Almost all ladybugs are beneficial to humans. This comes from their preferred food source of aphids and other harmful soft bodied insects that feed on our vegetables, fruits and flowers. Ladybugs are known to consume large amounts of these pests, making them a gardeners best friend. Now I want to introduce you to one of the exceptions to the rule when it comes to lady beetles. This gorgeous spotted ladybug is the Squash Lady Beetle (Epilachna borealis). Instead of feeding on insects, they feed on cucurbit crops, like squash, melons, and cucumbers. As you can see pictured here, they will use their mouths to cut into the stems of the plants and releasing the tasty juices within. In large enough numbers these beetles could cause significant damage to your garden crops. These beetles will show up on your plants in mid-summer. They mate and lay eggs. It isn't long before the eggs hatch and the young are unleashed on your prized cantaloupe. A curious habitat that the adults possess is to circle a potential feeding site, much like a dog goes in circles before lying down for a nap. It is not fully understood what purpose this serves, but it is cute to watch. In the second picture you can see the damage being done to the leaves by their feeding habits.
The young larvae look like spiny little aliens. They are bright yellow and covered with a spattering of black spiny hairs. They will grow quickly and pupate, then the bright orange and black spotted adults will appear. They are one of the largest lady beetles in Eastern North America where they range. Very little is known about their life cycle, or at least very little is reported on it. My mother had a volunteer pumpkin vine show up in her back yard. She left it to grow because she found the leaves to be interesting and beautiful. It produced one pumpkin and dozens of these beetles, in all stages of development.
How ironic is the 2nd & 3rd pictures, notice the aphids that are present?