University of Kentucky Department of Entomology

Mystery Bug Answers

Mystery Picture #43

Mystery Picture #43

R. Bessin, University of Kentucky
copyright, University of Florida Entomology,
used with permission
(Mystery Pictures)(Mystery Pictures)


There are two different types of insect in this month's mystery picture. The black Ants are very common insects that prefer to live in large groups where members are specialized for different tasks. You have probably seen them foraging for food in your backyard, on the sidewalk, or even in your kitchen!

The soft-bodied green Aphids in the picture have long thin mouthparts that they use to suck juice from plants. They can be be a serious pest in the garden.

Bonus questions:

What is the relationship between these two insect species?

Answer: These ants and aphids have a mutualistic relationship -- they each derive some benefit from their association: the ants obtain honeydew, a sugary secretion made by the aphids, to eat, and the aphids are protected from predators by the aggressive ants.

Why are they often found together as seen in this picture?

Answer: Some species of ants are "aphid farmers" -- they tend aphids in a way similar to human farmers tending livestock. The ants protect the aphids from predators by patrolling the area where the aphids are feeding; if they encounter other insects, they sting or bite them until they leave or fall off the branch. As the aphids feed, they suck the plant juices out of the plant leaves and stems. Eventually, the plant wilts and the juice no longer flows. The ants will then pick up the aphids and carry them to a new juicy stem where they can continue to feed and produce the honeydew that the ants eat. At night, the ants will often carry the aphids to a safe place for the night and bring them back to a plant to feed in the morning!

How might this affect your garden?

Answer: If the ants think your vegetables look juicy and tasty, they will bring their aphids into your garden to let them feed. Pretty soon, your plants will be wilted and dying. Also, the honeydew the aphids secrete is very sweet and sticky and quickly becomes covered with messy molds and mildew.

An interesting fact: For most of the year, almost the entire population of each of these insects is made up of only one sex (male/female). Which sex is it?

Answer: Female

To read more about aphids, see EntFact 103 -- Those Pesky Aphids!


This is the immature stage of a Mosquito, also sometimes called a "wiggler" because of its distinctive wiggling motion when it swims through the water. Mosquito larvae are aquatic insects, but after undergoing the pupa stage (which floats near the water surface), the new adult emerges into the air and flies away to live a terrestrial life. Adult female mosquitos feed on blood which is necessary to allow them to make eggs. Adult males usually feed on flower nectar. Mosquitoes are a health concern because as they bite their victims, they can spread diseases such as encephalitis and malaria. Dog heartworm can be transmitted by the bite of the adults as well. Mosquito larvae can be found wherever there is standing water, including ponds, drainage ditches, in tin cans, old tires, buckets or any container that can hold water.

See EntFact 005 - Kentucky Mosquitoes and Their Control for more information on mosquito biology and control.

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