The spatial pattern of Kytorhinus immixtus and its response to desert landscape pattern in Ningxia
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Key Words： Kytorhinus immixtus, spatial distribution pattern, aggregation indices, damage ratio, desert landscape pattern
Abstract： Kytorhinus immixtus Motschuleky is a seed pest of Caragana. Using some aggregation indices,and the Iwao and Taylor regression analysis methods, the spatial distribution patterns of egg and larvae,and the damage ratio of K. immixtus in 11 desert landscape patches in Ningxia, were surveyed and analyzed. The results show that the spatial distribution K. immixtus was aggregated and approximated a negative binomial distribution. The Iwao model of egg and larvae of K. immixtus were m*=2.23695+1.64742m(r=0.8273) and m*=2.24418+1.42084m (r=0.8889), and the Taylor’s power model of egg and larvae of K. immixtus were logS2=0.51292+1.41118logm(r=0.9344) and logS2=0.59645+1.14736logm(r=0.9786). The basic component of distribution was individual population. Analysis based on estimation of the mean aggregation (λ) suggests that this aggregation landscape pattern and interspecific competition. The aggregation intensity increased with density of population. The regression analysis showed that it is not significantly a correlation between patch area and damage ration of K. immixtus (R2=0.1995) in desert landscape. A principal components analysis showed that the soil type, and survival of Caragana were major factors affecting the damage ration of K. immixtus.