Search results for "HAV"

Sole coloration as an unusual aposematic signal in a Neotropical toad

2019

Many animals have evolved remarkable strategies to avoid predation. In diurnal, toxic harlequin toads (Atelopus) from the Amazon basin, we find a unique colour signal. Some Atelopus populations have striking red soles of the hands and feet, visible only when walking. When stationary, the toads are hard to detect despite their yellow-black dorsal coloration. Consequently, they switch between high and low conspicuousness. Interestingly, some populations lack the extra colour display of the soles. We found comprehensive support that the red coloration can act as an aposematic signal directed towards potential predators: red soles are significantly more conspicuous than soles lacking red colora…

The impact of life stage and pigment source on the evolution of novel warning signal traits

2021

Our understanding of how novel warning color traits evolve in natural populations is largely based on studies of reproductive stages and organisms with endogenously produced pigmentation. In these systems, genetic drift is often required for novel alleles to overcome strong purifying selection stemming from frequency-dependent predation and positive assortative mating. Here, we integrate data from field surveys, predation experiments, population genomics, and phenotypic correlations to explain the origin and maintenance of geographic variation in a diet-based larval pigmentation trait in the redheaded pine sawfly (Neodiprion lecontei), a pine-feeding hymenopteran. Although our experiments c…

Diversity in warning coloration: selective paradox or the norm?

2019

Aposematic theory has historically predicted that predators should select for warning signals to converge on a single form, as a result of frequency-dependent learning. However, widespread variation in warning signals is observed across closely related species, populations and, most problematically for evolutionary biologists, among individuals in the same population. Recent research has yielded an increased awareness of this diversity, challenging the paradigm of signal monomorphy in aposematic animals. Here we provide a comprehensive synthesis of these disparate lines of investigation, identifying within them three broad classes of explanation for variation in aposematic warning signals: …

Hieracium umbrosum subsp. abietinum (Asteraceae), a further example of amphi-Adriatic disjunction

2017

So far considered as endemic to Greece, Hieracium umbrosum subsp. abietinum is reported as new for the Italian flora. Its presence has been noted on the Pollino National Park (S Italy). Morphological, ecological and taxonomical notes are given. This discovery increases the list of taxa showing an amphi-Adriatic distribution.

First record of Sphaeralcea bonariensis (Cav.) Griseb. (Malvaceae) as a casual alien species in the Mediterranean area

2022

Sphaeralcea bonariensis (Cav.) Griseb. is here reported for the first time as alien species in Italy and in the Mediterranean area. It is a perennial shrub native to Southern America, where it is often considered a ruderal species frequent in cultivated areas. It was found in a population of a few individuals within Opuntia ficus-indica groves of Rocca Palumba territory (Western Sicily). Actually, due to short-term observational period and the low number of plants, Sphaeralcea bonariensis should be considered as a casual species in Italy. The ecological characteristics of the growing stand and the consistency of the population, as well as the possible causes of its introduction, are briefly…

Vascular Risk Factors in Mild Cognitive Impairment Subtypes

2007

<i>Background and Aim:</i> To investigate the role of vascular risk factors in different subtypes of mild cognitive impairment (MCI) in a multicentric, clinic-based, cross-sectional study. <i>Methods:</i> Two-hundred and seven subjects with MCI were included in the study: 33 with single non-memory MCI (snmMCI), 42 with multiple-domain amnestic MCI (mdMCI-a) and 132 with amnestic MCI (aMCI). Several clinical vascular risk factors and magnetic resonance imaging (MRI) brain lesions were evaluated. <i>Results:</i> snmMCI showed a higher frequency of ischaemic heart disease and of transient ischaemic attack (TIA)/stroke, a higher Hachinski ischaemic score and …

Sofie's World : Resistance toward the Thin Ideal in Sofie Hagen's Fat Activist Online Content

2021

Behavioural adaptations of argulid parasites (Crustacea: Branchiura) to major challenges in their life cycle

2015

Fish lice (Argulus spp.) are obligate ectoparasites, which contrary to most aquatic parasites, retain the ability to swim freely throughout the whole of their life. In fish farms, they can quickly increase in numbers and without effective control cause argulosis, which results in the reduced growth and survival of their fish hosts. The morphology of Argulus spp, including their sensory organs, is suitable for both parasitism and free-swimming. By spending a considerable amount of time away from their host, these parasites risk being excessively dispersed, which could endanger mating success. Here we present a review of recent studies on the behaviour of Argulus spp, especially the aggregati…

Kasvisten, hedelmien ja marjojen syömisen lisääntyminen ryhmäohjauksessa

2017

Tämän tutkimuksen tarkoituksena oli selvittää Keski-Suomen alueella toteutettuun ryhmäohjaukseen osallistuneiden ryhmäläisten kasvisten syömistä 12 kuukauden aikana. Tavoitteena oli tutkia tuoreiden kasvisten, kypsennettyjen kasvisten sekä hedelmien ja marjojen käyttöä ja niiden syönnissä tapahtunutta muutosta. Lisäksi selvitettiin, miten sukupuoli, paino, painoindeksi, vyötärönympärys ja elämäntilanne ovat yhteydessä kasvisten syömiseen sekä miten yksilön aikomus muuttaa ruokakäyttäytymistä vaikuttaa itse muutoksen tekemiseen. Tutkimus on osa Keski-Suomen alueella toteutettua ryhmäohjausta (2011-2016) ja tutkimusaineisto kerättiin kyselylomakkeella alku- (0 kk), väli- (6 kk) ja loppumittau…

Regional metacommunities in two coastal systems: spatial structure and drivers of plant assemblages

2014

Aim Biogeographical patterns in metacommunities are still poorly understood, and different processes are expected to occur in different habitats. We analysed the regional plant metacommunities of coastal habitats to test whether (1) the influence of space and climate differs between two habitats differentiated along the seashore–inland gradient, and (2) regional variation in species composition of these habitats can be ascribed to different metacommunity paradigms. Location The entire coast of the Iberian Peninsula, south-western Europe. Methods We collected data on the plant species composition of coastal sites on sand dunes across 3000 km of coastline. The sites were classified into two h…