快猫短视频

SPIDERS scare off insects and help plants boost seed production in exchange
for dollops of sugary nectar, say scientists in New Jersey.

Many species of plant produce enticing nectar bonuses known as extrafloral
nectaries (EFNs). The EFNs attract ants which defend the plant against
leaf-eating insects in return for the sweet treats. Some tropical tree species
can die without the ants鈥� protection.

Only a few spiders are known to take an interest in EFNs. To find out more,
Steven Handel and Scott Ruhren from the State University of New Jersey in New
Brunswick studied the interactions between jumping spiders from the genera
Erisand Metaphidippus, and a yellow-flowered legume (
Chamaecrista nictitans) common to the eastern US.

Greenhouse experiments showed the spiders jumped onto plants with active EFNs
six times more often than those without, and regularly ate the extra nectar. The
plants also benefited from the spiders鈥� presence in the field, where seed
production rose by 8 per cent (Oecologia, vol 119, p 227). 鈥淭his is the
first evidence that spiders can increase plants鈥� fitness in terms of seed
production,鈥� says Handel. 鈥淚t鈥檚 a completely unexpected link in nature.鈥�

Most spiders sit and wait for their prey, says Handel, but jumping spiders
move around and are aggressive鈥攋ust like the ants that protect trees.
Handel suspects the spiders play as vital a role as ants in protecting plants.
鈥淢ost people hate spiders. Now there is finally one reason to like them,鈥� he
says.