Ecdysteroids, as the key growth hormones, regulate moulting, metamorphosis and reproduction in arthropods. Ecdysteroid biosynthesis is catalysed by a series of cytochrome P450 monooxygenases (CYP450s) encoded by Halloween genes, including spook (spo), phantom (phm), disembodied (dib), shadow (sad) and shade (shd). The ecdysteroid biosynthesis in insects is clear with 20‐hydroxyecdysone (20E) as the main ecdysteroid. However, the information on the major ecdysteroids in arachnids is limited. In this study, Halloween genes spo, dib, sad and shd, but not phm, were identified in the pond wolf spider, Pardosa pseudoannulata. Phylogenetic analysis grouped arachnid and insect Halloween gene products into two CYP450 clades, the CYP2 clan (spo and phm) and the mitochondrial clan (dib, sad, and shd). In P. pseudoannulata, the temporal expression profile of the four Halloween genes in concurrence with spiderling moulting with steady increase in the course of the 2nd instar followed by a rapid dropdown once moulting was completed. Spatially, the four Halloween genes were highly expressed in spiderling abdomen and in the ovaries of female adults. In parallel, ponasterone A (PA), but not 20E, was detected by LC–MS/MS analysis in P. pseudoannulata, and it was demonstrated as a functional ecdysteroid in the spider by accelerating of moulting with PA addition. The present study revealed the different ecdysteroid biosynthesis pathways in spiders and insects.
Authors' Contribution ZK planned the experiments, performed the statistical analyses, wrote and directed this project. DŞ collected the data and wrote this manuscript. MÖ collected data. ÜÖ performed the statistical analyses. OA revised the manuscript.
Due to the fact that they catch and consume insect pests, cockroaches, and other domestic soft-bodied pests in crops, Heteropoda spiders are highly important predator in tropical and subtropical regions. As with other vagrant spiders, pantropical huntsman spiders do not use webs to capture prey. Their great speed and strong chelicerae (jaws) are used to capture the insects on which they feed. Venom is also injected into the prey from glands extending from the chelicerae into the cephalothorax. In this study, more than 227 individuals belonging to six Heteropoda spiders were collected from Xishuangbanna Dai Autonomous Prefecture and brought back to lab, and then stored in 75% ethanol. Among which 64 individuals were males and 163 individuals were females. A total of six known species of the genus Heteropoda are described: Heteropoda dagmarae Jäger and Vedel, 2005, H. onoi Jäger, 2008, H. simplex Jäger and Ono, 2000, H. tetrica Thorell, 1897, H. venatoria (Linnaeus, 1767) and H. zuviele Jäger, 2008. Our findings provide new record for H. dagmarae from China, adding more knowledge to Heteropoda species distribution in China, and may help to study the biogeography and dispersal route of Heteropoda species. Our results also provide a little information for the origin and evolution study of Heteropoda genus, because no author has published any molecular phylogenetic study on this genus. We also provide description, illustration, and distribution map for each species in the current paper
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