Aggressive Behavior and Dominance in Gerris latiabdominis

1. Aggressive Behavior and Dominance in Gerris latiabdominis 2006-10900 Kwak Se Hyun 2006-10923 Pak Sun Mi

2. 1. Introduction • PURPOSE : Relationship with Aggressive behavior andSize dominance of G.latiabdominis What’s the dominance? We define “Dominance” as the one who doesn’t step off earlier 2) Materials : Waterstrider- Gerris latiabdominis • Small species among waterstriders • Abundant in rice field and serene riffles in the mountain

3. 3) Methods : • Collecting G. latiabdominis • Distinguish of Sex : use ONLY FEMALE In order to exclude mating behavior during aggressive interactions c)Measuring body size & Separating them into 3 groups : Small / Middle/ Large use ONLY SMALL & LARGE sized individuals • Starving them for 3 days in order to increase the frequency of their aggressive behavior • Observing Interactions between 2 individuals

4. 4)Way to distinguish of sex (a) size : Female is usually larger than male (b) different shape of genitalia Male: Diamond shape/ Female: Triangular shape

5. Size Distribution of Male NUMBER Most G.latiabdominis have middle size N =36 Few G.latiabdominis have very small size Few G.latiabdominis have very large size Bell-shaped distribution

6. Size Distribution of Female(1) 1) 1st NUMBER N=51

7. : Small size group : Large size group

8. Size Distribution of Female(2) • 2nd NUMBER N=48

9. : Small size group : Large size group

10. 2. Results and Discussion2.1. Pattern of Behavior (%) N=90 N=90 N=90

11. AGGRESSIVE BEHAVIORS in G. latiabdominis SIGNALING Wave signals produced by Bouncing the body Larger (or Heavier) the body, Stronger the signals Many waterstrider species use wave signals for sending information FIGHTING The strongest interaction Pushing with legs HIGH-UP Raising the body with raising mid & hind legs

12. 2.2. Effect of SizeNo signal+ Fight + High-up SIZE & DOMINANCE N=10 N=1 Gerris latiabdominis’ dominance was highly and positively correlated with body size

13. 2.3. Effect of Aggressive Behaviors(1) Fighting (%) N=10 N=4 N=2 There is considerably more fighting behavior in the LL group

14. 2.3. Effect of Behaviors (2) Signaling *SP=Signaling Present SA=Signaling Absent *SP SA= SP:winner/SA:looser SA SP= SA:winner/SP:looser SPSA make up over 93.1% / 86.2%

15. (b) Deeper Look about Signaling The presence of large one appears to reduce the rate of success in signaling of small G.latiabdominis Large G.latiabdominis interacting with small one shows slightly higher rate of success in signaling compared to large one interacting with large (%) (%) N=40 N=29 N=50 N=19 The rate of success in Signaling

16. (b) Deeper Look about Signaling Proportion of ++ is higher in SL (%) (%) N=50 N=19 N=40 N=29 The rate of success in Signaling • ++ : Both G.lacustris signalwhen they interact each other • +/- : Only one G.lacustris signal when they interact each other

17. 2.3. Effect of Behaviors(2) High-Up *HP=High-Up Present HA=High-Up Absent *HP HA= HP:winner/HA:looser HA HP= HA:winner/HP:looser HPHA make up over 76.9% / 71.4%

18. (b) Deeper Look about High-Up The presence of large one appears to reduce the rate of success in high-up of small G.latiabdominis N=18 N=13 N=22 N=9 The rate of success in HIGH -UP

19. (b) Deeper Look about High-Up Proportion of ++ is higher in SL (%) (%) N=22 N=13 N=18 N=9 The rate of success in HIGH -UP • ++ : Both G.lacustris signalwhen they interact each other • +/- : Only one G.lacustris signal when they interact each other

20. Both high-up and signaling shows strong effect on dominance of G.latiabdominis

21. 3. Conclusion • G.latiabdominis’ aggressive behaviors are composed of fighting, signaling, and high-up. • Positive relationship > New DISCOVERY! • Body size and dominance • Signaling and dominance • High-up and dominance