Search results for "DIR"
showing 10 items of 10242 documents
Rethinking the perishable: Identifying organic remains in metal objects at the Iron Age site of La Bastida de les Alcusses (Moixent, Spain)
2019
Abstract The use of certain perishable materials for handicraft, such as wood, has been underestimated in archaeological investigation due to their poor preservation. Its study through indirect evidence (other non-perishable materials, ethnographic sources) is partial, and does not account for the real importance of wood in domestic, craft and ritual contexts in past societies. In this review we reclaim the use of wood as a co-constitutive material of objects by focusing on Iron Age tools, weapons and carpentry elements from a case-study in the Western Mediterranean. We also suggest the adoption of protocols for sampling and analysing the remains of wood adhered to metal objects, which may …
First Perigondwanan record of actinolepids (Vertebrata: Placodermi: Arthrodira) from the Lochkovian (Early Devonian) of Spain and its palaeobiogeogra…
2011
Different palaeogeographic models have been proposed for the position of Laurussia ( including Baltica) and Gondwana-derived microcontinents ( including Ibero-Armorica) during Ordovician to Late Carboniferous times. Principal differences concern the presence and duration of a large ocean, the Rheic Ocean, acting as a faunal barrier between these areas. The timing of the collision of Laurussia with Gondwana and/or Gondwana-derived terranes continues to be debated. Here we present new faunal data revealing close biogeographical relations between Ibero-Armorica ("Perigondwanan" or Gondwanan derivate terranes) and Podolia (SE margin of Baltica, in Laurussia). The placoderm assemblage found in t…
Volatile-mediated foraging behaviour of three parasitoid species under conditions of dual insect herbivore attack
2016
Infochemicals play an important role in structuring intra-and interspecific interactions. Many parasitoid wasp species rely on herbivory or oviposition-induced plant volatiles (HIPVs/OIPVs) to locate their herbivorous hosts, and must cope with variation in the volatile blends due to factors such as plant/host species, herbivore density or attack by several herbivores. However, little is known about how dual herbivory or changes in herbivore density affect multiple parasitoid species, each attacking a different herbivore, in the same system. In a natural system, we investigated the effect of dual attack on the ability of three parasitoid species to differentiate between volatiles induced by …
Characterization of recruitment through tandem running in an Indian queenless ant Diacamma indicum
2017
Tandem running is a primitive recruitment method employed by many ant genera. This study characterizes this behaviour during the recruitment of colony mates to a new nest in an Indian antDiacamma indicum. Tandem leaders who have knowledge of the new nest lead a single follower at a time, to the destination by maintaining physical contact. In order to characterize tandem running, we captured and analysed 621 invitations, 217 paths and 226 termination events. Remarkably, not a single colony member was lost. While invitations were stereotypic in behaviour, termination was not. Analysis of speed revealed that the average transport speed was 4.2 cm s−1. Coupled adult-brood transport was slower t…
Assessment of the conservation status of the mat-forming lichens Cladonia subgenus Cladina in Italy
2015
Cladina species are likely to suffer the impact of human pressure, resulting in a potential, as well as currently unknown, extinction risk for some of them. In this study, we used herbarium specimen data and literature data combined with geographic information system (GIS)-based analyses to assess the threatened status of Italian Cladina species according to IUCN criteria. A total of 485 records, reported during the period 1833–2013, were evaluated. Biological traits, habitat requirements and distribution patterns were used to infer species extinction risk. Extent of occurrence and area of occupancy have been calculated at the national scale, based on a 2 km × 2 km cell grid. The potential …
Effect of substitutions of key residues on the stability and the insecticidal activity of Vip3Af from Bacillus thuringiensis
2021
Modern agriculture demands for more sustainable agrochemicals to reduce the environmental and health impact. The whole process of the discovery and development of new active substances or control agents is sorely slow and expensive. Vegetative insecticidal proteins (Vip3) from Bacillus thuringiensis are specific toxins against caterpillars with a potential capacity to broaden the range of target pests. Site-directed mutagenesis is one of the most approaches used to test hypotheses on the role of different amino acids on the structure and function of proteins. To gain a better understanding of the role of key amino acid residues of Vip3A proteins, we have generated 12 mutants of the Vip3Af1 …
Evolutionary constraints of warning signals: A genetic trade-off between the efficacy of larval and adult warning coloration can maintain variation i…
2016
To predict evolutionary responses of warning signals under selection, we need to determine the inheritance pattern of the signals, and how they are genetically correlated with other traits contributing to fitness. Furthermore, protective coloration often undergoes remarkable changes within an individual's lifecycle, requiring us to quantify the genetic constraints of adaptive coloration across all the relevant life stages. Based on a 12 generation pedigree with > 11,000 individuals of the wood tiger moth (Arctia plantaginis), we show that high primary defense as a larva (large warning signal) results in weaker defenses as adult (less efficient warning color), due to the negative genetic cor…
Direct and correlated responses to bi-directional selection on pre-adult development time in Drosophila montana.
2019
Selection experiments offer an efficient way to study the evolvability of traits that play an important role in insects’ reproduction and/or survival and to trace correlations and trade-offs between them. We have exercised bi-directional selection on Drosophila montana flies’ pre-adult development time under constant light and temperature conditions for 10 generations and traced the indirect effects of this selection on females’ diapause induction under different day lengths, as well as on the body weight and cold tolerance of both sexes. Overall, selection was successful towards slow, but not towards fast development. However, all fast selection line replicates showed at the end of selecti…
Effects of plant density and cutting-type on rooting and growth of an extensive green roof of Sedum sediforme (Jacq.) Pau in a Mediterranean environm…
2020
Abstract Species of the Sedum genus are a popular choice for green roofs as they thrive in shallow growth layers and are resilient to extreme environmental conditions; they are also easy to propagate from seed, plantlings or plant parts. The use of rooted cuttings is most widespread due to good rates of establishment. In the interest of cost reduction, the direct spreading of Sedum cuttings over the roof area, especially over large areas, has attracted attention in recent years. Considering the interest on the above method and the seeming lack of experimental data available, this study aims to further knowledge in this area. Experimental tests on direct spreading of unrooted cuttings of Sed…
Love at first sniff: a spermatophore-associated pheromone mediates partner attraction in a collembolan species
2017
Mate choice is essential in most animals, as a good choice of mating partner largely determines reproductive success. Much evidence shows that olfactory cues play an important role in mate choice. However, the integration of chemical, visual and acoustic cues, often used when both partners meet, makes it hard to test whether olfaction alone can mediate reproductive decisions. Interestingly, several invertebrates have adopted a mating system where males deposit their sperm (packed in spermatophores) in the environment for females to pick up with no visual contact between the sexes. In this case the male cue is conveyed by the spermatophore only. Earlier studies on a species with indirect spe…