Parasitoid vibrations as potential releasing stimulus of evasive behaviour in a leafminer

Abstract

Abstract. The aim of this study was to characterize the vibratory signals produced by the parasitoid Sympiesis sericeicornis Nees (Hymenoptera: Eulophidae) while foraging on apple leaves infested by one of its hosts, the spotted tentiform leafminer Phyllonorycter malella (Ger.) (Lepidoptera: Gracillariidae).This leafminer changes its behaviour as a function of the parasitoid's behaviour to escape parasitization.We propose that the leafminer uses vibrations triggered by the parasitoid to detect the presence of its enemy.We measured vibrations produced by a foraging parasitoid on a mine with a laser vibrometer.By recording concurrently the behaviour of the parasitoid on video, vibrations could be assigned to particular behaviours.Subsequently, vibrations were characterized by their dominant frequencies and intensities.The behaviours Landing and Take‐off both produced strong impact‐like vibrations characterized by an initial irregular phase during which frequencies up to 25 kHz occurred followed by a slow decaying regular phase.Vibrations elicited by Moving, Standing and Probing showed no clear temporal pattern.During Probing, dominant frequencies of up to 5.6 kHz were observed frequently at intensities well above the background noise (>10 dB).During Moving and Standing, vibrations were more scarce and of lower frequencies and intensities.Due to their impact‐like nature, vibrations produced by Landing and Take‐off are probably not specific to the parasitoid.Vibrations produced by Moving and Standing are difficult to detect and not reliable because of their non‐specificity.Therefore, only Probing provides a reliable and detectable source of information for the host.The vibrations elicited during Probing could account for the evasive behaviour that is observed in this and other leafminers.

Temporal pattern cues in vibrational risk assessment by embryos of the red-eyed treefrog, Agalychnis callidryas

“…Leafmining caterpillars are perhaps the best studied case of antipredator behavior cued by substrateborne vibrations. Their defensive behavior is elicited by broadband vibrations produced as a parasitoid wasp probes the mine with her ovipositor (Bacher et al, 1996;Bacher et al, 1997;Meyhofer et al, 1997;Djemai et al, 2001).…”

“…There is increasing evidence that both prey and their predators can use substrate-borne vibrations in their interactions (Bleckmann, 1985;Pfannenstiel et al, 1995;Bacher et al, 1996;Meyhofer et al, 1997;Randall and Matocq, 1997;Burger, 1998;Brownell and Van Hemmen, 2001;Warkentin, 2005). Indeed, vibrational cues as a means of predator detection offer certain advantages over other sensory modalities.…”

Vibration–mediated interactions in a host–parasitoid system

“…Within the parasitoid's foraging sequence, o ipositor insertion is the only behavioural event that produces high frequency and high intensity vibrational signals, while pausing and searching vibrations are rather scarce and of low frequency and intensity (Bacher et al 1996). We therefore compared the host's responses to o ipositor insertion with its reaction when the parasitoid was searching or pausing.…”

“…Vibrations produced by host larvae contain highly reliable and detectable information on both the host instar and the host's activities (Meyho$ fer et al 1994 a, b). The parasitoid's insertion of the ovipositor into the mine also produces vibrations that are highly characteristic, and which can be used for evasive manoeuvres by the host (Bacher et al 1994). Manipulative experiments enabled us to capture on video film the behaviour of both host and parasitoid and to analyse the resulting combined ethograms.…”

Is it safe? Red-eyed treefrog embryos assessing predation risk use two features of rain vibrations to avoid false alarms

“…Thus, their properties (peak frequency, amplitude, etc.) often have broad and variable probability distributions that can overlap with those of benign stimuli (Bacher et al 1996;Casas et al 1998;Warkentin 2005;Caldwell et al 2009). Such similarity may be particularly likely for vibrational and acoustic stimuli because they are strongly affected by the physical properties of the vibrating structures that produce and propagate them, regardless of the original source of excitation (Ginsberg 2001).…”