02063nas a2200181   4500008004100000245009900041210006900140520137900209653002101588653001701609653001401626653002601640653001201666100002801678700002201706700002201728856013101750       2019                        eng d00aGrowling from the gut: co-option of the gastric mill for acoustic communication in ghost crabs0 aGrowling from the gut cooption of the gastric mill for acoustic 3 a<p>Animal acoustic communication systems can be built upon co-opted structures that become specialized for sound production or morphological novelties. The ghost crab, Ocypode quadrata, evolved a novel stridulation apparatus on the claws that is used during agonistic interactions, but they also produce a rasping sound without their claw apparatus. We investigated the nature of these sounds and show that O. quadrata adopted a unique and redundant mode of sound production by co-opting the gastric mill (grinding teeth of the foregut). Acoustic characteristics of the sound are consistent with stridulation and are produced by both male and female crabs during aggressive interactions. Laser Doppler vibrometry localized the source of maximum vibration to the gastric region and fluoroscopy showed movement of the gastric mill that coincided with stridulation. The lateral teeth of the gastric mill possess a series of comb-like structures that rub against the median tooth to produce stridulation with dominant frequencies below 2 kHz. This previously undescribed gastric stridulation can be modulated and provide a means of assessment during aggressive interactions, similar to the use of the claw stridulation apparatus. This functional redundancy of stridulation in crabs offers unique insights into the mechanisms of evolution of acoustic communication systems.</p>
10aanimal behaviour10abioacoustics10aCrustacea10afunctional morphology10aOcypode1 aTaylor, Jennifer, R. A.1 adeVries, Maya, S.1 aElias, Damian, O.  uhttps://royalsocietypublishing.org/doi/10.1098/rspb.2019.1161https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2019.116101918nas a2200157   4500008004100000245009100041210006900132260002000201300001100221490000600232520130900238100002301547700002201570700003001592856013801622       2017                        eng d00aMultimodal communication in courting fiddler crabs reveals male performance capacities0 aMultimodal communication in courting fiddler crabs reveals male   cDec-28-20172018  a1610930 v43 a<p>Courting males often perform different behavioural displays that demonstrate aspects of their quality. Male fiddler crabs, Uca sp., are well known for their repetitive claw-waving display during courtship. However, in some species, males produce an additional signal by rapidly stridulating their claw, creating a &lsquo;drumming&rsquo; vibrational signal through the substrate as a female approaches, and even continue to drum once inside their burrow. Here, we show that the switch from waving to drumming might provide additional information to the female about the quality of a male, and the properties of his burrow (multiple message hypothesis). Across males there was, however, a strong positive relationship between aspects of their waving and drumming displays, suggesting that drumming adheres to some predictions of the redundant signal hypothesis for multimodal signalling. In field experiments, we show that recent courtship is associated with a significant reduction in male sprint speed, which is commensurate with an oxygen debt. Even so, males that wave and drum more vigorously than their counterparts have a higher sprint speed. Drumming appears to be an energetically costly multimodal display of quality that females should attend to when making their mate choice decisions.</p>
1 aMowles, Sophie, L.1 aJennions, Michael1 aBackwell, Patricia, R. Y.  uhttp://rsos.royalsocietypublishing.org/lookup/doi/10.1098/rsos.161093https://syndication.highwire.org/content/doi/10.1098/rsos.161093