Claudio Porrini

Standard methods for toxicology research in Apis mellifera

Summary Modern agriculture often involves the use of pesticides to protect crops. These substances are harmful to target organisms (pests and pathogens). Nevertheless, they can also damage non-target animals, such as pollinators and entomophagous arthropods. It is obvious that the undesirable side effects of pesticides on the environment should be reduced to a minimum. Western honey bees (Apis mellifera) are very important organisms from an agricultural perspective and are vulnerable to pesticide-induced impacts. They contribute actively to the pollination of cultivated crops and wild vegetation, making food production possible. Of course, since Apis mellifera occupies the same ecological niche as many other species of pollinators, the loss of honey bees caused by environmental pollutants suggests that other insects may experience a similar outcome. Because pesticides can harm honey bees and other pollinators, it is important to register pesticides that are as selective as possible. In this manuscript, we describe a selection of methods used for studying pesticide toxicity/selectiveness towards Apis mellifera. These methods may be used in risk assessment schemes and in scientific research aimed to explain acute and chronic effects of any target compound on Apis mellifera.

Influence of brood rearing temperature on honey bee development and susceptibility to poisoning by pesticides

Summary Adult honey bees (Apis mellifera) usually maintain colony brood rearing temperature between 34–35°C by thermoregulation. The brood may, however, also be subjected to suboptimal temperature. Here we investigated whether a decrease of brood rearing temperature may have effects on larval mortality, adult emergence, longevity, morphology and susceptibility to poisoning by pesticides (dimethoate). Using the in vitro rearing protocol of Aupinel (2005), we were able for the first time to control the brood temperature not only during the pupal stage but also during the larval stage. Honey bee larvae were reared in vitro at 35°C (optimal) and 33°C (suboptimal) from 12 h after hatching for 15 days. Dimethoate was tested by ingestion either on 4-day old larvae or on 7-day old adults. Our results showed that lower rearing temperature had no significant effects on larval mortality and adult emergence, but adult bee mortality was strongly affected. Moreover, adult workers emerging at 33°C were significantly more susceptible to dimethoate. Larval LD50 (48 h) was, however, 28 times higher at 33°C than at 35°C. The striking differences between larvae and adults may be explained by differential larval metabolism at 33°C and resulting slower active ingredient absorption. We conclude that adult honey bees reared at even slightly suboptimal brood temperature may be more susceptible to pesticide poisoning and be characterised by reduced longevity. Thus, low temperature brood rearing could be another stress factor for colonies.

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.

Synergistic mortality between a neonicotinoid insecticide and an ergosterol‐biosynthesis‐inhibiting fungicide in three bee species

BACKGROUND Neonicotinoid insecticides have been identified as an important factor contributing to bee diversity declines. Nonetheless, uncertainties remain about their impact under field conditions. Most studies have been conducted on Apis mellifera and tested single compounds. However, in agricultural environments, bees are often exposed to multiple pesticides. We explore the synergistic mortality between a neonicotinoid (clothianidin) and an ergosterol-biosynthesis-inhibiting fungicide (propiconazole) in three bee species (A. mellifera, Bombus terrestris, Osmia bicornis) following oral exposure in the laboratory. RESULTS We developed a new approach based on the binomial proportion test to analyse synergistic interactions. We estimated uptake of clothianidin per foraging bout in honey bees foraging on seed-coated rapeseed fields. We found significant synergistic mortality in all three bee species exposed to non-lethal doses of propiconazole and their respective LD10 of clothianidin. Significant synergism was only found at the first assessment times in A. mellifera (4 and 24 h) and B. terrestris (4 h), but persisted throughout the experiment (96 h) in O. bicornis. O. bicornis was also the most sensitive species to clothianidin. CONCLUSION Our results underscore the importance to test pesticide combinations likely to occur in agricultural environments, and to include several bee species in environmental risk assessment schemes.

Honey bee colony losses in Italy

Franco Mutinelli, Cecilia Costa, Marco Lodesani, Alessandra Baggio, Piotr Medrzycki, Giovanni Formato and Claudio Porrini Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory for Beekeeping, Viale dell’Universita’ 10, 35020 Legnaro (PD), Italy. Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Unita di Ricerca di Apicoltura e Bachicoltura (CRA-API), Via di Saliceto 80, 40128 Bologna, Italy. Istituto Zooprofilattico Sperimentale delle Regioni Lazio e Toscana, Via Appia Nuova 1411, 00178 Roma, Italy. Dipartimento di Scienze e Tecnologie Agroambientali (DiSTA), Universita di Bologna, Viale G. Fanin 42, 40127 Bologna, Italy.

The Status of Honey Bee Health in Italy: Results from the Nationwide Bee Monitoring Network

In Italy a nation-wide monitoring network was established in 2009 in response to significant honey bee colony mortality reported during 2008. The network comprised of approximately 100 apiaries located across Italy. Colonies were sampled four times per year, in order to assess the health status and to collect samples for pathogen, chemical and pollen analyses. The prevalence of Nosema ceranae ranged, on average, from 47–69% in 2009 and from 30–60% in 2010, with strong seasonal variation. Virus prevalence was higher in 2010 than in 2009. The most widespread viruses were BQCV, DWV and SBV. The most frequent pesticides in all hive contents were organophosphates and pyrethroids such as coumaphos and tau-fluvalinate. Beeswax was the most frequently contaminated hive product, with 40% of samples positive and 13% having multiple residues, while 27% of bee-bread and 12% of honey bee samples were contaminated. Colony losses in 2009/10 were on average 19%, with no major differences between regions of Italy. In 2009, the presence of DWV in autumn was positively correlated with colony losses. Similarly, hive mortality was higher in BQCV infected colonies in the first and second visits of the year. In 2010, colony losses were significantly related to the presence of pesticides in honey bees during the second sampling period. Honey bee exposure to poisons in spring could have a negative impact at the colony level, contributing to increase colony mortality during the beekeeping season. In both 2009 and 2010, colony mortality rates were positively related to the percentage of agricultural land surrounding apiaries, supporting the importance of land use for honey bee health.

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.

First isolation of Kashmir bee virus (KBV) in Italy

Antonella Cersini, Valter Bellucci, Stefano Lucci, Franco Mutinelli, Anna Granato, Claudio Porrini, Antonio Felicioli and Giovanni Formato Istituto Zooprofilattico Sperimentale delle Regioni Lazio e Toscana, Roma, Italy. ISPRA, Roma, Italy. Istituto Zooprofilattico Sperimentale delle Venezie, NRL for beekeeping, Legnaro (PD), Italy. Universita di Bologna, DISTA, Bologna, Italy. Universita di Pisa, Facolta di Medicina Veterinaria, Pisa, Italy.

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.

Biomonitoring of Bees as Bioindicators

APOIDEA SL is a technology-based company in Cordoba University, Spain. It operates environmental quality control projects through the use of monitoring stations using Apis mellifera colonies and other bees, as environmental bioindicators. In this way it attempts to improve the management, decision making and competitiveness of businesses, industries and government institutions.