Food limitation of population density in the orb-wed spider,Nephila clavata |
| |
Authors: | Tadashi Miyashita |
| |
Institution: | (1) Laboratory of Forest Zoology, Faculty of Agriculture, University of Tokyo, Bunkyo-ku, 113 Tokyo, Japan |
| |
Abstract: | Summary Field studies were conducted to clarify whether variation in food availability among habitats influences population density,
and whether population density has a negative effect on foraging success in the orb-web spider,Nephila clavata.
Lifetime food consumption per individual (i.e., foraging success) strongly correlated with mean body size of adult females
and mean fecundity in populations. Also, there was a positive correlation between foraging success and population density.
Since foraging success reflected potential prey availability in the habitat, food resource appeared to be a limiting factor
for populations in this spider. Mean fecundity per individual correlated with population density of the following year, suggesting
that decreased reproduction is a major component of food limitation on population density. Consistent defferences in mean
body size between particular sites were observed over years, while such difference was less obvious in density. Thus, ranking
of food abundance among habitats seems to be predictable between years. A field experiment revealed that an artificial increase
in population density had no negative effect on the feeding rate of individuals, suggesting that intraspecific competition
for food is not important in this species. |
| |
Keywords: | food limitation intraspecific competition arthropod predators spider population density |
本文献已被 SpringerLink 等数据库收录! |
|