Pelita PerkebunanAbundance 32(2) 2016, of pollinator 91—100 insect (Forcipomyia spp .) of cocoa underISSN: some shade0215-0212 trees / e-ISSN: 2406-9574 Abundance of Pollinator Insect (Forcipomyia spp .) of Cocoa Under Some Shade Trees Fakhrusy Zakariyya,1*) Endang Sulistyowati1), and Dwi Suci Rahayu1) 1)Indonesian Coffee and Cocoa Research Institute, Jl. PB. Sudirman 90 Jember, Indonesia, dan 68118 *)Corresponding author: [email protected] Received: 15 March 2016 / accepted: 23 June 2016 Abstract Cocoa production is affected by cocoa flowering and fruiting. The factor affects fruit seeting is pollinator agent such as Forcipomyia spp. Until now, information concerning population dynamics of Forcipomyia in some models of cocoa shading trees remains limited. This research was studied to observe the population dynamics of Forcipomyia spp. in some models of cocoa shading trees, namely lamtoro (Leucaena sp.), krete (Cassia surithensis) and areca nut (Areca catechu) in two main season of rainy and dry seasons. The research was conducted in Kaliwining research station of Indonesian Coffee and Cocoa Research Institute (ICCRI), Jember, by surveying the existing cocoa under different types of shading trees as mentioned above. The insects were observed using modified sticky trap method, whilst micro climate condition was also observed. The highest population was in January (rainy season) under Leucaena spp. shade tress and the lowest population was in October under all type of the shading trees. There was no relationship between microclimate condition under cocoa trees (temperature, RH and light intensity) and Forcipomyia spp. population (r = 0.08 and 0.04). Keywords: cocoa, shades tree, population dynamics, Forcipomyia spp. INTRODUCTION are less than the optimal condition, including farming management with relatively low Cocoa is one of Indonesian main commodi- input factors, such as limited availability of ties which play an important role in improving fertilizers and water (Prawoto et al., 2006). national economy. Currently, Indonesia is The shading plants for cocoa have some as the third largest cocoa exporter country roles in several aspects, such as transmitted after Ivory Coast and Ghana. However, sunlight, temperature air humidity, nutrient average national cocoa productivity was only availability and soil organic matter that may about 0.47 tons per hectare (Wahyudi & affect physiological processes of flowering Misnawi, 2015). In addition, opportunity to and habitat of growing insect pollinators increase cocoa production is still possible, associated with the formation of the fruits and also what strategies should be done in (Prawoto, 2013; Evizal et al.,.2012). More- order to increase the cocoa production as over, number of cocoa flower may reach well as the constraints that can be encoun- 6000 to 10000 buds per year, but only 2.5% tered. Using of shade trees in cocoa farm of those flowers are pollinated (Kaufman, may solve the problem. 1975); thus, the presence of insect pollinators Cocoa cultivation requires shades, is very essential. In some cocoa production especially when the environmental conditions areas, common shading plants which are PELITA PERKEBUNAN, Volume 32, Number 2, August 2016 Edition 91 Zakariyya et al. used in the cocoa plantations are namely in the microclimate, such as temperature lamtoro (Leucaena spp.), gamal (Gliricidia and relative humidity in an area does not sepium), coconut (Cocos nucifera), and areca affect significantly on the population of nut (Areca catechu) (Prawoto, 2008). Forcipomyia spp. Existence of shade trees serves as buffer With the difference in shade trees, it is and reducing the risk of extreme fluctuations still uncertain that the dynamic population of environment in the plantation production of Forcipomyia spp. in certain season and area due to climate change and the seasonal microclimatic condition is also different. condition. The shade trees keep the environ- However, cocoa flower pollination by in- ment in the farm remained stable (Prawoto, sect pollinators is external factor that influ- 2008). Moreover, it is able to keep the life ences the formation of pods in cocoa cycle of the insect pollinators living optimally. (Winder, 1978; Stephenson, 1981; Bos et Any information related to the effects of the al., 2007; Omolaja et al., 2009). Research shade trees to the insect pollinators have been on cocoa insect pollinators, especially in discussed by Boreux et al. (2013) with the Indonesia, has been widely studied in 1950’s subject was that coffee plant which shows and 1980’s, but it is still necessary to ana- that the density of the protecting effect on lyze current information related to this sub- pollinators due to litter and micro-climatic ject. The purpose of this study was to as- conditions ultimately affects the crop production. sess the abundance of insect pollinators Fruiting set of the coffee berry can be increased Forcipomyia spp. in rainy season and dry more than 50% since it is pollinated by the season on cocoa under three shade trees insect pollinators (Ngo et al., 2011; Klein namely lamtoro (Leucaena spp.), krete et al., 2003). Some researchers also noted (Cassia surattensis), and areca nut (Areca that the number of fruit formation in plants catecu). determines the success of the production (Stephenson, 1981; Pias & Guitian, 2006). MATERIALS AND METHODS In cocoa, insect pollinators become the major factor given the structure of cocoa This research was conducted in Kaliwining, flower pollination has a very complicated Experimental Station of Indonesian Coffee structure (Adjaloo & Oduro, 2013). There and Cocoa Research Institute (ICCRI), is only a small possibility that pollination occurs Jember, East Java, with rainfall type of D by the assistance of wind. Interest of insect (Schmidt & Ferguson) with relatively flat pollinator which affects the pollination of topography at altitude 45 m asl. The study cocoa has been reviewed by Kaufman was conducted during dry season in August (1974), who found that there were some to November 2015, and rainy season within insect pollinators of specific genus of December 2015 to February 2016. Observations Forcipomyia (Dipteral: Ceratopogoniidae) were made with the survey method on some which were dominant contributing to models of shade trees of cocoa including natural pollination for cocoa. Population of lamtoro (Leucaena spp), krete (Cassia Forcipomyia spp. also depends on climatic surattensis), and areca nut (Areca catechu). conditions of one region and also season in Cocoa plants used were bulk cocoa one particular area (Adjaloo & Oduro, 2013). (Theobroma cacao L.) clones of Sulawesi 1 In addition, Ibrahim & Hussein (1987) that was 6 years old in an area of 0.5 ha with however explained that the difference the number of 500 plants. 92 PELITA PERKEBUNAN, Volume 32, Number 2, August 2016 Edition Abundance of pollinator insect (Forcipomyia spp .) of cocoa under some shade trees Insects were trapped by using modified from the experimental plantation of sticky traps (Sulistyowati, 1986; Thompson Kaliwining are in the form of rainfall and et al., 2014) by modifying the color of the the intensity of radiation taken at the weather trap with a colored translucent plastic, and station during the observation period. the insects were observed and monitored Statistical analysis of the parameters of the every two weeks. Sticky traps can be used insect population every month was conducted for the activity of flying insects, especially by using analysis of variance with a confidence from families Ceratopogoniidae for having level of 95%. If there is a real effect of the hairy body so as to facilitate them being treatment followed by Tukey’s test for further trapped. Sticky traps were placed between result (a = 5%) (Gomez & Gomez, 1984). the rows (aisles) of cocoa trees at a height of 100 cm above the ground. There were ten traps (n = 10) which were placed randomly RESULTS AND DISCUSSION with the spread radius of 120 to 150 cm The distribution of rainfall in the ex- of cocoa under the shade trees. Sticky traps perimental plantation of Kaliwining can be placed at 6 a.m. until 5 p.m. during peak seen in Table 1. The El Nino phenomenon insect activity (Adjalo & Oduro, 2013). in 2015 led to a dry months until October Sticky traps are then identified in the 2015. In 2015, it appeared that the dry Laboratory of Plant Protection, ICCRI in months occurred in September, October, Jember East Java using a magnifying glass while the early November and December and a dissecting microscope at a magnifi- 2015 was shifting period in rainfall changes. cation of 40x. Population was calculated by Rainfall has increased dramatically as much taking and observing one by one of the insect as 64.9 to 73.7% in January and February being stuck to each sticky trap and confirmed 2016 with the rainfall of 340 and 453.7 mm. in accordance with the taxonomical morphology The condition of light intensity in experimental of Forcipomyia spp. based on Scudder & plantation of Kaliwining showed that in Cannings (2006). September-November 2015 reached to Microclimate conditions of temperature 93–94%, whereas within December to (OC) and relative humidity (%) were also February, the light intensity was 64–82%. measured by using a manual-type thermo- Devoto et al. (2009) reported that the hygrometer A600FC. While the light intensity distribution and precipitation gradients may of the shade trees was measured using affect some kinds of life of the insect a digital luxmeter type. Data related to pollinators on agroforestry ecosystems in microclimate were obtained every two the southern part of South America. Additionally, weeks during the study. The data were then Sulistyowati (1986) reported that Forcipomyia summed to obtain the average point, and prefers calm and clear cloudy weather. standard deviations were calculated. Data Table 1. Rainfall distribution and light intensity of Kaliwining Experimental Station during observation Month Rainfall, mm Days light, % September 0.0 94.6 October 5.5 92.1 November 120.7 93.5 December 119.3 68.9 January 340.0 82.9 February 453.7 64.7 PELITA PERKEBUNAN, Volume 32, Number 2, August 2016 Edition 93 Zakariyya et al.