03010nas a2200181 4500008004100000245009100041210006900132520234200201653002902543653001202572653002402584653004202608653003302650653002302683100002202706700001902728856008102747 2013 eng d00aDiversity of acoustic tracheal system and its role for directional hearing in crickets0 aDiversity of acoustic tracheal system and its role for direction3 a

Background: Sound localization in small insects can be a challenging task due to physical constraints in deriving sufficiently large interaural intensity differences (IIDs) between both ears. In crickets, sound source localization is achieved by a complex type of pressure difference receiver consisting of four potential sound inputs. Sound acts on the external side of two tympana but additionally reaches the internal tympanal surface via two external sound entrances. Conduction of internal sound is realized by the anatomical arrangement of connecting trachea. A key structure is a trachea coupling both ears which is characterized by an enlarged part in its midline (i.e., the acoustic vesicle) accompanied with a thin membrane (septum). This facilitates directional sensitivity despite an unfavorable relationship between wavelength of sound and body size. Here we studied the morphological differences of the acoustic tracheal system in 40 cricket species (Gryllidae, Mogoplistidae) and species of outgroup taxa (Gryllotalpidae, Rhaphidophoridae, Gryllacrididae) of the suborder Ensifera comprising hearing and non hearing species.

Results: We found a surprisingly high variation of acoustic tracheal systems and almost all investigated species using intraspecific acoustic communication were characterized by an acoustic vesicle associated with a medial septum. The relative size of the acoustic vesicle - a structure most crucial for deriving high IIDs - implies an important role for sound localization. Most remarkable in this respect was the size difference of the acoustic vesicle between species; those with a more unfavorable ratio of body size to sound wavelength tend to exhibit a larger acoustic vesicle. On the other hand, secondary loss of acoustic signaling was nearly exclusively associated with the absence of both acoustic vesicle and septum.

Conclusion: The high diversity of acoustic tracheal morphology observed between species might reflect different steps in the evolution of the pressure difference receiver; with a precursor structure already present in ancestral non-hearing species. In addition, morphological transitions of the acoustic vesicle suggest a possible adaptive role for the generation of binaural directional cues.

10aAcoustic tracheal system10acricket10adirectional hearing10aInteraural intensity difference (IID)10aPressure difference receiver10aSound localization1 aSchmidt, Arne, KD1 aRömer, Heiner uhttp://frontiersinzoology.biomedcentral.com/articles/10.1186/1742-9994-10-6100356nas a2200109 4500008004100000245006200041210006200103300001200165490000700177100001600184856004600200 1982 eng d00aAcoustic communication and baffling behaviors of crickets0 aAcoustic communication and baffling behaviors of crickets a33–440 v651 aForrest, TG uhttps://bio.acousti.ca/zh-hans/node/5314201380nas a2200121 4500008004100000245013600041210006900177300001200246490000800258520092300266100002301189856004601212 1987 eng d00aThe Efficiency of Sound Production in Two Cricket Species, Gryllotalpa Australis and Teleogryllus Commodus (Orthoptera: Grylloidea)0 aEfficiency of Sound Production in Two Cricket Species Gryllotalp a107-1190 v1303 a

1. Males of Gryllotalpa australis (Erichson) (Gryllotalpidae) and Teleogryllus commodus (Walter) (Gryllidae) produced their calling songs while confined in respirometers.

2. G. australis males used oxygen during calling at a mean rate of 4.637 ml O2 h−1, equivalent to 27.65 mW of metabolic energy, which was 13 times higher than the resting metabolic rate. T. commodus males used oxygen during calling at a rate of 0.728 ml O2 h−1, equivalent to 4.34 mW, which was four times the resting metabolic rate.

3. The sound field during calling by males represents a sound power output of 0.27 mW for G. australis and l.51 × l0.3 mW for T. commodus.

4. The efficiency of sound production was 1.05% for males of G. australis and 0.05% for males of T. commodus. Comparison with other insect species suggests that none is more than a few percent efficient in sound production.

1 aKavanagh, Mark, W. uhttps://bio.acousti.ca/zh-hans/node/4784500413nas a2200121 4500008004100000245008500041210006900126260001400195300001000209490000700219100001900226856004600245 1951 eng d00aThe Seasonal Succession of Orthopteran Stridulation near Raleigh, North Carolina0 aSeasonal Succession of Orthopteran Stridulation near Raleigh Nor cJune 1951 a87-950 v671 aFulton, B., B. uhttps://bio.acousti.ca/zh-hans/node/43232