Giorgio Celli

Population structure of Aedes albopictus (Skuse): the mosquito which is colonizing Mediterranean countries

Multilocus electrophoresis analysis has been used to study the genetic structure of 18 populations of Aedes albopictus newly introduced to Italy, in comparison with two populations in the United States, four in Japan, and four in Indonesia. Allozyme analysis revealed that 15 out of the 18 studied loci were polymorphic among the 28 populations. No significant deviations from Hardy–Weinberg equilibrium were found at polymorphic loci. High genetic affinity was observed between the Italian populations and those from the United States and Japan. The analysis of variance in allele frequencies showed that variance among subpopulations accounted for most of the total variance, suggesting that isolation of the Italian populations is not related to distance. Analysis of linkage disequilibrium using Ohta’s method shows that the variance in the frequency of allele combinations could be explained by the action of the genetic drift which accompanies the establishment of new populations. The colonization process of Ae. albopictus in Italy is following a trend similar to that previously observed in the U.S.A., probably because both infestations derive from several successive introductions, each with large numbers of individuals.

Honey bees and their products as indicators of environmental radioactive pollution

Samples of honey, pollen and honey bees have been collected in some regions of Italy after the Chernobyl accident, and subjected to gamma spectrometry in order to assess their possible use as markers of the radioactive environmental contamination. Pollen has resulted in the best indicator, since it reflects exactly the air contamination and therefore it is suitable for obtaining a map of fallout. Also bees can be used for the purpose, even if their collection is more difficult, whereas honey gives only an indication.

Tolerance Thresholds for Aedes albopictus and Aedes caspius in Italian Urban Areas

ABSTRACT With nuisance mosquito species, the goal of integrated pest management is to keep mosquito density below a tolerance level that is often set by economic, ecological, and political factors. This study compares actual human annoyance, as measured by a phone survey, with several measures of mosquito abundance, in order to determine a threshold that is both relevant and practical. The efficiency of CO2-baited traps, container index (CI), and oviposition traps for monitoring Aedes albopictus, and CO2-baited traps for monitoring Aedes caspius, was evaluated. CO2-baited traps were confirmed to be of low efficiency in Ae. albopictus collection, while correlation matrices showed a good relationship between CI and the number of eggs collected (R = 0.91), and between number of eggs and phone-survey nuisance level estimates (R = 0.88). Correlation between CI and phone-survey nuisance levels was slightly lower (R = 0.78). We found a close relationship between the nuisance level declared by residents and mosquito captures obtained with CO2-baited traps (Ae. caspius) and ovitraps (Ae. albopictus). An equation is presented to estimate annoyance according to dwelling characteristics and to the presence of children in the family.

Bees, honey, larvae and pollen in biomonitoring of atmospheric pollution

SummaryThe value relations of lead, chromium, nickel and cadmium as detected by automatic monitoring devices and recoderd by chemical analysis from monthly samples of the honey, pollen and larvae of honey bees are reported and discussed. The experiment was conducted at Modena in 1989 using five monitoring stations deployed around the city, each consisting of two hives. No positive correlation between the values for the biological matrices and for the abiological data was found, although there appears to be a certain latency of the pollutant in the former as compared to the latter. In most cases the plotted trends of the data, especially for lead in honey, are overlapping.

Pesticides in Ferrara Province: two years' monitoring with honey bees (1987–1988)

During the 1st year 20 strategic sites evenly distributed in this area, have been chosen. Each station consisted of two hives equipped with Gary cages to evaluate the weekly mortality. The data (presented as bee-risk maps) pointed out a situation of medium-high risk for honey bee and this was re-confirmed during the 2nd year of study with 26 stations. The most frequently detected active ingredients in these 2 years were: Dithiocarbamates (97% of 46 analyzed dead-bee samples) which are nonlethal to them, Azinphos-methyl (57%) and Dimethoate (55%) in 1987; and the same active ingredients, in the same order or importance but at different percentages (83.3%, 66.7% and 46.7% respectively) were detected on 30 dead-bee samples analyzed in 1988. These active ingredients are the most widely sold chemicals throughout the Ferrara Province.

Bio-indicators in the monitoring of environmental pollution

SummarySurveying the chemical pollution status of a given area is increasingly becoming the task of biological indicators, ie animal and plant organisms capable of providing us with the necessary data. For example, in the wake of certain contaminations, they may increase or decrease in number, vary population proportions in relation to given traits, become vectors of certain toxic molecules or heavy metals, or accumulate them in their bodies or in their «products». The advantage of bioindicators over chemical or physical detectors is their ability to supply extensive — both spatially and temporally —rather than limited and instantaneous data, thus making such information more “representative”. In many instances the bioindicator takes samples for us-a service that is undoubtedly valuable even though it must be linked to a sound knowledge of the organisms “ethogram” and biology so as to arrive at a scientifically legitimate interpretation of the data provided.