Journal of Threatened
Taxa | www.threatenedtaxa.org | 26 February 2023 | 15(2): 22686–22694
ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print)
https://doi.org/10.11609/jott.8287.15.2.22686-22694
#8287 | Received 28 November 2022 | Final received 02 January 2023 |
Finally accepted 09 February 2023
Andromonoecy functional through
heterostyly and large carpenter bees as principal pollinators in Solanum carolinense L. (Solanaceae)
Suvarna Raju Palathoti
1 & Aluri
Jacob Solomon Raju 2
-1 Department of
Health, Safety and Environmental Management, International College of
Engineering and Management, Muscat, Sultanate of Oman, Oman.
2 Department of Environmental
Sciences, Andhra University, Visakhapatnam, Andhra Pradesh 530003, India.
1 suvarnarajup@rediffmail.com, 2
solomonraju@gmail.com (corresponding author)
Abstract. Solanum carolinense is a perennial shrubby weed. In
this species, andromonoecy is functional through heterostyly represented by the
production of long, semi-long, medium, & short-styled flower types and
another flower type lacking style & stigma completely. All plants produce
long-styled flowers while all individuals do not produce other flower types.
The long- and semi-long-styled flowers are functionally co-sexual and produce
fruit while the other flower types are functionally female-sterile and do not
produce fruit. The position of style in long- and semi-long-styled flowers
facilitates the act of pollination by pollinator bees. Xylocopa
bees are large-bodied specialist bees which collect pollen from poricidal
anthers efficiently in this plant by displaying buzzing behaviour
and are treated as principal pollinators. The other bees are small-bodied and
do not display buzzing behaviour to release pollen
from poricidal anthers but they simply collect residual pollen available around
the rim of the apical pore of the anthers, and hence they act as supplementary
pollinators only. In this plant, the style length has a positive relationship
with pollen deposition and a negative relationship with pollen removal in
flowers visited by large carpenter bees of Xylocopa
genus and hence, pollinator-specific interactions with flower morphology are
important in the maintenance and perfect evolution of andromonoecy in this
plant species. Florivory by Mylabris
pustulata could vary with the flower production
rate in S. carolinense and could favor higher
floral-sex ratios biased in favour of higher
proportion of female-sterile flowers.
Keywords: Buzz-pollination, female-sterile
flowers, florivory, indehiscent berry nectar-less
flowers, poricidal anthers.
Editor: Anonymity
requested. Date of
publication: 26 February 2023 (online & print)
Citation: Palathoti,
S.R. & A.J.S. Raju (2023). Andromonoecy functional through heterostyly and large carpenter
bees as principal pollinators in Solanum carolinense
L. (Solanaceae). Journal of Threatened Taxa 15(2): 22686–22694. https://doi.org/10.11609/jott.8287.15.2.22686-22694
Copyright: © Palathoti & Raju 2023. Creative Commons Attribution
4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: Self-funded.
Competing interests: The authors
declare no competing interests.
Author details: Prof. A.J. Solomon Raju
is honorary professor, Department
of Environmental Sciences, Andhra
University, Visakhapatnam, India. Dr. P. Suvarna Raju is assistant
professor, Department of Health, Safety and Environmental Management,
International College of Engineering and Management,
Muscat, Sultanate of Oman, Oman.
Author contributions:
Both authors
contributed equally.
Acknowledgements: We thank the Andhra University,
Visakhapatnam, for providing physical facilities to carry out this research
work.
INTRODUCTION
The family Solanaceae has about
100 genera consisting of 2,500 species distributed world over with species
diversity centered in America, Australia, and Africa (Olmstead et al. 1999,
2008). Species of this family have enormous importance as food plants the world
over. Crops such as potato, tomato, and capsicum in Solanaceae family are
important staple vegetables although there are many other species which are
important as edible products (Samuels 2009). In India, this family is
represented by 29 genera with 116 species, two sub-species, three varieties,
and one forma (Kumari 2004). Of these, 12 genera with
39 species are distributed in the Eastern Ghats region (Venkatappa
2011). In this family, Solanum with about 1,500 species is one of the
largest genera distributed throughout the world (Vorontsova
et al. 2013). In India, this genus is represented by 49 species which are
distributed throughout the country, of which 17 species occur in the Eastern
Ghats region (Venkatappa 2011).
Andromonoecy is more common in
Solanaceae family and it is well documented in Solanum genus (Vorontsova et al. 2013). In Solanum genus, a number
of species display andromonoecy and dioecy as functional sexual systems. In
vast majority of dioecious species, the female flowers produce pollen-bearing
anthers but the pollen is inaperturate, viable and does not produce a pollen
tube while male flowers produce pistils with ovules (Martine & Anderson
2006). In andromonoecious species, the staminate
flowers produce variously or noticeably reduced pistil because the style is
short to place the stigma above the staminal column. As a result, the stigma is
unable to receive pollen directly from the pollinating bees but there is a
possibility for incidental gravitational pollination from pollen puffed into
the air in the space between anthers by the sonicating action of probing bees (Vorontsova et al. 2013). Andromonoecism
is functional in species pollinated by bats, bees, flies, hummingbirds, and
moths (Bawa & Beach 1981). Heithaus
et al. (1974) stated that andromonoecy is evolved to selective pressure for
increasing cross-fertilization. Zapata & Arroyo (1978) mentioned that andromonoecism is a result of abortion of non-functional
pistils in certain flowers that serve as male or attraction functions before
their anthesis. These authors suggested three possibilities as to the
significance of pistils in bisexual flowers that largely serve as pollen
donors. First, the abortion of pistils could structurally perturb the floral morphology,
disrupting the pollination mechanism. Second, the abortion of pistils in many
bisexual flowers prior to pollination could restrict the efficacy of selection
on progeny acting through control over pollen germination, tube growth, and
embryo & fruit abortion. Third, the abortion of pistils may not occur in
most hermaphroditic species because it is not possible to predict the fate of
flowers as pollen donors or pollen recipients before pollination (Lloyd 1980).
Different authors reported on the
sexual system and pollinators of Solanum carolinense.
It is an andromonoecious species with
hermaphrodite and male flowers on the same individual (Bertin
1982). The anthers in staminate and hermaphroditic flowers are of the same size
and produce the same quantity of pollen but they display some specialization in
each flower sex (Connolly & Anderson 2003). The long-styled flowers serve
primarily as pollen recipients while short-styled flowers as pollen donors
(Quesada-Aguilar et al. 2008). It is self-incompatible but it is flexible as a
part of stable mixed mating system which permits self-fertilization when
cross-pollination limits seed production in situations of establishing new
populations as a weed (Kariyat et al. 2011). It is
pollinated by different bees in different regions of USA (Hardin et al. 1972;
Quesada-Aguilar 2001; Connolly & Anderson 2003; Travers et al. 2004;
Vallejo-Marin & Rausher 2007). With this
backdrop, the intent of the present study is to evaluate whether only long- and
short-styled hermaphrodite flower types occur or other hermaphrodite flower
types with variation in style length also occur with different sexual functions
in S. carolinense. Further, the study also
aims at providing additional information on its fruiting aspects and florivory. Since there is not even a single report on the
sexual system and pollinators of S. carolinense
from India, this study is an attempt to provide the details of sexual
reproduction and fruiting aspects functional through local pollinators and
compare the same with the reports published from outside India.
MATERIALS AND METHODS
Flowering season, floral
morphology, and biology
Solanum carolinense population growing in the wild
pockets of Madhurawada area of Visakhapatnam city (17049’20.8992”N
& 83021’8.0028”E), Andhra Pradesh, India, was used for the
present study during May–December 2021. This plant population was observed for
its flowering season, anthesis and anther dehiscence mode, flower visitors and
their foraging behavior, pollination, natural fruit, and fruit aspects. The
population was followed continuously during the study period for the flowering
intensity levels to classify into initial, peak, and fag end of flowering.
Twenty-five just open flowers were used to record the floral details. Anthesis
schedule and anther dehiscence timing were recorded by tagging and following 25
marked mature buds in the field. Flowers were classified into five types
according to style length and the absence of style and stigma. A total of 211
flowers collected randomly from ten plants were used to calculate the
percentage of plants producing each flower type and the production rate of each
flower type. Morphological aspects of these flower types are briefly described.
Twenty undehisced anthers from each flower type on
ten plants were used to determine pollen output and study pollen grain
characteristics as per the protocols given in Dafni et al. (2005).
Foraging behavior and pollination
Flowers visitors included
exclusively bees and they were listed along with forage sought, foraging
schedule and the total number of foraging visited made per day. Their foraging
activity pattern during day-time was observed in the field. The hourly foraging
visits of each bee species were recorded on four different days during peak flowering
phase. The average number of foraging visits made by each bee species at each
hour was noted to present the foraging activity pattern of bees. The species
were identified by tallying with the reference species collected from the study
region and identified by Zoological Survey of India, Calcutta. Further, the
same data were used to calculate the percentage of foraging visits of each bee
species per day in order to understand the relative foraging activity levels of
each bee species. The bees were observed carefully for their foraging behavior
such as mode of approach, landing, probing behavior employed for pollen
collection and contact with essential organs in effecting pollination.
Florivory
The blister beetle Mylabris pustulata (Thunberg,
1821) was found feeding on the flowers. Keeping this in view, a sample of 100
flowers was chosen at the initial, peak and fag-end of flowering phase to
record the percentage of flowers fed by this beetle. Further, the floral parts
fed by this beetle were recorded to know whether the flowers used by them have
any role in fruit set.
Natural fruit set and fruiting
ecology
Twenty-five fertilized flowers
that showed initial growth of fruit development were tagged and followed to
record the duration of fruit development and maturation. Fruit set rate was
recorded only in long and semi-long flowers since the other flower types did
not initiate and develop fruits. Fifty flowers of each flower type were tagged
and followed to record fruit set rate in open-pollinations. Fruit characters
were also recorded.
RESULTS
Flowering season and floral
morphology
It is a small perennial shrubby
weed. The stem and underside of larger leaf veins are covered with prickles.
Leaves are petiolate, arranged alternately to each other; they are elliptic to
oblong, irregularly lobed and the upper and lower surface is covered with fine
hairs. The plant propagates by underground rhizome and seed. The plants
emerging from the rhizome appear producing new aerial stalks and foliage with
the onset of wet season in June and initiate flowering by late July while those
emerging from seed produce full-grown plants by late July and begin flowering
by second week of August. The flowering continues without a break until late
October and gradually ceases by second week of November (Image 1a). In
year-long wet locations, plants display vegetative growth, flowering and
fruiting simultaneously or alternately throughout the year. The flowers are
produced in terminal and axillary cymes (Image 1b). The flowers are
medium-sized, non-tubular, white, odorless and actinomorphic. They are
morphologically bisexual but functionally either bisexual or female-sterile.
The style length varies but the length of stamens remains unchanged in all
flowers borne on the same individual. According to style length, the flowers
are classified into four types, long-styled (Image 1d), semi-long-styled (Image
1e), medium-styled (Image 1f), and short-styled ones (Image 1g). Further,
another flower type with pistil lacking style and stigma (Image 1h) is also
produced along with these four types of flowers in the same individual. All
individuals produce long-styled flowers but semi-long-styled flowers are
produced only in 75%, medium-styled flowers in 83%, short-styled flowers in 75%
and flowering lacking style and stigma in 67% of the total monitored plants
(Figure 1). Of the total flowers observed in monitored individuals, 59% are
long-styled, 11% semi-long-styled, 10% short-styled, 9% short-styled flowers
and 11% flowers lacking both style and stigma (Figure 2). In all flower types,
the calyx has five green pointed spiny sepals and is quite inconspicuous. The
corolla is rotate bearing five spreading lobes with yellow center and is quite
conspicuous. The stamens are five with short filaments and large, non-adherent
yellow anthers inserted on the corolla and form a cone around the pistil; there
is no variation in the length of filament and anthers in all flower types. The
style is long, extends beyond the length of stamens, it is strikingly sub-capitate.
The ovary is bulbous and bears numerous ovules (Image 2b).
Floral biology
The flowers are open daily during
0600-0830 h (Image 1c). The corolla expands and its lobes become flat exposing
the anthers as a single unit. All anthers in individual flowers dehisce
simultaneously by apical pores. All five flower types produce the same amount
of pollen; it is 19,246 ± 346.4 per anther. The pollen grains are dry, powdery,
yellow, spheroidal to sub-prolate, tricolporate and
27.39 ± 4 µm in size (Image 2a). The pollen release occurs through apical pores
of the anthers when flower foragers exhibit buzzing behavior to collect pollen
and in the absence of flower foragers, the pollen remain inside the anthers and
is not self-exposed or released. The nectar disc is absent and hence nectar is
not produced. As a result, the flowers offer pollen as exclusive reward for the
probing insects.
Foraging behavior and pollination
The flowers were visited by five
bee species, namely, Apis cerana, Trigona iridipennis, Xylocopa
latipes, X. pubescens,
and Nomia sp. during day time from 0700 to
1700 h (Table 1). These bees showed a gradual increase in foraging activity
from morning and until noon and then a gradual decrease towards evening hours
(Figure 3). Of these bees, Xylocopa bees
exhibited buzzing behavior to collect pollen from the poricidal anthers (Image
2c–f). The buzzing length was relatively very less at the fresh flowers and its
length increased gradually with a gradual decrease in the amount of pollen in
the anthers. Accordingly, the pollen quantity in anthers gradually decreased
from morning to evening. These bees upon landing on the anthers, grasped the
latter with their hind legs, rotated on the flower to handle each anther
separately to collect pollen. In this process, they performed vibrations with
their wings by producing audible buzzes. Then, the pollen was released as puffs
from the apical pores of the anthers and it is dispersed into the air
surrounding the stigma in case of long- and semi-long-styled flowers.
Sometimes, the pollen-laden ventral side of the bee body came into contact with
the stigma resulting in pollination. Some pollen gradually descended through
narrow spaces between the anthers in all other flower types. The flowers that
were visited by these bees showed bruise marks on the anthers and these marks
were taken as indicators of bee visits that buzz the flowers. Large mass of
pollen was visible on the hind legs of the bees visiting the flowers. The other
bees, Apis cerana,
Trigiona iridipennis,
and Nomia sp. did not show buzzing
behavior to handle anthers to collect pollen from apical pores but they simply
gathered pollen on and around the rim of the apical pores and in this process,
they were able to come in contact with the stigma in long- and semi-long-styled
flower types effecting pollination (Image 2g–i). But
the contact between the ventral side of the bee body and the stigma in these
two flower types was found to be dependent on the posture used by the bees
while gathering pollen. All bees were consistent and regular in utilizing the
pollen from this plant during its peak flowering season. Only Xylocopa bees displayed fidelity to the flowers of
this plant throughout its flowering season while all other bees paid visits to
its flowers occasionally only. Of the total foraging visits made by bees, Xylocopa bees accounted for 54% and all other bees
46% during peak flowering period (Figure 4). Therefore, Xylocopa
bees were found to be appropriate foragers and hence are the principal
pollinators while other bees are only supplementary pollinators for the plant.
Florivory
The common blister beetle, Mylabris pustulata
(Image 2j) was found feeding on the corolla, stamens, style and stigma (Table
1). Florivory by this beetle stood at 31% during peak
flowering phase and at 8–9% in the initial and fag-end of flowering season.
This phenomenon appears to have a detrimental effect in the plant for the
success of its sexual reproduction.
Natural fruit set and fruiting
ecology
Initiation of fruit development
occurs as soon as flowers are fertilized and mature and ripe fruits form within
a month (Image 2k–n). In open-pollinations, fruit set occurs only in long- and
semi-long-styled flower types only. Fruit set is 88% in long-style flower type
and 45% in semi-long-styled flower type (Table 2). Fruit is an indehiscent,
many-seeded berry; it is dark green when immature and scarlet-orange when
mature. The calyx encloses the berry completely throughout the course of its
development and maturation. But, the calyx lobes gradually separate and
partially unfold exposing the ripe berry.
DISCUSSION
In this species, the role of
androecium is different in hermaphrodite and male flowers. In both flower
sexes, the anthers are of the same size and produce the same quantity of pollen
but display some form of specialization in each flower sex. The anthers of male
flowers act primarily as possible near-distance attractors and as pollen donors
while hermaphrodite flowers act primarily as pollen recipients and as pollen
donors (Connolly & Anderson 2003). In another report, S. carolinense is stated to be andromonoecious
and functional through long-styled and short-styled flowers; the former type
serves primarily as pollen recipient while the latter type as pollen donor
(Quesada-Aguilar et al. 2008). S. carolinense
is self-incompatible but it is flexible as a part of stable mixed mating system
which permits self-fertilization when cross-pollination limits seed production
in situations of establishing new populations (Kariyat
et al. 2011). In the present study also, S. carolinense
is found to be andromonoecious but this sexual system
is functional through heterostyly involving long, semi-long, medium, &
short-styled flower types and also another flower type lacking style &
stigma completely. All these flower types are present together on the same
plant. All individuals produce long-styled flower type while other flower types
are not produced by all individuals. The long- and semi- long-styled flowers
are functionally co-sexual and produce fruit while the other flower types are
functionally male or female-sterile and do not product fruit. The style is
placed slightly above the anthers in semi long-styled flowers while it is
placed comparatively far above the anthers in long-styled flowers. Such a
placement of the style in these flower types facilitates and ensures the
occurrence of pollination by specialized pollen collecting bees. In medium- and
short-styled flower types, the style is not exposed and enclosed by
conical-shaped anthers; there is no scope for contact between the style and
pollen collecting bees in these flowers. In flowers lacking style and stigma,
the question of pollinator contact with these sex organs does not arise at all.
The heterostyly condition functional through andromonoecy appears to have
evolved in response to the limitation of nutrients and the production of extra
functionally male flowers against functional co-sexual flower types appears to
be an indication of resource constraints under which fruit production is most
unlikely (Whalen & Costich 1986; Diggle 1991;
Meagher 1992). The production of female-sterile flowers is cheaper to produce
than perfect flowers and the resources saved by them are not re-allocated to
other fitness enhancing functions. The principal morphological trait of
female-sterile flowers is pistil reduction which does not increase either
pollinator visitation or siring success of open-pollinated flowers
(Vallejo-Marin & Rausher 2007). The production of
female-sterile flower type completely lacking style and stigma is a functional
step in the evolution of perfect male flowers and also an indication of
resource constraints for enhancing fruit production. Therefore, the flowers
that present style above anthers are functionally co-sexual and fruit producing
while the flowers that present style within the anthers or that lack style and
stigma are functionally female sterile or male.
In flowering plants, most of the
species exhibit longitudinal and poricidal mode of anther dehiscence; in the
former mode, pollen is presented along the line of dehiscence and its
collection does not require special skills from pollinators while in the latter
mode, pollinators require special skills to squeeze the anthers by special
buzzes or vibrations in order to collect pollen from the apical pore. In
flowers with poricidal anthers present only pollen as the reward and hence
pollen collecting insects that exhibit buzzing behavior can only collect this
reward while other foragers either visit and subsequently depart from such
flowers or do not visit such flowers at all (Buchmann 1983). Different authors
(Hardin et al. 1972; Quesada-Aguilar 2001; Connolly & Anderson 2003;
Travers et al. 2004; Vallejo-Marin & Rausher
2007; Quesada-Aguilar et al. 2008) reported that S. carolinense
is pollinated by bees in USA. It is pollinated by pollen-gathering bees which
display buzzing behavior, Lasioglossum spp.,
Augochloropsis metallica,
and Bombus impatiens. In the present
study, S. carolinense flowers display
poricidal mode of anther dehiscence and pollen production is copious in
poricidal flowers. The carpenter bees employ buzzing or vibration behavior to
extract pollen from poricidal anthers by means of vibrations of the wing
muscles. Since the pollen is dry and powdery, the carpenter bees collect it
with great ease (Buchmann et al. 1989). All other bees recorded on S. carolinense do not exhibit buzzing behavior but simply
gather pollen from the rim of the apical pores of the anthers. The study shows
that there appears to be a positive relationship between the style length and
pollen deposition and a negative relationship between the style length and
pollen removal in flowers visited by carpenter bees. The study shows that the
style length has a positive relationship with pollen deposition and a negative
relationship with pollen removal in flowers visited by carpenter bees. But in
flowers visited by other bees, their morphological or behavioral traits do not
determine pollen deposition or removal. Quesada-Aguilar et al. (2008) reported
similar situation in S. carolinense in which
the style length has a positive relationship with pollen deposition and a
negative relationship with pollen removal in flowers visited by bumble bees.
The morphological or behavioral traits of small halictid bees that visit the
flowers of S. carolinense do not determine
pollen deposition or removal. The study indicates that pollinator-specific
interactions with flower morphology are important in the maintenance and perfect
evolution of andromonoecy in this plant species.
Michael & Christopher (1996)
reported that the caterpillars of the moths, Synanthedon
rileyana Edwards, 1881 and Manduca
sexta Linnaeus, 1763, and the
beetles, Leptinotarsa junca
Germar, 1824 and Epitrix
fuscula Crotch, 1873 feed on S. carolinense. The beetles reduce fruit production to the
extent of 75%. Michael (2007) reported that the weevils, Trichobaris
trinotata Say, 1832 and Anthonomus
nigrinus Boheman, 1843
affect or reduce plant growth and fruit set rate, the former bores into the
stems while the latter feeds on the flowers. Wise & Hebert (2010) reported
that higher levels of florivory and frugivory would favour lower floral-sex ratios biased in favour of lower proportion of male flowers while lower
levels of herbivory would favor higher floral sex ratios biased in favour of optimum percentage of male flowers S. carolinense. In the present study, florivory
by a common blister beetle Mylabris pustulata is found to vary with the flowering intensity
in S. carolinense. However, florivory levels are not high and this situation would
favor higher floral-sex ratios biased in favour of
higher proportion of female sterile flowers. But, florivory
by this beetle could influence the success rate of sexual reproduction.
CONCLUSIONS
In Solanum carolinense, andromonoecious
sexual system is functional through heterostyly involving long, semi-long,
medium and short-styled flower types, and also through another flower type
lacking style and stigma completely. All plants produce long-styled flowers
while other flower types are not produced by all individuals. The long- and
semi- long-styled flowers are functionally co-sexual and produce fruit while
the other flower types are functionally female-sterile and do not product
fruit. The position of style in long- and semi-long-styled flowers the style
facilities the occurrence of pollination by pollinator bees. Xylocopa bees are large-bodied specialist bees which
collect pollen from poricidal anthers in this plant species by displaying
buzzing behaviour and hence are treated as principal
pollinators. The other bees are small-bodied and do not display buzzing behaviour to release pollen from poricidal anthers but they
simply collect residual pollen that is available around the rim of the apical
pore of the anthers, and hence they act as supplementary pollinators only. The
study shows that in S. carolinense the style
length has a positive relationship with pollen deposition and a negative
relationship with pollen removal in flowers visited by Xylocopa
bees and hence, pollinator-specific interactions with flower morphology are
important in the maintenance and perfect evolution of andromonoecy in this
plant species. Florivory by Mylabris
pustulata could vary with the flower production
rate in S. carolinense during its flowering
season and it could favor higher floral-sex ratios biased in favour of higher proportion of female-sterile flowers if
there is persistence of florivory.
Table 1. List of flower visitors
on Solanum carolinense.
Order/ Family |
Insect species |
Forage sought |
Foraging schedule (h) |
Total No. of foraging
visits/day* |
|
Hymenoptera |
|
|
|
|
|
Apidae |
Apis cerana F. |
Pollen |
0700-1700 |
139 |
|
|
Trigona iridipennis Smith |
Pollen |
0700-1600 |
136 |
|
|
Xylocopa latipes Drury |
Pollen |
0700-1700 |
178 |
|
|
Xylocopa pubescens Spinola |
Pollen |
0700-1700 |
195 |
|
Halictidae |
Nomia sp. |
Pollen |
0800-1500 |
30 |
|
Coleoptera |
|
|
|
|
|
Meloidae |
Mylabris phalerata Pallas |
Corolla, stamens, style and
stigma |
0800-1700 |
Resident flower feeder |
|
*Approximately 300 flowers on
closely spaced plants were used to record foraging visits/day by each pollen-
collecting species. The foraging visits indicate mean number of foraging
visits made on four clear sunny days during peak flowering days. |
Table 2. Fruit set rate in
different flower types of Solanum carolinense.
Flower type |
No. of flowers tagged |
No. of flowers set fruit |
Fruit set (%) |
Long styled |
26 |
23 |
88 |
Semi-long-styled |
20 |
9 |
45 |
Medium-styled |
15 |
0 |
0 |
Short-styled |
15 |
0 |
0 |
Ovary lacking style and stigma |
10 |
0 |
0 |
For figures &
images - - click here for full PDF
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