| The rare butterfly,Luehdorfia chinensis Leech,is endemic to China as a class second nationally protected animal and IUCN red list species.It is mainly distributed in the Qinling Mountains and in the middle and lower reaches of the Yangtze River.The larvae feed on Asarum sieboldii and Asarum forbesii of Aristolotheaceae,and the butterfly occurrence is often limited by hostplants distribution and resource patch size.The butterfly population is usually a typical metapopulation in occurrence and distribution.The dispersal ability of adults determines individual communication and genetic material communication between small populations or sink populations.At present,there are few studies on the adult dispersal and metapopulation dynamics of L.chinensis,and the phenophase asynchrony of butterflies and their hostplants under the pressure of climate change due to physiological development changes or adjustments.In the early stage,the larvae fed in clusters,and after the 3rd instar,the larvae dispersed with the increase of feeding amount.Its hostplants are often scattered in wild and the distance among patches is usually large,which makes the larvae often suffer from starvation stress during the scattered feeding process.However,it is not clear how this stress affects the growth and development of butterfly larvae and population size.In addition,the protection of butterfly habitat needs to first understand the needs of its habitat,and the impact of habitat fragmentation or available resources on the occurrence of butterfly population.Therefore,it is urgent to carry out special investigation and case study on the biological characteristics,field population status and habitat demand characteristics of the only surviving Taohongling population of L.chinensis in Jiangxi.Based on the previous knowledge,there are two small populations(Maoyingwo and Taohongshang)of L.chinensis in Taohongling,and the distance between the two as the straight line is 2km.Therefore,this study takes the Taohongling population as a case study.Using Age-Stage,Two-Sex Life Table Analysis method,the L.chinensis Taohongling population in the process of larval growth and development caused by the spread of hunger stress on individual growth and development and the influence of population size,analyze the growth of the population(such as development,adult traits,etc.)and population reproductive size(such as fertility,intrinsic growth rate population parameters),reveal the hunger stress on the individual and the population itself;The habitat of butterfly in the occupied and non-occupied areas was monitored by sample method,and the pupation habitat of mature larvae was selected by double selection and multi-selection experiments to explore the preference of the butterfly to the habitat(Selection of pupation sites).The main results and conclusions are as follows:(1)The population size of L.chinensis was small in Taohongling,the structure of metapopulation was incomplete,and the current status was not optimistic.The L.chinensis occurs one generation a year,and the pupal stage is too long(>300 days);Its annual life history is synchronized with the development phenology of the host plant A.forbesii.For example,the butterfly begins to emerge after the first leaf stage,and the butterfly eggs hatch after the leaf spread stage.The larval stage before the plant enters the dormant stage already ended(Before the beginning of May),and the pupal stage begins.Marker-recapture records showed that the butterfly population in Taohongling was significantly small(only 31 individuals adult were recorded in 2021 and 2022 years),and the metapopulation was basically isolated in MYW and THS(no individual communication between small populations).What ’s worse,the wild population was male-biased(2021 years male : female = 1.82 :1;2022 years male : female = 13.5 : 1),and the situation has an aggravating trend,which is not conducive to population reproduction.The data show that the butterfly population shows a downward trend in 3 years.This may also be related to the decline in the early increased deaths of butterflies.For example,the survey found that the early survival curve of butterflies in 2019 years was Deevey-II type,but it turned to Deevey-III type in 2021 and 2022 years.In addition,the change of butterfly population may also be affected by early spring climate shocks.For example,the emergence date of butterfly in 2022 years was delayed compared with that in 2019 years and 2021 years,and the peak days of adult activity were also reduced compared with that in 2019 years and 2021 years.However,the daily activity rhythm of adults did not change,and the peak was around 10 : 20 in the morning,and the male butterflies were earlier than the female butterflies.The population size was predicted based on the Marker-recapture data.It was found that the Schnabel method was better than the Lincoin index method,and the predicted population size was consistent with the egg counting method.For the L.chinensis,the egg counting method predicts the female butterfly number is closer to the reality.(2)Moderate starvation experiments in instar larvae showed that the earlier the starvation stress appeared,the more the individual fitness of the butterfly decreased.The moderate starvation stress in the field was simulated by 3days of starvation.The results showed that the starved individuals were affected to varying degrees during starvation(head shell width,weight,length and other traits changed significantly).However,the 3rd instar starvation experiment(3SE)was most severely stressed during starvation,and almost zero growth was observed during starvation(such as no change in body weight instantaneous growth rate IGR),while the IGR of 4th instar(4SE)and 5th instar(5SE)starvation individuals was still increasing during starvation.Moderate starvation had no significant effect on the survival rate,pupation rate and pupal weight of butterflies,but there was a significant fitness cost in the individual fecundity of female butterflies,which significantly decreased their fecundity(decreased eggs carried and fecundity).(3)Moderate starvation reduced the fecundity of the butterfly population,affected population growth and made it show a downward trend.Moderate starvation for three days did not affect the survival of butterfly larvae,and no dead individuals were observed.But its adverse effects appeared in the pupal stage,resulting in shortened pupal development time and increased mortality.Moreover,after starvation stress,the number of eggs carried and number of eggs laid per female decreased,and the 3rd instar was more affected than the 4th and 5th instars,and the fecundity of the butterfly population decreased significantly.Age-Stage,Two-Sex Life Table analysis showed,After moderate starvation,the population Reproduction rate,Net reproductive rate,Fecundity,Intrinsic rate of increase,net growth rate and Total fecundity decreased significantly compared with the check.Using the moderately hungry contemporary population to predict the population growth trend in the next two years,it was also found that the population growth rate of the hungry group decreased from 1.7 to about 1.3 in the next two years,showing a significant downward trend,while the control group population increased significantly,and the population growth rate can increase from 2.5 to about 3.5 in next two years.(4)In the Taohongling,the habitat of L.chinensis was specialized in the wild,mostly shrub and grass habitats,and preferred areas with higher environmental humidity throughout the year(such as the northern slope of MYW and THS),the habitat needs of butterflies were similar to those of their host A.forbesii.The survey results show that butterfly and A.forbesii occupied area habitat herb coverage,shrub coverage,herb number and litter thickness were higher,showing a positive correlation.Butterfly occurrence was also positively associated with the number of host and honey source.However,it was negatively associated with shrub height,arbor coverage,and arbor height.The multi-choice and dual-choice experiments showed that mature larvae had different choices for different pupation sites or substrates.The number of individuals selected by litter is the most,followed by grasses and stones,and only a few individuals chose to pupate on bare soil.Under semi-natural conditions,the survival rates of pupae in multi-choice and dual-choice cages were 0.07 and 0.13,respectively.In particular,the survival rate of pupa is of fallen leaves is lower than that of shrubs,grass and stones.The pupation height of larvae was concentrated at 4-6cm.The height of pupation is mainly concentrated in4-6cm.The distance between the pupation position and the release center is 25-55 cm in multi-choice.The dual-choice cage is concentrated in 15-20 cm.The quadrat survey showed that the temperature,relative humidity and light conditions in the occupied and non-occupied areas were significantly different in some stages of the pupal stage and some developmental stages of A.forbesii.For example,there were significant differences in temperature,humidity and light conditions during the first development period of pupae.In the secondary development period and the secondary diapause period,the relative humidity and light were significantly different;the relative humidity was also significantly different in the pre-eclosion stage of butterfly.However,for the development of A.forbesii,the relative humidity of the two areas was significantly different at the bud swelling stage,initial leaf stage and dormant period,while the light conditions were significantly different at the dormant period.However,there is no significant difference in temperature conditions between the two regions. |
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