Total antioxidant capacity of honeybee haemolymph in relation to age and exposure to pesticide, and comparison to antioxidant capacity of seminal plasma

Abstract

-Oxidative stress is defined as a disturbance in the balance between the production of reactive oxygen species and antioxidant defences. We measured total antioxidant capacity (TAC) in honeybee haemolymph and seminal plasma and analysed TAC of haemolymph in relation to age and exposure to pesticide. TAC of haemolymph increased with age of bees (1.18 vs 1.97 mM of (±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox) for 1-and 30-day-old bees, respectively, P ≤0.05). Exposure to imidacloprid (IMD) affected TAC of haemolymph of 1-day-old but not 30-day-old honeybees. TAC in haemolymph of 1-day-old bees was lower in treatments with the addition of 5 and 200 ppb IMD (1.57-1.46 mM of Trolox in treated bees compared with 2.37 mM of Trolox in controls; P ≤0.05). In conclusion, antioxidant protection of honeybees seems to be related to age and may be disturbed by exposure to IMD. Older bees with higher antioxidant protection seem to be less susceptible to IMD toxicity. The toxic effect of pesticide seems to be particularly dangerous in early life stages of honeybees.Apis mellifera / total antioxidant capacity / haemolymph / ageing / pesticide

Landscape and pesticide effects on honey bees: forager survival and expression of acetylcholinesterase and brain oxidative genes

“…Interestingly, expression of both the GstS3 and GstS4 genes were higher in control bees that were killed at 1-day-old (Figure 3). This finding leads to conclude that the expression of the GST genes are most probably related to the bee age, as described in (Słowińska et al 2015), rather than exposure to pesticides (Figure 3).…”

Sperm parameters of honeybee drones exposed to imidacloprid

“…The plants did not produce nectar. Exposure to IMD resulted in its transfer into honeybee bodies as described by Słowińska et al (2016). We assumed that IMD was transferred also to all individuals in hive, drones included.…”

“…We recently evaluated the relationship between the total antioxidant capacity of honeybee workers' hemolymph and IMD exposure (Słowińska et al 2016). The results revealed that antioxidant protection of honeybees is related to age and may be disturbed by exposure to IMD.…”

Osmia bicornis is rarely an adequate regulatory surrogate species. Comparing its acute sensitivity towards multiple insecticides with regulatory Apis mellifera endpoints

“…Furthermore, there are differences in the immune 214 response of young adults. In honey bees the individual detoxification capacity is 215 relatively low and increases from thereon as they age [27,28]. However, antioxidant 216 enzyme levels already rise in O. bicornis adults before eclosion which is further evidence 217 that they are more resistant than honey bees at least at this life stage [26].…”

“…24 To prevent adverse impact of pesticide applications on wild bee populations, toxic 25 effects of these substances on bee species need to be understood. However, the majority 26 of toxicity testing in laboratory and field setups has been performed using the honey 27 bee, a bred livestock species, whereas all other bee species are far less well-understood 28 in their sensitivity [10]. 29 Furthermore, the honey bee is the only pollinator species that is tested for its 30 reaction towards pesticides in the current risk assessment scheme after Regulation (EC) 31 1107/2009 [13].…”