Most mating plugs in other animals are typically viewed as a male tactic used to increase his chances of paternity, without participation of the female.

A second special feature of L. mariana is the possible relation between the undiminished behavioral capabilities of the tiny spiderlings that have only recently emerged from the egg sac; design modifications of the spiderling’s nervous system (greater relative brain size and reduced neuron size) result in it having similar estimated numbers of neurons to those of adults.

This may explain the lack of behavioral deficits in web construction by the spiderlings compared with adults.

On the other hand, predators and prey looking up at the spider from below would see the silvery white pattern, which may also provide camouflage against clouds and the bright sky.

The red markings may also serve as a warning to possible predators, as L. mariana emit a weak repugnant odor that can be sensed when a spider is held in the fingers very close to the nose.

The first  Leucauge specimens were discovered by Charles Darwin in 1832 near the Guandu River (Rio de Janeiro) and the genus was originally described  by Adam White in 1841.

Several aspects of the sexual behavior, including sexual cannibalism by the female, frequency of mating plug formation, and correlations between male behavior with plug formation differed in comparisons of specimens of L. mariana from Costa Rica with others from Colombia; it is thus not certain they are the same species.

[3] In the Valle Central in Costa Rica the spiders are very common among weeds in early secondary growth and along wooded streams.

Before the arrival of humans, secondary vegetation of this sort grew near rivers, landslides and tree-fall gaps.

[6] Field-caught males and females can live for a week or longer in captivity without additional food if they are kept in a humid environment.

After preliminary threats by jerking the web, males spread their front legs as they come together, probably measuring each other’s size.

Typically the winner cuts the line that the loser leaves behind, thus breaking his contact with the female’s web.

Genital coupling occurred when the male extended one of his pedipalps to make contact with the female's abdomen and attempts to insert it into her epigynum.

Insemination occurs early during copulation  when the sperm is transferred by the embolus into chamber I of the female’s spermatheca.

[8] For a mating plug form the female must add a liquid that combines with the male’s material to create a smooth-surfaced mass that, when it hardens, adheres tightly to the epigynum and blocks the entrance to the insemination duct.

Female choice of sexually successful males was associated with involved strength of cheliceral clasping, duration of palpal insertion, and sperm count (measured through hematodocal inflation rates).

During the dry season, however, adults sometimes form aggregations in which their orb webs are built on shared tangles of support silk strands.

Often a spider builds several orbs each day; the first 1 to 2 hours before dawn, another around noon, and still another early in the evening.

[15] L. mariana often reuse the frame lines of previous webs when building a new orb at the same site.

[16] When she begins an orb, a spider can adjust several aspects of the design of an orb (including the total area, the number of radii, and the spaces between sticky and non-sticky spiral lines) to the amount of sticky silk that she has available in her silk glands.

Again, these feats are accomplished even though the spider cannot see the lines in her web and must rely on touch to sense them.

Spiders waiting at the hub responded (with no preliminary warning) to the impact of a prey on her web by turning up to greater than 90o, locating new lines to grasp for all eight legs, determining the location of the prey, and ran 4-5 body lengths to attack, all in as little as 0.21s.