Abstract
While theory suggests that at conception the sex ratio should be balanced(1∶1),this can be variable across space and time in wild populations.Currently,studies of the environmental factors that regulate adult sex ratio(ASR)in species with different life history traits are scarce.Using capture-recapture over a year,we analyzed the influence of habitat type(forest and nonforest)and season(rainy and dry)on variation in ASR,male aggregation and the trajectory movement of 2 dung bee-tle species with different life history traits:Deltochilum mexicanum(a hornless roller species)and Dichotomius satanas(a tunneler species with horns on its head and thorax).We found opposite tendencies.The D.mexicanum population tends to be female-biased,but the population of D.sata-nas tends to be predominantly male,and observed values were not related to habitat type or sea-son.However,the 95％confidence intervals estimated were highly variable between seasons de-pending on habitat.On examining the monthly variation in ASR for both habitats,we found that it depends on the species.In addition,male aggregation differed between species depending on habitat type and season,and species movement patterns were closely related to their habitat prefe-rences.Based on our results,we argue that comparative population studies of species with differ-ent life history traits are necessary to understand the variation in demographic parameters as well as its ecological and evolutionary implications in the face of spatial and climatic environmental variation.
基金项目
Instituto de Ecología(project INECOL 20030-11189)
a PhD scholarship from the Mexican National Council for Science and Technology(CONACYT)(589280)
维普
万方数据