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Krama T, Krams R, Munkevics M, Willow J, Popovs S, Elferts D, Dobkeviča L, Raibarte P, Rantala M, Contreras-Garduño J, Krams IA. Physiological stress and higher reproductive success in bumblebees are both associated with intensive agriculture. PeerJ 2022; 10:e12953. [PMID: 35256917 PMCID: PMC8898004 DOI: 10.7717/peerj.12953] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 01/26/2022] [Indexed: 01/11/2023] Open
Abstract
Free-living organisms face multiple stressors in their habitats, and habitat quality often affects development and life history traits. Increasing pressures of agricultural intensification have been shown to influence diversity and abundance of insect pollinators, and it may affect their elemental composition as well. We compared reproductive success, body concentration of carbon (C) and nitrogen (N), and C/N ratio, each considered as indicators of stress, in the buff-tailed bumblebee (Bombus terrestris). Bumblebee hives were placed in oilseed rape fields and semi-natural old apple orchards. Flowering season in oilseed rape fields was longer than that in apple orchards. Reproductive output was significantly higher in oilseed rape fields than in apple orchards, while the C/N ratio of queens and workers, an indicator of physiological stress, was lower in apple orchards, where bumblebees had significantly higher body N concentration. We concluded that a more productive habitat, oilseed rape fields, offers bumblebees more opportunities to increase their fitness than a more natural habitat, old apple orchards, which was achieved at the expense of physiological stress, evidenced as a significantly higher C/N ratio observed in bumblebees inhabiting oilseed rape fields.
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Affiliation(s)
| | - Ronalds Krams
- Daugavpils University, Daugavpils, Latvia,Estonian University of Life Sciences, Tartu, Estonia
| | | | | | | | | | | | | | | | | | - Indrikis A. Krams
- Daugavpils University, Daugavpils, Latvia,University of Latvia, Riga, Latvia,University of Tartu, Tartu, Estonia
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Krams IA, Krama T, Krams R, Trakimas G, Popovs S, Jõers P, Munkevics M, Elferts D, Rantala MJ, Makņa J, de Bivort BL. Serotoninergic Modulation of Phototactic Variability Underpins a Bet-Hedging Strategy in Drosophila melanogaster. Front Behav Neurosci 2021; 15:659331. [PMID: 33935664 PMCID: PMC8085305 DOI: 10.3389/fnbeh.2021.659331] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/19/2021] [Indexed: 12/04/2022] Open
Abstract
When organisms’ environmental conditions vary unpredictably in time, it can be advantageous for individuals to hedge their phenotypic bets. It has been shown that a bet-hedging strategy possibly underlies the high inter-individual diversity of phototactic choice in Drosophila melanogaster. This study shows that fruit flies from a population living in a boreal and relatively unpredictable climate have more variable variable phototactic biases than fruit flies from a more stable tropical climate, consistent with bet-hedging theory. We experimentally show that phototactic variability of D. melanogaster is regulated by the neurotransmitter serotonin (5-HT), which acts as a suppressor of the variability of phototactic choices. When fed 5-HT precursor, boreal flies exhibited lower variability, and they were insensitive to 5-HT inhibitor. The opposite pattern was seen in the tropical flies. Thus, the reduction of 5-HT in fruit flies’ brains may be the mechanistic basis of an adaptive bet-hedging strategy in a less predictable boreal climate.
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Affiliation(s)
- Indrikis A Krams
- Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia.,Department of Zoology and Animal Ecology, Faculty of Biology, University of Latvia, Riga, Latvia.,Department of Psychology, University of Tennessee, Knoxville, TN, United States
| | - Tatjana Krama
- Department of Biotechnology, Daugavpils University, Daugavpils, Latvia.,Chair of Plant Health, Estonian University of Life Sciences, Tartu, Estonia
| | - Ronalds Krams
- Department of Biotechnology, Daugavpils University, Daugavpils, Latvia.,Chair of Plant Health, Estonian University of Life Sciences, Tartu, Estonia
| | | | - Sergejs Popovs
- Department of Biotechnology, Daugavpils University, Daugavpils, Latvia
| | - Priit Jõers
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Maris Munkevics
- Department of Zoology and Animal Ecology, Faculty of Biology, University of Latvia, Riga, Latvia.,Department of Biotechnology, Daugavpils University, Daugavpils, Latvia
| | - Didzis Elferts
- Department of Botany and Ecology, Faculty of Biology, University of Latvia, Riga, Latvia
| | - Markus J Rantala
- Department of Biology, Section of Ecology, University of Turku, Turku, Finland
| | - Jānis Makņa
- Department of Artificial Intelligence and Systems Engineering, Riga Technical University, Riga, Latvia
| | - Benjamin L de Bivort
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States
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