Aggressive Behavior and Aggressive Behavior and Dominance in Dominance in Gerris latiabdominisGerris latiabdominis

2006-10900 Kwak Se Hyun2006-10923 Pak Sun Mi

1. Introduction

1) PURPOSE : Relationship with

Aggressive behavior and Size 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) Methods :

a) Collecting G. latiabdominisb) 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 individualsd) Starving them for 3 days in order to increase the

frequency of their aggressive behaviore) Observing Interactions between 2 individuals

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

Size Distribution of Male

0

2

4

6

8

10

N =36

NUMBER

Bell-shaped distribution

Few G.latiabdominis have very small

size

Most G.latiabdominis

have middle size

Few G.latiabdominishave very large

size

Size Distribution of Female(1)

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1012141618

0.99 1.02 1.05 1.08 1.11 1.14 1.17

1) 1st

N=51

NUMBER

: Small size group

: Large size group

Size Distribution of Female(2)

0

2

4

6

8

10

12

0.98 1 1.02 1.04 1.06 1.08 1.1

N=48

1) 2nd

NUMBER

: Small size group

: Large size group

2. Results and Discussion 2.1. Pattern of Behavior

0

20

40

60

80

100

SS SL LL

Nothing

Signaling

FightingHigh Up

N=90 N=90 N=90

(%)

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

AGGRESSIVE BEHAVIORS in G. latiabdominis

2.2. Effect of Size

No signal+ Fight + High-up

0.00%10.00%20.00%30.00%40.00%50.00%60.00%70.00%80.00%90.00%

100.00%

SL

S WINNER

L WINNER

N=1

N=10

Gerris latiabdominis’ dominance was highly and positively correlated with body size

SIZE&DOMINANCE

2.3. Effect of Aggressive Behaviors (1) Fighting

0

2

4

6

8

10

12

14

SS

SL

LL

(%)

N=2 N=4

N=10

There is considerably more fighting behavior in the LL group

2.3. Effect of Behaviors (2) Signaling

(a) ROLE OF SIGNALING

27 25

2 4

05

1015202530

SS LL

NU

MB

ER

SP SA

SA SP

N=29 N=29

*SP SA= SP:winner/SA:looser

SA SP= SA:winner/SP:looser

*SP=Signaling Present

SA=Signaling Absent

SPSA make up over 93.1% / 86.2%

(b) Deeper Look about Signaling

0

20

40

60

80

100

SS SL0

20

40

60

80

100

LL SL

The rate of success in Signaling

(%) (%)

N=50 N=19

N=40 N=29

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

(b) Deeper Look about Signaling

0102030405060708090

SS SL

++

+/-

0102030405060708090

LL SL

++

+/-

The rate of success in Signaling

N=40 N=29N=50 N=19(%) (%)

•++ : Both G.lacustris signal when they interact each other

•+/- : Only one G.lacustris signal when they interact each other

Proportion of ++

is higher in SL

(a) ROLE OF High-Up

10 10

34

02468

1012

SS LL

NU

MB

ER

HP HA

HA HP

N=13 N=14

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%

0

20

40

60

80

100

SS SL

0

20

40

60

80

100

LL SL

The rate of success in HIGH -UP

(b) Deeper Look about High-Up

N=18

N=9 N=22 N=13

The presence of large one appears to reduce the rate of success in high-up of small G.latiabdominis

(b) Deeper Look about High-Up

0

20

40

60

80

100

SS SL

++

+/-

0

20

40

60

80

100

LL SL

++

+/-

The rate of success in HIGH -UP

N=18 N=9 N=22 N=13(%)

(%)

Proportion of ++

is higher in SL

•++ : Both G.lacustris signal when they interact each other

•+/- : Only one G.lacustris signal when they interact each other

2.3. Effect of Behaviors (3)SIGNALING AND HIGH-UP

02468

1012

HSP A

NU

MB

ER

SS+LL

N = 10

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

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