The process of domestication in Triatominae

International audienc

Wing symmetry and flight activity

We compared bilateral structures (wings) of flying versus non-flying insects in two lines of #P. megistus$ which differed only by their laboratory maintenance time : PM1 (more than five generations in insectarium) and PM2 (one or two generations under laboratory conditions). Insects were processed according to Schofield (1980) and observed through a period of 30 days. During this time the insects that had flight (gf, for "good" flyers) and their wings extracted for morphometry. At the end of this period the same number of insects that did not fly (bf, for "bad" flyers), were used as a control and submitted to the same analysis. Fluctuating asymmetry (FA) was estimated at nine distances (A, B, C, D, E, H, 1, 2 and 3). FA occurs as a result of random deviations in the developement of bilaterally symmetric traits, and is considered as a useful trait for monitoring stress in the laboratory and in natural environments (Parsons, 1990). For each sample, FA values were calculated for each character as the sum of the squared signed differences between sides divided by the number of individuals sampled, i.e., ((Li-Ri)2)/N). This is equivalent to index 5 of Palmer and Strobek (1986) which they state is best able to discriminate true differences in FA. As the index to estimate asymmetry is a variance, differences between samples were tested for significance using tests of homogeneity of variances (Ho : s1=s2). Due to low sample size, statistical analysis was not applied to PM2 females (only two individuals). The PM1 bf females (6 insects) were more asymmetric than their gf counterparts (5 insects) at four wings traits (2,3 in PM1 and 2 in PM2) (gf=7 insects and bf=7 insects). Conversely, one character out of nine was found more asymmetric in gf either from PM1 (character 3 for PM1 females and E for PM1 males) or PM2 males (character D). (Résumé d'auteur

The effect of relative humidity on the behaviour and development of Triatoma brasiliensis

The preference for relative humidity (RH) and suitability of different levels of this environmental parameter were investigated in the haematophagous bug Triatoma brasiliensis Neiva, 1911 (Hemiptera, Reduviidae). The hygropreference of T. brasiliensis was studied using a RH gradient and the effect of different RHs on the egg hatching, nymph mortality and moulting success was also analysed. The results show that egg hatching in first-instar nymphs of T. brasiliensis was lower at extreme RHs and, particularly, it was lowest at 9.3% RH. The survival of starved nymphs was not affected by RH, but the percentage of engorged nymphs and the ecdysis success of these nymphs once fed was diminished strongly by high humidity. Fourth-instar nymphs preferred to stay at the lowest RH during the first 5 days after feeding and during ecdysis. This preference changed markedly during starvation. Fifteen days after ecdysis, the bugs moved towards intermediate humidities, and 30 days after ecdysis they even preferred the most humid sectors of the gradient. Females preferred to lay eggs in dry environments, suggesting that they may not have a particular hygropreference for oviposition, but that they simply lay their eggs at the RHs where they prefer to stay.Fil:Lazzari, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Lorenzo, M.G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Validation study of the Italian brief version of the multidimensional jealousy scale: Psychometric properties, measurement invariance across gender, and convergent validity

INTRODUCTION: The multidimensional jealousy scale (MJS) is among the most internationally used instruments for the assessment of jealousy in its three dimensions: cognitive, emotional, and behavioral. This study aimed to replicate the Italian validation process of the shortened MJS in order to confirm its psychometric properties and measurement invariance across gender. MATERIALS AND METHODS: Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were conducted in a large sample of adults (n = 2,928). To reliably estimate mean differences across gender, the measurement invariance of the scale was first established by means of CFA. Convergent validity was than tested by administrating the tool to a convenient sample (n = 304). RESULTS: A 15-item version of the Italian MJS was retained in its three-factor structure. The tool showed good fit with both the CFA (χ(2) = 211.827, CFI = 0.969, TLI = 0.959, RMSEA = 0.047, RMSEA 90% CI = 0.039–0.055) and the results confirmed the strong measurement invariance of the MJS across gender. The internal consistency measures were found to be fully satisfactory. Predictive associations with constructs such as avoidance and anxiety referred to attachment in relationships (ECR-R), obsessive jealousy, depressive jealousy, jealousy associated with separation anxiety, paranoid jealousy (QUEGE), and basic self-esteem (BSE) were confirmed. DISCUSSION: The MJS is particularly apt to collect information quickly and efficiently about jealousy in a current relationship. The multidimensional and brief structure makes it particularly suitable for preliminary screening, couple therapy assessment, and research purposes

Influence of Cognitive Orientation and Attentional Focus on Pain Perception

Background. Recently, a growing interest has emerged in the role of attention and hypervigilance in the experience of pain. Shifting attention away from pain seems likely to reduce the perception of pain itself. Objectives. The present study has been designed to test the following overall hypotheses: (1) disposition to catastrophize, self-efficacy perceived in pain resistance (task self-efficacy), previous experiences concerning the tolerance of physical pain, and degree of impulsiveness are significant predictors of the decision to abandon a painful test such as the cold pressor test (CPT); (2) the manipulation of the attentive focus (internal or external) can influence the level of perceived pain. Methods. Effects of the manipulation of attentional focus (internal and external) on pain perception and response of trial abandonment were evaluated in a sample of university students (n = 246) subjected to the cold pressor test. Results. A significant effect (p < 0.05) was found through a test–retest comparison on the final level of perceived pain among subjects who had received instruction to externalize the focus of their attention (mixed factorial analysis of variance), but no significance was observed with respect to the decision to abandon the experiment. A general explanatory model of the abandonment behavior demonstrating overall good fit measurements was tested too. Conclusion. The abandonment of tests has been shown to be predicted mainly by catastrophic attitude. Attentive impulsiveness showed a further positive effect on catastrophic attitude. Perceived self-efficacy in the tolerance of pain limited learned helplessness, which in turn positively influenced catastrophizing