Western Black Widow

Latrodectus hesperus can be found in the South-western regions of Canada, from British Columbia to Manitoba, along the Pacific Coast and throughout Texas, Oklahoma and Kansas in the U.S., and in Mexico. They are commonly found near the Canada-US border, as well as less commonly throughout the grasslands of the Canadian Prairies in Western Canada.

The female is stimulated upon contact of a male's web, and vice versa. Male and female L. hesperus produce sexually-specific scents that are combined with their silk; each sex responds by initiating mating when it comes in contact with a web of the opposite sex. On initiating courting, the male L. hesperus will utilize its tarsi to tap the threads of the female's web. The male will continue this tapping gesture with its pedipalps as it actively begins to explore the web. This exploration is intermixed with resting bouts. The male's body spasms, producing a high frequency vibration throughout its abdomen. In many instances, the female will not accept the male's sexual display and will scare the male away. In some instances, the females will violently jerk their abdomen, similar to courting male displays, which ultimately leads to a positive reaction from the males and a more successful insemination. One strategy performed by the male L. hesperus to ensure a successful courtship is to minimize the female's escape route options within its own web. This is accomplished by the male severing the female's web at various locations that it believes could provide the female with a course of action to avoid the male. Once the male has successfully made contact with the female's body, it swoons the female by gently stroking various parts of its body. …