Population and community level comparisons of canopy-dwelling non-target arthropods in hybrid transgenic Bt and non-Bt eggplant in four multi-location trial sites in the Philippines

Issue Date

10-2013

Abstract

Comparison of canopy-dwelling non-target arthropods on hybrid transgenic Bt and non-Bt eggplant in four multi-location trial sites (Laguna, Pangasinan, Camarines Sur and North Cotabato) using redundancy analyses (RDA) at population level, principal response curve (PRC) at the community level was done. Biplot diagrams of the ordination results from RDA from each site were generated using CanoDraw for Windows v4.13. PRC analyses of repeated measures to test and display treatment effects that change across time at the community level were done using CANOCO for Windows v4.5. Significance was tested using the unrestricted Monte-Carlo method (499 permutations under reduced model). Other ecological parameters such as Shannon-Weiner diversity index. evenness, rare faction analyses for species richness and Spearmanns rank abudance correlation between crop types were also used. RDA analysis showed that leafhopper Amrascabiguttula and whitefly Bemisiatabaci were the highly dominant species in Laguna and Pangasinan and showed negative interaction but not in the other two sites. Some species like the lepidopteran leafminer Phycitaclientella and semilooper. Chrysodeixiseriosoma, were consistently associated strongly with non-Bt eggplant. Other arthropods did not show clear trends in terms of preferential association with a particular crop type. However, except in the second cropping season for Laguna, no significant differences in arthropod communities across sites were detected by PRC. Variance explained by sampling period ranged from 23.4 to 56.3% while variance explained by crop type were low, ranging from 4.2 to 8.5% except at 26.0% in the second cropping season for Laguna that was traced to very high population of P. clientella on the non-Bt compared to Bt-eggplant. Arthropod diversity and evenness were not different between crop types and were highest in North Cotabato, followed by Camarines Sur. Species richness was also highest in North Cotabato but lowest in Camarines Sur. Spearmanns rank abundance correlation between crop types were very high at 99.99% in all sites.

Source or Periodical Title

The Philippine Entomologist

ISSN

0048-3753

Volume

27

Issue

2

Page

204

Document Type

Article

Frequency

semi-annually

Language

English

En – AGROVOC descriptors

AMRASCA BIGUTTULA; BEMISIA TABACI; ARTHROPODA; EGGPLANTS; BACILLUS THURINGIENSIS; CANOPY; HYBRIDS; HYBRIDIZATION; PHILIPPINES

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