| Seed dispersal is an important step of plant life history cycle,connecting plant reproduction and establishment.It is the key process of plants to occupy the new habitat,while the seed dispersers play an important role in seed location and fate of seeds.Myrmecochore involves plants bearings elaiosomes,which attract to the ant.When ants find the seed which bears elaisome,then select the favorite ones,transport to nest or not,abandon the diaspore after eating up the elaiosomes.During transport,seed traits,the ant species and behavior,environmental factors,which effect seed dispersal distance and removal rates,seed germination and establishment,thus myrmecochory impact plant community dynamics,i.e.succession,regeneration and fluctuation.Corydalis acuminata Franch.and Corydalis sheareri S.Moore,Attached to Papaveraceae,are annual herbs.C.acuminata Franch.distributed in the western Hubei alpine moist mountain habitats,as endemic species on the western of Hubei,but C.sheareri S.Moore spreads widely in china.Recently,few studies on the myrmecochory of Corydalis DC.This paper studies the ballistic and myrmecochory of Corydalis acuminata Franch.and compare the seed dispersal of Corydalis acuminata Franch.and Corydalis sheareri S.Moore by ants,investigate the ant species and its behavior,find out how rain and drought effect on seed dispersal.The purpose of this study was to evaluate the mutualism of myrmecochorous and ants.The main findings are as follows:1.We found out five ants species that remove seeds of C.Acuminata Franchet,which were Paratrechina vividula Nylander,Myrmica sp.,Lasius alienus Foerster,Paratrechinayerburyi Forel and Pheidole sp.;For C.sheareri S.Moore,there were four ants species to remove its seeds,which were Lasius alienus Foerster,Formica fusca Linnaeus,Pachycondyla javana Mayr and Paratrechina vividula Nylander,there were two ants disperse seeds both of those Corydalis.The difference of ants species and its abundance,the size,foraging behavior and competitiveness of ants may effect the affect the seed dispersal distance,especially,the seed dispersal distance by ants increased with the size of ant body.The removal rates of intact seed of C.Acuminata Franchet is more than that of seed without elaisome,but remarkable difference not exists(F= 3.243,p>0.05),while the removal rate of intact seed of C.sheareri S.Moore is significantly higher than seeds without elaisome(F = 20.503,p<0.05),the result suggested that elaisome was the attractive part of diaspore,and removal of elaisome reduce seed removal rate by ants.In C.acuminata Franchet ballistic dispersal,the range of dispersal distance was 8-202 cm,the mean distance was 59.9 ± 40.9 cm(mean ± SE,n = 483),In ant dispersal,the range of dispersal distance was 3～224 cm in C.Acuminata Franchet,and 0.02～1.50 cm in C.sheareri S.Moore,the mean dispersal distance was 40.9 ± 39.2 cm(n = 50)in C.Sheareri S.Moore,but only 27.9 ± 26.4 cm(n = 77)in C.Acuminata Franchet.The results suggest that C.sheareri S.Moore is more dependent on ant dispersal while C.Acuminata Franchet is more dependent on ballistic dispersal,the relative importance of myrmecochory were different in different species,which may be related to the size of elaisome and the way of per-dispersal,the seed dispersal mechanism and the variety of ants effect the distribution and recruitment of individual.2.Compared to the seed remove rates of the considerable body size dispersers Paratrechina vividula Nylander and Lasius alienus Foerster,slow-moving ants Paratrechina vividula Nylander cooperative foraging seed,but Lasius alienus Foerster search and remove seeds alone.Whenever 2011 or 2012,The seed removal rates of Paratrechina vividula Nylander significantly higher than Lasius alienus Foerster(F =7.194,P = 0.012,P<0.05;F=49.766,P=0.000,P<0.01),and be unaffected by time.3.It was found that seed removal rates first decrease then increase with the duration of hydration.In case of C.Acuminata Franchet,the 6h-hydration seeds was removed more often than the others(33.3±3.3,mean ± SE,n = 3)per 30 min,and then 12h-hydration seed was the minimum(1.0±0.7),even less than the fresh seed(8.0 ± 1.3).For C.shearri S.Moore,the 6h-hydration seeds was also the maximum(34.0±42.5)per 20 min,and then 24h-hydration seed was the minimum(15.3 ± 12.9),and less than the fresh seed(31.3±4.04).Nevertheless,the removed rate of hydration exists significant difference in C.acuminata Franchet(p<0.05),but not C.shearri S.Moore(p>0.05);Seed removed rates decreased with seed desiccation,3h-desiccation and 6h-desiccation seed have no notable difference with fresh seed,the decline in the removal rates of C.acuminata Franchet afterl2h desiccation,C shearri S.Moore after 24h,and significant lower than fresh seed.The results suggest that C.sheareri S.Moore is more dependent on ant dispersal while C.Acuminata Franchet is more dependent on ballistic dispersal,the relative importance of myrmecochory were different in different species,which may be related to the size of elaisome and the way of per-dispersal,the seed dispersal mechanism and the variety of ants effect the distribution and recruitment of individual;different species of ants due to the different capabilities of raising companions and behavior in removal seed,suggesting the mutualism ants between plants influenced by ants species;different species of ants due to the different capabilities of raising companions and behavior in removal seed,suggesting the mutualism ants between plants influenced by ants species;the duration of rain and drought impact on the contribution of seed dispersal,because it indirectly alters the probability of seed whether dispersal by ants.Thus reveals that the contribution of myrmecochory to seed dispersal impact by plant seeds,ant types and its behavior,and environmental factors. |
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