Sexual size dimorphism describes the difference in body proportions between sexes of the same species. SSD in spiders has been well established for numerous species in the Araneae order [1,2]. For example, female gigantism is common among the Nephila, orb weaving spider [3,4]. The timing , magnitude, and molecular mechanisms of male-female size differences in the common house spider, Parasteatoda tepidariorum is unknown. Size disparities in mammals emerge at specific stages in development based on molecular signaling dispensed from the gonads. Alternatively, the origin of SSD in arthropods, specifically Arachnida, is relatively unknown, but most cell types are thought to autonomously determine sex differences. However, After observing a female spider with abnormallymale-like pedipalps, we considered the possibility that palps playa role in sending secondary signals for sexual development. The Insulin/Akt signal transduction pathway has been implicated in Drosophila melanogaster SSD. Specifically, female Drosophila are known to have elevated levels of the insulin-like peptide expression and phosphorylated Akt (signs of active insulin signaling) . This research seeks to determine if genes expressed in Drosophila, which are responsible for SSD, are also present in P. tepidariorum from the pre-juvenile to adult stages of development.