| Phalera flavescens (Bremer et Grey)(Lepidoptera:Notodontidae:Phalerinae) was one of the most serious defoliators which was harmful for the plantation of Betula alnoides. Aimed at having a good knowledge of the morphological characteristic, living behavior, occurrence regularity and population dynamics of Phalera flavescens then having an effective control on it, the test indoor and field survey were systematically carried out to study on its biological and ecological characteristics in the research. The results were as follows:1. The morphological characteristic of the Phalera flavescens’s female and male adults were so different.The body of female adults were18-28mm in length and the male ones were16-21mm.The antenna of the female adults were filiform while the male ones were double pectinate in the3/4from frontal region to the tail-end, the rest1/4parts were filiform. The scanning electron microscope was used to observe the external morphology of antenna.8kinds of the antennal sensilla were found, including sensilla trichodea, sensilla basiconica, sensilla styloconica, sensilla chaetica, sensilla falcate, Bohm bristles, sensilla squamiformia, sensilla gemmiformia. The larvae had5or6instars. The phenomenon of instars differentiation happened to the larvae population, too. The larvae of fifth or sixth instar had a very long body length which could be57mm. The female and male pupae were different from each other in the body size, too. The female pupae were23.82±1.508mm in the average length, and the male ones were21.24±1.598mm. The shapes of the eggs were oblate spherical or circular with the diameter about0.8～1.0mm.2. Phalera flavescens occurred1or2generations within1year in Laoshan Forest Farm, Baise City, Guangxi, and it was a complete metamorphosis insect. The population happened with the partial generation phenomenon. It over-wintered with the pupae in the soil.The emergence period of the overwintering adults was in July or August, and it would last for about one month. The larvae happened in August or September. The emergence period of Phalera flavescens might be different in vary year due to the environment conditions.3. The larvae had their own selective feeding behaviour. They’d like to have the leaves of the Betula alnoides more than the Eriobotrya japonica and Castanea mollissima ones. They didn’t eat the leaves of Eucalyptus sp. any more. The feeding amount of the mature and old leaves of the Betula alnoides had no obvious difference because the larvae liked to eat them in the same level. The larvae didn’t like to eat the young leaves. Every instar of the larvae’s feeding amount varied from each other, such as the first to the third instars were very small, while after the forth instar the larvae’s feeding amount could get bigger and bigger. When it came to the fifth or sixth instar, the larvae could eat42.82～47.90cm2/head in one day and then they could cause serious harm to the forest.4. The emergence of the adults happened more concentrated in night time (19:00～23:59), which accounted the total number of emergence for43.53%. The peak time of emergence period lasted for about10d which appeared in the late July. There was no significant difference between the female and male adults in the emergence date and time. The sex ratio of female and male adults was1:1.08, that was close to1:1.5. The larvae of Phalera flavescens mainly distributed at0-149.9cm, the subsection of branches from the tail-end to the trunk, accounted the total larvae’s number for96.92%. The analysis of variance showed that the larvae’s number in every subsection of branches had a significant difference. The pupae mainly distributed in the0-150cm semidiameter to the base of the bole in horizontal, and0～10cm depth of the soil layer in the vertical. The closer horizontal distance to the base of sample tree’s bole or the closer depth from the surface layer of the soil regions they were, the more quantities of pupae they had, on the contrary the fewer they had. The distribution of the pupae in the horizontal and vertical interval range in the soil had a significant difference.The spatial distribution of larvae and pupae were both aggregated, and the basic component was individual colony. The behavior of Phalera flavescens, or both the effect of environmental heterogeneity and Phalera flavescens’s behavior, even the environment factors influence could be its aggregation reasons.6. The relationship between the emergence of Phalera flavescens and the depth of pupae in the soil was that:the number of emergence in the1～3cm depth in the soil was closely to the contrapositive3-3.5cm ones, the emergence rate was55.56%～86.11%, while the number of emergence in5-6cm depth in the soil was less than the1～4cm ones, the emergence rate was only30.56%-44.44%.7. The larvae of Phalera flavescens could eat the leaves of Betula alnoides both in the light and dark conditions. There was no significant difference in the feeding amount. The larvae could eat the leaves of the Betula alnoides normally at the temperature of18℃～30℃and survival well. But when the low temperature was sustained at10℃～15℃or the high temperature was sustained at35℃～40℃, the larvae could not be fed, and the survival time was only1～2d.8. The larva distributed in the forest fringe more than in the interior forest, so the forest fringe was more harmed by the larvae than the interior forest. The larvae always ate up the forest fringe then turned to the interior forest. This might be related to the ventilation, moisture content, illumination or other factors.The innovative points of this paper were as follows:firstly it studied the characteristic of every stage, the larvae’s feeding characteristic, the spatial distribution of the larvae and pupae of Betula alnoides’s pest Phalera flavescens more systematic, secondly it discussed the relationship between the occurring of Phalera flavescens and the environment factors preliminarily, and thirdly it provided the theoretical basis for the scientific control of the Phalera flavescens. |
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