Elasmucha grisea Insect Awl Shield Stink Bug Hemipterus Rhynchota Heteroptera Pentatomid

 mm 8-12 Insect Awl Shield Stink Bug Hemipterus Rhynchota Heteroptera Pentatomid.
Family: Pentatomidae or Acanthosomatidae.
Common name: Parent Bug.
Syn: Cimex betulae, Elasmucha interstinctum.

Elasmucha grisea (Linnaeus, 1758), is a heteropterous rhinchote insect of the Acanthosomatidae family. An adult specimen reaches a length of 8-12 millimeters.
The livery can have different colours: the typical specimen is grey, but there are also specimens with reddish-brown and brownish-green livery. The upper part is covered with numerous darker dots while on the lower part the only darker parts are the tracheae. In autumn the livery darkens and tends to red-brown. The lateral edges of the posterior part of the body (Connexivum) are sometimes light and dark.
They are phytophagous insects, which feed essentially on the leaves and flowers of birch trees (Betula pubescens, Betula pendula) and alders.
After mating, the female lays 30 to 50 eggs on the underside of a leaf and remains near the eggs to defend them from possible attacks by predators and parasites, until they hatch, which generally occurs after 10-15 days. The female continues to care for the young larvae for several weeks, a relatively rare behavior in the world of insects (but common to several species of Acanthosomatids). For this reason its common English name is parent bug. To defend them from potential predators (ants, spiders, beetles and other insects) it uses various techniques: in most cases it simply places itself between its larvae and the potential threat. When this is not enough, it takes on a more aggressive attitude, opening and flapping its wings and finally emits a noxious liquid, capable of paralyzing the attacker.
Shortly after hatching, the young larvae moult for the first time and adopt a green and black colored livery. In this stage the nymphs continue to move in groups and acquire the ability to expel a noxious liquid if attacked. The liquid acts like a pheromone and recalls the mother to the place of danger; it can also be used as an odorous trail to guide nymph colonies in moving from one part of the host plant to another.
They are cosmopolitan insects whose diffusion follows that of the Betulaceae: they are common in the areas where these trees grow, absent elsewhere.