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Courtship and male-male agonistic behaviour of Cosmophasis umbratica Simon, an ornate jumping spider (Araneae: Salticidae) from Singapore

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The courtship and male-male agonistic behaviour of Cosmophasis umbratica Simon, an iridescent jumping spider from Singapore, was studied for the first time. Exhibiting sexual colour and size dimorphism, C. umbratica is frequently found on leaves and flowers of tropical plants in open areas. Males are generally larger than females and dominantly green and black with silvery white markings; females are generally a mixture of green, brown, white and black. Sixteen major displays are described for C. umbratica. Skittering, vibrating of palps, arching of legs and flexed up abdomens are dominant male behaviours during courtship. Females almost always decamp on first sight of males, although males are very persistent in their courtship. A large repertoire of male-male agonistic displays is observed, with males either decamping after a clash, being lifted up and thrown down, or while embracing are chased away after being pushed back. Drumming is also displayed in both male-female and male-male interactions. This vibratory communication channel during inter- (male-female) and intra-sexual (male-male) interactions away from nests is discussed in regards to the evolution of salticids.
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THE RAFFLES BULLETIN OF ZOOLOGY 2004
THE RAFFLES BULLETIN OF ZOOLOGY 2004 52(2): 435-448
© National University of Singapore
COURTSHIP AND MALE-MALE AGONISTIC BEHAVIOUR OF COSMOPHASIS
UMBRATICA SIMON, AN ORNATE JUMPING SPIDER (ARANEAE: SALTICIDAE)
FROM SINGAPORE
Matthew L. M. Lim and Daiqin Li
Department of Biological Sciences, National University of Singapore, Singapore 119260.
Email: dbslidq@nus.edu.sg (DL)
ABSTRACT. – The courtship and male-male agonistic behaviour of Cosmophasis umbratica Simon, an
iridescent jumping spider from Singapore, was studied for the first time. Exhibiting sexual colour and size
dimorphism, C. umbratica is frequently found on leaves and flowers of tropical plants in open areas. Males
are generally larger than females and dominantly green and black with silvery white markings; females are
generally a mixture of green, brown, white and black. Sixteen major displays are described for C. umbratica.
Skittering, vibrating of palps, arching of legs and flexed up abdomens are dominant male behaviours during
courtship. Females almost always decamp on first sight of males, although males are very persistent in their
courtship. A large repertoire of male-male agonistic displays is observed, with males either decamping after
a clash, being lifted up and thrown down, or while embracing are chased away after being pushed back.
Drumming is also displayed in both male-female and male-male interactions. This vibratory communication
channel during inter- (male-female) and intra-sexual (male-male) interactions away from nests is discussed
in regards to the evolution of salticids.
KEY WORDS. – Spiders, Salticidae, Cosmophasis umbratica, sexual dimorphism, agonistic, courtship,
vibratory communication.
INTRODUCTION
Among spiders, jumping spiders (Salticidae) are the most
diverse family with approximately 5000 named species from
538 genera (Platnick, 2003). They are distinguished from all
other spiders by their unique, complex visual system and acute
vision (Land 1969a, 1985; Blest et al., 1990), including colour
vision (DeVoe, 1975; Forster, 1985; Nakamura & Yamashita,
2000) with an extensive spectral sensitivity (Peaslee &
Wilson, 1989). Though the visual ability has not precluded
communication involving other sensory modalities (Jackson,
1982), much of the inter- and intra-specific communication
of salticids is highly reliant on vision (Crane, 1949b; Forster,
1982a, b; Clark & Uetz, 1994; Jackson & Pollard, 1996, 1997;
Li et al., 1997). Selection pressures from the mate-choice
preferences of females have probably driven the evolution
of striking colour patterns and active visual courtship displays
in salticid males. The elaborate leg waving and stereotypic
dance displays may also facilitate species recognition
(Peckham & Peckham, 1889, 1890; Crane, 1949a; Forster,
1982a, 1985).
The anterior eyes (also called ‘principal eyes’) enable salticids
to recognize objects from 20-30 body lengths away (Jackson
& Blest, 1982; Harland et al., 1999), with secondary (lateral
and posterior) eyes being involved primarily in detection of
long range movement (Land, 1971). Together, the salticid’s
eight eyes support vision-mediated courtship, prey capture
and escaping from predators (Crane, 1949a, b, Land, 1969a,
b, 1985; Forster, 1982a, b). When encountering a potential
prey, most salticids adopt a typical stalk-and-leap sequence
(Forster, 1982a, b). If the object is a conspecific spider,
however, salticids behave differently. In typical male-male
agonistic encounters away from nests, salticids threaten each
other in leg-wave-and-grappling sequences (Wells, 1988;
Faber & Baylis, 1993; Taylor et al., 2001; Taylor & Jackson,
2003). In male-female encounters away from nests, salticids
use vision-dependent displays: a common pattern is for the
female to remain stationary while the male approaches in a
zig-zag courtship display, integrating various postures and
patterns of waving the forelegs (Crane, 1949b; Jackson, 1982).
Male-male agonistic and male-female courtship displays
during intraspecific interactions have been described in detail
for numerous species of salticids (e.g. Jackson 1986a, 1986b;
Jackson & Macnab, 1989; Richman & Jackson, 1992).
Intersexual displays tend to be especially elaborate and
complex (Peckham & Peckham, 1889, 1890; Crane, 1949a,
b; Forster, 1982a; Richman & Jackson, 1992; Jackson &
Pollard, 1997). Male-male interactions include more
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Lim & Li: Courtship and agonistic behaviour of Cosmophasis umbratica
behaviour that can be called aggressive (e.g. Crane, 1949a,
b; Richmond & Jackson, 1992; Faber & Baylis, 1993; Taylor
et al., 2001; Li et al., 2002). However, the number of salticid
species studied so far cover only a small fraction of the salticid
538 known genera.
Many species of salticids use distinctly different mating
tactics, involving both visual and non-visual communication
(e.g., Jackson, 1982; Jackson & Pollard, 1997). Appreciating
the varied sensory modalities used by salticids has led to
speculation about the evolution of salticids (Jackson & Blest,
1982). However, comparative data from a wide range of
species of saltcids combined additional comprehensive studies
of individual species are needed for evaluating evolutionary
hypotheses. Salticids are most diverse in the tropics. Tropical
salticids are of special interest also because they are often
especially ornate.
Despite being a small state, Singapore provides exceptional
opportunities for research on salticids. Being close to the sea
level and nearly on the equator in the wet tropics, Singapore
is a centre of extraordinarily rich biodiversity (Turner, 1994),
and this includes a very diverse spider fauna (Song et al.,
2002). There are 77 described salticid species in Singapore
(Song et al., 2002; Zhang et al., 2003), but there have been
studies of the displays of only four of these: Phaeacius
malayensis Wanless (Jackson & Hallas, 1986a), Epeus
flavobilineatus (Doleschall) (Jackson, 1988), Thorellia
ensifera (Thorell) (Jackson & Whitehouse, 1989), and Thiania
bhamoensis (Li et al., 2002). As a step toward our
understanding of Singapore salticids, we investigated the
courtship and male-male agonistic behaviour of Cosmophasis
umbratica, an especially active and colourful salticid.
MATERIALS AND METHODS
Individuals of Cosmophasis umbratica were collected in the
morning (0830-1100 h) from several parks in Singapore, but
especially from Kent Ridge Park and Clementi Park
Connector. Because observing the interactions of salticids in
the field is very difficult, we took adult spiders (12 males
and 19 females) from the field back to the laboratory for
detailed observations. Spiders were maintained individually
in cylindrical cages (diameter: 6.5 cm; height: 8.5 cm) in a
controlled-environment laboratory (relative humidity: 80-
85%; temperature: 25 ± 1ºC; light regime: 12 h: 12 h; lights
on at 0800 h). Additional lights (Arcadia Natural Sunlight
Lamp) were used to illuminate cages 4 h daily (0900-1100 h;
1600-1800 h) as these light tubes provided light spectrum
that simulated natural sunlight. In addition, these spiders were
most frequently spotted on plants exposed to sunlight during
late morning and early evenings (personal observations).
Water and sugar water were provided ad libium via dental
rolls. Spiders were maintained on a diet of houseflies (Musca
domestica), fruit flies (Drosophila melanogaster) and small
instars of crickets (Gryllidae sp.) twice a week. Testing
procedures, cage design and terminology were the same as
in earlier studies of salticids (Jackson & Hallas, 1986b). This
included convention that expressions such as ‘usually’ or
‘generally’, ‘sometimes’ or ‘occasionally’, and ‘rarely’ that
were used to indicate frequencies of occurrence of c. >80%,
20-80%, and <20%, respectively.
To observe male-male and male-female interactions, two
individuals of C. umbratica were used two at a time. A young
Simpor Air leaf (Dillenia suffructicosa) (length: 15-20 cm;
breath: 10-15 cm) was clamped to a stand that was held 20
cm above and parallel to test table. Both spiders (two males,
or a male and a female) were introduced onto the leaf at the
same time, but at opposing ends. An arrangement of 10 equi-
spaced Voltarc Ultra Light tubes (110W each), held 130 cm
above table was used to provide full-spectrum illumination
during the observations. A total of 12 adult males and 19
adult females were used. No individual was used more than
once on any given day for the same test, but might be used
on other days in the similar or different tests. The inter- and
intrasexual interactions were video recorded.
OBSERVATIONS
Habitat
Cosmophasis umbratica was often found on leaves and
flowers of ‘sun-loving’ flowering shrubs or plants that were
fully exposed to sunlight. One of these plants, Ixora javanica
(Fig. 1) (commonly known as ‘Ixora’ or ‘Javanese Ixora’) is
native to Southeast Asia and commonly planted in parks for
aesthetic purposes as it flowers all year round (Fig. 2). Like
many salticids (Jackson et al., 2001), C. umbratica is
nectivorous and we often found it on or near the inflorescences
of Javanese Ixora (Fig. 3).
Morphology
Cosmophasis umbratica is a small jumping spider (body
length: adult male 5 – 7 mm; adult female c. 5 mm) showing
sexually dimorphism in colour and size. The males have
complex iridescent markings on several body regions, but
especially on the dorsal and sides of cephalothorax, and on
the sides of the femora of all of the legs. The abdomen is
mostly black with silvery white lines (Fig. 4). The female is
generally green (dorsal and side cephalothorax) with a mixture
of brown, white and black coloration on the abdomen (Fig.
5). Morphologically, males have slimmer abdomen and longer
legs than females. Sexually mature males are readily
identifiable from sub-adult males by the presence of a black
tip on the tarsi of the palps, and the presence of white hairs
on the face (Fig. 6).
Nest structure
Males and females of Cosmophasis umbratica built similar
nests: a silken sheet and a tube with entrances on both ends.
The sheet was wide at the ends, and narrowed as it approached
the doors of the tube. The sheet covered over the silken tube
(Fig. 7). Prior to oviposition, the gravid female sealed the
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THE RAFFLES BULLETIN OF ZOOLOGY 2004
doors and remained inside the nest. The nests of C. umbratica
were commonly found in-between leaves of Ixora, or at times
on the base of the inflorescences.
Normal locomotion
The normal locomotion of C. umbratica was characterized
by rapid stop-and-go gaits (stepped forward for 0.3-0.8 s;
paused for 0.3-0.6 s). Stepping forward mirrored either a
straight line or an arc. A single bob started when the spider
paused during stepping and raised its abdomen to a maximum
height, and ended when the abdomen was lowered. Ascent
and descent of the abdomen was normally smooth and seldom
jerky. The abdomen was usually parallel to substrate when
the spider transverse between pauses, though posterior of the
abdomen was sometimes nearer to the ground than the anterior
of the abdomen during a pause after bobbing.
Bobbing of abdomen during normal locomotion involved the
quick and jerky flexing up and down (30-70
o
) of abdomen
within the sagittal plane. Two types of abdominal bobbing
were observed: low (duration 0.3-0.4 s, abdominal flexed
at.30-50
o
) and high (0.4-0.6 s, abdominal flexed at c.50-70
o
)
bobbing, the latter being more common. Stepping faster
usually meant faster bobbing, though the spider never steps
while raising its abdomen. However, the spider usually had
already started to step when the abdomen had lowered to about
30˚ during abdominal descent. In the event of low abdominal
bobbing, the spider had already begun to step after onset of
abdominal descent. Though single bobbing was common
during normal locomotion, double and triple bobbing were
also observed but rare. Double and triple bobbing are events
where a single bobbing is repeated once and twice,
respectively, without the spider stepping off. Most double-
bobbing events lasted only 1 s, and double-bobbings ending
with low abdominal bobbing resulted in similar stepping
pattern as a low abdominal bob: the subject stepped off after
onset of abdominal descent
Although the angles of femur-patella and tibia-metatarsus
joints were variable, generally all legs were slightly flexed,
with legs I and II generally pointing forward, legs III to the
side, and legs IV pointing backwards. Legs were well spaced
out, with legs I and II normally held at about 70-90º and 150-
170º apart respectively, and with femur of both legs facing
the front (angled about 30-45º to the axis). Legs III generally
pointing sideways (150-170º apart) with tarsi directed
forward, and legs IV were held close to the abdomen at about
30-45º apart, with tarsi pointed backwards and diverged. Legs
were never observed to be close to each other in any instances
during normal locomotion.
Palps were held in front of the face, and hid either part or
most of the chelicerae from view (Fig. 8). The angle of the
palpal femur-patella joint varied from 30˚ to 90˚, with the
femur held near to face with tarsi pointing down or pointing
forward (tarsi at c. 70˚ to femora), or a ‘raised palp’. Palps
were never observed to be fully extended or erect during
normal locomotion. While at rest, palps were usually
positioned or waved (about 5/s) at close proximity of each
other, but palps rarely touched the substrate. Waving of both
palps were often in matching phase with each other, and often
occurred with bobbing of abdomen, but the matching phase
of abdomen bobbing and palps waving was not evident.
Figs. 1-3. (1) Javanese Ixora, Ixora javanica, a common garden
flowering plant on which Cosmophasis umbratica and many salticids
were frequently found; (2) Ixora commonly planted along roads and
paths in parks; (3) C. umbratica on a red inflorescences of Ixora.
1
2
3
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Lim & Li: Courtship and agonistic behaviour of Cosmophasis umbratica
Elements of behaviour occurring during intraspecific
interactions
Some behaviour elements were based on movement patterns.
Others were static, with the spider holding body parts in
particular stances for sustained periods. A total of 29 elements
of behaviour are described. These are listed below with each
element of behaviour being given an index number: arched
legs (6), bent abdomen (5), block (19), clash (29), copulation
(22), creep (3), decamp (18), drumming palps (14), elevated
legs (9), embrace (24), extended legs (7), extended palps (12),
flexed up abdomen (4), grapple and push (25), hook and push
down legs (23), hunched legs (8), lift up and throw (26),
lowered body (2), lunge (28), mounting and postmount
behaviour (21), opened chelicerae (11), posturing (10), prod
(20), raised body (1), rapid extend and retract legs (27),
scraping palps (15), short skitter (17), skitter (16), vibrate
palps (13). The contexts in which behaviours considered to
be displays occurred are indicated in Table 1.
1. Raised body. – When raised, bodies were held higher than
normal above the substrate (Fig. 9). The abdomen was
normally elevated, but the anterior cephalothorax was usually
held higher than the posterior.
2. Lowered body. – When lowered, the bodies were positioned
close to substrate, with the abdomens almost parallel to the
substrate (Fig. 10).
3. Creep. – When crept, bodies were lowered with legs I fully
extended and often parallel to the substrate and to each other,
with tibia dipping down a little. Palps were also extended
(see Element 11, Position 2) (Fig. 11) and usually parallel to
substrate.
4. Flexed up abdomen. – When flexed up, the abdomen was
normally held c. 70˚ from the cephalothorax, with the anterior
cephalothorax often held lower than the posterior (Fig. 12).
Figs. 4-6. (4) Male C. umbratica (front dorsal view), with blue-green (dorsal) and violet iridescence on the sides of femurs of legs I to IV,
a line of iridescence on the dorsal abdomen from anterior to posterior, and a white line along each side of abdomen, which were joined at
the anterior abdomen but discontinued at the posterior; (5) Female C. umbratica (front dorsal view). Females are generally less iridescent
and have a shorter yet plump abdomen as compared to the slim and elongated abdomen of males; (6) The face of a juvenile C. umbratica
(6a) lacks white hairs indicating a sexually matured male C. umbratica (6b), and black coloration on the tarsus of a palp (6c), a coloration
prominent on an adult male’s palps (see Fig. 4).
45
6c6b6a
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THE RAFFLES BULLETIN OF ZOOLOGY 2004
5. Bent abdomen. When bent, the abdomen was tilted about
30˚ to the right or left of the sagittal plane of the cephalothorax
(Fig. 13). Sometimes the abdomen was also flexed up c. 30˚
when bent (Fig. 14).
6. Arched legs. - When legs I and II were arched, the side of
the femur that faced the front angled at c. 45˚ to the vertical
plane (perpendicular to sagittal plane). The femur of both
legs were almost parallel to substrate, and both left and right
pairs of legs I and II were at about 120˚ apart, resulting in an
almost parallel or close positioning of legs I and II from both
sides. With femur-patella and tibia-metatarsus joints slightly
flexed on both legs I and II, the tarsi contacted the substrate
(see Fig. 12).
7. Extended legs. – When extended, the femur-patella joints
of legs I were slightly flexed and the joints distal to femur-
patella were fully stretched and held almost parallel to
substratum, with the tarsus angling down slightly at times
(Fig. 11).
8. Hunched legs. – When hunched, legs I and II were highly
flexed at femur-patella and tibia-metatarsus joints, so that tarsi
pointed down (leg I) and slightly inwards (leg II) (Fig. 15).
Both legs I and II were held almost perpendicular to the
sagittal plane of the body. The abdomen was usually bent,
and sometimes also slightly raised (c. 30°) from the
cephalothorax.
9. Elevated legs. – Legs I were elevated, and two modal
positions were discerned. In Position 1, the femur was held
almost perpendicular to the substrate and close to the
cephalothorax, with femur-patella slightly flexed and joints
distal to femur-patella fully stretched, such that metatarsi and
tarsi were held about 60˚ from substrate and about 30˚ from
each other (Figs. 16a and 17). Position 2 differed from
Position 1 because all joints were fully extended, and the stiff-
looking legs I were almost perpendicular to substrate (pointing
upwards vertically) and almost parallel to each other (see Figs.
16b, d).
10. Posturing. – The spider postured by standing or stepping
as it held its stationary legs arched (arched posturing), bent
(bent posturing), elevated (elevated posturing), extended
(extended posturing), or hunched (hunched posturing).
11. Opened chelicerae. – When chelicerae were held opened,
the basal segments were held 30° - 90° apart. Fang extension
was variable. When maximally extended, fangs pointed
straight down as the maximum. In Position 1, basal segments
Table 1. Major elements of intraspecific behaviour (list alphabetically) of Cosmophasis umbratica and the types of interactions during which
they usually occur. Male-female: behaviour performed by males during male-female interactions. Female-male: behaviour performed by
females during male-female interactions. All interactions occur away from nests. + = occurred; × = did not occur.
Male-female Female-male Male-male
Arched posturing + ××
Bent posturing × ++
Elevated posturing
Position 1 ×××
Position 2 ×××
Extended posturing + ××
Hunched posturing × ++
Rapid extended and retracted posturing ××+
Clash ××+
Creep + ××
Embrace ××+
Grapple and push ××+
Lift up and throw ××+
Lunge ××+
Short Skitter ××+
Skitter + ××
Drum palps + ××
Scrape palps + × +
Vibrate palps + × +
Fig. 7. A silken nest, consisting of a not so dense silken sheet
covering a silken tube spun by male C. umbratica in a petri dish.
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Lim & Li: Courtship and agonistic behaviour of Cosmophasis umbratica
Figs. 8-14. (8) Male C. umbratica (facing right). Position its palps in front of its chelicerae during normal locomotion; (Insert) front view
of C. umbratica using palps to cover its chelicerae; (9) Male C. umbratica (facing right). Raising the body with abdomen parallel to substratum;
(10) Male C. umbratica facing right with body lowered; (11) Male C. umbratica (facing left) creeping towards a female facing right (partially
hidden) with extended palps and extended legs that are almost parallel to substrate; (12) Male C. umbratica (front view) posturing with
flexed up abdomen and extended palps (Position 2); (13) Male C. umbratica hunching and bending its abdomen to its left; (14) A side view
of the agonistic display of male C. umbratica (facing left) hunching, raising and bending his abdomen to his right.
8
9
10 11
12 13
14
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THE RAFFLES BULLETIN OF ZOOLOGY 2004
Figs. 15-16. (15a) Male C. umbratica (facing right) posturing with hunched legs and bent abdomen; (15b) Male C. umbratica (facing on-
view) with hunched legs and abdomen not bent; (16a-f) Sequence of main events during agonistic interactions between two males: (16a) two
males with elevated legs (Position 1); (16b) two males embracing each other (no pushing was observed) with legs I elevated (Position 2),
chelicerae opened with fangs pointed downwards (Position 2), palps extended (Position 3), and body raised; (16c) the larger male (right)
hooking and pushing the smaller male, with legs IV flexed at femur-patella-tibia such that body is raised, with posterior (abdomen) higher
that the anterior (cephalothorax); (16d) the larger male chasing away the decamping male with elevated legs I (Position 2) and extended palps
(Position 3); male (in background) in process of decamping; (16e) the larger male lifting up the smaller male after both were engaged in a
hook and grapple; (16f-g) after a clash, males tend to quickly extend and retract legs (male in background).
15a 15b
16a
16b
16c
16d 16e
16f 16g
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Lim & Li: Courtship and agonistic behaviour of Cosmophasis umbratica
Figs. 17-24. (17) Male C. umbratica posturing with elevated legs (Position 1) during agonistic interactions with another male (partially
hidden); (18) Male C. umbratica in a hunched position with chelicerae opened and fangs showing a little (Position 1); (19a-d) Sequences
before an embrace of two male C. umbratica, with chelicerae opened in Position 3: (19d) extension of palps (Position 3) were only prominent
just before contact; (20) Male C. umbratica (facing right) posturing with flexed up abdomen and extended palps (Position 1); (21) Male C.
umbratica with almost fully extended palps contacting the substrate; (22) A slightly flexed palps on contact with the surface during agonistic
displays. Here the male has a slightly raised and bent abdomen; (23) Copulating position of C. umbratica, with the male’s leg II (facing right)
going over the female’s cephalothorax (facing downwards); (24) Male C. umbratica (facing on-view) copulating with a female (facing
inside). The female’s abdomen was rotated about 30˚ and lifted slightly from its lowered body posture, so that access to the epigynum and
engagement of palp will be faster and easier. During copulation the male always faces the opposition direction of the female, though this
position may change as copulation proceeds, with the female failing in her attempt to pull away, or with males pushing slightly at the female.
17
18
20
21
22
23 24
19a 19b
19c 19d
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THE RAFFLES BULLETIN OF ZOOLOGY 2004
were held about 30-60° apart, with fangs showing but not
pointing downwards (Fig. 18). In Position 2, the basal
segments were held about 30-60° apart, with fangs pointing
down (see Figs. 19, 16b).
12. Extended palps. - When extended, the joints distal to
femur-patella on palps were fully stretched, and three
positions occurred. In Position 1, extended palps were held
at c. 45˚ down from the horizontal plane of the cephalothorax
(Fig. 20). When fully extended, palps were about parallel to
the dorsal part of the flexed up abdomen. Sometimes both
palps were parallel to each other. More often their tarsi
converged somewhat, but without contact at both ends of the
tarsi. In Position 2, fully extended palps were held parallel to
substrate (see Fig. 12). Otherwise, Position 2 was similar to
Position 1. In Position 3, the palps extended upwards, almost
perpendicular to the substrate, and about 30˚ from each other
(see Fig. 16b).
13. Vibrate palps. – When palps vibrated, they moved up
and down together in matching phase. While they vibrated,
they remained extended or they were slightly flexed (femur-
tibia angled about 150˚). When vibrating palps, the highest
position was when the femur was raised such that tibia were
almost parallel to substrate (Element 12 Position 2). The
lowest position was when femur was lowered such that tibia
was c. 45˚ to the horizontal plane (Element 12 Position 1).
Rate varied from 0.05 s to 0.2 s per cycle, and bout duration
was usually about 1s.
14. Drumming with palps. – When palps drummed on the
substrate, tarsi made contact (Figs. 21, 22). Palps were held
slightly flexed (femur-patella-tibia angle about 120˚).
Movement was at low amplitude (c. 10˚), and much variation
in rate, duration and phasing was observed.
15. Scraping with palps. – When scraping, palps were held
slightly flexed (femur-tibia angled about 120˚). The palp tarsi
moved c. 1 mm across the substrate, maintaining contact with
substrate, for 1 s. Phase matching between palps during
scraping was not evident.
16. Skitter. – Skittering was somewhat similar to the stop-
and-go gaits seen in normal locomotion, except that stepping
was of shorter duration and route taken different. The spider
spent less time moving (0.3-0.5 s) during zigzag (spider
stepepd left or right for 0.3-0.5 s, halted for <0.3 s, then
stepped in opposite direction for 0.3-0.5 s, halted for <0.3 s,
and cycle repeated) and stop-and-go (spider stepped forward
for 0.3-0.5 s, halted for <0.3 s, then stepped forward for 0.3-
0.5 s, and cycle repeated) skittering as compared to normal
locomotion. Arc skittering was less common compared to
zigzag and stop-and-go skittering, and time taken to complete
arc skittering was dependent on distance, which occurred in
bouts lasting 0.4-1.4 s and covering distances ranging from
1 to 4 body lengths. During skittering, the male’s abdomen
often remained flexed up (c. 70˚). Spiders seldom bobbed
their abdomens while skittering.
17. Short skittering. – Short skittering differs from skittering
generally in the spider’s posture during stepping and halting.
When short skittering, the spider tended to remain stationary
for about 0.4 s while legs were in a hunched position, and
moved for about 0.2 – 0.4 s, at times maintaining their
hunched posture even while moving. Routes taken mirror
those of zigzag and stop-and-go skittering, except that
distance covered between halts was shorter (<1 body length).
Vibrating of palps during halts in short skittering was similar
to that of males when posturing in front of females, with the
exception of palps being more flexed (femur- tibia angle about
120˚) and never fully extended.
18. Decamp. – One spider decamped by either running or
jumping away from the other spider (see Fig. 16d).
19. Block. – In an apparent attempt to prevent the female
from running past, the male spider moved sideways so as to
stay in front of the female. Blocking usually resembled a zig-
zag skittering of short duration where the male skittered over
the apparent decamping route of the female. However
duration of blocking attempts by the male depended on
locomotion and direction of the female’s decamping.
20. Prod. When the male decamped, the female chased after
him, sometimes with her face intermittently coming into
contact with the male’s posterior abdomen.
21. Mounting and Postmount behaviour. – Upon contact
and after creeping, the male used his extended legs I to tap
the female’s legs I. Next he proceeded to use legs I and II to
tap the female’s legs I and II. All this normally happened
within c. 1s, with the female tapping back, before walking
over the female. As the male walked over the female’s
cephalothorax, the female lowered her body. When the
cephalothorax of the male was over the female’s
cephalothorax, the male then positioned himself either slightly
to the left or slightly to the right of the female’s body. He
stroked with legs I on the female’s abdomen on the same
side as copulation (if male used right palp, then the right leg
I stroked the right ventral side of the female’s abdomen). Legs
II were positioned over the female’s abdomen, but did not
stroke (Fig. 23). Slight movement of both of the male’s palps
could be seen during and after mounting, but details were
not discerned. The female’s abdomen was slightly raised and
rotated 30˚- 60˚ to either the left or the right. Copulation (Fig.
24) started within 10 s after the male’s first contact with the
female.
22. Copulation. – Copulation ended when either spider
decamped. In seven male-female interactions, a total of six
separate copulations took place in 2 mating pairs. The males
copulated with engaging of either one palp, or the engaging
of one palp followed immediately by engaging of the other
palp without the female decamping. Four separate copulations
were recorded for one mating pair (the copulation durations
were: (1) 25 s, one engagement (3 separate copulations); (2)
21.5 min, two engagements, 90 s, right palp, followed by 20
min left palp (1 separate copulation). Two separate
copulations were observed for the other mating pair (the
copulation durations were: (1) 10 min, one engagement; (2)
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Lim & Li: Courtship and agonistic behaviour of Cosmophasis umbratica
35 min, one engagement). The male and female faced opposite
directions during copulation, with the right palp engaged
under the right side of the female.
23. Hook and push down legs. – One spider used its legs I
to hook and push down a leg of the other spider (the
‘opponent’) following an embrace (see Element 24). The legs
used for hooking were held with the femur angled up and
with both patella-tibia and tibia-metatarsus joint slightly
flexed (tarsi pointed to the side). Contact with the other
spider’s legs was maximal along the tibia and metatarsus
during attempts to hook each other. Initially each male
appeared to try to raise its own legs I over the other’s, and
the male that succeeded in hooking its opponent (see Fig.
16c) will then push its opponent’s legs 1 down.
24. Embrace. – When spiders embraced, both spiders’ legs
I were elevated in Position 2 with chelicerae and palps coming
into contact (see Fig. 16b). Chelicerae were opened (Position
2) and palps were extended (Position 3). The spiders’ bodies
were raised, with the anterior part of the abdomen higher than
the posterior. The duration of an embrace is about 0.5 – 1.0
s.
25. Grapple and push. – When spiders grappled and pushed
(one spider forcing another spider backwards) each other, the
spiders’ legs I were in hooked position, chelicerae were
opened (Position 2) and palps extended (Position 3), and faces
tightly pressed together (see Fig. 16c). Bodies were usually
raised. Femur-patella joints of legs III and legs IV were
slightly flexed (more pronounced in legs IV), such that the
posterior end of the spider was higher than the anterior. Legs
II were almost fully extended, perpendicular to the sagittal
plane of the body and touching the ground.
26. Lift up and throw. – With body positioned as when
grappling and pushing, one spider (usually the larger male)
raised its body and lifted up the other spider. The spider that
did the lifting had the anterior part of the cephalothorax much
higher than the posterior end (Fig. 16e). When one spider
was lifted to the maximum height reached (all legs lost contact
with substrate), the other spider suddenly released its legs I
hook posture (see Element 23), such that it landed awkwardly
upon contact with substrate, at times upending itself.
27. Rapid extend & retract legs. – When extending and
retracting, the femur-patella and tibia-metatarsus joints of legs
I and II were flexed at 50-70˚, with the whole process lasting
< 1 s, and one complete cycle (one extension and retraction
of one side of legs I and II) at c. 0.08s. During extension
phase, the femur-patella joints were slightly relaxed, such that
legs I and II reached forward and away from body as both
tarsi made contact and pointed downwards. During the
retracting phase, both legs I and II had the femur-patella joints
flexed and patella raised closer to body, such that both tarsi
(not necessarily touching) were still pointing downwards but
held further from substrate. Both pairs of left and right legs
extend and retract in opposite direction (with femur held close
to the face, segments distal to femur were held extended) such
that tarsi pointed forward and diverged. Femur-patella joints
of palps flexed at 85-90˚, such that palps made contact with
legs I at the tarsi during extending and retracting (see Figs.
16f-g).
28. Lunge. – One or both spiders suddenly lunged forward
or towards the other spider by raising the posterior end of its
body and extending its rear legs, such that the posterior end
of the spider is higher than the anterior end of the
cephalothorax, with legs 1 elevated (Position 2). Distance
between both spiders is about 1 to 1.5 body lengths (see Fig.
16a).
29. Clash. – When one or both spiders lunged towards the
other or towards each other with elevated legs (Position 2),
both spiders came into contact with leg I tarsi touching,
resulting in either one or both spiders being pushed back.
Organization of behaviour
Inter- and intrasexual interactions (staged on leaves) began
when one spider started to display
(definition of display in male-female interactions: flexed-up
abdomen, vibrating of palps and arched legs; definition of
display in male-male interactions: hunched legs) to the other
spider. After the initial display, observation of an interaction
continued until one spider decamped, with the other spider
failing to watch and follow, both spiders decamped and either
one or both jumped off, or an interaction failed to occur within
30 min, after starting a test (i.e. both spiders placed together
on the leaf). There was an interaction in 16 observations
(male-male, 9 of 12; male-female, 7 of 12). Male-male
interactions were much shorter than male-female interactions,
with male-male agonistic interactions lasting from 0.15-0.5
min and male-female interactions lasting 0.15-10 min (time
in copula excluded). In male-female interactions, females
frequently decamped as soon as the male came into view,
but the decamped female usually returned several seconds
later. Decamping and returning by females and persistent
courtship by males was repeated numerous times in both
successful and unsuccessful male-female interactions.
Cannibalism was never observed.
The male-female interactions
Skittering was the dominant element of the male’s behaviour
during male-female interactions. Females usually decamped
immediately upon coming into view. There were variations
in distance during male and female interactions, from four
body lengths to ten body lengths. When the male initially
faced the female, the male’s behaviour became noticeably
more ‘excited’. He faced the female directly with body raised,
abdomen flexed up, legs arched and palps vibrating. If the
female did not decamp and instead faced the male, the male
then proceeded to skitter with flexed up abdomen and
vibrating its palps. Many skittering events, however, resulted
in females decamping as males approached. Males however
continued to skitter towards the on-looking female if it did
not decamp or turn away. Sometimes the male drummed and
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THE RAFFLES BULLETIN OF ZOOLOGY 2004
scraped palps while he postured with flexed up abdomen and
arched legs after the female had decamped or had turned away
from him. After the female decamped, the male drummed or
scraped the substrate only if the female was still in close
proximity (about 5 body lengths or less away) and within
sight of the male.
On some occasions the female bent her abdomen or prodded
the male. In a few cases, when the female did not decamp
after the male had appeared, she bent her abdomen, and the
male either decamped immediately or only after persistent
prodding by the female. Occasionally decamped females
attempted to run past the male while the males were posturing
or in the process of skittering. In these instances, the male
normally attempted to block the female by skittering sideways
to block her path. Males were never observed to bend their
abdomens in any interactions with females, and on few
occasions did it follow any females that had decamped or
after an unsuccessful blocking.
If the female did not decamp, the male postured, skittered
and crept towards her with legs I extended, and then mounted.
Females always lowered their body prior to mounting and
during copulation females might attempt to pull away, though
this was seldom observed. Copulation effectively ended with
females’ successful attempt to pull away from the male.
Duration of copulation was highly variable, but was
noticeably longer in copulations involving simultaneous
engagements of left and then right palps (see Element 22
Copulation on data on simultaneous palp engagements).
The male-male interactions
Male-male agonistic interactions began when one or both
spiders started to display (raised bodies, hunched legs, and
bent abdomens that were sometimes raised) at about 10-15
cm away. Both males then slowly short skittered towards each
other with opened chelicerae (Position 1), vibrating their palps
during pauses until they were about 2-3 body lengths apart.
One or both spiders then lunged forward with legs elevated
(Position 1), chelicerae opened (Position 2) and palps
extended (Position 3). After a clash (see Element 29), majority
of spiders that were pushed back eventually decamped, and
the other spider chased after the decamping spider. If no
spiders decamped, what proceeded next depended on size
differences between the two males.
On two occasions when a smaller male did not decamp after
a clash, both males then approached each other with elevated
legs (Position 1), opened chelicerae (Position 2) and extended
palps (Position 3). Both males attempted to hook and push
down each other’s legs, grappled and pushed each other, and
eventually the larger male lifted up the smaller male, held it
up for about 2 s, and then threw the smaller male, after which
the smaller male decamped while the larger male chased it.
The duration of conspecific male interactions was generally
shorter between males of different sizes than those of similar
sizes.
When the two males were similar in size, the clash often ended
with neither decamping. In these instances, both males then
proceeded to extend and retract their legs rapidly. The two
males always both performed rapid extending and retracting
of legs, but not necessarily simultaneously. While one male
was rapidly extending and retracting his legs, the other male
sometimes scraped both palps on the substrate. Both spiders
often would then raise their bodies as a preliminary to
embracing, and then proceeded to elevate their legs (Position
2) so as to hook and push down each other’s legs. Both spiders
then grappled and pushed, with chelicerae opened (Position
2) and palps extended (Position 3). The duration of hooking
and pushing legs down, grappling and pushing was about 2
s. Eventually one male succeeded in pushing back the other
male, often proceeded by a chase after a decamp.
DISCUSSION
The size and complexity of the display repertoire of
Cosmophasis umbratica from Singapore resemble that known
for other salticids’ intra-specific (i.e. male-male and male-
female) interactions that have been studied in detail (e.g.
Jackson, 1980, 1986a, 1986b; Jackson & Macnab, 1989;
Jackson & Whitehouse, 1989; Li et al., 2002). In the male-
male and male-female interactions of C. umbratica, a total
of 18 ‘major displays’ (see Moynihan, 1970) were performed
away from nests: posturing with legs (1) arched, (2-3) elevated
at Position 1 and 2, (4) extended, (5) hunched, (6) rapid
extended and retracted, (7) clash head on, (8) creep, (9)
embrace, (10) grapple and push, (11) lift up and throw, (12)
lunge forward, (13) abdomen bent, (14) skitter towards a
female, (15) short skittered towards a male, (16) drum palps,
(17) scrape palps, and (18) vibrate palps. This is much more
than the number of major displays away from nests estimated
for Epeus from Singapore (8) (Jackson, 1988a), Cobanus
mandibularis from New Zealand (9) (Jackson, 1989),
Cyllobelus rufopictus from Kenya (12) (Jackson, 1986a), and
Cosmophasis micarioides from Australia (13) (Jackson,
1986b). It is comparable to the number of major display away
from nests estimated for Thorellia ensifera from Singapore
(19) (Jackson & Whitehouse, 1989), Jacksonoides
queenslandica (20) (Jackson, 1988b) and Tauala lepidus (21)
(Jackson 1988c) from Australia, and Corythalia canosa (22)
from America (Jackson & Macnab, 1989), but considerably
fewer than those for Bavia aericeps from Australia (32)
(Jackson, 1986c), Holoplatys from New Zealand (27)
(Jackson & Harding, 1982), and Phidippus johnsoni (24) from
America (Jackson, 1977).
The courtship and agonistic (male-male) displays of C.
umbratica (Singapore) and C. micarioides (Queensland,
Australia) (see Jackson, 1986b) away from nests are quite
similar, though some differences exist. Skittering, as well as
vibrating of palps and arched posture are the dominant
courtship behaviours in both Cosmophasis species. When a
female tried to decamp, both C. micariodes and C. umbratica
males attempted to block her departure. If unsuccessful, only
C. umbratica males continued scrapping and drumming the
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Lim & Li: Courtship and agonistic behaviour of Cosmophasis umbratica
palps on the substrate, maintaining its courtship posture (of
arched legs and flexed up abdomen). This courtship
persistence of C. umbratica males, together with the
drumming and scrapping of palps, suggests that vibratory
courtship may be involved not only when males court females
away from nest, but also when at nest.
Courtship versatility is common among salticid species (e.g.
Jackson, 1980, 1986a; Jackson & Whitehouse, 1989; see also
Jackson, 1986d), with vibratory courtship usually prevalent
when a male courts a female at nest, and visual courtship
while away from nest. Jackson (1986b) suggested that the
act of skittering in C. micarioides, regardless of location,
could have a dual function: as a visual courtship (primarily
away from nest), and as a vibratory courtship (away and at
nest). As plants are ideal substrate for transmitting vibratory
signals (see Miklas et al, 2001; see also Rovner & Barth,
1981), vibrations from unique movements of males during
courtship away from nests could indeed be transmitted
through the leaves to the courted female, thus functioning as
both visual (if females are within sight) and vibratory
courtship. Examples of movements with such possibilities
are zigzag dancing in salticids such as Epeus (see Jackson,
1988a), T. lepidus (see Jackson 1988c), T. ensifera (see
Jackson & Whitehouse, 1989) and in primitive salticids Cyrba
algerina (see Jackson & Hallas, 1986a) and Cyrba ocellata
(see Jackson, 1990); juddering in C. rufopictus (see Jackson,
1986e), the successive approaches and withdrawals and
jerking in the primitive salticid Asemonea tenuipes (see
Jackson & Macnab, 1991) and on-erect tapping in C. canosa
(see Jackson & Macnab, 1989). Another primitive jumping
spider genus, Portia (Jackson & Hallas, 1986b) is known to
use both vibratory and visual displays when interacting with
conspecifics on webs, and use only visual displays when away
from webs. Large tropical wandering spiders, Cupiennius
salei (Araneae: Ctenidae) also engage in pre-copulatory
communication by sending mainly vibrations through vertical
movements of abdomens and scratching and drumming of
palps on a leaf (Barth, 1993; Rovner & Barth, 1981). In wolf
spiders, Hygrolycosa rubrofasciata females are known to
respond faster to males with higher drumming rate and
volume (Parri et al, 1997). In C. umbratica, the dominant
male display elements of skittering, vibrating of palps and
legs arching could probably serve as both vibratory and visual
signals, since C. umbratica is observed to be a leaf-dweller
and is also found on leafs of plants exposed to sunlight in the
morning and evening. Though drumming and scraping on
leaves in C. umbratica may indicate the possible web-building
ancestry of the Salticidae, further observations are needed to
investigate whether vibratory communications are involved
in both C. umbratica inter- and intrasexual interactions (on
the nests and near the vicinity of a female’s nest).
The agonistic male interaction of C. umbratica is observed
to generally follow a sequence but also exhibit variation in
confrontations when dealing with competitors of different
sizes. Conspecific male encounters generally occur in a
temporal sequence (visual to tactile), progression of proximity
(far to near), increasing energy expenditure and risk of injury
(low to high). Variation in male agonistic behaviour may
provide an avenue for both males to visually assess each
other’s physical strength, so as to avoid risk when conspecific
competitors are of different sizes. In Bavia aericeps (see
Jackson, 1986c), males postured to each other when within
sight, and engagements escalated to physical contact,
sometimes with one spider (always the smaller spider) being
upended. In C. umbratica, smaller males are always the ones
that are lifted up and thrown. Further examination, however,
is needed to investigate variations in body size as possible
factors that may influence male-male contest outcomes. In
general, the threat displays of C. umbratica are similar to
other salticids during conspecific male agonistic interactions:
increase in apparent body size (elevated and hunched legs),
weapons display (opened chelicerae), show of strength (hook,
embrace, grapple and push, lift up and throw and clash) and
movements intended for aggressiveness (lunge).
It is interesting that C. umbratica exhibits strong sexual colour
dimorphism, where the iridescence coloration only prevails
in adult males, and not in juveniles or females. The ornate
colorations of C. micarioides (Jackson 1986b), Thiania
(Jackson 1986f) and Brettus cingulatus (Jackson & Hallas,
1986a) were suggested to aid in concealment rather than
intersexual selection in the spiders’ natural surroundings.
However, the possibility of a eucryptic nature in the colours
of C. umbratica rather than colours derived from intersexual
selection is unlikely, as both adult males and females have
similar foraging niches (i.e. time of day and light
microhabitat), and if the iridescent coloration was eucryptic,
females may be at a greater disadvantage of being less cryptic
than males. Moreover, the usually inactive and sudden rapid
movements of Thiania and B. cingulatus during normal
locomotion, coupled with their iridescence natures, is
suggested to resemble iridescent reflections from sunlight
penetrating the canopy and striking drops of water, providing
effective camouflage in their natural environments. In
contrast, both C. micarioides and C. umbratica are also highly
active ornate spiders, prefer open habitats exposed to direct
sunlight, with normal locomotion mainly characterized by
rapid stop-and-go gaits and bobbing of abdomen. Therefore,
the acquisition of bright coloration and high iridescence in
sexually matured males, with both sexes’ preference for
niches exposed to open sunlight, coupled with high visual
acuity and colour vision, suggests that C. umbratica (and
possibly C. micariodes) may be a result of intersexual
selection, and is therefore an ideal model for study of female
mate choice and male-male competition studies, although the
possibility of the coloration due to both intersexual selection
and an eucryptic nature cannot be ruled out.
ACKNOWLEDGEMENTS
This work was supported by grants (R-154-000-1072-112 and
R-154-000-140-112) to D. Li from the National University
of Singapore Academic Research Fund. We are grateful to
Wee Khee Seah for her comments on manuscript, Lian Pin
Koh for helping us in the collection of the spiders, and also
to Poh Moi Goh for keeping the spiders alive with her ready
supply of houseflies. We also thank Singapore National Parks
Board for the permit (NP/RP104).
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... The visual modality has been extensively investigated in this species Li 2006a,2006b;Lim et al. 2008;Li 2013, Painting et al. 2016), and UV coloration is known to be condition-dependent Painting et al. 2017). However, vibratory signals have yet to be documented in this species, though their role during courtship interactions has been assumed (Lim and Li 2004). Thus, the first aim of this study was to establish and quantify vibratory signals in male C. umbratica as well as to examine whether vibratory signals carry information about male mass. ...
... Cosmophasis umbratica individuals (N = 128) were collected between August 2015 and February 2016 in Singapore. They were collected mainly between 0830 and 1200 h, as it is the time when they are active and most visible on the leaves of Javanese Ixora (Ixora javanica), the shrub on which they are predominantly found (Lim and Li 2004). Large juveniles and subadults were retained for rearing in the laboratory, so they were known to be virgins. ...
... Male C. umbratica multimodal courtship displays comprised visual posturing and motion displays (Lim and Li 2004), ornate iridescent body coloration (Lim and Li 2006b), and substrate-borne vibrations. Two main vibratory signals were observed in all courtship displays. ...
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Ultraviolet (UV; wavelengths: 280–400 nm) coloration has been shown to be an important visual signal but has not been studied in conjunction with other signals such as vibratory signals previously. Here, we investigated multimodal signaling function in the visual and substrate-borne vibratory modalities of the UV-ornamented jumping spider Cosmophasis umbratica, in which the importance of UV coloration in courtship displays has been demonstrated. We first described vibratory signals produced by courting males. We found that while vibratory signals mainly consist of palp drumming and abdomen thump, amplitude of abdomen thump shows a high variance and is positively correlated with body mass. This suggests that abdomen thump as a vibratory component may be condition-dependent. To examine whether the vibratory and UV signal function as backup to each other in a variable environment (efficacy-based backup hypothesis), we used a fully crossed 2 × 2 mating assay, a signal-isolation approach, to investigate how isolated and combined signals affect mate choice by females. Our results showed that both signals in isolation or in combination result in similar female responses (i.e., mating success, latency to copulation, female attention ratio). The presence of both vibratory and UV signals affects mating frequency, with no significant differences in mating frequency when vibratory and UV signals are presented in isolation or in combination. These results support the efficacy-based backup hypothesis. We therefore conclude that vibratory and UV signals have equivalent effects in predicting mating success in C. umbratica.
... Male C. umbratica will court females under full-spectrum light, but ignore females that lack UV, suggesting that palp fluorescence may be an important signal for species recognition or mate choice that could indicate female quality or attract the attention of males (Clutton-Brock, 2009). In Singapore, males are sometimes more abundant than females but at other times of the year there are more females than males inhabiting the leaves and flowers of tropical 'sun-loving' flowering shrubs in open areas (Li, n.d.;Lim & Li, 2004). This suggests that the sex ratio is dynamic, making mutual mate choice possible in this species. ...
... This suggests that the sex ratio is dynamic, making mutual mate choice possible in this species. In the laboratory, male C. umbratica can mate multiple times (Li, n.d., Lim & Li, 2004) and males often copulate by engaging one of both or their palps for insemination (Lim & Li, 2004). These behaviours suggest that sperm supplies may be depleted by frequent mating, driving selection on males to be choosy of condition-variable females (Wong & McCarthy, 2009). ...
Article
Male ornaments, commonly explained as being a result of sexual selection, are typically more elaborate than female ornaments. Interestingly, the bright and showy sexually selected traits of some female ornaments, like those of males, might be variable and condition dependent, and hence relate to individual quality. Ultraviolet (UV)-induced fluorescence is one such ornament known to be intricately involved in intraspecific communication in several animals; however, the role of fluorescence in signalling individual quality is unknown. The ornate jumping spider, Cosmophasis umbratica, exhibits female-specific UV-induced fluorescence on its palps to facilitate effective intersex communication but whether the fluorescence informs males of the female's condition and individual quality is unknown. We tested the prediction that UV-induced fluorescence in adult female C. umbratica depended on postmaturation age, mating status and feeding regime. We found that postmaturation age and feeding regime, but not mating status, affected female fluorescence. Middle-aged females were brighter than younger and older females, but the older females had a greener hue; well-fed females were brighter than starved females. We conclude that the UV-induced fluorescence of female C. umbratica is highly condition dependent, highlighting the importance of considering female as well as male ornamentation, particularly when this may have implications for mate choice and the maintenance of coloration in animals.
... Our results contrasted with the general pattern amongst spiders regarding their body size because adult spider males are often smaller than females (Head 1995). Though a few exceptions with a reversed pattern exist e.g. in salticids (Prenter et al. 1999;Lim and Li 2004), the adult males of the species studied here are also smaller than the adult female conspecifics (Kim and Lee 2014). One possible explanation for our findings could be that the female sample collected in autumn comprised proportionally more antepenultimate individuals than the male population. ...
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Selection forces often generate sex-specific differences in various traits closely related to fitness. While in adult spiders (Araneae), sexes often differ in colouration, body size, antipredator or foraging behaviour, such sex-related differences are less pronounced amongst immatures. However, sex-specific life-history strategies may also be adaptive for immatures. Thus, we hypothesized that, among spiders, immature individuals show different life-history strategies that are expressed as sex-specific differences in body parameters and behavioural features, and also in their relationships. We used immature individuals of a protandrous jumping spider, Carrhotus xanthogramma, and examined sex-related differences. Results showed that males have higher mass and larger prosoma than females. Males were more active and more risk-tolerant than females. Male activity increased with time, and larger males tended to capture the prey faster than small ones, while females showed no such patterns. However, females reacted to the threatening abiotic stimuli more with the increasing number of test sessions. In both males and females, individuals with better body condition tended to be more risk-averse. Spiders showed no sex-specific differences in inter-individual behavioural consistency and in intra-individual behavioural variation in the measured behavioural traits. Finally, we also found evidence for behavioural syndromes (i.e. correlation between different behaviours), where in males only the activity correlated with the risk-taking behaviour, but in females all the measured behavioural traits were involved. The present study demonstrates that C. xanthogramma sexes follow different life-history strategies even before attaining maturity.
... Recognition of jumping spiders by jumping spiders. Many studies support the general idea that salticids visually recognize other salticids either as prey (Nelson & Jackson 2007;Dolev & Nelson 2014;RoQ ßler et al. 2021), as a rival (Faber & Baylis 1993;Lim & Li 2004), or as a conspecific (Clark & Uetz 1990;Nelson 2010;Girard, Kasumovic & Elias 2011). The relative position of the legs of an sighted object appears to be a relevant feature (Dolev & Nelson 2014). ...
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This article introduces the concept of a salticid archetype for salticid spiders, and provides many examples of how this archetype is expressed in scale patterns on the wings of Lepidoptera.
... Here, one insect (Gryllus campestris) and one spider species (Cosmophasis umbratica) showed a non-significant trend toward younger males exhibiting higher sexual trait expression than older ones, possibly through trait deterioration. Indeed, male C. umbratica tend to fight (Lim and Li 2004), which could result in the loss of scales affecting body colouration in older males (Lim and Li 2007). Similarly, the wings in G. campestris, which males use to produce their courtship calls, may also deteriorate over time (Jacot et al. 2007). ...
... Many insects display an image that suggests the appearance of a salticid spider as viewed from the front. In some cases this display also includes movement suggestive of the aggressive or agonistic displays of these spiders (e.g., Lim & Li 2004;Hill 2018). Here we review a series of examples that may represent predator mimicry, or the mimicry of predators, in this case salticid spiders, by their prey. ...
Article
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Many different insects appear to mimic the appearance of the salticid spiders as viewed from the front. Examples of this mimicry are reviewed with respect to the hypothesis that these are examples of predator mimicry, whereby salticid spiders are less likely to attack prey that present images of other salticid spiders.
... The behaviours of the males were video recorded. We played back the videos and recorded the winner and loser for each contest (i.e. based on whichever individual 'decamped' first; Lim & Li, 2004). The prior experience with fighting gained by the males that were reused (i.e. the contest outcome of an individual's previous contest; Kasumovic, Elias, Punzalan, Mason, & Andrade, 2009) was recorded to control for the effect of experience in the subsequent statistical analyses. ...
Article
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Consistent interindividual differences in behaviour (i.e. personality) and intraindividual variability in behaviour (higher intraindividual variability means lower behavioural predictability) are common across animal taxa. However, how personality and behavioural predictability of males and females influence female mate choice and maleemale competition remains poorly understood. Here, we investigated this in the jade jumping spider, Siler semiglaucus. After assessing the level of aggression (an individual's average aggression) and aggression predictability (the variability around average aggression within an individual) of both S. semiglaucus males and females, we performed female mate choice trials to test whether aggression and aggression predictability in females, males or both would affect female mate choice. We also conducted male contest trials to test whether male aggression or aggression predictability would influence the outcomes of male contests. We found that both females and males showed consistent interindividual differences in aggression, and aggressive spiders were more predictable than less aggressive ones. Despite a positive correlation between aggression and predictability, male aggression predicted female mate choice better than aggression predictability. Females showed a directional preference for aggressive males over docile males regardless of female aggression or male aggression predictability. Predictable aggressive males were also more likely to win contests. Our results suggest that both female mate choice and maleemale competition favour males with high aggression, and thus total sexual selection that acts on male aggression may be reinforcing. These findings also highlight that male S. semiglaucus with a higher level of aggression may have better reproductive performance.
... Jumping spiders (Family Salticidae) are a particularly intriguing system in which to study polymorphism because sexual selection and predation risk are closely intertwined as males often court larger (potentially cannibalistic) females that can be either mates or predators (Richman and Jackson 1992;Jackson and Pollard 1997). Jumping spiders have been extensively studied for their species-specific male courtship displays and elaborate coloration and ornamentation; such male displays have been hypothesized to mediate male-male interactions (Jackson and Cooper 1991;Lim and Li 2004;Tedore and Johnsen 2014) or to provide honest information used in female choice (Lim et al. 2008;Sivalinghem et al. 2010;Taylor et al. 2011;Taylor and McGraw 2013). Sexual cannibalism, where females consume males either before or after mating, is also prevalent among many jumping spider species and likely plays a large role in the mating strategies of males (Richman and Jackson 1992;Jackson and Pollard 1997). ...
Article
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Polymorphism can arise across taxa due to various selection pressures and potentially lead to alternative mating or antipredator strategies. For male jumping spiders, sexual selection and predation risk are often intertwined when courting cannibalistic females and may be a driving factor in the polymorphism of the jumping spider, Maevia inclemens. The dimorphic males of M. inclemens differ dramatically in their complex courtship behavior and display traits that may function as alternative mating strategies to reduce female aggression and maximize mating success. We hypothesized that males of the “tufted” morph honestly communicate condition or body size to females with three conspicuous tufts of setae on their head and males of the “striped” morph reduce female aggression with coloration commonly found in aposematic animals (here, yellow-orange pedipalps and striped legs). We examined correlations between tuft length and symmetry and metrics of body size and condition in field-collected spiders and conducted prey color choice tests (with live color-manipulated prey) to determine if yellow-orange and striped prey are avoided. Tuft length was variable and correlated with male size (but not condition). All prey color types were attacked at equal rates, but spiders oriented to striped prey more often, suggesting that male stripes may attract female attention without increasing predation. This study provides insight into the potential functions of the different courtship and visual displays of M. inclemens males. Using jumping spiders to study polymorphism can provide new insight into how multiple morphs can evolve, as males use mating strategies not only to impress females but also avoid getting eaten by their potential mates. Significance statement Understanding the selection pressures that shape and maintain polymorphisms in natural populations is an active area of inquiry, yet most of what we know comes from a small handful of well-studied vertebrate taxa. The unique biology of jumping spiders and the fact that males have to avoid cannibalism during courtship, makes them well-suited to provide novel insights into the functions and maintenance of dimorphic male traits. The unusual male dimorphism of M. inclemens captured the attention of naturalists as early as the 1800s, yet we still do not understand why the two male morphs differ so dramatically in morphology and courtship behavior. Here, we propose and test a novel hypothesis that provides insight into the long-studied but still largely unexplained phenomenon of male dimorphism in this species.
... When navigating their surroundings, jumping spiders are able to return to overnighting nest sites with the help of beacon-nest associative learning in both real (Hoefler & Jakob, 2006) and virtual environments (Peckmezian & Taylor, 2015). Male jumping spiders also famously engage in elaborate courtship displays to females (Clark & Uetz, 1993;Elias, Maddison, Peckmezian, Girard, & Mason, 2012;Girard, Kasumovic, & Elias, 2011;Lim, Li, & Li, 2008;Taylor & McGraw, 2013), and ritualized contest displays to rival males (Lim & Li, 2004). Both sexes often engage in complex intraspecific signaling, a phenomenon particularly prominent in ant-mimicking jumping spiders who must distinguish themselves from their ant models when interacting with conspecifics (e.g., Nelson & Jackson, 2007). ...
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Many arthropods exhibit flower-visiting behavior, including a variety of spider species. However, as spiders are assumed to be strictly predatory, flower-visiting spiders are an often neglected group. We conducted a systematic biodiversity study of flower-visiting spiders based on published papers and field surveys. Most previous studies have focused on the herbivorous behavior of flower-visiting spiders (nectivory or pollinivory) and their effects on host flowers (tritrophic interactions with flower-visiting insects). In our field survey, we utilized standard transect walks (active sampling) and colored pan traps (passive sampling) to investigate species occurrence, diurnal and seasonal variation, and flower color preference of flower-visiting spiders. From the transect walks, crab spider species were found to be the dominant flower-visiting spiders and, based on all spider species, juvenile visitors were significantly more common than adults. Furthermore, in terms of spider number and species richness, tulips were the preferred flower to visit. For the pan traps, wolf spiders were found to be the dominant spider species. No significant differences were observed in the number of spiders caught in different colored pans, suggesting that color may not be an important flower trait in regard to spider preference. To the best of our knowledge, this study is the first to propose the term 'flower-visiting spiders' and conduct a systematic investigation of their diversity. However, this is preliminary research and further studies are required, especially as biodiversity is often closely linked to survey sites and ecotopes.
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The spider fauna of Singapore has never been studied in its entirety despite of contributions by many arachnologists since Koch in 1843. In the present paper, we provide a preliminary checklist of spiders from Singapore based on published records, on the collections of the Raffles Museum of Biodiversity Research (RMBR), National University of Singapore, and on specimens collected by the authors and by D. H. Murphy. A total of 310 species and one subspecies (Uloborus undulatus indicus Kulczy ski, 1908) of spiders are now recorded for Singapore. They belong to one suborder (Opisthothelae), two infraorders (Mygalomorphae and Araneomorphae), 39 families and 186 genera. Among them 29 new records and 14 unidentified species are listed; one species of zodariid, Storena cinctipes Simon, 1893, is transferred to the genus Mallinella. A very small group of species (c. 2%) exhibits cosmopolitan distributions but the majority of species are widely distributed in South-east Asia. A small group of species (c. 3%) shows pantropical distributions. Another small group of species (c. 25%) is recorded, so far, only in Singapore and nowhere else in South-east Asia. The latter figure appears linked to collecting and study efforts rather than a reflection of the real situation in the region.
Chapter
Of all the families of spiders, the Salticidae or jumping spiders undoubtedly possess the finest eyesight (Homann 1928, 1971; Land 1969a, b, 1972, 1974 and Chap. IV, this Vol.)
Article
1. 'Persistence' is defined as male courtship duration during interactions in which females failed to mate. Males of P. johnsoni were collected from habitats with differing climates, and their persistence was compared in the laboratory. 2. Beach habitats (California, sea level, ca. 100 m from the ocean) had a constant mild climate compared to the Coastal Range (California, 400-900 m elevation). Alpine habitats (Wyoming, 3,000 m) were intermediate. 3. The mating season (months during which adult males and females were simultaneously present) was shortest in the Coastal Range (2 months), longest in Beach populations (8 months), and intermediate in the Alpine population (3-4 months). Interpopulational variation in phenology seems related to differences in local climate. 4. Coastal Range males were the most persistent (mean, 3.3 min); Beach males were the least persistent (1.9 min); and Alpine males were intermediate (2.7 min). This trend seems to be related to interpopulational variation in phenology.