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Pitcher plant, Sarracenia purpurea L., as an ecosystem Laird, Deborah Diemand 1969

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THIS PITCHER PLANT, Sarracenia purpurea L., AS AN ECOSYSTEM by DEBORAH DIEMAND LAIRD B.A., Smith College, 1966 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF Master of Science in the department of Zoology We accept this thesis as conforming to the require <L-«tandard The University of B r i t i s h Columbia August, 1969 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an a d v a n c e d d e g r e e a t the U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and S t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . It i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . The U n i v e r s i t y o f B r i t i s h C o l u m b i a V a n c o u v e r 8, Canada D e p a r t m e n t ABSTRACT The m i c r o e c o s y s t e m s i n t h e l e a v e s o f the p i t c h e r p l a n t , S a r r a c e n i a p u r p u r e a « were s t u d i e d o v e r a t h i r t y day p e r i o d . These p l a n t s were k e p t out o f d o o r s . One o f t h e s e p l a n t s was l a t e r b r o u g h t i n t o the l a b o r a t o r y and f o u r l e a v e s were s t u d i e d c o n c u r r e n t l y w i t h f o u r t u b e s . These s t u d i e s were i n t e n d e d t o show d i f f e r e n c e s , i f a n y , between l e a v e s s t u d i e d i n the f i e l d and t h o s e i n the l a b o r a t o r y , and between the l e a v e s and an a r t i f i c i a l e n v i r o n m e n t . Organ i sms i n a l l o f t h e s e v e s s e l s were c o u n t e d and t h e i r t o t a l b iomass and oxygen c o n s u m p t i o n g r a p h e d . T h r e e o f the l a r g e r o r g a n i s m s f o u n d were t y p i c a l o f t h i s s p e c i e s o f p i t c h e r p l a n t , one t h r o u g h i t s e n t i r e l i f e c y c l e and t h e o t h e r two f o r t h e i r l a r v a l s t a g e s . An i n t e r e s t i n g f i n d i n g was t h a t the a l g a , M i c r o t h a m n i o n , seems t o i n h i b i t the growth o f T e t r a h y m e n a , p r o b a b l y due t o some e x t r a m e t a b o l i t e . paramecium was a p p a r -e n t l y e x c l u d e d f r o m a l l l e a v e s i n t h e f i e l d . The l e a v e s o f t h e p i t c h e r p l a n t were f o u n d t o be i d e a l f o r t h e f i e l d and l a b o r a t o r y i n v e s t i g a t i o n o f e c o l o g i c a l f o r c e s due t o t h e i r n a t u r a l o c c u r r a n c e , s m a l l s i z e , and r a p i d t u r n o v e r o f o r g a n i s m s . i i i TABLE OF CONTENTS' PAGE INTRODUCTION 1 MATERIALS AND METHODS 3' Plants and Leaves 3 Sampling 4 Counting 4 Photography and Measurements 7 Identification of Organisms 7 Experiment using Leaves and Tubes 8 RESULTS 10 DISCUSSION 13 Graphs 13 Macro- and Microinhabitants of the pitcher plant 13 SUMMARY 27 LITERATURE CITED 81 i v LIST OF FIGURES PAGE Figure 1. Counting chamber 29 Figure 2. F test for random sampling 30 Figure 3. Graph showing the relationship between the dry weight and oxygen consumption for micro-organisms 31 Figure 4. Table showing the occurrance of the major organisms in the leaves. Figures 5 - 1 6 . Biomass curves for leaves in the f i e l d 34-45 Figures 17 - 20. Biomass curves for leaves observed in the laboratory 46-49 Figures 21 - 24. Biomass curves for tubes observed in the laboratory 50-53 Figures 25 - 36. Oxygen consumption curves for leaves observed i n the f i e l d 54-65 Figures 37 - 40. Oxygen consumption curves for leaves observed in the laboratory 66-69 Figures 41 - 44. Oxygen consumption curves for tubes observed in the laboratory 70-73 Figure 45. A pitcher plant. 74 Figure 46. Anoetus gibsoni 75 Figure 47. Deutonymph 75 Figure 48. Chironomid larvae 75 Figure 49. Mosquito larva 75 Figure 50. Copepod 75 Figure 51. Rotifer 75 Figure 52. Chilodonella 76 Figure 53. Tetrahymena 76 Figures 54 - 61. C i l i a t e s observed in the leaves 76 Figure 62. Polytomella 77 Figure 63. Peranema 77 Figures 64 - 75. Flagellates observed i n the leaves 77 Figure 76. Arcella shell 78 Figure 77. Amoeba radiosa 78 Figure 78. A. guttula 78 Figure 79. A^ s t r i a t a 78 Figure 80. Microthamnion 79 Figure 81. Diatom 79 PAGE Figure 82. 10^ rounds 80 Figure 83. Multinucleates 80 Figure 84. Yeasts 80 1 INTRODUCTION The study of ecology i s only possible through the investigation of small parts of complex systems or of simple systems, either naturally occurring or a r t i f i c i a l l y produced. The study of small parts of a large and complex system i s next to useless as an indicator of a l l interactions within the system as there are too many unknown forces at work on i t and too many other aspects not considered. An a r t i f i c i a l simple environment in a test tube or plastic cup or cage pan produce some worthwhile insights into ecological forces, but, being a r t i f i c i a l and more often than not carried out in the laboratory the interactions observed can not automatically be assumed to be the same as those in nature. A naturally occurring simple environment, either due to extreme con-ditions, as in the Antarctic or a sulfur spring, etc., or a very small, self-contained one, such as a pitcher plant leaf, seems; an ideal situation for a re l a t i v e l y extensive ecological study, as the effects of the environment, rain, wind, diurnal and seasonal temperature fluctuations, etc., can be observed as well as the effects of the organisms present. The pitcher plant was chosen for this investigation because i t can be studied in nature, as mentioned above, as well as in the laboratory, being more readily portable than some other small environments, such as tree bolls or moss lumps on granite faces. This brief study was intended as a survey to determine what potential the pitcher plant has the s o r t o f e x h a u s t i v e e c o l o g i c a l work m e n t i o n e d a b o v e . MATERIALS AND METHODS  Plants and leaves. The pitcher plants, Sarracenia purpurea» were collected from a sphagnum bog near Middlebury, Vermont, and planted in plastic wash basins in the sphagnum in which they were found. They were l e f t outside so that the environment would be as near to normal as possible. The plants were divided into three groups, a, b, and c, each group in a single basin, and under s l i g h t l y different conditions from the rest. Group a received r e l a t i v e l y l i t t l e strong sun, being on the north side of the house, and the most rain, as the infrequent thun-der storms which occurred during the study came from that direction. Group b received most strong sun and quite a b i t of dust, being on the east side of the house and facing a d i r t road. Group c received afternoon sun, probably l i t t l e dust, and least rain. A l l three had equal opportunity for capturing insects. Groups a and b were removed from the bog at the start of the study and c about two weeks previous to t h i s . Four leaves from each group were chosen for study (I - IV), varying in degree of development from young, just-opened, to old, presumably the previous year's growth. Im-mediately after opening the young leaves contained no water and were i n i t i a l l y f i l l e d with d i s t i l l e d water. Counts of the micro-fauna in the l i q u i d of each of the four leaves of one of the three groups were made daily for t h i r t y days, so that a particular leaf was counted every third day and there were ten counts in a l l for each leaf. 4 S a m p l i n g . Samples were t a k e n out o f the l e a v e s w i t h a 5 m l . s y r i n g e w i t h a b l u n t , w i d e - b o r e n e e d l e t o p r e v e n t i n j u r y t o the l e a f and i t s i n h a b i t a n t s . The c o n t e n t s o f the l e a f were t h o r o u g h l y mixed by pumping the s y r i n g e two o r t h r e e t i m e s . The s y r i n g e was r i n s e d between samples i n t ap water and t h e n d i s t i l l e d w a t e r . A f t e r the sample was t a k e n the l e a f was r e f i l l e d w i t h d i s t i l l e d water t o a l e v e l somewhat be low the l i p o f the l e a f . T h i s was done because i n s e c t s c o u l d e a s i l y e scape from the l e a f i f i t were f i l l e d a l l the way. Counts were made i n a 1 . 5 m l . chamber made by a t t a c h i n g a p l e x i g l a s r i n g t o a l a r g e c o v e r g l a s s w i t h V a s e l i n e (see F i g . 1 ) . C o u n t i n g . S l i g h t l y o v e r 1 . 5 m l . o f p i t c h e r l i q u i d was put i n t o the chamber and the sample examined on a L e i t z d i s s e c t i n g m i c r o -scope t o i d e n t i f y and count the l a r g e o rgan i sms such as m i t e s and f l y l a r v a e and t h e n on a N i k o n model H i n v e r t e d f i e l d m i c r o s c o p e t o f a c i l i t a t e the l a t e r i d e n t i f i c a t i o n o f the s m a l l e r o rgan i sms i n the k i l l e d p r e p a r a t i o n . A drop o f 1.5% osmium t e t r o x i d e i n w a t e r was a d d e d , the chamber s t i r r e d and a c o v e r s l i p o p u t o v e r the chamber t o squeeze out e x c e s s wa te r and t o e l i m i n a t e c u r r e n t s i n the chamber . I t was t h e n l e f t t o s e t t l e f o r about t e n minute s whereupon c o u n t s were made on a l l o rgan i sms l a r g e r t h a n b a c t e r i a . The s e t t l i n g t ime v a r i e d somewhat d e p e n d i n g on the d e n s i t y o f the o rgan i sms i n the chamber . The d e n s e r samples were l e f t l o n g e r than the s p a r s e o n e s . To d e t e r m i n e when the sample had s e t t l e d 5 s u f f i c i e n t l y f o r accurate counting, the microscope was focussed up and down and when the organisms appeared as nearly as possible i n a s i n g l e plane counting could begin. The l a r g e r organisms were counted f i r s t to give any of the smaller ones s t i l l suspended a chance to s e t t l e . In some cases i t was necessary to use a ,75ml. chamber, h a l f the height of the 1.5ml. one, as o c c a s i o n a l l y there was such heavy growth of b a c t e r i a and protozoa as to make the l i q u i d v i r t u a l l y opaque i n the large chamber. In extreme cases i t was necessary to d i l u t e the l i q u i d as much as 1:4 and more. This was done by adding 32 drops of d i s t i l l e d water to 8 drops of l i q u i d i n the large chamber and counting as usual. In these cases the large organisms such as mites and f l y larvae were counted i n the .75ml. chamber before t h i s f l u i d was used i n the d i l u t i o n s i n the 1.5ml. chamber where the small organisms were counted. Osmium tetroxide was used as a k i l l i n g s o l u t i o n as i t k i l l s the organisms very q u i c k l y and with a minimum of d i s -t o r t i o n . The mites and larvae were s u r p r i s i n g l y undisturbed by i t s a d d i t i o n which i s probably due to t h e i r l a r g e r bulk and therefore slower penetration of the poison to t h e i r v i t a l organs. I f l e f t f o r long enough they too perished. Counts were made by determining the number of a species i n several f i e l d s and f i n d i n g the average number i n a f i e l d . The number of f i e l d s counted var i e d according to the u n i f o r -mity of d i s t r i b u t i o n . Those species which occurred i n large numbers often occurred i n s i m i l a r q u a n t i t i e s from f i e l d to 6 f i e l d and therefore were counted i n rather few f i e l d s . However, the r a r e r species often d i f f e r e d widely i n numbers i n d i f f e r e n t f i e l d s and were counted i n a large number of f i e l d s . In order to check the r e l i a b i l i t y of the counts a te s t f o r randomness was performed on f i g u r e s obtained i n two counts of two species i n a l e a f and a tube (see F i g . 2). The number of organisms per ml. was l a t e r c a l c u l a t e d from the counts, using various conversion f a c t o r s depending on which chamber was used, how high the d i l u t i o n was, and what magnification was used f o r the count. F i r s t , the average numbers i n a f i e l d at 4X, 10X, or 40X were converted to the t o t a l i n the chamber using a f a c t o r obtained by determining the proportion of the f i e l d area of the area of the chamber bottom. Then a second f a c t o r , e i t h e r 1.33 or .66, was used to convert the numbers per chamber (,75ml. or 1.5ml.) to the numbers per ml. Any conversions necessary due to d i l u t i o n s were incorporated i n t o t h i s f a c t o r . From the f i g u r e s thus obtained, biomass per ml. and oxygen con-sumption per ml. were c a l c u l a t e d and graphed. The rate of oxygen consumption was determined f o r each of the species by e x t r a p o l a t i o n using the graph shown i n Figure 3 which i s based on one of Hargraves ( '69) who has found that the oxygen consumption to dry weight r e l a t i o n s h i p of Zeuthen ('53) holds equally true f o r microorganisms. Dry weight was taken to be .10 of the biomass. The graphs of biomass and oxygen consumption shown i n Figures 5 - 4 4 were made using the 1132 computer with p l o t t e r . Organisms which were ex-t r e m e l y r a r e were not counted, but t h e i r presence n o t e d and r e c o r d e d on the base l i n e o f the graphs under the ap-p r o p r i a t e day. Photography and measurements. Photographs were made u s i n g Kodak P l u s - X f i l m which i s f a i r l y f a s t and v e r y f i n e g r a i n e d . A L e i c a camera back was used w i t h a L e i t z a d a p t e r . Photographs were made of a stage micrometer w i t h 10p u n i t s a t t h r e e m a g n i f i c a t i o n s , 4X, 10X, and 40X. These photographs and those o f the organisms were e n l a r g e d t o the same e x t e n t so t h a t the photographed m i c r o -meter c o u l d be used d i r e c t l y as a r u l e r t o measure the organisms. Average dimensions were o b t a i n e d f o r each s p e c i e s , and average biomass o f a s i n g l e i n d i v i d u a l o f the s p e c i e s was c a l c u l a t e d . U s i n g these f i g u r e s and the number p e r ml. p r e v i o u s l y d e r i v e d , the t o t a l biomass p e r ml. was o b t a i n e d and graphed as mentioned above. I d e n t i f i c a t i o n of organisms. The m i t e s and deutonymphs were i d e n t i f i e d t o the s p e c i e s l e v e l from the paper o f Hunter and Hunter ('64) wherein t h e y a r e d e s c r i b e d . The mosquito and c h i r o n o m i d l a r v a e were i d e n t i f i e d as such and t h e i r f u r t h e r i d e n t i t y i n f e r r e d from papers by Dodge ('47) and P r i c e ('58) whose work suggests t h a t Wyeomia i s the o n l y genus o f mosquito which spends i t s l a r v a l stage i n the p i t c h e r p l a n t , and by Judd ('59) who found the l a r v a e o f Metriocnemus i n the p l a n t and i m p l i e s t h a t t h i s may be i t s normal h a b i t a t . Tetrahymena and C h i l o -monas were i d e n t i f i e d from Kudo ('54) and MacKinnon and 8 Hawes ('61), Polytomella« Peranema and the amoebae from Kudo ('54), Microthamnion from Prescott ('62) and Tiffany and Britton ('52) in conjunction with the kind assistance of Dr. J. Stein, and the copepods from Meglitsch ('61). The other organisms were not identified, either because of uncertainty as to their nature (yeasts, multinucleates, lOjj, rounds), occurrance in insignificant numbers or frequenc (diatom, dissheveled), heterogeneity of the group (f lagel- . la t e s ) , or unimportance of specific identity due to there being only one member of the group present ( r o t i f e r s ) . Experiment using leaves and tubes. A second experiment was carried out on leaves of a pitcher plant which was brought into the laboratory and four p l a s t i c tubes. Fluctuation of external conditions was minimal. The temperature of the laboratory remained v i r t u a l l y constant throughout the study and there was, of course, no r a i n f a l l or cloud cover. Air currents were few and small and the bulk of the insects in the v i c i n i t y were refugees from the genetics laboratory and therefore probably free of any contaminating organisms other than bacteria. Other variables, which also existed in the plants l e f t outdoors, were generated by or i n t r i n s i c in the micro-ecosystem i t s e l f and included NH^, CO^ and 0^ concentration, pH, condition of the leaf, etc. An old leaf was chosen which contained a f a i r amount of debris in the bottom. This leaf was f i l l e d with dis-t i l l e d water, st i r r e d as thoroughly as possible and l e f t to i t s own d e v i c e s f o r a few days i l l u m i n a t e d by i n c a n d e s c e n t lamps f o r 16 hours a day. Then f o u r o t h e r l e a v e s were chosen, t h r e e young and h e a l t h y ones w i t h no v i s i b l e c o n t e n t s and one s m a l l , s l i g h t l y o l d e r i n d i v i d u a l . A l l f o u r were washed t h r e e times w i t h d i s t i l l e d water. Four round-bottomed p o l y e t h y l e n e c e n t r i f u g e tubes 1" i n diameter and 4" deep were then pushed i n t o the sphagnum at v a r i o u s a n g l e s . A l l e i g h t v e s s e l s then r e c e i v e d a 1.5ml. a l i q u o t from the o l d l e a f and were f i l l e d almost f u l l w i t h d i s t i l l e d water. Counts were made u s i n g the .75ml. chamber and a Z e i s s u p r i g h t m i c r o s c o p e e v e r y o t h e r day f o r the f i r s t t e n days and s p o r a d i c a l l y t h e r e a f t e r . On the s i x t h day of c o u n t i n g , f l i e s c a p t u r e d i n the p i g b u i l d i n g o f the a g r i c u l t u r e department were added t o two of the l e a v e s (1 and 4) and two of the t u b e s . The f l y from one of these escaped, but but the tube i n which the f l y remained (tube 3) showed good growth of m i c r o f a u n a . C o u n t i n g c o n t i n u e d as u s u a l a f t e r the a d d i t i o n of the f l i e s . Biomass and oxygen consumption were c a l c u l a t e d as b e f o r e and graphed ( F i g s . 17 - 24 and 37 - 4 4 ) 0 10 RESULTS Biomass and oxygen consumption f o r s p e c i e s i n a l l l e a v e s and tubes s t u d i e d a r e shown g r a p h i c a l l y i n F i g u r e s 5 - 4 4 , each graph showing curves f o r the v a r i o u s s p e c i e s i n a l e a f or tube over i t s e n t i r e p e r i o d of st u d y . A c h a r t showing the o c c u r r a n c e o f v a r i o u s organisms i n the l e a v e s s t u d i e d o u t s i d e i s shown i n F i g u r e 4. I f a p a r t i c u l a r s p e c i e s o c c u r r e d a t a l l i n a l e a f a t any time throughout the stu d y , i t was r e c o r d e d as +. The o n l y organisms which appeared i n a l l l e a v e s were mi t e s and, of c o u r s e , f l a g e l l a t e s . Those which o c c u r r e d i n a l l but one l e a f i n c l u d e d f l y l a r v a e , r o t i f e r s and 10\± rounds. The f l y l a r v a e ( F i g . 48) were c h i r o n o m i d l a r v a e and, as mentioned, were p r e s e n t i n most of the l e a v e s . Mosquito l a r v a e ( F i g . 49) were o c c a s i o n a l l y observed as w e l l , though not as o f t e n . The mi t e s ( F i g . 46) were p r o b a b l y Anoetus  g i b s o n i which s p e c i e s i s t y p i c a l o f S a r r a c e n i a purpurea and w i l l be d i s c u s s e d l a t e r . The deutonymph stage o f t h i s organism ( F i g . 47) appeared i n a l l but one o f the l e a v e s but seldom i n l a r g e numbers. I t s appearance was s p o r a d i c i n most l e a v e s and i t was almost c o n s t a n t l y i n evidence i n o n l y one ( I c ) . A s p e c i e s o f H a r p a c t i c o i d copepod ( F i g . 50) appeared i n t h r e e l e a v e s , but c o n t r i b u t e d an ^ appreciable« biomass t o o n l y one ( I b ) . R o t i f e r s ( F i g . 51) were r e p r e s e n -t e d by o n l y one genus i n the p l a n t s grown o u t s i d e and were f r e q u e n t l y found i n l a r g e numbers. However, i n the p l a n t s and tubes s t u d i e d i n the l a b o r a t o r y s e v e r a l s p e c i e s of 11 r o t i f e r s were found. Among the p r o t o z o a Tetrahymena ( F i g . 53) was the most common c i l i a t e f ound and was v e r y o f t e n p r e s e n t i n e x t r e m e l y h i g h c o n c e n t r a t i o n . Only one o t h e r c i l i a t e was o b s e r v e d i n l a r g e numbers, but t h i s s p e c i e s , C h i l o d o n e l l a ( F i g . 52), was o n l y p r e s e n t i n t h r e e of the twelve o u t s i d e l e a v e s and none i n the l a b o r a t o r y . Another c i l i a t e , d e s i g n a t e d as " d i s s h e v e l e d " ( F i g . 59) appeared a few times i n low numbers, but was never a major s p e c i e s i n the l e a f . The o n l y f l a g e l l a t e a p p e a r i n g c o n s i s t e n t l y and i n h i g h numbers was the c o l o r l e s s P o l y t o m e l l a ( F i g . 6 2 ) . One o t h e r f l a g e l l a t e d i d appear i n c o u n t a b l e numbers i n one l e a f . T h i s was the e u g l e n o i d Peranema ( F i g . 63) whose f i r s t o c c u r r a n c e was on the second t o the l a s t count on the l e a f . I t had i n c r e a s e d a p p r e c i a b l y by the l a s t count, but whether or not i t c o n t r i v e d t o remain i n the l e a f i n s t r e n g t h f o r any extended l e n g t h o f time must remain f o r e v e r a mystery. Many d i f f e r e n t s p e c i e s o f s m a l l , pigmented f l a g e l -l a t e s were observed ( F i g s . 64 - 7 5 ) , but seldom i n l a r g e numbers and never c o n s i s t e n t l y over a l o n g p e r i o d o f time. O n l y one pigmented a l g a appeared r e g u l a r l y and i n s i g n i f i c a n t amounts. T h i s was M i c r o t h a m n i o n . ( F i g . 8 0 ). S e v e r a l s p e c i e s o f amoebae were o b s e r v e d , never i n v e r y h i g h c o n c e n t r a t i o n . Of t h e s e , t h e r e was one s h e l l e d , A r c e l l a ( F i g . 7 6 ) , which appeared i n f i v e l e a v e s , and t h r e e naked s p e c i e s , Amoeba  s t r i a t a , A. g u t t a t a , and A. r a d i o s a ( f i g s . 77 - 79), which a l s o appeared i n f i v e l e a v e s . Three o t h e r organisms appear i n s u f f i c i e n t q u a n t i t i e s t o m e r i t some d i s c u s s i o n , a l t h o u g h 12 a l l t h r e e a r e of d o u b t f u l i d e n t i t y . The f i r s t i s s h e r i c a l and 10n i n d i a m e t e r . I t i s unpigmented, n o n - m o t i l e , w i t h a p p a r e n t l y a f a i r l y r i g i d c e l l w a l l and was never observed d i v i d i n g . I t i s r e f e r r e d t o as 10u round ( F i g . 82). The second i s a k i d n e y - s h a p e d c r e a t u r e , a g a i n c o l o r l e s s and non-m o t i l e . I t was t e n t a t i v e l y i d e n t i f i e d as a y e a s t ( F i g . 84), but was never observed budding. The t h i r d i s a v e r y s m a l l r o d - l i k e organism, a p p a r e n t l y m u l t i n u c l e a t e d , a l t h o u g h the i n c l u s i o n s o b s erved may have been something e l s e a l t o g e t h e r such as o i l d r o p l e t s or s p o r e s . They may be a c t i n o m y c e t e s and are r e f e r r e d t o as m u l t i n u c l e a t e s ( F i g . 83). 13 DISCUSSION  Graphs. As can be seen from the graphs ( F i g s . 5 - 4 4 ) , con-v e r t i n g the biomass t o oxygen consumption a l t e r s the apparent s i g n i f i c a n c e of the v a r i o u s s p e c i e s p r e s e n t . Small organisms whose t o t a l biomass i s e q u a l t o t h a t of a l a r g e r s p e c i e s w i l l consume more oxygen than the l a r g e r ones over a l l . In g e n e r a l , however, the o r d e r of magnitude of the d i f f e r e n c e between the lowest s p e c i e s on the graph and the h i g h e s t i s much the same i n b o t h the biomass and oxygen consumption graphs f o r the same l e a f . Biomass was p l o t t e d f o r the v a r i o u s s p e c i e s r a t h e r than numbers as t h i s g i v e s a b e t t e r i d e a o f the r e l a t i v e s i g - :.. n i f i c a n c e of each s p e c i e s p r e s e n t i n terms of b u l k . P l o t t i n g the oxygen consumption demonstrates the r e l a t i v e s i g n i f i c a n c e of the organisms i n terms of t h e i r a c t i v i t y and t h e r e f o r e p r o b a b l y g i v e s a more r e a l i s t i c a p p r o x i m a t i o n of the t r u e e c o l o g i c a l s i g n i f i c a n c e of the v a r i o u s s p e c i e s . Macro- and m i c r o i n h a b i t a n t s of the p i t c h e r p l a n t . I t i s i n t e r e s t i n g t o note t h a t a l l t h r e e of the major l a r g e organisms p r e s e n t (mosquito l a r v a e , f l y l a r v a e and m i t e s ) a r e t y p i c a l of S a r r a c e n i a p u r purea , and, i n f a c t , the mite spends i t s e n t i r e l i f e t h e r e . I d e n t i f i c a t i o n s of a l l t h r e e are t e n t a t i v e , but h i g h l y p r o b a b l e . The mosquito, Wyeomia s m i t h i i , t y p i c a l l y spends i t s l a r v a l s tage i n the l e a v e s o f S. purpurea i n i t s n o r t h e r n range, which would i n c l u d e Vermont (Dodge ('47), P r i c e ('58)). 14 Another s p e c i e s , W. h a y n e i , i s found i n t h i s p l a n t i n i t s s o u t h e r n range. The l a r v a e were found i n o n l y f i v e of the l e a v e s and never throughout the e n t i r e p e r i o d of s tudy. I n F i g u r e 7 the biomass may be seen to f o l l o w a r a t h e r smooth c u r v e f o r the h a l f of the s t u d y i n which the l a r v a e o c c u r r e d . T h i s i s p r o b a b l y due t o the numbers observed i n the l e a f b e i n g r e p l a c e d by the h a t c h i n g of eggs which had been de-p o s i t e d i n the l e a f b e f o r e the p l a n t had been removed from the bog. T h i s i s a l s o l i k e l y f o r those observed s p o r a d i c a l l y o c c u r r i n g i n o t h e r l e a v e s . U n l i k e the mosquito l a r v a e which were never found i n the l e a f i n the second h a l f of the study, the f l y l a r v a e were observed throughout the e n t i r e p e r i o d of s t u d y . Whether t h i s i s due to slower development than t h a t i n the mosquito or whether the f l y t r a v e l s over a wider range or i s l e s s s p e c i f i c i n i t s developmental r e q u i r e m e n t s i s un-known. Judd ('59) mentions the presence of Metriocnemus (a c h i r o n o m i d f l y ) i n a p i t c h e r p l a n t l e a f , but i n g e n e r a l t h e r e seems t o be l e s s c e r t a i n t y t h a t t h i s organism i s f o u n d o n l y i n t h i s h a b i t a t . S a r c o p h a g i d l a r v a e have been n o t e d i n p i t c h e r p l a n t s as w e l l ( P h i l i p ('53),; Judd ('59)), but none were seen d u r i n g t h i s s t u d y . S i n c e b o t h of the above two organisms r e q u i r e an a d u l t from o u t s i d e the l e a f to d e p o s i t eggs b e f o r e l a r v a e w i l l be o b s e r v e d , i t i s not s u r p r i s i n g t h a t they were not found i n the l e a v e s s t u d i e d i n the l a b o r a t o r y . I t i s a l s o not s u r -p r i s i n g t h a t the m i t e , Anoetus g i b s o n i , which spends i t s e n t i r e l i f e c y c l e i n the p i t c h e r p l a n t , was found t h e r e i n 15 the l a b o r a t o r y s t u d y . T h i s was the o n l y s p e c i e s o f m i t e p r e s e n t and was r e -p o r t e d by H u n t e r and H u n t e r ( ' 64 ) as b e i n g f o u n d o n l y i n the p i t c h e r s o f S a r r a c e n i a p u r p u r e a . P a u l i a n ( ' 63 ) o b s e r v e d a n o t h e r a c a r i n e , C r e u t z e r i a t o b a i c a , i n the p i t c h e r s o f N e p e n t h a c e a e , w h i c h may be a d a p t e d f o r l i f e i n t h i s p l a n t as A . g i b s o n i i s f o r S a r r a c e n i a . Be t h a t as i t may, A . g i b s o n i has not been f o u n d i n any o t h e r s p e c i e s o f S a r r a c e n i a even when S. p u r p u r e a i s g r o w i n g i n the same l o c a l i t y as o t h e r s p e c i e s , and no o t h e r s p e c i e s o f m i t e has been r e -p o r t e d i n h a b i t i n g S. p u r p u r e a . In t h i s s t u d y s e v e r a l o t h e r t y p e s o f m i t e were f o u n d , but t h e s e o c c u r r e d v e r y r a r e l y and s p o r a d i c a l l y and were o f t e n dead when o b s e r v e d w h i c h sugge s t s t h a t t h e y f e l l i n t o the l e a f and were t h e r e as l u n c h r a t h e r t h a n t e n a n t . I n g e n e r a l , the A n o e t i d a e i s a c u r i o u s f a m i l y . A l l o f i t s members are t y p i c a l o f h a b i t a t s c o n t a i n i n g a c o p i o u s m i c r o f l o r a o f b a c t e r i a and f u n g i , and have mouthpar t s h i g h l y *• m o d i f i e d f o r f i l t e r f e e d i n g . The d i s t r i b u t i o n o f A . g i b s o n i f rom p l a n t t o p l a n t i s p r o b a b l y a c c o m p l i s h e d by the f l i e s o r m o s q u i t o s whose l a r v a e a r e so o f t e n f o u n d i n the l e a v e s , as m e n t i o n e d above . The a n o e t i d s are f r e q u e n t l y f o u n d i n a s s o c i a t i o n w i t h l a r g e r a r t h r o p o d s i n t h e i r h a b i t a t and t h e s e a r t h r o p o d s no t i n f r e q u e n t l y s e r v e as t r a n s p o r t a t i o n f o r the hypopus o r deutonymph s tage o f the m i t e (Hughes ( ' 5 9 ) ) . The A n o e t i d a e v e r y o f t e n produce a deutonymph s tage i n t h e i r deve lopment w h i c h b e a r s no re semblance whatever t o the a d u l t . 16 S e v e r a l o f these deutonymphs were observed and r e c o r d e d on the graphs s e p a r a t e l y from the a d u l t s . There seem t o be no p a r t i c u l a r c o n d i t i o n s r e q u i s i t e f o r t h e i r appearance as they were seen i n l e a v e s w i t h c l e a r f l u i d as w e l l as c l o u d y and e x t r e m e l y c l o u d y . In l e a f IVb, which was a young, newly-opened l e a f , one of these nymphs was observed the f i r s t day the l e a f was counted. No o t h e r s e v e r a g a i n appeared i n the l e a f but from the second day of c o u n t i n g u n t i l the end of the s t u d y , m i t e s were p r e s e n t . As f o r the s m a l l e r organisms i n the p l a n t , the r o t i f e r s , p r o t o z o a , a l g a e and f u n g i , f a r fewer s t u d i e s have been made on them. Many may, i n d e e d , be as s p e c i f i c t o t h i s h a b i t a t as the l a r g e r c r e a t u r e s d i s c u s s e d above. I t seems u n l i k e l y i n the l i g h t o f the above-mentioned a d a p t a t i o n o f s e v e r a l l a r g e organisms t o l i f e i n the p i t c h e r p l a n t t h a t a l l the s m a l l e r i n d i g e n s o f the l e a v e s are merely a c c i d e n t a l im-mi g r a n t s from a n o t h e r h a b i t a t . More e x t e n s i v e s t u d i e s , i n -c l u d i n g c u l t u r e s i n the l a b o r a t o r y as w e l l as thorough f i e l d i n v e s t i g a t i o n s might prove r e w a r d i n g i n the c l a r i f i c a t i o n o f t h i s m a t t e r . A p p a r e n t l y the o n l y study which has been made s p e c i f i c a l l y on the p r o t o z o a of S a r r a c e n i a was made by Hegner ('26) who was t r y i n g to use p r o t o z o a as i n d i c a t o r s o f the nat u r e of the compounds p r e s e n t i n the p i t c h e r l i q u i d such as p r o t e a s e s . He examined the c o n t e n t s of t e n S. purpurea l e a v e s and r e -p o r t e d i n g e n e r a l what was t h e r e , but made no attempt at s p e c i f i c i d e n t i f i c a t i o n . Furthermore no e f f o r t was made t o 17 i n v e s t i g a t e the i n t e r r e l a t i o n s of the organisms found i n the l e a v e s o r i n o c u l a t e d i n t o the l e a v e s beyond n o t i c i n g whether or not the i n o c u l a t e d s p e c i e s s u r v i v e d . L l o y d ('42), i n h i s c l a s s i c work on c a r n i v o r o u s p l a n t s does not even mention p r o t o z o a i n c o n j u n c t i o n w i t h S a r r a c e n i a , beyond n o t i n g t h a t an i n v e s t i g a t i o n on the s u b j e c t might prove i n t e r e s t i n g . Both o f these a u t h o r s , however, d i s c u s s the i n t e r -r e l a t i o n s of p r o t o z o a and the u t r i c l e s o f the B l a d d e r w o r t , U t r i c u l a r i a , which a p p a r e n t l y uses Paramecium as a f o o d s o u r c e . Sorenson and J a c k s o n ('68) l a t e r c o n f i r m e d t h i s . Hegner's s t u d i e s on c u l t u r e s of p r o t o z o a i n o c u l a t e d i n t o S a r r a c e n i a p i t c h e r s i n the l a b o r a t o r y and out of d oors, open and unopen, i n d i c a t e t h a t a l t h o u g h Paramecium may not be d i g e s t e d by the p i t c h e r p l a n t , i t does not t h r i v e e i t h e r , a l t h o u g h i n s e v e r a l c a s e s Colpoda and Chilomonas were seen to m u l t i p l y . I t appears t h a t i n g e n e r a l p r o t o z o a are more l i k e l y t o s u r v i v e i n a p i t c h e r than i n a b l a d d e r of U t r i c u -l a r i a p o s s i b l y due t o d i f f e r e n t enzyme systems i n these two, which i s not s u r p r i s i n g s i n c e U t r i c u l a r i a i s d e s i g n e d t o t r a p s m a l l organisms w h i l e S a r r a c e n i a i s adapted t o handle l a r g e ones. D i g e s t i o n i n U t r i c u l a r i a p r o b a b l y depends f o r the most p a r t upon enzymes s e c r e t e d l a r g e l y by the p l a n t i t s e l f and v e r y l i t t l e on b a c t e r i a . On the o t h e r hand S a r r a c e n i a seems to depend a g r e a t d e a l on enzymes of bac-t e r i a l o r i g i n . I n e f f e c t the l e a f behaves l i k e a bug i n -f u s i o n where compounds r e l e a s e d by decay of the t r a p p e d 18 organisms are absorbed by the l e a f . Hepburn ('20 and '27) r e p o r t s s i g n i f i c a n t p r o t e a s e a c t i v i t y i n the s e c r e t i o n s o f the p i t c h e r p l a n t , but a p r e l i m i n a r y experiment done by the w r i t e r i n d i c a t e s t h a t the enzymes i n the l e a v e s are produced t o a l a r g e e x t e n t by two or t h r e e s p e c i e s of b a c t e r i a which a r e common i n them. The c u r i o u s f a c t which emerges from the s t u d i e s by Hegner on U t r i c u l a r i a and S a r r a c e n i a as w e l l as from t h i s i n v e s t i g a t i o n i s t h a t Paramecium i s , i f not a c t i v e l y e x c l u d e d from th e s e c a r n i v o r o u s p l a n t s , a t l e a s t somewhat i n h i b i t e d by them. In the s t u d i e s on U t r i c u l a r i a by Hegner i t was no t e d t h a t Paramecium was r e a d i l y k i l l e d and d i g e s t e d by the b l a d d e r . Other s p e c i e s o f p r o t o z o a were i n t r o d u c e d , i n c l u d i n g E u g l e n a , Heteronema, Phacus, C e n t r o p y x i s , C o l p i d i u m , S t e n t o r and S t y l o n y c h i a . A l l of these except f o r the l a s t t h r e e were u n i n j u r e d by the b l a d d e r , and these t h r e e remained a l i v e i n the b l a d d e r from s e v e r a l t o twenty hours a f t e r c a p t u r e , whereas Paramecium d i e d w i t h i n about 75 minutes a f t e r c a p t u r e . I n t h i s e x a m i n a t i o n o f t h e p i t c h e r p l a n t , which no doubt had ample i n t r o d u c t i o n s o f Paramecium s i n c e t h i s i s such a common genus i n almost any s t a n d i n g water, no Paramecium was ob-s e r v e d a l t h o u g h c o n d i t i o n s were t h e o r e t i c a l l y e x c e l l e n t f o r t h e i r growth. In the st u d y o f K r i s h n a m o o r t h i and B i c k ('66) on the growth and s u c c e s s i o n of c i l i a t e s i n peptone b r o t h , Paramecium appears i n l a r g e numbers a t the same time as Tetrahymena, Glaucoma t C o l p i d i u m and C h i l o d o n e l l a , a l l o f which were observed i n the p i t c h e r p l a n t , two i n v e r y h i g h c o n c e n t r a t i o n s . Why Paramecium s h o u l d a p p a r e n t l y be s e l e c t i v e l y e x c l u d e d , e i t h e r by d i g e s t i o n o r o t h e r forms of s u p p r e s s i o n i n both of the s e c a r n i v o r o u s p l a n t s i s a problem, e s p e c i a l l y i n the l i g h t of Maguire's ('63) f i n d i n g t h a t Paramecium s p e c i e s c o u l d e l i m i n a t e c e r t a i n o t h e r c i l i a t e s ( e . g . Colpoda) from i t s environment. I f t h i s i s t r u e , then the e x c l u s i o n o f Paramecium from the p l a n t s must have something t o do w i t h the p l a n t s themselves. Be t h a t as i t may, the c i l i a t e . - j which are found i n the l e a v e s a re f o r the most p a r t t y p i c a l o f the i n t e r m e d i a t e and f i n a l s t a g e s of the peptone s u c c e s s i o n of K r i s h n a m o o r t h i and B i c k . I n t h e i r s t u d y Tetrahymena p y r i f o r m i s developed e x t r e m e l y dense p o p u l a t i o n s i n media c o n t a i n i n g peptone and u s i n g b a c t e r i a as a f o o d s o u r c e , the c o n c e n t r a t i o n o f T e t r a -hymena b e i n g , b r o a d l y , d i r e c t l y p r o p o r t i o n a l t o the concen-t r a t i o n o f ibjer^entpne. i n the medium u n t i l a p l a t e a u i s rea c h e d where f u r t h e r a d d i t i o n s o f peptone have no e f f e c t due t o i n h i b i t o r y c o n c e n t r a t i o n s o f NH 4, C 0 2 , shortage o f 0^ or o t h e r f a c t o r s . At any r a t e , the g i s t i s t h a t Tetrahymena i s a b l e t o t o l e r a t e extremes of the af o r e - m e n t i o n e d f a c t o r s which would prove t o x i c t o many o t h e r s p e c i e s . T h i s s i t u a t i o n p r o b a b l y b r o a d l y p a r a l l e l s t h a t i n the p i t c h e r p l a n t l e a v e s , as the breakdown of the i n s e c t s t r a p p e d i n them would r e s u l t i n the c r e a t i o n o f a v e r y r i c h medium and c o n d i t i o n s s i m i l a r t o those observed i n the peptone b r o t h . Measurements of pH, Op, COp, e t c . were not made on the l e a v e s s t u d i e d , but 20 c o n d i t i o n s c o u l d be deduced i n g e n e r a l from the g e n e r a l appearance of the p i t c h e r l i q u i d c o r r e l a t e d w i t h the s t u d i e s o f K r i s h n a m o o r t h i and B i c k . That i s , l e a v e s c o n t a i n i n g opaque, r o t - s m e l l i n g , b a c t e r i a - i n f e s t e d f l u i d were assumed t o c o n t a i n h i g h c o n c e n t r a t i o n s of n u t r i e n t s u b s t a n c e s , NH^, C0 2 and low 0 2, w h i l e those w i t h c l e a r l i q u i d and few i n -h a b i t a n t s were assumed t o have a lower n u t r i e n t c o n c e n t r a t i o n and r e v e r s e c o n d i t i o n s o f the above. The degree of c l o u d i n e s s i s i n g e n e r a l r e f l e c t e d by the h e i g h t on the graph of the zone o f c u r v e s . Tetrahymena was common i n the peptone experiment o f K r i s h n a m o o r t h i and B i c k a l l through the study, though most numerous i n the i n i t i a l s t a g e s . Other h o l o t r i c h s were common as w e l l , as the y were i n the p i t c h e r p l a n t l e a v e s , but i n the l e a v e s o n l y Tetrahymena o c c u r r e d i n e x t r e m e l y l a r g e numbers c o n s i s t e n t l y . P o s s i b l y some f a c t o r : wascat work t o suppress these o t h e r c i l i a t e s which d i d not e f f e c t Tetrahymena» perhaps the same one which e l i m i n a t e d Paramecium. T h i s c o u l d e x p l a i n the v e r y h i g h numbers of Tetrahymena. With a l l a p p r e c i a b l e c o m p e t i t i o n gone and an u n l i m i t e d f o o d s u p p l y t h e r e would be n o t h i n g t o stop t h e i r growth but the d e v e l o p -ment of a p r o h i b i t i v e l y h i g h NH^ l e v e l . T h i s , of c o u r s e , i s sheer h y p o t h e s i s and f u r t h e r work would be n e c e s s a r y t o determine the t r u e f o r c e s a t work h e r e . Another s p e c i e s which f i g u r e d p r o m i n e n t l y i n the peptone s t u d i e s was C h i l o -d o n e l l a which t y p i c a l l y appeared i n the l a t e r s t a g e s o f the s u c c e s s i o n . T h i s i s a l s o t r u e i n the p i t c h e r p l a n t l e a v e s . 2 1 In most i n s t a n c e s where i t o c c u r r e d i t was i n the l a t e r p a r t o f the study, a l t h o u g h i n one l e a f (IVa) i t was observed i n l a r g e numbers b e f o r e the appearance of Tetrahymena. Tetrahymena, when p r e s e n t i n the l e a v e s , almost i n -v a r i a b l y m u l t i p l i e d r a p i d l y a f t e r i n t r o d u c t i o n and became by f a r the most preponderant organism o f the l o t , both i n biomass and oxygen consumption. T h i s i s t r u e i n s i x of the seven l e a v e s i n which t h i s organism was found ( I a , IVa, IVb, I c , l i e , I V c ) . In the seventh l e a f ( I I I c ) i t was observed on o n l y one day i n medium c o n c e n t r a t i o n and was not seen a g a i n e i t h e r b e f o r e or a f t e r t h i s time. E x a m i n a t i o n of the graphs p r o v i d e s c i r c u m s t a n t i a l e v i d e n c e t h a t the a l g a , M i c r o -thamnion, and Tetrahymena are m u t u a l l y e x c l u s i v e . Of the seven l e a v e s c o n t a i n i n g Tetrahymena, Microthamnion appears i n t h r e e . In IVa i t appears once, i n i n s i g n i f i c a n t c o n c e n t r a t i o n , s i x days b e f o r e Tetrahymena was f i r s t o b s e rved. I t i s un-l i k e l y i n t h i s case t h a t i t c o u l d e x e r t any a p p r e c i a b l e e f f e c t on Tetrahymena. In l i e i t i s p r e s e n t i n v e r y low c o n c e n t r a t i o n a t the same time t h a t Tetrahymena o c c u r s i n e x t r e m e l y h i g h c o n c e n t r a t i o n . Then the l a t t e r g r a d u a l l y appears i n lower and lower numbers and e v e n t u a l l y d i s a p p e a r s a t the same time t h a t Microthamnion i n c r e a s e s i n numbers and becomes one o f the major s p e c i e s i n the l e a f . I l l c i i s the l a s t l e a f i n which Microthamnion and Tetrahymena both o c c u r . I t i s a l s o the one i n which Tetrahymena never a t t a i n s v e r y h i g h c o n c e n t r a t i o n . I t s s o l e appearance o c c u r s t h r e e days a f t e r Microthamnion's f i r s t o c c u r r a n c e i n s i g n i f i c a n t con-22 c e n t r a t i o n . No counts were made between these two days so the i n c r e a s e and decrease i n the two s p e c i e s i s unknown. However, p o s s i b l y a l a r g e number o f Tetrahymena had a l r e a d y developed b e f o r e a s u f f i c i e n t c o n c e n t r a t i o n of M i c r o t h a m n i o n 1 e x t r a m e t a b o l i t e had accumulated and at the time of the count the numbers of Tetrahymena were a l r e a d y d w i n d l i n g . I t i s tempting t o assume t h a t the a l g a produces some i n h i b i t o r y e x t r a c e l l u l a r p r o d u c t which p r e v e n t s growth of Tetrahymena. An o b s e r v a t i o n i n support o f t h i s i s t h a t i n a l l of the above t h r e e cases of the two b e i n g found i n one l e a f , Microthamnion grows v i g o r o u s l y a f t e r Tetrahymena has grown i n s i g n i f i c a n t q u a n t i t i e s i n the l e a f , but the r e v e r s e was n ever seen. Very l i t t l e work has been done on Microthamnion so the n a t u r e of any i n h i b i t o r y e x t r a m e t a b o l i t e and the types of organisms e f f e c t e d by i t are unknown. There i s one o t h e r case of apparent i n d i r e c t i n t e r -dependence, a Y e a s t s ^ a r e f o u n d c o n l y i i n J l e a v e s : l b } v l l b ^ r a n d j,t io I l l b , , : T h i s i s a l s o t r u e of the copepods (see F i g . 4 ) . The q u e s t i o n a r i s e s as to whether t h i s i s because the copepod depends s o l e l y upon the y e a s t s as a f o o d s o u r c e , or the o c c u r r a n c e of the two t o g e t h e r a t a l l times b e i n g sheer c o i n c i d e n c e or the dependence of b o t h on some substance which i s p r e s e n t o n l y i n the t h r e e l e a v e s i n which these two o c c u r r e d . I t seems u n l i k e l y t h a t e i t h e r s h o u l d be dependent on some substance produced by the o t h e r . A l l t h r e e o f these l e a v e s were i n the same l o c a t i o n , and t h e s e two organisms may w e l l have been i n t r o d u c e d t o g e t h e r from the same s o u r c e , 23 p o s s i b l y d u s t . The two are never t o g e t h e r f o r a l o n g time i n l a r g e numbers. In l e a f l b both are p r e s e n t i n moderately h i g h numbers f o r two c o u n t s , but a f t e r t h i s the copepods i n c r e a s e i n numbers and the y e a s t s d i s a p p e a r . In the o t h e r two l e a v e s , l i b and I l l b , the yeastis are p r e s e n t throughout the s t u d y i n l a r g e numbers w h i l e the copepods appear s p o r a d i -c a l l y , i n f r e q u e n t l y and i n low numbers, so a l t h o u g h the e v i d e n c e s u p p l i e d by F i g u r e 4 suggests t h a t a p o s i t i v e c o r r e l a t i o n e x i s t s between the y e a s t s and copepods, examina-t i o n of F i g u r e s 8 - 1 0 i m p l i e s the r e v e r s e . I t i s noteworthy t h a t i n no case was t h e r e c o n v i n c i n g e v i d e n c e of a p r e d a t o r - p r e y r e l a t i o n s h i p between any two o f the s p e c i e s observed. T h i s suggests t h a t a l l of these organisms were dependent, e i t h e r d i r e c t l y or i n d i r e c t l y , upon b a c t e r i a as a source of n u t r i t i o n , e i t h e r through a c t u a l consumption of the b a c t e r i a or a b s o r p t i o n of compounds r e l e a s e d by them o r by o t h e r s of the l a r g e r organisms p r e s e n t . Microthamnion was never found i n e x t r e m e l y h i g h con-c e n t r a t i o n i n the l e a v e s and was not as f r e q u e n t l y or as c o n s i s t e n t l y found as c e r t a i n of the o t h e r organisms p r e s e n t , such as r o t i f e r s and m i t e s . I t i s the o n l y green a l g a which was o b s e r v e d i n s i g n i f i c a n t c o n c e n t r a t i o n . I t may be noted here t h a t t h i s genus produces b i f l a g e l l a t e zoospores v ? r i t s c h ( * 4 f i ) ) which may have been r e c o r d e d as f l a g e l l a t e s . T h i s s p e c i e s i s r e p o r t e d by P r e s c o t t ('62) to be a common s p e c i e s i n sphagnum bogs and o t h e r watery l o c a t i o n s w i t h h i g h o r g a n i c c o n t e n t . C e r t a i n l y the p i t c h e r l i q u i d can be s a i d t o 24 have h i g h o r g a n i c c o n t e n t , and v e r y l i k e l y Microthamnion i n v a d e s the l e a f from the bog i t s e l f , b e i n g s p l a s h e d i n by r a i n or c a r r i e d i n by f l i e s . The l e a f i s l i n e d v/ith b r i s t l e s f o r some o f i t s l e n g t h so t h e r e would be a f a i r l y l a r g e s u r f a c e a r e a a v a i l a b l e t o the a l g a f o r attachment; F r i t s c h n o t e s t h a t t h i s genus may be found f r e e - f l o a t i n g as the a l g a ages. R o t i f e r s were observed i n a l l the l e a v e s except on a t one time or a n o t h e r , but i n o n l y f o u r ( H a , I b , I l l b and l i e ) were th e y found throughout the f u l l 30 days. I t s h o u l d be n o t e d t h a t a l l r o t i f e r s were from the same genus i n the l e a v e s observed o u t s i d e , or a t l e a s t c l o s e l y a l l i e d genera. T h e i r g e n e r a l appearance was i d e n t i c a l , and i n d i v i d u a l s d i f f e r e d o n l y i n s i z e . However, i n the l e a v e s and tubes observed i n the l a b o r a t o r y t h e r e were s e v e r a l d i f f e r e n t genera p r e s e n t . The o n l y e x p l a n a t i o n f o r t h i s which suggests i t s e l f i s t h a t the p l a n t s had been away from the bog f o r a y e a r and had spent s i x months i n d o o r s . These a r e abnormal c o n d i t i o n s f o r a p i t c h e r p l a n t and i t may not have been d e v e l o p i n g n o r m a l l y , o r , as the case may be, s e c r e t i n g s u b s t a n c e s i t would n o r m a l l y have s e c r e t e d . F u r t h e r , b e f o r e the s t u d y was s t a r t e d the l e a v e s were t h o r o u g h l y washed. T h e r e f o r e , any s e c r e t i o n s p r e s e n t would not be t h e r e when the l e a v e s were i n o c u l a t e d so t h a t the microecosystem which dev e l o p e d i n the l e a f would more n e a r l y p a r a l l e l one i n a t e s t tube than one i n a p i t c h e r p l a n t l e a f under normal c i r c u m s t a n c e s , and many d i f f e r e n t k i n d s o f r o t i f e r s are 2 5 n o r m a l l y found i n the former. The o t h e r obvious d i f f e r e n c e between the l e a v e s grown o u t s i d e and those i n the l a b o r a t o r y i s t h a t the s p e c i e s d i v e r s i t y i n the l a b o r a t o r y p l a n t s was e x t r e m e l y s m a l l . The o n l y organisms ever a p p e a r i n g i n s i g n i f i c a n t numbers were Tetrahymena, r o t i f e r s and m i t e s . No Microthamnion was observed, nor P o l y t o m e l l a , nor lOp. rounds, nor any o t h e r c i l i a t e s . The communities i n the tubes were even more ex-treme than t h i s . In tube 3, to which a f l y was added, a s i g n i f i c a n t l y l a r g e p o p u l a t i o n of Tetrahymena developed, however the p o p u l a t i o n of t h i s organism i n l e a v e s 1 and 4 t o which f l i e s were a l s o added developed about t e n times the c o n c e n t r a t i o n as i n the tube. Furthermore, the two l e a v e s which d i d not r e c e i v e a f l y c o n t a i n e d almost as many organisms as the tube which d i d , w h i l e the tubes which d i d not were almost b a r r e n o f l i f e . T h i s s t r o n g l y s u ggests t h a t the l e a f s e c r e t e s s u b s t a n c e s which are b e n e f i c i a l t o c e r t a i n organisms, e i t h e r d i r e c t l y o r i n d i r e c t l y , more than l i k e l y compounds which can se r v e as a s u b s t r a t e f o r b a c t e r i a which may then s e r v e as a f o o d source f o r the o t h e r s p e c i e s p r e s e n t . I n f a c t , i t i s known L l o y d ('42) t h a t the l e a f has s e v e r a l g l a n d u l a r r e g i o n s a l o n g i t s l e n g t h , a l t h o u g h the n a t u r e of the s e c r e t i o n s i s unknown. The microcosm i n a p i t c h e r p l a n t l e a f i s an i d e a l m i n i a t u r e ecosystem. B e i n g s m a l l i n s i z e i t can berbrdught i n t o the l a b o r a t o r y , t r a n s p o r t e d e a s i l y , h a n d l e d c o n v e n i e n t l y and sampled w i t h a minimum of d i f f i c u l t y . I t i s a l s o 26 n a t u r a l l y occurring and harbors several species which are adapted to t h i s p a r t i c u l a r habitat (mites, mosquito larvae, f l y l a r v a e ) , as w e l l as others which have a le s s s p e c i f i c niche (Tetrahymena, Microthamnion, Polytomella). I t can be studied i n the f i e l d or a r t i f i c i a l conditions can e a s i l y be imposed upon the system to simulate natural phenomena such as exclusion, overgrazing, geographical i s o l a t i o n , e x t i n c t i o n of a species, climax assemblages under d i f f e r e n t conditions, invasion by a new species, e t c . , which may occur i n t h i s or any other e c o l o g i c a l system. 27 SUMMARY A study was made on the leaves of the p i t c h e r plant, Sarracenia purpurea to determine the usefulness of these microecosystems i n the i n v e s t i g a t i o n of broad e c o l o g i c a l concepts. A survey was made of the organisms present i n the leaves and the t o t a l biomass and oxygen consumption of the major species observed over a period of t h i r t y days were graphed. A laboratory study on leaves and tubes was c a r r i e d out and the r e s u l t s compared with those obtained from plants grown outdoors. Findings were as follows: 1. There were three organisms observed i n the leaves which are known?to be t y p i c a l of t h i s species of pi t c h e r plant, two during t h e i r l a r v a l stages and one f o r i t s e n t i r e l i f e c y c l e . The p o s s i b i l i t y e x i s t s that some of the other species present may be indigenous to t h i s plant as w e l l . 2. Paramecium may be excluded from t h i s as well as at l e a s t one other carnivorous plant. 3. I t i s suggested that Microthamnion i n h i b i t s the growth of Tetrahymena, probably through some extrametabolite. 4. Yeasts and copepods were always observed i n the same leaves, suggesting a p o s i t i v e c o r r e l a t i o n between the two, however c l o s e r examination of the data i n d i c a t e s the r e v © 2 » reverse. No explanation was of f e r e d . 5. No predator-prey i n t e r a c t i o n was observed, i n p l y i n g the dependence of the e n t i r e ecosystem upon the b a c t e r i a as nu t r i e n t source, e i t h e r d i r e c t l y or i n d i r e c t l y . 6. One species of r o t i f e r was observed i n the plants i n the 28 f i e l d , while several species were found i n those grown i n the laboratory. I t i s suggested that t h i s i s due to the unnatural conditions of growth of the plants i n the laboratory. 7. A_imajor diff e r e n c e between the laboratory plants and the f i e l d plants was a r e l a t i v e l y extremely low species d i v e r s i t y i n the former. The tubes showed much the same species d i v e r s i t y as the leaves i n the laboratory but had f a r lower t o t a l numbers. 8. The leaves of p i t c h e r plants have immense p o t e n t i a l i n the study of ecology, due l a r g e l y to t h e i r n a t ural occurrence and small s i z e . 29 Figure 1. Counting chamber, 1. Small cover glass 2. Plexiglas tube 3. Large cover glass 4. Vaseline Figure 1. F i g u r e 2. S t a t i s t i c a l t e s t ( F t e s t ) on randomness of sampling,, A l l samples f a l l i n t o the range o f a c c e p t a b i l i t y except one, which i s a b o r d e r l i n e c a s e . T h e r e f o r e , sampling i s assumed t o be random. L e a f Tube R o t i -f e r s x=15.2 S =8.7 F=0.57 X=13.8 S =3.7 F=0.27 x=9.6 F=1.23 S 2=11.8 x=9.4 S =1.8 F=0.20 x=101.6 S =203.3 F=2.0 T e t r a -hymena x=102 S =443.0 F=4.34 x=21 F=0.48 S 2=10.0 x=25.0 S =25.0 F=1.0 F ( 5 o o ) = 2 , 5 6 6 5 i 5 ^ l e v e l o f s i g n i f i c a n c e Figure,: 2. 31 F i g u r e 3. Graph showing the r e l a t i o n s h i p between the d r y weight and oxygen consumption f o r m i c r o -organisms* M o d i f i e d from Hargrave ('69), O £ c c o 10 2 f 10 r 2 10 - 5 O M A C R O F A U N A O T E T R A H Y M E N A y = 0 . 9 5 X 0-74 r = 0 . 9 0 PoLYTOMELLA o O BACTERIA 10 1 ' 1 i « r -10 - 6 10 10 - i r—r—s 1 1 r : 10 1 i c f D r y w e i g h ! (mQ) F i g u r e 3. F i g u r e 4. Ta b l e showing the o c c u r r a n c e of the major organisms observed i n the l e a v e s i n which they appeared. I a H a I l i a IVa Mosquito l a r v a e F l y l a r v a e + • + + + M i t e s + + + Deutonymphs + V + + Copepods R o t i f e r s + + + Tetrahymena + + C h i l o d o n e l l a + + D i s s h e v e l e d + P o l y t o m e l l a + + + Peranema A s s o r t e d f l a g e l l a t e s . + + + + Amoebae + + Microthamnion + + + Diatom + 10u rounds + + + M u l t i n u c l e a t e s + Y e a s t s F i g u r e 4. LEAVES Ib l i b I l l b IVb I c H e I I I c IVc + + + + + + + + + + + + + + + + +' .; + + + + + + + + + + + + + + + + + + + + + . + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + •+ + + + + + + + + 33 Key to symbols and colors used in figures 5 - 4 5 . Mosquito larvae . .X Fly larvae L — — — • Mites I Deutonymph A Copepods H Rotifers 0 Tetrahymena E Chilodonella R Dissheveled V Polytomella F Peranema U Assorted flagellates G Amoebae. B Microthamnion C Diatom T 10u rounds M Multinucleates N 01 c n TIME (DAYS) Figure 7, Biomass curves f o r l e a f I l i a I O 9 TIME (DAYS) Figure 9. Biomass curves f o r l e a f Ib 9 ioJ + IS) J L F G +•—I r r H 1 1 h o TIME (DAYS) Figure 10. Biomass curves for leaf l i b to 0 10 20 ,TIME (DAYS) Figure 14. Biomass curves f o r l e a f l i e 9 10 a TIME (DAYS) Figure .15. Biomass curves f o r l e a f I I I c 10" to is M m S o > m < ZD M CQ 10 (5) 0 1 ft 1 1 B 1 1 H 1 h H 1 h 10 20 TIME (DAYS) F i g u r e 17. Biomass curves f o r l e a f 1 -\ 1 h ,9 + 0 E I T 0 • — H H h 10 TIME (DAYS) Figure 1 8 . Biomass curves f o r l e a f 2 10 9 + to TS O > co 10 0 Figure 1.9. • • I H H 1 h — f -10 TIME (DAYS) Biomass curves f o r l e a f 3 20 H 1 r 4k 1—r -f H h H 1 I-10 20 TIME (DAYS) Figure 2 1 . Biomass curves f o r tube 1 i o 9 + B 1 1 © 10 TIME (DAYS) Figure 2 2 . Biomass curves f o r tube 2 0 10 TIME (DAYS) F i g u r e 2 3 . B iomass c u r v e s f o r t u b e 3 - t r © 1 1 o H h H h H 1 h 10 20 TIME (DAYS) Figure 24. Biomass curves f o r tube 4 0 10 20 30 TIME (DAYS) Figure 25. Oxygen consumption curves f o r l e a f Ia 0 10 20 30 T I M E (DAYS) Figure 32. Oxygen consumption curves for leaf IVb. o c ro w o X o o H- ° O 3 o c 1 H <! M ro *z o c t— in ro ' H> M o to o OJ o 0 cn 0 ul OXYGEN/ANIMAL""1/IIOUR"1 © r I—I H r z z > H LT) cn D I m \ / F l \ m S9 £9 10 J — I I c M M \ < SB Ed GR >* X o 10 -4 • H + H h—1 1 h 10 20 TIME (DAYS) Figure 37. Oxygen consumption curves f o r l e a f 1 30 IO 1 t ® E ® • E n D >-4 0 L j H 4 H 10 —I 1 h 20 H h H 1-30 TIME (DAYS) Figure 38. Oxygen consumption curves f o r l e a f 2 -0 0 10 20 30 TIME (DAYS) 2 oo Figure 39. Oxygen consumption curves f o r l e a f 3. E : n H 1 + E © • CX E CD H h f- H 1 h 0 10 20 TIME (DAYS) Figure 40. Oxygen consumption curves f o r l e a f 4. 30 IO 1 t .-4 @ H 1 h n H F H 1 r H 1 1— H F H h 0 10 20 30 TIME (DAYS) Figure 41. Oxygen consumption curves for tube 1. ,-4 o © H h—I h— H 1 1 4-—H 0 10 20 30 TIME (DAYS) F i g u r e 42. Oxygen consumption c u r v e s f o r tube 2 I O 1 ,-4 • H f r • / • + 1 r 0 1° TIME (DAYS) F i g u r e 43. Oxygen consumption curves f o r tube 3. 10 J 3 o y a >-< x o © 10" H—f H 1 h 0 D TIME (DAYS) Figure 44. Oxygen consumption curves f o r tube 4. 2 0 3 0 •si Figure 4 5 . Several p i t c h e r p lants (Sarracenia purpurea) i n a p l a s t i c wash b a s i n . 45 Figures 46 - 51. Large organisms found i n the leaves. Sizes as shown. Figure 46. Mite, Anoetus g i b s o n i . Figure 47. Deutonymph stage of A. gibs o n i . Figure 48. Chironomid larvae, p o s s i b l y Metriocnemus. Figure 49. Mosquito l a r v a , probably Wyeomia s m i t h i i . Figure 50. Harpacticoid copepod and r o t i f e r . Figure 51. R o t i f e r , contracted. 76 Figures 52 - 61. C i l i a t e s . Sizes are ind i c a t e d by a lO^i l i n e on each photograph. Figure 52. C h i l o d o n e l l a . Figure 53. Tetrahymena. Figure 59. U n i d e n t i f i e d c i l i a t e which occurred i n s i g n i f i c a n t numbers and i s shown on the graphs as V. Figures 54 - 58 and 60 - 61. C i l i a t e s which occurred i n f r e q u e n t l y and i n low numbers. 77 Figures 62 - 75. F l a g e l l a t e s . Figure 62. Polytomella. 62a, view from beneath. 62b, side view. I Figure 63. Peranema. Figures 64 - 75. U n i d e n t i f i e d c i l i a t e s which i n d i v i d u a l l y occurred i n f r e q u e n t l y and i n low numbers. Figures 76 Figure 76. Figure 77. Figure 78. Figure 79. 79. Amoebae. S h e l l of A r c e l l a . Amoeba radiosa. A. gu t t u l a . A. s t r i a t a . Figures 80 & 81. Algae. Figure 80. Microthamnion. Figure 81. Diatom. 80 80 Figures 82 - 84. Assorted miscellany. Figure 82. 10u rounds. Figure 83. Multinucleates, p o s s i b l y Actinoraycetes. Figure 84. Yeasts. 81 LITERATURE CITED Dodge, H.R. (1947) A new s p e c i e s of Wyeomia from the p i t c h e r p l a n t . P r o c . E n t . Soc. Wash. 49:117-122. F r i t s c h , F.E. (1945) The S t r u c t u r e and R e p r o d u c t i o n of the A l g a e . Volume I I . Cambridge U n i v e r s i t y P r e s s , Cambridge. Hargrave, B.T. (1969) I n t e r - r e l a t i o n s h i p s between a d e p o s i t -f e e d i n g amphipod and metabolism of sediment m i c r o f l o r a . Ph. D. T h e s i s , U n i v . of B. C. L i b r a r y . Hegner, R.W. (1926) The i n t e r r e l a t i o n s of p r o t o z o a and the u t r i c l e s o f U t r i c u l a r i a . B i o l . B u l l . 50:239-270. Hegner, R.W. (1926) The p r o t o z o a of the p i t c h e r p l a n t ( S a r r a c e n i a purpurea) B i o l . B u l l . 50:271-276. Hepburn, J.S. (1920 & 1927) C i t e d from L l o y d (1942) Hughes, T.E. (1959) M i t e s or the A c a r i . The A t h l o n e P r e s s , London. Hunter, P.E. & C.A.Hunter (1964) A new Anoetus mite from p i t c h e r p l a n t s . P r o c . E n t . Soc. Wash. 66:39-46. Judd, W.W. (1959) S t u d i e s of the Byron bog i n southwestern O n t a r i o . X. I n q u i l i n e s and v i c t i m s of the p i t c h e r p l a n t , S a r r a c e n i a p u r purea ( L . ) . Can. E n t . 91:171-180 K r i s h n a m o o r t h i , K.P. & H.Bick (1966) L a b o r a t o r y s t u d i e s on the s u c c e s s i o n of c i l i a t e s d u r i n g the decomposition of peptone i n r e l a t i o n t o c e r t a i n e n v i r o n m e n t a l f a c t o r s : P a r t s I & I I . World H e a l t h O r g a n i z a t i o n P u b l i c a t i o n No. WHO/EBL/66.83 Kudo, R.R. (1954) P r o t o z o o l o g y . C h a r l e s C.Thomas. S p r i n g f i e l d , I l l i n o i s . L l o y d , F.E. (1942) The C a r n i v o r o u s P l a n t s . C h r o n i c a B o t a n i c a Company, Waltham, Mass. MacKinnon, D.L. & R.S.T.Hawes (1961) An I n t r o d u c t i o n t o the Study o f P r o t o z o a . O x f o r d Univ. P r e s s , London. Maguire, B., J r . (1963) The e x c l u s i o n o f Colpoda ( c i l i a t a ) from s u p e r f i c i a l l y f a v o r a b l e h a b i t a t s . E c o l o g y 44:781-784 M e g l i t s c h , P.A. (1967) I n v e r t e b r a t e Zoology. O x f o r d Univ. P r e s s , T o r o n t o . P a u l i a n , R. (1963) An a c a r i n a ( C r e u t z e r i a t o b a i c a ) o f p i t c h e r s of Nepenthaceae. C i t e d from B i o l . Abs. 43:16732 82 P h i l i p , C.B. (1953) Notes on T a b a n i d f l i e s and o t h e r v i c t i m s caught i n the c a r n i v o r o u s p l a n t , S a r r a c e n i a f l a v a . C i t e d from B i o l . Abs. 27:12029. P r e s c o t t , G.W. (1962) Algae of the Western Great Lakes A r e a . Wm. C.Brown Co., Dubuque, Iowa. P r i c e , R.D. (1958) Notes on the b i o l o g y and l a b o r a t o r y c o l o n i z a t i o n o f Wyeomia s m i t h i i ( C o q u i l l e t t ) ( D i p t e r a : C u l i c i d a e ) . Can. E n t . 90:473 Sorenson, D.R. & W.T. J a c k s o n (1968) The u t i l i z a t i o n o f Paramecia by the c a r n i v o r o u s p l a n t , U t r i c u l a r i a g i b b a . P l a n t a 83:166-170. T i f f a n y , L.H. & M.E. B r i t t o n (1952) The Algae of I l l i n o i s . U n i v . of Chicago P r e s s , C h i c a g o . Zeuthen, E. (1953) Oxygen uptake as r e l a t e d t o body s i z e i n organisms. Quart. Rev. B i o l . 28:1-12. 

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