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Prednáška 4Čo je život a ako ho študovať III.
Opportunity na Marse
Biologické systémy fungujú podľa pravidiel termodynamiky
ΔG = ΔH – TΔS
Zmena voľnej energie je vo vzťahu k zmene entalpie a entropie
Biologické systémy fungujú podľa pravidiel termodynamiky
Druhý zákon termodynamiky: v uzavretom systéme dochádza k zvyšovaniu neusporiadanosti a k znižovaniu voľnej (využiteľnej) energie
Voľná energia
Entropia
Sadava a kol. (2007). Life: The Science of Biology. Sinnauer Ass.
Ako je potom možné, že sú živé systémy usporiadané?
Biologické systémy fungujú podľa pravidiel termodynamikyV prípade endotermických procesov, pri ktorých je ΔG > 0 je potrebný prísun energie sú reakcie spriahnuté s exotermickými reakciami
Sadava a kol. (2007). Life: The Science of Biology. Sinnauer Ass.
Voľn
á en
ergi
a
Smer reakcie
Voľn
á en
ergi
aVoľn
á en
ergi
a
reaktanty
Tranzičný stav
Ea
ΔG
produkty
Chemické reakcie v živých organizmoch sú urýchľované katalyzátormi
Biologické systémy fungujú podľa pravidiel termodynamiky
ΔG0 = -RT ln[Y]/[X]
100% glukózo-1-P 95% glukózo-6-P 5% glukózo-1-P
Sadava a kol. (2007). Life: The Science of Biology. Sinnauer Ass.
Živé organizmy sú otvorené chemické systémy mimo rovnováhy
Sadava a kol. (2007). Life: The Science of Biology. Sinnauer Ass.
4. Život na Zemi je kontinuálny (abiogenéza vs. biogenéza)
Louis Pasteur(1822–1895)1859
Spoločné charakteristiky živých foriem na Zemi
ZÁVER: Živé organizmy vznikajú zo živých organizmov
rast mikroorgamizmov
VÝSLEDKY
žiadny rast
4. Život na Zemi je kontinuálnySpoločné charakteristiky živých foriem na Zemi
molekuly
bunky
tkanivá
orgány
organizmy
populácie
ekosystémy
biosféra
komunity
hypotéza Gaia(J. Lovelock)http://www.nature.com/nature/videoarchive/lovelock/
5. Život je hierarchizovanýSpoločné charakteristiky živých foriem na Zemi
6. Život je založený na dynamických interakciáchSpoločné charakteristiky živých foriem na Zemi
Sadava a kol. (2007). Life: The Science of Biology. Sinnauer Ass.
Dictyostelium discoideum –jednoduchý model bunkovej diferenciácie
agregácia „slimák“
„Stonka“„Stonka“
↓Živiny
https://www.youtube.com/watch?v=5h8WOWEqP6o
Produkcia „autoinduktora“
Indukcia odpovede susedov
Špecifická odpoveď bunkovej populácie
Koordinované správanie buniek u Dictyostelium discoideum
AGREGÁCIA
Negative feedback
Positive feedback
Feedforward relay
Inhibitory crosstalk
Stimulatory crosstalk
Komponenty živých systémov sú zostavené do sietí, v rámci ktorých medzi sebou interagujú
0
5
10
15
20
25
0 9 11 13 15 18 22 25
Čas (min)
cAM
P (p
mol
/mg
prot
eínu
/min
)
Vďaka týmto interakciám vykazujú živé systémy tzv. emergentné správanie, t.j. správanie, ktoré nie je možné dedukovať z vlastností individuálnych komponentov
Konc
entrá
cia
chem
ické
ho a
trakt
ora
D
C
B
A
c d
a b
g
f
e
Barabási, A.L. (2002). Linked. Perseus Publishing. (V pavučine sítí, 2005, Paseka)
Leonhard Euler a problém mostov v Královci
Robustnosť a SIEŤOVANIE
Biologické systémy sú reprezentované sieťami interakcií
6. Biologické adaptácie sú výsledkom evolúcie prostredníctvom prírodného výberu
Spoločné charakteristiky živých foriem na Zemi
Sadava a kol. (2007). Life: The Science of Biology. Sinnauer Ass.
Current Biology 24, 2156–2160, September 22, 2014 ª2014 Elsevier Ltd All rights reserved http://dx.doi.org/10.1016/j.cub.2014.07.059
ReportArcherfish Actively Controlthe Hydrodynamics of Their Jets
Peggy Gerullis1 and Stefan Schuster1,*1Department of Animal Physiology, University of Bayreuth,95440 Bayreuth, Germany
Summary
Among tool-using animals [1–4], none are known to adap-tively change the hydrodynamic properties of a free jet of wa-ter—a task considered difficult in human technology [5–7].Hunting archerfish can strike their targets with preciselyaimed water jets (e.g., [8, 9]), but they are also presentlythought to be unable to actively control the hydrodynamicsof their jets [8–13]. By using specifically trained fish, wewere able to monitor several aspects of jet production andpropagation as the fish fired at targets over a much widerrange of distances than previously explored [10, 13]. Weshow that jets that have to travel farther also live longer.Furthermore, the time needed until water assembles at thejet tip is not fixed. Rather, it is adjusted so that maximumfocusing occurs just before impact. Surprisingly, the fishachieve this by modulating the dynamics of changes in thecross-section of their mouth opening, a mechanism thatseems to not have been applied yet in human-built nozzles.The timing adjustments archerfish make in order to power-fully hit targets over an extended range strikingly parallelthe situation in the ‘‘uniquely human’’ ability of powerfulthrowing [14–18]. Based on the key role throwing played inhuman encephalization and cognitive evolution [14–20],skillfully ‘‘throwing’’ water should similarly have led to thecorrelated rapid evolution of cognitive skills in this animal.
Results and Discussion
In the field, archerfish can deliver powerful blows to targetsfrom more than 2 m distance (Movie S1 available online). Abrief powerful impact, needed to overcome prey attachment[10], could result if water that is released last catches up withthe tip [13]. Water has been found to be indeed ‘‘assembled’’at the tip [13] in jets aimed at very close targets (10 cm), result-ing in a force at impact that is comparable to forces measuredat 30 cm height [10]. Hence, a simple scenario could explainhow the fish hit prey with sufficient power throughout theirlarge hunting range: a speed gradient in the jet causes the wa-ter to be focused at the jet tip after about 10 cm. The focusedmass then travels upward, ready to hit any prey item in its path.We report here that this simple view is wrong and that instead,the fish adjust the distance at which water is maximallyfocused.
Specifically trained archerfish allowed us to monitor severalaspects of jet formation and propagation over a far wider rangeof preset target distances than previously examined. Thetrained fish fired accurate shots at targets presented at20 cm, 40 cm, and 60 cm height above the water’s surface,assuming defined position and orientation in each of theirshots and tolerating the strong illumination needed for
accurate high-speed recordings. In contrast to the scenariodescribed above, assembling of water at the tip is not gener-ally finished after 10 cm of travel. In jets fired at targets at60 cm height (Figures 1A and 1B), the jet tip was not completedeven after 30 cm of travel (Figure 1A) and was focused onlymuch later, before impact (Figure 1B). The difference in shapebetween the traveling ‘‘midway’’ and the ‘‘preimpact’’ jets is sorobust that it is easy to sort them out in a collection of images(Figure S1).Jets fired at close-range targets were fully focused much
earlier. A jet aimed at 20 cm height is focused at that height(Figure 1D), but a jet aimed at a target at 60 cm height is not(Figure 1A). However, jet tips recorded just before impactwere equally well focused, and their shapes bore no informa-tion on how long they had traveled before (Figures 1C and1D). To test this notion, we made use of the ease with whichhuman pattern vision can reliably detect differences in thecomplex structure of the jets (Figure S1). Twelve neutralobservers were asked to group a collection of 21 pictures ofpreimpact jet tips (seven for each target height) into three clas-ses. Despite considerable effort, the observers grouped theimages completely at random, with no relation to target height(p = 0.98, c2 test; see Experimental Procedures). Hence, imme-diately before impact, jets were equally well focused, regard-less of target height.En route views of the traveling jets revealed a further range-
dependent difference in the stability of the jets. Figure 1E illus-trates this with images of the shaft of the jets (see Figure S1)after a common path of 30 cm. The jets aimed at more distanttargets showed fewer modulations (Rayleigh instabilities,[21, 22]) in diameter, allowing human observers to groupthem in accordance with target height (p < 0.001, c2 test; n =30 images, 15 at each height, grouped by each of N = 8observers). Rare cases in which a jet had just missed theclose-range target (at 20 cm height) and disintegrated withoutinteracting with the target (see Experimental Procedures) wereparticularly instructive. When mixing en route views (obtainedafter 30 cm of travel) of the shaft of jets that were aimed at thethree different target distances, human observers could stillreadily predict target height even when they did not knowhow many examples belonged to each class (p < 0.001, c2
test; n = 7 images of jets, n = 17 images of jets, and n = 21 im-ages of jets after 30 cm travel distance but aimed at 20 cm,40 cm, and 60 cm height, respectively; N = 14 observers).Are the target-range adjustments reflected in the way the
jets are formed? Tip speed increased systematically in all ar-cherfish jets, tightly following (Figures 2A–2C; R2 > 0.99 in allcases) an empirical relation of the general form
vtipðtÞ=vmax 2Dv expð2 t=tÞ: (Equation 1)
Here, vmax denotes the hypothetical maximum speed the tipwould obtain (if water continued to flow out forever), Dv is thetotal increment in speed (from when the jet tip leaves themouth to vmax), and t is the time constant of the increase intip speed. In our analysis of 313 jets (Figure 2), the ranges ofthe three parameters were 5.8–6.8 ms21 (vmax), 2.7–3.8 ms21
(Dv), and 6.6–20.0 ms (t). Note that an increase in speed istypical for unsteady jets [21]. In contrast to a projectile firedfrom a gun, even a jet that rises against gravity can speed up*Correspondence: [email protected]
https://www.youtube.com/watch?v=S4G_MeUUZlI http://www.bbc.com/news/science-environment-29046018
as long as the tip is connected with water that flows out withincreasing speed. Most remarkably, the profile of increase inspeed depended on target height (nonlinear mixed effectsmodel: p < 0.001; Figures 2A–2C; Table S1 and Figure S2; totalwater volume is independent of height [10]). Both fish system-atically raised the speed increment Dv with target height (p <0.001; Figure 2D) and thus adjusted the difference in speed be-tweenwater released first andwater released last according totarget height.
The general pattern of increase in speed at the tip (Equation1) does not also determine the stability of the jets. Figures 2Eand 2F show jets mimicked with syringes that either stayedcoherent while water left the syringe or broke up before all wa-ter had left the syringe. Despite their very different stability,they did not significantly differ in the time course of speed in-crease at their tips (Figures 2E and 2F; difference in vmax, Dv,and t: p > 0.05 in each case). The truemastery of the fish there-fore seems to be covarying the stability and the initial speedprofile of their jets. To shoot, archerfish rapidly compress theirgill covers, forcing water out from a ‘‘gun barrel’’ whose upperhalf is a ridge in the roof of their mouth and whose bottom half
is formed by the hardened surface of their tongue [10–12] (Fig-ure S3). Water does not leave this gun barrel directly into theair, but it leaves after passage of an enlargement. A similararrangement reduces the production of satellite drops in themammalian penis [23] and may have a similar stabilizing func-tion for archerfish jets.Given the apparent rigidity of the shooting apparatus, we
first looked for chemical ways by which the fish could controlthe hydrodynamics of their jets. Dynamic viscosity h and sur-face tension s affect the so-called Ohnesorge number
Oh=h=ðLrsÞ1=2; (Equation 2)
which determines the stability of a free jet [5] formed with acharacteristic length L from a fluid with density r. It is well es-tablished that even the presence of small traces of chemicalscan strongly affect this number [24] so that the fish could chem-ically adjust their jets by adding more or less substances to it.We therefore analyzed the surface tension and the shearing-rate dependence of viscosity directly in the water that the fishhad fired. However, surface tension in these samples was
20 40 60
D
E
1 cm
1 cm
P < 0.001
P = 0.98
A C
20
40
60
0
Hei
ght (
cm)
Target height (cm)midway
1cm
B
pre-impact
Figure 1. Focus Distance and Instability ofArcherfish Jets Are Not Fixed but Depend onTarget Distance
Trained archerfish allowed us to monitor severalaspects of their jet production, from formation un-til impact, as they engaged targets (black dots) at20 cm, 40 cm, or 60 cm height above water level.(A and B) Examples of jets fired at a target at60 cm height. Although water has assembled atthe tip before impact (B), this has not yet fullyoccurred after 30 cm of travel (A) (see also Fig-ure S1).(C) Areasmarked blue and red schematically indi-cate preimpact and en route phases of jets,respectively, shown in (D) and (E).(D) Examples (from 39 recordings) of preimpactjet tips (1 cm before impact) showing that water
can be focused much earlier, depending on target height. Preimpact focusing is equally well at all height levels, and images of preimpact tip contain noinformation on how far the jet had traveled before (p = 0.98; c2 test).(E) In addition to when the tip forms, stability of main shaft of jet differs, depending on target height. Examples of jets (from 83 recordings) observed after acommon distance of 30 cm (schematically depicted at 30 cm height) contain information on target distance (p < 0.001; c2 test).
Spee
dat
tip
(m/s
)Sp
eed
incr
emen
t∆v
(m/s
)
Target height (cm)
220
3
4
40 60
Spee
d at
tip
(m/s
)
0
2
4
Time (ms)0 16
Time (ms)0 16 32 32
D E FTime (ms)
0
2
4
1 cm 1 cm
stable broken up
10 200
6
4
2
A B C
10 20010 200
6
4
2
6
4
2
Time (ms)Time (ms)
20 cm
60 cm40 cm
Figure 2. Archerfish Adjust the SpeedGradient ofTheir Jets According to Target Height
(A–C) Depiction of how speed at jet tip followedthe general relation vtip(t) = vmax 2 Dv exp(2t/t)(vmax, maximum speed; Dv, speed increment; t,time constant) at each target height (20 cm,40 cm, and 60 cm). Time course of tip speed dur-ing first 20 ms for shots fired by fish 2 is shown(see Figure S2 for fish 1). Points are averages of41, 57, and 44 speed measurements (all fits inA–C, R2 > 0.99).(D) Speed increment Dv significantly increasedwhen jets were launched toward higher targets(mean 6 5% confidence intervals for fish 1[filled-in bar] and fish 2 [open bar]; all differencesp < 0.001).(E and F) The time course of tip speed does notgenerally predict stability. Mimicking the archer-fish’s pattern of increase in tip speed can leadto stable (E) or unstable (F) jets (see examples ininsets).
Archerfish Shape Their Jets2157
Current Biology 24, 2156–2160, September 22, 2014 ª2014 Elsevier Ltd All rights reserved http://dx.doi.org/10.1016/j.cub.2014.07.059
ReportArcherfish Actively Controlthe Hydrodynamics of Their Jets
Peggy Gerullis1 and Stefan Schuster1,*1Department of Animal Physiology, University of Bayreuth,95440 Bayreuth, Germany
Summary
Among tool-using animals [1–4], none are known to adap-tively change the hydrodynamic properties of a free jet of wa-ter—a task considered difficult in human technology [5–7].Hunting archerfish can strike their targets with preciselyaimed water jets (e.g., [8, 9]), but they are also presentlythought to be unable to actively control the hydrodynamicsof their jets [8–13]. By using specifically trained fish, wewere able to monitor several aspects of jet production andpropagation as the fish fired at targets over a much widerrange of distances than previously explored [10, 13]. Weshow that jets that have to travel farther also live longer.Furthermore, the time needed until water assembles at thejet tip is not fixed. Rather, it is adjusted so that maximumfocusing occurs just before impact. Surprisingly, the fishachieve this by modulating the dynamics of changes in thecross-section of their mouth opening, a mechanism thatseems to not have been applied yet in human-built nozzles.The timing adjustments archerfish make in order to power-fully hit targets over an extended range strikingly parallelthe situation in the ‘‘uniquely human’’ ability of powerfulthrowing [14–18]. Based on the key role throwing played inhuman encephalization and cognitive evolution [14–20],skillfully ‘‘throwing’’ water should similarly have led to thecorrelated rapid evolution of cognitive skills in this animal.
Results and Discussion
In the field, archerfish can deliver powerful blows to targetsfrom more than 2 m distance (Movie S1 available online). Abrief powerful impact, needed to overcome prey attachment[10], could result if water that is released last catches up withthe tip [13]. Water has been found to be indeed ‘‘assembled’’at the tip [13] in jets aimed at very close targets (10 cm), result-ing in a force at impact that is comparable to forces measuredat 30 cm height [10]. Hence, a simple scenario could explainhow the fish hit prey with sufficient power throughout theirlarge hunting range: a speed gradient in the jet causes the wa-ter to be focused at the jet tip after about 10 cm. The focusedmass then travels upward, ready to hit any prey item in its path.We report here that this simple view is wrong and that instead,the fish adjust the distance at which water is maximallyfocused.
Specifically trained archerfish allowed us to monitor severalaspects of jet formation and propagation over a far wider rangeof preset target distances than previously examined. Thetrained fish fired accurate shots at targets presented at20 cm, 40 cm, and 60 cm height above the water’s surface,assuming defined position and orientation in each of theirshots and tolerating the strong illumination needed for
accurate high-speed recordings. In contrast to the scenariodescribed above, assembling of water at the tip is not gener-ally finished after 10 cm of travel. In jets fired at targets at60 cm height (Figures 1A and 1B), the jet tip was not completedeven after 30 cm of travel (Figure 1A) and was focused onlymuch later, before impact (Figure 1B). The difference in shapebetween the traveling ‘‘midway’’ and the ‘‘preimpact’’ jets is sorobust that it is easy to sort them out in a collection of images(Figure S1).Jets fired at close-range targets were fully focused much
earlier. A jet aimed at 20 cm height is focused at that height(Figure 1D), but a jet aimed at a target at 60 cm height is not(Figure 1A). However, jet tips recorded just before impactwere equally well focused, and their shapes bore no informa-tion on how long they had traveled before (Figures 1C and1D). To test this notion, we made use of the ease with whichhuman pattern vision can reliably detect differences in thecomplex structure of the jets (Figure S1). Twelve neutralobservers were asked to group a collection of 21 pictures ofpreimpact jet tips (seven for each target height) into three clas-ses. Despite considerable effort, the observers grouped theimages completely at random, with no relation to target height(p = 0.98, c2 test; see Experimental Procedures). Hence, imme-diately before impact, jets were equally well focused, regard-less of target height.En route views of the traveling jets revealed a further range-
dependent difference in the stability of the jets. Figure 1E illus-trates this with images of the shaft of the jets (see Figure S1)after a common path of 30 cm. The jets aimed at more distanttargets showed fewer modulations (Rayleigh instabilities,[21, 22]) in diameter, allowing human observers to groupthem in accordance with target height (p < 0.001, c2 test; n =30 images, 15 at each height, grouped by each of N = 8observers). Rare cases in which a jet had just missed theclose-range target (at 20 cm height) and disintegrated withoutinteracting with the target (see Experimental Procedures) wereparticularly instructive. When mixing en route views (obtainedafter 30 cm of travel) of the shaft of jets that were aimed at thethree different target distances, human observers could stillreadily predict target height even when they did not knowhow many examples belonged to each class (p < 0.001, c2
test; n = 7 images of jets, n = 17 images of jets, and n = 21 im-ages of jets after 30 cm travel distance but aimed at 20 cm,40 cm, and 60 cm height, respectively; N = 14 observers).Are the target-range adjustments reflected in the way the
jets are formed? Tip speed increased systematically in all ar-cherfish jets, tightly following (Figures 2A–2C; R2 > 0.99 in allcases) an empirical relation of the general form
vtipðtÞ=vmax 2Dv expð2 t=tÞ: (Equation 1)
Here, vmax denotes the hypothetical maximum speed the tipwould obtain (if water continued to flow out forever), Dv is thetotal increment in speed (from when the jet tip leaves themouth to vmax), and t is the time constant of the increase intip speed. In our analysis of 313 jets (Figure 2), the ranges ofthe three parameters were 5.8–6.8 ms21 (vmax), 2.7–3.8 ms21
(Dv), and 6.6–20.0 ms (t). Note that an increase in speed istypical for unsteady jets [21]. In contrast to a projectile firedfrom a gun, even a jet that rises against gravity can speed up*Correspondence: [email protected]
Charakteristiky životaObchádzanie dizorganizácieUsporiadanosť Každá štruktúra/aktivita je v špecifickom vzťahu s inou
štruktúrou/aktivitouAdaptácia Špecifické štruktúry a správanie umožňuje organizmu
prežívať v danom prostredíMetabolizmus Siete chemických reakcií umožňujúcich premenu energie,
a jej využitie na dôležité životné funkcieAktívny pohyb Využitie vlastných síl organizmu na pohyb v danom
prostredíDráždivosť Schopnosť organizmu detegovať signály v prostredí a
reagovať na ne
Reprodukcia Schopnosť organizmu produkovať nové jedince toho istého typu
Ontogenéza, vývin Usporiadaná séria progresívnych zmien vedúcich k zvýšenému stupňu komplexnosti (zložitosti)
Gény Organizmy majú k dispozícii jednotky dedičnosti, ktoré kontrolujú ich vlastnosti
Evolúcia Počas evolúcie získavajú organizmy nové spôsoby prežívania a reprodukcie v danom prostredí
Pokračovanie skupiny napriek smrti jednotlivcov
Ako je možné experimentálne študovať komplikované biologické fenomény?
Redukcia komplikovaného problému na jednoduché otázky je predpokladom pre pochopenie zložitých fenoménov
REDUKCIONIZMUS VS HOLIZMUS
Najefektívnejší spôsob štúdia biologického fenoménu je študovať ho v najjednoduchšom biologickom systéme, u ktorého bol identifikovaný
DELBRÜCKOV PRINCÍP
Jednoduché organizmy ako model pre štúdium zložitých biologických fenoménov
KVASINKY (Saccharomyces cerevisiae):Základy bioenergetikyPrincípy biogenézy bunkových organelPrincípy regulácie bunkového cykluPaul Nurse, Leland Hartwell, Nobelova cena (2001)
HMYZ (Drosophila melanogaster):Chromozómový základ dedičnostiPrincípy ontogenézy (vývinu)Princípy behaviorálnej genetikyThomas Morgan, Nobelova cena (1933)Christiane Nüsslein-Volhard, Nobelova cena (1995)
BAKTERIOFÁGY:Základy molekulárnej genetikyMax Delbrück, Nobelova cena (1969)
Princípy vezikulárneho transportu v bunkáchRandy Schekman, Nobelova cena (2013)
Jednoduché organizmy ako model pre štúdium zložitých biologických fenoménov
ČERVY (Caeonorhabditis elegans):Princípy vývinovej biológieZáklady programovanej bunkovej smrtiGenetický základ starnutiaSydney Brenner, Robert Horwitz, John Sulston, Nobelova cena (2002)
MÄKKÝŠE (Aplysia):Základy neurobiológieEric Kandel, Nobelova cena (2000)
OBOJŽIVELNÍKY (Xenopus laevis):Základy vývinovej biológieHans Speman, Nobelova cena (1935)Tim Hunt, Nobelova cena (2001)
http://www.dailymotion.com/video/xjhxzw_memory-research-aplysia-californica-memorable-snail_school
Jednoduché organizmy ako model pre štúdium zložitých biologických fenoménov
Arabidopsis thaliana
• Krátky životný cyklus (6 týždňov)
• Relatívne malý genóm (125 miliónov párov báz)
• Možnosť ľahkej genetickej manipulácie
• ...
Jednoduché organizmy ako model pre štúdium zložitých biologických fenoménov
Danio rerio
Jednoduché organizmy ako model pre štúdium zložitých biologických fenoménov
Mus musculus
Heterocephalus glaber, Naked mole-rat, krtkopotkan holý
Extrémna dĺžka života: 30 rokov (myš 4 roky)Rezistencia k onkologickým transformáciámBunky H. glaber vykazujú fenomén skorej kontaktnej inhibície in vitro(ECI, early contact inhibition)
Štúdium modelových organizmov môže byť dôležité pre klinickú medicínu
Bunky H. glaber sekretujú vysokomulekulárny hyaluronan
Tian et al. (2013). Nature 499: 346-349.
HA, hylarunonan
HAase, hyaluronidaseHAS, HA synthaseNMR, naked mole rat; GP, guinea pig; M, mouse; H, human; SF, skin fibroblasts
Čo určuje naše správanie? Základné princípy genetiky správania boli odvodené zo štúdia modelových organizmov
Dvorenie samčeka u Drosophila melanogaster
Fruitless (FRU): Kontrolór pohlavnej identity nervového systému Drosophila melanogaster
fruitless samčekovia sú bisexuálni, v spoločnosti samčekov tvoria „retiazky“ (courtship chains)
Dvorenie drozofíl je pod genetickou kontrolou
Demir, E., Dickson, B.J. (2005) Cell 121, 785-794
Agresívne správanie drozofíl ako model pre genetiku správania človeka
Chen, S. a kol. (2002) Proc. Natl. Acad. Sci. USA 99, 5664-5668
Výstraha krídlami Šermovanie
Boxovanie Obranné gesto porazeného
Experimentálna komôrka
Nilsen, S. P. a kol. (2004). Proc. Natl. Acad. Sci. USA 101, 12342-12347Yurkovic, A. a kol. (2006). Proc. Natl. Acad. Sci. USA 103, 17519-17524
Vzorce agresívneho správania sa odlišujú medzi samcami a samičkami D. melanogaster
Bojové techniky špecifické pre samcov: Boxovanie, „Tussling“ Bojové techniky špecifické pre samičky: „Head-butting“