TY - JOUR A1 - Hesselbach, Hannah A1 - Seeger, Johannes A1 - Schilcher, Felix A1 - Ankenbrand, Markus A1 - Scheiner, Ricarda T1 - Chronic exposure to the pesticide flupyradifurone can lead to premature onset of foraging in honeybees Apis mellifera JF - Journal of Applied Ecology N2 - 1.Honeybees Apis mellifera and other pollinating insects suffer from pesticides in agricultural landscapes. Flupyradifurone is the active ingredient of a novel pesticide by the name of ‘Sivanto’, introduced by Bayer AG (Crop Science Division, Monheim am Rhein, Germany). It is recommended against sucking insects and marketed as ‘harmless’ to honeybees. Flupyradifurone binds to nicotinergic acetylcholine receptors like neonicotinoids, but it has a different mode of action. So far, little is known on how sublethal flupyradifurone doses affect honeybees. 2. We chronically applied a sublethal and field‐realistic concentration of flupyradifurone to test for long‐term effects on flight behaviour using radio‐frequency identification. We examined haematoxylin/eosin‐stained brains of flupyradifurone‐treated bees to investigate possible changes in brain morphology and brain damage. 3. A field‐realistic flupyradifurone dose of approximately 1.0 μg/bee/day significantly increased mortality. Pesticide‐treated bees initiated foraging earlier than control bees. No morphological damage in the brain was observed. 4. Synthesis and applications. The early onset of foraging induced by a chronical application of flupyradifurone could be disadvantageous for honeybee colonies, reducing the period of in‐hive tasks and life expectancy of individuals. Radio‐frequency identification technology is a valuable tool for studying pesticide effects on lifetime foraging behaviour of insects. KW - radiofrequency identification KW - flight behaviour KW - flupyradifurone KW - foraging KW - histology KW - honeybee KW - insecticide KW - mortality Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-212769 VL - 57 IS - 3 ER - TY - JOUR A1 - Schilcher, Felix A1 - Hilsmann, Lioba A1 - Ankenbrand, Markus J. A1 - Krischke, Markus A1 - Mueller, Martin J. A1 - Steffan-Dewenter, Ingolf A1 - Scheiner, Ricarda T1 - Honeybees are buffered against undernourishment during larval stages JF - Frontiers in Insect Science N2 - The negative impact of juvenile undernourishment on adult behavior has been well reported for vertebrates, but relatively little is known about invertebrates. In honeybees, nutrition has long been known to affect task performance and timing of behavioral transitions. Whether and how a dietary restriction during larval development affects the task performance of adult honeybees is largely unknown. We raised honeybees in-vitro, varying the amount of a standardized diet (150 µl, 160 µl, 180 µl in total). Emerging adults were marked and inserted into established colonies. Behavioral performance of nurse bees and foragers was investigated and physiological factors known to be involved in the regulation of social organization were quantified. Surprisingly, adult honeybees raised under different feeding regimes did not differ in any of the behaviors observed. No differences were observed in physiological parameters apart from weight. Honeybees were lighter when undernourished (150 µl), while they were heavier under the overfed treatment (180 µl) compared to the control group raised under a normal diet (160 µl). These data suggest that dietary restrictions during larval development do not affect task performance or physiology in this social insect despite producing clear effects on adult weight. We speculate that possible effects of larval undernourishment might be compensated during the early period of adult life. KW - nutrition KW - juvenile hormone KW - nurse bees KW - foragers KW - triglycerides KW - undernourishment KW - task allocation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-304646 SN - 2673-8600 VL - 2 ER - TY - JOUR A1 - Schilcher, Felix A1 - Hilsmann, Lioba A1 - Rauscher, Lisa A1 - Değirmenci, Laura A1 - Krischke, Markus A1 - Krischke, Beate A1 - Ankenbrand, Markus A1 - Rutschmann, Benjamin A1 - Mueller, Martin J. A1 - Steffan-Dewenter, Ingolf A1 - Scheiner, Ricarda T1 - In vitro rearing changes social task performance and physiology in honeybees JF - Insects N2 - In vitro rearing of honeybee larvae is an established method that enables exact control and monitoring of developmental factors and allows controlled application of pesticides or pathogens. However, only a few studies have investigated how the rearing method itself affects the behavior of the resulting adult honeybees. We raised honeybees in vitro according to a standardized protocol: marking the emerging honeybees individually and inserting them into established colonies. Subsequently, we investigated the behavioral performance of nurse bees and foragers and quantified the physiological factors underlying the social organization. Adult honeybees raised in vitro differed from naturally reared honeybees in their probability of performing social tasks. Further, in vitro-reared bees foraged for a shorter duration in their life and performed fewer foraging trips. Nursing behavior appeared to be unaffected by rearing condition. Weight was also unaffected by rearing condition. Interestingly, juvenile hormone titers, which normally increase strongly around the time when a honeybee becomes a forager, were significantly lower in three- and four-week-old in vitro bees. The effects of the rearing environment on individual sucrose responsiveness and lipid levels were rather minor. These data suggest that larval rearing conditions can affect the task performance and physiology of adult bees despite equal weight, pointing to an important role of the colony environment for these factors. Our observations of behavior and metabolic pathways offer important novel insight into how the rearing environment affects adult honeybees. KW - honeybee KW - artificial rearing KW - behavior KW - in vitro KW - juvenile hormone KW - triglycerides KW - PER KW - foraging KW - nursing Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-252305 SN - 2075-4450 VL - 13 IS - 1 ER - TY - JOUR A1 - Schilcher, Felix A1 - Thamm, Markus A1 - Strube-Bloss, Martin A1 - Scheiner, Ricarda T1 - Opposing actions of octopamine and tyramine on honeybee vision JF - Biomolecules N2 - The biogenic amines octopamine and tyramine are important neurotransmitters in insects and other protostomes. They play a pivotal role in the sensory responses, learning and memory and social organisation of honeybees. Generally, octopamine and tyramine are believed to fulfil similar roles as their deuterostome counterparts epinephrine and norepinephrine. In some cases opposing functions of both amines have been observed. In this study, we examined the functions of tyramine and octopamine in honeybee responses to light. As a first step, electroretinography was used to analyse the effect of both amines on sensory sensitivity at the photoreceptor level. Here, the maximum receptor response was increased by octopamine and decreased by tyramine. As a second step, phototaxis experiments were performed to quantify the behavioural responses to light following treatment with either amine. Octopamine increased the walking speed towards different light sources while tyramine decreased it. This was independent of locomotor activity. Our results indicate that tyramine and octopamine act as functional opposites in processing responses to light. KW - biogenic amines KW - neurotransmitter KW - phototaxis KW - ERG KW - behaviour KW - modulation KW - visual system KW - octopamine KW - tyramine KW - Apis mellifera Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-246214 SN - 2218-273X VL - 11 IS - 9 ER -