design to study movements and

(1)

‘Cosmodrome’: an experimental

design to study movements and

behavior of the banana weevil,

Cosmopolites sordidus, using RFID

Dominique Carval

(2)

(3)

Cosmopolites sordidus

(Cuillé 1950; Roth & Willis 1963; Gold et al. 2001)

(4)

Walking insect

(5)

Walking insect

Major pest of banana crops Nocturnally active

(6)

Walking insect

(7)

Walking insect

Hygrotropic Cryptic

(8)

Walking insect

Hygrotropic Cryptic

(9)

(Gold et al. 2001)

(10)

females are larger than males (p-value < 0.0001) 0 2 4 6 8 10 12 14 16 18 20 P er cen t of ba nn ana w ee vil Size (mm) Females Males Cosmopolites sordidus Sexual dimorphism (Gold et al. 2001)

(11)

Sexual dimorphism

(12)

Sexual dimorphism

Last abdominal sternite ♀

Last abdominal sternite ♂

(13)

Sexual dimorphism

Last abdominal sternite ♀

Rostrum ♂ Rostrum ♀

Last abdominal sternite ♂

(14)

Walking insecte

Dispersion & movements Hygrotropic

Cryptic

(15)

(16)

Dispersion & movements

Slow and limited(1)

e.g. 0.5 meter per day

e.g. maximal distance of 9 meters per day

(17)

Habitat dependant(2)

Slow and limited(1)

e.g. bare soil → probability of departure is high e.g. banana plant → probability to stay is high

(18)

Habitat dependant(2)

Slow and limited(1)

e.g. bare soil → probability of departure is high e.g. banana plant → probability to stay is high

Humidity(3)

e.g. high humidity → sedentarity e.g. low humidity → unsettlement

(19)

((1)Vinatier et al. 2009; (2)Vinatier et al. 2011; (3)Roth & Willis 1963)

Epidemiological front = colonization of banana plots

Spatial organization, habitat dependence Interaction between individuals

Study of the behavioral response at local scale Movements between neighbors banana plants Local sex ratio

Local density of individuals by banana plant Local mating

(20)

Walking insect

Dispersion & movements Hygrotropic

Cryptic

Sexual dimorphism

(21)

Density effects

(22)

Density effects

Oviposition rate is higher at low density

(23)

Density effects

Larval survivorship is higher at low density

(24)

Density effects

Larval survivorship is higher at low density

Larval developpment is quicker at high density

(25)

Does the local density of banana weevil affect the behavior of individuals ?

(26)

(27)

Experimental design

Patch A Patch B

(28)

← 1 meter →

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← 1 meter →

Patch A Patch B

(30)

← 1 meter →

Patch A Patch B

antennas + recorders marked individuals

(31)

Patch A Patch B

detection and recording !!!

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(33)

!!! detection and recording

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Patch A Patch B

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(36)

(37)

(38)

Patch A : rhizome Patch B : rhizome

variation in density of marked individuals

(39)

(40)

(41)

(42)

Results

(43)

Results

Proportion of movers

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Results

Proportion of movers

Mean number of moves

Generalized linear mixed models (GLMMs)

(45)

Results

(Bolker et al. 2009)

glmer function

lme4 - R.2.13.0

(46)

Results

Sex

glmer function

lme4 - R.2.13.0

(47)

Results

Sex Density (d)

glmer function

lme4 - R.2.13.0

(48)

Results (Bolker et al. 2009) Sex Density (d) Error Proportion of movers

glmer function

lme4 - R.2.13.0

Poisson Binomial

(49)

Results (Bolker et al. 2009) Sex Density (d) Error Random effects Proportion of movers

glmer function

lme4 - R.2.13.0

Experiment Individual

Poisson Binomial

(50)

Results

(51)

0 10 20 30 40 50 60 0 1 2 3 4 5 6 7 8 9 10 11 P e rce n tag e of in d ivid u als Number of movements females males Results Proportion of movers

(52)

Results Proportion of movers 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 10 20 30 40 P e rce n tag e of mov e rs Number of individuals

predict females predict males

(53)

Results

Proportion of movers

Model df AIC Δ AIC Log-Likelihood P-value

sex + d + d² + 1/d sex * d + d² + 1/d sex * d + d² sex * d + 1/d sex * d sex Null 7 8 6 6 5 4 3 388.8 387.6 400.5 413.3 411.6 410.1 411.0 1.2 11.7 24.5 22.8 21.3 21.2 -187.38 -185.83 -194.25 -199.80 -201.05 -202.52 0.08 < 0.001 < 0.0001 < 0.0001 < 0.0001 < 0.0001 -200.66

(54)

Results

sex + d + d² + 1/d sex * d + d² + 1/d sex * d + d² sex * d + 1/d sex * d sex Null 7 8 6 6 5 4 3 388.8 387.6 400.5 413.3 411.6 410.1 411.0 1.2 11.7 24.5 22.8 21.3 21.2 -187.38 -185.83 -194.25 -199.80 -201.05 -202.52 0.08 < 0.001 < 0.0001 < 0.0001 < 0.0001 < 0.0001 -200.66

(55)

Results

prediction of the model : sex and density effects

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 10 20 30 40 P e rce n tag e of mov e rs Number of individuals

(56)

Results

prediction of the model : sex and density effects

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 10 20 30 40 P e rce n tag e of mov e rs Number of individuals

predict females predict males data females data males

(57)

Results

(58)

Results

More individuals move at very low and intermediate densities

(59)

Results

More individuals move at very low and intermediate densities Percentage of individuals that moves is

(60)

Results

Individual mean number of movements

0 1 2 3 4 5 6 0 10 20 30 40 Me an n u mb e r o f mo ve me nts Number of individuals

(61)

Results

sex * d + d² + 1/d sex * d + d² sex * d + 1/d sex * d sex Null 8 7 7 6 4 3 520.6 550.5 568.7 566.9 566.8 568.5 29.9 48.1 46.3 46.2 47.9.6 -252.28 -268.23 -277.35 -277.47 -279.42 -281.23 < 0.0001 < 0.0001 < 0.0001 < 0.0001 < 0.0001 sex + d + d² + 1/d 7 524.7 4.1 -268.23 < 0.05

(62)

Results

sex * d + d² + 1/d sex * d + d² sex * d + 1/d sex * d sex Null 8 7 7 6 4 3 520.6 550.5 568.7 566.9 566.8 568.5 29.9 48.1 46.3 46.2 47.9.6 -252.28 -268.23 -277.35 -277.47 -279.42 -281.23 < 0.0001 < 0.0001 < 0.0001 < 0.0001 < 0.0001 sex + d + d² + 1/d 7 524.7 4.1 -268.23 < 0.05

(63)

Results

Individual mean number of movements prediction of the model : sex and density effects

(64)

Results

Individual mean number of movements prediction of the model : sex and density effects

predict females predict males data females data males

(65)

Results

Individuals move more at very low and intermediate densities

(66)

Results

Individuals move more at very low and intermediate densities

(67)

(68)

Discussion & Perspectives

How to explain the behavior of C. sordidus in response to variation in local density of patch?

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(70)

Mating

(71)

Mating Resources

(72)

Local density of individuals

Mates Resources

(73)

available mates

(74)

available mates

-available resources ++

(75)

available mates +

(76)

available mates +

(77)

available mates ++

(78)

--Discussion & Perspectives

available resources

(79)

(80)

---Discussion & Perspectives

available resources

(81)

Hypothesis : two effects of the local density

How to explain the difference in response to variation in local density of patch between males and females?

(82)

Hypothesis : two effects of the local density

How to explain the difference in response to variation in local density of patch between males and females?

(83)

(84)

More replicates are needed ! Effect of the sex ratio

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(86)

Effect of the size of individuals Effect of the mating status

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(88)

Modelisation of the patch choice