Fig 6 shows mean spidroin expression (2-ΔΔCT) values across treatments for each species. Interestingly, the across treatment expression patterns differed significantly among the five species (Wilk’s λ = 0.011,d.f. = 5,10, P <0.001). We found that A. keyserlingi upregulated the expression of MaSp1a within their MA gland when protein deprived (F1,28 = 13.911, p < 0.001). E. transmarina on the other hand downregulated the MaSp1a expression within their MA gland when protein deprived (F1,28 = 42.171, p < 0.001), but upregulated MaSp1b (F1,28 = 8.135, p = 0.005). L. hasselti upregulated their MaSp1a (F1,28 = 12.308, p < 0.001), MaSp2a (F1,28 = 27.604, p < 0.001), and MaSp2b expression (F1,28 = 25.342, p < 0.001) expressions when protein deprived, while downregulating MaSp1b (F1,28 = 54.224, p < 0.001), while N. plumipes (c.f. response to protein deprivation by N. pilipes ) downregulated both their MaSp1a (F1,28 = 21.104, p < 0.001) and MaSp2a (F1,28 = 8.358, p = 0.007) expression when protein deprived, which corresponded with an increase in proline composition. P. graeffei significantly downregulated their MaSp1a (F1,28 = 6.587, p = 0.010) and upregulated their MaSp2a (F1,28 = 8.543, p = 0.006) expression when protein deprived.