Some Factors Influencing Egg Laying in Oncomelania Nosophora and Oncomelania Quadrasi, Intermediate Hosts of Schistosoma Japonicum 1

Cercariae (juvenile trematodes with tails) emerge from mollusk intermediate hosts and swim toward definitive hosts or encystment objects. The locomotor power is furnished by the tail. Upon reaching a suitable host or encystment object, the tail is cast off and the cercariae penetrate and/or encyst. Ultrastructural studies of cercariae are sparse. There is even lessUltrastructural studies of cercariae are sparse. There is even less information about the tail structure; and body-to-tail morphology has been documented only for Acanthatrium oregonense and Schistosoma japonicum.

Download Full-text

Factors influencing growth of juvenile spruce grouse

Canadian Journal of Zoology ◽

10.1139/z81-245 ◽

1981 ◽

Vol 59 (9) ◽

pp. 1790-1795 ◽

Cited By ~ 3

Author(s):

Norman W. S. Quinn ◽

Daniel M. Keppie

Keyword(s):

Growth Rate ◽

Body Weight ◽

New Brunswick ◽

Growth Rates ◽

Egg Laying ◽

Maternal Influence ◽

Juvenile Growth ◽

Factors Influencing ◽

Differential Timing

The influences of date of hatch, and age and prelaying body weight of brood female on the growth rate of juvenile spruce grouse (Canachites canadensis) were studied in central New Brunswick in 1977 and 1978. Because of differential timing of hatch of broods of adult and yearling females, it was not clear whether a difference in juvenile growth rates during 5–14 days of age in 1977 was related to date of hatch, age of brood female, or both. Differences in juvenile growth rates within and between years apparently were not influenced by body weight of brood females prior to egg laying. Results suggest that posthatch factors are more important in determining growth rate than a prehatch or "maternal" influence.

Download Full-text

Factors influencing fledgling production in little penguins (Eudyptula minor)

Wildlife Research ◽

10.1071/wr03071 ◽

2004 ◽

Vol 31 (3) ◽

pp. 339 ◽

Cited By ~ 3

Author(s):

C. Knight ◽

T. Rogers

Keyword(s):

Breeding Season ◽

Egg Laying ◽

Breeding Biology ◽

Single Variable ◽

Nesting Habitat ◽

High Quality ◽

Factors Influencing ◽

Little Penguin ◽

Significant Model

An eight-year study was conducted on the breeding biology of the little penguin population at Lion Island. Forwards-selection Poisson regressions were used to determine whether variables such as year, date of lay, years since banding of each parent (indicator of age) and habitat influenced the fledgling numbers and average fledgling weight for adult pairs. 'Date of lay' provided the most significant model of fledgling numbers, while 'habitat' and 'year' as single-variable models also significantly influenced fledgling numbers. 'Date of lay' provided the most significant model of average fledgling weight. Future monitoring of the Lion Island colony therefore should focus on monitoring egg laying at the start of the breeding season, and maintaining high-quality nesting habitat.

Download Full-text