Insecticide and fungicide effect on thermal and olfactory behavior of bees and their disappearance in bees' tissues.

Plant protection products may affect the behavior of organisms which are not a target of control. The effect of Karate Zeon 050 CS (λ-Cyhalothrin -based insecticide; λ-CBI) and Amistar 250 SC (Azoxystrobin-based fungicide; ABF) was determined on Apis mellifera worker attraction towards their own colony odour, along with temperature preferences. Bees exposed to pesticides prefer the environment with the odour of their nest less often than the control group, and that insecticide-treated bees chose warmer environments than the control insects. The observed differences in the bees, especially with attraction towards their own colony, were dependent on the time of day. Chromatographic analyses indicated that λ-Cyhalothrin elimination was half that of Azoxystrobin in bee organisms, and both agents retarded each other's clearance. Mathematical modeling estimated that despite a relatively high disappearance rate, both compounds might have been bio-accumulated at relatively high level.

Assessment of risk to honey bees and honey consumers resulting from the insect exposure to captan, thiacloprid, penthiopyrad, and λ-cyhalothrin used in a commercial apple orchard.

Samples of leaves, flowers, soil, pollen, bee workers, bee brood, honey, and beeswax were collected to assess the possibility of a transfer of captan, thiacloprid, penthiopyrad, and λ-cyhalothrin from apple trees of Idared variety to honey bee (Apis mellifera) hives. Chemical analyses were performed using the Agilent 7890 Gas Chromatograph equipped with the Micro-cell Electron Capture Detector. It was found that significant amounts of penthiopyrad, the active ingredient of Fontelis 200 SC, were present in leaves, flowers, pollen, bee workers, and beeswax. Simultaneously, captan was present in the brood, worker bees, and honey samples. Significant levels of the captan residues were also detected on the soil surface. In honey samples, captan residue levels exceeded the acceptable standard, reaching 160% of its maximum residue level. However, in no case the amounts of captan, thiacloprid, penthiopyrad, and λ-cyhalothrin ingested with honey by an adult consumer exceeded the level of 0.02% of the acceptable daily intake. Despite the trace amounts of pesticide residues in honey samples collected during the field trial, bee honey consumption can be considered safe. An adult consumer can safely consume about 16 kg of honey.

The dynamics of pyrethroid residues and Cyp P450 gene expression in insects depends on the circadian clock.

A circadian clock may underlie pesticide resistance mechanisms in organisms that are very important for humans, for example, in the honey bee (Apis mellifera). Using the gas chromatography, we evaluated the daily variability in the λ-cyhalothrin degradation rate in bodies of guards and forager bees, Apis mellifera. Additionally, using the RT-qPCR method, we studied expression levels of selected cytochrome P450 genes after exposure to λ-cyhalothrin. During 48-h-tests, we exposed bees to λ-cyhalothrin at four crucial times of the day: at 04:30 a.m., 11:30 a.m., 06:30 p.m., and 11:30 p.m. The results obtained indicate that in bees the intensity of the λ-cyhalothrin degradation is the highest during first 6 h after intoxication, when it disappeared at the rate of 14.29% h-1, 11.43% h-1, 13.15% h-1, and 12.50% h-1 in bees treated at noon, sunset, midnight, and sunrise, respectively. In the later period (6-48 h of the experiment), the degradation stopped and its rate did not exceed 1.0% h-1. In the control group of bees we demonstrated that the increase in the Cyp9Q1 and Cyp9Q3 expression was the highest during the experiments started at 04:30 a.m., while the highest elevation in the Cyp9Q2 expression was observed in the group for which the experiments started at 11:30 p.m.In intoxicated honey bees, the highest increase in the Cyp9Q1 expression occurred in the group treated with the pesticide at 11:30 a.m. In the case of genes encoding Cyp9Q2 and Cyp9Q3, the highest rise in the expression took place at 06:30 p.m.The obtained results indicate that honey bees activate detoxifying mechanisms partly protecting them against the effects of hazardous substances absorbed from the environment more efficiently during foraging than at other times of the day.

The Effect of the Queen's Presence on Thermal Behavior and Locomotor Activity of Small Groups of Worker Honey Bees.

We examined effects of the queen's presence on diurnal rhythms of temperature preference (TP) and locomotor activity (LA) in worker honeybees' groups. TP and LA of six queenless and six queenright (with the queen) groups of bees, consisting of 7-8 worker bees, were recorded in a thermal gradient system for four days, under light to darkness (LD) 12:12 photoperiod. The same experiments were conducted on five virgin queens (of the same age as those in the queenright groups), which were placed individually in the gradient chambers. The single virgin queens showed signs of distress and no rhythms of TP and LA. In contrast, there were diurnal rhythms of TP and LA in both group variants with daytime activity and nighttime rest. However, the queen's presence exerted a strong calming effect, reducing LA of bees both at day- and nighttime. The nighttime minimum LA of queenright groups was five times lower than that in queenless groups. Moreover, there was a reversal of the diurnal pattern of TP in queenright groups. The results are discussed in terms of the bee colony organization as a superorganism.

Transfer of plant protection products from raspberry crops of Laszka and Seedling varieties to beehives.

Field studies were conducted to evaluate the transfer of active ingredients (AIs) of plant protection products (PPPs) to beehives. They were applied in two commodity red raspberry plantations of two varieties: Laszka (experiment 1) and Seedling (experiment 2). Samples of flowers, leaves, bees, brood, and honey were examined for the presence of chlorpyrifos, cypermethrin, difenoconazole, cyprodinil, and trifloxystrobin (experiment 1) and chlorpyrifos, boscalid, pyraclostrobin, cypermethrin, difenoconazole, and azoxystrobin (experiment 2). In experiment 1, the highest levels of trifloxystrobin were observed on the surface of flowers, (0.04 µg/flower) and for difenoconazole on the inside (0.023 µg/flower). Leaves contained only trace residues of cypermethrin and cyprodinil (0.001 µg/cm2 of leaves each) and trifloxystrobin (0.01 µg/cm2 of leaves) on the surface; inside the leaves, the highest levels of trifloxystrobin were observed (0.042 µg/cm2 of leaves). In experiment 2, boscalid was found on the surface and inside the flowers and leaves (0.063 and 0.018 µg/flower and 0.057 and 0.033 µg/cm2 of leaves, respectively). In bees, brood, and honey (experiment 1), chlorpyrifos was present in the highest quantity (7.3, 1.6, and 4.7 µg/kg, respectively). Additionally, cypermethrin and trifloxystrobin were found in bees, and trifloxystrobin was present in honey. Bees, brood, and honey from plantation 2 contained all studied AIs, with the highest levels of boscalid (28.6 µg/kg of bees, 37.0 µg/kg of brood, and 33.9 µg/kg of honey, respectively). In no case did the PPP residues in honey exceed acceptable maximum residue levels (MRLs)-from a formal and legal point of view, in terms of the used plant protection products, the analysed honey was fit for human consumption.

The transfer of active ingredients of insecticides and fungicides from an orchard to beehives.

This investigation was undertaken to determine whether active ingredients (AIs) of currently recommended plant protection products (PPPs) could be transferred to beehives from apple and pear trees. A field trial was carried out with apple trees of Ligol and Idared variety, and pear trees of Conference variety. For pest and diseases control of fungal origin, recommended PPPs were applied. Samples of flowers from the above-mentioned varieties of fruit trees, of bees, brood and honey from beehives located in their direct neighborhood were collected regularly and analyzed for the presence of lambda-cyhalothrin (an insecticide) and cyprodinil, captan, fluopyram, kresoxim-methyl, penthiopyrad and trifloxystrobin (fungicides). In samples of flowers of Ligol variety, fluopyram residues (on average 0.621 µg single flower-1) were at the highest levels, whereas in samples of pear flowers of Conference variety, and in flowers of Idared variety, captan residues (on average, respectively, 0.705 and 165.7 µg single flower-1). In samples of bees and honey, residues of five AIs were detected, and in brood six AIs, whereby in each case captan residues prevailed, respectively, up to 585.2, 51.52 and 126.5 µg kg-1 bees and honey. In the honey, significantly larger residues of captan were found out than maximum residue level (MRL) for this AI - 103.04% MRL. In the case of any AI, the daily intake did not exceed 0.002% acceptable daily intake (ADI).

Transfer of the Active Ingredients of Some Plant Protection Products from Raspberry Plants to Beehives.

Plant protection products (PPPs) have been found increasingly in the environment. They pose a huge threat to bees, contributing to honeybee colony losses and consequently to enormous economic losses. Therefore, this field investigation was designed to determine whether their active ingredients (AIs) were transferred from raspberry plants to beehives located in the immediate neighbourhood of the crop and to what extent they were transferred. Every week for 2 months, samples of soil, raspberry leaves, flowers and fruits, worker bees, honeybee brood, and honey were collected and analysed for the presence of propyzamide, chlorpyrifos, iprodione, pyraclostrobin, boscalid, cypermethrin, difenoconazole, azoxystrobin, and pyrimethanil residues. Five of these substances were found in the worker bee bodies. Chlorpyrifos, applied to only the soil through the irrigation system, also was detected in the brood. A small amount of boscalid was noted in the honey, but its residues did not exceed the maximum residue level. For chlorpyrifos, boscalid, and pyrimethanil, a positive correlation between the occurrence of PPPs in the crops and the beehives was found. Statistical methods confirmed that the application of PPPs on a raspberry plantation, as an example of nectar-secreting plants, was linked to the transfer of their AIs to beehives.

A case study on toxicological aspects of the pest and disease control in the production of the high-quality raspberry (Rubus idaeus L.).

The field studies on the residue levels of the fungicides and insecticides used in commercial raspberry (Rubus idaeus L.) plantation have been performed. Starting on the first day of harvesting (on June 19), 20 laboratory samples of fruit, 10 laboratory samples of leaves and 4 samples of soil were analyzed and the residue levels were compared to the Maximum Residue Limits (MRL) and Acceptable Daily Intakes (ADI). All analyses were carried out using extraction method and gas chromatography technique. Esfenwalerate (Sumi-alpha 050 EC) and beta-cyfluthrin (Bulldock 025 EC), the insecticides belonging to the group of synthetic pyrethroids, were not found in harvested ripe fruits, while cypermethrin residues (Cyperkill 25 EC) applied on May 24, 25 days later was still found on low levels in fruits (0.026 mg kg(-1)) and in leaves (2.58 mg kg(-1)). In turn, residues of chlorpyrifos (Dursban 480 EC), applied to the soil on May 15 against the cockchafers Melolontha melolontha and Otiorhynchus sp., were found at the level 0.004 mg kg(-1). The content of pesticides in ripe fruits depended mainly on the dose and on the time that has elapsed from the date of their application and were as follows: boscalid -0.950, pyrimethanil -0.917, pyraclostrobin -0.253 cypermethrin -0.026 and chlorpyrifos -0.004 mg kg(-1) while in leaves: boscalid -30.64, pyrimethanil -8.13, pyraclostrobin -15.82, cypermethrin -2.58 and chlorpyrifos -0.15 mg kg(-1). The highest average daily intake was in the case of boscalid, and in fruits and leaves reached the levels 0.205 and 6.63, in total 0.33% and 12.18% of ADI, respectively.

Social versus individual behaviour: a comparative approach to thermal behaviour of the honeybee (Apis mellifera L.) and the American cockroach (Periplaneta americana L.).

To study the relationship between the individual and social thermoregulatory behaviour, we used honeybee workers and American cockroaches. Single insects or groups of 10-20 individuals were placed in a temperature gradient chamber, and their thermal preference was recorded for 48 h under natural summer photoperiod. Single bees showed diurnal changes in selected ambient temperature, which culminated at 14:00 reaching 34+/-2 degrees C, and then slowly decreased, reaching a nocturnal minimum of 28+/-2 degrees C at 04:00. In contrast, the zenith of temperature selected by groups of bees (31+/-1 degrees C) was reached at 04:00 and the nadir (29+/-2 degrees C) was recorded at 14:00. Groups of bees clustered together during the night time, and dispersed during intense day time activity. Such changes were absent in groups of cockroaches. Cockroaches selected an ambient temperature of 30+/-1 degrees C both during day and night. In conclusion, there is a striking analogy in the diurnal thermal behaviour between a colony of bees and mammals. During their nychthemeral rest phase, both of them select higher temperatures than during the activity phase and, simultaneously, they reduce their overall surface area of heat loss to conserve metabolic heat. Therefore, the colony behaves as a homeothermic superorganism. In contrast, a single bee, isolated from the colony, utilizes a heterothermic strategy to save energy for a morning warm up.