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Nocturnal pollination: an overlooked ecosystem service vulnerable to environmental change. Emerg Top Life Sci 2020; 4:19-32. [PMID: 32478390 PMCID: PMC7326339 DOI: 10.1042/etls20190134] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/14/2022]
Abstract
Existing assessments of the ecosystem service of pollination have been largely restricted to diurnal insects, with a particular focus on generalist foragers such as wild and honey bees. As knowledge of how these plant-pollinator systems function, their relevance to food security and biodiversity, and the fragility of these mutually beneficial interactions increases, attention is diverting to other, less well-studied pollinator groups. One such group are those that forage at night. In this review, we document evidence that nocturnal species are providers of pollination services (including pollination of economically valuable and culturally important crops, as well as wild plants of conservation concern), but highlight how little is known about the scale of such services. We discuss the primary mechanisms involved in night-time communication between plants and insect pollen-vectors, including floral scent, visual cues (and associated specialized visual systems), and thermogenic sensitivity (associated with thermogenic flowers). We highlight that these mechanisms are vulnerable to direct and indirect disruption by a range of anthropogenic drivers of environmental change, including air and soil pollution, artificial light at night, and climate change. Lastly, we highlight a number of directions for future research that will be important if nocturnal pollination services are to be fully understood and ultimately conserved.
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Mazón M, Nuñez-Penichet C, Cobos ME. Relationship Between Body Mass and Forewing Length in Neotropical Ichneumonidae (Insecta: Hymenoptera). NEOTROPICAL ENTOMOLOGY 2020; 49:713-721. [PMID: 32557404 DOI: 10.1007/s13744-020-00784-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 05/05/2020] [Indexed: 06/11/2023]
Abstract
Biomass is an important indicator of various ecological factors in insect populations and communities. Although the utility of this variable is proven, it is usually dismissed in ecological studies, generally, because of the difficulty of measuring it. Considering that insect biomass is apparently declining worldwide, here, we aimed to test the accuracy of forewing length as an estimator of body mass in Neotropical Ichneumonidae to help in monitoring insect biomass. Forewing length and dry body mass were measured in 728 individuals from distinct localities in Venezuela and Ecuador. A clear log-linear relationship existed between the two variables, and a log-linear regression had significant and strong predictive power of mass based on wing length. To derive the final values of mass from predictions made using our equation, we used an exponential transformation. We present an R function for predicting mass from wing length. We consider our findings applicable to many Neotropical species of Ichneumonidae, and helpful especially when specimens are measured in dry collections.
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Affiliation(s)
- M Mazón
- Programa de Investigación en Biodiversidad y Servicios Ecosistémicos, Univ Nacional de Loja, Ciudadela Universitaria, sector La Argelia, EC 110101, Loja, Ecuador.
- Depto de Ciencias Ambientales y Recursos Naturales, Univ de Alicante, Alicante, Spain.
| | - C Nuñez-Penichet
- Programa de Investigación en Biodiversidad y Servicios Ecosistémicos, Univ Nacional de Loja, Ciudadela Universitaria, sector La Argelia, EC 110101, Loja, Ecuador
- Dept of Ecology and Evolutionary Biology & Biodiversity Institute, Univ of Kansas, Lawrence, KS, USA
| | - M E Cobos
- Programa de Investigación en Biodiversidad y Servicios Ecosistémicos, Univ Nacional de Loja, Ciudadela Universitaria, sector La Argelia, EC 110101, Loja, Ecuador
- Dept of Ecology and Evolutionary Biology & Biodiversity Institute, Univ of Kansas, Lawrence, KS, USA
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Crossley MS, Meier AR, Baldwin EM, Berry LL, Crenshaw LC, Hartman GL, Lagos-Kutz D, Nichols DH, Patel K, Varriano S, Snyder WE, Moran MD. No net insect abundance and diversity declines across US Long Term Ecological Research sites. Nat Ecol Evol 2020; 4:1368-1376. [PMID: 32778751 DOI: 10.1038/s41559-020-1269-4] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 06/26/2020] [Indexed: 11/09/2022]
Abstract
Recent reports of dramatic declines in insect abundance suggest grave consequences for global ecosystems and human society. Most evidence comes from Europe, however, leaving uncertainty about insect population trends worldwide. We used >5,300 time series for insects and other arthropods, collected over 4-36 years at monitoring sites representing 68 different natural and managed areas, to search for evidence of declines across the United States. Some taxa and sites showed decreases in abundance and diversity while others increased or were unchanged, yielding net abundance and biodiversity trends generally indistinguishable from zero. This lack of overall increase or decline was consistent across arthropod feeding groups and was similar for heavily disturbed versus relatively natural sites. The apparent robustness of US arthropod populations is reassuring. Yet, this result does not diminish the need for continued monitoring and could mask subtler changes in species composition that nonetheless endanger insect-provided ecosystem services.
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Affiliation(s)
| | - Amanda R Meier
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - Emily M Baldwin
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
| | - Lauren L Berry
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
| | - Leah C Crenshaw
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
| | - Glen L Hartman
- Agricultural Research Service, United States Department of Agriculture, Urbana, IL, USA
| | - Doris Lagos-Kutz
- Agricultural Research Service, United States Department of Agriculture, Urbana, IL, USA
| | - David H Nichols
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
| | - Krishna Patel
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
| | - Sofia Varriano
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
| | - William E Snyder
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - Matthew D Moran
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
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Kinsella RS, Thomas CD, Crawford TJ, Hill JK, Mayhew PJ, Macgregor CJ. Unlocking the potential of historical abundance datasets to study biomass change in flying insects. Ecol Evol 2020; 10:8394-8404. [PMID: 32788988 PMCID: PMC7417223 DOI: 10.1002/ece3.6546] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 11/08/2022] Open
Abstract
Trends in insect abundance are well established in some datasets, but far less is known about how abundance measures translate into biomass trends. Moths (Lepidoptera) provide particularly good opportunities to study trends and drivers of biomass change at large spatial and temporal scales, given the existence of long-term abundance datasets. However, data on the body masses of moths are required for these analyses, but such data do not currently exist.To address this data gap, we collected empirical data in 2018 on the forewing length and dry mass of field-sampled moths, and used these to train and test a statistical model that predicts the body mass of moth species from their forewing lengths (with refined parameters for Crambidae, Erebidae, Geometridae and Noctuidae).Modeled biomass was positively correlated, with high explanatory power, with measured biomass of moth species (R 2 = 0.886 ± 0.0006, across 10,000 bootstrapped replicates) and of mixed-species samples of moths (R 2 = 0.873 ± 0.0003), showing that it is possible to predict biomass to an informative level of accuracy, and prediction error was smaller with larger sample sizes.Our model allows biomass to be estimated for historical moth abundance datasets, and so our approach will create opportunities to investigate trends and drivers of insect biomass change over long timescales and broad geographic regions.
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Affiliation(s)
| | - Chris D. Thomas
- Department of BiologyUniversity of YorkYorkUK
- Leverhulme Centre for Anthropocene BiodiversityUniversity of YorkYorkUK
| | | | - Jane K. Hill
- Department of BiologyUniversity of YorkYorkUK
- Leverhulme Centre for Anthropocene BiodiversityUniversity of YorkYorkUK
| | | | - Callum J. Macgregor
- Department of BiologyUniversity of YorkYorkUK
- Leverhulme Centre for Anthropocene BiodiversityUniversity of YorkYorkUK
- Energy and Environment InstituteUniversity of HullHullUK
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Walton RE, Sayer CD, Bennion H, Axmacher JC. Nocturnal pollinators strongly contribute to pollen transport of wild flowers in an agricultural landscape. Biol Lett 2020; 16:20190877. [PMID: 32396782 PMCID: PMC7280044 DOI: 10.1098/rsbl.2019.0877] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 04/08/2020] [Indexed: 11/12/2022] Open
Abstract
Dramatic declines in diurnal pollinators have created great scientific interest in plant-pollinator relationships and associated pollination services. Existing literature, however, is generally focused on diurnal pollinating insect taxa, especially on Apidae (Hymenoptera) and Syrphidae (Diptera) pollinators, while nocturnal macro-moths that comprise extremely species-rich flower-visiting families have been largely neglected. Here, we report that in agricultural landscapes, macro-moths can provide unique, highly complex pollen transport links, making them vital components of overall wild plant-pollinator networks in agro-ecosystems. Pollen transport occurred more frequently on the moths' ventral thorax rather than on their mouthparts that have been traditionally targeted for pollen swabbing. Pollen transport loads suggest that nocturnal moths contribute key pollination services for several wild plant families in agricultural landscapes, in addition to providing functional resilience to diurnal networks. Severe declines in richness and abundance of settling moth populations highlight the urgent need to include them in future management and conservation strategies within agricultural landscapes.
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Affiliation(s)
- Richard E. Walton
- Environmental Change Research Centre, Department of Geography, University College London, London WC1E 6BT, UK
| | - Carl D. Sayer
- Environmental Change Research Centre, Department of Geography, University College London, London WC1E 6BT, UK
| | - Helen Bennion
- Environmental Change Research Centre, Department of Geography, University College London, London WC1E 6BT, UK
| | - Jan C. Axmacher
- Environmental Change Research Centre, Department of Geography, University College London, London WC1E 6BT, UK
- Faculty of Environmental and Forest Sciences, Agricultural University of Iceland, Keldnaholt, 112 Reykjavík, Iceland
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Affiliation(s)
- Maria Dornelas
- Centre for Biological Diversity, School of Biology, University of St Andrews, St Andrews KY16 9TH, Scotland, UK.
| | - Gergana N Daskalova
- School of GeoSciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3FF, Scotland, UK.
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Nutrient dilution and climate cycles underlie declines in a dominant insect herbivore. Proc Natl Acad Sci U S A 2020; 117:7271-7275. [PMID: 32152101 DOI: 10.1073/pnas.1920012117] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Evidence for global insect declines mounts, increasing our need to understand underlying mechanisms. We test the nutrient dilution (ND) hypothesis-the decreasing concentration of essential dietary minerals with increasing plant productivity-that particularly targets insect herbivores. Nutrient dilution can result from increased plant biomass due to climate or CO2 enrichment. Additionally, when considering long-term trends driven by climate, one must account for large-scale oscillations including El Niño Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), and Pacific Decadal Oscillation (PDO). We combine long-term datasets of grasshopper abundance, climate, plant biomass, and end-of-season foliar elemental content to examine potential drivers of abundance cycles and trends of this dominant herbivore. Annual grasshopper abundances in 16- and 22-y time series from a Kansas prairie revealed both 5-y cycles and declines of 2.1-2.7%/y. Climate cycle indices of spring ENSO, summer NAO, and winter or spring PDO accounted for 40-54% of the variation in grasshopper abundance, mediated by effects of weather and host plants. Consistent with ND, grass biomass doubled and foliar concentrations of N, P, K, and Na-nutrients which limit grasshopper abundance-declined over the same period. The decline in plant nutrients accounted for 25% of the variation in grasshopper abundance over two decades. Thus a warming, wetter, more CO2-enriched world will likely contribute to declines in insect herbivores by depleting nutrients from their already nutrient-poor diet. Unlike other potential drivers of insect declines-habitat loss, light and chemical pollution-ND may be widespread in remaining natural areas.
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Bell JR, Blumgart D, Shortall CR. Are insects declining and at what rate? An analysis of standardised, systematic catches of aphid and moth abundances across Great Britain. INSECT CONSERVATION AND DIVERSITY 2020; 13:115-126. [PMID: 32215052 PMCID: PMC7079554 DOI: 10.1111/icad.12412] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/11/2020] [Accepted: 02/12/2020] [Indexed: 05/08/2023]
Abstract
Although we have known anecdotally that insects have been declining in Great Britain for more than 100 years, insect declines have only been statistically estimated over the last 20 years. Estimation of the rate of those declines is still hotly debated, fuelled by a lack of standardised, systematically collected data.More than 24 million individual moths and aphids collected from 112 light traps and 25 12.2 m suction-traps, respectively, were analysed using mixed models. Our objective was to estimate the long-term trends in both groups based on annual totals recorded every year between 1969 and 2016.The models showed that two paradigms existed: Over 47 years, long-term linear trends showed that moths had declined significantly by -31%, but short-term trends indicated that there were periods of significant decline and recovery in most decades since the 1960s. Conversely, despite aphid annual totals fluctuating widely, this group was in a steady state over the long-term, with a non-significant decline of -7.6%. Sensitivity analysis revealed that moth trends were not driven by a group of abundant species, but the sign of the overall aphid trends may have been driven by three of the most abundant species.The spatial extent of moth trends suggests that they are extremely heterogeneous. Uniquely, moth declines were different among several habitat types, with robust significant declines found in coastal, urban and woodland habitats, but notably not in agricultural, parkland and scrubland habitats. Conversely, aphid trends showed spatial synchrony extending to 338 km, albeit with local variation.
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Affiliation(s)
- James R. Bell
- Rothamsted Insect Survey, Rothamsted Research, West CommonHarpendenUK
| | - Dan Blumgart
- Rothamsted Insect Survey, Rothamsted Research, West CommonHarpendenUK
| | - Chris R. Shortall
- Rothamsted Insect Survey, Rothamsted Research, West CommonHarpendenUK
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Mancini F, Woodcock BA, Redhead J, Spurgeon D, Jarvis S, Pywell RF, Shore R, Johnson A, Isaac N. Detecting landscape scale consequences of insecticide use on invertebrate communities. ADV ECOL RES 2020. [DOI: 10.1016/bs.aecr.2020.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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