Influence of bee attractants on pollination and yield

The International Journal <strong>of</strong> Plant Reproductive Biology 4(1) pp. 41–46, 2012
<strong>Influence</strong> <strong>of</strong> <strong>bee</strong> <strong>attractants</strong> on pollination and yield parameters in Guava
(Psidium guajava L.)
Anita M.*, V. Sivaram & K. V. Jayaramappa
Laboratory <strong>of</strong> Biodiversity and Apiculture, Department <strong>of</strong> Botany, Bangalore University, Bangalore.
*e-mail : anitam35@yahoo.com
Received : 09.12.2011; Revised : 19.1.2012; Accepted : 22.1.2012
ABSTRACT
The use <strong>of</strong> <strong>bee</strong> <strong>attractants</strong>, Bee-Q, Bee Scent and Fruit Boost in the pollination <strong>of</strong> guava was evaluated. The <strong>bee</strong>
visitation on guava flowers was made for a week, followed by estimation <strong>of</strong> quantitative and qualitative
parameters in fruits. The different concentrations <strong>of</strong> <strong>bee</strong> <strong>attractants</strong> were evaluated to understand the honey<strong>bee</strong>
visitation pattern <strong>of</strong> target crop for improving pollination efficiency. The observations indicate that the best mean
foraging time on guava flowers was observed at 1000 hours (6.78) followed by 1200 hours (4.89) and 1400 hours
st
(3.78) . Bee scent @ 1.5 ml/l (15.67) was the most effective <strong>bee</strong> attractant in increasing <strong>bee</strong> visitation on the 1 day
<strong>of</strong> spray in guava. Bee scent @ 2 ml/l (14.00) significantly attracted higher number <strong>of</strong> <strong>bee</strong> foragers than the
control in guava plots. In addition, the plants sprayed with <strong>bee</strong> <strong>attractants</strong> significantly enhanced the length,
diameter, and weight <strong>of</strong> fruits and total soluble sugars in guava. The present investigation suggests that the <strong>bee</strong>
<strong>attractants</strong> increase marginal percentage <strong>of</strong> <strong>bee</strong> visitation and fruit parameters in guava.
Key words: Psidium guajava, <strong>bee</strong>-<strong>attractants</strong>, honey<strong>bee</strong>, pollination, yield parameters.
Sincere thanks are due to the Department <strong>of</strong> Science & Technology, New Delhi for financial support under the WOS-A Scheme
to one <strong>of</strong> us (AM). We are thankful to Dr. Veenu Kaul, Department <strong>of</strong> Botany, University <strong>of</strong> Jammu, Jammu for suggestions and
comments.
INTRODUCTION
Crop pollination is the most important economic
outcome <strong>of</strong> honey<strong>bee</strong> activities. Planned honey<strong>bee</strong>
pollination is practiced widely to ensure maximized high
quality crop yield. Pollination is closely associated with fruit
set, yield and seed quality. Yields <strong>of</strong> agricultural crops can be
significantly increased through good management practices
and by using effective pollinators (Mec’nichenko 1977).
However preferential visitation <strong>of</strong> pollinators to particular
crop flowers have to be enumerated for efficient pollination
service. Guava (Psidium guajava L.) an important fruit crop
<strong>of</strong> India has gained considerable importance because <strong>of</strong> its
high nutritive value, availability at moderate price, a pleasant
aroma and good flavor. Psidium is a genus <strong>of</strong> about 100
species <strong>of</strong> tropical shrubs and small trees in the myrtle family
Myrtaceae. The flowers are white and slightly protandrous
with five petals and numerous stamens. The flowers are
highly attractive to honey<strong>bee</strong>s producing large amount <strong>of</strong>
pollen and nectar. The fruits are edible and rich in vitamins A,
B, and C. It also contains high amounts <strong>of</strong> calcium which is
unusual in a fruit. Psidium guajava is known to reward <strong>bee</strong>s
with pollen and nectar both being essential for brood growth
and colony development. Guava is highly cross pollinated
crop and pollination by honey<strong>bee</strong>s results in higher fruit
yield (Malo & Campbell 1968, Kumar et al. 1996, Nalawadi
et al. 1996) studied the floral biology <strong>of</strong> Guava and
emphasized the role <strong>of</strong> cross pollination. The number <strong>of</strong>
domesticated honey<strong>bee</strong> colonies in India is decreasing due to
huge number <strong>of</strong> viral diseases and pests. There is a parallel
interest in improving the pollinating efficacy <strong>of</strong> <strong>bee</strong>s and a
pollinator deficit is especially acute if neighboring crops
must compete for limited pollinators (Levin & Anderson
1970). Under conditions <strong>of</strong> compromised pollinator efficacy,
honey<strong>bee</strong> <strong>attractants</strong> may help focus limited pollinators onto
the crop <strong>of</strong> interest (Delaplane & Mayer 2000). Among the

42 January, 4(1)
The International Journal <strong>of</strong> Plant Reproductive Biology
tested <strong>bee</strong> <strong>attractants</strong> based on queen mandibular pheromone
(QMP) (Mayer et al. 1989, Elm Storm & Maynard 1991,
Winston & Slessor 1993, Ambrose et al. 1995, Higo et al.
1995), fruit boost and Bee-Q (based on carbohydrate rich)
have the most promising effect (Currie et al. 1992, Naumann
et al. 1994). Impact <strong>of</strong> <strong>bee</strong> <strong>attractants</strong> in enhancing
pollination and yield has <strong>bee</strong>n reported in cucumber
(Viraktamath & Anagoudar 2002, Pateel & Sattigi 2007),
onion (Kalamath & Sattigi 2002) and radish (Chandrashekar
& Sattigi 2009). Present investigation has <strong>bee</strong>n undertaken
with the aim to evaluate the usefulness <strong>of</strong> some <strong>bee</strong>
<strong>attractants</strong> on pollination efficiency and fruit yield in guava
(Psidium guajava L.).
MATERIALS & METHODS
EXPERIMENTAL LAYOUT — The experiment was
conducted in an agricultural farm located 20 km from
Bangalore, India during 2009-2010. A guava orchard was
identified for the present study. Experimental and Control
trees with row spacing <strong>of</strong> 2 meters were identified and
marked in the farm. The commercially available <strong>bee</strong>
<strong>attractants</strong> like Bee-Q was purchased from M.S Excel
Industries, Bombay; Fruit boost from Pherotech Inc, Delta
BC Canada and Bee Scent from Montana, USA. We
performed attraction experiments to generate treatment
response curves for each pheromone component. Altogether,
we tested three concentrations each <strong>of</strong> Bee-Q (10, 12.5 and
15 g/l), Bee Scent (2, 1.5 and 1ml/l), and Fruit boost (0.5,
0.75 and 1.00 ml/l). For control, the plants were left without
any spray.
TREATMENT ASSIGNMENTS — From each tree
we selected three branches per treatment and they were
labeled with tags separately. The crop area was introduced
with two colonies <strong>of</strong> Apis cerana each having eight frame
populations <strong>of</strong> honey<strong>bee</strong>s (Fig G) and two natural colonies <strong>of</strong>
Apis dorsata and Apis florea were found in the vicinity <strong>of</strong>
experimental site. Bee <strong>attractants</strong> were sprayed on the bloom
<strong>of</strong> guava with a standard sprayer. Bee-Q was applied in the
concentrations <strong>of</strong> 10, 12.5 and 15 g/l/ plot separately.
Different concentrations <strong>of</strong> the <strong>attractants</strong> were used,
because the composition <strong>of</strong> the <strong>bee</strong> <strong>attractants</strong> is different.
However, no <strong>bee</strong> <strong>attractants</strong> were applied to the control plots.
These <strong>attractants</strong> were sprayed on flowers <strong>of</strong> guava during
different intervals (Figs D, E & F) and the number <strong>of</strong>
honey<strong>bee</strong>s visiting the flowers was counted through visual
observation. One observer was assigned to each plot and
observations were synchronized to run between 08.00 to
16.00 hrs at two hourly intervals in a day (Rao &
Suryanarayana 1990). Each observer walked down each row
for five minutes, recording the number <strong>of</strong> honey<strong>bee</strong> flower
visits. A <strong>bee</strong> landing on an open flower for about 5 to 10
seconds was considered to be a ‘visit’. Observations were
th
recorded on first day after spray (12 April, 2009), followed
th
th
by 3rd day (14 April) and 5th day (16 April) after spraying
the <strong>bee</strong> <strong>attractants</strong>. Each observer recorded by sight the
number <strong>of</strong> honey<strong>bee</strong> flower visitors in respect <strong>of</strong> three
species <strong>of</strong> honey<strong>bee</strong>s namely, Apis cerana, Apis florea and
Apis dorsata.
th
HARVEST PARAMETERS — On 14 August, 2009,
the fruits from the earlier tagged flower heads were harvested
from each treatment (Fig H). The mean fruit weight, length
and fruit diameter in treatment was recorded and data were
statistically analyzed. The mean fruit volume <strong>of</strong> five
randomly selected fruits was recorded by using water
displacement method. The total soluble sugars in fruit were
estimated by the hand refractometer.
All the variables were analyzed statistically by using
SPSS version 11.0 with one way ANOVA and a DMRT (Dun
cans Multiple Range Test) with standard errors.
RESULTS & DISCUSSION
BEE VISITATION ON GUAVA (PSIDIUM
GUAJAVA L.) — The guava crop was visited by all the three
species <strong>of</strong> honey<strong>bee</strong>s namely Apis dorsata, Apis cerana and
Apis florea. The relative abundance <strong>of</strong> honey<strong>bee</strong> visits to
flowers after spraying <strong>bee</strong> <strong>attractants</strong> was observed (Figs 1A,
B & C). The best mean foraging time was observed at 1000
hours (6.78 <strong>bee</strong>s/ 10 flowers/ 5 min ), followed by 1200 hours
(4.89 <strong>bee</strong>s/ 10 flowers/ 5 min) and 1400 hours (3.78 <strong>bee</strong>s / 10
flowers/ 5 min) The data and statistical analysis is given in
Table 1. Similar observations were reported by Kumar &
Lenin (1998). Bee scent @ 1.5 ml/l (15.67<strong>bee</strong>s/ 5 flowers/ 5
min.) was the most effective <strong>bee</strong> attractant in increasing <strong>bee</strong>
Table 1 — Foraging time and frequency <strong>of</strong> honey<strong>bee</strong>s on
guava
Hours Honey<strong>bee</strong>s/ 10 Flowers / 5 min
1 DAF 3 DAF 5 DAF Mean
0800 3.67 3.33 4.00 3.67
1000 7.00 6.67 6.67 6.78
1200 5.33 5.67 3.67 4.89
1400 3.67 4.33 3.33 3.78
1600 3.00 3.00 4.00 3.33
Mean 4.53 4.60 4.33 4.49
F-Test * * * -
SEm ± 0.447 0.471 0.517
CD at 1.408 1.484 1.629
5% level
*Significant at 5% Level, DAF-Days after Flowering

2012 <strong>Influence</strong> <strong>of</strong> <strong>bee</strong> <strong>attractants</strong> on pollination and yield parameters in Guava (Psidium guajava L.) — ANITA et al 43
A B C
D E F
G
H
Fig. 1 — A–H. Bee attractant treated plants. A. Apis dorsata. B. Apis cerana. C. Apis florae. D. Treatment fruit boost
at 0.75ml/L. E. Treatment with <strong>bee</strong> Scent at 1ml/L. F. Treatment with Bee Q at 15 gms/L. G. Bee colony kept in the plantation,
H. Fruit setting in open pollinated plant.

44 The International Journal <strong>of</strong> Plant Reproductive Biology
January, 4(1)
Table 2 — <strong>Influence</strong> <strong>of</strong> Bee <strong>attractants</strong> on Bee visitation on Guava ( Psidium guajava )
No. Treatment Bee VisitationMean Number <strong>of</strong> Bees /5 mins/ 5 Flowers
1 DBS 1 DAS 3 DAS 5 DAS
T1 BQ @ 10g/l 6.00 9.33 a 10.33 b 8.33 a b
T2 BQ @ 12.5g/l 4.67 13.00 c d e 14.33 c d 11.33 a b
T3 BQ @ 15g/l 4.00 11.67 b c d 13.33 b c 10.33 a b
T4 FB @ 0.5 ml/l 3.67 11.00 b c 12.33 b c 10.00 b
T5 FB @ 0.75ml/l 5.33 12.00 b c d 13.67 c 10.33 a b
T6 FB @ 1ml/l 5.00 12.00 b c d 12.33 b c 9.67 a b
T7 BS @ 1ml/l 4.67 13.00 c d e 13.67 c 11.33 a b
T8 BS @ 1.5ml/l 4.33 15.67 e 16.67 d 14.00 a b
T9 BS @ 2ml/l 5.00 14.00 d e 14.33 c d 12.00 a b
T10 OP (control) 4.67 7.00 a 7.00 a 6.33 a
F-Test NS * * *
SEm ± 0.658 0.837 0.856 0.714
CD at 5% level - 2.471 2.527 2.108
DBS- Day before Spray
DAS- Day after Spray
Table 3 — Effect <strong>of</strong> Bee Attractants on the Quantitative Yield parameters <strong>of</strong> Guava
Sl No Treatments Fruit Weight (gms) Fruit Volume (ml) Fruit Length (cm) Fruit Diameter (cm)
% % % %
Increase/ Increase/ Increase/ Increase/
Mean Decrease Mean Decrease Mean Decrease Mean Decrease
over OP over OP over OP over OP
1 T1 - BQ @ 10g/l 98.04 c 123.07 103.33 c 121.40 5.87 b 13.53 5.70 c d 8.15
2 T2 - BQ @ 12.5g/l 130.66 b c 197.27 130.00 d 178.55 6.67 c 29.01 6.70 f 27.13
3 T3 - BQ @ 15g/l 94.74 b c 115.56 93.33 b c 99.97 5.77 b 11.60 5.70 c d 8.15
4 T4 - FB @ 0.5ml/l 98.85 c 124.91 103.33 c 121.40 5.73 b 10.82 5.73 d 8.72
5 T5 - FB @ 0.75 ml/l 94.98 b c 116.10 96.67 b c 107.13 5.70 b 10.25 5.43 b c 3.03
6 T6 - FB @ 1ml/l 103.50 c 135.49 103.33 c 135.10 6.20 b c 19.92 6.03 b c 14.42
7 T7 - BS @ 1ml/l 101.00 c 129.80 101.67 c 117.84 6.17 b c 19.34 5.43 b c 3.03
8 T8 - BS @ 1.5ml/l 110.99 c 152.53 110.00 c 135.69 6.53 c 26.30 6.27 e 18.97
9 T9 - BS @ 2ml/l 85.39 b c 94.28 81.67 b 74.67 5.73 b 10.82 5.17 b -1.89
10 T10 - OP (Control) 43.95 a 0.00 46.67 a 0.00 5.17 a 0.00 5.27 b 0.00
11 T11 - Caged 61.32 a b 39.52 60.00 a 28.56 5.03 a -2.70 4.60 a -12.71
12 F - Test
13 SEm ± 0.182 0.125
14 CD at 5% level 0.53 0.37
SEm± - Standard Error, Means followed by the same letter in a column do not differ significantly by DMRT
Means followed by the same letter in a column do not differ significantly by DMRT.
st
visitation on the 1 day, followed by <strong>bee</strong> scent @ 2 ml/l
(14.00 <strong>bee</strong>s/ 5 flowers/ 5 min.). Bee Scent @ 1.5ml/l was
rd
equally effective on the 3 day (16.67<strong>bee</strong>s/ 5 flowers/ 5 min),
th
and 5 day (14.00 <strong>bee</strong>s/ 5 flowers/ 5 min). Bee Q @ 12.5g/l
was the next best attractant (14.33<strong>bee</strong>s/ 5 flowers/5 min) on
rd
the 3 day. The response between different treatments on
different days after spraying the <strong>bee</strong> <strong>attractants</strong> was found to
be statistically significant (Table 2).

2012 <strong>Influence</strong> <strong>of</strong> <strong>bee</strong> <strong>attractants</strong> on pollination and yield parameters in Guava (Psidium guajava L.) — ANITA et al 45
HARVEST PARAMETERS — The data and
statistical analysis on yield parameters given in Table-3
indicates the treatment wise response on the fruit weight,
fruit volume, fruit length and fruit diameter. The treatment <strong>of</strong>
Bee Q at the dosage <strong>of</strong> 12.5g/l was most effective at 5 percent
CD in increasing the fruit weight (130.66 g) followed by <strong>bee</strong>
scent at 1.5ml/l (110.99 gm), and fruit boost at 1.0 ml/l
(103.50 g). However, the least response was observed with
caged (61.32 gm) and open pollinated (43.95 g). Maximum
fruit volume was recorded with Bee Q at 12.5g/l (130.00
cm3) followed by <strong>bee</strong> scent at 1.5ml/l (110.00 cm3), and fruit
boost at 0.5ml/l (103.33 cm3). However, the least response
was observed with caged (60.00 cm3) and open pollinated
(46.67 cm3). Bee Q at 12.5g/l (6.67 cm) and <strong>bee</strong> scent at
1.5ml/l (6.53 cm) was equally effective at 5 percent CD in
increasing the fruit length compared to controls. The
maximum fruit diameter, was observed with Bee Q at a
dosage <strong>of</strong> 12.5g/l (6.70 cm) followed by <strong>bee</strong> scent at 1.5ml/l
(6.27 cm), and fruit boost at 1.0 ml/l (6.03 cm). The least
response was observed with caged (4.60 cm) and open
pollinated crop (5.27 cm). There was a marginal increase in
the total soluble sugars in Guava (6.83%) with crop sprayed
with Fruit Boost at 0.75ml/l compared to control. The
difference between treatments was statistically significant at
5% level (Table 4).
Table 4 — Effect <strong>of</strong> Bee Attractants on the Qualitative
Yield Parameters <strong>of</strong> Guava
Sl No Treatments Total Soluble Sugars (%)
Mean % Increase/
Decrease over OP
1 T1 - BQ @ 10g/l 4.91 b -7.35
2 T2 - BQ @ 12.5g/l 5.43 c 2.45
3 T3 - BQ @ 15g/l 5.43 d 2.45
4 T4 - FB @ 0.5ml/l 6.41 d 20.94
5 T5 - FB @ 0.75 ml/l 6.83 e 28.86
6 T6 - FB @ 1ml/l 4.81 a -9.24
7 T7 - BS @ 1ml/l 5.42 c 2.26
8 T8 - BS @ 1.5ml/l 5.43 c 2.45
9 T9 - BS @ 2ml/l 6.43 d 21.32
10 T10 - OP (Control) 5.3 c 0.00
11 T11 - Caged 6.41 d 20.94
12 F - Test
3 SEm ± 0.01
14 CD at 5% level 0.03
Means followed by the same letter in a column do not differ
significantly by DMRT
Our work shows a consistent benefit <strong>of</strong> honey<strong>bee</strong>
attractant in promoting pollination in Guava. There is an
evidence that Bee Scent at 1.5ml/L and 2ml/L increased total
rd
number <strong>of</strong> honey<strong>bee</strong> flower visitors on 3 day after spray
th
compared to control plot. It appears that on the 5 day after
spray <strong>of</strong> Bee Scent at 1.5ml/l and 2ml/l also shows numeric
significance to attract more <strong>bee</strong>s compared to control plot.
There was a significant increase in fruit weight with <strong>bee</strong> Q at
12.5g/l and <strong>bee</strong> scent at 1.5ml/l sprayed plots, which resulted
in 197.27 and 152.53 percent increase over control plot.
There was a marginal increase in fruit volume (ml) Bee Q at
12.5g/l and <strong>bee</strong> scent at 1.5ml/l sprayed plots, which
accounted for 178.55 and 135.69 percent increase over
control plot. Spraying <strong>of</strong> <strong>bee</strong> Q at 12.5g/l increased the Fruit
length to 6.67 cm and Fruit diameter to 6.70 cm compared to
controls. The total soluble sugars increased by 28.86 percent
with Fruit Boost at 0.75ml/l. In conclusion, it appears that
<strong>bee</strong> scent at 1.5ml/l increased honey<strong>bee</strong> visitation to improve
pollination performance over that in control plots. The <strong>bee</strong>
visitation on this plant translated into marginal increase <strong>of</strong>
yield parameters like increase in fruit weight, fruit volume,
fruit length and fruit diameter. It is because Bee scent is a
pheromone based liquid formulation which encourages
specific behavior <strong>of</strong> foraging in honey<strong>bee</strong>s. Fruit boost
mimics the honey<strong>bee</strong> queen mandibular pheromone (QMP).
Bee scent and fruit boost sprayed plots increased both the
forager number and inter-floral pollen movement. In case <strong>of</strong>
Bee-Q, since it is a food attractant rich in carbohydrate
content, it had a phagostimulatory effect, which attracted
more <strong>bee</strong>s to flowers that makes marginal increase <strong>of</strong> yield.
More broadly, this study suggests that the use <strong>of</strong> <strong>bee</strong>
<strong>attractants</strong> shows numeric promise as a management tool for
improving the efficiency and consistency <strong>of</strong> pollination and
productivity.
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