The possibility of sustainable pest management by introducing bio-diversity: simulations of pest mite outbreak and regulation

Abstract

Since the late 1980s, spider mite pests have caused serious damage to many moso bamboo (Phyllostachys pubescens) forests in China's Fujian province. The culms of this plant are an essential component of the building and handicraft industries, and the shoots are a prized food item in many Asian countries. Furthermore, bamboo forests play an important soil conservation role in mountainous areas. We examined pest mite outbreaks in several moso bamboo plantations in Fujian, and could show that a change in cultivation style from polyculture (a kind of mixed forest) to monoculture (all plants other than bamboo were removed) was primarily responsible for the local extinction of an important predaceous mite species. This phenomenon is due to the periodic shedding of leaves by the bamboo, which forces the predator mites occurring on bamboo to switch to prey mite species that occur on other plants. We then tried to elucidate the factors that resulted from such a cultivation change. Adopting a computer simulation approach, we could successfully show that at least two plants, moso bamboo and Chinese silvergrass, are necessary to maintain stable predator-prey interactions in moso forests. That is, systems consisting of one common predator and two host-specific pest mites on different host plant species frequently became stable when the pest mites were at low density. This finding indicates clearly that bio-diversity, even when it consists of only two plants and three mite species as in this study, is necessary for the sustainable regulation of large-scale forests, such as moso bamboo plantations.

Variation in counterattack effect against a phytoseiid predator between two forms of the social spider mite, Stigmaeopsis miscanthi

“…The phytoseiid mite T. bambusae (known to be an important predator of S. miscanthi in China; Tsuji et al 2011) used in this study was collected on 10 May 2003 from S. longus nests on Sasa senanensis (Franch. et Sav.…”

Locking out predators by silk, a new counterattack behaviour in a social spider mite

“…The Sn counterattacks would be more efficient if both Sn mothers and fathers defended their nest together, as happens with S. longus (biparental defence in Saito, 1986b). However, Tb is able to maintain its status as the main predator of Sn populations (Zhang, 2002;Tsuji et al, 2011). We showed three types of behaviour (ripping dense nests, excluding Sn adults and killing them) for managing counterattack efforts by Sn adults.…”

“…It is the sole regulator of S. nanjingensis on Moso bamboo in China (Zhang, 2002;Tsuji et al, 2011) and of S. longus on Sasa dwarf bamboo in Japan (Takahashi, 1987). If predators cannot effectively overcome the counterattacking efforts of their prey, they will either become extinct or switch their preferences to other prey species.…”

“…Despite the strong counterattack behaviour of its prey, T. bambusae remains an important predator species of S. nanjingensis. It is the sole regulator of S. nanjingensis on Moso bamboo in China (Zhang, 2002;Tsuji et al, 2011) and of S. longus on Sasa dwarf bamboo in Japan (Takahashi, 1987). As such, resolving the question of how T. bambusae maintains its predator status under complex predator-prey interactions in nature is very important.…”

Assessing impacts of forest conversion on terrestrial vertebrates combining forestry cost with HSI and InVEST: case of Toyota city, Japan

“…Among these, mixed forest management has been promoted as a solution to issues pertaining to forest productivity (Perot & Picard 2012), resistance to pests and diseases (Riihimaki et al 2005;Koricheva et al 2006;Tsuji et al 2011), biodiversity conservation (Mielikäinen & Hynynen 2003), plant species richness (Ramovs & Roberts 2003), bird species richness (Jansson & Andrén 2003), diverse wildlife habitat (MacDonald & Thompson 2003) and enhancement of multiple ecosystem services (Gamfeldt et al 2013). …”