How moths tell if a yucca's a virgin.
Brushing flowers with substances from female abdomens tricked moths into reacting as if the bloom had already been visited, report Chad J. Huth and Olle Pellmyr of Vanderbilt University in Nashville in the June OECOLOGIA.
These latecomers waggle their antennae furiously as if checking for scents. If one or more moths have already found the same flower, the late visitor reduces the number of eggs she lays there or just departs.
Huth and Pellmyr also observed that females crawling around a blossom make a characteristic gesture that looks like scent smearing, dragging their abdomens over the flower surface.
Yuccas and yucca moths need each other. During a female's few days of adult life, she cruises for yucca blooms, the only place she deposits her 100 or so eggs. When she finds a likely flower, she injects three to five eggs into the flower's ovary, and in most cases, pollinates the flower too. This is the only pollination service the flower gets, Pellmyr explains.
When an egg hatches, the developing larva eats about 20 of the yucca flower's 300 seeds. If too many larvae hatch in the same flower, however, the plant aborts it, and the larvae die. The moths therefore face a strong evolutionary pressure not to overload a flower, says Pellmyr.
Other insects leave perfume calling cards, such as Heliconius butterflies scenting the leaves on which they lay eggs. The new analysis, Pellmyr says, is the most direct evidence that yucca moths also leave their marks.
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|Title Annotation:||yucca moths|
|Article Type:||Brief Article|
|Date:||Jul 3, 1999|
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