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ECOLCGICAL CHARACTERIZATION OF CYTOTYPES OF THE SIMULIUM PENUSTUMIVERECUNDUM COMPLEX (DIPTERA: S I W L I I D A E )

FOUND ON 'PHI AVALON PENINSUWL. NEWFOUNDLdND

b y

@JOHN WILLIAM McCREADIE, B.SE., M.SC.

A T h a s i s s u b m i t t e d t o t h e S c h o o l of G r a d u a t e S t u d i e s i n p a r t i a l f u l f i l m e n t of t h e r e q u l r e I n e n t s for the d e g r e e o f

mEtor o f ~ h i m s o p h y

D e p a r t m e n t of B i o l o g y M e m o r i a l U n i v e r s i t y of N e w f o u n d l a n d

n * ~ ^3;tg~;mw

mlinwue naimac d" CaMdS CaMdian meres Ferv4a Servica dos ,"ha% -"a*- a,rr=. Cam*

r, non4

me author has pranled an ineMcable now Cauteur a accord4 une lfconce m8m?blc c l B X O I U S ~ ~ I oenm Bn0ws-g Ihe Nahod U b w "on exduo,va pemwtlant I la B~hlnlhCquc 01 Canada 10 mpmducc. h, dlsmbdlo or wil nabnalc du Canada de rcDrodare. nrolor.

copies of hisher thesis by any means and in dismbuer ou vendre des copies de w lhbso any farm arfwmat, m l n g l h k l h e s i s a ~ e de quelque .nani&re el sous queique lame to interested persons. que ce sail pour melire des exemoialrcs do cette lhbso B la disposition dos pcmonncs int&rcss&es.

The aulhor retains ownenhip of the copyrighl Cauter -serve la pmpri6tbdu dm41 d'auleur in hislher thesis. Neither the thesis nor qui prolbge sa t h h . Ni $ th&se ni dcs exlmits subslantiai exlracta from it may be printed or substanlielo de ceiioci ne doivonl Btrc otherwise reproduced wilhaul hislher per. imprimCs au aulremenl rcpmduils wns son

mission. aulorisalion.

The S. venuetuq/verecundum complex ( ~ v a l o n P e n i n s u l a , Newfoundland) was examined t o a s c e r t a i n i f i n d i v i d u a l c y t o t y p e s had u n i q u e and p r e d i c t a b l e e c o l o g i c a l c h s r a o t o e i s t i c s . Emphasis was p l a c e d o n l a r v a l s p a t i a l - temporal d i s t r i b u t i o n . sir c y t o t y p e s were found: EI'GIC vanusturn, CC2-3

xelxstm

(oombined cc2 and cC3). AC(9b) vanusturn, AA verecUnduIR and ACD verecundum.

L a m a 1 c y t o t y p e s s e l e c t e d d i f f e r e n t m a c r o h a b i t a t s . E F C I C and ACO were s u b l a c u s t r i n e s p e c i e s ; CC2-3 a n d AC(gb) p r e f e r r e d downstream s i t e s . Within downstream h a b i t a t s CC3 u s u a l l y occurred i n l a r g e s t r e a m s and AC(gb) In a o o l c a n o p i e d s i t e s v z t h a bed of s m a l l s t o n e s or r u b b l e ; CC2 wss u b i q u i t o u s . AA p r e f e r r e d c u t l e t s and t r i c k l e s . c y t o t y p e fauna changed i n a c o n t i n u o u s , d i r e c t i o n a l and p r e d i c t a b l e manner w i t h i n c r e a s e d d i a t a n o e from o u t l e t s .

Abundance o f CC2-3 i n c r e a s e d w i t h i n c r e a s i n g s e s t o n and- d i s c h a r g e , and d e c r e a s i n g c o n d u s t i v i t y . Ac(qb) abundance i n c r e a s e d w i t h i n o r e a s i n g s t r e a m width.

L a r v a l o y t o t y p e s a l s o s e l e c t e d d i f f e r e n t m i c r a h a b i t a t s . o p t i m a l v e l o d t y f o r EFGIC end ACD war 0.36 a n d 0.71 rota, r e s p e c t i v e l y . EFG/C p r e f e r r e d s h a l l o w w a t e r b u t ACD showed no d e p t h p r e f e r e n c e . Tbese d i f f e r e n c e s were n o t r e l a t e d t o l a r v a l s i r e . Maximum abundanse of EFG/c o c c u r r e d 10.5

-

^{16.0 m from}

o u t l e t s ; AcD was m o s t abundant j u s t below o u t l e t s .

iii Proportionally more ACD and AA were found on vegetation than rooks; the reverse was true for EFGIC. The density of ACD and AA was higher on vegetation than rooks.

Seasonal occurrence of cytotypes overlapped but population peaks were typically asynchronous. EFGlC appeared 1

-

5 weeks earlier than other cytotypes. ACD and M appeared later and remained longer than other cytotypas. EFG/C was univoltina. Ac(gb) may have a limited second generation. CC2-3 was bi- or multivoltine. ACD and AA were multivoltine.

EFG/C complete larval development from 5

-

3 O D C with maximum survival between 15

-

^2O0C ( 6 8 . 0

-

^73.5%). An A C D - M mixad population completed development between 5

-

^{25-C with}

maximum survival between 15

-

25-C (55.3

-

6 1 , 0 1 ) . The temperature survival curve of EFGIC was significantly different from ACD-M. Threshold temperature was O'C. Degree- days t o complete larval development varied with temperature, oytotyps and sax. Temperature also affootad larval size.

It was concluded that each cytotype examined was a distinot spesies with a unique and predictable ecological profile, supporting the hypothesis of widespread sibling speciation within the ~/mc!m&S. wx oomplex.

First and foremost I wish to express my sincere thanks to my supervisor, Dr. Murray H. Colbo. Not anly did he provide the means to make this study possible, but more importantly he always found the time to help. I also vish to thank tha other members of my supervisory cornittee, Drs. Allan Whittisk and John 'Picko Pickavance for their invaluable assistance throughout thin project. My thanks are also extended to Ray Fereday and the late Dr. Klaus Rothfels, University of Toronto, for teaching me the art of cytotaxonomy.

I would also like to express my appreciation to the following individuals ior their contribution to this project:

Dr. Graham Skanes for his statistical advice;

ROY Picken for his photographic assistance:

Arthur Dent and Ford Perfect for their constant source of inspiration.

My sincere thanks are extended to Ludwig 'Papa' Cubler whose financial support during the writing phase of this project will always be remembered.

Finally, I wish to dedicate this theses to my wife Edith GublerMcCreadia for her unlimited encouragement, patience and support. This *ill never be forgotten.

TABLE Of CONTENTS

ABSTRACT

...

ⁱⁱ

...

ACKNOWLEDGMENTS i~

...

LISTOFTABLES x LISTOFFIGURES

...

^Xiv

...

CHAPTER 1

.

GENERAL INTRODUCTION 1 OBJECTIVES

...

3

...

REVIEWOFRELEYANTLITERATURE 4

...

S i m u l i i d l i f e h i a t o r y 4 s p a t i a l d i s t r i b u t i o n p a t t e r n s of p r e i r n a q i n a l s i m u l i i d s

..

9

H v d r o d v n a n i c s o f f l O W

. . ...

¹¹

T c m p e r s t c r e

...

13

The m u l ~ u m v q ~ l ~ l v e r e c u n d ~ n s

.

1

.

complex

...

¹⁴

s~mu!i;d ~ a x o n o n y

...

17

Cyro:ogy of t h e

w

venulrunlverecundun e o n p l e u

...

¹⁹

THESIS FORMRT

...

²²

...

CHAPTER 2

.

GENERAL ITETHODOWGY 36

...

S t u d y area 3 6 C y t o t a ~ o n ~ m i ~ p r o c e d u r e 8

... ...

³⁸

Measurements of s t r e a m c o n d i t i o n s 39

...

c o n d u c t i v i t y . pH a n d d i s s o l v e d oxygen 3 9 Water t e m p e r a t u r e S e s t o n

... ...

⁴⁰ 40

...

s t r e a n bed, r i p a r i a n v e g e t a t i o n and canopy cover 40

...

s t r e a m v e l o c i t y . d e p t h a n d width 4 1 L a r v a l r e a r i n g p r a c e d u r e s

...

^{4 1} H e a d c a p s u l e m e a 9 u r e m e n t s

... ...

⁴²

GeneralstatieticalproCedUrB5 43 CHAPTER 3

.

CYTOTYPE FAUNA OF THE AVAWN PENINSULA

...

4 8 INTRODUCTION

...

⁴⁸

MATERIALSANDMETHODS

...

^{4 8} RESULTS

...

⁴⁹

EFGlC

...

⁴⁹

cC2 andCC3 venurtum

...

4 9

"1 A C ( 9 b ) Yenustu... 5 0

...

AA yerecundurn 51

ACD YBrec~ndun

...

5 1 DISCUSSION

...

⁵²

EFGIC

xc!x&m ...

⁵²

CC2 XQU&W and CC3

...

⁵³

A C ( g b ) xsa!&2m

...

5 5

...

AA verecundun 5 ~

ACD Y e r e ~ U n d U m

...

5 6 S m Y

...

5 7 CHAPTER 4

.

THE INFLUENCE OF TEMPERATURE ON LARVAL SURVIVRI DEVEMPMENT

.

GROWTH AND CHROMOSOME PREPAIWXION

.

QUALITY

...

^{6 4}

INTRODUCTION

...

6 4 MATERIALSANDMETHODS

...

^{6 5}

...

s ~ r ~ i v a l a n d d a v a l a p e n t t i m e 6 5 G r o w t h

... ...

6 7 C h r o m ~ ~ o m ~ p r e p a r a t i o n q u a l i t y 6 8 D a t a a n a l y s i s

...

^{6 9}

RESULTS

...

⁷⁰

C y t ~ l ~ g i c a l i d e n t i f i c a t i o n s

...

^{7 0}

s u r v i v a l

...

^{7 1}

~ e v e l o p m e n t

...

⁷¹

G r o w t h

... ...

^{7 4}

C h r o m o s o m e q u a l i t y 7 5

D I S N S S I O N

...

^{7 6}

S m Y

...

^{8 5}

CHAPTER 5

.

NACRODISTRIBUTION PATTERNS OF LARVAE

.

^I

.

FACTORS ASSOCIATED WITH CYTOTYPEOCCURRENCE

...

^{9 7}

...

INTRODUCTION 9 7

...

MATERImSIINDHETHODS 9 8

...

S a m p l i n q p r o c e d u r e s

...

9 8 C y t o l o q i s a l i d e n t i t i o a t i o n o a t

.

a n a l y s i s

...

1 0 0 1 0 1

...

Cytotype f a u n a 104

A n a l y s i s o f s t r e a m v a r i a b l e s

...

¹⁰⁵

~ r e a u a n c v a n d c o r r e l a t i o n a n a l v s e s

...

¹⁰⁶

...

DISCUSSION 109 S r n Y

...

¹²²

CHAPTER 6. HIICRODISTRIBL2ION PATTERNS OF LARVAE

.

I 1

.

FACTORS ASSOCIATED WITH CYTOTYPE COMPOSITION AND ABUNDIWCE

...

¹⁴³

...

INTRODUCTION 143 MATERIALSANDMETHODS

...

¹⁴⁴

c y t o t y p e abundance w i t h i n a s i n g l e d r e i n a g a b a s i n

...

144

I n f l u e n c e of o u t l e t s on Eytotype composition

...

¹⁴⁵

Adult d i s p e r s a l

...

¹⁴⁷

Data a n a l y s i s

...

¹⁴⁸

C v t o t v ~ e abundance

...

¹⁴⁸

...

RESULTS 150 c y t o t y p e abundance w i t h i n a s i n g l e d r a i n a g e b a s i n

...

¹⁵⁰

I n f l u e n c e of o u t l e t s on s y t o t y p e composition

...

1 5 1 Adult d i s p e r s a l

...

¹⁵²

DISCUSSION

...

¹⁵³

CHAPTER 7

.

MICRODISTRIBUTION PATTERNS OF SUBLACUSTRINE CYMTYPES

...

¹⁷⁴

INTRODUCTION

...

¹⁷⁴

Study s i t a s

...

174

sampling prooedures

...

¹⁷⁶

C a l c u l a t i o n o f p r e f e r e n c e curves

...

¹⁷⁸

s i z e - v e l o o i t y and a i z e - d e p t h r e l a t i o n s h i p s

... ...

¹⁸²

Lsborataryvelocitystudies 182 a r t i f i c i a l streams

...

¹⁸²

Experiment 1

...

¹⁸⁴

Experiment 2

...

¹⁸⁵

Expeeinent 3

...

¹⁸⁵

v i i i

Analysi80idata

...

185

RESULTS

...

¹⁸⁶

Preference curves

...

¹⁸⁶

size-velocity and size-depth relationships

...

189

Laboratoryvelocitystudies

...

¹⁹⁰

DISCUSSION

...

¹⁹¹

SUHIW(Y

...

²⁰³

CHAPTW8.PHENOU)GY

...

²³¹

INTRODUCTION

...

²³¹

Study sitas

...

²³³

Sampling procedures

...

234

oat

.

analysis and evaluation of the sampling proqran

..

217

RESULTS

...

²³⁹

Evaluation or the aamplinq program

...

239

Cytotypa componitian among stations and substrates

....

240

seasonal succession of larval cytotypes

...

241

DISCUSSION

...

²¹³

Evaluationof the samplingproqrem

... _....

²⁴³

Cytotype composition amonq stations and substrates 215 Seasonal succession of larval cytotypes

...

216

S W Y

...

²⁵⁰

C H A P T W 9

.

ALWMETRY IN LAST LARVAL INSTARS OF EPOlC AND ACD

...

²⁸⁰

INTRODUCTION

...

280

MTERIALSANDNETHODS

...

²⁸¹

RESULTS

...

²⁸²

DISCUSSION

...

²⁸³

6-Y

...

²⁸⁵

CHAPTER 10

.

CONCLUDING DISCUSSION AND S W Y

...

²⁸⁷

CYTOSPECIES LIFE HISTORY - A SYNOPSIS

...

²⁹¹

EFGlC

...

²⁹¹

AC(qb) ysm~tum

...

²⁹²

CC2 x m . L % g n a n d CC3

...

293

A A yerecundurn

...

²⁹³

ACD Yerecundux

...

²⁹⁴

REFERENCES

...

300

APPENDICES

...

^+.325

APPENDIX I

.

Stream data and cytological identifiostions used in masrodistribution analysis (chapter 5)

...

³²⁵

APPENDIX 2

.

Table or computed confidence limits for percent

...

³³³

APPENDIX 3

.

Frouda number preference mixed ACD-AA and ACD cytotypes curves

...

for EFG/C

.

335 APPENDIX I

.

Weekly variation in larval abundance at 4 selnplinq stations for 1987 and 1988 (May to September)

...

³³⁸

APPENDIX 5

.

ninitab naoro used t o calculate the slope end 95% confidence linits for PA and FNA regression

...

³⁴⁵

LIST OF TABLES

TABLE 1.1. Stream factors associated with the maor'odistribution of larval and pupal

black flies

...

²⁴

TABLE 1.2. Stream factors associated with the microdistribution of larval and pupal black flies

...

27 TABLE 1.3. Cytologi~al descriptions of all presently

known Eytotypes in the Z ~ L L L U

m

-u! complex

...

²⁹

TABLE 2.1. Classification of stream bed particla. and riparian vegetation

...

^{4 5}

TABLE 3.1. Total number of individuals of each cytotype identified from the Avalon Peninsulr. from 1986-1989....

...

^{5 8}

TABLE 3.2. Summary of inversions identified on the 11s.

IIL and 1111 a m a of the EFGIC

oytotypa

...

⁵⁹

TABLE 3.3. summary of inversions identified on the IIL and IIIL ams of the CC2 and CC3

cytotypes

...

⁶⁰

TABLE 3.4. Sumnary of inversions identified on the IIS, IIL and IIIL arms of the Ac(gb)

vsnurrun

oytotype...

...

⁶¹

TABLE 3.5. Sumnary of inversions identified on the 11s.

IIL and IIIL arms of the AA yerecundun cytotype

...

⁶²

TABLE 3.6. Summary of inversions identified on the 11s.

and IIIL a m n of the ACD veracundyn

cytotype

...

⁶³

TABLE 4.1. Chi aquara and Tukey-type multiple oomparison analysis of EFG/C end ACD-AA larval survival at temperatures of 5

-

^30.C

...

86 T M L E 4.2. Kruskal-Wallis and Tukey-type multiple

cmparleon analysis of days and D o c requlred by EFG/C and ACD-AA to complete larval developnentac difrerenttezperatures

...

^{. . a 7}

TABLE 4 . 3 . Kruskal-Wallis and Tukey-type multiple comparison analyaie of l a r v a l development time (DDc and days) between EFG/C, ACO and AAatlSeC

...

88 TABLE 4 . 4 . Mann-whitney u t e s t s f o r sexual d i f f e r e n c e s

indevelopmenttime

...

83 TABLE 4 . 5 . WOVA and Tukey t e s t multiple -mparison

a n a l y s i s of EFGIC and ACD head capsule c h a ~ a c t e r s

...

⁹⁰

TABLE 4.6. Kruskal-Wallis and Tukey-type multiple coloparison a n a l y s i s of ACD l a r v a l chromosome neenaration a u a l i t v raared a t tenneeaturas

TABLE 4 . 7 . Degree-day requirements f o r soma North

...

American s i m u l i i d s 92

TABLE 5.1. Correlation c o e f f i c i e n t s used I,c o r r e l a t i o n a n a l y s i s between cytotype oocurrence and stream v a r i a b l e s

...

^{1 2 3}

TABLE 5.1. Total number of individuals o f each cytotype i d e n t i f i e d from 118 c o l l e o t i a n e on t h e Avalon Peninsula

...

^{1 2 4}

TABLE 5.3. ~ r u s k a l - w a l l i s and Tukey-type multiple comparison a n a l y s i s of cytotype riohness amon.. o u t l e t . t r i c k l e . ^..a11 and 1arae

-- - >, ~ - - - -

-.-

~ $ r e a m h a b i t a t s

...

¹²⁵

TABLE 5.4. WOVA and W e y m u l t i p l e :omparison analyeis of depth and pH among o u t l e t , t r i c k l e , small and l a r g e s t r e a m h a b i t a t s

...

¹²⁶

TABLE 5.5. Kmskal-Wallis and Tukey-type multiple comparison ~ n a l y s i s of stream v a r i a b l e s among o u t l e t , t r i c k l e , small and l a r g e stream h a b i t a t s

...

¹²⁷

TABLE 5.6. Range of continuous stream v a r i a b l e s under which each Eytotypewas found

...

¹²⁸

TABLE 5.7. Prequency a n a l y s i s (G-tests) of cytotype occurrence (+I-) among stream types

...

¹²⁹

TABLE 5.8. Correlation analysis between cytotypo o c c ~ r r e n c e and stream s i t e c o n d i t i o n s

...

130

TABLE 6.1. Estimated abundance (no.,s~re) of each SYtotYpe ~ 0 1 l e c t e d at each sampling a t a t x o n o n t ' l e P i c c o s d r a m a g e basin...

...

¹⁶¹

TABLE 6.2. Regression a n a l y s i s between l a r v a l abundance and s t r e a m e i t a c o n d i t i o n s for S. vennstuml veresundum l a r v a e and t h e CC2-3 and ActrrbI

~ y t ~ t y p e s . .

... ^.:1.'. ...

,152 TABLE 6.3. T o t a l number of i n d i v i d u a l s o f each c y t o t y p f

i d e n t i f i e d a t Axes Pond and Broad Cove Brooks

...

¹⁶³

TABLE 6.4. Regression a n a l y s i s between p e r c e n t c y t o t y p e

~ o m p o a i t i o n ( a r c s i n e ) o f m, CC, a n d EPGIC

...

and d i s t a n c e ( l o g ) from a n o u t l e t 164 TABLE 6.5. T e s t s o f Hardy-Wetnberg e q u i l i b r i u m for t h e

IIL-4 autosOmal polymorphism i n 2 AA

p o p u l a t i o n s .

...

¹⁶⁵

TABLE 7.1. T i l e c o l l e o t i o n s used f o r f i t t i n g p e e f e r e n o e CUrVBD

...

²⁰⁵

TABLE 7.2. M i ~ r ~ d i s t r i b u t i o n models f o r l a r v a l and pupal abundance ( l o g y

+

1 ) . Nata t h a t v

-

v e l o c i t y , d = d e p t h and m = d i s t a n c e . . .

...

^,206

TABLE 7.3. Kruskal-Wallis and hlkey-type m u l t i p l e o m p a r i s o n a n a l y s i s of s t r e a m v e l o c i t i e s a m o n g l a r v a l = o l l e c t i o n s

...

²⁰⁷

TABLE 7.4. ANOVA and Tukey n u l t i p l e comparison a n a l y s i s of s t r e a m d e p t h among l a r v a l c o l l e c t i o n s . .

....

^,208

TABLE 7.5. ANOVA o f t h e mean h o u r l y r e l e a s e r a t e of l a s t i n s t a r l a r v a e among 3 t r o u g h v e l o c i t i e s . . ,209 TABLE 7.6. Frequency a n a l y s i s ( G - t e s t s ) of t h e hourly

movenent of l e s t i n s t a r l a r v a l EPGlC a t 3 v e l o c i t i e e

...

210 TABLE 8.1. Comparieons of c a l c u l a t i o n s o f mean p e r c e n t

c o n f i d e n c e i n t e r m l o (%CI) a n d c o e f f i c i e n t s of v a r i a t i o n lCvI f o r s i m o l e and s t r a t i f i e d

TABLE 8.2. C o r r e l a t i o n a n a l y s i s between t h e s e a s o n a l l o g mean abundanse of i n d i v i d u a l c y t o t y p e s onrocks, v e g e t a t i o n and f i l a m e n t s

...

²⁵³

TABLE 8.3. T o t a l number of i n d i v i d u a l s of each cytatype

...

i d e n t i f i e d a t t h e 4 phenoloqy s i t e s 254 TABLE 8.4. Chi square a n a l y s i s of c y t o t y p e composition

among d i f f e r e n t s u b s t r a t e s foe t h e BcO c o l l e c t i o n s , 1988

...

²⁵⁵

TABLE 8.5. Comparisons of ACD-AA l a r v a l d e n s i t y an rock

...

and v e g e t a t i o n s u b s t r a t e s from BCO, 1988 256 TABLE 8.6. nean ( fSD) stream pH, o o n d v c t i v i t y and dissolved Oxygen c o n t e n t a t each sampling s t a t i o n f o r t h e 1987 and 1988 f i e l d seasons ( e a r l y May t o nid September)

...

²⁵⁷

TABLE 9.1. Slope and 95% oonfidance l i m i t s f o r p e i n s i p a l a x i s (PA) and reduced major a x i s ( w ) regre8bion l i n e s Of head c a p s u l e measurements for l a b o r a t o r y reared EFGlC (10

-

3O0C) and ACD (10

-

25-Cl and f i e l d c o l l e c t e d EFGli..

....

²⁸⁶

TABLE A.1. S i t e l o c a t i o n , stream conditions a t time of c o l l e c t i o n and r e s u l t s of c y t o l o g i c a l i d e n t i t i s a c i o n s for macradiritribucion c o l l c c r i o n a (chapter 5)

...

326 TABLE A.2. 9% Confidence l i m i t s for t h e e s t i m a t e d

p e r c e n t (p) o f cytotype i n a sample based OD a subsample s i z e of

21.. ...

^.334

TABLE A.3. Phenology f i l a m e n t o o l l e c t i a n s , L i t t l e P~CCOS, 1987

...

³³⁹

...

TABLE A.4. Phenology f i l a m e n t c o l l e c t i o n s , Big Picoos 340 TABLE A.5. Phenology f i l a m e n t c o l l e c t i o n s , Ares Pond

o u t l e t

...

³⁴¹

TABLE A.6. Phenology rock c o l l e c t i o n s , M e s Pond o u t l e t , 1988

...

³⁴²

TABLE A.7. Phenology f i l a m e n t c o l l e c t i o n s , Beaohy Cove o u t l e t

...

³⁴³

TABLE A.8. Phenology c o l l e o t i o n s , n a t u r a l s u b s t r a t a , B e a c h y c o v s o u t l e t , 1988

...

³⁴⁴

x i v LIST OF FIGURES

FIG. 1.1. Ty. cal appearance of a feu1,an s t a i n e d s i l n u l i i d s a l i v a - y g l a n d c e l l p o l y t e n e chromosome, showing t h e c h ~ r a s t e r i s t i c l i g h t ( r e p e a t DNA) and dark

(areae o f g e n e t i c a c t i v i t y ) bands

...

³⁴

FIG. 2 . 1 Head c a ~ s u l e measurements of l s e t i n s t a r l a r v a e u s e d to'ersmine s i s e - t e m p e r a t u r e s i z e - v e l o c i t y a n d s i z e - d e p t h r e l a t i o n s h i p s a n d ' t o d e t e c t s i m p l e a l l o m e t r y o f s i z e . .

...

^.16

FIG. 4.1. Mean number of days t o complete l a r v a l development far EFG/C and ACD-AA (yerecundum) a t t e m p e r a t u r e s o f 5

-

^30.c

...

⁹³

FIG. 4.2. Number o f d a y s t o complete l a r v a l development f o r m a l e and female l a r v a e of ( A ) ACD a t 15°C, (8) EFGlC a t 15.C. and (C) EPGjC a t 2a°C

...

95 FIG. 5.1. L o c a t i o n of ~ o l l e ~ t i o n s i t e s , Avalon P e n i n s u l a .

Newfoundland

...

¹³¹

FIG. 5.2. Frequency h i s t o g r a m of c y t o t y p e r i c h n e s s among s i t e s

...

¹³¹

FIG. 5.3. Combined p e r c e n t c y t o t y p e composition f o r each s t r e a m t y p e

...

115 FIG. 5.4, Dendrogram of 60 s t r e a m s i t e s based on c y t o t y p e

fauna

...

¹³⁷

FIG. 5.5. Dendrogran o f sa s t r e a m s i t e s b a s e d on s y t o t y p e fa...<a

...

¹³⁹

PIG. 5.6. D a n a o g r a m o f o y t o t y p e a s s o c i a t i o n based on

...

n ~ n b e r o f ~ ~ - ~ o ~ ~ r r e n c e s 141

FIG. 6.1. The P i c c o s d r a i n a g e b a s i n showing t h e l o c a t i o n ofeach sampling s t a t i o n

...

166 FIG. 6.2. Observed abundance ( l o g x t 1) i n t h e P i c c o s

d r a i n a g e b a s i s vs p r e d i c t e d abundance

...

( l o g x + 1 ) b y r e g r e s s i o n a n a l y s i s 168 FIG. 6.3. Dendrogram of 7 s t r e a m s i t e s b a s e d on c y t o t y p e

fauna

...

¹⁷⁰

FIG. 6.4. R e g r e s s i o n a n a l y s i s between c y t o t y p e

...

c o m p o s i t i o n a n d d i s t a n c e from a pond o u t l e t 172

XV FIG. 7.1. Ceramic tiles used as artificial substrate to

...

~ o l l e ~ t l a r v a e a n d p u p a e 211 FIG. 7.2. Artificial styeam syrten used to test the

response of final instar larvae to changes inwatervelocity

...

213 FIG. 7.3. Velocity-preference curves for larval EFG/c,

ACD-AAandACD

...

²¹⁵

FIG. 7.4. Dist~nce-preferen~e curves for larval EPGIC end ACD

...

²¹⁷

...

PIG. 7.5. Depth-preference curves for larval EFGIC. 219 FIG. 7.6. Distance-preference and depth-preference

curves for pupal EFGIC (oollection 2)

...

²²¹

FIG. 7.7. Distance-preference and velocity-preference

...

svrvee forpupal ACD (oollection 6) 223 FIG. 7.8. Distance-depth, depth-velocity and distance-

velocity preference surface plots for larval EFGIC (collection 3) and ACD (oollection 6)

...

²²⁵

PIG. 7.9. Valocity-size and depth-size scattar plots for larvalEFG/C (collection31

...

²²⁷

FIG. 7.10. Velocity-size and depth-size scatter plots for larval ACD (collection 6)

...

²²⁹

FIG. 8.1. me Xoqans Pond drainage basin showing

...

location of the BCO sampling stations 258 FIG. 8.2. Pilament artificial sampler (filament plus

orange metal anchor)

h-.... ...

²⁶⁰

FIG. 8.3. Peroent cytotyee composition at each of the 4 sampling stations for the 1987 and 1988

...

collections (early Ma:, to mid September). .262 FIG. 8.4. Weekly variation in stream conditions at the

Beachy Cove outlet (BCO) aanpling station for 1987and1988

...

²⁶⁴

FIG. 8.5. Weekly variation in strbrm conditions at tho Axes Pond outlet (APO) sampling station for 1987and1988

...

266

x v i FIG. 8.6. Weekly v a r i a t i o n i n stream c o n d i t i o n s a t t h e

Big Picoos (BP) sampling s t a t i o n f o r 1987 and 19P".

...

^,268

FIG. 8.7. Weekly v a r i a t i o n i n stream c o n d i t i o n s a t t h e L i t t l e P i c c o s (LP) s a n p l i n g s t a t i o n For 1987....270 FIG. 8.8. S e a s o n a l s u c c a s r i o n of l a s t i n s t a r l a r v a l

o y t o t y p e s a t t h e Beachy Cove o u t l e t (BCO) s a m ~ l i n g . . s t a t i o n d u r i n s t h e 1987 a n d 1988 f i e l d seasons....

... r... ...

²⁷²

FIG. 8.9. s e a s o n a l s u c c e s s i o n of l a s t i n e t a r l a r v a l cytcstypes at the axea Pond o u t l e t (APO) s a m ~ l i n a

- .

s t a t i o n d u r i n a t h e 1987 a n d 1988 f i e l d seasons..

...

^{, 2 7 1}

FIG. 8.10. S e a s o n a l succession of l a s t i n s t a r l a r v a l c y t o t y p e s a t t h e L i t t l e P i o c o s (A) and B i g P i c c o s IB a n d CI samnlina s t a t i o n s d u r i n o t h e

. . .

1987 and 1988 f i e l d reasons...

...

^,278

FIG. 10.1. E E ~ l o g i c a l p r o f i l e s bared on gross s p a t i a l ( s t r e a m t y p e ) a n d gross temporal (months) d i f f e r e n c e s . .

...

^,296

FIG. A.1. Froude number-preference c u r v e s f b r l a r v a l EFGjC, ACD-AA and ACD..

...

^.336

S o i e n c ~ is the art of estimating the error of our o p i n i o n .

CHAPTER 1

GENERAL INTRODOCTION

Analyses of l a r v a l s a l i v a r y g l a n d p o l y t e n e chromosomes show t h a t most s i m u l i i d morphospacies ( i . e . , s p e c i e s d e s i g n a t e d on e x t e r n a l morphology) are complexes o f b i o l o g i c a l l y d i s t i n c t , m o r p h o l o g i c a l l y s i m i l a r , r e p r o d u c t i v e l y i s o l a t e d s i b l i n g s p e c i e s , which are r e f e r r e d t o a s c y t o s p e c i e s o r c y t o t y p e e ( R o t h f s l s 1979, 1981a b, 1 9 8 7 ) . Adler (1987) s u g g e s t e d 1

-

2 s i b l i n g s p e c i e s e x i s t , on a v e r a g e , for every nominal s p e c i e s i n any g i v e n area. Because of t h e d i f € i c u l t y i n s e p a r a t i n g s i b l i n g s p e c i e s u s i n g c o n v e n t i o n a l morphological C h a r a c t e r s , b i o l o g i c a l s t u d i e s have lagged far behind t h e r a p i d d e s i g n a t i o n of t h e s e c y t a t y p e s and have been l a r g e l y d a s c r i p t i v e i n n a t u r e (Adler 1987). A few r i g o r o u s s t u d i e s ( e . 9 . . Adler and Kim 1984; Ciborowski and A d l e r 1990) have shown e c o l o g i c a l s e g r e g a t i o n among s i b l i n g s p e c i e s . L e s s t h a n 101 of t h e w a r l d 8 s morphospectes have bean i n v a s t i q a t e d c y t o l o g i c a l l y (Crosskey 1987) and t h e nacemslty P a r a c o m p l e t e r e - e v a l u a t i o n of b e h a v i o u r a l , p h y s i o l o g i c a l , taxonomic a n d e c o l o g i c a l d a t a i s e v i d e n t .

Althmugh a nvlnber oi c y t o t y p e s i n t h e Simuliun venustumj - , B ~ B C U I I ~ U I ~ complex have been d e s c r i b e d ( R o t h f e l s & al. 1978;

R o t h f e l s ussla; Adler 1 9 8 s ) , l i t t l e i s known a b o u t t h e l a r v a l e c o l o g y of i n d i v i d u a l c y t o t y p e s . In North America, Lake and

Burger ( 1 9 8 3 ) e x a n i n e d t h e phenology o f l a r v a l a i m u l i i d s a t l a k e o u t l e t s i n New H a w e h i r e , which i n c l u d e d 5 c y t o t y p e s of the S . venustur/vverecvddm complex. Gordon and Cupp (1980) attempted t o e x p l a i n t h e occurrence of l a r v a l A/C ( r e f e r r e d t o a s AA-AC verecundum), ACD verecundum a n d CC

xm&z&m

among 4 s i t e s i n New Yark S t a t e on l i m n o l o g i ~ a l grounds. Ciborowrki a n d A d l e r (1990) p r o v i d e d e v i d e n c e of h a b i t a t s e g r e g a t i o n among ACD yerecundum, cC3 yenu.tu. a n d a- AlC-CC v cundum (oombined AA, AlC and CC verecu&m), a s did Hunter ( 1 9 9 0 ) f o r EPG/C

w,

CC venustun, ACD v e r e c u n d m and A/C v e r e c u n d u n . A d l e r (1986) r e p o r t e d ACD verecundum was e c O l o g i c a l l y d i s t i n c t from yenusturn l i n e c y t o t y p e s i n A l b e r t a . me few r e m a i n i n g s t u d i e s c o n t a i n e d l i m i t e d e c o l o g i c a l i n f o r m a t i o n , c o n s i s t i n g p r i m a r i l y o f collection r e c o r d s ( R o t h f e l s kf

a.

1978; R o t h e e l s 1981a; S n y d e r 1982; Cupp and Gordon 1 9 8 3 ; P i s t r a n g and B u r g e r 1984; c o l b o 1985; A d l e r and Xi. 1986; C u r r i e and A d l e r 1 9 8 6 ) .

P r e s e n t e d h e r e a r e t h e r e s u l t s of a 4 year broad-based e c o l o g i c a l s t u d y of t h o s e c y t o t y p e s of t h e S. -1 Yerecundum complex found on t h e Avalon P e n i n s u l a of Newfoundland. Emphasis was p l a c e d on t h e s p a t i a l a n d temporal d i s t r i b u t i o n of l a r v a l c y t o t y p e s , t h o u g h a s p e c t s of p r e i m a g i n a l p h y s i o l o g y a n d morphology, as v e l l a s a d u l t o v i p o s i t i o n and d i s p e r s a l , were i n v e s t i g a t e d .

The purpose of t h e p r e s e n t s t u d y was t o d e s c r i b e c o m p a r a t i v e l y the l a r v a l e c o l o g y of t h o s e c y t o t y p e s of t h e 8 . venustum/verecundum complex found an t h e Avalon P e n i n s u l a of Newfoundland. The h y p o t h e s i s u s e d t o s t r u c t u r e t h i s p r o j e c t w a s as f o l l o w s :

H

,: L a r v a l c y t o t y p e s o f t h e 8 , v c n u ~ t u l n l v e r e c u n d u q complex d o n o t e x h i b i t e c o l o g i c a l p r o f i l e s d i s t i n c t from e a c h o t h e r .

HA: At l e a s t some l a r v a l c y t o t y p e s p o s s e s s e s d i s t i n c t e c o l o g i c a l p r o f i l e s .

E c o l o g i c a l p r o f i l e s were l a r g e l y drawn from s p a t i a l and t e m p o r a l d i s t r i b u t i m d a t a . C h a r a c t e r i z a t i o n of c y t o t y p e s on s p a t i a l and t e m p o r a l axes has 2 advantages: i ) such d a t a may b e u s e f u l i n d e t e r m i n i n g s p e c i e s s t a t u s i n cares where c y t o l o g i c a l e v i d e n c e i n u n c l e a r and; i i ) t h e a b i l i t y t o r e l i a b l y i d e n t i f y c y t a t y p e assemblages and p r e d i c t t h e i r o c c u r r e n c e an s p a t i a l ( s t r e a n t y p e ) or temporal ( s e a s o n a l i t y ) c r i t e r i a would g r e a t l y r e d u c e t h e dependence on c y t o t a x o n o m i c i d e n t i f i c a t i o n .

A s s t r e a m t e m p e r a t u r e p l a y s a profound r o l e i n t h e l i f e h i s t o r y of p r e i m a g i n a l s i n u l i i d s and is of p a r t i c u l a r r e l e v a n c e t o c y t o t y p e e c o l o g y ( a b o v e ) , a d e t a i l a d l a b o r a t o r y i n v e s t i g a t i o n of t e m p e r a t u r e w a s a l s o undertaken.

R e l i a n o e on c y t o t a x o n o m i c p r o c e d u r e s r e s u l t s from t h e c u r r e n t i n a b i l i t y t o d i s t i n g u i s h l a r v a e on c o n v e n t i o n a l

4 morphological c r i t e r i a ( e . g . , R o t h f e l s &

a.

1978; ~ d l e r 1986; A d l e r and Kim 1986). Crosskey (1987) concluded t h a t morphometric a n a l y s i s of e x i s t i n g c h a r a c t e r s , r a t h e r t h a n a s e a r c h f o r new ones. would p r o b a b l y be r e q u i r e d t o s e p a r a t e s i b l i n g s p e c i e s . As r e c e n t a t t e m p t s have met w i t h l i m i t e d s u c c e s s ( n d l e r 1983; Snyder and L i n t o n 1983), a p r e l i m i n a r y morphometric a n a l y s i s was conducted t o d e t e r m i n e how e n v i r o n m e n t a l c o n d i t i o n s ( t e m p e r a t u r e ) may i n f l u e n c e t h e taxonomic value a € morphological c h a r a c t e r s .

.,EVTEW OP RELEVANT LITERATURE

s i m u i i i d l i f e history

s l a c k f l i e s ( s i a u l i i d a e : D i p t s r a ) are holometabolous i n s e c t s w i t h 4 d i s t i n c t s t a g a s of development, e g g , l a r v a , pupa and a d u l t (Cupp and Gordon 1981; C u r r i e 1986). G e n e r a l t r e a t m e n t s o l s i a u l i i d b i o l o g y i n c l u d e Crosskey (1973, 1 9 9 0 ) , L e i r d (19811. Peterson ( 1 9 8 1 ) , a n d Xim and N e r r i t t (1987).

With rare e x c e p t i o n s (e.9.. Croerkey 1973; P e t e r s o n 1981;

L a d l e & al, l 9 8 5 ) , a l l p r e i m a q i n a l s t a g e s o f t h a l i f e c y c l e a r e r e s t r i c t e d t o l o t i c ( r u n n i n g w a t e r ) h a b i t a t s r a n g i n g from t e m p o r a r y t r i o k l e s t o l a r g e r i v e r s (Davias et

a.

1 9 6 2 ; S t o n e 1964; S t o n e and Snoddy 1969; Colbo end Wotton 1 9 8 1 ) . A d u l t s a r e u s u a l l y d i m o r p h i c , a e r i a l and t e r r e s t r i a l ( D a v i e s & al.

1962: S t o n e 1964; Cupp and Gordon 1983).

5 Temperatuea, oxygen and p h o t o p e r i o d d e t e r m i n e t h e o n s e t a n d l o r r a t e o f embryonic d e v e l o p m e n t ( E l s e n 1979; ~ l n h o r and Smith 1979; Colbo and Wotton 1981; S h i p p and W h i t f i e l d 1 9 8 7 ) . Upon h a t c h i n g , e a r l y i n s t a r r o f t e n move w i t h i n a r i f f l e from o v i p o s i t i o n s i t e s t o l o c a t i o n s more s u i t a b l e f o r l a r v a l development ( S t o n e a n d Snoddy 1969; Reisen 1977; c o l b a and M o o r h ~ u s e 1979; COlbo end Wotton 1981). L a r v a e a t t a c h to s u b s t r a t e s by a p o s t e r i o r c i r c l e t of hooks embedded i n a s m a l l 1,s.: o f s i l k r e c r a t e d Prom t h e s a l i v a r y g l a n d s ( J a a n b a s k 1976;

W a l l a c e a n d M e r r i t t 1980). D i s p e r s i o n over a s u b s t r a t e is e i t h e r "spaced", w i t h a w e l l d e f i n e d area s u r r o u n d i n g e a c h l a r v a , or "Clumped", with e a c h l a r v a occupying o n l y enough s u b s t r c t e to a t t a c h t h e s i l k pad (Colbo and Wotton 1181;

Eynann and F r i e n d 1 9 8 8 ) .

Most l a r v a e p o s s e s s h i g h l y m o d i f i e d l a b r a l f a n s u s e d t o p a s s i v e l y P i l t e r suspended p a r t i c l e s Prom s t r e a m w a t e r ( W a l l a c e a n d N e r e i t t 1980; C o l b o a n d Wotton 1981; C u r r i e a n d C r a i g 1 9 8 7 ) . Attached l a r v a e , w i t h t h e head i n e downstream d i r e c t i o n , t w i s t t h e body l o n g i t u d i n a l l y (90

-

^{180.1 t o use}

t h e v e n t r a l surface of aach h e a d f a n t o P i l t e r water ( W a l l a c e and M e r r i t t 1 9 8 0 ) . F a c u l t a t i v e s c r a p i n g , o b l i g a t o r y s c r a p i n g . d e p o s i t f e e d i n g and o p p o r t u n i s t i c p r e d a t i o n a r e a l t e r n a t i v e f e e d i n g s t r a t e g i e s (Chance 1 9 7 0 ; C a l b o and Wotton 1981; Walsh 1985; c u r r i e and C r a i g 1987). Larvae f i l t e r p a r t i c l e s between 0 . 0 9 1

-

^{3 5 0 pm} w i t h t h e m a j o r i t y of p a r t i c l e s i n g e s t e d l a s s t h a n l o o p n (Wotton 1976; Chance 1977; Wallace and M e r r i t t

6 1 9 8 0 ; W a l s h 1 9 8 5 ) . F e e d i n g e f f i c i e n c y i s low, g e n e r a l l y b e l o w 1 0 % ( K u r t e k 1 9 7 8 ) .

T h e l a r v a l d i e t c o n s i s t s of d e t r i t u s , b a c t e r i a , a n i n a l t i s s u e a n d a l g a e ( F r e d e e n 1964; Wallace e n d M e r r i t t 1980;

Wotton 1980a; Walrh 1985; S c h r e d e r 19871. Gut c o n t e n t s are l a r g e l y d e t e r m i n e d by p a r t i c l e s i z e a n d a v a i l a b i l i t y i n t h e s e s t o n (Anderson a n d Dicke 1960; Moore 1977a b; Kurtak 1978.

1979; S c h r a d e r 1983; Thompson 1987.3). The r i z a d i s t r i b u t i o n of i n g e s t e d p a r t i c l e s may s h i f t w i t h l a r v a l a g e (Schrijder 1981, 1 9 8 1 ; ~ h o m p s o n 1 9 8 7 a ) . Recent r e v i e w s r e l e v a n t t o l a r v a l f e e d i n g i n c l u d e Wallace a n d M e r r i t t ( 1 9 8 0 ) . Walsh (1985) and C u r t ' i e a n d C r a i g (19871.

T h e l a r v a l s t a g e can l a s t from 2 weeks t o s e v e r a l m o n t h s d e p e n d i n q on s t r e a m t e m p e r a t u r e , food a v a i l a b i l i t y and s p e c i e s (Lewis a n d B e n n e t t 1971; R o s s a n d M e r r i t t 1978, 1987: Merritt g d. 1978. 1982; c o l b o 1979, 1982; c o l b o and P o r t e r 1 9 7 9 , 1 9 8 1 ) . T h e number o f l a r v a l i n s t a r s v a r i e s between 6

-

11, d e p e n d i n g on s p e c i e s and s t r e a m c o n d i t i o n s (Ross and Merritt 1978; C o l b o a n d Wotton 1 9 8 1 ; c u r r i e 1986; c o l b o 1 9 8 9 ) . M a t u r e l a s t i n s t a r s ( i . e . , p h a r a t e p u p a e or p r e p u p a e ) w i l l o f t e n move t o c a l m e r w a t e r b e f o r e s p i n n i n g a cocoon o f s i l k i n w h i c h t o p u p a t e ( M a i t l a n d and Penny 1 9 6 7 ; C r o s s k e y 1973; c o l b o and Moorhouse 1 9 7 9 ) . P u p a l d e v e l o p m e n t v a r i e s from 2 days t o 2 weeks d e p e n d i n g o n t e m p e r a t u r e ( S t o n e 1961; Eleen 1979;

P e t e r s o n 1 9 8 1 ; deMoor 1982; P e U g e l 1 9 8 8 ) . A d u l t s e m e r g e d i u r n a l l y f r o m t h e p u p a l s k i n a n d r i s e t o t h e stream s u r f a c e

7 i n an a i r b u b b l e (crosskey 1971; P e t e r s o n 1981; Wenk 1981).

R e p r o d u c t i o n i s u s u a l l y s e x u a l , with c o p u l a t i o n a c c u r r i n q e i t h e r i n m a t i n g swarms or b y i n d i v i d u a l males w a i t i n g f o r females near s t r e a m s , h o s t s , o r n e c t a r s o u r c e s (Davies et

a.

1962; S t o n e 1964: Crosskey 1973; riank 1987). ripl lo id p a r t h e n o g e n e t i c forms a l s o occur ( R o t h f e l s 1979, 1 9 8 9 ) . A d u l t f e m a l e s u s u a l l y r e q u i r e a bloodmeal i n o r d e r t o develop e a c h b a t c h of e g g s (anautoganous), a l t h o u g h some s p e c i e s n a t u r e t h e f i r s t b a t c h w i t h o u t a blood meal ( a u t a g a n o u s ) w h i l e o t h e r s d o n o t t a k e b l o o d ( n a v i e s st

a.

1977; c v r r i e 1486; ~ n d e r s a n 1 9 8 7 ) . Most blood sucking s i m u l i i d s f e e d d i u r n a l l y on mammals (mammalophilic) or b i r d s ( o r n i t h o p h i l i c ) , though a t t a c k s on o t h e r v e r t e b r a t e s and i n v e r t e b r a t e h o s t s are known (Davies &

a.

1962; S t o n e 1961; Stone and Snoddy 1969; Croeskey 1973, 1990).

A d u l t s take p l a n t j u i c e s such as n e c t a r t o s a t i s f y e n e r g y r e q u i r e m e n t s ( P e t a r s o n 1981; C v r r i e 1986). Females c a n d i s p e r s e 200

-

600 km from b r e e d i n g sites i n s e a r c h o f s u i t a b l e h o a t e (Fredeen 1969; Walsh

&a.

1981), b u t 15 kn o r l a s s is p r o b a b l y t h e normal r a n g e of movement (Stone 1964;

Bennett a n d F a l l i s 1971; Wenk '981). Adult l o n g e v i t y is Usually less t h a n a month ( B e n n e t t and F a l l i s 1971; Crosskey 1973, 1990: asmnback 1976).

O v i p o s i t i o n u s u a l l y t a k a s p l a c e i n t n e evening, when females e i t h e r d e p o s i t eggs f r e e l y i n t o t h e stream o r a t t a c h e g g s i n masses to s u b s t r a t e s 1e.g.. r o c k s , t r a i l i n - a

8 vegetation, dam sluices) at or below thr! water line (Jamnback 1976; colbo and wotton 1981; Golini and Davies 1987). Other unique farms of oviposition have been recorded (Peterson 1981;

Ladle

&a.

1985). ~ o s t species deposit 100

-

600 eggs par gonatrophic cycle, although this can vary from 25 (Gvmno~&s stone) to 800 (sirnuliun Latreille) (Davies & d. 1962;

crosskey 1973, 1990; currie 1986). Depending on species or time of year, eggs can hatch .n several days or enter diapaube (Davies et al. 1962; Stone 1964; Jamnback 1976; Ross and Merritt 1987; Shipp 1987). Eggs cannot wilbstand desiccation (Imhof and smith 1'791, but same species may survive in the moist soil of dry stream beds for several n m t h s to several years (Fredeen ~3 ef. 1951; Anderscn and Dioke 1960; Colbo and Moorhouse 1974; Adler and Kim 1986). Recent reviews on sinuliid reproduction include Anderson (1987). Golini and navies (1987) and Wenk (1987).

The seasonal distribution of Nesrctis simuliids fall.

into 3 general categories (Stone 1964; Ross and Merritt 1987).

These include: i) univoltina rpecias (e.9.. PrDsinulium R01:baud) where eggs deposited in the spring or early summer hatch in late fall or early winter. Larval growth is slow over nost of the winter and pupation starts by early March; ii) univoltine species (e.9.. Simulium) where eggs deposited in the early summer hatch the fallowing spring. Larval growth is rapid and pupation starts by April or May and; iii) bivoltine and nultivoltine species (e.g., Sma.h) with eggs often

9 h a t c h i n g l a t e r t h a n g r o u p i l o r i i l

.

Larvae, pupae and a d u l t s may b e p r e s e n t a l l summer. Eggs l a i d by t h e l a s t summer or f a l l g e n e r a t i o n o v e r v i n t a r u n t i l t h e f o l l o w i n g s p r i n g .

S p a t i a l d i s t r i b u t i o a p a t t e r n s of p r e i n a q i n a l s i m u l i i a a S p a t i a l d i s t r i b u t i o n of p r e i m a g i n a l s i m u l i i d s h a s been c o n s i d e r e d o n 2 broad s c a l a r

-

r n a c r o d i s t e i b v t i o n ( i . e . , l a r v a l d i s t r i b u t i o n between s t r e a m and s e c t i o n s t h e r e o f ) and a i o r o d i s t r i b u t i o n ( i . e . , t h e d i s t r i b u t i o n o f l a r v a e w i t h i n a s m a l l s e c t i o n o f t h e s t r e a m ) ( c o l b o and ~ o t t o n 1 9 8 1 ) . s he b r o a d e s t m a c r o d i ~ t r i b u t i o n s t u d i e s have examined t h e d i s t r i b u t i o n of s i m u l i i d s among and w i t h i n t h e 6 zoogeographic r e g i o n s of t h e world (e.g., Crosskey 1981, 1 9 8 7 ) . Numerous s t u d i e s have c o n s i d e r e d p a t t e r n s of l a r v a l d i s t r i b u t i o n w i t h i n a l a r g e s e c t i o n o f a zoogeographic r e g i o n (e.9.. Cupp and Gordon 1983; Corkum a n d C u r r i e 1 9 8 7 ) . At t h e lowest s c a l e , s t u d i e s of m a c r o d i s t r i b u t i o n have examined l a r v a l d i s t r i b u t i o n between s t r e a m s i n h i g h l y l o c a l i z e d areas ( e . g . , Coibo 1979) and w i t h i n a s i n g l e d r a i n a g e b a s i n ( e . g . , M a i t l a n d and Penny 1967). These l a t t e r s t u d i e s have s t r e s s e d t h e r o l e of s t r e a m s i t e c h a r a c t e r i s t i c s ( e . g . , food s u p p l y . o v i p o s i t i o n a l cues, t e m p e r a t u r e , s u b s t r a t e ) i n d e t e r m i n i n g p r e i m a g i n a l d i s t r i b u t i o n .

D i s t e i b u t i o n w i t h i n a s t r e a m r e a c h ( e . g . , U l f s t r a n d 1967) o r d i s p e r s i o n over i n d i v i d u a l s u b s t i - a t e = ( e . 9 . . Rilhm and Page1 1986) has c u s t o m a r i l y been r e f e r r e d t o as n i c r o d i r t r i b u t i o n .

10 In recent years, laboratory studies have focused on the patterns of dispersion within groups and the factors responsible for these patterns (Craig and Chance 1982; Hart 1986; Chance and Craig 1986; Eymann and Friend 1288;

Ciborowski and Craig 1989).

Preimaginal habitat selection on any scale depends upon the interaction of numerous physical and biotic factors.

Tables 1.1 and 1.2 provide comprehensive (though not exhaustive) lists of those factors thought to influence preimaginal macrodistribution and microdistribution respeotively. Although some factors affect distribution over both scaler of study (e.9.. water velocity, substrate, biotic interactions), the influence of many factors can be ignored at the level of the nicrohabitat (Ulfstrand 1967; Rabeni and Minshall 1977). For example. water chemistry and temperature are unually oonsidered homogeneous over localized areas of a stream. Consequently, microdistribution studies have focused on conditions which vary over a distance of a few centimeteres o r meters, such as Water depth and velocity. Minahall and Minshall (1977) have suggested that microdistribution of benthic inseots is the product of a aeries of responses to a set of interacting variables imposed in a hierarchical fashion. These authors also emphasised that responses to stream conditions are species specific, hence the need to consider species individually.

Various factors may influence praisaginal distribution

11 via several pathways and different factors nay interact. Far exampla, velocity can influence larval microdistribution by its effects on filter feeding (Chance and Craig 1986; Craig and Galloway 1987; Morin and Peters 1988). substrate suitability (Ulfstrand 1967; deMarch 1976; Rabeni and Minshall 1977; Reice 1980; Minshall 19841, substrate stability (Newbury 19S4), and the distribution of potential predators and conpatitors (Ulfstrand 1967; ninrhall and Minrhall 1977; Orth and Maughan 1981)

.

Reviews concerned wholly or in part with the spatial distribution of preinaginalsilnuliids include Carlsoon (1967), Colbo and Wottan (1981), Orunewald (1981). Ross and nerritt (1987) and Wotton (1987).

Hydrodynamios or rlor

Hydrodynamic. are fundamental to larvalhabitatselection (Craig and Galloway 1987). General treatments on the consequences of flow to living organisms can be found in Voqel (1981, 1988). LUgt (1983). NoWell and Juaars (1984) and statzner nf s l . (1988). Specific treatments for silnuliids include Decamps

a.

(1975). Craig and Chance (1982). Chance and Craig (1986). craiq and el lo way (1987). Stream hydrology was reviewed by Newbury (1984).

velocity at t h e rubstrate-water interface is zero due to frictional forces, but increaser with distance from the substrate until mainstream velocity is reached (Statzner &

12

a.

1988). The r e g i o n where t h e w a t e r v e l o c i t y i s 901 (some a u t h o r s use 99%. see Chance and C r a i g 1986; s t a t r n e r & 43.

1988) or l a s s t h a n t h a t of t h e mainstream v e l o c i t y i s known as t h e boundary l a y e r ( c r a i g and Galloway 1 9 8 7 ) . I n s t r e a m s most of t h e boundary l a y e r i s t y p i c a l l y t u r b u l e n t , b u t f l o w immediately above t h e s u b s t r a t e e x h i b i t s l a m i n a r flaw and i n t e r r n e d t h e ' l a m i n a r T o r ' v i s c o u s s u b l a y e r ' ( C r a i g and Galloway 1987; S t a t z n e e &

a.

1988). It is i n t h e boundary l a y e r t h a t s i r n u l i i d l a r v a s are found ( C r a i g end Galloway 1 9 8 7 ) . Although it h a s o f t e n been assumed t h a t l o t i c i n s e c t s l i v i n g w i t h i n t h e boundary l a y e r are p r o t e c t e d from flow, r e c e n t s t u d i e s have Shawn t h a t l o t i c i n v e r t e b r a t e s n o g o t i a t e t h e complicated p a t t e r n s of flow and consequently d e a l w i t h t h e r e f o r c e s ( s t a t z n e r nf

a.

1988).

s i m p l e h y d r a u l i c c h a r a c t e r s , such a s d e p t h , v e l o c i t y and s t r e a m bottom s u b s t r a t e s , c o r r e l a t e w e l l w i t h b o t h t h e m a c r o d i s t r i b u t i o n end m i c r o d i s t r i b u t i o n of p r e i m a g i n a l s i m u l i i d s ( T a b l e s 1.1 and 1 . 2 ) . Assuming uniform flow, measurements of t h e s e v a r i a b l e s (mean v a l u e s ) a l l o w c a l c u l a t i o n s of complex h y d r a u l i c v a r i a b l e s ( S t a t z n e r

&a.

1988). These i n c l u d e Froude number, Reynolds number, v i s c o u s nublayer t h i a k n e s s , s h e a r s t r e s s , and boundary l a y e r Reynolds nunber. Froude and Reynolds numbers d e s c r i b e g e n e r a l f l o w c o n d i t i o n s ; v i s c o u s s u b l a y e r t h i c k n e s s , s h e a r stress, and boundary l a y e r Reynolds nunber d e s c r i b e c o n d i t i o n s near t h e stream bottom ( O r t h and Maughan 1983; Chance and C r a i g 1986;

13 Craig and Gallaway 1987; Statzner

s

al. 1988). Both ~ r o u d e number and viscoue sublayer thiokness are known to correlate with sinuliid distribution (statener 1981a; orth and ~ a u g h a n 1983; Wetmore t

a.

1990). At present it is not certain whether simple or complex hydraulic characters best describe the stream environment (Statzner t d. 198s).

Recently, Wetmore & 31. (1990) pointed out that under conditions of chaotic flow (e.9.. rapids) stream bed conditions such as shear stress and boundary layer thickness cannot be estimated using mean Plow velocity, depth, slope and substrate sire. Instead, a more detailed characterization of flow is required. Undoubtedly, tuture studies an stream ecology will place more emphasis on dccermining which hydraulic variables most influence insect distribution.

The hydrodynamics of flow at the substrate level also influence sinuliid dispersion patterns and biotic interactions (Craig and Chance 1982; Chance and Craig 1986; Craig and Galloway 1981; Ciboroweki and Craig 1989) which may in turn

~ n f l u e n c e distribution over higher scales.

Temperature

Temperature plays a major role in the ecology and evolution of aquatic insects (Ward and Stanford 1982; Sweeney 1984). stream temperature has a significant influanos on the macrodistribution (Table 1.1) and population dynamics (Ross and Merritt 1987) of preimaqinal simuliids as well as on:

14 embryonic development and eclosian (Elsen 1979; Imhof and Smith 1979; Shipp and Whitfield 19871, larval and pupal development ( ~ o k r y 1976; Elren 1979; colbo and Porter 1981;

demoor 1982; Merritt S EL. 1982; Prligel 1988; Wirte & &I,.

1990). larval survival (Davies and Smith 1958; Mokry 1976).

growth rate (Hauer and Benke 1987; Morin & EL. 1988a).

feeding (Schrlder 1981; Thompson 1987b), number of instars (Ross and Merritt 1978; Post 19831, larval size (ROSS and Merritt 1978; Merritt & al. 1982; deMoor 1982; Post 1983).

number of generations (zahar 1951; Carlsson 1962), emergence (Wenk 1981) end fecundity andlor adult sire (Chutter 1970;

Neveu 1973; Neveu and Lapchin 1979; Colbo and Porter 1981).

The seasonal abundance of preimaginal stages has also bean correlated with stream temperature (Mohsen and Mulla 1982;

shipp and Pracuniar 1986). Temperature may also act as a neans of partitioning species along a 'thermal gradient' (Merritt&

a.

1982).

The Simuliun v~nus&!glversoundw a. I . complex

The S . venustum/verecundum complex has a long and confused taxonomio history. A detailed account of this holarctic complex can be found in Rothfels & ga. (1978) and Gordon and Cupp (1980). This conplex is characterized by a larva With a negative head pattern and a pupa with 6 respiratory filaments.

S&4.L&m venustum was described by Say in 1821 from

15 adults collected by the Ohio River near Shippingsport (Rothfals S g l . 19781. Stone and Jamnback (1955) showed that S. venustua in North America was a complex of 2 morphoapecies.

the second, named verecundym, was distinguishable from 8.

m

Say an the basis of adult male genitalia. These authors also reported 8 . venustua a s univoltine and anthrophilis, whereas 8 . v e r e c w d u a Stone and Jamnbaak was multivoltine bnd did not attack man. navies & al. '19621 described diagnostic differences in the female genitalia.

Regional faunisticsueveys, ecological Investigationsand laboratory studies have produoed a great deal of information regarding t h e S . yenusrum/- 2. 1. complex (Stone and jamnback 1955; Wolfe and Peterson 1959; Anderson and Dicke 1960; Bennett 1960; Davian et al. 1962; Stone 1964; Abdelnur 1968; Craig 1969; Stone and Snoddy 1969; Chance 1970; Moore 1977a b; nerritt

&a.

1978; Bauer and Granett 1979; Bruder and Crana 1979; Inhof and smith 1979; Kurtak 1979; LeScala 1979; Wertwood and Brust 1981; Currie 1986; Shipp and Procunier 1986; Corkurn and Currie 1987; Marin S al. 1988bl.

This is particularly true in Newfoundland where all stages of the life cycle have been studied 1e.g.. Pickavance el g l . 1970; Davis 1971; Lewis and Bennett 1973, 1974. 1975; Ezenwe 1974; MOkry 1976; Colbo and Porter 1979, 1981; Colbo 1982;

~ c ~ r s a d i e

&a.

1984, 1985, 1986; Thompson 1987a b c ) .

~ r o m t h e above studies a general life history for the 5.

venurtum/verocundua complex can be constructed. I n North

16 America, larvae are found as far north as Alaska and as far south as Louisiana. In temperate regions the egg is the overwintering stage. Larvae are found in streams from ~ e b r u a r y to November, but are more commonly found between ~ p r i l and September. In mare southern locations (e.9.. Alabama) larvae nay he present throughout most o f the winter. Preimaginals have been found in almost every lotic habitat, from small temporary streams to large rivers. The pupal stage lasts approximately 1 week, depending an temperature.

Adults are dimorphic, anautogenous. mammalophilic blood feeders, which occasionally feed on birds. Due to their blood feeding habits, adults are one of the most important pasts of man and domestic livestock in NE North America. Females either deposit eggs freely into the stream where they sink to the bott~ln (ymu&m line ? ) or attach egg masses to substrates (a.9.. rocks, trailing vegetation) at or below the water line (verecundua line ? I .

Many studies have separated the larval S .

xswguu

complex from S. verecundum complex on morphological grounds.

However, recent studies have cast doubt on the ability of published morphological characters to separate larvae along these 2 lines (Rothfels

&a.

1978; Adler 1986; Adler and Kim 1986; Currie 1986; Calbo pees. coam. 1981). Therefore, all references to larval S . Yenustun or S. verecundun based on conventional morphological criteria should be considered S . venustue/verecundum p. 1. complex. Adults can usually be

17 separated into 5 . venusrun complex and S. w e c u n d u n complex (stone and Jamnback 1955; Davies al. 1962). In central Ontario, Hunter (1990) was able to assign adults and pupas of 4 cytotypes t o previously deasribed species: EFGIC venustum = S6mulium truncatua (Lundstrem) ; CC

venuscu. -

^{8 .}

^w;

^ACD

verec d u n =

r o -

(Lundsts8m); AlC verecundun=

5. yerecundun. Whether narpholoqical separation is possible over a larger geographic area remains to be Been.

Simuliid t a m n o m y

Simuliid systenatiss have changed considerably over the past 30 years as cytological and biochemical approaches have become increasingly more important in species recognition (Crosskey 19871. Based on traditional morphological characters, approximately 1500 species are currently recognized globally; to this can be added at least 150 cytotaxononicallyrecoqnized sibling species (Crosskey 1987).

Mast cytological studies of simuliids rely on salivary gland polytene chromosomes of late instars (Rothfels 1979;

Rothfels 1987), although adult polytene chromosomes.

especielly those from Malpighian tubule cells, are occasionally used (e.g., Bsda 1976; Adler 1983; Procunier and Post 1986; Hunter 1990). In many simuliid tissues, repeated chromosome replication within a single nucleus (endopolyploidyl, with replicates remaining tightly synapsed in parallel, results in very wide (Fig. 1.1) polytene

18

~ h r o r n ~ s o m e ~ (Farnsworth 1978). Simuliids almost invariably have 3 pairs (n = 3) of metacentric chromosomes (rarely n

-

^{2 1}

withhornologues intinatelypaired (~othfels 1979). Chromosomes are designated I, 11, and I11 in descending order of length, with short and long am. of each chromosome labelled s and L rerpeotivaly (Rothfels 1979).

stained polytene chrmosomes show very distinct light and dark banding patterns (Pig. 1.1), which allows visual detection of chromosomal rearrangements, such as inversions and interchanges (Rothfels 1979). Cytotypes commonly differ in fixed autosoma1 inversions, floating inversions (polymorphisms) or sex chromosomes. Other aspects of cytology, such as the presence/abeence of B chromosomes and details of mala meiosis can also vary among species (Rothfels & g l . 1978; Rothfels 1979, 198la b, 1987). Selection of which band sequence in a chromosona arm is considered standard or inverted is arbitrary, but by convention standard is selected for its 'centrality', i.e., the sequence which gives rise to the largest number of independent derivatives (Rothfels 1979).

Biochemical approaches t o simuliid taxonomy include gas liquid ohromatography of cuticle hydrocarbons (Cerlson and Walsh 1981; Phillips eta. 19851, enzyme electrophoresis (May

&

a.

1977; Snyder 1982; Snyder and Lintan 1983; Grams and zillmann 1984) and DNA sequencing (Tawnson &

a.

1987). To data most of these prosedures have met with limited sucsoss.

Reviews pertaining to simuliid taxonomy include morphological