About This Project

For a male black widow spider, life is a series of deadly challenges. He must first make a dangerous journey to find a female, then convince her to mate with him rather than cannibalize him before he can pass on his genetic material. At every stage, he will face fierce competition from rival males with the same agenda. In this project, we seek to understand how male black widows use chemicals produced by females and rivals to gain a competitive edge in the race to find and secure a mate.

Ask the Scientists

What is the context of this research?

Black widows are influenced by chemical information throughout their lives. In the laboratory, chemical cues indicating the number of nearby rival males and the availability of females affect the timing of a male’s development, and thus his competitive ability. Researchers in our lab recently discovered that male widow spiders can mate with immature females, a tactic that allows males to mate more quickly and more often. However, as far as we know, only adult females produce the attractive chemical signal that allows males to locate them. So how do males detect valuable but chemically hidden immature females? We hypothesize that mate-searching males use chemical cues from nearby adult females and the draglines of rivals to evaluate the competitive landscape and find immature females.

What is the significance of this project?

Despite decades of research on black widow mating behaviour, immature mating was reported only this year. There is much still to learn about these spiders, and fieldwork is essential for making new discoveries and supporting or challenging what we already know from laboratory experiments. This project will shed light on the largely overlooked role of male-produced chemical cues in spider communication systems. More broadly, the results will increase our understanding of chemical communication in spiders, some of which are invasive or considered pests in certain areas. Such an understanding in insects has been crucial to the development of pesticide-free control strategies for pest species (e.g. using female chemical attractants to trap and remove males from a population).

What are the goals of the project?

The goal of this project is to determine how male black widows use chemical cues to avoid or succeed in competition with rival males. We will answer the following specific questions through observational and experimental studies of a natural population of western black widow spiders:

How does the density of rival males and potential mates affect the timing of male development, their competitive ability, and their mating success?

How do males find immature females and what traits allow them to do so successfully?

How does the silk left behind by rivals influence the behaviour of mate-searching males?