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Predators often search for prey while moving through the environment, but there are important exceptions, including the way sedentary predators sometimes rely on signals for drawing prey to within striking distance 1,2. Some spiders, for instance, leave the remnants of previously-captured prey in their webs where they function as static lures that effectively attract a diverse array of additional prey 3456. However, important questions remain concerning how specific the targeted prey may be and how dynamic, instead of static, signalling might be. With these questions as our rationale, we initiated research on Araneus ventricosus (L. Koch, 1878), an orb-weaving spider, as the predator and the firefly Abscondita terminalis males as the prey (Figure 1A–C). Using two lanterns situated on their abdomen (Figure 1D,F), A. terminalis males make female-attracting multi-pulse flash trains (Figure 1J), whereas sedentary females attract males by making single-pulse signals (Figure 1C,K) with a single lantern (Figure 1E,G). Drawing from extensive field observations, we propose that A. ventricosus practices deceptive interspecific communication by first ensnaring firefly males in its web and then predisposing the entrapped male fireflies to broadcast bioluminescent signals that deviate from female-attracting signals typically made by A. terminalis males and instead mimic the male-attracting signals typically made by females. The outcome is that the entrapped male fireflies broadcast false signals that lure more male fireflies into the web. Fu et al. find that the orb-weaving spider Araneus ventricosus manipulates the bioluminescent signals of its male firefly prey Abscondita terminalis and thus lures more male fireflies into its web. [ABSTRACT FROM AUTHOR]

Proficiency at planning is known to be part of the exceptionally complex predatory repertoire of Portia , a genus of jumping spiders (Salticidae) that specialize in preying on other spiders. This includes proficiency at choosing between two detour routes, with only one leading to otherwise inaccessible prey. Less is known about Portia 's proficiency at making strategic decisions pertaining to whether a detour is required or not. Using Portia africana , we investigated this by having lures (prey or leaf pieces) visible at the beginning of a trial but not later, and by using water to restrict P. africana 's freedom of movement. A detour path was always present, but sometimes a causeway was also present, allowing direct access to lures. After seeing prey, P. africana more often took the causeway when present and, when absent, more often took the detour path. After seeing leaf pieces, P. africana never took the detour path., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2019. Published by The Company of Biologists Ltd.)