Purpose: We aim to clarify the physiological function of DNMT3.1 in extending longevity and energy allocation to reproduction under starved condition. In this study, we introduced a mutation into DNMT3.1 and analyzed the transcriptional changes, corresponded to phenotypic changes, of the mutant compared to wild type under starved condition. Methods: Whole body mRNA profiles of 12 days old daphnids from wild type (WT) and mutant (MT) cultured in nutrient rich (HF) and starved (LF) conditions were proceeded by using Illumina sequencing (provided by Novogene). Data analysis was performed by using CLC Genomics Workbench 12 (Qiagen) software. Results: In nutrient rich and starved conditions, numbers of differentially expressed genes were 220 and 2770 respectively, between wild type and mutant. Conclusions: Consistent with the DNMT3.1 mutant phenotypes, the starved condition led to larger difference of transcriptome between the mutant and wild type. This findind reveal how energy allocation is implemented by selective expression of a DNMT3 ortholog. Overall design: mRNA profile of 3 groups: starved wild type (WTLF), nutrient rich mutant (MTHF) and starved mutant (MTLF) were screened from 12 days old Daphnia magna in triplicates (total 9 samples). For comparision in nutrient rich and starved condition, 9 libraries of the above samples combined with 3 libraries of the triplicates from wild type in nutrient rich condition deposited in NCBI’s Gene Expression Omnibus (GEO) through the accession number: GSE150821.