SUMMARY Imperfect synchrony between male calls occurs in the acoustically interacting bushcricket Mecopoda elongata, and males establishing the temporal leadership attract more females in choice experiments. An asymmetrical representation of leader and follower signals in pairs of direction-selective neurons of the auditory pathway was suggested to represent the neural basis for the preference of females. We investigated the time–intensity trading effect, which occurs when the temporal advantage of the leader signal is compensated, and can be reversed, by an additional sound pressure level of the follower. In behavioural arena trials the intensity trading of the preference of females for leader signals depends on the playback level; a higher sound pressure level (SPL) is needed for compensation at higher playback levels. We studied the simultaneous neuronal representation of leader and follower signals, and the time–intensity trading function in the pair of omega-neurons in the CNS. Consistent with the behavioural data, the representation of leader and follower signals can be reversed with an additional loudness of the follower, and the steepness of the trading function depends on the playback level. We also implemented data on the neuronal representation of synchronized signals in individual receivers into computer-based agents, which performed phonotaxis in a virtual sound field. Results of these simulations closely resemble those obtained from real females with respect to the overall preference under the various time–intensity trading conditions. Furthermore, in combination with the observed trading functions these simulations demonstrate, that under more realistic field conditions the ultimate success of followers in attracting females is much higher than suggested from arena trials. We discuss the evolutionary consequences for male calling strategies in synchronously calling Orthoptera.

Acoustically communicating animals often have to cope with ambient noise that has the potential to interfere with the perception of conspecific signals. Here we use the synchronous display of mating signals in males of the tropical katydid Mecopoda elongata in order to assess the influence of nocturnal rainforest noise on signal perception. Loud background noise may disturb chorus synchrony either by masking the signals of males or by interaction of noisy events with the song oscillator. Phase-locked synchrony of males was studied under various signal-to-noise ratios (SNRs) using either native noise or the audio component of noise (<9 kHz). Synchronous entrainment was lost at a SNR of −3 dB when native noise was used, whereas with the audio component still 50 % of chirp periods matched the pacer period at a SNR of −7 dB. Since the chirp period of solo singing males remained almost unaffected by noise, our results suggest that masking interference limits chorus synchrony by rendering conspecific signals ambiguous. Further, entrainment with periodic artificial signals indicates that synchrony is achieved by ignoring heterospecific signals and attending to a conspecific signal period. Additionally, the encoding of conspecific chirps was studied in an auditory neuron under the same background noise regimes.

Horned lizards (Phrynosoma) are specialized predators, including many species that primarily feed on seed harvester ants (Pogonomyrmex). Harvester ants have strong mandibles to husk seeds or defensively bite, and a venomous sting. Texas horned lizards possess a blood plasma factor that neutralizes harvester ant venom and produce copious mucus in the pharynx and esophagus, thus embedding and incapacitating swallowed ants. We used high-speed video recordings to investigate complexities of their lingual prey capture and handling behavior. Lizards primarily strike ants at their mesosoma (thorax plus propodeum of abdomen). They avoid the head and gaster, even if closer to the lizard, and if prey directional movement is reversed. Orientation of captured ants during retraction is with head first (rostral), thus providing initial mucus coating of the mandibles. Prey capture accuracy and precise handling illustrates the specificity of adaptations of horned lizards in avoiding harm, and the challenges lizards face when feeding on dangerous prey.