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Most of us recognize the life stages of butterflies, but what about beetles?


scarab-beetle-grub-100For example, would you know this larva would turn into a beetle?

scarab-beetle-grub-200Although the head capsule may look a bit like a caterpillar, this is a beetle larva commonly called a white grub. It lives in the soil and will turn into a type of scarab beetles called a "June beetle."


Here's an odd one. I found this in a mesquite seed pod. It is about the size of a small grain of rice.

seed-beetle-pupa-100Turning it over, it has two dark spots, which are the developing eyes. This is the pupal stage of a seed beetle or bruchid.


The seed beetles lay their eggs on seeds of legumes like mesquites, within the seed pod. Can you see the white eggs that look like sesame seeds attached to the larger brown mesquite seeds?

The larvae, which look like small versions of the white grub above, feed inside the seeds and then cut their way out to pupate. You can see the holes in the seeds and the round caps on the left of the photograph where the larvae cut their way out.


Soon the seed beetle pupa will become an adult like this one and go look for a place to lay its eggs.

Have you ever found beetle immatures before? Where did you find them?




Last week we looked at the life cycle of grasshoppers, now we are going to find out more about seed beetles.

We have often seen seed beetles feeding on pollen and nectar from flowers. Where do they come from?

We had picked up some seeds for our regular "seed of the week" feature, and put them in a vial. When the time came to take the photographs, we discovered we had collected more than seeds.

The vial was full of tiny seed beetles (a different species than above).

You can see where the beetles had emerged from the neat round holes in the reddish-brown seeds. What are the light-colored things that look like sesame seeds on the surface?

Those are the eggs of the seed beetles. Because they were trapped in the vial, the adults were laying eggs on the seeds they had emerged from. The eggs will hatch into larvae that will tunnel back into the seeds. After feeding. molting and growing, the larvae will pupate. The pupa then transforms into the adult beetle. The adults cut through to the outside of the seed to continue the cycle.

Can you see the neat round caps the beetle cut from the seed coats on the ground to the left? Those few seeds produced quite a few beetles. Most had two exit holes per seed.

Imagine being small enough to complete your life cycle within a single seed!