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Couvillon MJ, Ohlinger BD, Bizon C, Johnson LE, McHenry LC, McMillan BE, Schürch R. A volatilized pyrethroid insecticide from a mosquito repelling device does not impact honey bee foraging and recruitment. J Insect Sci 2023; 23:11. [PMID: 38055948 PMCID: PMC10699868 DOI: 10.1093/jisesa/iead079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 08/10/2023] [Accepted: 09/08/2023] [Indexed: 12/08/2023]
Abstract
Because nontarget, beneficials, like insect pollinators, may be exposed unintentionally to insecticides, it is important to evaluate the impact of chemical controls on the behaviors performed by insect pollinators in field trials. Here we examine the impact of a portable mosquito repeller, which emits prallethrin, a pyrethroid insecticide, on honey bee foraging and recruitment using a blinded, randomized, paired, parallel group trial. We found no significant effect of the volatilized insecticide on foraging frequency (our primary outcome), waggle dance propensity, waggle dance frequency, and feeder persistency (our secondary outcomes), even though an additional deposition study confirmed that the treatment device was performing appropriately. These results may be useful to consumers that are interested in repelling mosquitos, but also concerned about potential consequences to beneficial insects, such as honey bees.
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Affiliation(s)
| | | | - Connor Bizon
- Thermacell Repellents Inc., 32 Crosby Dr., Suite #100, Bedford, MA 01730, USA
| | - Lindsay E Johnson
- Department of Entomology, 170 Drillfield Dr., Blacksburg, VA 24061, USA
| | - Laura C McHenry
- Department of Entomology, 170 Drillfield Dr., Blacksburg, VA 24061, USA
| | - Benjamin E McMillan
- Thermacell Repellents Inc., 32 Crosby Dr., Suite #100, Bedford, MA 01730, USA
| | - Roger Schürch
- Department of Entomology, 170 Drillfield Dr., Blacksburg, VA 24061, USA
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Chaccour C, Casellas A, Hammann F, Ruiz-Castillo P, Nicolas P, Montaña J, Mael M, Selvaraj P, Duthaler U, Mrema S, Kakolwa M, Lyimo I, Okumu F, Marathe A, Schürch R, Elobolobo E, Sacoor C, Saute F, Xia K, Jones C, Rist C, Maia M, Rabinovich NR. BOHEMIA: Broad One Health Endectocide-based Malaria Intervention in Africa-a phase III cluster-randomized, open-label, clinical trial to study the safety and efficacy of ivermectin mass drug administration to reduce malaria transmission in two African settings. Trials 2023; 24:128. [PMID: 36810194 PMCID: PMC9942013 DOI: 10.1186/s13063-023-07098-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 01/17/2023] [Indexed: 02/23/2023] Open
Abstract
BACKGROUND Residual malaria transmission is the result of adaptive mosquito behavior that allows malaria vectors to thrive and sustain transmission in the presence of good access to bed nets or insecticide residual spraying. These behaviors include crepuscular and outdoor feeding as well as intermittent feeding upon livestock. Ivermectin is a broadly used antiparasitic drug that kills mosquitoes feeding on a treated subject for a dose-dependent period. Mass drug administration with ivermectin has been proposed as a complementary strategy to reduce malaria transmission. METHODS A cluster randomized, parallel arm, superiority trial conducted in two settings with distinct eco-epidemiological conditions in East and Southern Africa. There will be three groups: human intervention, consisting of a dose of ivermectin (400 mcg/kg) administered monthly for 3 months to all the eligible population in the cluster (>15 kg, non-pregnant and no medical contraindication); human and livestock intervention, consisting human treatment as above plus treatment of livestock in the area with a single dose of injectable ivermectin (200 mcg/kg) monthly for 3 months; and controls, consisting of a dose of albendazole (400 mg) monthly for 3 months. The main outcome measure will be malaria incidence in a cohort of children under five living in the core of each cluster followed prospectively with monthly RDTs DISCUSSION: The second site for the implementation of this protocol has changed from Tanzania to Kenya. This summary presents the Mozambique-specific protocol while the updated master protocol and the adapted Kenya-specific protocol undergo national approval in Kenya. BOHEMIA will be the first large-scale trial evaluating the impact of ivermectin-only mass drug administration to humans or humans and cattle on local malaria transmission TRIAL REGISTRATION: ClinicalTrials.gov NCT04966702 . Registered on July 19, 2021. Pan African Clinical Trials Registry PACTR202106695877303.
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Affiliation(s)
- Carlos Chaccour
- ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain. .,Universidda de Navarra, Pamplona, Spain. .,Centro de Investigación Biomédica en Red de Enfermedades Infecciosas, Madrid, Spain.
| | - Aina Casellas
- grid.434607.20000 0004 1763 3517ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain
| | - Felix Hammann
- grid.411656.10000 0004 0479 0855University Hospital of Bern, Inselspital, Bern, Switzerland
| | - Paula Ruiz-Castillo
- grid.434607.20000 0004 1763 3517ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain
| | - Patricia Nicolas
- grid.434607.20000 0004 1763 3517ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain
| | - Julia Montaña
- grid.434607.20000 0004 1763 3517ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain
| | - Mary Mael
- grid.434607.20000 0004 1763 3517ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain
| | - Prashant Selvaraj
- grid.418309.70000 0000 8990 8592Bill and Melinda Gates Foundation, Seattle, USA
| | - Urs Duthaler
- grid.6612.30000 0004 1937 0642University Basel, Basel, Switzerland
| | - Sigilbert Mrema
- grid.414543.30000 0000 9144 642XIfakara Health Institute, Ifakara, Tanzania
| | - Mwaka Kakolwa
- grid.414543.30000 0000 9144 642XIfakara Health Institute, Ifakara, Tanzania
| | - Issa Lyimo
- grid.414543.30000 0000 9144 642XIfakara Health Institute, Ifakara, Tanzania
| | - Fredros Okumu
- grid.414543.30000 0000 9144 642XIfakara Health Institute, Ifakara, Tanzania
| | - Achla Marathe
- grid.27755.320000 0000 9136 933XUniversity of Virginia, Charlottesville, USA
| | - Roger Schürch
- grid.438526.e0000 0001 0694 4940Virginia Polytechnic Institute and State University, Blacksburg, USA
| | - Eldo Elobolobo
- grid.452366.00000 0000 9638 9567Centro de Investigação em Saúde de Manhiça, Manhica, Mozambique
| | - Charfudin Sacoor
- grid.452366.00000 0000 9638 9567Centro de Investigação em Saúde de Manhiça, Manhica, Mozambique
| | - Francisco Saute
- grid.452366.00000 0000 9638 9567Centro de Investigação em Saúde de Manhiça, Manhica, Mozambique
| | - Kang Xia
- grid.438526.e0000 0001 0694 4940Virginia Polytechnic Institute and State University, Blacksburg, USA
| | - Caroline Jones
- grid.33058.3d0000 0001 0155 5938KEMRI Wellcome Trust Research Programme, Kilifi, Kenya
| | - Cassidy Rist
- grid.438526.e0000 0001 0694 4940Virginia Polytechnic Institute and State University, Blacksburg, USA
| | - Marta Maia
- grid.33058.3d0000 0001 0155 5938KEMRI Wellcome Trust Research Programme, Kilifi, Kenya
| | - N. Regina Rabinovich
- grid.434607.20000 0004 1763 3517ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain ,grid.38142.3c000000041936754XTH Chan Harvard School of Public Health, Boston, USA
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Steele TN, Schürch R, Ohlinger BD, Couvillon MJ. Apple orchards feed honey bees during, but even more so after, bloom. Ecosphere 2022. [DOI: 10.1002/ecs2.4228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
| | - Roger Schürch
- Department of Entomology Virginia Tech Blacksburg Virginia USA
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Abstract
Much like human consumers, honeybees adjust their behaviours based on resources' supply and demand. For both, interactions occur in fluctuating conditions. Honeybees weigh the cost of flight against the benefit of nectar and pollen, which are nutritionally distinct resources that serve different purposes: bees collect nectar continuously to build large honey stores for overwintering, but they collect pollen intermittently to build modest stores for brood production periods. Therefore, nectar foraging can be considered a supply-driven process, whereas pollen foraging is demand-driven. Here we compared the foraging distances, communicated by waggle dances and serving as a proxy for cost, for nectar and pollen in three ecologically distinct landscapes in Virginia. We found that honeybees foraged for nectar at distances 14% further than for pollen across all three sites (n = 6224 dances, p < 0.001). Specific temporal dynamics reveal that monthly nectar foraging occurs at greater distances compared with pollen foraging 85% of the time. Our results strongly suggest that honeybee foraging cost dynamics are consistent with nectar supply-driven and pollen demand-driven processes.
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Affiliation(s)
- Bradley D Ohlinger
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Roger Schürch
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Mary R Silliman
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Taylor N Steele
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Margaret J Couvillon
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
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Silliman MR, Schürch R, Malone S, Taylor SV, Couvillon MJ. Row crop fields provide mid‐summer forage for honey bees. Ecol Evol 2022; 12:e8979. [PMID: 35784068 PMCID: PMC9170536 DOI: 10.1002/ece3.8979] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 04/19/2022] [Indexed: 11/15/2022] Open
Abstract
Honey bees provide invaluable economic and ecological services while simultaneously facing stressors that may compromise their health. For example, agricultural landscapes, such as a row crop system, are necessary for our food production, but they may cause poor nutrition in bees from a lack of available nectar and pollen. Here, we investigated the foraging dynamics of honey bees in a row crop environment. We decoded, mapped, and analyzed 3459 waggle dances, which communicate the location of where bees collected food, for two full foraging seasons (April–October, 2018–2019). We found that bees recruited nestmates mostly locally (<2 km) throughout the season. The shortest communicated median distances (0.474 and 0.310 km), indicating abundant food availability, occurred in July in both years, which was when our row crops were in full bloom. We determined, by plotting and analyzing the communicated locations, that almost half of the mid‐summer recruitment was to row crops, with 37% (2018) and 50% (2019) of honey bee dances indicating these fields. Peanut was the most attractive in July, followed by corn and cotton but not soybean. Overall, row crop fields are indicated by a surprisingly large proportion of recruitment dances, suggesting that similar agricultural landscapes may also provide mid‐summer foraging opportunities for honey bees.
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Affiliation(s)
- Mary R. Silliman
- Department of Entomology (MC0319) Virginia Tech Blacksburg Virginia USA
| | - Roger Schürch
- Department of Entomology (MC0319) Virginia Tech Blacksburg Virginia USA
| | - Sean Malone
- Tidewater Agricultural Research and Extension Center Virginia Tech Suffolk Virginia USA
| | - Sally V. Taylor
- Tidewater Agricultural Research and Extension Center Virginia Tech Suffolk Virginia USA
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Reichenbach S, Jüni P, Hincapié CA, Schneider C, Meli DN, Schürch R, Streit S, Lucas C, Mebes C, Rutjes AWS, da Costa BR. Effect of transcutaneous electrical nerve stimulation (TENS) on knee pain and physical function in patients with symptomatic knee osteoarthritis: the ETRELKA randomized clinical trial. Osteoarthritis Cartilage 2022; 30:426-435. [PMID: 34826572 DOI: 10.1016/j.joca.2021.10.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 09/30/2021] [Accepted: 10/27/2021] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine the effectiveness of TENS at relieving pain and improving physical function as compared to placebo TENS, and to determine its safety, in patients with knee osteoarthritis. METHODS Multi-centre, parallel, 1:1 randomized, double-blind, placebo-controlled clinical trial conducted in six outpatient clinics in Switzerland. We included 220 participants with knee osteoarthritis recruited between October 15, 2012, and October 15, 2014. Patients were randomized to 3 weeks of treatment with TENS (n = 108) or placebo TENS (n = 112). Our pre-specified primary endpoint was knee pain at the end of 3-weeks treatment assessed with the WOMAC pain subscale. Secondary outcome measures included WOMAC physical function subscale and safety outcomes. RESULTS There was no difference between TENS and placebo TENS in WOMAC pain at the end of treatment (mean difference -0.06; 95%CI -0.41 to 0.29; P = 0.74), nor throughout the trial duration (P = 0.98). Subgroup analyses did not indicate an interaction between patient/treatment characteristics and treatment effect on WOMAC pain at the end of treatment (P-interaction ≥0.22). The occurrence of adverse events was similar across groups, with 10.4% and 10.6% of patients reporting events in the TENS and placebo TENS groups, respectively (P = 0.95). No relevant differences were observed in secondary outcomes. CONCLUSIONS TENS does not improve knee osteoarthritis pain when compared to placebo TENS. Therapists should consider other potentially more effective treatment modalities to decrease knee osteoarthritis pain and facilitate strengthening and aerobic exercise. Our findings are conclusive and further trials comparing TENS and placebo TENS in this patient population are not necessary.
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Affiliation(s)
- S Reichenbach
- Institute for Social and Preventive Medicine (ISPM), University of Bern, Switzerland; Department of Rheumatology and Immunology, Bern University Hospital, Switzerland
| | - Peter Jüni
- Institute of Health Policy, Management, and Evaluation, Department of Medicine, University of Toronto, Toronto, Canada; Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Canada
| | - C A Hincapié
- Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Canada; Department of Chiropractic Medicine, Faculty of Medicine, University of Zurich and Balgrist University Hospital, Zurich, Switzerland; Epidemiology, Biostatistics and Prevention Institute (EBPI), University of Zurich, Zurich, Switzerland
| | - C Schneider
- Institute for Social and Preventive Medicine (ISPM), University of Bern, Switzerland; Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - D N Meli
- General Practice, Huttwil, Switzerland
| | - R Schürch
- Institute for Social and Preventive Medicine (ISPM), University of Bern, Switzerland; CTU Bern, University of Bern, Switzerland; Department of Entomology, Virginia Tech Polytechnic Institute & State University, Blacksburg, USA
| | - S Streit
- Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland
| | - C Lucas
- Department of Clinical Epidemiology, Biostatistics and Bioinformatics, University of Amsterdam, Faculty of Medicine (AMC), Amsterdam, the Netherlands
| | - C Mebes
- Physio Postmarkt AG, Grenchen, Switzerland
| | - A W S Rutjes
- Institute for Social and Preventive Medicine (ISPM), University of Bern, Switzerland
| | - B R da Costa
- Institute of Health Policy, Management, and Evaluation, Department of Medicine, University of Toronto, Toronto, Canada; Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Canada; Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland.
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7
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Ohlinger BD, Schürch R, Durzi S, Kietzman PM, Silliman MR, Couvillon MJ. Honey Bees (Hymenoptera: Apidae) Decrease Foraging But Not Recruitment After Neonicotinoid Exposure. J Insect Sci 2022; 22:6523142. [PMID: 35137133 PMCID: PMC8826047 DOI: 10.1093/jisesa/ieab095] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Indexed: 05/24/2023]
Abstract
Honey bees (Linnaeus, Hymenoptera: Apidae) are widely used as commercial pollinators and commonly forage in agricultural and urban landscapes containing neonicotinoid-treated plants. Previous research has demonstrated that honey bees display adverse behavioral and cognitive effects after treatment with sublethal doses of neonicotinoids. In laboratory studies, honey bees simultaneously increase their proportional intake of neonicotinoid-treated solutions and decrease their total solution consumption to some concentrations of certain neonicotinoids. These findings suggest that neonicotinoids might elicit a suboptimal response in honey bees, in which they forage preferentially on foods containing pesticides, effectively increasing their exposure, while also decreasing their total food intake; however, behavioral responses in semifield and field conditions are less understood. Here we conducted a feeder experiment with freely flying bees to determine the effects of a sublethal, field-realistic concentration of imidacloprid (IMD) on the foraging and recruitment behaviors of honey bees visiting either a control feeder containing a sucrose solution or a treatment feeder containing the same sucrose solution with IMD. We report that IMD-treated honey bees foraged less frequently (-28%) and persistently (-66%) than control foragers. Recruitment behaviors (dance frequency and dance propensity) also decreased with IMD, but nonsignificantly. Our results suggest that neonicotinoids inhibit honey bee foraging, which could potentially decrease food intake and adversely affect colony health.
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Affiliation(s)
- Bradley D Ohlinger
- Department of Entomology, Virginia Tech, 216 Price Hall, 170 Drillfield Drive, Blacksburg, VA 24061, USA
| | - Roger Schürch
- Department of Entomology, Virginia Tech, 216 Price Hall, 170 Drillfield Drive, Blacksburg, VA 24061, USA
| | - Sharif Durzi
- Department of Entomology, Virginia Tech, 216 Price Hall, 170 Drillfield Drive, Blacksburg, VA 24061, USA
- Pasadena Office Natural Resources Department, SWCA Environmental Consultants, 51 W Dayton St, Pasadena, CA 91105, USA
| | - Parry M Kietzman
- Department of Entomology, Virginia Tech, 216 Price Hall, 170 Drillfield Drive, Blacksburg, VA 24061, USA
- School of Plant and Environmental Sciences, Virginia Tech, 328 Smyth Hall, 185 Ag Quad Lane, Blacksburg, VA 24061, USA
| | - Mary R Silliman
- Department of Entomology, Virginia Tech, 216 Price Hall, 170 Drillfield Drive, Blacksburg, VA 24061, USA
| | - Margaret J Couvillon
- Department of Entomology, Virginia Tech, 216 Price Hall, 170 Drillfield Drive, Blacksburg, VA 24061, USA
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Whitlow AM, Schürch R, Mullins D, Eastwood G. The Influence of Southwestern Virginia Environmental Conditions on the Potential Ability of Haemaphysalis longicornis, Amblyomma americanum, and Amblyomma maculatum to Overwinter in the Region. Insects 2021; 12:insects12111000. [PMID: 34821800 PMCID: PMC8622198 DOI: 10.3390/insects12111000] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 10/28/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary A tick’s ability to survive in cold, harsh winter conditions is influenced by numerous factors including the tick species, the variability in temperature, and the suitability of the overwintering habitat (containing insulation to retain heat). We investigated the influence of elevation and insulation coverage on the survivability of three newly invading ticks, Amblyomma americanum, Amblyomma maculatum, and Haemaphysalis longicornis and one native tick species already established in southwestern Virginia, Dermacentor variabilis. For the invasive species, we found that life stage was the only determining factor in survival for Haemaphysalis longicornis and Amblyomma americanum, whereas, Amblyomma maculatum survival was largely influenced by insulation coverage. Dermacentor variabilis survivability was not affected by elevation or insulation coverage in this study. Abstract Ticks are susceptible to environmental conditions and, to ensure survival during winter conditions, they adopt a wide variety of physiological and behavioral adaptations including utilization of a suitable niche with insulation (e.g., leaf coverage). To investigate the potential overwintering survival of three tick populations emerging within Appalachian Virginia (Haemaphysalis longicornis, Amblyomma americanum, and Amblyomma maculatum), both a laboratory experiment assessing super-cooling points and a two-factor (elevation and insulation coverage) field experiment assessing overwintering survivability were conducted across a natural southwestern Virginian winter (2020–2021). Dermacentor variabilis adults were included in this study as an example of a well-established species in this region known to overwinter in these conditions. Our study indicated that A. americanum and H. longicornis wintering tolerance is based on life stage rather than external factors such as insulation (e.g., leaf litter) and elevation. Amblyomma maculatum was more likely to survive without insulation. The ability to withstand the extreme temperatures of new regions is a key factor determining the survivability of novel tick species and is useful in assessing the invasion potential of arthropod vectors.
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Affiliation(s)
- Amanda Marie Whitlow
- Department of Entomology, Virginia Tech Polytechnic Institute & State University, Blacksburg, VA 24061, USA; (A.M.W.); (R.S.); (D.M.)
| | - Roger Schürch
- Department of Entomology, Virginia Tech Polytechnic Institute & State University, Blacksburg, VA 24061, USA; (A.M.W.); (R.S.); (D.M.)
| | - Donald Mullins
- Department of Entomology, Virginia Tech Polytechnic Institute & State University, Blacksburg, VA 24061, USA; (A.M.W.); (R.S.); (D.M.)
| | - Gillian Eastwood
- Department of Entomology, Virginia Tech Polytechnic Institute & State University, Blacksburg, VA 24061, USA; (A.M.W.); (R.S.); (D.M.)
- Global Change Center, Virginia Tech Polytechnic Institute & State University, Blacksburg, VA 24061, USA
- Correspondence:
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Carr-Markell MK, Demler CM, Couvillon MJ, Schürch R, Spivak M. Correction: Do honey bee (Apis mellifera) foragers recruit their nestmates to native forbs in reconstructed prairie habitats? PLoS One 2021; 16:e0259603. [PMID: 34724003 PMCID: PMC8559934 DOI: 10.1371/journal.pone.0259603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Affiliation(s)
- Ash E. Samuelson
- Department of Biological Sciences Royal Holloway University of London Egham UK
| | - Roger Schürch
- Department of Entomology Virginia Tech Blacksburg VA USA
| | - Ellouise Leadbeater
- Department of Biological Sciences Royal Holloway University of London Egham UK
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Bryant TB, Dorman SJ, Reisig DD, Dillard D, Schürch R, Taylor SV. Reevaluating the Economic Injury Level for Brown Stink Bug (Hemiptera: Pentatomidae) at Various Growth Stages of Maize. J Econ Entomol 2020; 113:2250-2258. [PMID: 32840569 DOI: 10.1093/jee/toaa173] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Indexed: 06/11/2023]
Abstract
Economic yield loss and reduction in grain quality from brown stink bug, Euschistus servus (Say), feeding injury in early and late stages of maize, Zea mays (Poales: Poaceae, Linnaeus), development was assessed in Virginia and North Carolina in 2018 and 2019. Varying levels of stink bug infestations were introduced to seedling maize (V2-early stage), and a range of late-stages of maize, including 1) the last stage of vegetative development (V12/V14), 2) prior to tasseling, 3) at tasseling (VT), and 4) across all tested late growth stages. Euschistus servus infestation levels included 33, 67, and 100% of maize seedlings, and 25, 50, 100, and 200% of plants during later stages. Infestations were maintained on seedling maize for 7 d, and 8 or 16 d in reproductive stages. Infestation level in seedling maize had an impact on grain yield. Infestation level and growth stage both had an impact on grain yield in reproductive maize. The percentage of discolored kernels was also affected by infestation level, but not growth stage. Regression analysis between grain yield and infestation level indicated that the average economic injury level is 7% in seedling maize (7 bugs/100 plants) and 12% (12 bugs/100 plants) from the last vegetative stages (V12/V14) through pollination (VT). The economic injury level in the late vegetative stages is only applicable when infestations are present for an extended period of time (16 d), emphasizing the need for continued scouting of maize throughout the season to make informed management decisions.
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Affiliation(s)
- Tim B Bryant
- Virginia Tech, Tidewater Agricultural Research and Extension Center, Suffolk, VA
- Clemson University, PeeDee Research and Education Center, Florence, SC
| | - Seth J Dorman
- Virginia Tech, Tidewater Agricultural Research and Extension Center, Suffolk, VA
| | - Dominic D Reisig
- North Carolina State University, Vernon James Research and Extension Center, Plymouth, NC
| | - DeShae Dillard
- North Carolina State University, Vernon James Research and Extension Center, Plymouth, NC
| | - Roger Schürch
- Virginia Tech, Department of Entomology, Blacksburg, VA
| | - Sally V Taylor
- Virginia Tech, Tidewater Agricultural Research and Extension Center, Suffolk, VA
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Walkner S, Schürch R, Glaab R. Penetrierende Kniegelenkverletzung. Arthroskopie 2020. [DOI: 10.1007/s00142-019-00335-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Carr-Markell MK, Demler CM, Couvillon MJ, Schürch R, Spivak M. Do honey bee (Apis mellifera) foragers recruit their nestmates to native forbs in reconstructed prairie habitats? PLoS One 2020; 15:e0228169. [PMID: 32049993 PMCID: PMC7015315 DOI: 10.1371/journal.pone.0228169] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/08/2020] [Indexed: 02/02/2023] Open
Abstract
Honey bee (Apis mellifera) colonies are valued for the pollination services that they provide. However, colony mortality has increased to unsustainable levels in some countries, including the United States. Landscape conversion to monocrop agriculture likely plays a role in this increased mortality by decreasing the food sources available to honey bees. Many land owners and organizations in the Upper Midwest region of the United States would like to restore/reconstruct native prairie habitats. With increasing public awareness of high bee mortality, many landowners and beekeepers have wondered whether these restored prairies could significantly improve honey bee colony nutrition. Conveniently, honey bees have a unique communication signal called a waggle dance, which indicates the locations of the flower patches that foragers perceive as highly profitable food sources. We used these communication signals to answer two main questions: First, is there any part of the season in which the foraging force of a honey bee colony will devote a large proportion of its recruitment efforts (waggle dances) to flower patches within prairies? Second, will honey bee foragers advertise specific taxa of native prairie flowers as profitable pollen sources? We decoded 1528 waggle dances in colonies located near two large, reconstructed prairies. We also collected pollen loads from a subset of waggle-dancing bees, which we then analyzed to determine the flower taxon advertised. Most dances advertised flower patches outside of reconstructed prairies, but the proportion of dances advertising nectar sources within prairies increased significantly in the late summer/fall at one site. Honey bees advertised seven native prairie taxa as profitable pollen sources, although the three most commonly advertised pollen taxa were non-native. Our results suggest that including certain native prairie flower taxa in reconstructed prairies may increase the chances that colonies will use those prairies as major food sources during the period of greatest colony growth and honey production.
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Affiliation(s)
- Morgan K. Carr-Markell
- Department of Entomology, University of Minnesota, Falcon Heights, Minnesota, United States of America
- * E-mail:
| | - Cora M. Demler
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Margaret J. Couvillon
- Department of Entomology, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Roger Schürch
- Department of Entomology, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Marla Spivak
- Department of Entomology, University of Minnesota, Falcon Heights, Minnesota, United States of America
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Keel I, Schürch R, Weiss J, Zwahlen M, Immer FF. Is there an association between consent rates in Swiss hospitals and critical care staffs' attitudes towards organ donation, their knowledge and confidence in the donation process? PLoS One 2019; 14:e0211614. [PMID: 30735508 PMCID: PMC6368376 DOI: 10.1371/journal.pone.0211614] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 01/17/2019] [Indexed: 11/19/2022] Open
Abstract
This study investigated the critical care staff’s attitude, knowledge and involvement with donation, skills and confidence with donation-related tasks and their association with consent rates at the hospital level. In 2015, we conducted a cross-sectional survey among critical care staff of hospitals involved in organ donation using an anonymous online questionnaire with a response rate of 56.4% (n = 2799). The hospital level consent rate was obtained from the Swiss Monitoring of Potential Donors database (2013–2015). For each hospital, we calculated a mean score for each predictor of interest of the Hospital Attitude Survey and investigated the association with hospital consent rates with generalized linear mixed-effect models. In univariable analysis, one score point increase in doctors' confidence resulted in a 66% (95% CI: 45%–80%) reduction in the odds to consent, and one score point increase in nurses' attitudes resulted in a 223% (95% CI: 84%–472%) increase in the odds to consent. After simultaneously adjusting for all major predictors found in the crude models, only levels of education of medical and nursing staff remained as significant predictors for hospital consent rates. In Switzerland, efforts are needed to increase consent rates for organ donation and should concentrate on continuous support as well as specific training of the hospital staff involved in the donation process.
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Affiliation(s)
- Isabelle Keel
- Swisstransplant, the Swiss National Foundation for Organ Donation and Transplantation, Bern, Switzerland
| | - Roger Schürch
- CTU Bern, Department of Clinical Research and Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
| | - Julius Weiss
- Swisstransplant, the Swiss National Foundation for Organ Donation and Transplantation, Bern, Switzerland
| | - Marcel Zwahlen
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
| | - Franz F. Immer
- Swisstransplant, the Swiss National Foundation for Organ Donation and Transplantation, Bern, Switzerland
- * E-mail:
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15
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Corby-Harris V, Bowsher JH, Carr-Markell M, Carroll MJ, Centrella M, Cook SC, Couvillon M, DeGrandi-Hoffman G, Dolezal A, Jones JC, Mogren CL, Otto CRV, Lau P, Rangel J, Schürch R, St. Clair A. Emerging Themes from the ESA Symposium Entitled “Pollinator Nutrition: Lessons from Bees at Individual to Landscape Levels”. ACTA ACUST UNITED AC 2018. [DOI: 10.1080/0005772x.2018.1535951] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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16
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Schubert M, Schürch R, Boettger S, Garcia Nuñez D, Schwarz U, Bettex D, Jenewein J, Bogdanovic J, Staehli ML, Spirig R, Rudiger A. A hospital-wide evaluation of delirium prevalence and outcomes in acute care patients - a cohort study. BMC Health Serv Res 2018; 18:550. [PMID: 30005646 PMCID: PMC6045819 DOI: 10.1186/s12913-018-3345-x] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [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: 07/09/2017] [Accepted: 07/01/2018] [Indexed: 12/15/2022] Open
Abstract
Background Delirium is a well-known complication in cardiac surgery and intensive care unit (ICU) patients. However, in many other settings its prevalence and clinical consequences are understudied. The aims of this study were: (1) To assess delirium prevalence in a large, diverse cohort of acute care patients classified as either at risk or not at risk for delirium; (2) To compare these two groups according to defined indicators; and (3) To compare delirious with non-delirious patients regarding hospital mortality, ICU and hospital length of stay, nursing hours and cost per case. Methods This cohort study was performed in a Swiss university hospital following implementation of a delirium management guideline. After excluding patients aged < 18 years or with a length of stay (LOS) < 1 day, 29′278 patients hospitalized in the study hospital in 2014 were included. Delirium period prevalence was calculated based on a Delirium Observation Scale (DOS) score ≥ 3 and / or Intensive Care Delirium Screening Checklist (ICDSC) scores ≥4. Results Of 10′906 patients admitted, DOS / ICDSC scores indicated delirium in 28.4%. Delirium was most prevalent (36.2–40.5%) in cardiac surgery, neurosurgery, trauma, radiotherapy and neurology patients. It was also common in geriatrics, internal medicine, visceral surgery, reconstructive plastic surgery and cranio-maxillo-facial surgery patients (prevalence 21.6–28.6%). In the unadjusted and adjusted models, delirious patients had a significantly higher risk of inpatient mortality, stayed significantly longer in the ICU and hospital, needed significantly more nursing hours and generated significantly higher costs per case. For the seven most common ICD-10 diagnoses, each diagnostic group’s delirious patients had worse outcomes compared to those with no delirium. Conclusions The results indicate a high number of patients at risk for delirium, with high delirium prevalence across all patient groups. Delirious patients showed significantly worse clinical outcomes and generated higher costs. Subgroup analyses highlighted striking variations in delirium period-prevalence across patient groups. Due to the high prevalence of delirium in patients treated in care centers for radiotherapy, visceral surgery, reconstructive plastic surgery, cranio-maxillofacial surgery and oral surgery, it is recommended to expand the current focus of delirium management to these patient groups. Electronic supplementary material The online version of this article (10.1186/s12913-018-3345-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maria Schubert
- Nursing Science, Faculty of Medicine, Department of Public Health, University of Basel, Bernoullistr. 28, 4056, Basel, Switzerland. .,Directorate of Nursing/MTT, Insel Gruppe, University Hospital Inselspital, Bern, Freiburgstr. 44a, 3010, Bern, Switzerland. .,School of Health Professions, Institute of Nursing, Zurich University of Applied Science, Technikumstr. 81, P.O. Box, 8401, Winterthur, Switzerland.
| | - Roger Schürch
- Clinical Trial Unit, Institute of Social and Preventive Medicine, University of Bern, Finkenhubelweg 11, 3012, Bern, Switzerland.,Virginia Tech, Department of Entomology (MC0319), 170 Drillfield Drive, Blacksburg, VA, 24061, USA
| | - Soenke Boettger
- Department of Psychiatry and Psychotherapy, University Hospital Zurich, Raemistr. 100, 8091, Zurich, Switzerland
| | - David Garcia Nuñez
- Department of Psychiatry and Psychotherapy, University Hospital Zurich, Raemistr. 100, 8091, Zurich, Switzerland.,Center for Gender Variance, University Hospital Basel, Spitalstrasse 21, 4056, Basel, Switzerland
| | - Urs Schwarz
- Division of Neurology, University Hospital Zurich, Raemistr. 100, 8091, Zurich, Switzerland
| | - Dominique Bettex
- Institute of Anesthesiology, University of Zurich and University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland
| | - Josef Jenewein
- Department of Psychiatry and Psychotherapy, University Hospital Zurich, Raemistr. 100, 8091, Zurich, Switzerland
| | - Jasmina Bogdanovic
- Nursing Science, Faculty of Medicine, Department of Public Health, University of Basel, Bernoullistr. 28, 4056, Basel, Switzerland
| | - Marina Lynne Staehli
- Nursing Department, Balgrist University Hospital, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Rebecca Spirig
- Directorate of Nursing/MTT, Insel Gruppe, University Hospital Inselspital, Bern, Freiburgstr. 44a, 3010, Bern, Switzerland.,Nursing and Allied Health Care Professions Office, University Hospital Zurich, Raemistr. 100, 8091, Zurich, Switzerland
| | - Alain Rudiger
- Institute of Anesthesiology, University of Zurich and University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland
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17
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Merz TM, Pereira AJ, Schürch R, Schefold JC, Jakob SM, Takala J, Djafarzadeh S. Mitochondrial function of immune cells in septic shock: A prospective observational cohort study. PLoS One 2017; 12:e0178946. [PMID: 28591158 PMCID: PMC5462395 DOI: 10.1371/journal.pone.0178946] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 05/22/2017] [Indexed: 12/14/2022] Open
Abstract
Background Reduced cellular ATP synthesis due to impaired mitochondrial function of immune cells may be a factor influencing the immune response in septic shock. We investigate changes in mitochondrial function and bioenergetics of human monocytes and lymphocyte subsets. Methods Thirty patients with septic shock were studied at ICU admission, after 24 and 48 hours, and after resolution of shock. Enzymatic activities of citrate synthase and mitochondrial complexes I, IV, and ATP synthase and ATP content of monocytes, T-cells and B-cells and pro-inflammatory (IL-1β and IL-6) and anti-inflammatory (IL-10) cytokine plasma concentrations were compared to samples from 20 healthy volunteers. Results Large variations in mitochondrial enzymatic activities of immune cells of septic patients were detected. In monocytes, maximum levels of citrate synthase activity in sepsis were significantly lower when compared to controls (p = 0.021). Maximum relative enzymatic activity (ratio relative to citrate synthase activity) of complex I (p<0.001), complex IV (p = 0.017) and ATP synthase (p<0.001) were significantly higher. In T-cells, maximum levels of citrate synthase (p = 0.583) and relative complex IV (p = 0.602) activity did not differ between patients and controls, whereas levels of relative complex I (p = 0.006) and ATP synthase (p = 0.032) were significantly higher in septic patients. In B-cells of patients, maximum levels of citrate synthase activity (p = 0.004) and relative complex I (p<0.001) were significantly higher, and mean levels of relative complex IV (p = 0.042) lower than the control values, whereas relative ATP synthase activity did not differ (p = 1.0). No significant difference in cellular ATP content was detected in any cell line (p = 0.142–0.519). No significant correlations between specific cytokines and parameters of mitochondrial enzymatic activities or ATP content were observed. Conclusions Significant changes of mitochondrial enzymatic activities occur in human peripheral blood immune cells in septic shock when compared to healthy controls. Assessed sub-types of immune cells showed differing patterns of regulation. Total ATP-content of human immune cells did not differ between patients in septic shock and healthy volunteers.
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Affiliation(s)
- Tobias M. Merz
- Department of Intensive Care Medicine, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland
- * E-mail:
| | - Adriano J. Pereira
- Department of Intensive Care Medicine, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland
| | - Roger Schürch
- Division of Statistics, Clinical Trials Unit, Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - Joerg C. Schefold
- Department of Intensive Care Medicine, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland
| | - Stephan M. Jakob
- Department of Intensive Care Medicine, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland
| | - Jukka Takala
- Department of Intensive Care Medicine, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland
| | - Siamak Djafarzadeh
- Department of Intensive Care Medicine, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland
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18
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von Wolff M, Kohl Schwartz A, Stute P, Fäh M, Otti G, Schürch R, Rohner S. Follicular flushing in natural cycle IVF does not affect the luteal phase - a prospective controlled study. Reprod Biomed Online 2017; 35:37-41. [PMID: 28483339 DOI: 10.1016/j.rbmo.2017.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 11/24/2022]
Abstract
In contrast to multifollicular IVF, follicular flushing seems to increase the efficacy of monofollicular IVF treatments such as natural cycle IVF (NC-IVF). However, because follicular flushing causes loss of granulosa cells, it might negatively affect luteal phase length and endocrine function of the luteal body. A prospective cohort Phase II study was performed in 24 women undergoing NC-IVF. Women underwent a reference cycle with human chorionic gonadotrophin-induced ovulation without follicle aspiration and analysis of the length of the luteal phase and luteal concentrations of progesterone and oestradiol. In addition, they underwent a NC-IVF cycle which was performed identically but follicles were aspirated and flushed three times. The luteal phase was shorter in 29.2%, equal in 16.7% and longer in 50.0% of cases following flushing of the follicles. Overall, neither difference in luteal phase length was significant [median duration (interquartile range) in reference cycle: 13 (12; 14.5), IVF (flushing) cycle: 14 (12.5; 14.5), median difference (95% CI): 0.5 (-0.5 to 1.5)] nor median progesterone and oestradiol concentrations. In conclusion, follicular flushing in NC-IVF affects neither the length of the luteal phase nor the luteal phase concentrations of progesterone and oestradiol, questioning the need for luteal phase supplementation.
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Affiliation(s)
- M von Wolff
- University Women's Hospital, Division of Gynaecological Endocrinology and Reproductive Medicine, Berne, Switzerland.
| | - A Kohl Schwartz
- University Women's Hospital, Division of Gynaecological Endocrinology and Reproductive Medicine, Berne, Switzerland
| | - P Stute
- University Women's Hospital, Division of Gynaecological Endocrinology and Reproductive Medicine, Berne, Switzerland
| | - M Fäh
- University Women's Hospital, Division of Gynaecological Endocrinology and Reproductive Medicine, Berne, Switzerland
| | - G Otti
- University Women's Hospital, Division of Gynaecological Endocrinology and Reproductive Medicine, Berne, Switzerland
| | - R Schürch
- CTU Berne, Department of Clinical Research, Institute of Social and Preventive Medicine (ISPM), University of Berne, Berne, Switzerland
| | - S Rohner
- University Women's Hospital, Division of Gynaecological Endocrinology and Reproductive Medicine, Berne, Switzerland
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19
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Rohner S, Fäh M, Otti G, Kohl Schwartz A, Stute P, Schürch R, Wolff MV. Follikelspülungen bei Natural Cycle-IVF-Behandlungen verkürzen weder die Lutealphasenlänge noch die luteale Hormonsekretion – eine prospektiv kontrollierte Studie. Geburtshilfe Frauenheilkd 2016. [DOI: 10.1055/s-0036-1592771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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20
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Schürch R, Ratnieks FLW, Samuelson EEW, Couvillon MJ. Dancing to her own beat: honey bee foragers communicate via individually calibrated waggle dances. J Exp Biol 2016; 219:1287-9. [PMID: 26944504 DOI: 10.1242/jeb.134874] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/17/2016] [Indexed: 11/20/2022]
Abstract
Communication signals often vary between individuals, even when one expects selection to favour accuracy and precision, such as the honey bee waggle dance, where foragers communicate to nestmates the direction and distance to a resource. Although many studies have examined intra-dance variation, or the variation within a dance, less is known about inter-dance variation, or the variation between dances. This is particularly true for distance communication. Here, we trained individually marked bees from three colonies to forage at feeders of known distances and monitored their dances to determine individual communication variation. We found that each honey bee possesses her own calibration: individual duration-distance calibrations varied significantly in both slopes and intercepts. The variation may incur a cost for communication, such that a dancer and recruit may misunderstand the communicated distance by as much as 50%. Future work is needed to understand better the mechanisms and consequences of individual variation in communication.
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Affiliation(s)
- Roger Schürch
- Laboratory of Apiculture and Social Insects (LASI), University of Sussex, Brighton BN1 9QG, UK Clinical Trials Unit, University of Bern, CH-3012 Bern, Switzerland Institute of Social and Preventive Medicine (ISPM), University of Bern, CH-3012 Bern, Switzerland
| | - Francis L W Ratnieks
- Laboratory of Apiculture and Social Insects (LASI), University of Sussex, Brighton BN1 9QG, UK
| | - Elizabeth E W Samuelson
- Laboratory of Apiculture and Social Insects (LASI), University of Sussex, Brighton BN1 9QG, UK School of Biological Sciences, Royal Holloway University of London, Egham TW20 0EX, UK
| | - Margaret J Couvillon
- Laboratory of Apiculture and Social Insects (LASI), University of Sussex, Brighton BN1 9QG, UK
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21
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Schürch R, Couvillon MJ, Beekman M. Editorial: Ballroom Biology: Recent Insights into Honey Bee Waggle Dance Communications. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2015.00147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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22
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Couvillon M, Al Toufailia H, Butterfield T, Schrell F, Ratnieks F, Schürch R. Caffeinated Forage Tricks Honeybees into Increasing Foraging and Recruitment Behaviors. Curr Biol 2015. [DOI: 10.1016/j.cub.2015.10.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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23
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Couvillon MJ, Al Toufailia H, Butterfield TM, Schrell F, Ratnieks FLW, Schürch R. Caffeinated forage tricks honeybees into increasing foraging and recruitment behaviors. Curr Biol 2015; 25:2815-2818. [PMID: 26480843 DOI: 10.1016/j.cub.2015.08.052] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 08/19/2015] [Accepted: 08/24/2015] [Indexed: 12/01/2022]
Abstract
In pollination, plants provide food reward to pollinators who in turn enhance plant reproduction by transferring pollen, making the relationship largely cooperative; however, because the interests of plants and pollinators do not always align, there exists the potential for conflict, where it may benefit both to cheat the other [1, 2]. Plants may even resort to chemistry: caffeine, a naturally occurring, bitter-tasting, pharmacologically active secondary compound whose main purpose is to detract herbivores, is also found in lower concentrations in the nectar of some plants, even though nectar, unlike leaves, is made to be consumed by pollinators. [corrected]. A recent laboratory study showed that caffeine may lead to efficient and effective foraging by aiding honeybee memory of a learned olfactory association [4], suggesting that caffeine may enhance bee reward perception. However, without field data, the wider ecological significance of caffeinated nectar remains difficult to interpret. Here we demonstrate in the field that caffeine generates significant individual- and colony-level effects in free-flying worker honeybees. Compared to a control, a sucrose solution with field-realistic doses of caffeine caused honeybees to significantly increase their foraging frequency, waggle dancing probability and frequency, and persistency and specificity to the forage location, resulting in a quadrupling of colony-level recruitment. An agent-based model also demonstrates how caffeine-enhanced foraging may reduce honey storage. Overall, caffeine causes bees to overestimate forage quality, tempting the colony into sub-optimal foraging strategies, which makes the relationship between pollinator and plant less mutualistic and more exploitative. VIDEO ABSTRACT.
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Affiliation(s)
- Margaret J Couvillon
- Laboratory of Apiculture and Social Insects (LASI), School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK.
| | - Hasan Al Toufailia
- Laboratory of Apiculture and Social Insects (LASI), School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | | | - Felix Schrell
- Laboratory of Apiculture and Social Insects (LASI), School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Francis L W Ratnieks
- Laboratory of Apiculture and Social Insects (LASI), School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Roger Schürch
- Laboratory of Apiculture and Social Insects (LASI), School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK; Clinical Trials Unit (CTU), University of Bern, 3012 Bern, Switzerland
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24
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Abstract
Waggle dancing bees provide nestmates with spatial information about high quality resources. Surprisingly, attempts to quantify the benefits of this encoded spatial information have failed to find positive effects on colony foraging success under many ecological circumstances. Experimental designs have often involved measuring the foraging success of colonies that were repeatedly switched between oriented dances versus disoriented dances (i.e. communicating vectors versus not communicating vectors). However, if recruited bees continue to visit profitable food sources for more than one day, this procedure would lead to confounded results because of the long-term effects of successful recruitment events. Using agent-based simulations, we found that spatial information was beneficial in almost all ecological situations. Contrary to common belief, the benefits of recruitment increased with environmental stability because benefits can accumulate over time to outweigh the short-term costs of recruitment. Furthermore, we found that in simulations mimicking previous experiments, the benefits of communication were considerably underestimated (at low food density) or not detected at all (at medium and high densities). Our results suggest that the benefits of waggle dance communication are currently underestimated and that different experimental designs, which account for potential long-term benefits, are needed to measure empirically how spatial information affects colony foraging success.
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Affiliation(s)
- Roger Schürch
- Laboratory of Apiculture and Social Insects, School of Life Sciences, University of Sussex, Falmer, United Kingdom
| | - Christoph Grüter
- Departamento de Biologia da Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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Garbuzov M, Schürch R, Ratnieks FL. Eating locally: dance decoding demonstrates that urban honey bees in Brighton, UK, forage mainly in the surrounding urban area. Urban Ecosyst 2014. [DOI: 10.1007/s11252-014-0403-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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Couvillon MJ, Schürch R, Ratnieks FLW. Dancing bees communicate a foraging preference for rural lands in high-level agri-environment schemes. Curr Biol 2014; 24:1212-5. [PMID: 24856213 DOI: 10.1016/j.cub.2014.03.072] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 03/27/2014] [Accepted: 03/28/2014] [Indexed: 10/25/2022]
Abstract
Since 1994, more than €41 billion has been spent in the European Union on agri-environment schemes (AESs), which aim to mitigate the effects of anthropomorphic landscape changes via financial incentives for land managers to encourage environmentally friendly practices [1-6]. Surprisingly, given the substantial price tag and mandatory EU member participation [2], there is either a lack of [1] or mixed [1, 2, 7] evidence-based support for the schemes. One novel source of data to evaluate AESs may be provided by an organism that itself may benefit from them. Honeybees (Apis mellifera), important pollinators for crops and wildflowers [8, 9], are declining in parts of the world from many factors, including loss of available forage from agricultural intensification [10-13]. We analyzed landscape-level honeybee foraging ecology patterns over two years by decoding 5,484 waggle dances from bees located in the center of a mixed, urban-rural 94 km(2) area, including lands under government-funded AESs. The waggle dance, a unique behavior performed by successful foragers, communicates to nestmates the most profitable foraging locations [14-16]. After correcting for distance, dances demonstrate that honeybees possess a significant preference for rural land managed under UK Higher Level AESs and a significant preference against rural land under UK Organic Entry Level AESs. Additionally, the two most visited areas contained a National and Local Nature Reserve, respectively. Our study demonstrates that honeybees, with their great foraging range and sensitive response to forage quality, can be used as bioindicators to monitor large areas and provide information relevant to better environmental management.
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Affiliation(s)
- Margaret J Couvillon
- Laboratory of Apiculture and Social Insects, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK.
| | - Roger Schürch
- Laboratory of Apiculture and Social Insects, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK; Evolution, Behaviour, and Environment, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Francis L W Ratnieks
- Laboratory of Apiculture and Social Insects, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
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Couvillon MJ, Fensome KA, Quah SK, Schürch R. Summertime blues: August foraging leaves honey bees empty-handed. Commun Integr Biol 2014; 7:e28821. [PMID: 25346794 PMCID: PMC4203501 DOI: 10.4161/cib.28821] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [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: 04/06/2014] [Accepted: 04/08/2014] [Indexed: 11/21/2022] Open
Abstract
A successful honey bee forager tells her nestmates the location of good nectar and pollen with the waggle dance, a symbolic language that communicates a distance and direction. Because bees are adept at scouting out profitable forage and are very sensitive to energetic reward, we can use the distance that bees communicate via waggle dances as a proxy for forage availability, where the further the bees fly, the less forage can be found locally. Previously we demonstrated that bees fly furthest in the summer compared with spring or autumn to bring back forage that is not necessarily of better quality. Here we show that August is also the month when significantly more foragers return with empty crops (P = 7.63e-06). This provides additional support that summer may represent a seasonal foraging challenge for honey bees.
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Affiliation(s)
- Margaret J Couvillon
- Laboratory of Apiculture and Social Insects (LASI); School of Life Sciences; University of Sussex; Brighton, UK
| | - Katherine A Fensome
- Laboratory of Apiculture and Social Insects (LASI); School of Life Sciences; University of Sussex; Brighton, UK
| | - Shaun Kl Quah
- Laboratory of Apiculture and Social Insects (LASI); School of Life Sciences; University of Sussex; Brighton, UK
| | - Roger Schürch
- Laboratory of Apiculture and Social Insects (LASI); School of Life Sciences; University of Sussex; Brighton, UK
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Couvillon MJ, Schürch R, Ratnieks FLW. Waggle dance distances as integrative indicators of seasonal foraging challenges. PLoS One 2014; 9:e93495. [PMID: 24695678 PMCID: PMC3973573 DOI: 10.1371/journal.pone.0093495] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 03/06/2014] [Indexed: 11/18/2022] Open
Abstract
Even as demand for their services increases, honey bees (Apis mellifera) and other pollinating insects continue to decline in Europe and North America. Honey bees face many challenges, including an issue generally affecting wildlife: landscape changes have reduced flower-rich areas. One way to help is therefore to supplement with flowers, but when would this be most beneficial? We use the waggle dance, a unique behaviour in which a successful forager communicates to nestmates the location of visited flowers, to make a 2-year survey of food availability. We “eavesdropped” on 5097 dances to track seasonal changes in foraging, as indicated by the distance to which the bees as economic foragers will recruit, over a representative rural-urban landscape. In year 3, we determined nectar sugar concentration. We found that mean foraging distance/area significantly increase from springs (493 m, 0.8 km2) to summers (2156 m, 15.2 km2), even though nectar is not better quality, before decreasing in autumns (1275 m, 5.1 km2). As bees will not forage at long distances unnecessarily, this suggests summer is the most challenging season, with bees utilizing an area 22 and 6 times greater than spring or autumn. Our study demonstrates that dancing bees as indicators can provide information relevant to helping them, and, in particular, can show the months when additional forage would be most valuable.
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Affiliation(s)
- Margaret J Couvillon
- Laboratory of Apiculture and Social Insects, School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - Roger Schürch
- Laboratory of Apiculture and Social Insects, School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom; Laboratory of Social Evolution, School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - Francis L W Ratnieks
- Laboratory of Apiculture and Social Insects, School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
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Bigio G, Schürch R, Ratnieks FLW. Hygienic behavior in honey bees (Hymenoptera: Apidae): effects of brood, food, and time of the year. J Econ Entomol 2013; 106:2280-2285. [PMID: 24498725 DOI: 10.1603/ec13076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Hygienic behavior in honey bees is a heritable trait of individual workers that confers colony-level resistance against various brood diseases. Hygienic workers detect and remove dead or diseased brood from sealed cells. However, this behavior is quite rare, with only c.10% of unselected colonies showing high levels of hygiene. Beekeepers can potentially increase this by screening colonies for hygiene and breeding from the best. However, the level of hygiene expressed by a colony is variable, which poses a challenge to colony selection. In this study, we systematically varied two factors thought to be of importance in influencing hygiene levels, "nectar" availability, by feeding or not feeding sucrose syrup, and brood amount, by adding or removing brood, to determine what effect they had on hygienic behavior. We tested 19 colonies repeatedly over a 4-mo period using the freeze-killed brood assay, a standard technique to quantify hygienic behavior. Two days after freeze-killed brood treatment, our colonies showed a wide range of brood removal levels, with colony means ranging from 31.7 +/- 22.5 to 93 +/- 6.9 (mean % +/- SD). Neither the food nor the brood manipulation had an effect on hygiene levels. Colony size and time of year were also nonsignificant. The only significant effect was a three-way interaction between syrup availability, amount of brood, and time of the year, resulting in reduced hygienic behavior early in the season (spring), in colonies with added brood that were not fed sucrose syrup. Overall, these results suggest that hygienic behavior is not greatly affected by environmental conditions typical of a real-life beekeeping, and that screening of colonies can be done anytime without special regard to nectar conditions or brood levels.
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Affiliation(s)
- Gianluigi Bigio
- Laboratory of Apiculture and Social Insects, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom.
| | - Roger Schürch
- Evolution, Behaviour and Environment, School of Life Sciences, University of Sussex, Brighton BN19QG, United Kingdom
| | - Francis L W Ratnieks
- Laboratory of Apiculture and Social Insects, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom
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Schürch R, Couvillon MJ. Too much noise on the dance floor: Intra- and inter-dance angular error in honey bee waggle dances. Commun Integr Biol 2013; 6:e22298. [PMID: 23750292 PMCID: PMC3655781 DOI: 10.4161/cib.22298] [Citation(s) in RCA: 11] [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: 09/19/2012] [Accepted: 09/19/2012] [Indexed: 11/19/2022] Open
Abstract
Successful honey bee foragers communicate where they have found a good resource with the waggle dance, a symbolic language that encodes a distance and direction. Both of these components are repeated several times (1 to > 100) within the same dance. Additionally, both these components vary within a dance. Here we discuss some causes and consequences of intra-dance and inter-dance angular variation and advocate revisiting von Frisch and Lindauer’s earlier work to gain a better understanding of honey bee foraging ecology.
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Affiliation(s)
- Roger Schürch
- Social Evolution Research Group; School of Life Sciences; University of Sussex; Brighton, UK
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Grüter C, Schürch R, Farina WM. Task-partitioning in insect societies: Non-random direct material transfers affect both colony efficiency and information flow. J Theor Biol 2013; 327:23-33. [DOI: 10.1016/j.jtbi.2013.02.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 01/21/2013] [Accepted: 02/18/2013] [Indexed: 11/29/2022]
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Grüter C, Schürch R, Czaczkes TJ, Taylor K, Durance T, Jones SM, Ratnieks FLW. Negative feedback enables fast and flexible collective decision-making in ants. PLoS One 2012; 7:e44501. [PMID: 22984518 PMCID: PMC3440389 DOI: 10.1371/journal.pone.0044501] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 08/08/2012] [Indexed: 11/24/2022] Open
Abstract
Positive feedback plays a major role in the emergence of many collective animal behaviours. In many ants pheromone trails recruit and direct nestmate foragers to food sources. The strong positive feedback caused by trail pheromones allows fast collective responses but can compromise flexibility. Previous laboratory experiments have shown that when the environment changes, colonies are often unable to reallocate their foragers to a more rewarding food source. Here we show both experimentally, using colonies of Lasius niger, and with an agent-based simulation model, that negative feedback caused by crowding at feeding sites allows ant colonies to maintain foraging flexibility even with strong recruitment to food sources. In a constant environment, negative feedback prevents the frequently found bias towards one feeder (symmetry breaking) and leads to equal distribution of foragers. In a changing environment, negative feedback allows a colony to quickly reallocate the majority of its foragers to a superior food patch that becomes available when foraging at an inferior patch is already well underway. The model confirms these experimental findings and shows that the ability of colonies to switch to a superior food source does not require the decay of trail pheromones. Our results help to resolve inconsistencies between collective foraging patterns seen in laboratory studies and observations in the wild, and show that the simultaneous action of negative and positive feedback is important for efficient foraging in mass-recruiting insect colonies.
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Affiliation(s)
- Christoph Grüter
- Laboratory of Apiculture and Social Insects, School of Life Sciences, University of Sussex, Falmer, United Kingdom.
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Couvillon MJ, Phillipps HLF, Schürch R, Ratnieks FLW. Working against gravity: horizontal honeybee waggle runs have greater angular scatter than vertical waggle runs. Biol Lett 2012; 8:540-3. [PMID: 22513277 DOI: 10.1098/rsbl.2012.0182] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The presence of noise in a communication system may be adaptive or may reflect unavoidable constraints. One communication system where these alternatives are debated is the honeybee (Apis mellifera) waggle dance. Successful foragers communicate resource locations to nest-mates by a dance comprising repeated units (waggle runs), which repetitively transmit the same distance and direction vector from the nest. Intra-dance waggle run variation occurs and has been hypothesized as a colony-level adaptation to direct recruits over an area rather than a single location. Alternatively, variation may simply be due to constraints on bees' abilities to orient waggle runs. Here, we ask whether the angle at which the bee dances on vertical comb influences waggle run variation. In particular, we determine whether horizontal dances, where gravity is not aligned with the waggle run orientation, are more variable in their directional component. We analysed 198 dances from foragers visiting natural resources and found support for our prediction. More horizontal dances have greater angular variation than dances performed close to vertical. However, there is no effect of waggle run angle on variation in the duration of waggle runs, which communicates distance. Our results weaken the hypothesis that variation is adaptive and provide novel support for the constraint hypothesis.
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Affiliation(s)
- Margaret J Couvillon
- Laboratory of Apiculture and Social Insects, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK.
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Couvillon MJ, Riddell Pearce FC, Harris-Jones EL, Kuepfer AM, Mackenzie-Smith SJ, Rozario LA, Schürch R, Ratnieks FLW. Intra-dance variation among waggle runs and the design of efficient protocols for honey bee dance decoding. Biol Open 2012; 1:467-72. [PMID: 23213438 PMCID: PMC3507209 DOI: 10.1242/bio.20121099] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [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] [Indexed: 11/20/2022] Open
Abstract
Noise is universal in information transfer. In animal communication, this presents a challenge not only for intended signal receivers, but also to biologists studying the system. In honey bees, a forager communicates to nestmates the location of an important resource via the waggle dance. This vibrational signal is composed of repeating units (waggle runs) that are then averaged by nestmates to derive a single vector. Manual dance decoding is a powerful tool for studying bee foraging ecology, although the process is time-consuming: a forager may repeat the waggle run 1- >100 times within a dance. It is impractical to decode all of these to obtain the vector; however, intra-dance waggle runs vary, so it is important to decode enough to obtain a good average. Here we examine the variation among waggle runs made by foraging bees to devise a method of dance decoding. The first and last waggle runs within a dance are significantly more variable than the middle run. There was no trend in variation for the middle waggle runs. We recommend that any four consecutive waggle runs, not including the first and last runs, may be decoded, and we show that this methodology is suitable by demonstrating the goodness-of-fit between the decoded vectors from our subsamples with the vectors from the entire dances.
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Chervet N, Zöttl M, Schürch R, Taborsky M, Heg D. Repeatability and heritability of behavioural types in a social cichlid. Int J Evol Biol 2011; 2011:321729. [PMID: 21716729 PMCID: PMC3119426 DOI: 10.4061/2011/321729] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Accepted: 02/28/2011] [Indexed: 11/27/2022]
Abstract
Aim. The quantitative genetics underlying correlated behavioural traits (''animal personality") have hitherto been studied mainly in domesticated animals. Here we report the repeatability (R) and heritability (h(2)) of behavioural types in the highly social cichlid fish Neolamprologus pulcher. Methods. We tested 1779 individuals repeatedly and calculated the h(2) of behavioural types by variance components estimation (GLMM REML), using 1327 offspring from 162 broods from 74 pairs. Results. Repeatability of behavioural types was significant and considerable (0.546), but declined from 0.83 between tests conducted on the same day, to 0.19 on tests conducted up to 1201 days apart. All h(2) estimates were significant but low (e.g., pair identity h(2) = 0.15 ± 0.03 SE). Additionally, we found significant variation between broods nested within the parent(s), but these were not related to several environmental factors tested. Conclusions. We conclude that despite a considerable R, h(2) in this cichlid species is low, and variability in behavioural type appears to be strongly affected by other (non)genetic effects.
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Affiliation(s)
- Noémie Chervet
- Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, 3032 Hinterkappelen, Switzerland
| | - Markus Zöttl
- Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, 3032 Hinterkappelen, Switzerland
| | - Roger Schürch
- Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, 3032 Hinterkappelen, Switzerland
| | - Michael Taborsky
- Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, 3032 Hinterkappelen, Switzerland
| | - Dik Heg
- Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, 3032 Hinterkappelen, Switzerland
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Schürch R, Rothenberger S, Heg D. The building-up of social relationships: behavioural types, social networks and cooperative breeding in a cichlid. Philos Trans R Soc Lond B Biol Sci 2010; 365:4089-98. [PMID: 21078660 PMCID: PMC2992742 DOI: 10.1098/rstb.2010.0177] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Consistent individual differences in behavioural types may not only cause variation in life-history decisions, but may also affect the choice of social partners and sociality in general. Here, we tested whether and how behavioural type influences the establishment of social ties using the cooperatively breeding cichlid, Neolamprologus pulcher. In a habitat saturation experiment with individuals pre-tested for behavioural type, we first analysed whether behavioural type affected the likelihood of settlement (i.e. social status), group sizes, and the types of dominant and subordinate individuals accepted as group members. Corrected for effects of body size and sex, the behavioural type did not affect settlement. However, bold dominant males only accepted smaller females, and grouped with bold subordinates, while shy dominant males accepted larger females than themselves, and grouped with shy subordinates. Second, we analysed the relationships between behavioural type and the aggressiveness or affiliation social network. Behavioural type significantly affected the number and quality of connections within the two networks. We show that behavioural types affect group composition, social networks and status achieved, in interaction with body size. Thus, the interactions within groups may depend not only on age, size and sex, but also on the behavioural type of the individuals involved.
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Affiliation(s)
- Roger Schürch
- Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50a, CH-3032 Hinterkappelen, Switzerland
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Susan Rothenberger
- Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50a, CH-3032 Hinterkappelen, Switzerland
| | - Dik Heg
- Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50a, CH-3032 Hinterkappelen, Switzerland
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Heg D, Rothenberger S, Schürch R. Habitat saturation, benefits of philopatry, relatedness, and the extent of co-operative breeding in a cichlid. Behav Ecol 2010. [DOI: 10.1093/beheco/arq170] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Witsenburg F, Schürch R, Otti O, Heg D. Behavioural types and ecological effects in a natural population of the cooperative cichlid Neolamprologus pulcher. Anim Behav 2010. [DOI: 10.1016/j.anbehav.2010.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Bergmüller R, Schürch R, Hamilton IM. Evolutionary causes and consequences of consistent individual variation in cooperative behaviour. Philos Trans R Soc Lond B Biol Sci 2010; 365:2751-64. [PMID: 20679117 PMCID: PMC2936170 DOI: 10.1098/rstb.2010.0124] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Behaviour is typically regarded as among the most flexible of animal phenotypic traits. In particular, expression of cooperative behaviour is often assumed to be conditional upon the behaviours of others. This flexibility is a key component of many hypothesized mechanisms favouring the evolution of cooperative behaviour. However, evidence shows that cooperative behaviours are often less flexible than expected and that, in many species, individuals show consistent differences in the amount and type of cooperative and non-cooperative behaviours displayed. This phenomenon is known as 'animal personality' or a 'behavioural syndrome'. Animal personality is evolutionarily relevant, as it typically shows heritable variation and can entail fitness consequences, and hence, is subject to evolutionary change. Here, we review the empirical evidence for individual variation in cooperative behaviour across taxa, we examine the evolutionary processes that have been invoked to explain the existence of individual variation in cooperative behaviour and we discuss the consequences of consistent individual differences on the evolutionary stability of cooperation. We highlight that consistent individual variation in cooperativeness can both stabilize or disrupt cooperation in populations. We conclude that recognizing the existence of consistent individual differences in cooperativeness is essential for an understanding of the evolution and prevalence of cooperation.
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Affiliation(s)
- Ralph Bergmüller
- Department of Biology, University of Neuchâtel, 2009 Neuchâtel, Switzerland.
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Abstract
The mouthbrooding cichlid Tropheus moorii exhibits an exceptional degree of maternal investment. Females produce very large eggs, which are incubated for a period of six weeks, and they feed their young in the mouth while starving themselves. Only very few fish species are known to feed their young. We hypothesized that feeding may either (1) benefit females directly if young develop faster, or (2) provide a size advantage to young. To distinguish between these mutually non-exclusive hypotheses, we measured costs and benefits arising for mouthbrooding females when feeding their young. Field observations revealed that mouthbrooding females reduced bite rates, locomotion and territorial defence compared to non-brooding adults. Feeding rates correlated positively with locomotion, as fish moving around more also spent more time with territory defence and other social interactions. This suggests that buccal feeding is costly when compared to mere incubation without feeding the young. In an experiment, in which we controlled the access of females to food, we showed that these costs are apparently not counterbalanced by a benefit to females through a shorter incubation duration. Rather, fed young were larger, heavier and had higher burst-swimming speeds. The extreme maternal investment of T. moorii appears to yield fitness benefits to females by producing larger and stronger young, which consequently should have better survival chances in their natural environment.
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