BioSample

Protocols: L. sclopetarius adult female spiders were collected in the wild in a small habitat in Uppsala, Sweden. Taxonomic identity of the spider was verified by the Museum of Natural History, Stockholm, Sweden. The spiders were kept in big containers that allowed them to spin webs. They were fed with meal worms or Drosophila flies weekly and watered daily. The spiders were anesthetized using dry ice before they were dissected on ice. After making an incision at the pedicel, the abdomen was gently pinned to a wax plate placed under a Zeiss Stemi 305 stereo microscope, and the exoskeleton was carefully removed with micro scissors to visualize the silk glands. Phosphate buffered saline (PBS, pH 7.4) was used to wash off the excess non-silk tissue. With the help of micro tweezers, silk glands (major ampullate glands, minor ampullate glands, flagelliform glands, aggregate glands) were isolated separately by holding their ducts. The aciniform and piriform glands from these five spiders were extracted as a single sample due to difficulties in separating them owing to their small sizes. The major ampullate glands from six additional individuals were cut into three parts: tail, sac and duct and used for RNA extraction. In another preparation, after removing the exoskeleton the soft tissue from the whole abdomen was scraped out and used for extracting RNA. The RNA from head was extracted similarly after removing the legs and the thick exoskeleton. Five replicates were collected for each sample type and RNA was extracted from each replicate separately. RNA samples were extracted using RNeasy Plus Mini kit (QiaGen) by following the manufacturer's protocol. The integrity of the samples was estimated using Tapestation (Agilent Technologies). The transcriptome libraries were generated using Illumina TruSeq Stranded mRNA kit following manufacturer's protocol (X).