Search results for "tit"
showing 10 items of 26608 documents
Propagule pressure increase and phylogenetic diversity decrease community’s susceptibility to invasion
2017
Background Invasions pose a large threat to native species, but the question of why some species are more invasive, and some communities more prone to invasions than others, is far from solved. Using 10 different three-species bacterial communities, we tested experimentally if the phylogenetic relationships between an invader and a resident community and the propagule pressure affect invasion probability. Results We found that greater diversity in phylogenetic distances between the members of resident community and the invader lowered invasion success, and higher propagule pressure increased invasion success whereas phylogenetic distance had no clear effect. In the later stages of invasion,…
Private information alone can trigger trapping of ant colonies in local feeding optima.
2015
Ant colonies are famous for using trail pheromones to make collective decisions. Trail pheromone systems are characterised by positive feedback, which results in rapid collective decision making. However, in an iconic experiment, ants were shown to become 'trapped' in exploiting a poor food source, if it was discovered earlier. This has conventionally been explained by the established pheromone trail becoming too strong for new trails to compete. However, many social insects have a well-developed memory, and private information often overrules conflicting social information. Thus, route memory could also explain this collective 'trapping' effect. Here, we disentangled the effects of social …
Evolution of the Dentition in Holocephalans (Chondrichthyes) Through Tissue Disparity
2020
Abstract The Holocephali is a major group of chondrichthyan fishes, the sister taxon to the sharks and rays (Elasmobranchii). However, the dentition of extant holocephalans is very different from that of the elasmobranchs, lacking individual tooth renewal, but comprising dental plates made entirely of self-renewing dentine. This renewal of all tissues occurs at the postero-lingual plate surface, as a function of their statodont condition. The fossil record of the holocephalans illuminates multiple different trends in the dentition, including shark-like teeth through to those with dentitions completely lacking individual teeth. Different taxa illustrate developmental retention of teeth but w…
Effect of fruit-set time on the quality performance of Anona cherimola Mill. fruit in south italy
2019
Abstract The aim of this work was to analyse the differences between fruits obtained by different dates of fruit set and identify the proper fruit-set time that allows to obtain the optimum fruit quality in Annona cherimola cv Fino de Jete, planted in Southern Italy. Six fruit-set dates were selected from the first week of June to the second week of July. Fruits were sampled from October to November, when 1500 Growing Degree Days (DD) were accumulated; The DD were calculated using a base temperature of 12 °C. Fruit fresh weight (FW) and skin colour were measured. These parameters were measured also after storage, and in addition, the following parameters were measured: fruit shape (FS), pul…
Inter- and intra-specific genomic divergence in Drosophila montana shows evidence for cold adaptation
2018
This work was supported by the Academy of Finland to AH (projects 132619 and 267244) and to MK (projects 268214 and 272927) and NERC (UK) funding to MGR (grants NE/E015255/1 and NE/J020818/1) and PhD studentship to DJP (NE/I528634/1). The genomes of species that are ecological specialists will likely contain signatures of genomic adaptation to their niche. However, distinguishing genes related to ecological specialism from other sources of selection and more random changes is a challenge. Here we describe the genome of Drosophila montana, which is the most extremely cold-adapted Drosophila species. We use branch tests to identify genes showing accelerated divergence in contrasts between col…
Low but contrasting neutral genetic differentiation shaped by winter temperature in European great tits.
2016
Gene flow is usually thought to reduce genetic divergence and impede local adaptation by homogenising gene pools between populations. However, evidence for local adaptation and phenotypic differentiation in highly mobile species, experiencing high levels of gene flow, is emerging. Assessing population genetic structure at different spatial scales is thus a crucial step towards understanding mechanisms underlying intraspecific differentiation and diversification. Here, we studied the population genetic structure of a highly mobile species - the great tit Parus major - at different spatial scales. We analysed 884 individuals from 30 sites across Europe including 10 close-by sites (< 50 km), u…
Amendment of the type locality of the endemic Sicilian pond turtle Emys trinacris Fritz et al. 2005, with some notes on the highest altitude reached …
2016
The type locality of the Sicilian pond turtle Emys trinacris is here amended, and its correct name and geographical coordinates are provided. The locus typicus of the species lies at 1007 m a.s.l., i.e. nearly 400 m below what previously thought. The updated altitudinal distribution range of the species, based on verified published localities only, is between 0 and 1036 m a.s.l.
Postmating–prezygotic isolation between two allopatric populations of Drosophila montana: fertilisation success differs under sperm competition
2016
This study was funded by the Academy of Finland (grant 250999 to O. A.-H.). Postmating but prezygotic (PMPZ) interactions are increasingly recognized as a potentially important early-stage barrier in the evolution of reproductive isolation. A recent study described a potential example between populations of the same species: single matings between Drosophila montana populations resulted in differential fertilisation success because of the inability of sperm from one population (Vancouver) to penetrate the eggs of the other population (Colorado). As the natural mating system of D. montana is polyandrous (females remate rapidly), we set up double matings of all possible crosses between the sa…
Speciation in the Brachionus plicatilis Species Complex
2017
The Brachionus plicatilis species complex is the best-studied example among rotifers where the use of integrative taxonomy, coupling morphology, ecology, physiology, cross-mating experiments, and DNA taxonomy helps disentangling the biological reality of the different species in the complex. Here we review the theoretical and empirical approaches in species definition applied to the B. plicatilis complex, we outline the history of the discovery of the complex, and we explore the evidence in support of the currently accepted presence of 15 species. We review the evidence for long-distance dispersal and for co-occurrence of the species in the complex, including the processes favoring the co-o…
Oxygen Availability during Growth Modulates the Phytochemical Profile and the Chemo-Protective Properties of Spinach Juice.
2018
Fruits and vegetables are a good source of potentially biologically active compounds. Their regular consumption in the human diet can help reduce the risk of developing chronic diseases such as cardiovascular diseases and cancer. Plants produce additional chemical substances when subject to abiotic stress or infected by microorganisms. The phytochemical profile of spinach leaves (Spinacia oleracea L.), which is a vegetable with widely recognized health-promoting activity, has been affected by applying root hypoxic and re-oxygenation stress during plant growth. Leaf juice at different sampling times has been subject to liquid chromatography mass spectrometry (LC-MSn) analysis and tested on t…