''Pterinoxylus spinulosus'' is a species of
stick insect found in the
Neotropics
The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone.
Definition
In bioge ...
. It was
first described by the Austrian entomologist
Ludwig Redtenbacher
Ludwig Redtenbacher (June 10, 1814 in Kirchdorf an der Krems, Austrian Empire, Austria – February 8, 1876 in Vienna) was an Austrian doctor and entomologist mainly interested in beetles. He was the brother of the chemist Josef Redtenbacher (chem ...
in 1908, from an adult male and an immature female. It was not until 1957 that an adult female was described by J.A.G. Rehn.
Description
This species is
sexually dimorphic
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
. The male is slender and elongated with large wings which are normally kept closely folded, while the female is larger and more robust, but with smaller wings. Both sexes are some shade of greyish-brown or dull brown, and the female sometimes has pale, lichen-like markings. When in the resting attitude by day, the insects resemble pieces of twig and are difficult to distinguish from the surroundings.
[
]
Ecology
Like other stick insects, ''Pterinoxylus spinulosus'' is a herbivore,[ It has several modes of defence against ]predation
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
. The first is crypsis; the insect is nocturnal in its habits and both adults and nymphs spend the day stationary in a resting position with the front legs extended forward beside the head and the other two pairs of legs folded tightly to resemble side twigs on a dead stick. This arrangement of limbs conceals the head and may deceive a visually-hunting predator so that the insect remains unnoticed.[
However if disturbed by being touched, the insects raise their wings sharply. The male holds its wings and ]tegmina
A tegmen (plural: ''tegmina'') designates the modified leathery front wing on an insect particularly in the orders Dermaptera ( earwigs), Orthoptera (grasshoppers, crickets and similar families), Mantodea (praying mantis), Phasmatodea (stick an ...
(leathery front wings) vertically and this has the effect of making the insect appear larger. It may maintain this position for a minute or more and then snap the wings shut. If further disturbed it may repeat these actions, or it may fly off. Under similar circumstances, the female raises its tegmina vertically and extends its wings laterally. This exposes the bright red underside of the tegmina in a "startle" display. The wings are translucent and dark brown, with black venation, and produce metallic reflections in sunlight. While holding the tegmina open, the wings move rapidly forwards and backwards, rubbing against the tegmina and producing a stridulatory sound. This sound has been described as being like that produced by a bumblebee
A bumblebee (or bumble bee, bumble-bee, or humble-bee) is any of over 250 species in the genus ''Bombus'', part of Apidae, one of the bee families. This genus is the only extant group in the tribe Bombini, though a few extinct related genera ...
or a distant aircraft.[
]
References
{{Taxonbar, from=Q10645472
Phasmatodea
Insects described in 1908