Insect wing design: evolution and biomechanics

Lead Research Organisation: University of Oxford
Department Name: Zoology

Abstract

Insects are the most diverse order of animals on earth and flight may be the key to this success. However, despite hundreds of millions of years of evolution, insect wings have not converged on a single optimal shape. Instead, there is an extraordinary range of wing morphologies visible in the world today (and even more fossilized), yet fundamentally, they all perform the same task - to enable flight. This led me to ask 'why is there no single wing shape that is best-suited to flapping flight?'The answer may well lie in assorted locally optimal solutions, specifically adapted to the tasks each insect undertakes during its life. The mission-profile of flight is unique for each insect species and so the selection pressures on wing morphology and kinematics is also species specific. A dragonfly that catches its prey on the wing and engages in aerial combat against rivals must be fast and manoeuvrable. Contrast this with the death's-head hawkmoth, migrating across Europe raiding bees' nests. They must be highly efficient since energy is at a premium during migration, but also robust enough to withstand attacks from bees when in their honey-stores. Understanding the morphologies of over a million described flying insect species is unfeasible, yet trends run through them which are exciting for aerodynamic engineering because they show solutions to specific requirements that have been tried, tested, and proven to succeed.My research seeks to understand how and why insect wing shapes have such variation despite intense selective pressure for aerodynamic performance, and why morphologies change when transitioning between ecological niches. The best way to examine this is to look at examples of convergent evolution, species which have similar ecology and morphology, yet originate from disparate taxonomic branches. Selecting species which are quite unrelated from one another allows discrimination of the aspects of wing shape which are part of design optimisation as opposed to those which are simply due to their historical starting point. My experiment therefore utilizes a comparative approach to evaluate representative species from across the class.In Track 1 of my research programme, a Postdoc will measure the aerodynamic output of flying insects directly, because it is essential to know how fast and in which direction the air is moving around the wings and in the wake. Flow velocities will be calculated around insects tethered in a wind tunnel by seeding the air with a light fog, and illuminating the particles with pulsing laser light. This technique is called Digital Particle Image Velocimetry and is the technique of choice for engineers studying complex flows. Recently, I successfully applied the technique to flying insects despite their small size and high wingbeat frequencies.Insects have no musculature in their wings. All the deforming complexities of the flapping cycle are controlled either actively by muscles at the wing hinge, or passively by inertial and aerodynamic forces on the wing architecture. The aerodynamic output is a result of wing motion so it is vital to know how the wing shape changes during flapping. In Track 2 of my research, a PhD student will record the kinematics of individuals from the same representative insects. The student will test predictions about the role of wing shape in ecology, by artificially selecting strains of fruit fly for alternate morphologies (e.g. more slender wings) and characterising the new morphs' flight performance. Simultaneously, the student will validate their results, by selecting strains based upon flight performance, and measuring the resulting modification in wing morphology.The output from these two tracks will be: 1) an explanation for the diversity of insect wing shapes from the perspective of biomechanical adaptation; 2) detailed kinematic data for Computational Fluid Dynamics studies; 3) clear design guidelines for engineers constructing insect-sized vehicles.

Publications

10 25 50

Related Projects

Project Reference Relationship Related To Start End Award Value
EP/H004025/1 01/10/2009 30/06/2013 £1,183,660
EP/H004025/2 Transfer EP/H004025/1 01/07/2013 31/03/2015 £363,412
 
Description Our main findings concern the inter-related elements of wing surface shape, wing stroke kinematics and aerodynamics of insects in flight. To take a few examples, we have shown how detail of the deforming wing of locust wings give rise to unusual aerodynamics and substantial efficiency benefits (Science). We have shown how flight efficiency in insects changes with wing planform (Proc. Roy. Soc. B), or flight style (J. Roy. Soc. Interface, x2). We have tested the applicability of these effects using robotic demonstrators (Interface Focus, Bioinspiration and Biomimetics), computational methods (J Fluid Mech), and by using recent genetic techniques (RNA interference) to artificially modify wing shape in fruit flies (Nature Comms). We have also expanded the suite of unorthodox aerodynamic mechanisms used by insects by observing two new ways in which small fliers generate lift using mosquitoes as a model (Nature). In each case, data were presented in the context of how these factors contributed to overall flight performance. In total, we have collected flow field data from >25 species and morphological and flight performance data from over 50 species. We have data from representatives of the Hymenoptera, Orthoptera, Coleoptera, Odonata, Diptera and Lepidoptera. I.e. from most of the major insect orders. We have representatives from all the guilds of flight specialities we chose to investigate (aerial predators, load carriers and migrants), from orders with synchronous as well as asynchronous muscles, and from overlapping size ranges.

Alongside these primary objectives, the methods we used have been applied outside the original scope of the work to investigate insects sensing for flight control (J. Roy Soc. Interface), tendon regenerative properties (J Roy. Soc. Interface), the health of newly fertilised eggs and their suitability for assisted reproduction (Nature Comms.), and even the explosive ejection of seeds from plants (Cell).
Exploitation Route Through our fundamental research we have opened new avenues for analysis within the academic sector (in particular, these methods could be picked up for flying vertebrates and aquatic organisms) and technological development in the aerospace sector.

The applicability of our research within the wider industrial sector has been recognised with further funding through a BBSRC FLIP grant in association with SME, LaVision, who develop the fluid diagnostic tools we use, and they have invested substantially in our continuing partnership on the back of the work produced by this grant.
Sectors Aerospace, Defence and Marine,Environment,Leisure Activities, including Sports, Recreation and Tourism,Manufacturing, including Industrial Biotechology,Security and Diplomacy,Transport

 
Description This fellowship grant has had significant impact in a number of fields. We now have a better understanding of the world around us, particularly the functional significance of the diversity of evolved wing shapes in insects. We have information derived from those findings that can be (and have been) used to develop new flight technologies. The work has been published in top multidisciplinary journals (Science, Nature, Cell, Nature Communications, Phil. Trans. Roy. Soc. B) as well as specialist journals for biology (Evolutionary Biology), engineering (Journal of Fluid Mechanics) and the interface of those fields (Journal of the Royal Society: Interface). Our discoveries have often captured public attention and have been reported online, in print, and in award winning television across the world (e.g. David Attenborough and Brian Cox documentaries on Sky, BBC, Discovery Channel). The work has also interested a number of government agencies and SMEs, often leading to further funding for related work in the fields of detailed flow and surface measurements, or application to novel aerial systems. We have delivered results directly to the bio-inspired Unmanned Air Systems (UAS) community at NATO technical panel meetings, helping to shape the research effort policy in this area, and also the Ministry of Defence's Centre of Excellence in Bio-inspired Technologies (multiple meetings with government, and SME representatives). The impact of our research is of great interest to UAS manufacturers. The Ministry of Defence have supported related work in the form of two PhD positions through DSTL directly and an RCUK ICASE studentship. This continued to research grants developing our mosquito work (Nature) in the context of UAS propulsion as well as guidance, navigation and control. This, in turn, has led to concept development funding with Oxford University spin-out company, Animal Dynamics. The applicability of our research within the wider industrial sector has been recognised with further funding through a BBSRC FLIP grant in association with SME, LaVision, who develop the fluid diagnostic tools we use, and they have invested substantially in our continuing partnership on the back of the work produced by this grant. During the grant period, postdoctoral staff in the lab have moved on either to further postdoc positions or to tenure-track positions in other institutions.
First Year Of Impact 2010
Sector Aerospace, Defence and Marine,Government, Democracy and Justice,Security and Diplomacy,Transport
Impact Types Cultural,Societal,Economic

 
Description ASUR Phase 1 Addition: Insect-inspired sense and avoid strategies: surface detection in the dark using induced flow field modulation
Amount £13,430 (GBP)
Organisation Defence Science & Technology Laboratory (DSTL) 
Sector Public
Country United Kingdom
Start 09/2015 
End 12/2015
 
Description ASUR Phase 1: Insect-inspired sense and avoid strategies: surface detection in the dark using induced flow field modulation
Amount £44,310 (GBP)
Organisation Defence Science & Technology Laboratory (DSTL) 
Sector Public
Country United Kingdom
Start 04/2015 
End 09/2015
 
Description ASUR Phase 2: Insect-inspired sense and avoid strategies: surface detection in the dark using induced flow field modulation
Amount £199,275 (GBP)
Organisation Defence Science & Technology Laboratory (DSTL) 
Sector Public
Country United Kingdom
Start 12/2015 
End 04/2017
 
Description BBSRC responsive mode
Amount £369,459 (GBP)
Funding ID BB/J001244/1 and subsequently BB/J001244/2 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 10/2012 
End 08/2015
 
Description Concept Development Partnership Fund
Amount £100,000 (GBP)
Organisation Royal Veterinary College (RVC) 
Sector Academic/University
Country United Kingdom
Start 04/2017 
End 03/2018
 
Description DSTL National UK PhD Programme: Distributed flow sensing and load sensing in insect flight, with applications to the control of highly manoeuvrable unmanned air systems.
Amount £170,493 (GBP)
Organisation Defence Science & Technology Laboratory (DSTL) 
Sector Public
Country United Kingdom
Start 10/2012 
End 09/2016
 
Description EPSRC ICASE studentship with DSTL: Insect wing design and its application to bio-inspired Unmanned Air Systems
Amount £91,531 (GBP)
Organisation Defence Science & Technology Laboratory (DSTL) 
Sector Public
Country United Kingdom
Start 10/2013 
End 03/2017
 
Description EPSRC New Directions for Research Leaders
Amount £234,448 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 05/2012 
End 03/2014
 
Description EPSRC Small Equipment Portfolio
Amount £10,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 12/2012 
End 01/2013
 
Description Multifunctional materials and structures. Avian-inspired Multifunctional Morphing Air Vehicles: Underpinning Biological Research
Amount $846,127 (USD)
Organisation European Office of Aerospace Research & Development (EOARD) 
Sector Public
Country United Kingdom
Start 10/2015 
End 09/2020
 
Title Research Tool: Portable wind and water tunnels. 
Description Three fluid flow tunnels for biological research based at the Royal Veterinary College. 1. Portable flow conditioning wind tunnel (0.25m x 0.25m) 2. 40mm diameter pulsing water tunnel for haemodynamics and hydrodynamics experiments. 3. Low-speed, low-turbulence insect-scale wind tunnel (0.5m x 0.5m) 
Type Of Material Improvements to research infrastructure 
Year Produced 2014 
Provided To Others? Yes  
Impact Collection of three data sets as part of the FLIP project deliverables. Colelction of data sets for BBSRC- and EPSRC- funded research projects. Loan to the BBC for documentary. Use in Discovery Channel documentary. 
 
Description LaVision tomographic PIV 
Organisation LaVision GmbH
Country Germany 
Sector Private 
PI Contribution Provided expertise, staff time, intellectual input and equipment resources, initially on an ad hoc basis, for a series of experiments that introduced high-speed, volumetric Particle Image Velocimetry (tomo-PIV) to animal flight.
Collaborator Contribution Provided technical expertise, human resources, software, processing power, and intellectual input to capture and process tomo-PIV data, initially on an ad hoc basis.
Impact The collaboration outputs were: 1. journal publications (Journal of the Royal Society: Interface), 2. formal funding (BBSRC FLIP grant), 3. promotional material for LaVision, 4. accessible visualised data for public (e.g. science festivals, TV documentaries), 5. industry/government engagement (e.g. Ministry of Defence, Royal Aeronautical Association Light Aircraft Design conference). 6. A Technical Application Note for LaVision hardware and software.
Start Year 2009
 
Description Aircraft design workshop 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Presentation plus panel Q&A for The Royal Aeronautical Society London. Approx. 60 attendees plus further reach via newsletter on the topic of Bioinspiration for Light Aircraft Design. Much discussion of data collection and analysis methods followed with industry and some academics. Photographs and data exchanged for developing promotional material for Swift Aircraft.
Year(s) Of Engagement Activity 2015
URL https://www.aerosociety.com/Assets/Docs/Events/790/790_Speaker_Bios.pdf
 
Description BBSRC Great British Bioscience festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact The Great British Bioscience Festival took place on 14-16 November 2014, attracting over 6,500 visitors.

The festival provided an excellent opportunity to showcase cutting-edge bioscience to the community of Bethnal Green and beyond, it generated support for bioscience and developed researchers' experience and confidence in public engagement.

The Great British Bioscience Festival was a bustling, energetic event that was very much
appreciated by its local audience.
Its location in Bethnal Green was effective in engaging with a new audience in an area
with high levels of social and economic deprivation and the event revealed a considerable
appetite for this type of activity.
Visitors left feeling engaged and enthused by bioscience, with new knowledge and a
greater understanding of science and how science works. They also left with a greater
awareness of BBSRC.
Researchers exhibiting at the festival reported an uplifting experience that improved their
communication skills, made them more interested in public engagement and reinvigorated
them regarding the value of their own work.
The Great British Bioscience Festival has shown a clear desire for high quality engagement
with contemporary bioscience and researchers for groups who are typically underserved by
this type of opportunity. These groups are often seen as a difficult to engage with, but the
festival has demonstrated a successful way of doing so.
Both researchers and visitors would like to be offered more frequent opportunities of this
kind.
As one visitor put it:
"3 days in 20 years is not enough, we want to learn more.
Thank you!
Alicia"
Year(s) Of Engagement Activity 2014
URL http://www.bbsrc.ac.uk/engagement/exhibitions/gb-bioscience-festival/
 
Description Consultancy for BBC TV documentary: Invisible Nature: Flight revealed 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Consultancy about beetles on a programme about animal flight. Used our wind tunnels to generated content for the title sequence of the series.
Year(s) Of Engagement Activity 2016
 
Description Gravity Fields Science and Arts Festival 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Public lecture as part of the Gravity Fields Science and Arts Festival in honour of Isaac Newton. A full house of approx. 85 members of the public attended in Newton's hometown of Grantham, Lincolnshire. Many, wide-ranging, general interest questions afterwards about bird and insect flight. The event was trailed on tv and followed up with articles and letters in local newspapers.
Year(s) Of Engagement Activity 2016
URL https://www.gravityfields.co.uk/index.aspx?articleid=11217
 
Description Lecture and panel Q&A (Royal Aeronautical Society) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Lecture and panel discussion/Q&A at the Royal Aeronautical Society (London) as part of a day focussing on light aircraft design.
Year(s) Of Engagement Activity 2015
 
Description Public lecture at the Cheltenham Science Festival 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact talk sparked questions and discussion afterwards.

Stimulated thinking in broad audience. Enthusiasm for animal locomotion and bio-inspired design.
Year(s) Of Engagement Activity 2013
 
Description Sky documentary (Conquest of the Skies) 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Scientific consultancy the documentary film making and dialogue.

This Attenborough documentary international success and won a BAFTA in 2015.
Year(s) Of Engagement Activity 2014
URL http://www.sky.com/tv/show/david-attenboroughs-conquest-of-the-skies
 
Description Update 3: Extension of Fundamental Flow Physics to Practical Micro Air Vehicle Aerodynamics (AVT-202)3 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? Yes
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Extensive discussions of data and plans for future international collaborative research.

Decision making on future directions.
Year(s) Of Engagement Activity 2013