Search results for "Meter"

Foraging behaviour of an egg parasitoid exploiting plant volatiles induced by pentatomids : The role of adaxial and abaxial leaf surfaces

2017

Several phases of herbivorous insect attack including feeding and oviposition are known to induce plant defenses. Plants emit volatiles induced by herbivores to recruit insect parasitoids as an indirect defense strategy. So far, volatiles induced by herbivore walking and their putative role in the foraging behavior of egg parasitoids have not been investigated. In this paper we studied the response of the egg parasitoid Trissolcus basalis toward volatiles emitted by Vicia faba plants as consequence of the walking activity of the host Nezara viridula. Olfactometer bioassays were carried out to evaluate wasp responses to plants in which the abaxial or the adaxial surfaces were subjected to wa…

Lysimeter assessment of the Simplified Two-Source Energy Balance model and eddy covariance system to estimate vineyard evapotranspiration

2019

Abstract Estimation of crop water needs plays a key role in the water resource management in arid and semi-arid regions. Actual evapotranspiration (ETa) becomes the key term in both water and energy balances at this point. In this work we focus on vineyard due to the significance of this crop for La Mancha region, Spain, with the greatest concentration of vineyards in the world. Eddy-covariance (EC) technique has been traditionally used for ground observations of ETa. One of the aims of this work is to assess the feasibility of an EC system under the challenging conditions of a small drip-irrigated vineyard in a semi-arid environment. Two-source energy balance modelling allows for ETa estim…

Regional endothermy as a trigger for gigantism in some extinct macropredatory sharks

2017

Otodontids include some of the largest macropredatory sharks that ever lived, the most extreme case being Otodus (Megaselachus) megalodon. The reasons underlying their gigantism, distribution patterns and extinction have been classically linked with climatic factors and the evolution, radiation and migrations of cetaceans during the Paleogene. However, most of these previous proposals are based on the idea of otodontids as ectothermic sharks regardless of the ecological, energetic and body size constraints that this implies. Interestingly, a few recent studies have suggested the possible existence of endothermy in these sharks thus opening the door to a series of new interpretations. Accord…

Native egg parasitoids recorded from the invasive Halyomorpha halys successfully exploit volatiles emitted by the plant–herbivore complex

2017

When an accidentally introduced pest establishes in the invaded area, native natural enemies may adapt to the new host. A decade after the accidental introduction of the brown marmorated stink bug, Halyomorpha halys, in Europe, two generalist native egg parasitoids, the eupelmid Anastatus bifasciatus and the encyrtid Ooencyrtus telenomicida, have been recorded from this invasive agricultural pest in the field. Both species are able to complete development to the adult stage within the new host. Trissolcus basalis (Platygastridae = Scelionidae), which is not associated with H. halys in the field, was reared from freeze-killed sentinel eggs placed on soybean plants in central Italy. We tested…

Vibration Monitoring of the Mechanical Harvesting of Citrus to Improve Fruit Detachment Efficiency

2019

The introduction of a mechanical harvesting process for oranges can contribute to enhancing farm profitability and reducing labour dependency. The objective of this work is to determine the spread of the vibration in citrus tree canopies to establish recommendations to reach high values of fruit detachment efficiency and eliminate the need for subsequent hand-harvesting processes. Field tests were carried out with a lateral tractor-drawn canopy shaker on four commercial plots of sweet oranges. Canopy vibration during the harvesting process was measured with a set of triaxial accelerometer sensors with a datalogger placed on 90 bearing branches. Monitoring of the vibration process, fruit pro…

An assessment of the floristic composition, structure and possible origin of a liana forest in the Guayana Shield

2015

Liana is a life form that possess high importance in many neotropical forests. Density of climbers apparently increases with the intervention rate (eg. logging). The aim of this work is to characterize the structure, floristic composition and soils of a sector classified as Liana Forest (LF). We identified a LF sector in a not-logged area; three 1 ha square plots were measured (individuals ≥ 10 cm dbh, “diameter at breast height”). In each plot we evaluate four 100 m2 square understory sub-plots (all spermatophyta individuals < 10 cm dbh). LF has a low canopy (< 15 m) and is dominated by Alexa imperatricis and Pentaclethra macroloba. Basal area (20.4 m2ha-1) and diversity (H´= 2.6) ar…

Larger cell or colony size in winter, smaller in summer – a pattern shared by many species of Lake Kinneret phytoplankton

2017

We examined an 8.5-year record (2004-2012) of cell size data for phytoplankton species from Lake Kinneret, Israel, sampled weekly or at 2-week intervals and determined microscopically by the same person. Many of the species abundant enough to be counted year-round showed a typical seasonal cell size pattern that repeated annually: cell diameter was maximal in winter and minimal in summer. This pattern was shared by species from different taxonomic groups including cyanobacteria, chlorophyta, and dinoflagellates. Similarly, in colonial species of diatoms, chlorophyta, and cyanobacteria the number of cells per colony was larger in winter and smaller in summer. We postulated that the seasonal …

2020

Necrobia rufipes (De Geer) (Coleoptera: Cleridae), also known as the red-legged ham beetle, is a newly emerging pest of pet food stores, causing apprehension among producers worldwide. Concerns about this pest are exacerbated by the lack of information about infestation modalities in pet food, while specific monitoring tools are missing. Considering that adequate pet food packaging could limit N. rufipes infestations, information about the penetration modalities in commonly used pet food packaging is needed. Moreover, the development of appropriate monitoring instruments is urgent to detect pest presence early and to reduce chemical treatments for its control. In this paper, the adults’ and…

Surgical implantation of electronic tags does not induce medium-term effect: insights from growth and stress physiological profile in two marine fish…

2020

Abstract Background Telemetry applied to aquatic organisms has recently developed greatly. Physiological sensors have been increasingly used as tools for fish welfare monitoring. However, for the technology to be used as a reliable welfare indicator, it is important that the tagging procedure does not disrupt fish physiology, behaviour and performance. In this communication, we share our medium-term data on stress physiological profile and growth performance after surgical tag implantation in two important marine fish species for European aquaculture, the sea bream (Sparus aurata) and the European sea bass (Dicentrarchus labrax). Results Blood samples after surgical tag implantation (46 day…

Halophila stipulacea descriptors in the native area (Red Sea): A baseline for future comparisons with native and non-native populations

2018

Abstract Halophila stipulacea is a small tropical seagrass species native to the Red Sea. Due to its invasive character, there is growing interest in understanding its ability to thrive in a broad range of ecological niches. We studied temporal (February 2014 and July 2014), depth (5, 9, 18 m) and spatial (NB and SB) related dynamics of H. stipulacea meadows in the northern Gulf of Aqaba. We evaluated changes in density, morphometry, biomass, and biochemical parameters alongside the reproductive effort. In both sites, maximal growth and vegetative performance occurred in the summer with a marked increase of 35% in shoot density and 18% in biomass; PAR reduction with season and depth induced…