Assassin bug uses aggressive mimicry to lure spider prey

Abstract

Assassin bugs (Stenolemus bituberus) hunt web-building spiders by invading the web and plucking the silk to generate vibrations that lure the resident spider into striking range. To test whether vibrations generated by bugs aggressively mimic the vibrations generated by insect prey, we compared the responses of spiders to bugs with how they responded to prey, courting male spiders and leaves falling into the web. We also analysed the associated vibrations. Similar spider orientation and approach behaviours were observed in response to vibrations from bugs and prey, whereas different behaviours were observed in response to vibrations from male spiders and leaves. Peak frequency and duration of vibrations generated by bugs were similar to those generated by prey and courting males. Further, vibrations from bugs had a temporal structure and amplitude that were similar to vibrations generated by leg and body movements of prey and distinctly different to vibrations from courting males or leaves, or prey beating their wings. To be an effective predator, bugs do not need to mimic the full range of prey vibrations. Instead bugs are general mimics of a subset of prey vibrations that fall within the range of vibrations classified by spiders as 'prey'.

Dangerous mating systems: Signal complexity, signal content and neural capacity in spiders

“…Despite a limited number of studies to date, the former idea that courtship are signals distinct from prey, is supported by papers that have quantified male courtship in spider webs. For example, in the gumfooted-web spider Parasteatoda sp., males produce low amplitude but highly repetitive courtship vibrations (Wignall and Taylor, 2011), quite distinct from prey vibrations. Curiously, these Parasteatoda signals are remarkably similar to the courtship vibrations generated by the unrelated orb-web spider Argiope keyserlingi (Wignall and Herberstein, 2013a), the sheet-web spider Frontinella pyramitela (Suter and Renkes, 1984), and the black widow spider Latrodectus hesperus (Vibert et al, 2014).…”

Biology ofStenolemus giraffa(Hemiptera: Reduviidae), a web invading, araneophagic assassin bug from Australia

“…The 'luring' Portia then attacks, kills and eats the resident, lured spider. Similar luring has been recently documented for S. bituberus (Wignall & Taylor 2009, Wignall & Taylor 2010, Wignall & Taylor 2011 and has also been observed in mud-dauber wasps (Sphecidae) (Blackledge & Pickett 2000).…”

“…It is interesting that, when targeting a pholcid as prey, Portia often resembles S. giraffa by avoiding luring signals and by remaining at the edge of the web instead of entering the web completely (Jackson 1992b). In contrast to S. giraffa, S. bituberus commonly adopts tactics that appear to be designed for luring in the resident spider (Wignall & Taylor 2009, Wignall & Taylor 2010, Wignall & Taylor 2011. However, when pursuing pholcids, S. bituberus more often uses a stalking ploy, possibly as a species-specific tactic to avoid counter attacks by the spiders (Wignall & Taylor 2009).…”

First in situ observations of the deep-sea squid Grimalditeuthis bonplandi reveal unique use of tentacles

“…Krill may use low-frequency vibrations to aggregate with conspecifics [34,35]. Aggressive mimicry using vibrations has been described in the assassin bug Stenolemus bituberus, which lures spiders by plucking web silk in a way that mimics the spiders' prey [36]. Finally, the club movements may produce a recognizable hydrodynamic signal that potential prey would follow because it resembled a signal produced by its own prey or a mate.…”

“…However, other aggressive mimics do not directly resemble the appearance of models. In these cases, the mimics resemble a broader class of models rather than a specific one; or the lure may exhibit a stronger signal than the model, provoking a more intense response from the prey [36].…”