Studies On The Reproductive Development And Experimental Population Of Coccinula Quatuordecimpustulata (Linnaeus)

In this paper, we use Coccinula quatuordecimpustulata, the natural enemy of Aphisgylcnies, as the experiment insect to study the feeding habits, developmental rate rearingon different aphids, reproduction under different conditions, life table, intraspecific andinterspecific competitions. Here are the results:1. The1st-4th instar larvae and adult of C. quatuordecimpustulata were fed on13species of aphids respectively, from the records of day maximum predation, it could showthat C. quatuordecimpustulata could prey on all aphids for test. However, the predationwas significant differences among these13species of aphids. The food preference of C.quatuordecimpustulata was identified by the biomass of the daily predation because of thedifferent sizes among all aphids for test.2. Fed C. quatuordecimpustulata with Aphis glycines, Acyrthosiphon pisum andChaitophrus populetii. The result shown all pupas could eclosion normally. However,developmental durations of C. quatuordecimpustulata fed on A. glycines and A. pisumwere shorter than fed on C. populetii.3. Fed C. quatuordecimpustulata with A. glycines enough in22,24,26,28and30℃.The results indicated that the fecundity was significant differences among them. Theoviposition period of C. quatuordecimpustulata was the longest when it was in28℃, thetotal oviposition rate per female was largest and the fecundity was the most powerful at thesame time. The same experiment began with different photoperiods (L:D)16:8,14:10,12:12,10:14and8:16. The fecundity was significant differences as well. Thepre-oviposition period of C. quaruordecimpustulata was the shortest, the ovipositionperiod was the longest, the total oviposition rate per female was largest and the fecunditywas the most powerful. The results demonstrated that the most suitable temperature andphotoperiod were28℃and14h.4. The age-specific life table and the reproductive-characteristics life table ofC.quaruordecimpustulata were established. We obtained that the intrinsic rate of naturalincrease was0.055. The mortality of C.quaruordecimpustulata in different stages weredefined. The mortality in egg stage was the highest, it was49.0%. The population quantity after a generation was25times the original population quantity. The populationquantity after one day was1.057times the day before.5. The conditions and process of intraspecific competiton was defined. Density was asignificant factor to cause intraspecific competiton. The intraspecific competiton wouldslow down with the decreased density. The intraspecific competiton was tiny when thedensity was2.3insect per cubic decimeter. C. quaruordecimpustulata was slightlyinferiority in competition with A. politus and the two species could form a balancesituation, both coexist in one system.