strain B. gladioli Lv-StA and the reduced-genome strain Burkholderia Lv-StB. The strains can be transmitted vertically and confer protection to the beetle’s eggs, but Lv-StA can also proliferate in plants, and both symbiont strains h…

Immunocompetence increases with larval body size in a phytophagous moth

2013

Despite the obvious benefit of an immune system, its efficacy against pathogens and parasites may show great variation among individuals, populations and species. Understanding the causes of this variation is becoming a central theme in ecology. Many biotic and abiotic factors are known to influence immunocompetence (temperature, age, etc.). However, for a given age, size among individuals varies, probably as a result of accumulated resources. Thus, these variable resources could be allocated to immune defence and, consequently, body size may explain part of the variation in immune responsiveness. However, the influence of body size on immune defence is often overlooked. The present study i…

Phytoplankton and its biotic interactions: Colin Reynolds’ legacy to phytoplankton ecologists

2019

The 18th workshop of the International Association for Phytoplankton Taxonomy and Ecology (IAP), the first ‘‘tropical’’ IAP ever, the third one outside Europe, and the first one in South America, was held in Natal, Brazil, from August 27 to September 3, 2017, and its main ecological theme was the Phytoplankton and its biotic interactions. The taxonomic topic of the workshop was chosen based on function instead of phylogeny, and to link to the ecological theme of the workshop, the taxonomic theme was therefore centered on mixotrophic microalgae.