HAYATI Journal of Biosciences March 2010 Available online at: Vol. 17 No. 1, p 38-42 http://journal.ipb.ac.id/index.php/hayati EISSN: 2086-4094 DOI: 10.4308/hjb.17.1.38 Diversity and Effectiveness of Insect Pollinators of Jatropha curcas L. (Euphorbiaceae) PUJI RIANTI∗, BAMBANG SURYOBROTO, TRI ATMOWIDI Department of Biology, Faculty of Mathematics and Natural Sciences, Bogor Agricultural University, Darmaga Campus, Bogor 16680, Indonesia Received November 30, 2009/Accepted February 22, 2010 Seed of Jatropha curcas (Euphorbiaceae) is currently established as the source for biofuel Therefore, it is important to understand the diversity insects that pollinated J. curcas inflorescence yellow flowers. We also aimed to study the pollination effects on fruit set on J. curcas. Scan sampling method were carried out to explore the insect pollinators diversity from 07.00 up to 17.00 h in every 15 minutes. Visiting frequency of pollinators insects were observed by using focal sampling. Those information together with flowering periods, flower nectar volumes, and environmental factors were used as the basic data to determine the effectiveness of insect pollination both in covered and uncovered of seed set plants. Results showed that nine species of insect pollinators were from three order (Hymenoptera, Lepidotera, and Diptera) pollinated J. curcas. Four species of Hymenoptera i.e. Prenolepis, Apis dorsata, Xylocopa confusa, and Apis cerana showed the highest abundances. The highest abundance and species richness of pollinators occurred at 08.00-10.15 and 15.00-17.15 h. Bees of X. confusa, A. cerana, and A. dorsata of Apidae are effective as insect pollinators in J. curcas plantations, due to high visited frequencies. The insect pollinators also increased fruits and seeds set of J. curcas in the uncovered experiment plants. Thereby, enhancement the three pollinator insects as part of crop management have to be considered by farmers. Key words: pollinator insects, diversity, visiting frequencies, fruit set, Jatropha curcas L. ___________________________________________________________________________ INTRODUCTION Jatropha curcas were visited by bees (Apis, Trigona and Ceratina), ants (Camponotus, Crematogaster, Nowadays we use many of edible sources (i.e. palm Solenopsis, and Pheidole), thrips (Scirothrips and thrips), oil, soybean, corn, etc) as biofuel resources. Jatropha and fly (Chrysomya) (Raju & Ezradanam 2002). In curcas L. showed the capability that also can be a resource Indramayu, West Java, J. curcas plantations were visited for that purposes. Other important useful of the plant are by bees, Apis cerana, Ceratina sp., and Hylaeus sp. used as traditional medicine, cattle woof resources, (Atmowidi et al. 2008). However, lack of experimental firewood, charcoal, paper pulp, fiberboard, and particles reports regarding to effectiveness of insect pollinators of board (Nuryani 2007), also can reduce CO2 pollution. J. curca. Here, we further analyzed the diversity, visiting Flower of J. curcas is a small, odorless, and yellow frequency, and effectiveness of insect pollinators in inflorescence with dichasial chyme pattern. It classified relation to seed set of J. curcas. as protandry or protogyny depends on type of sexes and amount of flower that first grown in one inflorescence. MATERIALS AND METHODS Flower transduction change protandry into protogyny at 40 + 2 oC. There are 100 flowers in one inflorescence with Study Sites. Study was conducted at J. curcas field ratio males and females are 29:1. Both sexes have five research plantation in Lulut Village, Kelapa Tunggal nectar glands produced nectar located at the base of District, West Java (+ 30,000 ha, 153 m asl; 06 030’ 09.7’’ S, flower. Male flower has ten stamens performed a circle 106 055’ 16.6" N) from March to October 2008. patterns. Pollen is yellow, globular, in aperture shape with Flower Phenology and Nectar Volume. The anatomies semitectate and perrucate axine. Diameters of pollen are of J. curcas flowers were observed to understand the between 81-89 µm, the number of pollen in lower and upper position of the nectar glands. Nectar volume from ten J. stamen are 220 and 435 grains, respectively. The female curcas plants were measured at 06.30, 08.30, 12.30, 14.30, flowers has three cell ovary that terminated by three styles. and 16.30 h. Nectar volume were measured by using During pollination, sepal and petal will protect the fruit microcapiller pipette (Dru USA by Drummond Sci. Co. development. Fruits will ripe after 40-50 days after No.4 (1-5 µl) (Stout et al. 2006). pollination follows with fruit color change from green to Insect Pollinators Diversity. Ten J. curcas plants were yellow. A fruit contain 3-4 black seed (Raju & Ezradanam selected and diversity of insect pollinators was observed 2002; Bhattacharya et al. 2005). every 15 minutes from 07.00 to 17.00 h by using scan _________________ ∗ sampling method. Several insect flower visitors were ∗Corresponding author. Phone/Fax: +62-251-8622833, E-mail: [email protected] collected for species identification purpose. Environment Vol. 17, 2010 Pollinators of Jatropha curcas 39 factors i.e. air humidity and temperature, light intensity, High nectar volume (4.09 and 3.85 µl for female and and wind velocity were measured in every insect males, respectively) occurred at 06.00-09.00 am and flowers observation. visited by six species of insect (total number 1,762 Insect Pollinators Visiting Frequency. Observations individuals). By afternoon, nectar volume decreased up of insect flower visiting frequency were conducted by to 0.42 and 0.37 µl for female and male flower. The scan sampling methods (Martin & Bateson 1993). The abundances of insects were positively correlated with observations included foraging rate (number of flowers/ number of flowers, while opposite result occurred with minute), flower handling time (seconds/flower), and plant nectar volume. handling time (seconds/plant) (Dafni 1992). Insect Pollinators Diversity. Nine orders of insect Measurement of Insect Pollinators Effectiveness. visitors in J. curcas plantations were Odonata, Orthoptera, Effectiveness of insect pollinators was measured by Mantodea, Homoptera, Thysanoptera, Coleoptera, number of fruits produced by plants that exposed to Hymenoptera, Lepidoptera, and Diptera. From these pollinators compared with fruits produced by covered observations we established nine species of insect plants. Before flowering, ten plants were covered by using pollinators (Table 1). Ants Prenolepis, always found in insect screen, while ten other plants were uncovered. After every observation, and has the highest abundance (1,772 30 days of fruiting period, the number of fruits per plant, individual) found at 07.00-07.15 h. Otherwise, three species fruits per bunches, fruit diameters, seeds per fruit, and of Apidae (X. confusa, A. cerana, and A. dorsata) have a seeds weight were counted. Seed viability (in percentage) high abundance in the morning and afternoon. Meanwhile, was measured based on germinated seeds in plastic bag butterflies, i.e. Junonia oritya, Graphium agamemnon, with three replications. Ariadne ariadne, and Eristalis tenax infrequently visited Data Analysis. Diversity of insect pollinators were the flower. The diversity of insect pollinators was higher analyzed based on Shannon diversity index (H’), Shannon in the morning and afternoon compare to noon (Table 2). evenness (E), Margalev species richness (d), and Sorensen The insects which found in the morning versus afternoon similarity (Cs), using Primer e-5 Programme. Analysis of was more similar (Cs = 77%) than both morning versus variance (ANOVA) and Tukey test at 95% level were noon and noon versus afternoon (Cs = 46%) (Figure 1). implemented for differences insect visiting behavior. T- The average of temperature during March until May 2008 test was also conducted to compare the number of fruit produced by plants that covered and uncovered by insect screen. Table 1. Number of species, individuals, and percentage of J. curcas insect pollinators diversity RESULTS Taxon Species Individuals Percentage (%) Hymenoptera Formicidae Anoplolepis 11 0.19 Flower Phenology and Nectar Volume. Flower of J. Prenolepis 4,409 75.16 curcas is small, odorless, yellow in color, and 4 mm in size. Apidae J. curcas was flowered daily during 06.00-08.00 h. The Xylocopinae Xylocopa confusa 523 8.92 flower bloom in 20 days, which male flowers were bloom Apinae Apis cerana 348 5.93 Apis dorsata 558 9.51 prior to the female and produce flowers daily until the Lepidoptera male buds shed. The peak of flowering periods occurred Papiolidae Graphium agamemnon 7 0.12 in day 12 to 15th and decreased until day 20th. Ratio of Nymphalidae male and female flowers was 33:1. There were five yellow Biblidinae Ariadne ariadne 5 0.08 Nymphalidae oval-shape glands in flower base producing nectar. Male Nymphalinae Junonia orithya 3 0.05 and female nectar volumes were 3.85 and 4.90 µl, Diptera respectively. The yellow color of flowers and the amounts Syrphidae Eristalis tenax 2 0.03 of nectar assumed the insect to visit. Total 9 5,866 100 Table 2. Total number of J. curcas insect pollinators in time blocks for 20 days observation Insect pollinators Time blocks (h) A B C D E F G H I N S 07.00-07.15 0 1,772 0 0 0 0 0 0 0 1,772 1 08.00-08.15 0 1,425 175 59 91 5 7 0 0 1,762 6 09.00-09.15 5 584 164 33 57 0 0 2 0 845 6 10.00-10.15 3 55 46 0 0 0 0 0 0 104 3 11.00-11.15 0 11 1 0 0 0 0 0 0 12 2 12.00-12.15 0 12 1 0 0 0 0 0 0 13 2 13.00-13.15 0 29 4 0 0 0 0 0 0 33 2 14.00-14.15 1 282 46 0 0 0 0 1 2 332 5 15.00-15.15 1 187 68 50 110 0 0 0 0 416 5 16.00-16.15 1 52 18 95 142 0 0 0 0 308 5 17.00-17.15 0 0 0 111 158 0 0 0 0 269 2 A: Anoplolepis, B: Prenolepis, C: X.