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Host location by a parasitoid using leafminer vibrations: characterizing the vibrational signals produced by the leafmining host
Author(s) -
MEYHÖFER R.,
CASAS J.,
DORN S.
Publication year - 1994
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/j.1365-3032.1994.tb01062.x
Subject(s) - biology , gracillariidae , parasitoid , lepidoptera genitalia , eulophidae , pupa , larva , context (archaeology) , host (biology) , ecology , paleontology
. The aim of this study was to characterize the vibrations produced by the apple tentiform leafminer Phyllonorycter malella (Ger.) (Lepidoptera, Gracillariidae). Host location using vibrations by one of its parasitoids Sympiesis sericeicornis Nees (Hymenoptera, Eulophidae) was postulated by Casas (1989) on the basis of detailed quantitative behavioural observations and has also been suggested by other authors on similar systems. Both host and parasitoid send and may receive vibratory signals; consequently we first attempted to characterize and classify the signals, one of the first steps required in the design of an adequate vibrational biotest. In this respect, our approach differs fundamentally from the familiar setting of host location via semiochemicals and is best framed within the context of vibratory communication. Vibrational signals produced by a moving larva and pupa were measured on several spots on the leaf using a laser vibrometer. The emitted signals were characterized by their temporal patterns of change in amplitude and frequency spectra. The vibrational patterns released by a moving larva were different from those released by a wriggling larva and a wriggling pupa in the time as well as in the frequency domains. Wriggling larvae and wriggling pupae triggered vibrations that were similar in frequency, but differed in their temporal pattern. Frequencies up to 15 kHz could be identified. The amplitudes and frequencies of the signals both decreased significantly from the tip to the base of the leaf. A wriggling pupa and a wriggling larva produced stronger signals than a foraging larva. All calculated parameters (displacement, velocity, acceleration, and duration of the signal components) of the vibrational signals were found to be in a range comparable with others used for well‐known arthropod communication systems. The vibrations produced by the host displayed distinct characteristics: they could usually be distinguished easily from background noise; could be perceived anywhere on the leaf; and were specific for a certain host stage and activity. Our findings support the hypothesis that vibration signals represent a reliable source of information to foraging parasitoids and, therefore, explain certain behavioural patterns observed in a population of S. sericeicornis females foraging in the field.