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Chang G.,Shaanxi Institute of Zoology | Chang G.,State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture
Chinese Journal of Ecology | Year: 2012

Using Edward's long-tailed rat (Leopoldamys edwardsi), a dominant species in subtropical evergreen broadleaf forests in Dujiangyan City of Sichuan Province, as the experimental animal, a field study with semi-natural enclosure was conducted to examine the effects of several tag-marked methods on the seed dispersal by rats. Among the methods examined, both the marked lines fishing thread and thin steel wire were effective on tracking the seed fates dispersed by rats, but, in considering that the fishing thread was sometimes bitted off by experimental rats, the steel wire was more worthy of application as a kind of perfect marked line. Three kinds of marked tags, i. e., large plastic tag, small plastic tag, and wire tag, did not differ on tracking the seed fates dispersed by rats, but the large plastic tag, due to its large size and strong visibility, was more suitable to be a perfect marked tag for field seed dispersal.

Gang C.,Shaanxi Institute of Zoology | Gang C.,State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture | Kaifeng W.,Shaanxi Institute of Zoology | Zhi W.,Shaanxi Normal University
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2012

Seed dispersal is recognized as a key phase affecting plant regeneration and distribution. By acting as seed dispersal vectors, forest rodents play an essential role in this phase through their scatter hoarding behavior. Although rodents can consume a large number of seeds to meet their immediate energy requirements, they also store some seeds in scatter caches for future use to ensure overwinter survival or reproductive success. Buried seeds are more likely to germinate and survive to the seedling stage if the animal fails to recover some of the seeds; this may occur if, for instance, the animal has died or moved, or stored more than it could use. Pinus armandii, which are common and often dominant tree species in many temperate and subtropical forests, are an important food source for many wild animals. Much attention has been paid to the dispersal biology of Pinus spp.; however, knowledge of the interactions between P. armandii seeds and rodents in Qinling Mountains is still poor. The predation and dispersal of P. armandii seeds by forest rodents were investigated using plastic tags in Foping National Nature Reserve (35°0'N, 105°30'E), located in the southern aspect of Qinling Mountains in Shaanxi Province during September November of 2008 and 2009. Approximately 20 plots (1 m × 1 m), separated by 15 m along a transect line, were established as seed stations in a deciduous broad leaved forest. In September of each year, 50 tagged seeds were placed at each station and seed fates were monitored on 1, 2, 3, 11 and 19 days after initial placement. During each visit, we searched the area around each station (radius < 30 m) for seeds removed by rodents and recorded their fates. The results showed that rodents imposed a strong predation pressure on P. armandii seeds in this study site. In 2008, nearly all the seeds (96. 4%) were consumed by the third day, and almost half of the seeds (49. 6%) were consumed by the third day in 2009. Rodents also played an important role in seed dispersal of P. armandii. In 2009, rodents scatter hoarded 17. 75% seeds by the third day and 12. 25% of hoarded seeds were still alive by day 19. There was a significant difference in seed dispersal of P. armandii between the two years. In 2008, almost all the seeds were consumed by rodents and the quantity of cached seeds was very small. The proportion of cached seeds was significantly greater in 2009 than in 2008. This result may be associated with mast seeding. The yield of P. armandii seeds was very low in 2008 and rodents had to consume a large number of seeds to meet their daily energy needs, leading to a reduction in storage. Whereas the yield of P. armandii seeds was very high in 2009, and there were sufficient seeds to not only meet the daily energy needs of rodents but also to hoard seeds for future use.

Wang Y.,CAS Institute of Zoology | Wang Y.,University of Chinese Academy of Sciences | Watson G.W.,CAS Institute of Zoology | Watson G.W.,Plant Pest Diagnostic Center | And 2 more authors.
Agricultural and Forest Entomology | Year: 2010

1 In recent years, an invasive mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) has attacked cotton (Gossypium hirsutum L.) in Pakistan and India, causing severe economic losses. This polyphagous pest was probably introduced accidentally from North America. Infestations have broken out suddenly and spread rapidly. 2 Seasonal and annual population growth data of P. solenopsis from nine locations in its native range in the U.S.A., and the distribution of the mealybug worldwide, were analyzed using the CLIMEX model. This indicated that tropical regions worldwide were highly suitable for P. solenopsis. 3 Its potential distribution was limited by cold in high latitudes and altitudes, and dryness in northern Africa, inland Australia and parts of the Middle East. CLIMEX was used to predict where P. solenopsis might establish, and to estimate the potential threat to cotton yield in Asia. The key limiting factors were low precipitation as well as minimum temperatures in northern areas. 4 When irrigation was factored into the simulation, the potential distribution of P. solenopsis expanded dramatically, indicating that P. solenopsis presents a great economic threat to cotton in Asia and other parts of the world. © 2010 The Authors. Agricultural and Forest Entomology © 2010 The Royal Entomological Society.

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