World squid fisheries

Peer reviewedPublisher PD

Sperm transfer or spermatangia removal: postcopulatory behaviour of picking up spermatangium by female Japanese pygmy squid

In the Japanese pygmy squid Idiosepius paradoxus, females often pick up the spermatangium using their mouth (buccal mass) after copulation. To examine whether the female I. paradoxus directly transfers sperm into the seminal receptacle via this picking behaviour, or removes the spermatangium, we conducted detailed observations of picking behaviour in both virgin and copulated females and compared the sperm storage conditions in the seminal receptacle between females with and without spermatangia picking after copulation in virgin females. In all observations, elongation of the buccal mass occurred within 5 min after copulation. However, sperm volume in the seminal receptacle was not related to spermatangia picking. Observations using slow-motion video revealed that females removed the spermatangia by blowing or eating after picking. These results suggest that picking behaviour is used for sperm removal but not for sperm transfer. Moreover, the frequency of buccal mass elongation was higher in copulated females than in virgin females, consistent with the sequential mate choice theory whereby virgin females secure sperm for fertilisation, while previously copulated females are more selective about their mate. Female I. paradoxus may choose its mate cryptically through postcopulatory picking behaviour

Double eggs of pharaoh cuttlefish, Sepia pharaonis Ehrenberg, 1831

Volume: 46Start Page: 97End Page: 9

THE BROWN-CHESTED FLYCATCHER RHINOMYIAS-BRUNNEATA NEW-RECORD FOR THAILAND

Volume: 105Start Page: 75End Page: 7

chez le buffle en Thailande

L’Onchocerque intradermique chez Bubalus bubalis en Thaïlande est la même espèce que celle décrite sous le nom d’O. sweetae dans les nodules intradermiques de B. bubalis en Australie.Cette identification suggère qu’il n’y a pas eu de spéciation entre les parasites des Buffles d’Australie et d’Asie.Le taxon O. indice Sweet, 1915, comprend deux espèces distinctes : l’une dans les muscles périmusculaires de Bos indicus est probablement O. gibsoni (et donc, l’espèce O. indica, basée essentiellement sur la description de ce matériel, doit tomber en synonymie) ; l’autre dans les nodules intradermiques de B. bubalis ne diffère pas d’O. sweetae. Pour admettre la distinction entre O. cebei, un parasite chez le même hôte d’Hanoï, et O. sweetae, il faudrait démontrer que la présence ou l’absence des papilles nettement précloacales est un caractère valide pour séparer ces espèces