Silent listeners: can preferences of eavesdropping midges predict their hosts’ parasitism risk?

The sound of a blood meal: Acoustic ecology of frog‐biting midges (Corethrella) in lowland Pacific Costa Rica

“…The preferred frequency bandwidth found in the midges from La Gamba was 200–650 Hz, with an effective upper threshold at ~4 kHz. Similar upper limits to hearing have been found in frog‐biting midges from southern Brazil (Caldart, Santos, Iop, Pinho, & Cechin, ) and Borneo (Meuche et al, ). Frog‐biting midges were not attracted to continuous tones (>16 s) but clearly required pulsed auditory stimulation (on–off patterns) with very short inter‐pulse durations of down to 5 ms being sufficient for stimulus recognition.…”

“…The attractiveness of recorded natural calls varied greatly, as it has been shown in previous studies (Borkent, ; Caldart et al, ; McKeever & French, ; Meuche et al, ), suggesting a selective perception or preference for certain call characteristics. The advertisement call of the Giant Bullfrog ( L. savagei ) was most attractive to frog‐biting midges, more than an order of magnitude more attractive than the calls of other frogs.…”

“…Such “universal” preferences for acoustic traits have been described for female frogs (Ryan & Keddy‐Hector, ) and might apply for Corethrella as well. However, frequency preferences/acoustic templates appear to differ between localities (compare Meuche et al, ), indicating that sensory tuning in Corethrella might have evolved in close correspondence to local host communities. The outstanding attractiveness of the Giant Bullfrog's call ( L. savagei ) to midges agrees with direct observations made at the study site: On several occasions, large numbers (up to >50) of aggregating midges could be collected from this host.…”

“…Trypanosome infections can be pathogenic (Bardsley & Harmsen, ), and therefore, corethrellid preferences for host signal properties may create a strong selective force influencing signal evolution in their anuran host species. As yet there is no direct evidence for this, but Meuche et al () found that, among a set of Bornean frog species, those with midge‐attractive calls were also the ones with the highest rates of trypanosome infections.…”

“…Although frog-biting midges have generated much interest for their unusual phonotactic behavior in recent years (Amaral & Pinho, 2015;Bernal et al, 2006;Borkent, 2008, ;Borkent & Grafe, 2012), many aspects of their interaction with anurans and the selective pressures they exert on their hosts remain poorly studied. Costs imposed by frog-biting midges on blood hosts could be substantial, ranging from irritation (indicated by defensive behaviors) and loss of blood (possibly substantial (Camp, 2006)) to an increased risk of infection with pathogens (Meuche, Keller, Ahmad Sah, Ahmad, & Grafe, 2016). Among such pathogens, trypanosome protozoans (Kinetoplastida: Trypanosomatidae) may represent the most important and diverse group of antagonists (Ferreira et al, 2015;Desser, 2001;Woo & Bogart, 1983), and acoustically oriented frog-biting midges are thought to be among the most relevant vectors of trypanosomes in frogs (Bernal & Pinto, 2016;Borkent, 2008;Johnson, Young, & Butler, 1993).…”