Maevia inclemens

Like all jumping spiders, M. inclemens has excellent vision. The main eyes, in the front-and-center position, are large, and are more acute than those of a cat and about 10 times as acute as a dragonfly's. The remaining three pairs of eyes are along the sides of the head, and work as motion detectors. The eyes are used for hunting, for avoiding threats and for finding mates.

Maevia inclemens is one of the eight species in genus Maevia.^[3] The species was first called Attus inclemens, and other names have been used. The two male forms look and behave so differently that they were originally considered two distinct species. In 1955 Robert Barnes chose M. inclemens,^[2]: 1 and this has become the standard name.^[3]

The species is found in south-eastern Canada, and in the eastern United States. M. inclemens is frequently seen on man-made structures such as outbuildings or fences.

Taxonomy

Maevia inclemens is the type species for the genus Maevia (C.L. Koch, 1850), ^[2]: 2-3 which includes another 10 species in May 2011.^[3] The species name is derived from Latin adjective inclēmens "cruel, harsh" or "rough".^[4] The species was first called Attus inclemens, and other names including Attus vittatus, Maevia pencillata, and Maevia vittata.^{[a][2]: 2-3} Also the two male forms look and behave so differently that they were originally considered two distinct species.^[5] In 1955 Robert Barnes chose M. inclemens,^[2]: 1 and this has become the standard name.^[3]

Description

Spiders are

In spiders and other

Spiders groom themselves regularly, and more often if wet or dirty. They moisten their fangs, draw the legs one at a time through the fangs, and "comb" the legs with the fangs and palps. The first and fourth pairs of legs are then used to groom other parts of the body, and the only place they appear not to reach is the dorsal surface of the carapace.[12]^: 53

The body of M. inclemens is only sparsely covered with hairs and scales.

Jumping spiders have a distinctive rectangular carapace,[12]^: 51 and that of female Maevia inclemens average 2.30 millimetres (0.091 in) wide, while the carapaces of males average 2.10 millimetres (0.083 in).^[14]: 1989 The carapace of M. inclemens is fairly high, between 60% and 70% of the width.^[2]: 1

• 
  Female
• 
  Male, dark morph
• 
  Male, gray morph
• 
  Male, grey morph
• 
  Illustration of female
• 
  Illustration of males

Reproduction and lifecycle

Each morph accounts for 50% of the adult males, and they make the same number of attempts to court females, but using a different courting display.

After sighting a female, the tufted morph pushes himself as high as possible with the last three pair of legs, and claps with the foremost pair, while at the same time waving the palps up and down, and swinging its abdomen from side to side,[15]^: 95 usually about 9 centimetres (3.5 in) from the female.^{[13]: 161-162} In contrast, the gray morph crouches down and points the foremost two pairs of legs directly forward, crosses the tips of the legs creating a triangle-like configuration, holds his orange-colored palps beneath his forward eyes, and glides back and forth in stationary or receding semi-circles in front of the female, ^[15]: 95 at 3 centimetres (1.2 in) away.^{[13]: 161-162} The movements of the two morphs are identical later in the sequence.^{[15]: 95, 98}

When receptive, females respond similarly to both male types: approach and settle; extend the foremost pair of legs or tap with them.^[15]: 99 Both male morphs typically end their initial display and start leg-clapping and zig-zag dancing.^{[15]: 103, 106}

When tufted males clap, females look towards them and display a greater number of tap displays to them than to the gray morph. Females also respond to tufted morphs' clapping more often by settling than for gray males.^[15]: 102 However, after the females look towards the males, gray males approach the female more often than the tufted male.^[15]: 102 Females often tip their abdomens from side to side.^[15]: 102

Finally the male mounts and copulates with the female. Afterward, the male generally dismounts and the two pair usually run away from each other. However, the male sometimes chases the female and tries to copulate again.^{[15]: 103, 106}

In an experiment, 12 tufted (52%) and 14 gray males (54%) copulated with females after courtship. At the end of copulation, females tried to capture and eat the males, but in the same experiment only one tufted and one gray male were killed. A count of offspring showed no differences in numbers of spiderlings from the two morphs. However, gray males got females' attention more quickly within 8 centimetres (3.1 in) while tufted males were quicker between 8 and 30 centimetres (3.1 and 11.8 in) from the females. The continuation of two male morphs may be an example of a mixed evolutionarily stable strategy, in which both morphs are genetically determined by their fathers' morphs, and both are equally successful in their different ways.^[1]

• 
  Second instar spiderling
• 
  Immature male
• 
  Immature male

Distribution and habitat

Maevia inclemens is found throughout the eastern and mid-western

A study reported in 1981 on one mature and three recently clear-cut sites in the southern Appalachian Mountains near Highlands, North Carolina. All specimens of spiders that hunt were collected on plants or webs above ground. Clear-cutting caused a marked decrease in the abundance of nine species and a marked increase in four species, while M. inclemens and six others showed no change.^{[18]: 288, 291-292}

A few jumping spider species, including M. inclemens, have been able to establish themselves in man-made structures. Most often these spiders are found on outbuildings or structures such as fences, rather than in permanently inhabited houses.^[19]

Notes

a: ^ The full set of synonyms is: Attus inclemens, Attus ictericus, Attus protervus, Attus aspergatus, Attus vittatus, Attus niger, Maevia pencillata, Maevia annulipes, Plexippus undatus, Astia vittata, Attus petulans and Maevia vittata^[2]: 1-3

References

External links

Wikimedia Commons has media related to Maevia inclemens.

• Maevia inclemens at Salticidae.org
• Maevia inclemens species page at Bugguide.net
• Male Maevia inclemens at YouTube