POTENTIAL ABILITY OF THE SOLANUM-FEEDING LADYBIRD BEETLE HENOSEPILACHNA DIFFINIS (COLEOPTERA; COCCINELLIDAE) TO USE THE INTRODUCED FABACEOUS PLANT CENTROSEMA MOLLE

Host specificity has been a major factor in generating the tremendous diversity of phytophagous arthropods. Studies of adaptation to introduced or invasive plant species provide an opportunity to investigate incipient evolutionary changes in host specificity. We investigated the cryptic ability of the Asian tropical herbivorous ladybird beetle Henosepilachna diffinis to feed on the fabaceous weed "centro", Centrosema molle , which was introduced to Southeast Asia about 200 years ago. In laboratory choice tests using this plant and the normal host plant, Solanum torvum, adults preferred S. torvum to centro, but over half the beetles tested ate leaves of both plants. Furthermore, most first-instar larvae accepted centro during a rearing experiment, and a few of them grew to the third-instar stage, though none reached the final (fourth) instar. Henosepilachna diffinis likely acquired this incomplete acceptability of centro without any direct host-grazer interaction with centro, probably before this weed was introduced to Southeast Asia. Our results further suggest that another Henosepilachna species , H. vigintioctopunctata , might similarly have already acquired an incomplete ability to use centro when this beetle encountered it for the first time, and this triggered a subsequent host-range expansion from solanaceous plants to include centro in various parts of Southeast Asia. 281 1 7560000 10692000 359410 259 261 257 276 262 279 1 0`````````````````````` 5 1 1 285 282 1 False 0 0 0 0 -1 304800 243 True 128 77 255 3175 3175 70 True True True True True 278 134217728 1 2 -9999996.000000 -9999996.000000 229870 8 Empty 16711680 52479 26367 13421772 16737792 13382502 16777215 Bluebird 22858575 22852950 (`@````````` 266 263 5 110183775 110178150