Nature on out doorsteps; Autumn Shield Bugs
Rosaleen Dwyer is the County Heritage Officer at South Dublin County Council – every week she gives us an insight into nature on our doorsteps and the beautiful biodiversity of its plants and wildlife.
On sunny autumn days, insects that are still around will take advantage of the late-season warmth by basking on bushes and Brambles, particularly in sheltered places out of the wind.
Shield Bugs can often be found sun-bathing like this.
These recently matured adults developed from eggs that were laid earlier in the year.
They will survive winter by hiding in fallen leaves and grassy tussocks, and they will emerge next spring to mate and lay eggs.
Shield Bugs are named for the shield-like shape of their bodies.
Ireland has about 16 different species, and while most are combinations of greens and brown, some can be more colourful.
Their relatively large, robust bodies might suggest that they are beetles, but there are a number of differences between these insect types.
A beetle’s wings are hard and shiny and meet in the middle of its back, forming a clear straight line.
The Green Shield Bug can sometimes occur in small groups of mixed generations
With Shield Bugs, the bottom third of their wings are soft and membranous, and these overlap to form a different coloured spot at the tip of the insect’s body.
Shield Bugs are also referred to as being ‘true bugs’.
This term refers to a large grouping of insects that do not have biting or chewing mouthparts.
Instead, they have long flexible tubes (or beaks) with a sharp point which they use to pierce and suck juices from plants and other prey.
True Bugs, like the Shield Bug, also differ from most other insects in that they only have three stages to their life cycle.
Instead of going through the egg, caterpillar, chrysalis or pupa, and adult stages like other insects, True Bugs progress from the egg to a nymph phase, and then directly to the adult stage.
As a nymph, the Shield Bug’s body is more rounded in shape, and its wings have not yet fully developed.
They will grow and shed their skins a number of times before they finally reach the adult insect stage.
So, while all True Bugs are indeed insects, not all insects are True Bugs!