Nothofagus produces heavy crops of seed infrequently, and then house mouse (Mus musculus) populations increase greatly. In the Orongorongo Valley, near Wellington, seedfall of hard beech (Nothofagus truncata) and the numbers of house mice were measured for 22 years. Four heavy seedings were recorded and the numbers of mice were significantly correlated with the beech seedfall. Most mouse stomachs contained remains of arthropods, especially caterpillars and spiders, as well as plant material. Moths emerging from the litter of the forest floor in summer were sampled for seven years; the numbers of Tingena epimylia (Oecophoridae), whose larvae are litter-feeders, were strongly correlated with beech seedfall. The correlation between the numbers of moths and mice was slightly stronger than that between the numbers of beech seed and mice. Because the numbers of T. epimylia varied so greatly, components of the litterfall were also measured for three years. In a seeding year spent male flowers were a substantial part of the litterfall and might be responsible for the higher numbers of moths. These results indicate that factors other than quantity of seed may be important in the beech seed -mouse relationship and need to be explored further.

The abundance and seasonality of invertebrates were studied in 3 forest communities near Wellington, New Zealand by pitfall trapping at equal intensity for 14 months. Of 238 species trapped (93 461 individuals), 172 (50 204) occurred in mixed broadleaf-podocarp, 98 (23 072) in hard beech (Nothofagus truncata), and 107 (20 185) in silver beech (Nothofagus menziesil) forest. The composition of the invertebrate fauna differed amongst forest communities. Although many invertebrates were active throughout the year, significantly more were caught in autumn, and fewest in winter. The temporal distribution of several species was correlated positively with temperature, but very few species showed a correlation with rainfall. More species and individuals occurred in the more botanically diverse broadleaf-podocarp forest than in the beech forests. Species composition was more diverse in the lowland broadleaf-podocarp forest than in the high-altitude silver beech forest.

Browsing damage caused by opossums (Trickosurus vulpecula) was assessed visually, against a simple index, on 24 northern rata trees (Metrosideros robusta A. Cunn.) every 2 months from November 1969 to November 1974. All 24 trees showed some damage, and 3 died as a result of continued heavy browsing; 7 of 26 other rata trees in the study area have died similarly since 1969. When opossums were excluded from 5 previously browsed trees, all recovered. Stick insects (Phasmatidae) contributed about 3% to the total damage, but with other defoliating insects may be more important in other parts of New Zealand.

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