Aspects of the ecology of fruit flies in uganda

Diversity, Host Utilization and Ecological Niche of Fruit Flies (Diptera: Tephritidae) in Uganda

ISABIRYE BRIAN ERIPHAZ, [email protected]

2

Acknowledgements

3

Background… Agriculture…Global and Uganda

Employs 45% of the working global population and over 80% in most parts of Africa and Asia!

Uganda•Export:

90%

•Employment:80%

•People living in rural areas : 85%

•Source of raw materials…….

4

Lucrative Horticulture Industry…..

http://houseofdawda.com/fresh_juices.html

5

Trade: Dynamic and highly vibrant!

Center on Globalization, Governance & Competitiveness, Duke University, 2011

6

Key Players in the fruit trade

• Global import of fruits hit US$4.3 million tons in the year 2010. In which 87% or 3.8 million tons were imported by developed countries.

• The US and the EU market represents 70% of global import of tropical fruits.

• The EU is the largest tropical fruit importer with the major consumer of France and the main transshipment port of the Netherlands.

• The US and Japan, Canada and Hong Kong are also large importers (USDA, 2007).

7

Fruit industry in Uganda….the positive side!

8

Bad news for most fruit producers!

Y2003 Y2004 Y2005 Y2006 Y2007 Y2008 Y2009 Y20100

1000

2000

3000

4000

5000

6000

7000

8000

9000

0

1000000

2000000

3000000

4000000

5000000

6000000

Volume (Tonnes) Value (US$)

Period (Years)

Volu

me

(Ton

nes)

(Source: UNEPB)

Valu

e (U

S$)

9

Common Challenge: Tephritid FF

Life Cycle

10

Negatively affect fruit trade

11

Problem/ Motivation…• Fruit flies cause about 40% fruit loss in Africa, and about 73% in Uganda

• Design of IPM strategies for fruit flies requires knowledge of their biology.

• Was limited to Nakasinga, 2002; Nemeye, 2005; Okullokwany, 2006.

• It is not clear how:

• Diversity has been shaped by hosts, distribution and envital variability.

• Highly cryptic and inter-intra-specific morphological variation (Clarke

et al., 2005; Drew et al., 2008) among Bactrocera spp. turns out.

• Will change in climate alter the suitability and distribution of species?

12

Objectives and HypothesisesMain ObjectiveTo describe the diversity, host utilization and ecological niche of major tephritid fruit flies in Uganda.

Specific Objective1. Determine the species diversity of fruit flies across selected agro ecological zones 2. Assess fruit fly host utilization in the different agro ecological zones. 3. Characterise the morphometric variability of the most important fruit fly species

among hosts and mango growing zones4. Determine the current and potential future spatial distribution of the major Tephritid

fruit fly species in Uganda.

Hypotheses1. There is no significant difference in the diversity of fruit flies in the different ecological

zones in Uganda.2. There is no significant difference in fruit fly host utilisation patterns in the different

ecological zones and among host types in Uganda.3. There is no significant morphometric heterogeneity among B. invadens populations

infesting different hosts in the different ecological zones in Uganda.4. Fruit fly species’ current and future distribution and ecological niches is random across

the different ecological zones in Uganda

13

Study IV: Morphometric (intra species) Diversity

Diversity, Host Utilisation and Ecological Niche of Tephritid (Diptera: Tephritidae) Fruit flies in Uganda

Ecological Nichie and Distribution Studies

Fruit Fly Diversity Studies

Study I: Species Diversity

Study III: Effect of Host Type and Variety on Fitness/ Survival Study II: Fruit fly Host Utilisation in Uganda

Study VI: Projected Effect of Climate Change on Distribution

Study V: Actual and potential Distribution of Fruit Flies in Uganda

Host Utilisation Studies

Results scheme and flow…

14

STUDY ONE: INTER SPECIES DIVERSITY

“When you have seen one ant, one bird, one tree, you have not seen them all” E. O. Wilson

15

Introduction• FF are key pests of several fruit crops (Ekesi et al., 2006; Mayamba et al.,

2015)

• Yield losses can exceed 80% (Ekesi et al., 2006; Mayamba et al., 2014)

• Correct identification is key in sustainable management (Jang et al., 2003)

• Regional efforts (Mwatawala et al., 2006; 2009; Rwomushana et al., 2008; Geurts et al., 2012), but in Uganda (Nakasinga, 2002, Okullokwany, 2006)

• This study set out to: 1. Identify the fruit fly species present in the country, and2. Assess the fruit fly community structure across three mango

production AEZs


16

Mat. and MethodsWestern Medium High Altitude Farmlands (WMHF), Lake Victoria Crescent (LVC) and Northern Moist Farmlands (NMF) (Wortman and Eledu, 1993)


%[

%[%[

%[

%[%[

%[%[

%[

%[

%[

%[

%[

%[

%[

%[%[

%[

LIRA

APAC

GULU

OYAM

KASESE

AMURU

RAKAI

SOROTI

WAKISO

MUKONO

PADER

MITYANAKABAROLE

MPIGI

MASAKA

IGANGA

AGAGO

MAYUGE

IBANDA

BUSIA

RUKUNGIRI

DOKOLO

RUBIRIZI

KIBINGO

TORORO

AMOLOTAR

LAMWO

KAMULI

KIRYANDONGO

NWOYA

NTUNGAMO

BUNDIBUGYO

KALUNGU

KIYUNGA

KAYUNGA

KABALE

AMURIA

MBARARA

KIBOGA

BUDAKA

MASINDI

200 0 200 400 Kilometers

N

LakesDistrict Boundary

Lake Victoria Crescent & Mbale FarmlandsNorthern Moist FarmlandsWestern Medium-High Farmlands

Major Sites Sampled%[ Minor Sites Sampled%[

KEY

Agro Ecological Zones (AEZ)

• Trapping with baited traps• Methyl eugenol • Trimedlure • Torula yeast• Cuelure • Terpenyl Acetate

Collecting mango fruits and other fruits and incubate them to assess fruit fly infestation.

17

Results 1Fruit fly community composition


5 10 15 20

02

46

81

0

sites

sp

ecie

s r

ich

ne

ss

LVC

LVC

NMF

NMF

WMHF

WMHF

LVCNMFWMHF

2 4 6 8 10

1

e+

01

1

e+

02

1

e+

03

1

e+

04

1

e+

05

species rank

ab

un

da

nce

LVCNMFWMHF

LVCNMFWMHF

0 0.25 0.5 1 2 4 8 Inf

0.0

0.5

1.0

1.5

2.0

alpha

H-a

lpha

LVC

LVC

NMF

NMF

WMHF

WMHF

LVCNMFWMHF

Bactro

cera i

nvaden

s

B. curcu

bitae

C. anonae

C. cosyr

a

C. capita

ta

C. fasci

ventri

s

C. rosa

Trithuriu

m coffea

e

Dacus b

ivitatt

us

D.ciliat

us

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

119245

152 339 75 66 5 10 312 956 478

122112

3 401 3 62 0 0 32 2 1

122982

4 272 2 69 12 0 8 485 244

LVC NMF WMHF

18

Results 2Fruit fly community structure


100

22

43 2243 85

22

6485

0.55

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0.95

Sim

ilarit

y

T.co

ffeae

_

C.co

syra

_

B.cu

rcub

itae_

C.ro

sa_

D.biv

itattu

s

D.cil

iatus

_

C.fas

civen

tris_

C.ca

pitata

_

B.inv

ande

ns_

C.an

onae

LVCNMFWMHF

-22-6 5

B.invandens

C.Anonae

C.cosyra

C.capitata

C. fasciventris

C. rosa

T.coffeae

B.curcubitae

D.bivitattusD.ciliatus

-1

1-1 1

P < 0.000

19

Results 3Displacement by B. invadens


0 1 2 3 4 5 6 7 8 9

Rank

-0.8

0

0.8

1.6

2.4

3.2

4

4.8

5.6

log

Abu

ndan

ce

0 1 2 3 4 5 6 7 8 9 10

Rank

0

0.6

1.2

1.8

2.4

3

3.6

4.2

4.8

5.4

6

log

Abu

ndan

ce

0 1 2 3 4 5 6 7 8

Rank

-0.8

0

0.8

1.6

2.4

3.2

4

4.8

5.6

log

Abu

ndan

ce

Conclusion1. At least 10 species in the country but B. invadens is the most widely distributed.

2. Significant diff in richness and abundance of fruit flies but not in evenness and diversity of fruit flies across zones.

3. Differences across zones may be in turn attributed to the inherent environmental and host plant composition.

20











21

STUDY TWO: HOST USE

22

Introduction• Fruit industry provides livelihoods World-wide (Lux et al., 2003; Ekesi and Billah,

2006).

• FF cause variable losses (Lux et al., 2003; Vayssie`res et al., 2005).

• Limited host status knowledge in Uganda, save for regional studies (De Meyer et al., 2002; Copeland et al., 2002; Rwomushana et al., 2008).

• Makes design of mgt options hard (Mwatawala et al., 2009a).

• This study: – To profile the host range of the main fruit fly pests in the three main mango agro

ecological zones; and

– Determine the susceptibility of selected fruits and mango varieties grown to the various fruit fly pests in the country

STUDY TWO: HOST USE

23

Materials and Methods

Three major mango AEZs: WMHF, LVC and NMF (Wortman and Eledu, 1993)

STUDY TWO: HOST USE

1. Intensive collection of commercial and non-commercial fruit hosts.

2. Selected important fruits and mango cultivars in each zone at random sites.

3. Fruits included sweet orange, tropical almonds, avocado, guava and mango.

4. The mango cultivars: Apple Mango, Biire, Boribo, Dodo, Glen, Kagogwa, Kate, Keitt, Kent, Tommy Akinson, Palvin and Zillatte.

5. The 12 cultivars were classified according to their maturity seasonality into early, mid and late maturing cultivars (Ambele et al., 2012).

6. Fruits were transported to the rearing unit at the NARL (Copeland et al. 2002).

24

Results 1Fruit fly Host Range

• 38 fruit species, from 30 genera in 18 plant families were sampled.

• Among these, 633 (35.0%) samples were positive for fruit fly infestation.

• B. invadens was the dominant species: recorded in 29 out of the 38 plant species, while out of the 633 positive samples, 483 (76.3%) were due to B. invadens.

• Host infestation incidence for the rest of the fruit fly species was low

STUDY TWO: HOST USE

Anno

nace

ae

Sola

nace

ae

Ruta

ceae

Anac

ardi

acea

e

Myr

tace

ae

Cucu

rbita

ceae

Mor

acea

e

Sapo

tace

ae

Rosa

ceae

Laur

acea

e

Rubi

acea

e

Cari

cace

ae

Com

bret

acae

a

Ster

culia

ceae

Vita

ceae

Euph

orbi

acea

e

Mus

acea

e

Verb

enac

eae

0

2

4

6

8

10

12

14

16

6 99

9 85 4

3 26 5 4 4 3 2 1 1 1

Plant Richness Fruit Fly Richness

Plant Families

Spec

ies

Rich

ness

25

STUDY TWO: HOST USE

…………………………………………………… ……………………………… ……………… ………………. ………………………………………………………………… ……………………………… ……………… ……………….

……………

26

Results 2:Species Associations

STUDY TWO: HOST USE

Annacardium_occidentale

Mangifera_indica_

Sclerocarya_birrea

Annona_cherimolaAnnona_muricata

Annona_reticulataAnnona_senegalensis

Annona_squamosa

Cananga_odorata

Carica_papaya

Terminalia_catappa

Momordica_charantia

Cucumis_melo_Cucurbita_spp.

Drypetes__natalensis

Persea_americana_

Antiaris_toxicaria_

Artocarpus_sp._

Ficus_sp._

Musa_sp.

Acca_sellowiana

Eugenia_uniflora

Psidium_guanjavaCydonia_oblonga

Prunus_Spp._

Coffeae_arabica

Citrus_limon

Citrus_reticulata

Citrus_sinensis

Citrus_Spp._

Chrysophyllum_albidum

Manilkara_zapota_

Capsicum_annum

Lycopersicon_esculentum

Solanum_Spp._

Theobroma_cacao_

Vitex_sp._

Vitis_vinifera

Bactrocera_cucurbitae

Bactrocera_invadensCeratitis_anonae_Ceratitis_capitata

Ceratitis_cosyra

Ceratitis_fasciventris_

Ceratitis_punctata_Ceratitis_rosa

Dacus_bivittatus_Dacus_cilliatus

Trirhithrum_coffeae_

-300 -240 -180 -120 -60 60 120 180 240 300 360

Axis 2 (38.2%)

-300

-250

-200

-150

-100

-50

50

100

150

200

250

300

350

Axi

s 3

(20.

8%

)

First time infestation of B. invadens on T. catappa, A. toxicaria, E. uniflora, A. selllowiana, Musa spp. and C. Arabica, T. cacao and C. oblonga in Uganda.

27

Results 3

STUDY TWO: HOST USE

Com

bret

acae

a

Anac

ardi

acea

e

Myr

tace

ae

Anno

nace

ae

Mor

acea

e

Cucu

rbita

ceae

Ster

culia

ceae

Sola

nace

ae

Laur

acea

e

Rosa

ceae

Caric

acea

e

Vita

ceae

Sapo

tace

ae

Rubi

acea

e

Mus

acea

e

Euph

orbi

acea

e

Ruta

ceae

Verb

enac

eae

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

Plant Families

Mea

n Po

sitivi

ty (%

)

Term

inal

ia c

atap

pa

Psid

ium

gua

njav

a

Man

gife

ra in

dica

Pers

ea a

mer

ican

a

Citr

us li

mon

Citr

us s

inen

sis

Citr

us r

eticu

lata

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

0

10

20

30

40

50

60

70

80

90

100

B. invadens (%) Overall Positivity (%)

Fruit Species

Pos

itiv

ity

(%)

B. i

nva

den

s (%

)

28

Results 4: Mango Fruit Host Utilization

STUDY TWO: HOST USE

Keitt

Kate

Biire

Glen

Zille

tte

Borib

o

Kago

gwa

Appl

e

Dodo

Palv

in

Kent

Tom

my

0

10

20

30

40

50

60

70

80

05101520253035404550

Mean/ Kg Positive (%)

Infe

stati

on (L

arva

e/Kg

)

Positi

vity

(%)

ALL ZONES

Keit

Tom

my

Kago

gwa

Biire

Dodo

Kent

Borib

o

Palv

in

Appl

e

Kate

Glen

Zille

tte

0

10

20

30

40

50

60

0

10

20

30

40

50

60

Mean Positive (%)

Infe

stati

on (L

arva

e/Kg

)

Positi

vity

(%)

WMHF

Kate

Kago

gwa

Biire

Tom

my

Appl

e

Keitt

Borib

o

Palv

in

Zilla

tte

Glen

Dodo

Kent

0102030405060708090

100

05101520253035404550

Mean/ Kg Positive (%)

Infe

stati

on (L

arve

a/Kg

)

Positi

vity

(%)

LVC

Zille

tte

Biire

Kago

gwa

Appl

e

Dodo

Kent

Glen

Tom

my

Kate

Borib

o

Palv

in

Keitt

0.010.020.030.040.050.060.070.080.0

0.020.040.060.080.0100.0120.0140.0160.0180.0200.0

Mean/Kg Positive (%)

Positi

vity

(%)

Infe

stati

on (L

arva

e/ K

g)

NMF

29

Results 5: Stages of the fruiting season

Early and late season maturing mango varieties were more susceptible.

STUDY TWO: HOST USE

Conclusion• Fruit Flies have a diverse range of commercial and noncommercial or wild hosts in Uganda.

• Tropical almonds and B. invadens were the most suitable host and dominant fruit fly species, respectively. Guava, Mangoes, Avocadoes and Citrus were also favorable hosts.

• Mango varieties varied in their susceptibility to fruit fly infestation within and across zones.

• New fruit fly-host associations were probably due to the adaptive evolution or new records

30

STUDY THREE: PP HYPOTHESIS

Does mother know best?

31

Introduction

• Preference of oviposition vs offspring performance (P-P) is of interest (Bonebrake et al., 2010; Heard, 2012).

• P–P hypothesis: females evolve oviposition behaviors that maximize offspring growth and survival (Thompson, 1988).

• Positive P-P (Rossi and Strong, 1991; Hanks et al., 1993), and negative (Karban and Courtney, 1987; Horner and Abrahamson, 1992) correlations have been recorded.

• Due to the polyphagous nature of B. invadens it was important to assess its relative P-P in the various hosts and mango varieties.

• Hypothesis: Because of its polyphagous nature, B. invadens can obscure the P-P.


32

Materials and MethodsSTUDY THREE: PP HYPOTHESIS

• Lake Victoria Crescent (Wortman and Eledu, 1993)

• Five host plants: sweet orange, tropical almonds, avocado, guava and mango.

• Fruits naturally infested by B. invadens were incubated to determined fruit host preference for oviposition (Aluja et al., 2009).

• Pupae handled as by Copeland et al. (2002), adults as by White & Elson-Harris (1992).

• The adults were sexed and separately weighed.

• Developmental time of development stages was measured as time (days) for each pupae to develop into teneral adult stage.

33

Results 1Fruit host preference for oviposition differed significantly


Tommy

Zillatt

eKeitt Ken

t

Kagogw

aApple

Palvin

DodoKate Biire Glen

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

Mango Varieties

Infe

stat

ion

(Lar

vae/

Kg)

Trop

ical a

lmon

ds

Guav

a

Man

go

Citr

us

Avoc

ado

0

2

4

6

8

10

12

14

16

18

20

Fruit Species

Num

ber

of la

rvae

/ Fru

it

34

Results 2Pupal development too varied significantly 1


12 14 16 18 20 22 24 26 28 30 32 34 360

50

100

150

200

250

TA Citrus Guava Avocado Mango

Cumulative Days

Ad

ult

Em

erge

nce

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 170.00

2.00

4.00

6.00

8.00

10.00

12.00

Apple Biire Dodo Glen Kagogwa Kate KeittKent Palvin Tommy Zillatte

Cumulative Days*

Adul

t Em

erge

nce

35

Results 2Pupal development too varied significantly 2


36

Results 3Adult survival rates varied1


0 10 20 30 40 50 600

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Tropical Guava Citrus Avocado Mango

Longevity (Days)

Surv

ival

dist

ributi

on fu

nctio

n (%

)

0 5 10 15 20 25 30 35 40 45 500

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Apple Biire Dodo Glen Kagogwa Kate Keitt Kent

Palvin Tommy Zillate

Longevity (Days)

Surv

ival

dist

ributi

on fu

nctio

n (%

)

37

Results 3Adult survival rates varied2


38

Results 4Adult weight and sex ratio were significantly higher for TA and least in citrus


39

Results 5P-P was consistent among species but less for cultivars


B. invadens choice of fruit species for female oviposition is guided by preference performance hypothesis. However, among varieties of the same species (for instance mangoes), females tend to maximize their fitness and not necessarily that of offsprings as proposed by the optimal foraging hypothesis!

40











41

STUDY FOUR: INTRASPECIES DIVERSITY

“The millions of species now inhabiting this planet have, evolved from a common ancestor, and the multiplication in the number of species has been generated as single species have split into two.” Darwin

42

B. Papayae Oriental fruit fly

IntroductionIdentity of B. dorsalis complex (>70) is difficult, even with molecular tools (Clarke et al., 2005; Drew et al., 2008).


B. Philippinensis

B. Carambolae

B. Invadens

B. dorsalis/B. papayae/B. philippinensis

B. carambolae

B. opiliaeB. cacuminata

B. musaeB. occipitalis

43

Introduction 2• Variations may lead to biotypes, host or pheromone races with

variable responses to management (Menken et al., 1996).

• Has site and host specific phynotypic variations taken course among B. invadens populations in Uganda?

• This study: – Assess the morphometric variations among three geographic

and hosts B. invadens populations in Uganda.

– Examine fluctuating asymmetry (FA, small random departures from perfect symmetry among individuals).


44

Materials and Methods• WMHF, LVC and NMF (Wortman and Eledu, 1993).

• Terminalia catappa, Psidium guanjava and M. indica.

• Both wings were slide mounted using Canada Balsam. Once dry, photos were taken using a sony camera

• Euclidean distance matrix analysis and variance structure coordinate system geometric techniques.

• Size and shape were analyzed throughout 15

landmarks for 360 specimens after symmetrization.


45

Results 1Host type significantly affected wing size/ shape 1


0.9995

0.9996

0.9997

0.9998

0.9999

1

1.0001

1.0002

1.0003

Almond Guava Mango

Size

-4 -3 -2 -1 1 2 3 4

Axis 1

-2.4

-1.6

-0.8

0.8

1.6

2.4

3.2

4

Axi

s 2

(Blue: Mango; Pink: Tropical almonds; Red: Guava).

46

Results 1Host type significantly affected intraspecific shape variation 2

2


47

Results 2Geographical Variations in Wing Size/ Shape 1


0.9994

0.9995

0.9996

0.9997

0.9998

0.9999

1

1.0001

1.0002

1.0003

WMHF NMF LVC

Size

-4 -3.2 -2.4 -1.6 -0.8 0.8 1.6 2.4 3.2

Axis 1

-5

-4

-3

-2

-1

1

2

3

Axi

s 2

(Blue: WMHF; Pink: NMF; Red: LVC).

48

Results 2Intraspecific Geographical Variations in Wing Shape 2


49

Results 3FA in Zonal and Host B. invadens Populations


Forms of bilateral asymmetry: Fluctuating asymmetry (Mango), Antisymmetry (NMF) and Directional asymmetry (WMHF).

ConclusionB. invadens can exhibit wide phenotypic variations under different envi’tal and host conditions

50



Ecological Niche and Distribution Studies








51

STUDY FIVE: POTENTIAL DISTRIBUTION

“There is no part of natural history more interesting or instructive, than the study of the geographical distribution of animals.” Alfred Russell Wallace (1823-1913)

52

Introduction• Spatial suitability good in the design explicit management strategies for the pest.

• ENM provides an option for potential species distribution.

• ENM allows obtaining range of conditions for species survival/ reproduction (Pearson, 2007; Rubio and Acosta, 2010).

• Prediction model is a function of species response to the environmental variables, hence fundamental niche (Austin, 2007).

• This study: – Determine the geographical regions that are ecologically suitable for fruit fly establishment.

– Explore the climatic profiles underpinning the selected species distribution, to understand their niche requirements


53

Materials and Methods 1• Ten species: B.invandens, C.anonae, C.cosyra, C.capitata, C.fasciventris, C.rosa,

T.coffeae, B.curcubitae, D.bivitattus and D.ciliatus.

• Nineteen (19) environmental variables at 30 arc-seconds (~1 km²) partial resolution were derived from the WorldClim project (Hijmans et al. 2005).

• Models by Maxent and Bioclim (Graham and Hijmans, 2006; Phillips et al., 2006).

• Model evaluation: 75% of the original presence data (training sample), while 25% was test data (Pearson, 2007; Acosta, 2008; Echarri et al., 2009).

• Accuracy of the model was evaluated by calculating the AUC in a receiver operating characteristic plot


Current range prediction

Geographic Space Ecological Space

occurrence points on current distribution

ecological niche modeling

Projection back onto geography

Future range prediction

temperature

Model of niche in ecological dimensions

pre

cip

itatio

n

Current

Correlative Vs Mechanistic Models

Distri. a good indicator of ecological needs Detailed physiological data

STUDY FIVE: POTENTIAL DISTRIBUTIONMaterials and Methods 2

Materials and Methods 3Defining Niches


( )jir e ( ; )j j j

i ix R

( ; )j x T

Grinnell, scenopoetic

Elton, bionomic

MovementsG

BAM Diagram

B

M

A

1( ) ( ; ) ( ; )

jj j j j ji

i i iji

dxr e x x

x dt R T

Fundamental nicheIntrinsic Growth Rate(Scenopoetic)

Resource-consumer dynamics, competitors,predator-prey (bionomic).

Migrationcolonization, history

• Physiological tolerances, migration limitations and evolutionary forces that limit adaptation

• A starting point for abiotic factors is often climate. Climate variables often also correlate with other variables

Environmental Gradient

(Hawkins et al., 2003) 55

56

Results 1Records of Fruit Flies and Potential Distribution 1


Species are diverse and widely distributed!

57

Results 1Bioclimatic profiles of fruit fly species


58

Results 2: Potential DistributionSTUDY FIVE: POTENTIAL DISTRIBUTION

I (D. punctatifrons), II (T. coffeae), III (C. fasciventris), IV (B. cucurbitae), V (D. cilliatus), VI (C. cosyra), VII (C. capitata), VIII (D. bivittatus), IX (C. anonae), X (B.invadens) & XI (ALL).

59

Results 2: Limiting Factors


STUDY FIVE: POTENTIAL DISTRIBUTION: Limiting Factors for selected species

61

Results 2: Limiting Factors


62

Results 3STUDY FIVE: POTENTIAL DISTRIBUTION

Conclusion

• Fruit flies pose a significant threat to the country; countrywide potential distribution of native and exotic species was demonstrated.

• Precipitation and temperature significantly determined distribution.

• Central & mid north zones were most suitable habitats, while the western, north eastern & areas around Albert Nile were marginal.

STUDY SIX: CLIMATE INDUCED RANGE SHIFTS

Projections of Climate-Induced Future Range Shifts among Fruit Fly Species in Uganda.

Charles Masembe, Brian E. Isabirye, I. Rwomushana, A. M. Akol, Caroline K. Nankinga

Journal of Plant Protection Science

“Led by a new paradigm, scientists adopt new instruments and look in new places...” Thomas S. Kuhn (1922-1996)

64

Introduction• Knowledge on geographical suitability of the pest is needed in the design of

spatially and temporally explicit management strategies for pests.

• Global climate continues to change (IPCC, 2007).

• For agriculture, climate change will be significant, as such changes are associated with shifts in pest and disease ranges, posing new risks (Cooper et al., 2013).

• Considerable effort has gone into predicting the effect of future climate scenarios (Walther et al., 2002; Chambers et al., 2005, Shi et al., 2006; McKenney et al., 2007).

• This study: How fruit fly local-level distribution patterns may be expected to change under

future climate change and the comparative potential range shifts among species.


65

Materials and Methods


• Species assessed were: Bactocera invandens, Ceratitis anonae, Ceratitis cosyra, Ceratitis capitata, Ceratitis fasciventris, Dacus punctatifrons, Trirhithrum coffeae, Bactrocera curcubitae, Dacus bivitattus, and Dacus ciliatus.

• Annual mean temperature and mean temperature of wettest quarter were chosen, while moisture gradients were represented by mean annual precipitation and precipitation of coldest quarter.

• Climatic controls on current fruit fly distributions were summarized using the climate envelope (CE) approach (Nix, 1986).

• From the extent of the current CE for each fruit fly species, Future climate variables were generated by two GCMs: HADCM and CCCMA under emission scenarios A2 and B2.

• In the full-dispersal scenario, changes in CE area were calculated by expressing the future CE area as a percentage of the current CE area.

• For the no-dispersal scenario, future maps were overlaid on current maps and only the area of overlap was taken as the future distribution.

• Predicted current and future local species richness and turn over of each of the regions were estimated

66

Results 1Effect of dispersal on future climate envelope size and location


Climate change resilience varied significantly, but Dacus ciliatus > Bactrocera invadens > Ceratitis cosyra pose a serious management challenge as their future habitats are predicted to increase!

67

Results 2Range Shift: Increase


Baseline: 1950-2000 Future: 2000-2050

D. ciliatus

B. invadens

C. cosyra

68

Results 2Range Shift: Decrease


Baseline: 1950-2000 Future: 2000-2050

D. bivittatus

B. cucurbitae

C. anonae

69

Results 3CO2 emission scenarios and species habitat size


Scenario-A2 Scenario-B2

-150

-100

-50

0

50

100

150

200

250

300

Species-B.cu Species-BI

Species-C.ano Species-C.ca

Species-C.co Species-C.fa

Species-D.bi Species-D.ci

Species-D.pu Species-T.co

Carbon dioxide Scenarios

Cha

nge

(%)

Proportional changes in habitat size of predictions under the two carbon dioxide emission scenarios for the 10 fruit fly species and box plots for carbon dioxide scenarios from a 1950-2000 baseline to the 2050 future period.

70

Results 4 Predicted species richness and turnover under the four models and two dispersal scenarios in the three main mango-growing regions.


71

Results 5STUDY SIX: CLIMATE INDUCED RANGE SHIFTS

Conclusion

• Most species are vulnerable and will likely be unable to keep pace with climate change, with habitat losses averaging 25.4% by 2050 future period.

• Fruit fly climate change resilience varied: Dacus ciliatus > Bactrocera invadens > Ceratitis cosyra > Trirhithrum coffeae > Ceratitis capitata > Ceratitis fasciventris > Dacus punctatifrons > Ceratitis anonae > Bactrocera cucurbitae > Dacus bivittatus.

• Dacus ciliatus > Bactrocera invadens > Ceratitis cosyra pose a serious management challenge as range will likely increase

• Future ranges are predicted to shift northwards, mainly to the Northern Moist Farmlands.

72

GENERAL CONCLUSIONS, DISCUSSIONS AND RECOMMENDATIONS I

At least ten tephritid fruit fly species; but B. invadens is the most abundant, and was observed to be displacing the other fruit fly fauna

Difference in zonal faunal composition can be attributed to their (zones) inherent differences in envital conditions, hosts and farming systems.

NMFs recorded lesser alternative hosts for fruit flies, which was converse to the LVC and the WMHF, hence differences in composition

Dominance of B. invadens can be attributed to competition efficiency (Ekesi et al., 2009), and reproduction and resource distribution (Kiesecker et al., 2001).

The LVC offers opportunities for resource distribution, which avoids clumping, converse to the NMFs, which might also explain the difference in displacement pressures between the two zones.

GENERAL CONCLUSIONS, DISCUSSIONS AND RECOMMENDATIONS II

A wide range of hosts was recorded, albeit with significant variability in preference and infestation levels among types, varieties and zones.

Fruits have specific adaptations in their ecological requirements, which ultimately determine their (fruit) susceptibility in their respective environments.

Preference of the flies for the local selection and Kagogwa varieties may be attributed to an increase in performance on these varieties or due to experience or learning (Szentesi and Jermy 1990; Dukas and Bernays, 2000).

74

GENERAL CONCLUSIONS, DISCUSSIONS AND RECOMMENDATIONS III

B. invadens does undergo rapid phenotypic variability which can lead to biotypes, host races, etc…

May lead different populations to adapt and survive in difficult conditions such as the stress caused by control practices and subsequently cause resistance among populations.

The recorded fine-scale intraspecific population phenotypic variations may simply be evidence of phenotypic divergences rather than interspecific differences (Schutze et al., 2012).

Such differences may be irresolvable using techniques such as molecular analysis, hence the current lack of molecular markers to discriminate between these eco- and host types.

75

GENERAL CONCLUSIONS, DISCUSSIONS AND RECOMMENDATIONS IV

The most suitable niches encompass areas around Central and mid north zones, while the western, northeastern and areas around Albert Nile were characterized as marginal.

Current and future niches offer the optimum bioclimatic tolerance limits.

Current and future potential distributions of fruit flies will be determined not only by climate but also dispersal ability, biotic interactions, genetic adaptation, and abiotic factors.

The Ethiopian fruit fly (D. ciliatus), B. invadens and D. ciliatus should be of great concern as range is predicted to increase.

76

GENERAL CONCLUSIONS, DISCUSSIONS AND RECOMMENDATIONS III The ecology of fruit flies needs to be further explored to understand

how community composition evolves in the other landscapes and mgt options.

Habitat suitability maps for these species could be improved by inclusion of edaphic and host plant data.

Further studies on biology of fruit flies in the different edapho-climatic conditions of Uganda are recommended

Achievement of optimum management of fruit flies across farming landscapes is possible, with IPM and area-wide mgt (Ekesi and Billah, 2006; Dyck, Hendrichs and Robinson, 2005).

77

Publications I Refereed Journal Papers

1. Isabirye BE, Masembe C, Akol AM, Muyinza H, Rwomushana I, Nankinga CK (2015) Modeling the Potential Geographical Distribution and Ecological Niche of Selected Fruit Fly (Diptera: Tephritidae) Species in Uganda, Journal of Plant and Pest Science, 2 (1): 18-33

2. Alex Mayamba, Caroline Kukiriza Nankinga, Brian Isabirye, Anne Margaret Akol (2014). Seasonal Population Fluctuations of Bactrocera invadens (Diptera: Tephritidae) in Relation to Mango Phenology in the Lake Victoria Crescent, Uganda. Fruits, 2014, vol. 69, p. 473–480

3. B.E. Isabirye, A. M. Akol, H. Muyinza, C. Masembe and I. Rwomushana, C. K. Nankinga (2015). Fruit Fly (Diptera: Tephritidae) Host Status and Relative Infestation of Selected Mango Cultivars in three Agro Ecological Zones in Uganda. International Journal of Fruit Science. (In Press).

4. B.E. Isabirye, C. Masembe, C. K. Nankinga, A. M. Akol, 2013. Geometric Morphometrics of Geographic and Host-Associated Population Variations of Bactrocera invadens in Uganda. American Journal of Agriculture and Environment.

5. B.E. Isabirye, A. M. Akol, C. K. Nankinga, C. Masembe, I. Rwomushana (2015). Species Composition and Community Structure of Fruit Flies (Diptera: Tephritidae) Across Major Mango-Growing Regions in Uganda. International journal of Tropical Insect science, 1-12.

6. A. M. Akol, C. Masembe, B. E. Isabirye, C. N. Kukiriza, and I. Rwomushana (2014). Oviposition Preference and Offspring Performance in Bactrocera invadens (Diptera: Tephritidae). International Research Journal of Horticulture. IRJH 2014, 2(3): 36-44.

7. Brian E. Isabirye, Charles Masembe,, I. Rwomushana, Caroline K. Nankinga, A. M. Akol (Review). Projections of Climate-Induced Future Range Shifts among Fruit Fly Species in Uganda. Journal of Plant Protection Science

78

Publications II Extended Abstracts

1. Anne Akol, Brian Isabirye, Caroline Nankinga, Charles Masembe and Ivan Rwomushana, 2014. Species Composition and Community Structure of Fruit Flies across Major Mango-Growing Regions in Uganda. 9th International Symposium on Fruit Flies of Economic Importance (ISFFEI).

2. Anne Akol, Charles Masembe, Brian Isabirye, Caroline Nankinga and Ivan Rwomushana, 2014. Oviposition Preference and Offspring Performance in Phytophagous Fruit Flies: The African invader, Bactrocera invadens. 9th International Symposium on Fruit Flies of Economic Importance (ISFFEI).

3. Brian Isabirye, Charles Masembe, Caroline K. Nankinga, I. Rwomushana, Harriet Muyinza, Anne M. Akol, 2014. Projections of Climate-Induced Future Range Shifts among Fruit Fly Species in Uganda. 9th International Symposium on Fruit Flies of Economic Importance (ISFFEI).

4. Brian Isabirye, Charles Masembe, Caroline Nankinga, Harriet Muyinza and Anne Akol, 2014. Geometric Morphometrics of Geographic and Host-Associated Population Variations of Bactrocera invadens in Uganda. 9th International Symposium on Fruit Flies of Economic Importance (ISFFEI).

5. Caroline Nankinga, Brian Isabirye, Mayamba Alex, Harriet Muyinza, Winnifred Aool, Ivan Rwomushana, Philip Stevenson and Anne Akol, 2014. Status of Fruit Fly Infestation of Mango and Other Fruits in Uganda. 9th International Symposium on Fruit Flies of Economic Importance (ISFFEI).

6. B. E. Isabirye, C.K. Nankinga, H. Muyinza, C. Masembe and A.M.Akol, 2012. Effect of Three Host Species on Infestation Levels, Offspring Survivorship, Sex Ratio and Body Weight of Bactrocera invadens (Diptera: Tephritidae). 2nd International Symposium of TEAM.

All of us should be worried about fruit flies as serious

pests, because of their diversity; direct larval feeding on

the host fruit (economic loss); long list of host plants;

flexibility in developing

different life history strategies, including rapid adaptation

to

new habitats; efficient habitat utilization; an ability to

rapidly develop host and geographic races (particularly

true for Bactocera species); and short generation time

(rapid multiplication)

(Brian E. Isabirye, 2015)

Take Home ….

Supervisors:

Mwebale inhoo!!!

“Though the road's been rocky it sure feels good to me.” ― Bob Marley

81

Extras

82

ENM Publication up to 1917-2012

Análisis ecológico del Pleistoceno

Bases de datos, colecciones e inventarios

Biodiversidad

Biogeografía y filogeografía

Cambio climático

Coberturas

Conceptos de especie y subespecie

Conceptos de nicho ecológico

Conservación

Conservadurismo de nicho

Distribución geográfica

Especies invasoras

Evaluación y validación de modelos

Georreferenciación

Importancia de la escala

MNE enfermedades infecciosas

Modelos de distribución y comparación de algoritmos

Sistemas de información Geográfica

Software, guías y tutoriales

0 10 20 30 40 50 60

8

20

24

42

54

9

9

16

53

45

53

23

33

4

9

14

40

11

21