ABSTRACT
Flies have been the most common problem encountered in husbandrymanagement either in big animals or poultry; and it has not been easy to solve.Disturbances caused by flies especially when the fly population is high do notdirectly affect the animals themselves, but they rather socially have effects on thebreeders and the people living in the areas -around the farm. The use ofchemical insecticide in controlling fly population around animal farms has beenminimized, and nowadays natural enemies of flies-are more commonly used.Research on the use of parasitoid insects in controlling flies has beencontinuously conducted in some countries. ln Indonesia, there have not beenmany studies done on the use of parasitoid insects particularly in animal farmingdespite the country?s big potential in fauna.The study on the use of parasitoid insects (Hymenoptera: Pteromalidae) incontrolling the population of filth flies in chicken farms was done by adopting datafrom research done earlier for 3 years (1996 - 1998). This research was apioneering work and was the only research ever on the application of parasitoidinsects in the field of animal husbandry conducted at three chicken farms in Bogor Regency. Observation on fluctuation of filth fly population and that ofparasitoid in relation to some macro climate variables recorded at the nearestweather station was done in the first year. In the following years, at one of thatchicken farm, an application of parasitoid by inundation of Spalangia endiusWalker (Hymenoptera: Pteromalidae) and monitoring of fluctuation of fly andparasitoid population were done with regard to micro climate variables in the henhouses measured by thermohygrograph.Correlation between monthly average population of fly and parasitoidduring dry and rainy seasons and that of some macro and micro climate variables was measured using correlation analysis for the identification of climatevariables that influenced the fluctuation of fly and parasitoid population the most.Natural phenomena and all the results of the data processing above,along with supply of secondary data derived- from existing references wasformulated into a system dynamic model. This is a model with a capability ofanalyzing dynamic behaviors of fly and parasitoid population that forming acomplex system which characterized by its 'relation to several factors (biotic anda biotic ones), related factors changing dynamically, as well as non linear relationand feedback mechanism in it. As far as macro climate is concerned, it has insignificant effects on thefluctuation of fly and parasitoid population despite a significant difference in themonthly total rainfall between the dry and the rainy seasons, because thechicken manure as flies breeding place in the pen system of egg layer hens areprotected, and thus the climate variables does not directly affect them. The correlation of monthly average population of fly puparia and progeny parasitoidindicated a high value (r = 0.914). lt showed the parasitoid characteristics beingpupal parasitoid and obligat toward fly puparia. The fluctuation of fly populationcorrelated only significantly with the humidity in the pen. Thus, the fluctuation offly population during the inundation period was not only infiuenced by parasitoidactivities but also by the fluctuation of monthly average humidity inside the henhouses.The construction of this dynamic- model was preceded by making a CausalLoop Diagram (CLD), producing three main subsystems namely the subsystemsof fiy and parasitoid which each fonning a positive feedback cycle (R=Reinforcing), and the subsystem of how the first two subsystems were relatedwhich forming a negative feedback cycle (B= Balancing).The Causal Loop Diagram described further how interaction mechanismbetween the flies and the parasitoid was as well as how it related to other variousfactors affecting that relation in a very complex system of chicken famiecosystem. Then, CLD was transformed into three models of Stock FlowDiagrams (SF D), the first of which was SFD picturing the dynamic of flypopulation and its parasitoid and its relation with factors of macro climate usingthe data from the research result ofthe first working paper. This was a naturalmodel for interaction between flies and parasiloid in a conditional ecosystem(Generic Model). The second model was the one for the use of parasitoid incontrolling population of flies with the application of parasitoid S. endiusinundation using the data from the research result of the second working paper (inundation Model). The last was a prediction model having some intervention toidentify the most important factors in the efforts of controlling the tlies by relyingon the role of parasitoid and a biotic factors. Due to limited data, the constructionof the model had to be carried out with strict assumptions.With the advantages of system dynamic model which were possible forbeing simulated and getting intervention, it was indicated that the increasingcapacity of parasitoid and pen humidity were important factors in the efforts ofcontrolling fly population in the ecosystem of chicken farm. Pen humidity wasbasically a representation of manure condition being a breeding place for bothflies and parasitoid, and was closely related with the structure and managementof the pen, either chicken food quality. Meanwhile, increasing capacity ofparasitoid could mean increasing number as well as potential ofparasitoid inattacking their host. in order to increase the parasltoid potential, efforts in habitatconservation supporting the survival of parasitoid have to be a primaryconsideration. |
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