Fusao Nakasuji

Quantitative evaluation of predation by spiders on the green rice leafhopper,Nephotettix cincticeps Uhler, by a sight-count method

A sight-count method for evaluation of predation by spiders on the green rice leafhopper,Nephotettix cincticeps was proposed and its applicability was tested under natural conditions. The number (n) of leafhoppers preyed on by spiders per rice hill per day was estimated by the formula: (1)

Dietary items of predacious aquatic bugs (Nepoidea: Heteroptera) in Japanese wetlands

n = \frac{{F \cdot C}}{P}

Egg size of skippers (Lepidoptera: Hesperiidae) in relation to their host specificity and to leaf toughness of host plants

whereF is the frequency of predation observed per hill:P is given by dividing the time spent feeding on prey by 24 hours; andC refers to the total amount of feeding activity expressed in terms of the activity during the standard time interval. The total number (N) of prey attacked during the specified period can be given as follows: (2)

The effects of wild cruciferous host plants on morphology, reproductive performance and flight activity in the diamondback moth, Plutella xylostella (Lepidoptera: Yponomeutidae)

N = \sum \left\{ {(n_i + n_{i + 1} ) \times \left( \begin{gathered} census interval between \hfill \\ times i and i + 1 \hfill \\ \end{gathered} \right) \times \tfrac{1}{2}} \right\}

Population dynamics of the green leafhopper, Nephotettix virescens Distant (Hemiptera: Cicadellidae) in synchronized and staggered transplanting areas of paddy fields in Indonesia.

With this method, the role of paddy-inhabiting spiders,Lycosa pseudoannulata, Oedothorax insecticeps, Tetragnatha spp, andEnoplognatha japonica, as predator ofN. cincticeps was evaluated with reference to life tables of the prey. The advantages and limitation of the sight-count method were discussed as compared with other methods so far proposed.

Spatial distribution of three plant bugs in relation to their behavior

An application ofHokyo andKiritanis method (1967) was attempted to estimate the stage specific survival rates of the population with overlapping stages. This method can be written as follows assuming a constant daily survival rate (K) throughout the life: