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Nachrichten, Termine, Experten
According to a new research study by researchers from Greifswald and Canada, black widows (Latrodectus hesperus) use a unique scent strategy to find their mate. A chemical pheromone slowly decomposes on the female's web, creating an attractant that lasts for weeks, attracting males and governing their courtship.
The study, published in the Journal of Chemical Ecology https://link.springer.com/article/10.1007/s10886-025-01590-6 in 2025, shows the spider’s multi-stage and strategically structured flirting behaviour. Unlike many insects, which only release their pheromones at certain times, female widow spiders use their web as a long-term scent transmitter. The pheromone components on the web have a dual function: on direct contact, they trigger characteristic mating behaviour in the males. At the same time, these substances slowly decompose, releasing an aromatic attractant that reminds us humans of “cheesy socks". But male spiders find the scent highly attractive and are attracted from a distance. First author Dr. Andreas Fischer from the University of Greifswald says: "What I found particularly exciting about the results was that the females adapt the intensity of their scent signals to the time of year. Although they lure males all year round, they are most attractive when most males are looking for a mate." Before Fischer began his research in Greifswald, he worked at Simon Fraser University in Canada.
In the laboratory, the team chemically analysed the black widow's webs and identified the messenger substances. The researchers also carried out behavioural experiments with male spiders on special test apparatus. Field experiments on a beach showed that the synthetic scent also attracts males in the wild. Monthly measurements from a one-year field study clearly showed that females adapt their attractiveness to the seasons and that day length probably informs them of the upcoming mating season.
"The black widows demonstrate astonishingly sophisticated communication skills: with a complex chemical interplay of flavours and odours, the females significantly increase their chances of successful mating," says biologist Andreas Fischer.
Further information
Publication: Fischer, A., Fischer, A.J., Gries, R. et al. Identification and Seasonal Abundance of Web- and Air-Borne Sex Pheromone Components of Western Black Widow Spiders, Latrodectus hesperus. J Chem Ecol 51, 36 (2025). https://doi.org/10.1007/s10886-025-01590-6
Link to Dr. Fischer’s page https://zoologie.uni-greifswald.de/struktur/abteilungen/allgemeine-und-systemati...
Contact at the University of Greifswald
Andreas Fischer Ph.D. M.P.M.
Postdoctoral Research Associate
Zoological Institute and Museum
Loitzer Straße 26, 17489 Greifswald
Tel: +49 3834 420 4286
andreas.fischer@uni-greifswald.de
A female black widow (Latrodectus hesperus) on her web.
Source: Andreas Fischer
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A female black widow (Latrodectus hesperus) on her web.
Source: Andreas Fischer
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