''Herennia multipuncta'', commonly known as the ornamental tree trunk spider, is a species of spider in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Araneidae native to Asia. It exhibits

sexual dimorphism 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 an ...

, the female being much larger than the male. It weaves a small web on the trunk of a tree or the wall of a building and is well

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

d by its dappled colouration.

Description

The female has a hairy cephalothorax that is narrow in front and longer than it is wide. It is reddish-brown with a yellowish, U-shaped patch near the front and darker markings further back. The mouthparts are yellowish-brown and the long, slender, hairy and spiny legs are mostly brown. The abdomen has a flattened, pale grey dorsal surface with five pairs of sigilla (puncture-like spots where muscles are attached internally), numerous grey specks and a few dark streaks near the back. The male is reddish-brown with dark legs. His body length at is about half that of the female at . This spider rests head-downwards on the web with its legs flexed. Its colouring makes it well camouflaged.

Distribution and habitat

''H. multipuncta'' is found in tropical parts of southern Asia where its range includes India, Malaysia, China and New Guinea. It is often found in association with man and has spread to other countries where it is considered invasive. Its habitat is the trunks of trees and the walls of buildings where it creates a small web close to the surface. The web starts off as an orb web using prominences on the underlying structure for support. As the spider grows, so does the web and allometrically becomes a substrate-dependent ladder web with parallel-sided rather than rounded side frames. The hub of the web is modified into a silken cup. This species is said to be invasive and

synanthropic A synanthrope (from the Greek σύν ''syn'', "together with" + ἄνθρωπος ''anthropos'', "man") is a member of a species of wild animal or plant that lives near, and benefits from, an association with human beings and the somewhat artific ...

Behaviour

Like other spiders, the male of this species uses his

pedipalp Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") an ...

s to insert sperm into the female's seminal receptacles. The terminal joint of the palps become detached and remains in the female during seventy-five to eighty percent of matings, especially when the female is aggressive. It is surmised that the severed copulatory organs may function as plugs to prevent leakage of sperm and that abandoning them may be a sensible option for the male as otherwise his damaged palps might leak

haemolymph Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which ...

. Although their loss effectively makes the male sterile, he usually stays with the female and fends off rival males, and this behaviour protects his reproductive investment. A subsequent study suggests that losing the extra weight of the pedipalps allows males to more effectively fend off rival males, guard their mate and thereby ensure paternity.

References

{{Taxonbar, from=Q1906437 Araneidae Spiders described in 1859 Taxa named by Carl Ludwig Doleschall Spiders of Asia