An investigation into the ecology, biology, distribution and control of Haemaphysalis longicornis Neumann, 1901 : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science at Massey University

(1)

Copyright is owned by the Author of the thesis. Permission is given for

a copy to be downloaded by an individual for the purpose of research and

private study only. The thesis may not be reproduced elsewhere without

the permission of the Author.

(2)

A N I N V E S T I G A T I 0 N I N T 0 T H E E C 0 L 0 G Y , B I 0 L 0 G

Y,

D I S T R I B U T I 0 N A N D C 0 N T R 0 L 0

F

H A E M A

P

H

Y

S A L I S L 0 N

G

I C 0 R N I S

N

E

U M A. N N , 1 9 0 1 .

A thesi s presented i n par t i al fulfilme nt of the requ ireme n t s for the degree of Master of Ve terina& Sci ence at

Massey Uni versi t y .

Fre deri ck Jame s Alexander Ne i l son B . V . Sc .

1 980

<J

(3)

A B

S

T

R

A C T

In

1 974 ,

que s t i onnai r e s were di stribute d t o farmer s i n the Eas t Coast and Hawke� Bay areas of the Nor th Island of

New Zealand . The t i ck Haemaphysalis longi corni s Neumann

1 90 1

was pre sent on

59%

o f farms i n the East Coast-Nor thern

Hawk�s Bay are a and

7%

of farms in the remainde r of t he Hawke�

Bay are a . In the former area the t i ck appeare d to have spread rapidly be tween

1 96 4

and

1 974 .

In the East Coas t -Nor thern Hawkes Bay are a , approx imately one third of all farme r s consi dere d that the t i ck was a

signi f i cant prob lem on their farm . In t he Cen t ral and Sou t hern Hawk�s Bay are a the t i ck was not conside r e d a problem and

cond i t i ons were probab ly margi nal for t i ck surv ival .

The di s tribution o f the t i ck was relate d to temperature , rainfall and alti tude . Almo st all farms where t i cks we re pre sent were si tua t e d at less than 300 me tres above sea leve l .

The d i s tribution o f t i ck counts of she e p were posi t i vely

skewed and i t was s hown that the data should be normalized b y transforming t o logari thms or square roo t s . S quar e roo t s repre sent the easi e s t me thod o f transformat ion .

A compar i son b e t we e n t i ck counts of the l e f t ear , r i ght ear , b o t h e ars and the b ody , showe d that overall ear counts

cont r i bu t e to nearly 50% o f t he to tal t i ck count . Howeve r , the propor tion o f t i cks on t he ears compare d wi t h on the b ody var i e d over the count ing period and e ar counts were not hi ghly c orrelated w i t h body coun t s ( highe s t c or re lat i on , r

⁼ 0 . 38 ) .

The d i amide , ami tra z , showe d a hi gher i n i t ial e f f i cacy

against H . longi c orni s compared wi th Chlorfenv i nphos , but the lat t e r appeare d to have a longer period of re sidual act

i

v i t y .

i i

(4)

0

In t he Northern Hawke� Bay and Eas t Coas t are a most

(�4%)

she e p owners dip be twe en January and March and over half

( 54%)

dip i n January o r March and t h i s period does no t coincide w i th the adu l t and larva l peaks .

Inc reasing she ep numbers from

3

per

1000

m2

(

equi valent to

30

per hec tare

)

to

3

per

500

m 2

(

e quivalent to

60

per he c tare

)

re sul ted in lower t i ck survival in the more heavily s tocked are as .

An examinat ion of the water balance of t he unfe d s tage s showed that larvae were very susce p t i b le to de s i c cation at humi di t i e s be low

80%

R . H . Adu l t s we re more re si stant to desiccation than nymphs . Larvae and nymphs re gain water rapi dly af ter

de siccati on . The cri t i cal e quilibrium a c t i vities for the unfed s tage s was found to be approximately

0 . 8 , 0 . 7

and

0 . 9

for

larvae , nymphs and adu l t s re spe c tive l y .

Immersion of unfed and engorge d stage s i n water indi cated t hat t he former survive i mmersion for � 1 8 days whi le t he latter showed lowe r survival .

Evidence i s pre se nted to sugge st H. longi corni s can cause deaths from anaemia i n young Re d De er .

i i i

(5)

A C K N

0 W

L E D G E M E N T S

The i nv e s t i gations reported in this the s i s were carried ou t f rom

1 9 74 - 1 980

whi le the author was a ve terinary offi cer wi t h t h e Mini stry of Agri cul ture and Fi sheri e s . Some experimental work was carried out at Wallaceville Animal Re search Centre and t he remainder on farms in the Eas t Coast and Hawk�s Bay are a .

I

am grateful to t he dire c torate ( Dr G . Adlam and

Mr

R . Sali sbury ) and t he regional ve terinary offi cer

(Mr E . H . Shortri dge ) o f the Animal Heal t h Divi sion , Mini stry of Agri culture and Fi sheries , Ne w Ze aland , for permi ssion for this work to be under t aken and for arrangi ng study leave .

I am i ndebted to Dr W . A . G . Charleston and Dr A . C . G . Heat h who superv i se d the rese arch and provided valuable advi ce ,

cri t i c i sm and encourageme nt throughou t t h i s study .

I wish t o express my thanks to all past and pre sent staff of the Animal Heal t h Div i sion , M . A . F . from Gi sborne , Wairoa and Rua toria who ass i s t e d wi th fenc ing and t i c k counting . To Messrs R . de Bors t and M . Venni ng who also ass i s ted with t i ck coun ting , my grate ful thanks . Mr G . B . Dav i s collated the tick questi onnai roofrom the central and sou thern Hawk�s Bay are a and I wish to acknowledge and thank him for this

assistance .

Farmer s i n the Gi sborne are a also ass i s t e d wi th thi s study and I would like to t hank Mr J . Wilson and Mr W. Condor .

As well

I

am i ndeb t e d to Mr John Holdswo r th , Waikohu Station , who provided s taff and 'ac i l i t i e s , over a considerable peri o d , for mustering and spraying sheep and hol d i ng sheep for t i ck count s .

I w i sh to thank Dr A . Heath for arranging the use of fac i li t i e s

v

at Wallacevi lle and for hi s collabora t i on wi t h Mr L . M . Morri son in the statisti cal analysis of the t i ck c oun t s from the

i nse c t i c i dal expe riment .

iv

(6)

V

I also appr e c i ate the assi stance o f the se ni or supervi sor ,

Dr Charles ton , for hi s adv i ce on the pre s e nt a t i on of t hi s thesi s .

Fi nal ly , t o Mr s A . WiRepa , my hear tfe lt thanks for typ i ng t he dra f t and f i nal copy o f thi s thesi s .

F . J . A . NEILSON

De cember,

1 980

(7)

PRE F A C E

Be t we e n 1970 and 1 974 the range and pre valence o f

Haemaphysal i s longi corn i s appeare d to b e i ncreasing o n farms i n t h e Eas t Coast and Nor t he r n Hawkes Bay are a . Be cause o f thi s appare nt incre ase i n t i ck numb e r s a ce nsu s was p o s t e d t o farmers in t he area wi th t he a i m of mappi ng t i ck d i s t r i b u t ion . The n b y a p roce ss o f i nduc t i ve re asoning i t was hope d t o exam i ne var i ou s fac tors that mi ght i nf lu e nce this di s tribu t i on. The Central Hawke� Bay area was i nc luded i n t he census a s o nl y a f e w t i cks had been reported from t hi s are a .

Some farme r s i n the Eas t Coa s t and Northern H . B . area considere d t h a t the t i ck was e conomi cally i mportant so se l e c t e d farm

prac t i c e s (e . g . s tocki ng rate , t i me o f dipping or showe ring , c h o i c e of i nse c t i c i de) were i nve s t i gated as i t was hoped t h i s m i gh t prov i de i nforma t i o n o n whi ch re commendat i o ns f o r the control o f the t i ck could be base d .

Wat e r balance i s e sse n t i al for the surv ival of all animal spe c i e s but i t is cru c i al to t he exis tence of t i cks be cause of the ir surface to vo lume r a t i o . As the wa t e r rela t i o ns o f e ggs and e ngorge d s tage s o f H . longi corn i s have bee n thorough ly i nve s t i ga t e d (Heath , 1 974 ) so i t was d e c i d e d to i nves t i ga t e t h i s relat i onship in t h e unfed s tage s . It was hop e d that thi s m i ght lead t o a b e t t e r unde r s t anding o f the survi val and he nce t h e d i s tr i b u t ion o f t h e t i ck .

"The t i ck i s ge nerate d f rom c ouch grass ."

Ari s to tle i n Historia Ani mal i um , c i r ca 300 B.C.

vi .

"Af ter trea tment t he r e w i l l be no sore s and the wool wi l l be more plenti fu l and in be t te r cond i t i on and the r i ci ni ( t i cks ) w i l l no t be troub le some" .

M .

Por c i u s Cata 200 B. C .

(8)

T A B L E 0

F C

0 N T E N T S

Abst rac t

Acknowle dge ments Pre face

1 . Re view of the li tera t ur e 1 ^•1

1 . 2 1 . 3

Ge neral introd uc t i o n Taxo nomy o f t i ck s

The ge nus Haemap h ysal i s

1 . 4 Taxo nomy of d i s t r i b u t i on o f Hae maphysali s longi c orni s

1 . 6

Morpho logy of t i cks 1 .5 . 1

1 .5 . 2

General

Morpho logy o f H. longi corni s Ge ne t i cs of H . longi c orni s

1 . 7 Introduc tion o f H. longi c orni s i n t o New Ze aland and Au stralia

1 . 8 The e s tabli shme n t , spre ad and pre se nt

Page i i i v vi

1 2 4

5 1 1 1 1 1 2 1 6 1 9

di s t r i bu t i o n o f H . longi c orni s i n New Ze aland 23 1 . 9

1 . 10 1 . 1 1

1 . 1 2

Ti ck fauna o f the Ne w Ze aland sub-regi o n

The s i gni fi cance and e conomi c import ance o f t i cks 1 . 1 0 . 1

Biology 1 . 1 1 . 1 1 . 1 1 . 2 Ec ology

1 . 1 2 . 1 1 . 1 2 . 2 1 . 1 2 . 3 1 . 1 2 . 4 1 . 1 2 .5

1 . 1 2 . 6

The s i gni fi cance o f H . l ongi corni s o f t i cks

Bio logy of H . longi corn i s Se asona l i t y o f H . l onsi corni s of t i cks

The t e mperature r e la t i ons of t i cks Tempera ture re lati ons o f H . longi c orn i s The wat e r re la t i on s o f t i cks

The wat e r re lat i ons of H . lo ngi corni s The i�f luence o f vege ta t i o n o n the

surv i va l , act i v i t y , d e ve lopme n t and d i stribu t i on of t i cks

The i n f luence of vege ta t i o n o n t he survival , deve lopmen t a c t i vi t y and d i s t r i bu t ion of

H .

longi co rn i s 1 . 1 3 Hosts of H . l o ngi corni s

26 27 30 33 39 43 48 48 50 56 63

67

70 75

vii .

(9)

1 . 1 4 The c o n trol of t i ck s

1 . 1 4 . 1 The c on tro l of H . longi corni s

Exp e r i me ntal Se c t i o n 2 .

3 .

Ti ck que s t i onnaire 2 . 1 Introdu c t i on

2 . 2 Mate r i al s and me t ho ds 2 . 3 Re su l t s

2 . 4 Di scus s i on

Ti ck coun t i ng . Di s t r i b u t ion o f t i ck s counts o f she e p 3 . 1 In tro d u c t i on

3 .2 Mat e r i al s and me thods 3 . 3 Re su l t s

3 . 4 Di scussion

4 . Ti ck count i ng: the re la t i onshi p be twe e n ear and body c ounts of H . longi corni s on she e p

4 . 1 4 .2 4 . 3 4 . 4

Introduct ion

Mat e r ials and me thods Re s u l t s

Di scuss ion

5 . Exam i nat i o n of ind ivi dual t i ck coun ts from she ep for evidence of resist ance to i nfe s t a t i on

6 .

5 . 1 Intr oduc t ion

5 . 2 Mat e r i als and me t hods 5 . 3 Re sul t s

5. 4 Di scussion

Chemi cal con trol o f H. longi corni s on she ep:

Compari son o f the e ff i cay o f two i n se c t i c i d e s 6. 1

6 . 2 6.3 6 . 4

Intr oduc t ion

Mate r i als and me thods Re su l t s

Di scussion

7 . Chemi cal c on trol of H . longicorni s: i nforma t i on from the Ne w Ze aland Sheep Re turns on the me thod a nd t i m i ng o f dippi ng i n the Eas t Coast Northern Hawkes Bay are a

7. 1

f

ntr oduc t i on

7 .2 Mat e r i als and me thods 7 . 3 Re sul t s

7 . 4 Di scussion

v i i i .

Page 77·

79 8 4 84 84 8 4 86 9 4 109 109 1 09 1 10 1 1 8

120 120 120 1 2 1 126

128 128 1 28 1 30 1 30 1 33

1 33 1 33 1 35 1 38

1 40 1 40 1 40 1 40 142

(10)

8 . The i nfluence o f stocking rate on t i c k survival 8 . 1

8 . 2 8 . 3 8 . 4

Introdu c t ion

Materials and metho d s Re sul t s

Di scussion

9 . The water b alance of unfed larvae, nymphs and adults

10 .

of H . longi corni s

9 . 1 Introdu c t i on

9 . 2 Mate r i al s and me thods

9 . 3 Re sul t s

9 . 4 Di scussion

The effe c t s o f immer sion in wat er on H . longicorni s 1 0 . 1 In trodu c t i on

1 0 . 2 1 0 . 3 10 . 4

Ma t e r i als and me t hods Re sul t s

Di scussion

1 1 . S ummary and c onclusi ons Appe ndix

1 . Copy of the que st ionna i re posted to farmers in Decemb e r . 1 974

2 . P ho t ograph of a map of the locat i on of f armer s in the Cook County who rep l i e d t o t he 1 974 que s t i onnaire 3 . Pho t ograph of a map of the locat i o n of farmer s i n the

Page 1 43 1 43 1 43 1 43 1 44

1 46 1 46 1 4 7 1 50 1 59 1 63 1 63 1 63 164 1 67 1 70

1 73 1 76

Waikohu Coun t y who repl ied to the 1 974 ques t i onnaire 1 77 4 . Pho tograph o f a map o f t he locat i o n of f armer s i n the

Wai apu Count y who repl i e d t o the 1974 que s t i onnaire 5 . Pho tograph of a map o f t he lo c a t i o n of f armers in t he

1 78 Wai roa County who repli e d to t he 1 974 ques t i o nnai re 1 79

(;

ix

^•

(11)

App e nd i c e s 6 t o 30 are t i ck counts of sheep refe r r e d t o i n Se c t ions 3 , 4, 5 , 6

6 . 7 . 8 . 9 . 1 0 . 1 1 . 1 2 . 1 3 . 1 4 . 1 5 . 1 6 . 1 7 . 18 . 19 . 20 . 2 1 . 2 2 . 23 . 2 4 .

25 . 2 6 . 2 7 . 1 8 . 2 9 . 30 . 3 1 . 32 . 3 3-

Ti ck coun t s of A0 .03

" "

" ^"

" "

"

" "

" ^"

" ^,,

" ^"

" "

" ^"

" "

" ^,,

" "

" ^"

" "

" A0 .05

" ^"

" "

" so .o6

" "

" ^"

" "

" Control group

" "

" ^"

" "

" ^"

day

"

11

"

11

"

'"

"

0 and day 7

"

1 3

"

27

"

0

"

1 3

"

27

"

0 0 1 3

"

2 7

"

0

"

1 3

"

27

"

,,

"

20

"

34

"

7

"

20

"

34

"

7 7 20

"

7

" "

" 20

" "

" ^"

" 34

" ^"

" "

A naemia and deaths i n Red De e r assoc iate d w i t h heavy i nfe s tat i ons of H. longic orni s

Bib l i ography

x.

Page,

1 80 1 8 1 182 1 83 184 1 85 1 86 1 8 7 188 1 89 1 90 1 9 1 192 1 93 1 94 195 196 1 9 7 198

1 99 200 20 1 202 203 204 205 206 207 2 1 1

(12)

Table

1 . 1 1 . 2

1 . 4 1 . 5

L I S T 0 F T A B L E S

T axonomic relat ionsh i p s of t i cks

World di s t r i b u t ions of H. longi cornis and H. b i spi nosa

Compar i so n of H. longi c orni s and H. b i sp i nosa Approximate size range s o f H. longi corni s Field and l aboratory d a t a o n t he b i o logy o f H . longi c orni s

1 . 6 Proposed relat ionship b e t we e n t e mp e rate and b i o logy of H. longi corni s

1 . 7 Di stri but i o n of H. longi corni s i n Ne w Ze a land and Australia in relat i o n t o cli ma t i c ind i ce s

1 . 8 Soil te mpera ture and wa ter measureme nts i n t he e nvi ro nme n t of ryegrass and paspalum pas t u re s 1 . 9

1 . 1 0

Hosts of H. longi corni s

Summary of i nse c t i c i d a l trials agai ns t

xi

Page 3

9 1 0 1 5

40

5 1

55

74 76

H. longi corni s on c a t t le and she ep i n New Zealand 8 1 2 . 1 Length of t i me H. longi corni s pre sent on farms i n

t he Northern H. B. and Eas t Coas t are a

2 . 2 Alti tude, rainfall and annual mean tempera t u re s for t he Climato logi cal S t a t ions in the are a m ap p e d for t i ck d i s t r i b u t ion

3.1 Chi-squar e d value s from t e s t i ng goodne ss o f f i t o f ac tual t i ck counts t o a normal d i s t ribu t i o n

Chi-squared value s f r o m t e s t i ng goodne ss o f f i t o f ac tual t i ck count + 1 t ransformed to logar i t hms t o a normal d i stribu t i o n

8 7

1 0 0

1 1 7

(13)

xii

Table Page

3 . 3 Chi-squar e d values from t e s t i ng goodne ss o f f i t o f ac t ual t i ck counts trans formed t o square roo t s t o a normal d i stribu t i o n

4 . 1 Compar i son by ANOVAR o f le f t, right and comb i ned ear cou n t s and body c o u n t s of 302 sheep o n day 0 4 . 2 Compar i so n by ANOVAR o f t o tal le f t , r i ght and

c o mb i ne d e ar coun t s and body cou n t s o f t i ck s from 98 sheep o n days 0 , 7 , 13 , 20 , 2 7 and 34

Compar i so n b y ANOVAR o f comb i ne d e ar coun t s wi th body count s of 98 she e p o n days 0 , 7 , 1 3 , 2 0 , 27 and 3 4

4 . 4 Ear and body counts o f t i cks at i nd i vi dual

4 . 5

observa t i o n t i me s f o r all untre a t e d she ep

Correla t i on be tween c ombi ne d ear and body counts 5 . 1 Cumula t i ve freque ncy d i s t ribu t i o n of t o t a l t i ck

c ou n t s of 302 shee p o n day 0

5 . 2 ANOVAR of t i ck count s o f sheep whi ch had b e e n ass igned t o one of 3 groups o f t he bas i s o f t he i ni t ial t i ck count

6 . 1 A NOVAR of t o t al t i ck c o u n t s for days 0 , 7 and 1 3 f o r 3 t reatme nt group s and a control group

6 . 2 A NOVAR o f t o tal t i ck c o u n t s for days 20 , 2 7 and 34 for 3 treatment group s and a control group

7 . 1 Mai n d i p p i ng me t hod o n farms i n the Eas t Coas t and Nor thern H.B. area

7 . 2 Mon th o f d i p ping nomi na t e d b y She e p-owner s i n t he Sas t C�a s t and Nort he r n H.B. area

1 1 8

1 2 1

1 22

1 2 3

12 4 1 2 5

1 2 9

1 3 1

1 3 6

1 37

1 4 1

1 42

(14)

Tab l e

8 . 1 8 . 2

Nymphal count� of she e p i n paddocks A , B, C and D Adu l t count s o f sheep i n p addo cks A, B, C and D 9 . 1 Me an we ight c hange s of u nfed larvae, nymphs and adu l t s of H . longi corni s de s i c c ated for var yi ng pe r i ods

1 0 . 1

10 . 2

3 3 .1 3 3 -2

Effe c t of immersion i n wa ter on e ngorged s tage s of H . longi corni s

Effe c t of imme r sion i n wa ter on u nfed stage s o f H . longi c ornis

H ae mato logi c a l exam i na t i o n of 4 fawns

Normal value s for c e l l u lar consi tue n t s of Red De er

xiii

Page

144 14 4

1 50

1 66 208 209

(15)

xiv

L

I S T 0 F F I GURES

F i gure

1 . 1 Wor l d d i s t r i b u t i on of H . l ongi c or n i s and H . b i sp i nosa 7 1 . 2 H . l ongi c or n i s f r om c a t t le - i nfe r t i le ma l e 1 3 1 . 3

1 . 4 1 . 5 1 . 6 1 . 7

11

Di s t ri b ut i on L i f e c y c l e o f

11 " - s l i gh t ly e n gor ge d female

11 " - nymph

" " - l a r va

of H . l on �i c or n i s w i t hi n Ne w Ze a l a n d i x od i d t i ck s

1 . 8 Di agramma t i c a l re pr e se n t a t i on of t he seas ona l i t y of H. l ongi c or n i s

1 . 9 S e a s onal d i s t r i but i on of p re c ip i t a t i on ex c e e d i n g 50 mm

1 . 10

1 . 1 1

1 . 1 2

pe r mon t h

The range o f t e mpe r a t u r e s a n d s a t ur a t i on de f i c i t s f a vourab le f or survi va l a n d de ve l opme nt of n on paras i t i c s t a ge s of H. l ongi c orn i s

Cumula t i ve we i ght l os s of e ggs and e ngorge d s tage s of H . l ongi c orni s e x p os e d t o d r y a i r at 2 5°C

R ange of t e mp e r a t u r e a n d re l a t i ve humi d i t y f ou n d t o b e f a vourab l e f or t he e ggs , e n gor ge d lar vae a n d nymphs of H . l ongi c or ni s

1 . 1 3a Pe r c e n t age of i mpr ove d l a n d c on t a i n i ng p a s p a l u m i n t h e pas t ure

1 3

1 4 1 4

2 4 38

44

4 6

5 2

6 5

6 6

72 1 . 1 3b Pr op or t i ona t e change i n p aspalum c on t e n t 72 2 .1 App r ox i ma t e are a of d is tr ib ut i on of q ue s t ionn a i r e 8 5 2 . 2 Op i ni on s of farme r s i n t h e Eas t C oa s t and N or t he r n

H.B. as t o t he si gn i f i c a n ce o f H. l ongi c or n i s 8 7

(16)

Figur e Page

2 . 3 Di s tribution o f farms in Ce n tral

H . B .

on which t i cks were reported to be pre se n t

2 . 4 A r e a from whi c h rep l i e s t o the que s t i onnai re were r e c e ive d by the Gi sborne offi ce of t he M .A . F . 2 . 5 Distribution of prope r t i e s on whi c h no ti ck s we re

r e p o r t e d to be pre sent

2 . 6 Di s tribution of prope r t i e s on t i ck s we re pre sent but not considered a problem

2 . 7 Di s trib u t i on of proper t i e s where t i cks wer e pre se n t a n d c ons idered a prob l e m

2 . 8 Mean rai nfa l l and rai n f a l l for Nove mber, De c e mb e r January and Fe bruary ( Manu tuke Cl imat ologi c a l S t a t i o n )

2 . 9 Mean tempe rature and t e m p e ra ture for June, Ju l y, Augu st and Sep tember ( Manu tuke Clima t ologi cal S t a tion)

2 . 1 0

2 . 1 1 2 . 1 2

2 . 1 3

3. 1 3. 2 3-3 3. 4 3-5 3. 6

Clima tologi cal Stations i n .the are a in whi ch t i ck dis tribution was mappe d

Mean annual rainfall i n C e ntral and Sou the r n H.B.

Soil t ype s o f Cook, Wai k o hu , Wair oa and Wai apu Cou n t i e s

Mea n annual rai nfall i n t he Eas t Coast and Nor thern

H . B .

are a

Freque ncy di stribu tion o f tick c o u n t s - d a y 0

" " " " " " 7

" " " " " " 1 3

�

" " ,, " " " 2 0

" " " " " " 2 7

" " ,, " " " 34

8 8

9 0

9 1

92

9 3

9 8

9 9 1 0 2

1 0 5

1 0 6 1 1 1 1 1 2 1 1 3 1 1 4 1 1 5 1 1 6

XV

(17)

Figure

9. 1 a M e a n we i ght change s o f une ngorge d l arvae of H. l ongi corni s d e s i ccated for 4 hours the n

xvi

t rans ferred t o 6 d i fferent R .H . 's 15 1 9 . 2a & 9 . 2 b Me an we i ght change s of unengorged nymphs of

9.3a

9 . 3 b

9-5

9 . 6

H . longi corni s d e s i ccated for 28 hours t hen trans f e rred t o 6 d i fferent R .H .'s

Me an we i ght change s of unengorged ffema l e s o f H . longi c orni s d e s i c c a t e d f o r 24 ho ur s the n transferred t o 6 d i fferent R .H . 's

Me an we i ght change s of une ngorged femal e s of H. longi corni s d e s i c cated for 48 hou r s the n

tran s f e rre d to 6 d i ffere nt R .H . 's

Regr e s s i o n of % change i n p o s t-de s i c c a t e d b o d y we i gh t o f unfe d H . longi corni s larvae on R .H . %

Re gr e s s i on of % change in p o s t-de si c c a t e d body we i ght o f unfe d H . longi corni s nymphs on R .H . %

Regr e s s ion o f % c ha nge i n pos t-de s i c c a t e d body we i gh t of unf e d H. longi c orni s female s o n R .H . %

,.

152

1 5 3

1 56

1 5 7