When Caterpillars Attack, Tobacco Plants Use Their Own Spit Against Them

If you’re a tobacco hornworm caterpillar, your own spit can come back to bite you: That plant you tried to eat for dinner can use your own saliva to summon larger animals that might like to make you their dinner.

According to a study in Science, the tobacco plant has evolved a clever defense against hungry insects—it calls in the insects’ predators for help:

When a leaf is wounded, plants immediately release a “bouquet” of distress chemicals known as green leaf volatiles (GLVs) into the air. GLVs are formed when long fatty acid chains in the cell membranes are chopped up into six-carbon molecules as a result of damage. These molecules can exist in two different shapes, or isomers, depending on the position of a double bond between two of the carbons [The Scientist].

What’s cool, though, is that the tobacco plant gets personal when it’s being devoured. Ian Baldwin and colleagues found that the plant gives off a different set of GLVs when it’s damaged by a caterpillar than when it’s damaged in other ways. The plant’s chemicals, Baldwin says, seem to react with those in the caterpillar’s saliva to create a signal that captures the attention of the caterpillar’s predators.

source: discover magazine

Bees dances to communicate

Bees first let other bees taste the small bit of nectar it collected from the flower.

Dancing bees talks to the bees around it by moving its body in a specific way.The direction and speed of the bee’s movement communicates location of the food to other bees

one such move is making rapid circuit of around two seconds per circuit which means food source is 200 meters away

The angle of the bee’s body when she waggles gives the direction of the food. If the bee waggles with her head pointing 90 degrees to the right, the the food source is 90 degrees to the right of the position of the overhead sun

if it dances in a straight line towards the upper part of the hive, then source of nutrients are exactly in the direction of the sun. If its in opposite direction, then it makes moves in a line pointing downward direction.

It also calculates sun’s movement (which is 1 degree every 4 minutes).

A new study used an established method for altering a honey bee’s perception of distance as she flew through a tunnel to gather food. Vertical stripes or a busy pattern on the tunnel walls can trick a bee into thinking she is traveling a greater distance, while horizontal stripes or a sparse pattern indicate a shorter distance — even though the tunnels are the exact same length. At the end of the flight, a researcher watches the honey bee dance to find out how far she thinks she flew.