Selective phonotaxis of female crickets under natural outdoor conditions

Abstract

Acoustic mate choice in insects has been extensively studied under laboratory conditions, using different behavioural paradigms. Ideally, however, mate choice designs should reflect natural conditions, including the physical properties of the transmission channel for the signal. Since little is known about the discrimination ability of females between male song variants under natural conditions, we performed phonotaxis experiments with female field crickets (Gryllus bimaculatus) outdoors, using two-choice decisions based on differences in carrier frequency, sound pressure level, and chirp rate. For all three song parameters, minimum differences necessary for a significant preference between two song models were considerably larger outdoors compared to laboratory conditions. A minimum amplitude difference of 5 dB was required for a significant choice in the field, compared to only 1–2 dB reported for lab-based experiments. Due to the tuned receiver system, differences in carrier frequency equal differences in perceived loudness, and the results on choice for differences in carrier frequency corroborate those in amplitude. Similarly, chirp rate differences of 50 chirps/min were required outdoors compared to only 20 chirps/min in the lab. For predictions about patterns of sexual selection, future studies need to consider the different outcomes of mate choice decisions in lab and field trials.

How Developmental and Behavioural Plasticity in the Field Cricket is Influenced by the Acoustic Social Environment and Anthropogenic Noise

“…Female preference function shapes for chirp rate were generally linear, with preference increasing as chirp rate increased in the artificial signals. These results are consistent with previous findings indicating that female crickets prefer males who signal with higher chirp rates that are energetically costly to produce (Simmons 1988;Wagner & Reiser 2000;Scheuber et al 2004;Hirtenlehner & Römer 2014;Pollack & Hoy 1981).…”

Insect acoustic communication: The role of transmission channel and the sensory system and brain of receivers

“…Given these distorted directional cues, how can the phonotactic behaviour of insects cope with these conditions? Only three studies have quantified phonotactic tracks of acoustic insects towards a sound source in no‐choice or choice trials outdoors, two for field crickets (Hirtenlehner & Römer, ; Mhatre & Balakrishnan, ) and one for a parasitoid fly approaching the target in flight (Tron & Lakes‐Harlan, ). The significant findings were as follows: in no‐choice trials, all female crickets approached the target, but the distance covered was significantly larger compared to similar laboratory trials.…”

Insect Hearing

“…These could, however, be refi ned to better refl ect the spatial and acoustic context experienced by receivers in the fi eld (Hirtenlehner and Römer 2014 ). The acoustic context can be highly variable in the wild depending on signaler densities, source SPLs, signal structure, habitat, and movement, and it is necessary to validate results obtained under laboratory conditions by testing them in realistic fi eld scenarios.…”