Science Daily (Apr 27, 2008) — Dutch ecologist Roxina Soler and her colleagues have discovered that subterranean (地下的) and aboveground herbivorous (食草的) insects can communicate with each other by using plants as telephones. Subterranean insects issue chemical warning signals through the leaves of the plant. This way, aboveground insects are warned that the plant is already “occupied”.
Aboveground, leaf-eating insects prefer plants that have not yet been occupied by subterranean root-eating insects. Subterranean insects send out chemical signals through the leaves of the plant, which warn the aboveground insects about their presence. This messaging makes it possible for spatially-separated insects to avoid each other, so that they do not compete for the same plant.
In recent years it has been discovered that different types of aboveground insects develop slowly if they feed on plants that also have subterranean residents and vice versa (反之亦然). It seems that a system has developed through natural selection, which helps the subterranean and aboveground insects to notice each other. This avoids unnecessary competition.
Through the “green telephone lines”, subterranean insects can also communicate with a third party, namely the natural enemy of caterpillars (毛虫). Parasitic wasps (寄生的黄蜂) lay their eggs inside aboveground insects. The wasps also benefit from the signals sent by the leaves, as these help them find more insects for their eggs.
The communication between subterranean and aboveground insects has only been studied in a few cases. It is still not clear how widespread this phenomenon is. But scientists are looking into it. This research was carried out at the Netherlands Institute for Ecology (NIOO-KNAW) by Roxina Soler, Jeffrey Harvey, Martijn Bezemer, Wim van der Putten and Louise Vet. The PhD project, in which this study was carried out, was funded by the Free Competition of NWO Earth and Life Sciences.
51. After finding a plant occupied by subterranean insects, aboveground insects usually ____.
A. send out warning signals             B. choose to give up the plant
C. compete for the plant               D. share it with the subterranean insects
52. Aboveground insects will develop more quickly if they ____.
A. feed on plants occupied by subterranean insects
B. feed on plants not occupied by subterranean insects
C. become cleverer through natural selection
D. compete with subterranean insects
53. Subterranean insects communicate with a third party through ____.
A. caterpillars     B. parasitic wasps    C. wasps’ eggs    D. a plant’s leaves
54. What can be inferred from the last paragraph?
A. Other animals may communicate in the same way.
B. There will be further research into this phenomenon.
C. Part of the study is a PhD project.
D. The Free Completion of NWO Earth and Life Sciences has the patent for these results.
55. What would be the best title for this passage?
A. Insects use plants as a telephone.         B. Insects live in harmony with each other.
C. No species can live alone.               D. Plants and animals have an effect on each other.