Insect Developments

Today while collecting along the Consolation Lake Trail at Moraine Lake we came upon some very interesting looking insect. Most people’s first thought when looking at the pictured insect wouldn’t be “Beetle”, but it is indeed the larval stage of a predacious ground beetle.

The young larva of a predacious ground beetle in the family Carabidae

The lifecycle of a butterfly from caterpillar (larva) to chrysalis (pupa) to winged adult is familiar to everyone but some may not know that this lifecycle is not unique among insects and is actually shared by several orders including flies and beetles. When an insect displays this lifecycle pattern they are said to be holometabolous, passing through a distinct developmental change during the pupal stage.

Another developmental strategy seen in the insects involves growth over time without a pupal stage. Orders that employ this strategy are said to be hemimetabolous and include the dragonflies, damselflies, and the true bugs. These insects slowly grow and develop wing buds through multiple molts during the nymphal stage until ready to make the jump to adulthood. After one final molt the adult insect emerges with a fresh set of wings. This is why you can often find the dried remains of dragonfly, damselfly or cicada nymphs gripping a stalk of grass after their final molt.

–          Jon