<- Back To Species Index

Ancestor: Tenebrio molitor (Mealworm Beetle)

Adult Size: Largest species: 40mm long, Smallest species: 9mm long. Larvae are slightly larger than adults and consume calories when they pupate, resulting in an adult of a smaller size. Adults are also denser than larvae, taking up less volume.

Dietary Needs: These beetles do most of their eating as a larva. They eat many things with a high cellulose content, such as dead leaves and dead wood. They prefer wood and leaves that are pre-fermented in the environment by fungi and bacteria. They also consume mycelium and bacterial colonies for added nutrition. Some live plant material may enter their diet such as grains, some living wood, and fallen berries. In the process of eating they boar tunnels through the wood, hence their name.

Adults are slightly more omnivorous and lose their ability to eat tough plant matter, instead occasionally preying on things like gnats and drinking nectar. The mouthparts of adults are weak and they cannot consume enough to sustain repair and nutritional replenishment. They are often too consumed in mating and egg laying to eat much. Adults are usually dead within a month or two of emergence.

Life Cycle: Females lay their 700 eggs in small soil burrows near rotting wood piles, or in organic detritus buildup on the rotting bark itself. The larvae are able to survive in a variety of environments, from high organic soil to deep within chunks of dead wood or the still standing trees that have died, which is preferable to soil. They hatch in early autumn and are quite mobile, but their small size is what makes them so vulnerable. The parents guard the eggs and offspring for the first few days of their life, but that doesn't stop many larger invertebrates such as carnivorous beetles from picking off the larvae before they find safety. The survivors start boring a tunnel with their wide, chipping mouthparts into some wood, bark flakes, fallen leaves or other high cellulose material, which will become their home and they will expand this home as they continue to consume it. They must get themselves in a safe place before winter. They will live in this home for around two years.

Two-year-olds pupate in late spring and emerge in early summer, when the warmth helps energize the insects. Adult males and females congregate into large groups to find a mate. Pheromone signalling is important for males and females to communicate their interest. When a male and female select each other, the male commits to the female. Males will fight each other if they are forced to compete over a female, because if another male mates with her, his sperm will have to compete with that other male's. This is why males will guard his impregnated female until his body loses energy and he dies. Males are slightly flatter, heavier and have "shoulder" spikes (actually part of the thorax carapace) to wrestle and flip over other males with. Males have slightly more flexible head attachment to their body for this so that when they fight they can look straight downward, which moves their head out of the way.

The female's part of the work will be burrowing into the ground and laying her eggs, after which she will become the guard of her eggs. Females last slightly longer than males for this reason but are still usually dead by the end of the summer. They are only needed until the ground around her burrow settles from rain, being walked on, and generally no longer looks so conspicuous.

Other: Adults of this beetle can fly in search of other beetles, as they might not always emerge in a high population concentration. Females will also fly to find a place to lay eggs if there is none suitable nearby.