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Scorpion species diversity and distribution within the Mediterranean and arid regions of northern Israel
Journal of Arid Environments (1980) 3,205-213
Scorpion species diversity and distribution within the Mediterranean and arid regions of northern Israel M. R. Warburg, Shoshana Goldenberg & A. Ben-Horin* Accepted 7 January 1980 Scorpion dispersal was observed in northern Israel. The most abundant species in the Mediterranean region was Scorpio maurus fuscus and in the bordering arid regions Leiurus quinquestriatus. Five additional species were found, of which Butothus judaicus, Nebo hierochonticus and Compsobuthus w. werneri are the most important. Scorpion species diversity was measured in selected plots. The diversity index could not be correlated with vegetation or edaphic factors. There appeared to be a better relationship with climatic factors, especiallyprecipitation. The microclimate measured within the habitats has shown significant differences in both temperatures and humidities between the Mediterranean and arid regions. This, together with the difference in precipitation, can help explain the observed dispersal patterns.
Introduction Scorpions are normally associated with life in arid regions (Cloudsley-Thompson, 1956; Hadley, 1970), although several well-known species inhabit tropical and subtropical regions. In Israel, most scorpion species inhabit arid parts (Levy et al., 1973). Very little is known about those species found in the Mediterranean region of northern Israel (Warburg & BenHorin, 1978). Climatic conditions within this region are characterized by mild temperatures and intermediate to high humidities. Precipitation occurs during a short (2-3 months) winter; in addition there is a fair amount of dew especially in the coastal region. Soils are mostly heavy black soil, Terra Rossa of various types, or Rendzina and chalk. Scorpions are found on all these soils, including some species that extend their distribution to sandy regions along the seashore. In the present study, an attempt was made to analyse species structure and diversity in the Mediterranean region and compare it with a neighbouring arid region in the Jordan Valley.
Materials and Methods Scorpions were studied in the northern part of Israel from September 1974 to March 1979. They were collected during the day from under stones and other objects, and also at night using a u.v, lamp. The latter technique was used after October 1978, as a means of checking previous findings. No significant difference could be seen between the results of these two techniques used. No additional species was added by the u.v. technique, nor did the number of specimens collected per hour vary. Species diversity was studied in nine experimental plots measuring 20 X 50 m from September 1975 until October 1976. Eight of the plots were located in the Mediterranean region and the ninth in the arid region within the Jordan Valley. Vegetation within "theplots ranged from grassland to shrub and oak-woodland. The first plot, located at Mehola in the • Biology Department, Technion Israel Institute of Technology, Haifa, Israel. 0140-1963/80/030205 +09 $02.00/0
© 1980 Academic Press Inc. (London) Limited
M. R. WARBURGj S. GOLDENBERG & A. BEN-HORIN
206
Jordan Valley (elevation 50 m), was in typical arid grassland with loess soil and about 200 mm precipitation. In the same general region, but at an elevation of 500 rn, another plot was located on the Gilboa Mountains at Maale Gilboa. This plot, within the Mediterranean region and with 500 mm precipitation, was a grassland habitat with scattered Pistacia lentiscus scrubs and a few Charob trees (Ceratonia siliqua) in between. The soil was of a Rendzina chalky soil type. The next three plots were located in the Lower Galil, at an elevation of 150-200 m with about 650 mm rainfall. The soil in these three plots was of a dark Rendzina and soft chalk type. One plot, (Allon Abba) was in oak woodland, including several large Quercus ithaburensis and a few smaller Q. calliprinos. Another plot (Allonim) was in oak parkland with several medium-sized trees of the same species: this area was heavily grazed by cattle. The third plot in this region (Basmat Tivon) was heavily grazed by goats and covered by shrubs, mostly P. lentiscus. Three additional plots were selected on Mt. Carmel at an elevation of 400-500 m in a region of 750 mm annual rainfall. The first, at Muhraqa, was covered by dense shrub cover consisting of Q. calliprinos and Laurus nobilis. The second plot, located at Bet Oren, was more patchy. There were large Q. calliprinos and P. lentiscus trees with Poterium spinosum shrubs and herbaceous plants in between. The two plots were on a red Terra Rossa soil. The third plot on Mt. Carmel was at '40-0aks' on a Rendzina and soft chalk soil. This area contained some very old Q. calliprinos trees and, in between them, a few pines (Pinus halepensis) and shrubs (P. spinosum). The last plot was located on Mt. Meron in the Upper Galil at an elevation of 900 m with 1000 mm precipitation. On a dark Terra Rossa soil, it was densely covered with oakwoodland consisting mostly of Q. calliprinos and Pistacia palaestina. In all these plots, scorpions were collected periodically, identified and counted. The diversity index used here was H = - ~ PI loge PI; where PI = proportion of each species in the sample. Temperature measurements of microhabitats were taken with a YSI Tele-Thermometer (Model 44) of ±0·5 °C accuracy using six thermistor probes. Air relative humidity was measured with a Negretti & Zambra whirling psychrometer of ±2 per cent accuracy.
Results Scorpion species distribution in Northern Israel Over 1000 scorpions were collected from the experimental plots and adjacent areas in northern Israel (Table 1). Of these, Scorpio maurusfuscus was the most abundant species, with Leiurus quinquestriatus ranking next (Fig. 1). Most of the specimens were found in the Lower Galil and Mt. Carmel regions, whereas the Gilboa Mountains, Samaria and Jordan Table 1. Scorpion dispersal in northern Israel. September 1975-March 1979 Species
Scorpio maurus fuscus Nebo hierochonticus Buthotusjudaicus LeiUTUS
quinquestriatus
Compsobuthus w. werneri Compsobuthus w.judaicus Androctonus crassicauda Scorpio maurus palmatus Total no. of specimens
Upper Galil 5 5 3 1 14
Mount Carmel
Lower Galil
Gilboa Mountains
82 35 68
197 55 92 3
73 1
72
7 6 39 73 6 1
259
424
132
5
Jordan Total no. of Valley Specimens 2 6 1 150 16 7 4 186
293 102 205 226 25 147 13 4 1015
SCORPION SPECIES DIVERSITY AND DISTRIBUTION
207
Valley each yielded lower but approximately similar numbers of specimens (Fig. 2). These data indicate that in the Mediterranean region the most abundant species was S. m. fuscus with Butothus judaicus, Compsobuthus zoerneri judaicus, and Nebo hierochonticus following in that order. L. quinquestriatus is by far the prevalant species in the arid regions. The other species found are comparatively rare. Following this general survey, quantitative analysis was carried out in nine selected plots within .these regions. Plots were selected along a climatic gradient with different vegetation patterns. l§l Upper Golil
'00
~ Corm.1
;e o
I;;:'l Lower Golll
.~
•
C81 Gllboo
• =-
7G
·•
110
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o
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;;
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:u
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o
211 20
;
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Ii:
'0 II
~
S.m.f.
~
N.h.
OJ
aJ.
L.q. C.w.J. Scorpion .p.cl..
J~
C.w.w
A.c. all\,p.
Figure 1. Proportional dispersal of each scorpion species. 100 I!Jil.S.m.f
IIIJI B. J.
;e !!. e .9
l
~C.w.J.
7!l
l:V
I
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.5
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;
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.C.w.w. 1m N.~. ~ A.c. III L.q.
&0
0
• u• •... •II
. 0
Q.
211
0
v
III
Figure 2. Scorpion species proportion in each region.
Total no. of species Total no. of specimens Number of specimens per visit Species diversity index (/l =. -l:PI loge PI)
0
1-16
0·91
1·04
0·26
1'38
6·87
0
4·63
0·89
2·33
0·63
1·22
3 8
0·75
1 10
4 103
11
2 14
29 22 30
Basmat Tivon
5 74
1
13
Allone Abba
4
54 8 4
Allonim
1 3
4 2 2
Bet Oren
22
10
'40 Oaks'
Lower Galil
7 1
4 5 1
Muhraqa
Cannel Mountains
1
3
Mount Meron
Locality
Species Scorpio maurus [uscus Nebo hierochonticus Buthotus judaicus Leiurus quinquestriatus Compsobuthus w. werneri Compsobuthus w. judaicus Androctonus crassicauda Scorpio maurus palmatus
Upper Galil
Region
0·75
2·86
3 40
2S 14 1
Maale Gilboa
Gilboa Mountains
Table 2. Scorpion dispersal within the habitats during the period September 1975-0ctober 1976
0·51
9·33
3 28
2 2
24
Mehola
Jordan Valley
8 291
117 37 63 38 1 30 3 2
Total
SCORPION SPECIES DIVERSITY AND DISTRIBUTION
209
Scorpion species diversity in selected plots
In the nine study plots, were found a total of 291 specimens of scorpions belonging to eight species (Table 2). Of these two belong to the Scorpionidae (S. m. fuscus and S. m. palmatus), one to Diplocentridae (N. hierochonticus) and the remaining five species to the Buthidae. Five of these species were abundant in the Mediterranean region, while L. quinquestriatus and C. w. werneri were found mostly in the periphery of the region, especially in the areas bordering with the arid region. Androctonuscrassicauda was rarely found and was not confined to any particular region. S. m. fuscus was the most abundant species in the Mediterranean region, found in seven of eight plots. It comprised 40 per cent of the total number of specimens collected. In two plots (Mt. Meron and '40-0aks' on Mt. Carmel), it was the only species found. Butothus judaicus comprised 21·6 per cent of the total number of specimens (see Table 2). In Israel, this species is widely distributed in the Mediterranean region. Nebo hierochonticus comprised only 12·7 per cent of the total number of specimens and L. quinquestriatus only 13 per cent. Finally, of the two subspecies, C. w. judaicus was more abundant in the Lower Galil plots, whereas C. w. werneri was much rarer and was generally found in more xeric areas. The largest number of scorpions was found at Basmat Tivon in the Lower Galil (103 specimens); scorpion diversity was also highest in this region (H = 1,38). At Allonim, 74 specimens were found, but diversity was lower because most specimens belonged to a single species (H = 0'91). Two of the Carmel plots had a relatively high diversity index (Muhraqa H = 1·16 and Bet Oren H = ]'04), although only a few specimens were found in both areas. Environmentalfactors Vegetation and edaphicfactors
The percentage of vegetation cover (PVC) has shown a positive relationship with rainfall (Table 3). The correlation between scorpion species diversity and vegetation factors was not obvious. Similarily, no good relationship could be established with edaphic factors nor with the percentage of stone cover.
Climate and microclimate The microclimate during summer and fall was of interest because this is the main activity period for scorpions. Thus temperature profiles were measured during a few days in summer (June) and fall (September) (Figs 3-6). In the Gilboa Mountains temperature profiles were intermediate between the mesic '40-0aks' and the arid Mehola plot. Temperatures were higher at Allonim than on Mt. Carmel (Figs 3-6). Table 3. Habitat factors in the plots
Region (precipitation, mm) Gilboa Mountains (500) Lower Galil (650) Carmel (750) Galil Mountains (1000)
Locality of plots
PVC(%) Woody Herbaceous plants plants >0·5m <0·5m
PSC(%) Total
Stones
Total stones Rocks and rocks
Maale Gilboa
29·0
6·9
66·4
8·0
26·0
34·0
Allonim Allone Abba Basmat Tivon '40 Oaks' Bet Oren Muhraqa
23-6 33·9 75'5 90·7 72·0 106·0
2-9 18·5 5·7 8·3 2·5
JoB
80·5 74·0 117·5 109·8 98-1 108·5
0·1 0·7 5·2 6·9 4·0
5·9 1'5 11·7 0·7 12-1 Jo7
6·0 1·5 12-4 5·9 19·0 7-7
Mount Meron
105·0
2·0
107·0
H
17·2
21·3
PVC-Percentage vegetation cover; PSC-Percentage stone cover
210
M. R. WARBURG, S. GOLDENBERG & A. BEN-HORIN
45
Ca) 40
35
U
e,
...
30
2~
20
III
18
24
08
12
18
18
06
12
06
12
Tim. Ch)
.
Figure 3. 40 Oaks.
411
Co)
Cbl
40
35
f
"-
30
211
20
..
24
08
12
18 18 TII.. CII)
Figure 4. Alionim.
24
..
SCORPION SPECIES DIVERSITY AND DISTRIBUTION
40r----------,-(0)
211
---.
(bl
35
t.... 30 25
12
18
12
18
Time (hi
Figure 5. Maale Gilboa.
(b)
(01
Jr'
40
r/,7 , / .....
~
35 u
~
....
30
i
j 6/
1/
,
25
06
12
12
18
18
Time (hI
Figure 6. Mehola, Figures 3-6. Temperature profiles taken in the microhabitat at the stations. (a) July, (b) September). A Air, above ground; • ground, in shade; 6. scorpion burrow, entrance;
o
inside burrow 9 em deep.
212
M. R. WARBURG, S. GOLDENBERG & A. BEN-HORIN
All temperature measurements inside scorpion burrows have shown a gradient from the outside towards the interior of the burrow.
Discussion and conclusions Out of a total of 19 scorpion species found so far in Israel, eight species are known from the Mediterranean region (Levy et al., 1973). Seven of these species were found in this study, the eighth is very rare. Most of the remaining species are restricted to the arid region. One arid region species (L. quinquestriatus) extends its distribution also into the Mediterranean region (Levy et al., 1970). Similarly, C. w. judaicus a more xerophilic species which is found mostly in the arid region, also extends its distribution into the Mediterranean region (Zinner & Amitai, 1960). S. m, fuscus is by far the most characteristic species of the Mediterranean region. This species prefers areas of high precipitation, dense vegetation and deep soil. Apparently these factors also provide them with a suitable microclimate for maintaining optimal water and thermal balance (Warburg & Bcn-Horin, 1978). The deep soil enables burrowing, a factor known to be important for other species as well (Williams, 1966; Shorthouse, 1971; Hill, 1976). Lamoral (1978) found a good correlation between the' dispersal of burrowing scorpions (Opisthophthalmus spp.) and the firmness of the soil rather than with its texture or soil type. The number of S. m. fuscus was found to decline with the falling gradient of precipitation (Warburg & Ben-Horin, 1978). Thus S. m. fuscus is rarely found in the relatively dry Gilboa Mountains with 500 mm rainfall. Another species found in the Mediterranean region, although not confined to it, was N. hierochonticus. This species is occasionally found also in the arid region, both in the Jordan Valley and in the Negev desert (Rosin & Shulov, 1963). In the latter areas it is mostly found in creeks and wadis and there, under rocks, where it digs its deep burrows. No direct microclimatic measurements were taken there, although such microhabitats are known to provide suitable microclimates for other poikilotherms (Warburg, 1965). Another species, B. judaicus, is typical of the Mediterranean region of Israel but extends its distribution into the arid region as well. Being a good water conserver, this scorpion is more abundant in rocky habitats with stone terraces which provide suitable microclimatic refuges, as it is unable to dig burrows. Similar habitats were described for Urodacus abruptus in Australia (Smith, 1966). L. quinquestriatus, the most common scorpion in the southern part of the country (Levy et al., 1970), extends its distribution into the Mediterranean region, mainly in the Gilboa Mountains. It was rarely found in the Lower Galil, and appears to be restricted to areas of lower precipitation. It is much better adapted to the high temperatures and low humidity of the arid environment (Cloudsley- Thompson, 1962), as are other species of desert scorpions as well (Hadley, 1970; Shorthouse, 1971; Hadley & Williams, 1968). Thus, Hadrurus arizonensis is exposed to temperatures over 40°C within its burrows (Hadley, 1970) as is Urodacus yashenkoi (Shorthouse, 1971), and L. quinquestriatus (Cloudsley-Thoinpson, 1962). The diversity index calculated for the scorpion species in the experimental plots could not be correlated with edaphic or vegetation factors. It appears also to have no relationship to that of isopods, some of which comprise a major food source for some scorpionids and displocentrids [Warburg et al., 1978). Precipitation and other climatic factors do not appear to effect the diversity index, they may have a major effect on scorpion distribution; however the manner of this effect is not clearly understood. We have been greatly assisted in scorpion collecting by Ittai Warburg and by information from, and discussions with, Pinhas Amitai and Dr Gershom Levi, for which we are most grateful. This study was partly supported by a grant from the U.S.-Israel Binational Science Foundation (B.S.F.), Jerusalem.
SCORPION SPECIES DIVERSITY AND DISTRIBUTION
213
References Cloudsley-Thompson, J. L. (1956). Studies in diurnal rhythms-VI. Bioclimatic observations in Tunisia and their significance in relation to the physiology of the fauna, especially woodlice, centipedes, scorpions and beetles. Annals & Magazine of Natural History (12) 9: 305-329. Cloudsley-Thompson, J. L. (1962). Lethal temperatures of some desert arthropods and the mechanism of heat death. Entomologia Experimentalis et Applicata, 5: 270-280. Hadley, N. F. (1970). Micrometeorology and energy exchange in two desert arthropods. Ecology, 51: 434-444. Hadley, N. F. & Williams, S. C. (1968). Surface activities of some North American scorpions in relation to feeding. Ecology, 49: 726-734. Hill, R. D. (1976). Population ecology and adaptative biology of Paruroctonus mesaensis (Scorpionida: Vaejovidae) Ph.D. Thesis Arizona State University, Tempe. Lamoral, B. H. (1978). Soil hardness, an important and limiting factor in burrowing scorpions of the genus Opisthophthalmus C. L. Koch, 1837 (Scorpionidae, Scorpionida). Symposium of the Zoological Society of London, 42: 171-181. Levy, G., Amitai, P. & Shulov, A. (1970). Leiurus quinquestriatus hebraeus (Birula, 1908) (Scorpiones: Buthidae) and its systematic position. Israel Journal of Zoology, 19: 231-242. Levy, G., Amitai, P. & Shulov, A. (1973). New scorpions from Israel, Jordan and Arabia. Zoological Journal of the Linnean Society, 52: 113-140. Rosin, R. & Shulov, A. (1963). Studies on the scorpion Nebo hierochonticus, Proceedings of the Zoological Society of London, 140: 547-575. Shorthouse, D. J. (1971). Studies on the biology and energetics of the scorpion Urodacus yaschenkoi (Birula, 1904). Ph.D. Thesis. Pp, 163. Australian National Univ. Canberra. Smith, G. T. (1966). Observations on the life history of the scorpion Urodacus abruptus Pocock (Scorpionidae), and an analysis of its home sites. Australian Journal of Zoology, 14: 383-398. Warburg, M. R. (1965). The microclimate in the habitats of two isopod species in southern Arizona. American Midland Naturalist, 73: 363-375. Warburg, M. R. & Ben-Horin, A. (1978). Temperature and humidity effects on scorpion distribution in northern Israel. Symposium of the Zoological Society of London, 42: 161-169. Warburg, M. R., Rankevich, D. & Chasanmus, K. (1978). Isopod species diversity and community structure in mesic and xeric habitats of the Mediterranean region. Journal of Arid Environments, 1: 157-163. Williams, S. C. (1966). Burrowing activities in the scorpion Anuroctonus phaeodactylus (Wood), (Scorpionida: Vejovidae). Proceedings of the California Academy of Sciences, 34: 419-428. Zinner, H. & Amitai, P. (1969). Observations on hibernation of Compsobuthus acutecarinatus E. Sim and C. schmiedeknichti Vachon (Scorpionidae, Arachnida) in Israel. Israel Journal of Zoology, 18: 41-47.
Scorpion species diversity and distribution within the Mediterranean and arid regions of northern Israel M. R. Warburg, Shoshana Goldenberg & A. Ben-Horin* Accepted 7 January 1980 Scorpion dispersal was observed in northern Israel. The most abundant species in the Mediterranean region was Scorpio maurus fuscus and in the bordering arid regions Leiurus quinquestriatus. Five additional species were found, of which Butothus judaicus, Nebo hierochonticus and Compsobuthus w. werneri are the most important. Scorpion species diversity was measured in selected plots. The diversity index could not be correlated with vegetation or edaphic factors. There appeared to be a better relationship with climatic factors, especiallyprecipitation. The microclimate measured within the habitats has shown significant differences in both temperatures and humidities between the Mediterranean and arid regions. This, together with the difference in precipitation, can help explain the observed dispersal patterns.
Introduction Scorpions are normally associated with life in arid regions (Cloudsley-Thompson, 1956; Hadley, 1970), although several well-known species inhabit tropical and subtropical regions. In Israel, most scorpion species inhabit arid parts (Levy et al., 1973). Very little is known about those species found in the Mediterranean region of northern Israel (Warburg & BenHorin, 1978). Climatic conditions within this region are characterized by mild temperatures and intermediate to high humidities. Precipitation occurs during a short (2-3 months) winter; in addition there is a fair amount of dew especially in the coastal region. Soils are mostly heavy black soil, Terra Rossa of various types, or Rendzina and chalk. Scorpions are found on all these soils, including some species that extend their distribution to sandy regions along the seashore. In the present study, an attempt was made to analyse species structure and diversity in the Mediterranean region and compare it with a neighbouring arid region in the Jordan Valley.
Materials and Methods Scorpions were studied in the northern part of Israel from September 1974 to March 1979. They were collected during the day from under stones and other objects, and also at night using a u.v, lamp. The latter technique was used after October 1978, as a means of checking previous findings. No significant difference could be seen between the results of these two techniques used. No additional species was added by the u.v. technique, nor did the number of specimens collected per hour vary. Species diversity was studied in nine experimental plots measuring 20 X 50 m from September 1975 until October 1976. Eight of the plots were located in the Mediterranean region and the ninth in the arid region within the Jordan Valley. Vegetation within "theplots ranged from grassland to shrub and oak-woodland. The first plot, located at Mehola in the • Biology Department, Technion Israel Institute of Technology, Haifa, Israel. 0140-1963/80/030205 +09 $02.00/0
© 1980 Academic Press Inc. (London) Limited
M. R. WARBURGj S. GOLDENBERG & A. BEN-HORIN
206
Jordan Valley (elevation 50 m), was in typical arid grassland with loess soil and about 200 mm precipitation. In the same general region, but at an elevation of 500 rn, another plot was located on the Gilboa Mountains at Maale Gilboa. This plot, within the Mediterranean region and with 500 mm precipitation, was a grassland habitat with scattered Pistacia lentiscus scrubs and a few Charob trees (Ceratonia siliqua) in between. The soil was of a Rendzina chalky soil type. The next three plots were located in the Lower Galil, at an elevation of 150-200 m with about 650 mm rainfall. The soil in these three plots was of a dark Rendzina and soft chalk type. One plot, (Allon Abba) was in oak woodland, including several large Quercus ithaburensis and a few smaller Q. calliprinos. Another plot (Allonim) was in oak parkland with several medium-sized trees of the same species: this area was heavily grazed by cattle. The third plot in this region (Basmat Tivon) was heavily grazed by goats and covered by shrubs, mostly P. lentiscus. Three additional plots were selected on Mt. Carmel at an elevation of 400-500 m in a region of 750 mm annual rainfall. The first, at Muhraqa, was covered by dense shrub cover consisting of Q. calliprinos and Laurus nobilis. The second plot, located at Bet Oren, was more patchy. There were large Q. calliprinos and P. lentiscus trees with Poterium spinosum shrubs and herbaceous plants in between. The two plots were on a red Terra Rossa soil. The third plot on Mt. Carmel was at '40-0aks' on a Rendzina and soft chalk soil. This area contained some very old Q. calliprinos trees and, in between them, a few pines (Pinus halepensis) and shrubs (P. spinosum). The last plot was located on Mt. Meron in the Upper Galil at an elevation of 900 m with 1000 mm precipitation. On a dark Terra Rossa soil, it was densely covered with oakwoodland consisting mostly of Q. calliprinos and Pistacia palaestina. In all these plots, scorpions were collected periodically, identified and counted. The diversity index used here was H = - ~ PI loge PI; where PI = proportion of each species in the sample. Temperature measurements of microhabitats were taken with a YSI Tele-Thermometer (Model 44) of ±0·5 °C accuracy using six thermistor probes. Air relative humidity was measured with a Negretti & Zambra whirling psychrometer of ±2 per cent accuracy.
Results Scorpion species distribution in Northern Israel Over 1000 scorpions were collected from the experimental plots and adjacent areas in northern Israel (Table 1). Of these, Scorpio maurusfuscus was the most abundant species, with Leiurus quinquestriatus ranking next (Fig. 1). Most of the specimens were found in the Lower Galil and Mt. Carmel regions, whereas the Gilboa Mountains, Samaria and Jordan Table 1. Scorpion dispersal in northern Israel. September 1975-March 1979 Species
Scorpio maurus fuscus Nebo hierochonticus Buthotusjudaicus LeiUTUS
quinquestriatus
Compsobuthus w. werneri Compsobuthus w.judaicus Androctonus crassicauda Scorpio maurus palmatus Total no. of specimens
Upper Galil 5 5 3 1 14
Mount Carmel
Lower Galil
Gilboa Mountains
82 35 68
197 55 92 3
73 1
72
7 6 39 73 6 1
259
424
132
5
Jordan Total no. of Valley Specimens 2 6 1 150 16 7 4 186
293 102 205 226 25 147 13 4 1015
SCORPION SPECIES DIVERSITY AND DISTRIBUTION
207
Valley each yielded lower but approximately similar numbers of specimens (Fig. 2). These data indicate that in the Mediterranean region the most abundant species was S. m. fuscus with Butothus judaicus, Compsobuthus zoerneri judaicus, and Nebo hierochonticus following in that order. L. quinquestriatus is by far the prevalant species in the arid regions. The other species found are comparatively rare. Following this general survey, quantitative analysis was carried out in nine selected plots within .these regions. Plots were selected along a climatic gradient with different vegetation patterns. l§l Upper Golil
'00
~ Corm.1
;e o
I;;:'l Lower Golll
.~
•
C81 Gllboo
• =-
7G
·•
110
e o Q.
Jordon VoII.y
~
l :V
o
... o
;;
.••e..
:u
~ ~
o
211 20
;
III
Ii:
'0 II
~
S.m.f.
~
N.h.
OJ
aJ.
L.q. C.w.J. Scorpion .p.cl..
J~
C.w.w
A.c. all\,p.
Figure 1. Proportional dispersal of each scorpion species. 100 I!Jil.S.m.f
IIIJI B. J.
;e !!. e .9
l
~C.w.J.
7!l
l:V
I
~8.m.,.
.5
e .!!
;
...
;;
...
.C.w.w. 1m N.~. ~ A.c. III L.q.
&0
0
• u• •... •II
. 0
Q.
211
0
v
III
Figure 2. Scorpion species proportion in each region.
Total no. of species Total no. of specimens Number of specimens per visit Species diversity index (/l =. -l:PI loge PI)
0
1-16
0·91
1·04
0·26
1'38
6·87
0
4·63
0·89
2·33
0·63
1·22
3 8
0·75
1 10
4 103
11
2 14
29 22 30
Basmat Tivon
5 74
1
13
Allone Abba
4
54 8 4
Allonim
1 3
4 2 2
Bet Oren
22
10
'40 Oaks'
Lower Galil
7 1
4 5 1
Muhraqa
Cannel Mountains
1
3
Mount Meron
Locality
Species Scorpio maurus [uscus Nebo hierochonticus Buthotus judaicus Leiurus quinquestriatus Compsobuthus w. werneri Compsobuthus w. judaicus Androctonus crassicauda Scorpio maurus palmatus
Upper Galil
Region
0·75
2·86
3 40
2S 14 1
Maale Gilboa
Gilboa Mountains
Table 2. Scorpion dispersal within the habitats during the period September 1975-0ctober 1976
0·51
9·33
3 28
2 2
24
Mehola
Jordan Valley
8 291
117 37 63 38 1 30 3 2
Total
SCORPION SPECIES DIVERSITY AND DISTRIBUTION
209
Scorpion species diversity in selected plots
In the nine study plots, were found a total of 291 specimens of scorpions belonging to eight species (Table 2). Of these two belong to the Scorpionidae (S. m. fuscus and S. m. palmatus), one to Diplocentridae (N. hierochonticus) and the remaining five species to the Buthidae. Five of these species were abundant in the Mediterranean region, while L. quinquestriatus and C. w. werneri were found mostly in the periphery of the region, especially in the areas bordering with the arid region. Androctonuscrassicauda was rarely found and was not confined to any particular region. S. m. fuscus was the most abundant species in the Mediterranean region, found in seven of eight plots. It comprised 40 per cent of the total number of specimens collected. In two plots (Mt. Meron and '40-0aks' on Mt. Carmel), it was the only species found. Butothus judaicus comprised 21·6 per cent of the total number of specimens (see Table 2). In Israel, this species is widely distributed in the Mediterranean region. Nebo hierochonticus comprised only 12·7 per cent of the total number of specimens and L. quinquestriatus only 13 per cent. Finally, of the two subspecies, C. w. judaicus was more abundant in the Lower Galil plots, whereas C. w. werneri was much rarer and was generally found in more xeric areas. The largest number of scorpions was found at Basmat Tivon in the Lower Galil (103 specimens); scorpion diversity was also highest in this region (H = 1,38). At Allonim, 74 specimens were found, but diversity was lower because most specimens belonged to a single species (H = 0'91). Two of the Carmel plots had a relatively high diversity index (Muhraqa H = 1·16 and Bet Oren H = ]'04), although only a few specimens were found in both areas. Environmentalfactors Vegetation and edaphicfactors
The percentage of vegetation cover (PVC) has shown a positive relationship with rainfall (Table 3). The correlation between scorpion species diversity and vegetation factors was not obvious. Similarily, no good relationship could be established with edaphic factors nor with the percentage of stone cover.
Climate and microclimate The microclimate during summer and fall was of interest because this is the main activity period for scorpions. Thus temperature profiles were measured during a few days in summer (June) and fall (September) (Figs 3-6). In the Gilboa Mountains temperature profiles were intermediate between the mesic '40-0aks' and the arid Mehola plot. Temperatures were higher at Allonim than on Mt. Carmel (Figs 3-6). Table 3. Habitat factors in the plots
Region (precipitation, mm) Gilboa Mountains (500) Lower Galil (650) Carmel (750) Galil Mountains (1000)
Locality of plots
PVC(%) Woody Herbaceous plants plants >0·5m <0·5m
PSC(%) Total
Stones
Total stones Rocks and rocks
Maale Gilboa
29·0
6·9
66·4
8·0
26·0
34·0
Allonim Allone Abba Basmat Tivon '40 Oaks' Bet Oren Muhraqa
23-6 33·9 75'5 90·7 72·0 106·0
2-9 18·5 5·7 8·3 2·5
JoB
80·5 74·0 117·5 109·8 98-1 108·5
0·1 0·7 5·2 6·9 4·0
5·9 1'5 11·7 0·7 12-1 Jo7
6·0 1·5 12-4 5·9 19·0 7-7
Mount Meron
105·0
2·0
107·0
H
17·2
21·3
PVC-Percentage vegetation cover; PSC-Percentage stone cover
210
M. R. WARBURG, S. GOLDENBERG & A. BEN-HORIN
45
Ca) 40
35
U
e,
...
30
2~
20
III
18
24
08
12
18
18
06
12
06
12
Tim. Ch)
.
Figure 3. 40 Oaks.
411
Co)
Cbl
40
35
f
"-
30
211
20
..
24
08
12
18 18 TII.. CII)
Figure 4. Alionim.
24
..
SCORPION SPECIES DIVERSITY AND DISTRIBUTION
40r----------,-(0)
211
---.
(bl
35
t.... 30 25
12
18
12
18
Time (hi
Figure 5. Maale Gilboa.
(b)
(01
Jr'
40
r/,7 , / .....
~
35 u
~
....
30
i
j 6/
1/
,
25
06
12
12
18
18
Time (hI
Figure 6. Mehola, Figures 3-6. Temperature profiles taken in the microhabitat at the stations. (a) July, (b) September). A Air, above ground; • ground, in shade; 6. scorpion burrow, entrance;
o
inside burrow 9 em deep.
212
M. R. WARBURG, S. GOLDENBERG & A. BEN-HORIN
All temperature measurements inside scorpion burrows have shown a gradient from the outside towards the interior of the burrow.
Discussion and conclusions Out of a total of 19 scorpion species found so far in Israel, eight species are known from the Mediterranean region (Levy et al., 1973). Seven of these species were found in this study, the eighth is very rare. Most of the remaining species are restricted to the arid region. One arid region species (L. quinquestriatus) extends its distribution also into the Mediterranean region (Levy et al., 1970). Similarly, C. w. judaicus a more xerophilic species which is found mostly in the arid region, also extends its distribution into the Mediterranean region (Zinner & Amitai, 1960). S. m, fuscus is by far the most characteristic species of the Mediterranean region. This species prefers areas of high precipitation, dense vegetation and deep soil. Apparently these factors also provide them with a suitable microclimate for maintaining optimal water and thermal balance (Warburg & Bcn-Horin, 1978). The deep soil enables burrowing, a factor known to be important for other species as well (Williams, 1966; Shorthouse, 1971; Hill, 1976). Lamoral (1978) found a good correlation between the' dispersal of burrowing scorpions (Opisthophthalmus spp.) and the firmness of the soil rather than with its texture or soil type. The number of S. m. fuscus was found to decline with the falling gradient of precipitation (Warburg & Ben-Horin, 1978). Thus S. m. fuscus is rarely found in the relatively dry Gilboa Mountains with 500 mm rainfall. Another species found in the Mediterranean region, although not confined to it, was N. hierochonticus. This species is occasionally found also in the arid region, both in the Jordan Valley and in the Negev desert (Rosin & Shulov, 1963). In the latter areas it is mostly found in creeks and wadis and there, under rocks, where it digs its deep burrows. No direct microclimatic measurements were taken there, although such microhabitats are known to provide suitable microclimates for other poikilotherms (Warburg, 1965). Another species, B. judaicus, is typical of the Mediterranean region of Israel but extends its distribution into the arid region as well. Being a good water conserver, this scorpion is more abundant in rocky habitats with stone terraces which provide suitable microclimatic refuges, as it is unable to dig burrows. Similar habitats were described for Urodacus abruptus in Australia (Smith, 1966). L. quinquestriatus, the most common scorpion in the southern part of the country (Levy et al., 1970), extends its distribution into the Mediterranean region, mainly in the Gilboa Mountains. It was rarely found in the Lower Galil, and appears to be restricted to areas of lower precipitation. It is much better adapted to the high temperatures and low humidity of the arid environment (Cloudsley- Thompson, 1962), as are other species of desert scorpions as well (Hadley, 1970; Shorthouse, 1971; Hadley & Williams, 1968). Thus, Hadrurus arizonensis is exposed to temperatures over 40°C within its burrows (Hadley, 1970) as is Urodacus yashenkoi (Shorthouse, 1971), and L. quinquestriatus (Cloudsley-Thoinpson, 1962). The diversity index calculated for the scorpion species in the experimental plots could not be correlated with edaphic or vegetation factors. It appears also to have no relationship to that of isopods, some of which comprise a major food source for some scorpionids and displocentrids [Warburg et al., 1978). Precipitation and other climatic factors do not appear to effect the diversity index, they may have a major effect on scorpion distribution; however the manner of this effect is not clearly understood. We have been greatly assisted in scorpion collecting by Ittai Warburg and by information from, and discussions with, Pinhas Amitai and Dr Gershom Levi, for which we are most grateful. This study was partly supported by a grant from the U.S.-Israel Binational Science Foundation (B.S.F.), Jerusalem.
SCORPION SPECIES DIVERSITY AND DISTRIBUTION
213
References Cloudsley-Thompson, J. L. (1956). Studies in diurnal rhythms-VI. Bioclimatic observations in Tunisia and their significance in relation to the physiology of the fauna, especially woodlice, centipedes, scorpions and beetles. Annals & Magazine of Natural History (12) 9: 305-329. Cloudsley-Thompson, J. L. (1962). Lethal temperatures of some desert arthropods and the mechanism of heat death. Entomologia Experimentalis et Applicata, 5: 270-280. Hadley, N. F. (1970). Micrometeorology and energy exchange in two desert arthropods. Ecology, 51: 434-444. Hadley, N. F. & Williams, S. C. (1968). Surface activities of some North American scorpions in relation to feeding. Ecology, 49: 726-734. Hill, R. D. (1976). Population ecology and adaptative biology of Paruroctonus mesaensis (Scorpionida: Vaejovidae) Ph.D. Thesis Arizona State University, Tempe. Lamoral, B. H. (1978). Soil hardness, an important and limiting factor in burrowing scorpions of the genus Opisthophthalmus C. L. Koch, 1837 (Scorpionidae, Scorpionida). Symposium of the Zoological Society of London, 42: 171-181. Levy, G., Amitai, P. & Shulov, A. (1970). Leiurus quinquestriatus hebraeus (Birula, 1908) (Scorpiones: Buthidae) and its systematic position. Israel Journal of Zoology, 19: 231-242. Levy, G., Amitai, P. & Shulov, A. (1973). New scorpions from Israel, Jordan and Arabia. Zoological Journal of the Linnean Society, 52: 113-140. Rosin, R. & Shulov, A. (1963). Studies on the scorpion Nebo hierochonticus, Proceedings of the Zoological Society of London, 140: 547-575. Shorthouse, D. J. (1971). Studies on the biology and energetics of the scorpion Urodacus yaschenkoi (Birula, 1904). Ph.D. Thesis. Pp, 163. Australian National Univ. Canberra. Smith, G. T. (1966). Observations on the life history of the scorpion Urodacus abruptus Pocock (Scorpionidae), and an analysis of its home sites. Australian Journal of Zoology, 14: 383-398. Warburg, M. R. (1965). The microclimate in the habitats of two isopod species in southern Arizona. American Midland Naturalist, 73: 363-375. Warburg, M. R. & Ben-Horin, A. (1978). Temperature and humidity effects on scorpion distribution in northern Israel. Symposium of the Zoological Society of London, 42: 161-169. Warburg, M. R., Rankevich, D. & Chasanmus, K. (1978). Isopod species diversity and community structure in mesic and xeric habitats of the Mediterranean region. Journal of Arid Environments, 1: 157-163. Williams, S. C. (1966). Burrowing activities in the scorpion Anuroctonus phaeodactylus (Wood), (Scorpionida: Vejovidae). Proceedings of the California Academy of Sciences, 34: 419-428. Zinner, H. & Amitai, P. (1969). Observations on hibernation of Compsobuthus acutecarinatus E. Sim and C. schmiedeknichti Vachon (Scorpionidae, Arachnida) in Israel. Israel Journal of Zoology, 18: 41-47.