Presence Of Adult Males Research Articles

Sexual conditions in a population of the Polychaete Ophryotrocha labronica La Greca & Bacci from Naples

Abstract The sexual conditions of a strain of Ophryotrocha labronica from Naples were studied. Unlike the hermaphroditic Leghorn strain, the Naples strain is gonochoristic. Isolation and group isolation experiments, similar to those previously carried out by other writers on O.puerilis, demonstrated sexual stability in both males and females. The mean percentage of males is 31.6 ± 1.1 in the progeny of individual females and 31.8 ± 0.77 in populations made up from many egg masses. The sex ratio was not affected when newly released larvae were isolated individually, nor by the presence of adult males or females in the rearing bowls during the period of growth. There was a significant negative correlation between the number of eggs in the egg masses and the percentage of males, but no correlation between the population density in the bowls and the sex ratio. It is suggested that sex determination occurs during the early period of development and that the sex is stable when larvae are released from the egg mass.

Silk Production in Adult Males of the Wolf Spider Pardosa Amentata (Cl.) (Araneae, Lycosidae)

A method is described for selectively sealing the spinnerets of adult males of Pardosa amentata. The silk produced by males with various spinnerets sealed was investigated. Males, by themselves, in the presence of adult males and in the presence of adult females were tested. It was found that all the silk produced came from the anterior spinnerets. This indicates that no silk is produced from the glandulae aciniformes under these circumstances. The glandulae ampullaceae produce the drag-lines and the glandulae piriformes the attachment discs. Silk from the glandulae piriformes is used to produce two further silk patterns when the male is in the presence of other males or females. The nature of these silk patterns is dependent on the manner in which the male walks in the two situations and the striking feature about this silk production by the glandulae piriformes is that during courtship large quantities of piriform silk are produced compared with the quantities produced in other situations. The meaning of the term drag-line is discussed.

Identification of Male Schistosomes in Uncommon Sites

IN view of the difficulty of identifying adult schistosomes except by the shape of their ova, the presence of adult males in a site where only one species is known to occur strongly supports the opinion that the worms may belong to that species, even though easily identified adults belonging to another species are present in the same host.