Biotremology in spiders
Spiders are known to use substrate vibrations in various communication contexts. Sensitive slit sensillae on the legs and other body parts detect these signals. Often, several vibratory signals or signal-components are produced by different production mechanisms, namely percussion, tremulation, and stridulation. Additionally, other communication modalities such as olfaction or vision are used to produce multimodal communication signals.
We (link to Monika & Gabriele) investigate vibrational signals of Pisaura mirabilis, the nursery web spider, and Argiope bruennichi, the wasp spider. Both spider species use vibrations during courtship to signal male presence, species identity or quality, and/or to reduce the risk of being attacked by the female (thus being mistaken as prey).
Males of the nursery web spider, Pisaura mirabilis, often capture prey, wrap them in silk and offer these gifts to females. Upon female acceptance, copulation occurs while the female consumes the gift (Austad & Thornhill, 1986). Nuptial feeding is under sexual selection as females exhibit strong preferences for males offering gifts (Albo, Bilde & Uhl, 2013). In the Bachelor’s projects of Alexandra Machnis and Timon Möller, vibrational signals of P. mirabilis will be recorded using a Laser-Doppler-Vibrometer in different experimental setups to reveal if signals are related to male quality, nuptial gift presence and size.
In the advertised Bachelor or Master project, substrate-borne vibrational signals of the wasp spider A. bruennichi males (and females) will be recorded using a Laser-Doppler-Vibrometer to assess the intra- and interindividual variability of communication signals during courtship. Recordings in the laboratory and in the field will reveal possible plasticity and impacts of environmental factors on the communication signals. Additionally, morphological parameters of the spiders will be measured to investigate a correlation between certain conditional factors and courtship signals.