1,721,145 research outputs found
Polistes dominulus wasps (Hymenoptera Vespidae), if parasitized by Xenos vesparum (Strepsiptera Stylopidae), wander among nests during the pre-emergence phase
No full textThis study is focused on the spatial behaviour of overwintered Polistes dominulus wasps, either unparasitized or parasitized by Xenos vesparum (Strepsiptera). The neotenic female endoparasites protrude their cephalothorax from the host abdomen and, after winter diapause, hundreds of 1(st) instar larvae, the infective free-living stage, emerge alive and move from the brood canal of the cephalothorax to the substrate. We carried out spring transects along artificial hibernation/nesting sites showing a high site-attachment of healthy wasps before and mainly after nest foundation, whereas parasitized ones moved from one colony to another just when wasp larvae, the target of infection, are present in nests. These data support the hypothesis of a direct release of Xenos larvae on/close to nests although phoresy, assumed as the usual infection mechanism for Strepsipterans, is also possible. RI Massolo, Alessandro/I-3437-201
Sex identification in female crayfish is bimodal
No full textSex identification has been studied in several species of crustacean decapods but only seldom was the role of multimodality investigated in a systematic fashion. Here, we analyse the effect of single/combined chemical and visual stimuli on the ability of the crayfish Procambarus clarkii to identify the sex of a conspecific during mating interactions. Our results show that crayfish respond to the offered stimuli depending on their sex. While males rely on olfaction alone for sex identification, females require the combination of olfaction and vision to do so. In the latter, chemical and visual stimuli act as non-redundant signal components that possibly enhance the female ability to discriminate potential mates in the crowded social context experienced during mating period. This is one of the few clear examples in invertebrates of non-redundancy in a bimodal communication system. RI Massolo, Alessandro/I-3437-201
Predatory behaviour on ground beetles (Coleoptera : Carabidae) by Ocypus olens (Muller) (Coleoptera : Staphylinidae) under laboratory conditions
No full textWe studied the prey preference and feeding behaviour of adult males of Ocypils olens (Muller) (Coleoptera: Staphylinidae), an active predator of many insects, under laboratory conditions, Tests were carried out individually on eight types of carabid beetles: three species with chemical defences and aposematic colours, Brachinus sclopeta (Fabricius, 1792), Anchomenus dorsalis (Pontoppidan, 1763) and Chlaenius velutinus (Duftschmid, 1812), and five species without these characteristics, Pseudophonus rufipes (De Geer, 1774), Sterolms melas italicus (Dejean, 1828), Amara anthobia Villa & Villa, 1833, Poecilus cupreus (Linne, 1758) and Calathus fuscipes (Goeze, 1777). Ocvpus olens preferred to attack prey without chemical defences and aposematic colour patterns, possibly stimulated by the prey's type of movement. RI Massolo, Alessandro/I-3437-201
Sexual and individual cues in the peri-anal gland secretum of crested porcupines (Hystrix cristata)
No full textAs for other rodents, peri-anal glands are well developed in the crested porcupine Hystrix cristata. Their waxy secretion has a Peculiar odour, usually perceivable around the dens. Male African H. africaeaustralis use this secretion to mark feeding sites in captivity, but its function in H. cristata has never been studied yet. Through live-trapping in Central Italy, we sampled gland contents of 33 freely living crested porcupines (19 males and 14 females), and, in 5 animals, 2-3 subsequent collections were made at different times.GC-MS analyses showed that the secretion volatile component is a complex mixture. mainly constituted by aliphatic Compounds. The principal constituents were saturated and unsaturated gamma-lactones, macrolactones, primary alcohols and fatty acids. The composition was similar between sexes, but for two compounds (nonadecan-1-ol and a compound tentatively identified as 16-methyl oxacyclohexadecan-2-one) that were significantly more frequent in males than in females.We compared the Squared Euclidean distances of the relative abundances of constituents in all possible couple of specimens, and found that the average distance between males and females was significantly higher than the distance between males, but significantly lower than the distance between females. We hypothesized that, although all the females were adult, this variability might be due to physiological differences between individuals (e.g. reproductive status). Using the same approach, we found that the chemical profiles of different individuals (inter-individual variability) was greater than intra-individual variability, suggesting that the peri-anal secretions may play a role in individual recognition. (C) 2008 Deutsche Gesellschaft fur S Saugetierkunde. Published by Elsevier GmbH. All rights reserved. RI Massolo, Alessandro/I-3437-201
Factors affecting habitat occupancy by wolves in northern Apennines (northern Italy): A model of habitat suitability
No full textThe expansion of the wolf population all over Europe has posed problems on wolf-man coexistence in those areas where the wolf was not present for a long time. Breeding activities are now threatened by high predation on livestock. We investigated the relationship between wolf and its habitat, in order to evaluate wolf habitat suitability and to predict its presence. The study areas covered 3289 km2. A 23 km2 grid was used to identify 143 sample squares. For each sample square 58 habitat variables were measured from land-use (1:25000), and from topographical maps. Wolf presence (4 classes) was assessed by scat collection, direct observations, snow tracking, wolf-howling, and predation records. Univariate and multivariate statistical analyses were carried out to investigate the influence of habitat features on wolf presence. The habitat suitability model was based on two different equations: a dichotomous logistic regression model, and a polytomous one. The first one discriminated between suitable and unsuitable habitats, and its predictions were confirmed in 93% of grouped cases; the second provided predicted values of wolf presence that were concordant with the observed response levels in 82.5% of contrasts. Both models underlined the importance of three factors in determining wolf habitat suitability: wild prey abundance, human presence and forest cover. RI Massolo, Alessandro/I-3437-201
Agonistic behaviour of Scarites buparius (Forster, 1771) (Coleoptera : Carabidae) in relation to body size
No full textIntra-male aggressive behaviour of Scarites buparius was analysed; agonistic interaction between males consisted of a repeated series of fighting events. We defined this behaviour as "agonistic" because a dominance/submission status was established. We measured the males and found that the attack behaviour persistence is correlated with the body length. RI Massolo, Alessandro/I-3437-201
Long-lasting effects of sublingual immunotherapy for house dust mites in allergic rhinitis with bronchial hyperreactivity: A long-term (13-year) retrospective study in real life
No full textBackground: Subcutaneous immunotherapy for respiratory allergy has shown a long lasting efficacy after its discontinuation, whereas evidence in the case of sublingual immunotherapy (SLIT) is weak. This retrospective study evaluates whether SLIT exerts a long-lasting effect and whether it relates to its duration. Methods: Sixty-five patients allergic to mite and positive to methacholine challenge 13 years ago were studied. Twelve (control group, SLIT 0) were treated for 4 years only with standard pharmacological therapy (SPT), while 53 received SLIT and SPT. Among these, four groups were identified according to SLIT duration. Fifteen patients were treated for 1 year (SLIT 1), 10 for 2 (SLIT 2), 14 for 3 (SLIT 3) and 14 for 4 years (SLIT 4). Clinical parameters (symptom monthly score, SMS), bronchial reactivity and FEV1 were evaluated in 1992 (run-in), 1993 (baseline) and every 2 years from 1997 to 2005. Results: Two to 3 years after the treatment ended, a positive effect on SMS, but not methacholine challenge and FEV1, was seen in the SLIT groups versus SLIT 0. At this time interval an effect on methacholine challenge was also seen in SLIT 3. After 7-8 years a significant difference was seen for SMS, i.e., it was significantly better in SLIT 4 than in the other groups, while bronchial reactivity was still improved in SLIT 1, 3 and 4 only after 5-6 years. Conclusions: The effects of a 4-year SLIT on clinical parameters but not bronchial reactivity and FEV1 last 7-8 years after its discontinuation. SLIT shorter than 4 years yields proportionally less impressive results. Copyright (c) 2007 S. Karger AG, Basel. RI Massolo, Alessandro/I-3437-201
Social hackers: Integration in the host chemical recognition system by a paper wasp social parasite
No full textObligate social parasites in the social insects have lost the worker caste and the ability to establish nest. As a result, parasites must usurp a host nest, overcome the host recognition system, and depend on the host workers to rear their offspring. We analysed cuticular hydrocarbon profiles of live parasite females of the paper wasp social parasite Polistes sulcifer before and after usurpation of host nests, using the non-destructive technique of solid-phase micro-extraction. Our results reveal that hydrocarbon profiles of parasites change after usurpation of host nests to match the cuticular profile of the host species. Chemical evidence further shows that the parasite queen changes the odour of the nest by the addition of a parasite-specific hydrocarbon. We discuss the possible role of this in the recognition and acceptance of the parasite and its offspring in the host colony. RI Massolo, Alessandro/I-3437-201
A wolf habitat suitability prediction study in Valais (Switzerland)
No full textIn recent years, the European wolf (Canis lupus) population has expanded its southern range from the Italian Peninsula to the Maritime Alps (Italy and France) and to Piemonte (Italy); establishing small sub-populations. Hence re-colonisation of the Swiss Alps is now likely to occur. In 1995-1996 the wolf reached the southern part of Switzerland (Canton of Valais) from where he got extinct 150 years ago. Actual conflicts of interests between livestock breeders, local political authorities and nature conservation parties, as well as federal authorities defending the protected status of wolf, require serious management investigations. In order to check wolf habitat suitability of an alpine landscape, like the Valais, subjected to dynamic landscape-ecology processes since the extinction of wolf, we present herein an application of a predictive wolf habitat model, using a stochastic model involving logistic regression. As no data were available in the Canton of Valais, the regression coefficients for the retained variables such as urban area, population density, arable land, minimal altitude, northwest exposure and wild ungulate diversity index, were derived from data collected in the northern Apennine (Northern Italy), where habitat variables were related to data of wolf presence. The selection of the parameters for the Canton of Valais has been performed in respect of their predictive power, as well as their availability and geo-morphological importance for the alpine landscape under consideration. Using the geographic information system (GIS), the simulation pointed out that 19% (1142 km2) of the total grid surface (5821 km2) are suitable for wolf presence. Moreover, it reveals that especially areas at lower altitudes (minimum altitude 1800-2000 m a.s.l.), due to lack of prey and severe geo-morphological conditions, present a reduced habitat suitability. The geomorphological and demographic situation of the alpine area lead to a wolf habitat of a partially fragmented and linear aspect, affecting overall habitat suitability. The strengths of the application is not only the visualisation of the present habitat quality of an alpine landscape recolonised by wolves, but also that it allows to make investigations in order to manage the different conflicts of interest. RI Massolo, Alessandro/I-3437-201
The quantification of damages caused by an infringement of Art. 101 or Art. 102 TFEU: is arbitration really a short cut?
Full text linkThe quantification of damages for a breach of Article 101 or 102 TFEU is complex, demanding and time consuming. Over the last few years, it has become one of the main issues in policy discussions within the European Union (EU). In particular, the European Commission (EC) investigated and revealed that the procedure for the quantification of
damages caused by a breach of EU antitrust laws not only requires expert economic and econometric skills, but varies from Member State to Member State. As a consequence of
this disparity, the EC issued new guidelines to render uniform the procedure for the quantification of damages caused by antitrust breaches across Member States and adopted new regulations to encourage private actions for damages. The latter aim at encouraging the use of alternative dispute resolution (ADR) methods, most notably arbitration, to resolve antitrust disputes as they provide a more expedient process and a fairer solution than a national court judgment. Furthermore, arbitration may be compared to a noncooperative or Bayesian game. Indeed, an antitrust dispute is characterised by asymmetric information. Hence, the parties thereto act strategically in order to push the arbitrator to issue a settlement in their favour. As a result, both parties are incentivized to make extreme
offers, the effect of which is to slow down the arbitration proceedings and lead the arbitrator to reach a settlement which does not correctly quantify the damages suffered.
Thus, we require a system that has the double effect of encouraging the parties to avoid adopting extreme positions and converge in their offers. The amended final offer
arbitration (AFOA) seems to comply with both these equirements. Nevertheless, the fact that it involves a punishment could prove counter-productive by discouraging the parties from actually selecting arbitration as an ADR method to resolve their disputes. Thus, to be an effective private action for damages caused by an infringement of Article 101 or 102 TFEU, arbitration must be structured in a manner that enables the arbitrator to reach a fair
settlement, encourages the parties to converge in their offers and incentivises the parties to actually select such arbitration mechanism to resolve their disputes.The quantification of damages for a breach of Article 101 or 102 TFEU is complex, demanding and time consuming. Over the last few years, it has become one of the main issues in policy discussions within the European Union (EU). In particular, the European Commission (EC) investigated and revealed that the procedure for the quantification of
damages caused by a breach of EU antitrust laws not only requires expert economic and econometric skills, but varies from Member State to Member State. As a consequence of
this disparity, the EC issued new guidelines to render uniform the procedure for the quantification of damages caused by antitrust breaches across Member States and adopted new regulations to encourage private actions for damages. The latter aim at encouraging the use of alternative dispute resolution (ADR) methods, most notably arbitration, to resolve antitrust disputes as they provide a more expedient process and a fairer solution than a national court judgment. Furthermore, arbitration may be compared to a noncooperative or Bayesian game. Indeed, an antitrust dispute is characterised by asymmetric information. Hence, the parties thereto act strategically in order to push the arbitrator to issue a settlement in their favour. As a result, both parties are incentivized to make extreme
offers, the effect of which is to slow down the arbitration proceedings and lead the arbitrator to reach a settlement which does not correctly quantify the damages suffered.
Thus, we require a system that has the double effect of encouraging the parties to avoid adopting extreme positions and converge in their offers. The amended final offer
arbitration (AFOA) seems to comply with both these equirements. Nevertheless, the fact that it involves a punishment could prove counter-productive by discouraging the parties from actually selecting arbitration as an ADR method to resolve their disputes. Thus, to be an effective private action for damages caused by an infringement of Article 101 or 102 TFEU, arbitration must be structured in a manner that enables the arbitrator to reach a fair
settlement, encourages the parties to converge in their offers and incentivises the parties to actually select such arbitration mechanism to resolve their disputes.LUISS PhD Thesi
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