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Bauer S, Tielens EK, Haest B. Monitoring aerial insect biodiversity: a radar perspective. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230113. [PMID: 38705181 PMCID: PMC11070259 DOI: 10.1098/rstb.2023.0113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Accepted: 03/21/2024] [Indexed: 05/07/2024] Open
Abstract
In the current biodiversity crisis, populations of many species have alarmingly declined, and insects are no exception to this general trend. Biodiversity monitoring has become an essential asset to detect biodiversity change but remains patchy and challenging for organisms that are small, inconspicuous or make (nocturnal) long-distance movements. Radars are powerful remote-sensing tools that can provide detailed information on intensity, timing, altitude and spatial scale of aerial movements and might therefore be particularly suited for monitoring aerial insects and their movements. Importantly, they can contribute to several essential biodiversity variables (EBVs) within a harmonized observation system. We review existing research using small-scale biological and weather surveillance radars for insect monitoring and outline how the derived measures and quantities can contribute to the EBVs 'species population', 'species traits', 'community composition' and 'ecosystem function'. Furthermore, we synthesize how ongoing and future methodological, analytical and technological advancements will greatly expand the use of radar for insect biodiversity monitoring and beyond. Owing to their long-term and regional-to-large-scale deployment, radar-based approaches can be a powerful asset in the biodiversity monitoring toolbox whose potential has yet to be fully tapped. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'.
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Affiliation(s)
- Silke Bauer
- Swiss Federal Institute for Forest, Snow and Landscape Research, 8903 Birmensdorf, Switzerland
- Swiss Ornithological Institute, Sempach, LU 6204, Switzerland
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, Noord-Holland, The Netherlands
- Department of Environmental System Science, Federal Institute of Technology (ETH), 8092 Zürich, Switzerland
| | - Elske K. Tielens
- School of Biological Sciences, University of Oklahoma, Norman, OK 73019-0390, USA
| | - Birgen Haest
- Swiss Ornithological Institute, Sempach, LU 6204, Switzerland
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Drake VA, Hao Z, Wang H. Monitoring insect numbers and biodiversity with a vertical-beam entomological radar. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230117. [PMID: 38705193 PMCID: PMC11070261 DOI: 10.1098/rstb.2023.0117] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 02/06/2024] [Indexed: 05/07/2024] Open
Abstract
Concerns about perceived widespread declines in insect numbers have led to recognition of a requirement for long-term monitoring of insect biodiversity. Here we examine whether an existing, radar-based, insect monitoring system developed for research on insect migration could be adapted to this role. The radar detects individual larger (greater than 10 mg) insects flying at heights of 150-2550 m and estimates their size and mass. It operates automatically and almost continuously through both day and night. Accumulation of data over a 'half-month' (approx. 15 days) averages out weather effects and broadens the source area of the wind-borne observation sample. Insect counts are scaled or interpolated to compensate for missed observations; adjustment for variation of detectability with range and insect size is also possible. Size distributions for individual days and nights exhibit distinct peaks, representing different insect types, and Simpson and Shannon-Wiener indices of biodiversity are calculated from these. Half-month count, biomass and index statistics exhibit variations associated with the annual cycle and year to year changes that can be attributed to drought and periods of high rainfall. While species-based biodiversity measures cannot be provided, the radar's capacity to estimate insect biomass over a wide area indicates utility for tracking insect population sizes. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'.
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Affiliation(s)
- V. Alistair Drake
- School of Science, The University of New South Wales, Canberra, ACT 2610, Australia
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, Australia
| | - Zhenhua Hao
- School of Science, The University of New South Wales, Canberra, ACT 2610, Australia
- Australian Bureau of Agricultural and Resource Economics and Science, Australian Government, Canberra, ACT 2601, Australia
| | - Haikou Wang
- Australian Plague Locust Commission, Department of Agriculture, Fisheries and Forestry, Australian Government, Canberra, ACT 2601, Australia
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Saha T, Genoud AP, Park JH, Thomas BP. Temperature Dependency of Insect's Wingbeat Frequencies: An Empirical Approach to Temperature Correction. INSECTS 2024; 15:342. [PMID: 38786898 PMCID: PMC11121811 DOI: 10.3390/insects15050342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/06/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024]
Abstract
This study examines the relationship between the wingbeat frequency of flying insects and ambient temperature, leveraging data from over 302,000 insect observations obtained using a near-infrared optical sensor during an eight-month field experiment. By measuring the wingbeat frequency as well as wing and body optical cross-sections of each insect in conjunction with the ambient temperature, we identified five clusters of insects and analyzed how their average wingbeat frequencies evolved over temperatures ranging from 10 °C to 38 °C. Our findings reveal a positive correlation between temperature and wingbeat frequency, with a more pronounced increase observed at higher wingbeat frequencies. Frequencies increased on average by 2.02 Hz/°C at 50 Hz, and up to 9.63 Hz/°C at 525 Hz, and a general model is proposed. This model offers a valuable tool for correcting wingbeat frequencies with temperature, enhancing the accuracy of insect clustering by optical and acoustic sensors. While this approach does not account for species-specific responses to temperature changes, our research provides a general insight, based on all species present during the field experiment, into the intricate dynamics of insect flight behavior in relation to environmental factors.
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Affiliation(s)
- Topu Saha
- Department of Physics, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA;
| | - Adrien P. Genoud
- Institut Lumière Matière, UMR 5306, Université Claude Bernard Lyon 1, CNRS, F-69100 Villeurbanne, France;
| | - Jung H. Park
- Department of Data Science, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA;
| | - Benjamin P. Thomas
- Department of Physics, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA;
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Wallace JRA, Dreyer D, Reber TMJ, Khaldy L, Mathews-Hunter B, Green K, Zeil J, Warrant E. Camera-based automated monitoring of flying insects in the wild (Camfi). II. flight behaviour and long-term population monitoring of migratory Bogong moths in Alpine Australia. FRONTIERS IN INSECT SCIENCE 2023; 3:1230501. [PMID: 38469465 PMCID: PMC10926487 DOI: 10.3389/finsc.2023.1230501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 08/21/2023] [Indexed: 03/13/2024]
Abstract
Introduction The Bogong moth Agrotis infusa is well known for its remarkable annual round-trip migration from its breeding grounds across eastern and southern Australia to its aestivation sites in the Australian Alps, to which it provides an important annual influx of nutrients. Over recent years, we have benefited from a growing understanding of the navigational abilities of the Bogong moth. Meanwhile, the population of Bogong moths has been shrinking. Recently, the ecologically and culturally important Bogong moth was listed as endangered by the IUCN Red List, and the establishment of a program for long-term monitoring of its population has been identified as critical for its conservation. Methods Here, we present the results of two years of monitoring of the Bogong moth population in the Australian Alps using recently developed methods for automated wildlife-camera monitoring of flying insects, named Camfi. While in the Alps, some moths emerge from the caves in the evening to undertake seemingly random flights, filling the air with densities in the dozens per cubic metre. The purpose of these flights is unknown, but they may serve an important role in Bogong moth navigation. Results We found that these evening flights occur throughout summer and are modulated by daily weather factors. We present a simple heuristic model of the arrival to and departure from aestivation sites by Bogong moths, and confirm results obtained from fox-scat surveys which found that aestivating Bogong moths occupy higher elevations as the summer progresses. Moreover, by placing cameras along two elevational transects below the summit of Mt. Kosciuszko, we found that evening flights were not random, but were systematically oriented in directions relative to the azimuth of the summit of the mountain. Finally, we present the first recorded observations of the impact of bushfire smoke on aestivating Bogong moths - a dramatic reduction in the size of a cluster of aestivating Bogong moths during the fire, and evidence of a large departure from the fire-affected area the day after the fire. Discussion Our results highlight the challenges of monitoring Bogong moths in the wild and support the continued use of automated camera-based methods for that purpose.
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Affiliation(s)
- Jesse Rudolf Amenuvegbe Wallace
- Research School of Biology, The Australian National University, Canberra, ACT, Australia
- National Collections & Marine Infrastructure, CSIRO, Parkville, VIC, Australia
| | - David Dreyer
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | | | - Lana Khaldy
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | | | - Ken Green
- College of Asia and the Pacific, The Australian National University, Canberra, ACT, Australia
| | - Jochen Zeil
- Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Eric Warrant
- Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
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Wainwright CE, Volponi SN, Stepanian PM, Reynolds DR, Richter DH. Using cloud radar to investigate the effect of rainfall on migratory insect flight. Methods Ecol Evol 2022. [DOI: 10.1111/2041-210x.14023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Charlotte E. Wainwright
- Department of Civil & Environmental Engineering & Earth Sciences University of Notre Dame Notre Dame Indiana USA
| | - Sabrina N. Volponi
- Department of Civil & Environmental Engineering & Earth Sciences University of Notre Dame Notre Dame Indiana USA
| | - Phillip M. Stepanian
- Department of Civil & Environmental Engineering & Earth Sciences University of Notre Dame Notre Dame Indiana USA
| | - Don R. Reynolds
- Natural Resources Institute University of Greenwich Kent UK
- Rothamsted Research Harpenden UK
| | - David H. Richter
- Department of Civil & Environmental Engineering & Earth Sciences University of Notre Dame Notre Dame Indiana USA
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Lukach M, Dally T, Evans W, Hassall C, Duncan EJ, Bennett L, Addison FI, Kunin WE, Chapman JW, Neely RR. The development of an unsupervised hierarchical clustering analysis of dual-polarization weather surveillance radar observations to assess nocturnal insect abundance and diversity. REMOTE SENSING IN ECOLOGY AND CONSERVATION 2022; 8:698-716. [PMID: 36588588 PMCID: PMC9790603 DOI: 10.1002/rse2.270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 02/22/2022] [Accepted: 04/05/2022] [Indexed: 06/17/2023]
Abstract
Contemporary analyses of insect population trends are based, for the most part, on a large body of heterogeneous and short-term datasets of diurnal species that are representative of limited spatial domains. This makes monitoring changes in insect biomass and biodiversity difficult. What is needed is a method for monitoring that provides a consistent, high-resolution picture of insect populations through time over large areas during day and night. Here, we explore the use of X-band weather surveillance radar (WSR) for the study of local insect populations using a high-quality, multi-week time series of nocturnal moth light trapping data. Specifically, we test the hypotheses that (i) unsupervised data-driven classification algorithms can differentiate meteorological and biological phenomena, (ii) the diversity of the classes of bioscatterers are quantitatively related to the diversity of insects as measured on the ground and (iii) insect abundance measured at ground level can be predicted quantitatively based on dual-polarization Doppler WSR variables. Adapting the quasi-vertical profile analysis method and data clustering techniques developed for the analysis of hydrometeors, we demonstrate that our bioscatterer classification algorithm successfully differentiates bioscatterers from hydrometeors over a large spatial scale and at high temporal resolutions. Furthermore, our results also show a clear relationship between biological and meteorological scatterers and a link between the abundance and diversity of radar-based bioscatterer clusters and that of nocturnal aerial insects. Thus, we demonstrate the potential utility of this approach for landscape scale monitoring of biodiversity.
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Affiliation(s)
- Maryna Lukach
- National Centre for Atmospheric Science and the School of Earth and EnvironmentUniversity of Leeds71‐75 Clarendon Rd, WoodhouseLeedsLS2 9PHUK
| | - Thomas Dally
- School of Biology, Faculty of Biological SciencesUniversity of LeedsWoodhouse LaneLeedsLS2 9JTUK
| | - William Evans
- National Centre for Atmospheric Science and the School of Earth and EnvironmentUniversity of Leeds71‐75 Clarendon Rd, WoodhouseLeedsLS2 9PHUK
- School of Biology, Faculty of Biological SciencesUniversity of LeedsWoodhouse LaneLeedsLS2 9JTUK
| | - Christopher Hassall
- School of Biology, Faculty of Biological SciencesUniversity of LeedsWoodhouse LaneLeedsLS2 9JTUK
| | - Elizabeth J. Duncan
- School of Biology, Faculty of Biological SciencesUniversity of LeedsWoodhouse LaneLeedsLS2 9JTUK
| | - Lindsay Bennett
- National Centre for Atmospheric Science and the School of Earth and EnvironmentUniversity of Leeds71‐75 Clarendon Rd, WoodhouseLeedsLS2 9PHUK
| | - Freya I. Addison
- National Centre for Atmospheric Science and the School of Earth and EnvironmentUniversity of Leeds71‐75 Clarendon Rd, WoodhouseLeedsLS2 9PHUK
| | - William E. Kunin
- School of Biology, Faculty of Biological SciencesUniversity of LeedsWoodhouse LaneLeedsLS2 9JTUK
| | - Jason W. Chapman
- Centre for Ecology and Conservation, and Environment and Sustainability InstituteUniversity of ExeterPenryn, CornwallTR10 9FEUK
- Department of Entomology, College of Plant ProtectionNanjing Agricultural UniversityNanjing210095People's Republic of China
| | - Ryan R. Neely
- National Centre for Atmospheric Science and the School of Earth and EnvironmentUniversity of Leeds71‐75 Clarendon Rd, WoodhouseLeedsLS2 9PHUK
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