ABSTRACT BOOK SEB BRIGHTON 2016 4–7 July, 2016 BRIGHTON CENTRE,UK SEBIOLOGY.ORG #SEBAMM SUN, SEA & SCIENCE SOCIETY FOR EXPERIMENTAL BIOLOGY ABSTRACTS ANIMAL BIOLOGY 2 ANNUAL MAIN MEETING BRIGHTON 2016 ANIMAL ABSTRACTS 44 A1 DEVELOPMENTAL BIOMECHANICS OF MOTOR SKILLS ORGANISED BY:PROF JOHAN VAN LEEUWEN (WAGENINGEN UNIVERSITY, NETHERLANDS) & PROF PETER AERTS (UNIVERSITY OF ANTWERP, BELGIUM) i n loca l be nd i ng powe r a s t he fi sh g rows. We developed a combi ned A1.1 ACQUIRED VERSUS INNATE experimental and computational approach for reconstructing time- PREY CAPTURING SKILLS IN SUPER- resolved bending moment distributions from high-speed videos of f ree -sw i m m i ng la r vae (2-12 dpf ). Fi rst, we recon st r uc t t he t h ree - PRECOCIAL LIVE-BEARING FISH dimensional position, orientation and body curvature from these i mages. We feed t hese recon st r uc t ion s i nto a computat iona l flu id- TUESDAY 5 JULY, 2016 13:45 dynamics solver in order to calculate the flow field and the fluid forces a long t he fi sh’s body. Fi na l ly, we combi ne t he mot ion of t he long it ud i na l body a x i s a nd t he e x te r na l flu id forces a s i nput for a n MARTIN LANKHEET (WAGENINGEN UNIVERSITY, NETHERLANDS) opt i m i zat ion procedu re to ca lc u late t he best fit t i ng t i me - depe nde nt Live-bearing fish start hunting for mobile prey within hours after bending moment distribution. The dynamics of these bending birth, an example of extreme precociality. Because prenatal, in moments provide novel insight in the developmental mechanics of utero, development of this behaviour is constrained by the lack of sw i m m i ng ac ross t he fi rst stages of zebra fi sh . free-swimming sensory-motor interactions, immediate success after birth depends on innate, evolutionary acquired patterns. O pt i ma l pe r for ma nce howeve r requ i res fle x ible adju st me nt to a n unpredictable environment. To distinguish innate from postnatally A1.3 HOW TAIL-BEAT FREQUENCY AND acqu i red pat te r n s we a na ly zed ove r 20 0 0 prey capt u re event s for 28 BODY CURVATURE AFFECT SWIMMING Metallic livebearers (Girardinus metallicus; Poeciliidae), during their first three days after birth. We show that the use of synchronous PERFORMANCE IN LARVAL ZEBRAFISH pec tora l fi n beat s for fi na l accele rat ion a nd i ngest ion i s t r u ly i nnate. It allows for direct control while avoiding head yaw, supporting TUESDAY 5 JULY, 2016 14:30 immediate success. Rapid development of eye movements and body curvatures, however, show that eye-tail coordination requires GEN LI (CHIBA UNIVERISTY, JAPAN), ULRIKE K MÜLLER postnatal learning and calibration. The combination of innate motor (CALIFORNIA STATE UNIVERSITY FRESNO, UNITED STATES), programs and rapid, postnatal development reveal how super- HAO LIU (CHIBA UNIVERISTY, JAPAN), JOHAN L VAN LEEUWEN precocial animals optimize survival into adulthood. (WAGENINGEN UNIVERSITY, NETHERLANDS) [email protected] A1.2 BENDING MOMENT DYNAMICS Small undulatory swimmers such as larval zebrafish operate in DURING SWIMMING OF DEVELOPING t he i nte r med iate Rey nold s reg i me a nd e x pe r ience relat ively h ig h d rag du r i ng c ycl ic sw i m m i ng. E x per i menta l obser vat ions ( J. R . ZEBRAFISH LARVAE Soc. I nte r face 12: 20150 479) de mon st rated (a) t hat la r va l zebra fi sh tend to increase both tail-beat frequency and amplitude with TUESDAY 5 JULY, 2016 14:15 swimming speed and (b) a negative power relationship between St rou ha l nu mbe r a nd Rey nold s nu mbe r du r i ng c yc l ic sw i m m i ng. CEES J VOESENEK (WAGENINGEN UNIVERSITY, NETHERLANDS), To elucidate the underlying mechanisms, we developed an JOHAN L VAN LEEUWEN (WAGENINGEN UNIVERSITY, integrated 3D computational approach of hydrodynamics and NETHERLANDS) free-swimming body dynamics that couples the Navier-Stokes (NS) equations to the equations of undulating body motion. A [email protected] numerical approach is required to analyze the highly non-linear nature of the dynamics of large-amplitude undulatory swimming Zebrafish larvae are able to swim immediately after hatching, in the intermediate Reynolds regime. Using the model, we explored ma k i ng e ffec t ive escape ma noeuv res at t wo days post fe r t i l i zat ion how tail-beat frequency and amplitude of lateral curvature along (dpf). From 2 to 5 dpf, larval zebrafish improve swimming t he body a ffec t sw i m m i ng pe r for ma nce (i n te r m s of speed , flu id performance by increasing their tail-beat frequency and amplitude dynamic efficiency and cost of transport). The explored parameter ( Va n L eeuwen et a l. (2015) J. R . Soc. I nte r face 12: 20150 479). D u r i ng space extends beyond the experimentally observed frequency- t hese fi rst days of developme nt, t he la r vae’s mu sc le syste m c ha nges amplitude combinations in larval zebrafish. rapidly, while it continues functioning to power swimming. This Our computations predict that increasing both frequency and requires them to use their muscles differently across development. amplitude to swim faster improves swimming performance, which A fi rst step towards understanding how the lar vae achieve this agrees with previous experimental observations. This suggests and how they change their performance, is by computing the t hat fi sh la r vae adju st t hei r body k i ne mat ics to opt i m i ze sw i m m i ng time-dependent internal bending moment distributions along performance. In addition, a robust negative power relationship the body during swimming. This allows us to assess the changes bet wee n Re a nd St wa s pred ic ted , aga i n i n l i ne w it h e x pe r i me nta l ANNUAL MAIN MEETING BRIGHTON 2016 ANIMAL ABSTRACTS 45 observations, and irrespective of the employed combinations of frequency and curvature amplitude. The coupling between Re and A1.6 MOTOR SKILL DEVELOPMENT St i s not a n e ffec t of k i ne mat ic opt i m i zat ion , but resu lt s f rom flu id AND OPTIMAL MOVEMENT SPEEDS dynamic constraints. IN PREDATOR-PREY INTERACTIONS TUESDAY 5 JULY, 2016 16:40 A1.4 FIRST STEPS – THE EMERGENCE OF WALKING IN CHILDREN ROBBIE S WILSON (UNIVERSITY OF QUEENSLAND, AUSTRALIA) How fast should animals move when trying to escape predators or TUESDAY 5 JULY, 2016 14:45 capture prey? Most studies of animal performance assume faster is always better but this ignores the costs of high-speed movements NADIA DOMINICI (VU UNIVERSITY, NETHERLANDS) on the ability to successfully perform motor tasks. Because motor cont rol dec l i nes as a n i ma ls move faster, a n a n i ma l’s movement [email protected] speed shou ld re flec t a ba la nce bet ween t he bene fit s of mov i ng fa st against the costs of decreases in motor control and manoeuvrability. W hen neonates a re suppor ted for ~70 - 8 0 % of t hei r weig ht, t hey Usi ng a med iu m-si zed se m i-a rborea l ma rsupia l, t he Au st ra l ia n instinctively ‘walk’ as their feet come into contact with a horizontal northern quoll (Dasyurus hallucatus), I explore the costs of high su r face. T h i s ‘steppi ng re fle x ’ i s ha rdw i red i n ou r neu ra l c i rc u it r y. movement speeds on the accurate placement of their feet (motor In normally developing children, however, the ability to walk control) when moving on substrates differing in task difficulty independently emerges only about one year later. (varying beam widths). By developing a model of optimal movement Walking involves the coordinated activation of numerous speed s for prey whe n at te mpt i ng to escape predators, I t he n test muscles to provide forward progression while maintaining balance. whether the movement decisions of northern quolls reflect the I n t h i s ta l k I w i l l show t hat t he ce nt ra l ne r vou s syste m reduces t he u nde rly i ng t rade - off bet wee n speed a nd motor cont rol, t he cost s complexity of muscle coordination to a small number of elementary of mistakes, and the ability to improve motor control with practice commands. Like the phonetic units used in speech, these elementary and throughout development. locomotor commands, or locomotor primitives, can be combined in a flexible manner to generate a rich behavioural repertoire, including walking and running at different speeds, walking forwards or backwards, or walking with variable loads. I w i l l d i sc u ss how t he nu mbe r a nd t y pe of locomotor pr i m it ives c ha nge w it h developme nt i n a n i ma l s a nd hu ma n s.