The Stag Beetle is the largest beetle in the Donau-Auen National Park – and in all of Europe! There is a significant difference between males and females: the males have oversized "antlers" (like stags) which are really enlarged jaws, whereas the females are smaller overall and also much have smaller jaws without the "antlers".
Description
Males reach up to 90mm and females 50mm. The male can be recognized by its broad head and large reddish-brown jaws, the antlers. The female has a narrower head without the enlarged mandibles. Elytra are medium to dark brown. Stag beetles are able fliers.
Distribution
Found in the warmer parts of Central, Eastern and Southern Europe where there are oak trees. Period in which they fly is from the end of May to June/July; during this time, Stag Beetles may be found nearly everywhere in the National Park, but above all in the hardwood riparian forests in the vicinity of old oaks.
Endangerment and Conservation Status
Although this beetle is not rare in the National Park, it is potentially endangered in Austria. The Stag Beetle is in decline only because forestry operations habitually remove the essential element of their habitat: dead and rotting trees.
Behaviour
Stag Beetles fly most often at dusk in the vicinity of oak trees. With their brush-shaped lower lips they suck the sap from holes or cuts in trees. Females make little holes in the bark of twigs and branches with their tough short teeth then lick up the sap running out. Males actually depend on females to "prep" the trees for them should they not be able to find any natural wounds which exude sap. Males attract females by spraying their droppings. Should more than one male approach a female simultaneously – for example on a branch – there may be a battle for the female: like their namesakes, Stag Beetles lock antlers, raise each other up, each attempting to throw the other from the branch. Serious injuries rarely result from these fights, although the beetles may puncture their shells. The winner remains with the female, whom he then covers, and proceeds to lick the oak sap with its long tongue. Both feeding places and females will be defended against other individuals. Larvae are called grubs. They normally mature in old, rotting oak wood and much less often, beech; they are around 10cm long and require 5-8 years (!) to become pupae. The pupae case is about the size of a fist and is hidden in the ground, whereby the male's is larger than the female's. Animals which find less suitable nourishment during the larval stage are normally smaller than other mature beetles, and males may have smaller antlers.
Special Characteristics
During their flight season, one may often find the head and upper body of males on hiking paths. Warning: thanks to their special insect nervous system, these body parts may remain active many hours – up to 48 – and can even inflict a painful bite on a human! It is best to pick up these animals by the abdomen. Whether these "dead" yet still moving animals can feel pain has not yet been fully determined. The sensory and experiential world of an insect cannot be compared to that of vertebrates. These large beetles are preyed upon by woodpeckers, who however scorn the head and horny parts which are thrown unceremoniously to the ground. Thanks to its size and reddish jaws, the Stag Beetle has inspired many highly-descriptive names: Billywitch, Cherry-Eaters, Devil's Beetle, Horny Bug, and Thunder Beetle. In the olden days, the superstition used to prevail that male Stag Beetles carried fire in their (red) jaws while flying through the woods.