Phidippus princeps ( Peckham & Peckham 1883 )
treatment provided by
|Phidippus princeps ( Peckham & Peckham 1883 )|
Attus insolens Hentz 1845 , nomen nudum by Edwards 2004
Phidippus brunneus Emerton 1891 , synonymy by Bryant 1942
Edwards (2004) also charted a gap between the ranges of the two species, with P. pulcherrimus restricted to the coastal plain below the fall line from Alabama to Georgia and P. princeps more widely distributed in the eastern forests from southeastern Canada west to the Great Plains ( Figures 1-2 View Figure 1 View Figure 2 ). The female P. dorsalis Bryant 1942 View in CoL (Southern Pines, North Carolina), bearing a distinctive middorsal stripe on the opisthosoma, was recognized as a southern form of P. princeps .
To further assess the relationship of princeps and pulcherrimus I have collected, reared, observed behavior, and photographed princeps group spiders representing a series of local populations that span the gap between the two species in the southeastern United States, ranging from northern South Carolina to central Florida ( Figure 1 View Figure 1 , populations 1-10).
A series of adult or immature representatives of the southeastern populations enumerated or identified with a B (based on photographs by Beaton) in Figure 1 View Figure 1 are presented here in a series of figures ( Figures 3-37 View Figure 3 View Figure 4 View Figure 5 View Figure 6 View Figure 7 View Figure 8 View Figure 9 View Figure 10 View Figure 11 View Figure 12 View Figure 13 View Figure 14 View Figure 15 View Figure 16 View Figure 18 View Figure 19 View Figure 21 View Figure 22 View Figure 23 View Figure 24 View Figure 25 View Figure 26 View Figure 27 View Figure 28 View Figure 29 View Figure 30 View Figure 31 View Figure 32 View Figure 33 View Figure 34 View Figure 35 View Figure 37 ). In general adults shown here represent individuals collected in the field and reared from the prepenultimate or penultimate stages to maturity. Earlier instars were reared after successful mating of field-collected adults from the same locality.
females from intermediate populations. 10-12, P. pulcherrimus . Photos by G. Beaton, used with permission.
Diagnostic characters. Since most individual spiders that I reared were tracked only by locality and not by individual, the exact instar could not always be determined. In these cases instar has been designated according to size and general appearance as shown in Table 1. Robertson & Stephens (2002) reared P. princeps from Macon County, Illinois in the laboratory and found that females needed 9 molts to attain maturity in the 10th instar. They suggested that males might mature earlier than females, by the 8th instar. I have found that southern spiders in this group of either sex can mature in the 8th instar. Actual instar count in the field may vary based on locality, hatchling size, climate and the length of each season.
Drawings associated with earlier descriptions of these spiders are reproduced for reference in Figure 38. View Figure 38
1. ♀ princeps (ventral, 2. ♀ princeps (ventral, 3. ♀ dorsalis (ventral, 4. ♀ princeps (ventral, 5. ♀ pulcherrimus Peckham & Peckham 1883 ) Peckham & Peckham 1909) Bryant 1942) Kaston 1945) (ventral, Keyserling 1885)
10. ♂ insolens (dorsal,
(ventral, Edwards 2004) (dorsal, Edwards 2004) (ventral, Edwards 2004) (dorsal, Edwards 2004)
County Ohio, photo by Jay Barnes) Edwards 2004) pedipalp, Edwards 2004)
A comparison of characters for each southeastern locality that I have studied (1-10), mostly related to coloration and the distribution of scales, is presented in Table 3. Many of these characters, including the brown mask of juvenile spiders, the white face of adult females, and the presence of some males lacking white bands below and behind the PLE, could be found in almost all of these populations.
Diagnosis of spiders in the Phidippus princeps group has relied primarily on coloration, scale patterns and genitalia. The distinctive female epigynum and male pedipalp have often been used to identify members of the princeps group ( Kaston 1945, 1948; Edwards 1980, 2004; Paquin & Dupérré 2003), but only Edwards (1980, 2004) has compared the genitalia of both P. princeps and P. pulcherrimus . Even without a study of variation within and between populations, the described genitalia of both sexes are quite similar and appear to pose no barrier to mating. Some P. princeps males ( Figure 38 View Figure 38 :16) may have an apex of the embolus that is just as robust as that associated with male P. pulcherrimus . Edwards (1980) was able to mate the two species. In laboratory trials that I will not detail here I have found that some males and females nominally assigned to either species will court and mate with either species. This is only an anecdotal observation, but it appears that at least some female P. princeps find the larger male P. pulcherrimus to be particularly attractive. Males and females from intermediate (hybrid zone) localities successfully mated and produced broods with fertile offspring that I reared to the adult stage. No significant mortality of either eggs or juveniles was observed with respect to these broods.
To the casual observer the bright, aposematic colors of P. pulcherrimus clearly distinguish these from the dull and cryptic colors of northern P. princeps . However, as shown here, there are many intermediate forms that can be found far beyond the hybridization zone centered just below the southeastern fall line. These include variations on the dorsalis form ( Edwards 2004) bearing a middorsal line of scales on the opisthosoma that can be found in individuals associated with both P. princeps and P. pulcherrimus populations. Comparison of juvenile with adult forms shows that while typical P. pulcherrimus retain a juvenile pattern of dorsal opisthosoma scales as they mature, this juvenile pattern tends to be replaced and obscured by a dense growth of relatively uniform or cryptic scales in the later instars of P. princeps .
Habitat. Juvenile to penultimate Phidippus princeps can be found living on herbaceous plants, shrubs, or young pine trees in open woodland or old fields, particularly in relatively undisturbed old fields or regrowth areas that border mature woodland ( Edwards 1980, 2004; Roach & Edwards 1984; Roach 1988; Baker 2007; Stankowich 2009; Sourakov 2013; Hill 2016). In the southeast I have been most successful in finding these spiders, as well as princeps-pulcherrimus intermediates, on herbs in infrequently cleared utility corridors bordering mature forest. I have also seen dense populations of P. princeps in the north (Minnesota and New York) in old fields or prairie far removed from forest, in which large shrubs or young trees were present. In field trials P. princeps were found to selectively move toward taller, greener or more grass-like targets through vegetated corridors rather than over bare ground ( Baker 2007; Baker et al. 2009). Juveniles mature in the late summer months, in the old field habitat occupied by adult female P. clarus (See Hill 2014) , which they resemble ( Roach & Edwards 1984; personal observations). It is possible that juvenile P. princeps gain some advantage during their juvenile instars through this kind of mimicry. We know little to nothing about where P. princeps overwinter and rear their young. I have observed pre-penultimate or penultimate P. princeps looking toward nearby tree trunks and then moving from herbs to those trunks ( Hill 2010a). It is quite possible that the association of this species with mature forest or at least shrubs and young trees is related to the fact that they nest in these places, away from the herbaceous plants that they inhabit in their juvenile stages.
P. pulcherrimus immatures are also inhabitants of the open woodland understory and can also be found on shrubs in old fields or other transitional (field to forest) habitats in the southeast ( Edwards 1980, 2004). They can often be found in large numbers on grass and herbacous plants near pine flatwoods in Florida in the late summer or autumn months ( Edwards 1980; personal observations). As with P. princeps View in CoL , we know very little about their oviposition and brooding sites. However Edwards (1980, 1990) reported that Jon Reiskind found one female with her egg sac in a rolled sweet gum ( Liquidambar styraciflua View in CoL ) leaf. This supports the hypothesis that princeps View in CoL group spiders, unlike P. clarus View in CoL that remain in the lower layer of herbaceous plants ( Hill 2014), leave these plants to overwinter and to nest in trees.
Nesting. Immature spiders in the Phidippus princeps View in CoL group construct flattened, tubular nests between leaves and stems of herbaceous plants, often near the top of these plants ( Hill 1977b; Edwards 1980; Figure 39). Nests have 2-4 flattened entrances that can be opened and closed.
I have also seen an immature P. princeps nest with three entrances suspended on silk lines between herbaceous plants in woodland understory of Greenville County, South Carolina. In Tompkins County, New York I found many immature P. princeps nesting in the dry umbels of herbaceous plants in an open field. Hoefler & Jakob (2006) also reported that the umbels of Queen Anne's Lace (Daucis carota) were a preferred site for nesting by P. princeps .
Nest site fidelity. Edwards (1980) described how P. pulcherrimus made short hunting forays and then returned to their nests. In Hennepin County, Minnesota, I once observed an immature P. princeps moving directly over a distance of more than 40 cm to reach its nest late in the day ( Hill 1977b). In Greenville County, South Carolina I also observed an immature P. princeps carrying a captured moth down a stem and then over to a nearby plant where its nest was concealed, covering a total distance of more than 50 cm.
Phenology. Seasonal activity of northern and southern populations must vary as the growing season in the subtropical southeast can be more than twice as long as the growing season far to the north. However longer daylight hours in the north can compensate for this somewhat and it appears that both P. princeps and P. pulcherrimus follow an annual life cycle. In South Carolina I have found abundant juvenile instars for both P. princeps and intermediate forms from mid- to late summer, followed by the pre-penultimate and penultimate stages in October. Kaston (1948) found that P. princeps in Connecticut mature from late April to early May, with adults living at least until July. Edwards (1980, 1990, 2004) reported that North Carolina P. princeps mature from April to June and lay eggs from May to July, while Florida P. pulcherrimus mature from March to April and and lay eggs from April to July. The earlier maturation of P. pulcherrimus in Florida can be associated with an earlier spring season there. In South Carolina, Roach (1988) described an even earlier maturation for P. princeps , with eggs laid from February to April and dispersal of emergent instars between 9 March and 10 July. Both species appear to share the same temporal niche, overwintering in the late stages of development to mature in the spring.
In the laboratory Robertson & Stephens (2002) reported three successive clutches for each P. princeps female, averaging 63 eggs for the first clutch and then 37 to 16 eggs in subsequent clutches. Kaston (1948) counted two clutches for Connecticut P. princeps , one of 43 eggs and the second of 115 eggs. Edwards (1980) found an average of 59 and a maximum of 61 eggs for each brood of P. pulcherrimus . Population density for these spiders can be quite high for the juvenile stages, although Edwards (1980) reported a significant drop in Florida P . pulcherrimus after instar 4. Baker (2007) noted that the population density of P. princeps in western Massachusetts can be as high as 3-5/m 2.
Predation. Spiders of the Phidippus princeps group feed on many different prey in the laboratory ( Figures 40-45 View Figure 40 View Figure 41 View Figure 42 View Figure 43 View Figure 44 View Figure 45 ). They are known as ambush predators that face downward on stems of herbaceous plants as they watch for prey ( Hill 1977b, 2010a; Edwards 1980, 1990). They will often wipe insects that secrete noxious chemicals against a leaf until those chemicals have dissipated. They reject toxic milkweed bugs ( Oncopeltus fasciatus ) that have fed on milkweed ( Asclepias ) on contact, and can learn to avoid these aposematic insects for at least several hours ( Hill 2014), but this avoidance appears to be lost with a change in location or context ( Skow & Jakob 2006). Jakob et al. (2008) also found that some individuals were skilled at associating prey locations with either red or blue colors. Long et al. (2012) found that avoidance of toxic fireflies ( Photuris ) by P. princeps could be associated with a flashing LED, suggesting that these spiders can learn to associate the flashing of fireflies with their unpalatibility. Both P. princeps and P. pulcherrimus readily find and navigate detours to reach sighted prey (Hill 1077b, 2010a), and adjust both the relative direction and velocity of their jumps to reach that prey with their fangs and outstretched legs ( Hill 2006a, 2010b, 2018). I have also seen P. princeps attempting to intercept a running ant, and conducting a tactile exploration of flower heads with their front legs ( Hill 1977b).
My field observations in Greenville County, South Carolina, suggest that small moths and conspecific spiders are frequent prey of immature Phidippus princeps . Sourakov (2013) staged encounters between the Red-banded Hairstreak ( Calycopis cecrops ) and P. pulcherrimus , resulting in unsuccessful attacks by this spider aimed at the tailed hind wings (or false head) of these butterflies ( Figure 46 View Figure 46 ), although attacks on moths of comparable size were invariably successful. Like P. pulcherrimus , C. cecrops is a common inhabitant of the forest understory in the southeastern United States.
In Greenville County, South Carolina, I have observed two instances of predation by Phidippus princeps that suggest a much greater predatory versatility for these spiders. In the first instance I found a late immature (instar 5-7) P. princeps holding a leafhopper but also trapped in the orb web of a much larger araneid (most likely Acanthepeira sp. ) on a small tree in an open field. Without dropping the leafhopper, this P. princeps fought off several approaches by the resident araneid by batting it with both legs I until able to use its mouthparts to cut itself free of the adhesive silk of the orb web and drop to the ground. In the second instance I found a penultimate P. princeps in a clearing along the margin of a mature forest, in the sunshine on top of an upper leaf of an herbaceous plant. This P. princeps was alternately macerating a mass of small flies that it had captured and rapidly flicking its pedipalps up and down to flash its iridescent green chelicerae toward the front (See Figure 19 View Figure 19 :1-4). As I watched, I saw this spider capture two more small flies in succession as they approached, both added to the mass that it was feeding upon.
Courtship and mating ( Figures 47-55 View Figure 47 View Figure 48 View Figure 49 View Figure 50 View Figure 51 View Figure 52 View Figure 53 View Figure 54 View Figure 55 ). Courtship in the Phidippus princeps group is relatively simple and follows a pattern seen in many Phidippus species. During courtship display a male faces a potential mate, holding each pedipalp to the side to expose the iridescent front surface of the chelicerae in the direction of the female. At a distance legs I are extended to either side, maximizing their width as seen by the female. As a male approaches a female legs I are brought together facing toward the front, curved with the tarsi of the two legs I closer together than the patellae. In the final approach legs I are brought even closer together and extended forward to touch the top of the carapace of the female. As they approach males generally step from side to side but the extent to which they do this, and the duration of courtship activity, appears to depend not only on the ability of vegetation to support lateral movement but also on the response of a female. A responsive female may advance slightly toward a courting male or rotate her opisthosoma to one side. Males seem to advance quickly once females stop turning to follow their sideto-side movement.
The courtship of P. princeps , P. pulcherrimus , and intermediate forms follows essentially the same course. I have not recorded details of the flicking of legs I or the movement of pedipalps during these courtship displays, but Edwards (1980) described a double flick of legs I and pedipalp movement during each cycle of advancement toward a female. According to Edwards P. princeps males hold their legs higher and also flick these with a greater amplitude as they advance than do male P. pulcherrimus . In an earlier paper ( Hill 1977a) I described the manner in which northern (Hennepin County, Minnesota) male P. princeps defended themselves with legs I from attacks by aggressive females, and the general lack of success by male P. princeps that displayed during encounters staged in the open. At the same time male P. princeps males were almost always successful when they entered the resting sac of a female to cohabit, something that could continue for several days. I have generally considered northern P. princeps to be relatively dangerous to conspecific males, but this might relate to the smaller relative size of northern males that may mature earlier than females ( Robertson & Stephens 2002), a tendency of P. princeps living in dense populations to prey on conspecifics, or simply the fact that a long over-wintering season gives northern P. princeps males a greater opportunity to cohabit with females. Any of these factors may have a basis in diverging genes as a result of selective pressures that vary throughout the range of the species.
Agonistic behavior. Agonistic encounters between males in either species resemble those that I have seen in other species of Phidippus (e.g., in P. clarus, Hill 2014 ). Staged encounters between males ( Figures 56- 57 View Figure 56 View Figure 57 ) resulted in an initial stage of display in which males reared up and extended their pedipalps even further to either side than they do in courtship, rotating each paturon laterally to expand the width of the chelicerae as viewed from the front. This often escalated to extension of the fangs and a closer approach with legs I extended fully to the sides, or even to dangerous grappling that included leg contact.
5, Positions assumed by males as they displayed to females at a distance.
1) Many shared characters, including size and detailed structure of genitalia
2) Shared dimensions of niche including seasonality and microhabitat
3) Absence of localities where both types are found without intermediates
4) Acceptance of males or females of either species by the other species
5) Presence of many fertile mixed or intermediate forms in a hybridization zone
6) The width of the hybridization zone across the southeastern United States ( Figure 1 View Figure 1 )
7) The depth of the hybridization zone, or distance at which intermediate characters can be found on either side of this zone
Hill & Edwards (2013) hypothesized the northward migration of P. princeps from the western Gulf Coastal Plain and P. pulcherrimus from a much wider Florida peninsula since the last glacial maximum (LGM, ~20Ka). The two species may have diverged when isolated during a long period (>100Ky) of continental glaciation. If this is the case, then the presence of a hybridization zone in the southeast indicates that this speciation process was underway but not completed. This corresponds to the suggestion by Hammond (1991) that secondary intergradation between differentiated populations takes place in hybrid suture zones that often correlate with past geographic isolating barriers. If true then we are now witness to the convergence of two previously divergent populations. As an alternative hypothesis, differing selection pressures in the temperate eastern forest and the subtropical coastal plain may support an on-going process of divergence or speciation. However, opposing gene flow and divergent selection regimes may also maintain a long-lasting and dynamic equilibrium between two divergent populations. In this case divergence may not result in speciation ( Nosil 2008).
Edwards (2004) suggested that the aposematic coloration of a number of Phidippus species in the southeastern United States might be associated with mutillid mimicry, driven by a greater population of mutillid wasps in that region. Bright orange to red-orange or red forms of P. audax , P. clarus , P. otiosus and P. regius can also be found in the southeast ( Figure 58 View Figure 58 ). In the temperate northern areas occupied by P. princeps , cryptic coloration may be more advantageous. Curiously a single local population of P. clarus may include a variety of both cryptic and aposematic female color morphs ( Hill 2014).
Species concepts and implications for taxonomy. The species problem in biology (What is a species?) is related to the use of many different definitions for a species (e.g., Mishler & Brandon 1976; Wheeler & Platnick 2000; Wilkins 2002; Hey 2001, 2014; Saikia et al. 2008). In fact, some writers (e.g., De Queiroz 2007) advocate the creative extension of the species concept to even more dimensions and definitions. Nonetheless a number of critical thinkers ( Mayr 1942, 1976; Chung 2003; Ghiselin 2004; Haffer 2006) have suggested that we have two basic alternatives when it comes to the definition of species:
1) Application of the biological species concept (BSC) that defines a species as a population of all individuals that are capable of interbreeding
2) Application of a typological species definition (TSD), or any similar approach that uses species to delimit a taxon irrespective of speciation
A case can be made for separate biological species when these can coexist without hybridization ( Wallace 1865; Wilson & Brown 1953; Thomson 1969; Mallet 2009). Trinomial nomenclature that incorporates the concept of subspecies was introduced to describe separate geographic populations where replacement rather than coexistence is the norm ( Mallet 2013). Mayr (1982) viewed the subspecies as a useful sorting device in collections, that is, as an index to populations that differ from each other "taxonomically." Others have also emphasized the arbitrariness of subspecies designations, particularly since each allele in a population can have its own geographic distribution ( Mayr 1942; Wilson & Brown 1953).
With respect to the naming of species in the princeps group, at least three different resolutions are possible. There are no international standards to determine which of these is a correct approach:
1) For those who wish to use species in the sense of a biological species, but eshew the use of trinomials, the presence of an active hybridization zone indicates that Phidippus pulcherrimus should be viewed as a synonym of Phidippus princeps . This approach simplifies the formal classification of intermediate forms.
2) For those who also accept the use of trinomials to classify geographically distinct forms, Phidippus princeps would become the subspecies Phidippus princeps princeps , and Phidippus pulcherrimus would become the subspecies Phidippus princeps pulcherrimus .
3) For those who prefer to retain the current separation of two typological species, no change is necessary. However this makes the naming of intermediate forms more difficult (e.g., Phidippus princeps x pulcherrimus hybrids).
Research ( Table 3). Compact in size and easy to rear in the laboratory, spiders of the Phidippus princeps group have played an important role in the study of salticid behavior. Both typological species have performed well in experiments related to navigation through the complicated three-dimensional environment that they inhabit. More recent studies have dealt with their movement through vegetation and interactions with a number of potential prey species.
reference species summary
In laboratory trials 8 of 8 males placed directly near female nests entered those nests and mated successfully. Males
Hill 1977a princeps
were frequently attacked by females outside of nests.
Hill 1977b princeps Field observations of nesting, nest-site fidelity and predatory behavior in Hennepin County, Minnesota .
Hill 1978b, 1979b, princeps and Experimental study of the integrated use of distance and direction information (idiothetic, visual and gravity-referent)
2007 2010a pulcherrimus during the indirect or detoured pursuit of sighted objectives, including prey and plant positions.
Described scale patterns of typical adult females and the three-shafted red-orange pigmented scales and the flat
Hill 1979a princeps
reflective scales on the opisthosoma of adult males.
pulcherrimus northern Florida.
Roach 1988 princeps Reported three broods of 21-60 young from February-April, dispersal from March-July in South Carolina.
Edwards 1990 pulcherrimus Described sit-and-wait predation and seasonal nesting in Alachua County, FL.
Anderson 1996 pulcherrimus
Found average metabolic rate (oxygen consumption) of 30 μL O
2/hr for 156 mg adult live mass. For salticids and thomisids metabolic rate was proportional to live mass.
Robertson & Described development of instars in the laboratory, courtship, mating and fecundity of spiders captured as immatures in princeps
Stephens 2002 Macon County, Illinois .
In trials a spider would jump faster and higher to reach prey or positions at a greater distance or a higher relative
Hill 2006a, 2010b,
princeps elevation. Just before reaching prey spiders braked on the dragline and reversed pitch, pulling the legs together in a
princeps and Described extension and retraction of foot pads and claws associated with each foot, and their respective use for
Hill 2006b, 2010c
pulcherrimus attachment to plant surfaces or for walking on and handling silk lines.
Skow & Jakob 2006 princeps In trials a change of setting (context) was associated with an increased tendency to attack aposematic prey.
Hill 2009 princeps Video study of feeding females.
Baker 2007 princeps In trials spiders preferred movement through vegetated corridors to movement over bare ground.
Jakob et al. 2008 princeps In trials some spiders became significantly better at associating prey with a red or a blue color after repeated trials.
Baker et al. 2009 princeps In trials spiders moved preferably toward taller, green, grass-like targets.
Stankowich 2009 princeps In trials larger spiders fled for a shorter distance before they turned to confront a threat.
Hill 2011 princeps Described mouth and structures of anterior digestive tract from examination of exuviae.
Long et al. 2012 princeps In trials learned avoidance of unpalatable fireflies by spiders was facilitated through association with flashing LED
2013 pulcherrimus pulcherrimus from the Florida peninsula since the last glacial maximum.
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Phidippus princeps ( Peckham & Peckham 1883 )
|Hill, David E. 2018|
|Peckham & Peckham 1909|
|Peckham & Peckham 1883|
|Peckham & Peckham 1883|
|Peckham & Peckham 1883|
|Peckham & Peckham 1883|
|C. L. Koch 1846|