X0-sex-determination

Guides

• Atypus karschi

  Karsch's Purseweb Spider

  Atypus karschi is a mygalomorph spider native to East Asia (Korea, China, Taiwan, Japan) that has been introduced and established in southeastern Pennsylvania, USA. It constructs distinctive camouflaged tubular purse-webs attached to trees, shrubs, or walls, with a portion buried underground. The species was previously misidentified in North America as A. snetsingeri, but genetic analysis confirmed conspecificity with Asian populations. It is the first documented case of an introduced purse-web spider.

  mygalomorphpurse-web-spiderintroduced-speciesballooningcrypticcitizen-sciencePennsylvaniaEast-AsiaAtypidaeX0-sex-determination

• Timema californicum

  California timema

  Timema californicum is a sexually dimorphic walkingstick insect endemic to California. Males are smaller than females and possess conspicuous cerci used to grasp females during copulation. The species exhibits hemimetabolous development with gradual morphological changes: hatchlings are phenotypically identical between sexes, juveniles show minor differences, and adults display pronounced sexual dimorphism. Males complete development with one fewer moult than females.

  PhasmidaTimematidaewalkingstickstick-insectCalifornia-endemicsexual-dimorphismhemimetabolousX0-sex-determination