LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 49

Search options

  1. Article: Initial floral visitor identity and foraging time strongly influence blueberry reproductive success

    Kendall, Liam K. / Stavert, Jamie R. / Gagic, Vesna / Hall, Mark / Rader, Romina

    Basic and applied ecology. 2022 May, v. 60

    2022  

    Abstract: Priority effects occur when the order of species arrival affects subsequent ecological processes. The order that pollinator species visit flowers may affect pollination through a priority effect, whereby the first visitor reduces or modifies the ... ...

    Abstract Priority effects occur when the order of species arrival affects subsequent ecological processes. The order that pollinator species visit flowers may affect pollination through a priority effect, whereby the first visitor reduces or modifies the contribution of subsequent visits. We observed floral visitation to blueberry flowers from honeybees, stingless bees or a mixture of both species and investigated how (i) initial visits differed in duration to later visits; and (ii) how visit sequences from different pollinator taxa influenced fruit weight. Stingless bees visited blueberry flowers for significantly longer than honeybees and maintained their floral visit duration, irrespective of the number of preceding visits. In contrast, honeybee visit duration declined significantly with an increasing number of preceding visits. Fruit weight was positively associated with longer floral visit duration by honeybees but not from stingless bee or mixed species visitation. Fruit from mixed species visits were heavier overall than single species visits, because of a strong priority effect. An initial visit by a stingless bee fully pollinated the flower, limiting the pollination contribution of future visitors. However, after an initial honeybee visit, flowers were not fully pollinated and additional visitation had an additive effect upon fruit weight. Blueberries from flowers visited first by stingless bees were 60% heavier than those visited first by honeybees when total floral visitation was short (∼1 min). However, when total visitation time was long (∼ 8 min), blueberry fruit were 24% heavier when initial visits were from honeybees. Our findings highlight that the initial floral visit can have a disproportionate effect on pollination outcomes. Considering priority effects alongside traditional measures of pollinator effectiveness will provide a greater mechanistic understanding of how pollinator communities influence plant reproductive success.
    Keywords additive effect ; applied ecology ; blueberries ; flowers ; fruit weight ; fruits ; pollination ; pollinators ; reproductive success ; stingless bees
    Language English
    Dates of publication 2022-05
    Size p. 114-122.
    Publishing place Elsevier GmbH
    Document type Article
    ZDB-ID 2026806-3
    ISSN 1439-1791
    ISSN 1439-1791
    DOI 10.1016/j.baae.2022.02.009
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  2. Article: Additive and interactive effects of pollination and biological pest control on crop yield

    Gagic, Vesna / Howie, Lynita / Marcora, Anna

    Journal of applied ecology. 2019 Nov., v. 56, no. 11

    2019  

    Abstract: Insect pollination and biological pest control simultaneously influence crop yield, but are often investigated individually. This can lead to under‐ or over‐estimation of the importance of individual services when they interact to affect yield. Recent, ... ...

    Abstract Insect pollination and biological pest control simultaneously influence crop yield, but are often investigated individually. This can lead to under‐ or over‐estimation of the importance of individual services when they interact to affect yield. Recent, limited evidence from field studies showed contrasting results with both additive and non‐additive positive and negative effects. To disentangle the mechanisms underlying these responses, we conducted a greenhouse experiment and a field study. We tested the potential and realized contribution of insect pollination to cotton boll retention and yield under various pest pressures and biocontrol levels. We found both additive and interactive effects of insect pollination and biocontrol within a single crop system depending on the level of pest pressure. In the greenhouse experiment, pollination did not contribute to cotton boll retention and final yield at low pest pressure. At high pest abundances, boll retention and final yield were higher when pollinators were present. In the field study, pollination was sufficient to alter the negative effect of pests on boll retention. Thus, interactive effect between the two ecosystem services on boll retention was present at high pest pressure in the greenhouse and at natural levels of pest pressure in the field, but not at lower pest abundances in controlled conditions. Although cotton plants partly compensated for bolls shedding by increasing their weight in the greenhouse experiment, this effect was not detected in the field study, likely due to higher environmental variation. Similarly, interactive effect of pollination and biocontrol on the final yield was present only in the greenhouse study. Synthesis and applications. We conclude that the contrasting findings of additive versus non‐additive effects between ecosystem services may be due to the levels of services and disservices tested and environmental variation. Further, this study shows that even when an ecosystem service does not appear to limit crop yield, it can make a substantial contribution to yield and act as insurance when the other service is reduced. For achieving food and fibre security, it is essential that future studies test interactive effects between these ecosystem services in different systems and environmental conditions.
    Keywords biological pest control ; bolls ; cotton ; crop yield ; ecosystem services ; environmental factors ; Gossypium ; greenhouse experimentation ; greenhouses ; insect pollination ; pests ; pollinators
    Language English
    Dates of publication 2019-11
    Size p. 2528-2535.
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 410405-5
    ISSN 1365-2664 ; 0021-8901
    ISSN (online) 1365-2664
    ISSN 0021-8901
    DOI 10.1111/1365-2664.13482
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  3. Article: Flower strips enhance abundance of bumble bee queens and males in landscapes with few honey bee hives

    Bommarco, Riccardo / Lindström, Sandra A.M. / Raderschall, Chloé A. / Gagic, Vesna / Lundin, Ola

    Biological conservation. 2021 Nov., v. 263

    2021  

    Abstract: Wild bee declines in agricultural landscapes have led farmers to supplement crops with honey bees. Simultaneously, environmental subsidy and conservation programmes have incentivized farmers to establish flower strips to support wild and managed ... ...

    Abstract Wild bee declines in agricultural landscapes have led farmers to supplement crops with honey bees. Simultaneously, environmental subsidy and conservation programmes have incentivized farmers to establish flower strips to support wild and managed pollinators. To find out if flower strips enhance, and competition from honey bees suppresses, wild bees in the landscape and across seasons, we surveyed bumble bee and honey bee abundances in 16 sites in Sweden in summer 2018. The centre of each site (2 km radius) was with or without an annual flower strip, and with or without added honey bee hives. We surveyed bees in each flower strip and in linear habitats in the landscape around each site, such as field edges and road verges. In the following spring, we surveyed bumble bee queen abundance in each site. We show that adding flower strips benefits bumble bee queen abundance the following year, but this effect is diminished if honeybee hives are added. In sites with flower strips, added honey bee hives reduced male bumble bee abundance. Our relatively small flower strip areas bolstered bumble bee population growth across seasons, probably by relieving a resource bottleneck. Adding honey bee hives in combination with flower strips to landscapes with few floral resources should be avoided as it cancelled the positive effect of flower strips.
    Keywords Bombus ; beehives ; flowers ; honey ; landscapes ; males ; population growth ; spring ; summer ; Sweden
    Language English
    Dates of publication 2021-11
    Publishing place Elsevier Ltd
    Document type Article
    ISSN 0006-3207
    DOI 10.1016/j.biocon.2021.109363
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  4. Article ; Online: Better outcomes for pest pressure, insecticide use, and yield in less intensive agricultural landscapes.

    Gagic, Vesna / Holding, Matthew / Venables, William N / Hulthen, Andrew D / Schellhorn, Nancy A

    Proceedings of the National Academy of Sciences of the United States of America

    2021  Volume 118, Issue 12

    Abstract: Agricultural systems have been continuously intensified to meet rising demand for agricultural products. However, there are increasing concerns that larger, more connected crop fields and loss of seminatural areas exacerbate pest pressure, but findings ... ...

    Abstract Agricultural systems have been continuously intensified to meet rising demand for agricultural products. However, there are increasing concerns that larger, more connected crop fields and loss of seminatural areas exacerbate pest pressure, but findings to date have been inconclusive. Even less is known about whether increased pest pressure results in measurable effects for farmers, such as increased insecticide use and decreased crop yield. Using extensive spatiotemporal data sampled every 2 to 3 d throughout five growing seasons in 373 cotton fields, we show that pests immigrated earlier and were more likely to occur in larger cotton fields embedded in landscapes with little seminatural area (<10%). Earlier pest immigration resulted in earlier spraying that was further linked to more sprays per season. Importantly, crop yield was the lowest in these intensified landscapes. Our results demonstrate that both environmental conservation and production objectives can be achieved in conventional agriculture by decreasing field sizes and maintaining seminatural vegetation in the surrounding landscapes.
    MeSH term(s) Agriculture ; Crops, Agricultural ; Environmental Restoration and Remediation ; Farmers ; Insecticides/administration & dosage ; Pest Control ; Seasons ; Spatio-Temporal Analysis
    Chemical Substances Insecticides
    Language English
    Publishing date 2021-03-17
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.2018100118
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Book ; Online ; Thesis: Agricultural intensification, biological pest control and spatio-temporal changes in food web structure

    Gagic, Vesna

    2011  

    Abstract: Agricultural intensification (AI) is a major driver of losses in agrobiodiversity and associated ecosystem functions such as biological control, thereby indirectly affecting agricultural production. AI may influence community structure, composition and ... ...

    Title variant Intensivierung der Landwirtschaft, biologische Schädlingsbekämpfung und räumlich-zeitliche Veränderungen in der Struktur des Nahrungsnetzes
    Author's details vorgelegt von Vesna Gagic
    Abstract Agricultural intensification (AI) is a major driver of losses in agrobiodiversity and associated ecosystem functions such as biological control, thereby indirectly affecting agricultural production. AI may influence community structure, composition and variability in both space and time, by differently affecting species with different traits. Species at higher trophic levels, with higher specialization and lower dispersal abilities, are expected to be more vulnerable to AI and have high spatio-temporal population and food-web dynamic. Hence, understanding patterns of agrobiodiversity and their associated trophic interactions, as well as species turnover due to AI, requires a focus on the spatio-temporal changes in communities belonging to different feeding guilds and trophic levels. The aim of this study is to address these patterns in agrobiodiversity and to investigate their relation to biological-control functioning in different land-use systems. This work is part of the AGRIPOPES project (http://agripopes.net) and comprises three field studies, carried out in the surroundings of Göttingen, Lower Saxony, Germany ...
    Language English
    Size Online-Ressource (PDF-Datei: 91 S., 4.076 KB), Ill., graph. Darst
    Document type Book ; Online ; Thesis
    Thesis / German Habilitation thesis Univ., Diss.--Göttingen, 2011
    Database Former special subject collection: coastal and deep sea fishing

    More links

    Kategorien

  6. Book ; Online ; Thesis: Agricultural intensification, biological pest control and spatio-temporal changes in food web structure

    Gagic, Vesna

    2011  

    Abstract: Agricultural intensification (AI) is a major driver of losses in agrobiodiversity and associated ecosystem functions such as biological control, thereby indirectly affecting agricultural production. AI may influence community structure, composition and ... ...

    Title variant Intensivierung der Landwirtschaft, biologische Schädlingsbekämpfung und räumlich-zeitliche Veränderungen in der Struktur des Nahrungsnetzes
    Author's details vorgelegt von Vesna Gagic
    Abstract Agricultural intensification (AI) is a major driver of losses in agrobiodiversity and associated ecosystem functions such as biological control, thereby indirectly affecting agricultural production. AI may influence community structure, composition and variability in both space and time, by differently affecting species with different traits. Species at higher trophic levels, with higher specialization and lower dispersal abilities, are expected to be more vulnerable to AI and have high spatio-temporal population and food-web dynamic. Hence, understanding patterns of agrobiodiversity and their associated trophic interactions, as well as species turnover due to AI, requires a focus on the spatio-temporal changes in communities belonging to different feeding guilds and trophic levels. The aim of this study is to address these patterns in agrobiodiversity and to investigate their relation to biological-control functioning in different land-use systems. This work is part of the AGRIPOPES project (http://agripopes.net) and comprises three field studies, carried out in the surroundings of Göttingen, Lower Saxony, Germany ...
    Language English
    Size Online-Ressource (PDF-Datei: 91 S., 4.076 KB), Ill., graph. Darst
    Document type Book ; Online ; Thesis
    Thesis / German Habilitation thesis Univ., Diss.--Göttingen, 2011
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

    More links

    Kategorien

  7. Article: Understanding pollinator foraging behaviour and transition rates between flowers is important to maximize seed set in hybrid crops

    Gagic, Vesna / Kirkland, Lindsey / Kendall, Liam K / Jones, Jeremy / Kirkland, Jeffrey / Spurr, Cameron / Rader, Romina

    Apidologie. 2021 Feb., v. 52, no. 1

    2021  

    Abstract: Hybrid cauliflower production predominately relies on pollen transfer from hermaphrodite to female lines by honeybees. However, the presence of other pollinators may impact pollination success. Here, we investigate how honeybee visitation frequency and ... ...

    Abstract Hybrid cauliflower production predominately relies on pollen transfer from hermaphrodite to female lines by honeybees. However, the presence of other pollinators may impact pollination success. Here, we investigate how honeybee visitation frequency and behaviour vary with plant sex and presence of blowflies and affect seed and pod set. We found substantial pollen limitation when honeybees were alone. This was likely due to their higher visitation to hermaphrodite flowers, infrequent transition from hermaphrodite to female flowers and high nectar theft in female flowers. Pollen foragers fed on nectar on hermaphrodite, but not female flowers. Moreover, when blowflies were present, the seed set was lower than that with honeybees alone. Our study highlights the importance of understanding the plant mating system and pollinator foraging behaviour with and without other species present in order to maximize seed set in hybrid crops.
    Keywords cauliflower ; females ; hermaphroditism ; honey bees ; hybrids ; nectar ; pollen ; pollination ; pollinators ; seed set
    Language English
    Dates of publication 2021-02
    Size p. 89-100.
    Publishing place Springer Paris
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 280429-3
    ISSN 1297-9678 ; 0044-8435 ; 0365-5407
    ISSN (online) 1297-9678
    ISSN 0044-8435 ; 0365-5407
    DOI 10.1007/s13592-020-00800-2
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  8. Article: Biocontrol in insecticide sprayed crops does not benefit from semi‐natural habitats and recovers slowly after spraying

    Gagic, Vesna / Hulthen, Andrew D / Jones, Laura / Marcora, Anna / Schellhorn, Nancy A / Wang, Xiaobei

    Journal of applied ecology. 2019 Sept., v. 56, no. 9

    2019  

    Abstract: To enhance biological pest control in crop fields, it is recommended to increase semi‐natural area on farm and decrease insecticide spraying. While the benefits of semi‐natural area for biocontrol in unsprayed fields are often demonstrated, it remains ... ...

    Abstract To enhance biological pest control in crop fields, it is recommended to increase semi‐natural area on farm and decrease insecticide spraying. While the benefits of semi‐natural area for biocontrol in unsprayed fields are often demonstrated, it remains largely unknown if there are any benefits in real‐world, commonly sprayed crops. Here, we explored the combined effects of semi‐natural field margins and insecticide spraying on pest (cotton bollworm) egg predation in 53 Australian cotton fields and semi‐natural field margins across 2 years. We used predation experiments close to field edges to exclude functional groups of predators depending on their spatio‐temporal activity (diurnal vs. nocturnal and ground vs. canopy dwelling) and digital cameras to record natural enemy taxa responsible for predation. Ground predation was substantially higher than canopy predation and its magnitude in unsprayed crops with semi‐natural margins was similar to that within semi‐natural areas. In contrast, semi‐natural field margins did not benefit biocontrol in sprayed crop fields and did not influence recovery rate of biocontrol after spraying. Within ground‐dwelling predators, one dominant taxon contributed the most to biocontrol at a particular time and place. However, the dominant predator–prey interactions changed between day and night and fields with and without margins, thus indicating increased importance of additional predator taxa with increasing spatio‐temporal scales. Synthesis and applications. Our results show that semi‐natural margins benefit pest control only in unsprayed fields. Spraying at different time (e.g. during night) would not reduce the negative effects of insecticides because it would affect complementary group of nocturnal natural enemies that exert equally high biocontrol as diurnal ground‐dwelling predators. We highlight the need for management recommendations to simultaneously consider pros and cons of within‐field spraying and surrounding semi‐natural habitats to maximize their benefits in high‐input conventional production systems.
    Keywords biological pest control ; cameras ; canopy ; cotton ; crops ; edge effects ; eggs ; farms ; habitats ; Helicoverpa armigera ; insecticides ; natural enemies ; pests ; predation ; predator-prey relationships ; predators ; production technology ; spraying
    Language English
    Dates of publication 2019-09
    Size p. 2176-2185.
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 410405-5
    ISSN 1365-2664 ; 0021-8901
    ISSN (online) 1365-2664
    ISSN 0021-8901
    DOI 10.1111/1365-2664.13452
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  9. Article ; Online: Time will tell: resource continuity bolsters ecosystem services.

    Schellhorn, Nancy A / Gagic, Vesna / Bommarco, Riccardo

    Trends in ecology & evolution

    2015  Volume 30, Issue 9, Page(s) 524–530

    Abstract: A common suggestion to support ecosystem services to agriculture provided by mobile organisms is to increase the amount of natural and seminatural habitat in the landscape. This might, however, be inefficient, and demands for agricultural products limit ... ...

    Abstract A common suggestion to support ecosystem services to agriculture provided by mobile organisms is to increase the amount of natural and seminatural habitat in the landscape. This might, however, be inefficient, and demands for agricultural products limit the feasibility of converting arable land into natural habitat. To develop more targeted means to promote ecosystem services, we need a solid understanding of the limitations to population growth for service-providing organisms. We propose a research agenda that identifies resource bottlenecks and interruptions over time to key beneficial organisms, emphasising their resulting population dynamics. Targeted measures that secure the continuity of resources throughout the life cycle of service-providing organisms are likely to effectively increase the stock, flow, and stability of ecosystem services.
    MeSH term(s) Agriculture/methods ; Animals ; Conservation of Natural Resources ; Ecosystem ; Life Cycle Stages ; Population Dynamics ; Time Factors
    Language English
    Publishing date 2015-09
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 284965-3
    ISSN 1872-8383 ; 0169-5347
    ISSN (online) 1872-8383
    ISSN 0169-5347
    DOI 10.1016/j.tree.2015.06.007
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article ; Online: Insecticide resistance in pollen beetles over 7 years - a landscape approach.

    Riggi, Laura G A / Gagic, Vesna / Bommarco, Riccardo / Ekbom, Barbara

    Pest management science

    2016  Volume 72, Issue 4, Page(s) 780–786

    Abstract: Background: In spite of considerable interest in the impact of pesticides on pest populations, few attempts have been made to link resistance patterns of insect pests to land-use features across spatial and temporal scales. We hypothesise that pollen ... ...

    Abstract Background: In spite of considerable interest in the impact of pesticides on pest populations, few attempts have been made to link resistance patterns of insect pests to land-use features across spatial and temporal scales. We hypothesise that pollen beetle pesticide resistance increases in areas with a high proportion of oilseed rape and with an even mixture of winter and spring oilseed rape owing to high pesticide selection pressure in such areas.
    Results: Here, we investigated 7 years of lambda-cyhalothrin (Karate(®) ) resistance in field-collected pollen beetle adults from a total of 180 sampling points across ten regions in Sweden. We found a positive effect on pollen beetle pesticide resistance of proportion of oilseed rape and even spring-winter oilseed rape mixture. However, this was true only for the regional spatial scale. Significant land-use effects in the long-term models, with oilseed rape data averaged over a longer (4 years) period of time, suggested an effect of regional landscape history on current pest resistance.
    Conclusion: For successful control of pollen beetle pesticide resistance, we suggest a long-term regional strategy for oilseed rape management. This land-use approach provides a framework for further investigations that integrate resistance management into landscape research.
    MeSH term(s) Animals ; Coleoptera/drug effects ; Evolution, Molecular ; Insecticide Resistance/genetics ; Nitriles/pharmacology ; Pyrethrins/pharmacology ; Selection, Genetic
    Chemical Substances Nitriles ; Pyrethrins ; cyhalothrin (V0V73PEB8M)
    Language English
    Publishing date 2016-04
    Publishing country England
    Document type Journal Article
    ZDB-ID 2001705-4
    ISSN 1526-4998 ; 1526-498X
    ISSN (online) 1526-4998
    ISSN 1526-498X
    DOI 10.1002/ps.4052
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top