Sequencing analysis at the Beijing Genomics Institute (BGI; Shenzhen, China). RNA quality and quantity were verified using a NanoDrop 1000 spectrophotometer and an Agilent 2100 Bioanalyzer prior to further processing at BGI, and RNA integrity was confirmed with a number value of 8.6. The samples for transcriptome analysis were prepared using Illumina’s kit following manufacturer’s recommendations. Briefly, mRNA was purified from 44.4mg of total RNA using oligo (dT) magnetic beads. Fragmentation buffer was added for generation of short mRNA fragments. Taking these short fragments as templates, random hexamer-primer was used to synthesize the first-strand cDNA. The second-strand cDNA is synthesized using buffer, dNTPs, RNaseH and DNA polymerase I, respectively. Short fragments are purified with QiaQuick PCR extraction kit and resolved with EB buffer for end reparation and adding poly (A). After that, the short fragments were RE 640 connected with sequencing adapters. And, after the agarose gel electrophoresis, the suitable fragments were ��-Sitosterol ��-D-glucoside custom synthesis selected for the PCR amplification as templates. At last, the library could be sequenced using Illumina HiSeqTM 2000.called contigs. Then the reads were mapped back to contigs; with paired-end reads it was able to detect contigs from the same transcript as well as the distances between these contigs. Trinity connected the contigs, and gets sequences that cannot be extended on either end. Such sequences were defined as unigenes. When multiple samples from a same species were sequenced, unigenes from each sample’s assembly could be taken into further process of sequence splicing and redundancy removing with sequence clustering software to acquire non-redundant unigenes as long as possible.Analysis of Illumina Sequencing ResultsUnigene sequences were firstly aligned by BLASTX to databases like nr, Swiss-Prot, KEGG and COG (E-value ,0.00001), retrieving proteins with the highest sequence similarity with the given unigenes along with their protein functional annotations, the results about this were included in the folder annotation. With nr annotation, we used Blast2GO program to get GO annotation of unigenes. After getting GO annotation for every unigene [24], we used WEGO software to do GO functional classification for all unigenes and to understand the distribution of gene functions of the species from the macro level [25]. With the help of KEGG database, we could further study genes’ biological complex behaviors, and by KEGG annotation we could get pathway annotation for unigenes. When predicting the CDS, we first aligned unigenes to nr, then Swiss-Prot, then KEGG, and finally COG. Unigenes aligned to a higher priority database will not be aligned to lower priority database. The alignments end when all alignments were finished. Proteins with highest ranks in BLAST results were taken to decideDe novo Assembly of Sequencing Reads and Sequence ClusteringThe cDNA library was sequenced on the Illumina sequencing platform. Image deconvolution and quality value calculations were performed using the Illumina GA pipeline 1.3. The raw reads were cleaned by removing adaptor sequences, empty reads and low quality sequences (reads with unknown sequences `N’). De novo transcriptome assembly was carried out with short reads assembling program ?Trinity [21]. Trinity firstly 
combined reads with certain length of overlap to form longer fragments, which are Table 3. Putative genes involved in castes differentiation.Gene Annotation.Sequencing analysis at the Beijing Genomics Institute (BGI; Shenzhen, China). RNA quality and quantity were verified using a NanoDrop 1000 spectrophotometer and an Agilent 2100 Bioanalyzer prior to further processing at BGI, and RNA integrity was confirmed with a number value of 8.6. The samples for transcriptome analysis were prepared using Illumina’s kit following manufacturer’s recommendations. Briefly, mRNA was purified from 44.4mg of total RNA using oligo (dT) magnetic beads. Fragmentation buffer was added for generation of short mRNA fragments. Taking these short fragments as templates, random hexamer-primer was used to synthesize the first-strand cDNA. The second-strand cDNA is synthesized using buffer, dNTPs, RNaseH and DNA polymerase I, respectively. Short fragments are purified with QiaQuick PCR extraction kit and resolved with EB buffer for end reparation and adding poly (A). After that, the short fragments were connected with sequencing adapters. And, after the agarose gel electrophoresis, the suitable fragments were selected for the PCR amplification as templates. At last, the library could be sequenced using Illumina HiSeqTM 2000.called contigs. Then the reads were mapped back to contigs; with paired-end reads it was able to detect contigs from the same transcript as well as the distances between these contigs. Trinity connected the contigs, and gets sequences that cannot be extended on either end. Such sequences were defined as unigenes. When multiple samples from a same species were sequenced, unigenes from each sample’s assembly could be taken into further process of sequence splicing and redundancy removing with sequence clustering software to acquire non-redundant unigenes as long as possible.Analysis of Illumina Sequencing ResultsUnigene sequences were firstly aligned by BLASTX to databases like nr, Swiss-Prot, KEGG and COG (E-value ,0.00001), retrieving proteins with the highest sequence similarity with the given unigenes along with their protein functional annotations, the results about this were included in the folder annotation. With nr annotation, we used Blast2GO program to get GO annotation of unigenes. After getting GO annotation for every unigene [24], we used WEGO software to do GO functional classification for all unigenes and to understand the distribution of gene functions 
of the species from the macro level [25]. With the help of KEGG database, we could further study genes’ biological complex behaviors, and by KEGG annotation we could get pathway annotation for unigenes. When predicting the CDS, we first aligned unigenes to nr, then Swiss-Prot, then KEGG, and finally COG. Unigenes aligned to a higher priority database will not be aligned to lower priority database. The alignments end when all alignments were finished. Proteins with highest ranks in BLAST results were taken to decideDe novo Assembly of Sequencing Reads and Sequence ClusteringThe cDNA library was sequenced on the Illumina sequencing platform. Image deconvolution and quality value calculations were performed using the Illumina GA pipeline 1.3. The raw reads were cleaned by removing adaptor sequences, empty reads and low quality sequences (reads with unknown sequences `N’). De novo transcriptome assembly was carried out with short reads assembling program ?Trinity [21]. Trinity firstly combined reads with certain length of overlap to form longer fragments, which are Table 3. Putative genes involved in castes differentiation.Gene Annotation.
