EGG LAYING IN SMOOTH 7 number produced hy. the fe male". Ve rrell ( 1984) also reductions of a population size as is the case of many noted that the majority of fe males remain unresponsive Ti·i111rus species. to male courtship for 20 days after the first insemination. This study shows that 44% of non­ ACKNOWLEDGEMENTS inseminatecl fe males eagerly fo llowed a courting male until the encl of sexual sequences. I would like to thank Dr Jan Rafit1ski fo r his guidance The prolonged receptiveness of fe males and the throughout this study and helpful comments in the successive taking up of spermatophores might have both preparation of this manuscript. I would also like to proximate. physiological and ultimate, adaptive reasons. thank Dr Neil Sanderson fo r his helpful comments on When the tubules are filled with a great number of the manuscript.

spermatozoa from several spermatophores (or from one REFERENCES large spermatophore) the fu nctioning of the sperm distribution might he more efficient. Baylis. H.A. (1939). Delayed reproduction in the spotted It seems that the amount of sperm reduces quickly in salamander. Proc. Zoo/. Soc. Lond. I09A. 243-246. females which lay eggs each day, as some time after Bell. G. (1977). The life of the smooth (1hwrus vulgaris) insemination the number of unferiilizecl eggs increases. after metamorphosis. Ecol. Monogr. 47. 279-299. This might explain the phenomenon, that the multiple Hagstrom. T. ( 1980). Egg production of newt (Triturus v11/garis and in southwestern Sweden. I. inseminated females produce on average 11.9% T cristatus) ASRA .Joumal 1-8. unfertilized eggs, while once inseminated as much as Halliday. T.R. and Verrell. P.A. (1984). Sperm competition in 31.8%. amphibians. In: Smith. R.L. (ed.). Sperm cornpelition and In this experiment some of the fe males after the Evolutio11 of Mating Systems. Academic Press. insemination with one spermatophore only produced a New York. pp. 487-508. large number of eggs which is close to a measured value Joly. J. ( 1966). Ecologie et cycle sexuelle de Salanwndra of the complete clutch size for a season (Hagstrom, salanwndra (L). These. CNRS. 1980). A similar phenomenon was observed in Rafiriski. J.N. (198 1). Multiple paternity in a natural population Ambystoma tigrinum and Desmognathus orhrophaeus of the alpine newt. Trit11n.1s alpestris (Laur.). Amphihia­ (Halliday and Ve rrell, 1984). The size of a Reptilia 2. 282. Smith. M. (1954). Collins. spermatophore is highly variable and most probably The British Amphibian and . London. depends on the level of male sexual activity. It might be Verrell. P.A. (1984). The responses of inseminated female that a large spermatophore may contain as may sperms smooth newts, Triturus vu/garis. to further exposure to as several smaller ones. males. British .Journal of Herpetology 6. 414-415. Multiple insemination can significantly increase Verrell, P.A. and Halliday, T. (1985). Reproductive dynamics of genetic variation of the progeny produced by a fe male. a population of smooth newts, Triturus v11/garis. in southern This might be especially significant for a species which England. Herpetologica41, 386-395. colonises transient environments and experiences sharp

HERPETOLOGICALJOURNAL. Vol. 2, pp. 7-18 (1992)

EGG, CLUTCH AND MATERNAL SIZES IN : INTRA- AND INTERSPECIFIC RELATIONS IN NEAR-EASTERN AND

ELIEZER FRANKENBERG1 AND YEHUDAH L. WERNER2 * 2

1Nat11re Reserves Authority. 78 Yim1eyah11 St.. 94467.lemsalem. Israel 2Depanment of Evolution. Systematics and Ecology. TheAlexander Silberman Institute of Life Sciences. The Hehrew U11iver.>ity of .Jen1salem. 91904 .Jerusalem. Israel *Author for co"espondence

(Accepted 18.5. 90)

ABSTRACT

We provide data on the fecundity of locally common Israeli reptiles, and use these data to examine current ideas on the reproductive ecology of lizards. Our methodology was selected in consideration of the acute problems of nature conservation in Israel. In the museum collections of the Hebrew University of Jerusalem and Tel Aviv University we used radiography to locate the shelled oviductal eggs of 164 fe male lizards. belonging to eleven species (Agamidae and Lacertidae). Each sample sums the species· variation over its range and over diffe rent years. Female body size. egg number and egg volume were determined. Specific clutch volumes. relative to maternal body lengths. resembled those reported in iguanid lizards from tropical America. Clutch size varied intraspecifically and. in most speci'es, correlated to maternal size. In others, egg size was more influenced by maternal size. We argue that the latter species oviposit in more stable environments than do the majority. 8 ELIEZER FRAN KENBERG AND YEHUDAH L. WERNER

INTRODUCTION The aspect of reproductive ecology most commonly studied in reptiles is the numher of eggs in a clutch The amount of energy availahle to an organism at any (Turner. 1977; Fitch, 1985). From studies elsewhere this given time is fi nite; the amount expended may he numher is known to vary intraspecifically hetween partitioned into mainlenance, growth and reproduction. populations (Kramer, 1946; Fitch, 1985). In some In lizards the allocation of energy to reproduction has species. clutches are larger in warmer parts of the heen reviewed hy several investigators. The main areas specific range; this results in part fro m the variation in of concern have heen. first. whether and what fe male size. larger fe males producing larger clutches diffe rences in parental investment exist hetween species (Oliver. 1955; Fitch, 1970). But in a majority of wide­ differing in hody size. hody shape. environment or ranging new-world species clutches are larger in cold hehaviour. and how such diffe rences may he explained. latitudes (and high altitudes), allegedly in compensation forthe smaller number of clutches in the shorter season (Turner. 1977). Nevertheless Vitt and Price ( 1982) listed several reports in which also the size of the eggs had been considered. These authors calculated the relation of clutch mass to parent mass, and concluded that this relation diffe rs hetween ecological types and hetween fa milies. The accuracy of some of the data and hence the validity of some of the conclusions have since heen questioned hy We rner (1988). Dunham, Miles and Reznick (1988) analyzed the relations among clutch size, relative clutch mass and foraging mode in reptiles and found that active foragers produce significantly smaller �' clutches than sit and wait foragers, with significantly 1''"1''''1" '1''' '''\�l''''I� '''' smaller relative clutch mass. They also found a relation 1 2 3 t.. s r, 7 0 9 between clutch size and : fossorial (burrowing)

Fig. I. A typical small deser1 lacer1id , guttulata. lizards produced the smallest clutches, arboreal and and her freshly laid (modal) clutch of four eggs (female arenicolous (sand-dwelling) lizards produced larger collected in the Judean on 5.IV. 1981. oviposited and clutches and terrestrial and saxicolous (rock-dwelling) photographed on 12.IV.81; from Kodachrome diapositive). lizards produced the largest clutches. Little is known of the reproductive ecology of Israeli reptiles, as, with the exception of a fe w species, mostly For example, species of lacertid lizards (Fig. 1) have venomous and gekkonid lizards (Mendelssohn, been characterized by clutches which range from 14 to 1963, 1965; We rner, 1965, 1966a, 1986a, 1988; Dmi'el, 40% of the pregnant fe male's weight. And second, how a 1967; Orr, Shachak and Steinberger, 1979), knowledge is fe male with limited energy available for reproduction limited to the scanty information in local general texts reaches a compromise between emphasizing either egg (Margolin, 1959; Werner,1966b, 1973; Arbel, 1984; Dor, number or energy content per egg. The latter value is 1987). roughly, though not precisely, paralleled by egg mass In this paper we examine the relationships among and size (Tinkle, 1969; Ballinger and Clark, 1973; clutch size, egg volume, clutch volume and maternal Emlen, 1973; Ballinger, 1978; Vitt, 1978; Huey and size, in eleven common oviparous Israeli lizards in Pianka, 1981; Vitt and Price, 1982; Fitch, 1985; Pianka, which clutch size is variable. Our aims are, first, to 1986). provide basic data about the fecundity of Israeli reptiles. Several factors affe ct the apportionment of energy in Such information is necessary (though insufficient) for egg production, since natural selection should result in the planning of nature conservation. Second, to an energetic compromise that maximizes the parent's examine some of the currently prevailing total (long-range) contrihution to future generations. generalizations (quoted above) concerning the Larger eggs may be more resistant (especially to reproductive ecology of lizards. drought) during incubation (Ackerman, Seagrave, Dmi'el and Ar, 1985). They give rise to larger young MATERIALS AND METHODS (Ferguson, Brown and DeMarco, 1982; We rner, l 986a, 1988), which are able to utilize a broader range of food SPECIES items, more ahle to withstand a shortage of food, and Gravid fe males of eleven lizard species (agamids and compete better in social encounters (Fitch, 1970; lacertids) were examined. These are listed in Ta hle 1, Fe rguson et al., 1982; Rand, 982). On the other hand, a I which details their fu ll specific, and, where applicahle, low level of competition, or a high level of predation of suhspecific, names. Most of these species have heen a type not affected hy juvenile size, may press for a heautifully descrihed and depicted in Anderson (1898). strategy of producing many small eggs. The production For the others (and some of the same) the reader is of large numhers of small eggs may he adaptive also in referred to Barash and Hoofien (1956), Ba�oglu and coarse-grained patchy environments (Emlen, 1973) or in Baran (1977), Arnold, Burton and Ovendon (1978) and those changing in time. As the environment hecomes Arhel (1984). The of the Agamidae has heen less stable, selection favours greater fecundity rather reviewed hy We rmuth ( 1967) and that of the genus than survivorship (Cody, 1966). hy Salvador (1982) and Arnold (1983). EGG RELATIONSHIPS OF LIZARDS 9

Species and subspecies World Distribution Annual rainfall Average monthly Simplified sampled Distribution in Israel (mm) (lsohyet August temperature summary of habitat of the species ranges of drought ( QC) year/wet year) (isotherm range)

Agamidae

Agama pa/Iida pa/Iida E Egypt & Wl1ole Negev 0-150/0-400 24-32 Desert and Steppe: Reuss, 1833 SW except sand dunes

Agama savign ii E Egypt. N Sinai N Negev 0- 100/100-250 26-28 Semi-desert: sands Dumeril & Bibron. 1837 & S Israel Agama sinaita NE & S Negev 0-100/0-250 28-34 Extreme desert: Heyden. 1827 SW Asia rocks

Agama stellio SE , Countrywide 50-900/200-1400 20-28 (lsr) Mediterranean and (Linnaeus. 1758) sspp. N Egypt & except most of semi-: roe ks. SW A5 ia S Negev tree trunks and buildings Lacertidae Acalllhodactylus boskianus asper N Africa & Whole Negev 0- 100/0-300 26-34 Desert and Steppe: (Audouin, 1829) SW A5ia sands. shingle etc Acanthodactylus pardalis N Africa & N Negev 0- 150/ 1 50-400 26-28 Steppe: loess soils (Lichtenstein. 1823) S Israel

Acanthodactylus schreiberi S Turkey to Mediterranean 100-600/500- 1000 24-28 Meditternnean: syriacus Boettger. 1879 N Israel coastal plain sands and light soils Aca11thodac1y/11s scwe/latus N Africa & N Negev & 0-300/250-800 26/28 Semi-desert and scute/latus (Audouin, 1829) SW Asia S Mediterranean Mediterranean; coastal plain sand dunes

Lacerta Jaevis Turkey to Countrywide 300-900/700- 1400 20-28 Mediterra nean; Gray 1838 N Israel N of Hebron scrub. gardens etc Mesa/ina guuu/ata gullulata N Africa & Wliole Negev & 0- 100/0-400 26-34 Desert and Steppe; (Lichtenstein, 1823) SW Asia S Jordan Va lley except sand dunes elegans SE Europe & N Negev & 50-900/200- 1400 20-30 Mediterra nean and (Menetries, 1832) sspp. W Asia northwards Steppe; open except sand dunes & sheer rocks

TA BLE I. Habitats of species studied (sources explained in the text).

We emphasize that our material of A. boskianus excludes SAMPLES the sibling species A. op heodurus Arnold, 1980 (Werner, Lizard eggs are not truely cleidoic (closed to water 1986b). fl ux). Depending on the conditions they may decrease Specific distributional and environmental data are or increase in mass and dimensions fairly rapidly after condensed in Ta ble I from the following sources: Wo rld oviposition (Fitch and Fitch, 1967; Packard, Tracy and distribution - Flower (1933) and Werner (!966b), and, Roth, 1977). Therefore it is difficult to base a for Agama pallida, Haas and Werner (1969); Distribution comparative study of egg size on laid eggs (although dry in Israel - Werner (1966b) and, especially, Wahrman weights and caloric values could be substituted). We ( 1970) who presents approximate distribution maps for preferred to use eggs inside oviducts of fe males already all the species except Lacena laevis; Annual rainfall - preserved in collections. a policy which also appeared relevant isohyet ranges between rainfall maps (Atlas of particularly desirable from the point of view of nature Israel 1970) for the drought year 1946/47 and the wet conservation, an acute problem in the small natural year 1944/45 (the potentially rainy season extends from areas of Israel (Ashkenazi, 1987; Frankenberg, 1989). September through May); and average monthly August temperatures - relevant isotherm ranges in an Atlas of Israel (1970) map averaging the ten years 1940- 1949. Finally, the simplified summary of the habitats is based on Wahrman's (1970) classification of types of animal distribution in Israel and data in We rner (1966b) augmented by our personal knowledge. 10 ELIEZER FRAN KENBERG AND YEHUDAH L. WERNER

ra N v

Species n x CV x CV x CV RP

Agamidae

A. pal!ida 17 78.8 8 9.4 34 0.63 30 II-VIII 67.5-85 1-12 0.36-1.06

A. savignii 2 70.5 15 4.0 35 0.86 5 63-78 3-5 0.89-1.01

A. sinaita 4 76.4 3 5.3 9 0.86 51 V-VIII 73-79 5-6 0.42- 1.46

A. stel!io 18 111.1 II 7.7 23 1.29 37 I-VII 92- 130 5-12 0.80-2.68

Lacertidae

A. boskianus 15 60. 1 7 4. 1 27 0.32 31 IV-VI 54.5-67 2-7 0. 1 8-0.49

A. pardalis 23 66.0 7 4.8 25 0.36 25 Ill-VII 59-74 3-7 0.20-0.53

A. schreiberi 10 69.0 7 2.6 31 0.53 21 IV-IX 58-75 1-4 0.32-0.69

A. scutel!atus 13 52.2 9 2.7 30 0.32 19 111-X 40-58 2-4 0.23-0.43

L. laevis 16 61.9 8 4.5 33 0.28 29 II-VII 55.5-7 1 2-7 0. 16-0.41

M. g111111lata 38 46.8 7 4.4 27 0. 14 21 II-IV 40-54.5 2-7 0.09-0.20

0. elegans 8 48.l 6 4.0 53 0.09 33 V-VIII 45-52 2-8 0.05-0. 11

TABLE 2. Basic reproductive data for eleven lizard species. Averages (x). coefficients of variation (CV) and (underneath) ranges, of body length (ra). number of oviductal shelled eggs (N) and egg volume in cm3 (V). for each of the species. RP. reproductive (oviposition) period of the species in months; and n is the number of fe males yielding data.

All the preserved lizards of relevant species in the Our material had been preserved fa irly uniformly for all National Collections (Hebrew University of Jerusalem species (mothers fixed in 10% fo rmalin, stored in 70% and Te l-Aviv University) were inspected. These had ethanol for periods usually > 1 yr) and our study been collected during many years and over all seasons. involved mainly the interspecific comparison of Fe males apparently gravid were radiographed for intraspecific traits; hence we deem the technique verification as explained below. The ensuing sample adequate. We observed no obvious collapse of the sizes (numbers of fe males yielding data) varied from 2 eggshells as noted hy Rand (1982). to 32 per species (total 164) and are given in Ta ble 2. Each suspected gravid fe male was radiographed These individuals originated. in principle. from (Softex type E X-ray machine and Ilford Industrial G throughout the specific ranges in Israel and Sinai, with fi lm) to fi nd out whether it contained shelled (or other emphasis on the former. However, of three species oviductal) eggs. We initially tested whether material from neighbouring countries was available and measurements of eggs on the X-ray plate were reliable, included: Agama pallida, Syria; L. laevis, Lebanon by comparing a sample to measurements of the same (Bayrut only); 0. elegans, Cyprus and Turkey. eggs after dissection. Fig. 2 shows that in the case of radiographs. considering the egg as representing an DATA COLLECTION AND ANALYSIS ellipsoid, as done hereinafter with the direct Our technique involved the calculation of egg measurements of the eggs, would yield a somewhat volumes from linear measurements of preserved shelled poorer approximation than regard ing the egg as an eggs. irregular sphere, with a diameter averaged between

Va rious distorting effects of fixation and storage in length (L) and width (W), using the equation V = 4/3 formalin and alcohol on the relative weight of lizard 7r [(L+ W)/4] 3. Although' approximations of egg sizes eggs have been described (Martin, 1978; Vitt, Howl and could he obtained radiographically in this way if and Durham, 1985). Guillette, Rand, DeMarco and dissection were precluded, we considered the inaccuracy Etheridge (1988) even fo und that the weight of eggs excessive and employed only direct measurement of preserved after removal from their mother hy dissection, oviductal eggs in opened bodies. is reduced during fixation hy a third as a stable fa ctor. EGG RELATIONSHIPS OF LIZARDS 11

5 . Ballinger, Fitch. including those of enriched � . I • o 0 food supply through above-average rainfall in xeric > . . 0 habitats (Turner, Lannom, Medica and Hoddenhach . • • 0 0 0 ' .4 - 1969). c.'.) . - R2= Rather, by combining all data, we derived the - 0 .720+ 12. 25 c.'.) ·" - � w ' average characterizations of the specific clutch . • ,0 0 0 ... .3 ' • J 0 Q. ' parameters, and approximate limits of their extreme t � ,' 0 9' 0 variation in the area concerned (constrained, as ranges o ' ,'�o 2 ..;/' 0 . , o o are, by sample size). Geographical variation remains to .. 0 � . ..°" tt i � 0 he treated. t' , 0 .1 - The body space a lizard can devote to carrying eggs is e o�· ..o . 0 limited. Species-specific clutch volume (species-specific V x N fro m Ta ble 2) was significantly correlated .2 .3 .4 .5 .6 .7 (interspecifically) to body size (Fig. 3). Viewing clutch volume as if it were packed in a sphere, its diameter EGG VOLUME, cm3 DISSECTIONS maintained a quite constant proportion to specific body length: 23.5 ± 3.2 percra (percents of ra - We rner, Fig. 2. The correlation of egg volumes (cm3) based on the 1971) with no significantdeviations from the mean (Chi measurement of radiographs (R) and calculated in either of two square test) (Fig. 4). Therefore, on spatial grounds, any manners, to the volumes of the same eggs derived from attempt by one of these species to increase egg volume measurements in dissections (D). In the first regression, R1 is calculated from the formula for an irregular sphere, R1 =4/ would have to be compensated by a decrease in egg 37f l(L+W)/413= l.37D-71 .4; in the second, Ri is calculated from number (per clutch), and vice versa. that of an ellipsoid, Ri=4/37f(L W2/8)=0.71D+ 12.25. D is based M on the latter for both regressions. E v 10 ,.; � ::::> _, 9 0 > For each lizard the following data were noted: body :i:: 8 v length (ra = rostrum-anus = snout-vent, following .... ::i Werner, 1971); number of eggs in each oviduct; whether _, v 7 these were shelled; length and width of all eggs in z < lizards carrying up to four, and of four eggs in lizards w carrying a greater number; and the date and location of � 6 capture. -;,, � The volume of each egg was calculated by using the u 5 w equation V = 4/3 7f (LW2/8), where V is egg volume in "- V) mm3, L is egg length in mm, and W is egg width in mm. 4 The average volume of all eggs measured of one fe male gave the characteristic egg volume for that particular specimen. These individual averages were then averaged 3 for each species to yield the specificegg volume.

Linear and partial correlations and linear and 2 multiple regressions (Steel and To rrie, 1960) between the three variables, body size (ra) in mm (Rand, 1982), egg number (N) and egg volume (V) (average per fe male) were calculated to test the relationships between them. In all these calculations only mature, shelled, eggs were used. The length of the reproductive period and the 40 50 60 70 110

number of clutches were roughly estimated for each SPECIES' MEAN ROSTRUM-ANUS LENGTH, mm species by relating egg volumes to the dates of collection. For this purpose, immature oviductal eggs Fig. 3A. Mean clutch volume (cm3) as a fu nction of mean body were measured as well. size (mm,ra) among eleven lizard species. 12 ELIEZER FRANKENBERG AND YEHUDAH L. WERNER

E • This study : r =0.96 ; r/J = Q29ra -J.J B It is apparent from Ta hle 2 that the species could he E classified into two categories regarding egg numher and o Rand (19821 : r=0.971 r/J = 0.25ra• 0.2 8 0:.- 30 egg size. Lizards with relatively large hut fe w eggs were U.J .... Agama savig11ii. A. sinaita. Aca11thodactylus schreiheri and U.J :! A. scutellatus; whereas all the others had relatively small � , ' ,' 0 and numerous eggs (Table 2). The relation hetween the three variahles, maternal I u hody size. egg volume and the numher of eggs, is .... ::J __, 20 presented three-dimensionally for each species in Fig. 4. u (Excluded is Agama savig11ii of which the sample size z was too small.) From these figures and from Ta hle 3 it is � 9' U.J 0 , apparent that in the terms of this relation each lizard :! ,, helonged to one of fourcategories: (1) Lizards which, as

v, ' stated above, hasically have relatively numerous small u 10 ',. eggs. and which in response to increased body size U.J "- Vl strictly increase the number of eggs; Agama pa/Iida. A. stel/io. Aca11thodacryluspardalis, L. /aevis. M. guttulata, and 0. elegans. (2) A lizard which also basically has numerous eggs but which with increased maternal size increases egg size rather than egg number is Aca11thodactylus boskianus. (3) A. schreiberi, which 0 20 40 60 80 100 120 140 basically has few large eggs, further increases egg size with increasing maternal size. (4) Three other lizards SPECIES' MEAN ROSTRUM-ANUS LENGTH, mm which basically have large and few eggs are Agama sinaita which with increasing maternal size increases Fig. 3B. Mean clutch diameter derived from a clutch volume both egg number and egg size (as far as known), assumed spherical. as a function of mean body size (mm, ra), Acanthodactylus scutel/atus which revealed no significant among eleven lizard species studied herein (solid symbols) and response to increasing maternal size, and Agama savignii among thirteen iguanid species studied by Rand ( 1982) (hollow where sample size enabled no conclusions. symbols).

5 � ;:; 4

A Agama pa/Iida B Agama sinaita

r 12

= .._, 10 J

C Agama stel/io D Acanthodactylus hoskianus EGG RELATIONSHIPS OF LIZARDS 13

_, � 7 .... . � ..;:.� o- :' => � <::: 6 � <::: 5 ._<>" - '." 5 - <'.> � A <'.> ,... � J 3 .� J J Jl J '.' j J l J J

F Acanth. schreiberi E Acanth. pardalis

_,

..::.�"" · o- � .��

._<>"

er :>"" ]l l j j 1 �j J J l J

H /aevis G Acanth. scutellatus

•'

".,..'-· o- _, �

._<>" a 8 s ,..., 6 � � <::: 6 - A <'.> � ,, .. ]"ljJ J J

�.,. J < l l ... j 0 ;r_... .ro .Pc:.-...... °"c.-.,.

"<"':.°"o J"..,,. ,,._... I Mesalina guttulata J Op hisops e/egans

Fig. 4A-J. Number of eggs (N) as a multiple function of maternal body size (ra) in mm and mean egg volume (V) in cm3• for each of ten species. Each vertical bar represents the clutch of one fe male. The top of each bar represents the multiple function: the base of each bar, the relation between egg volume and maternal body length. The multiple regression fu nction for these graphs. expressing the number of eggs in a clutch (N) as a fu nction of maternal body size (ra) and egg volume (V). is respectively: A. N=0.32ra-4.65V- 12.6; B, N=0.22ra-0.92V- I0.38; C. N=0.09ra-0. 83V-l.34: D. N=0.52ra-3 1.75V-17.27: E. N=0. 1 9ra-1.3 IV-7.03: F. N=O.OSra-0. 87-0.39: G. N=4.92ra-6.76V-0.002; H. N=0.26ra-2.72V-10.84: I. N=0. 18ra-10. 1 3V-2.67: J. N=0.4ra-16.3V-15.2. 14 ELIEZER FRANKENBERG AND YEHUDAH L. WERNER

r R

Species ra-N ra-V N-V ra-N(V) ra-V(N) N-V(ra)

Agamidae

A. pa/Iida 0.60** 0.17 -0.16 0.65* 0.34 -0.95

A. sinaira 0.68 0.52 -0.24 0.97 0.96 -0.31

A. stellio 0.62** 0.09 -0.19 0.65* 0.27 -0.31

Lacertidae

A. boskianus 0.42 0.52* 0.20 0.37 0.50 -0.03

A. pardalis 0.71*** 0.19 0.04 0.72** 0.23 -0. 14

A. schreiberi 0. 18 0.76** 0.09 0. 18 0.76** -0.07

A. scute/latus 0.26 -0.44 -0.61* -0.0 1 -0.37 -0.57

L. /aevis 0.76*** 0.40 0.19 0.76** 0.39 -0. 19

M guttulara 0.46** 0.23 -0. 12 0.51 ** 0.32 -0.26 0. e/egans 0.52 0.26 -0.06 0.55 0.34 -0.23

TABLE 3. Correlations between reproductive data in each of ten lizard species. Coefficients of correlation, r; and of partial correlations, R; between the three variables N, ra and V, explained and reduced in Ta ble 2. In the partial correlations the variable in parantheses is the one held constant. Significance levels indicated thus: *, P<0.05; **, P<0.01; ***, P<0.001; otherwise, the correlation is not significant.

The averages of all the species are plotted together is directed so that it is invested in enlarging the egg along the three variables (ra, N and V) in Fig. 5, which rather than increasing the number of eggs per clutch demonstrates that their mathematical interspecific (ra-V(N) = 0.92). This accords with the widespread relation in Israeli agamid and lacertid lizards, as a observation, that larger species produce larger offspring. group, is as follows. Any additional reproductive effort Ta ble 2 also indicates the reproductive months (when enabled through an (interspecific) increase in body size, fe males contained shelled oviductal eggs) per species.

Fig. 5. Mean number of eggs in each species, as a multiple function of specific (mean) body length and of specific (mean) egg volume (as in Fig. 4 . The circles represent foreach species an average SD, calculated from the mean CV values of the three variables. ) EGG RELATIONSHIPS OF LIZAR DS 15

DISCUSSION The reproductive period of the Israeli lizards considered here is restricted to spring and early su mmer, In order to reproduce, each species of lizard has due to the pronounced climatic diffe rence between evolved so as to devote a certain proportion of the winter and summer. It has often been suggested, that fe male mass (or energy) to produce eggs, and so as to starting the breeding season relatively early in the year divide this biomass into either many or few eggs (Smith enables lizards to produce an additional clutch (thus and Fretwell, 1974). These two aspects represent Goldberg, 1975, 1977). But in our observations lizard different selection pressures, the first primarily affecting species which are geographically (and climatically) the survival of the mother and by this, of the eggs she sympatric nevertheless begin their breeding at diffe rent carries; the second, only the survival of her offspring, specific times in the season. Moreover, the number of since there is no parental care (Pianka, 1986). Both reproductive months (when oviducts contain shelled contribute to increasing the fitness (long-term eggs) is not affected by the seasonal timing of the onset reproduction success) of each individual in the species. of reproduction in itself (Table 2): M. guuulata which 4 PARENfAL INVESTMENT begins to oviposit early in the year had only reproductive months, the same as 0. e/ega11s and Agama The clutch mass of an individual fe male represents a si11aita which begin to reproduce later in spring. Agama compromise between several selection forces. Increased stellio, Agama pa/Iida and L. laevis, which are early­ reproductive effo rt by investing in, and carrying, a larger season reproducers had 7, 6 and 6 months, respectively, clutch mass may lead to increased probability of the whereas the late-season reproducers Aca11thodactylus mother falling victim to predation (Shine, 1980). Vitt and schreiberi and Aca111hodactylus sclllellatus, have an even Congdon (1978) demonstrated that in lizards the specific longer reproductive season of 8 months each. Despite its clutch mass is related to body shape and habitual mode long reproductive season, Lehman (1980) found in the of escape from predators. Nevertheless, it seems that latter only 1-4 clutches per year, with 2-6 eggs per clutch. lizards have attained optimization regarding the No sacrifice at the expense of the first clutch occurs in proportion of clutch mass to mother mass, values which favour of increasing the chance of reproducing a later we represent, respectively, by their correlates, clutch clutch. Constraints and perhaps uncerta111ties volume and body length. Rand (1982) fu rnished concerning the length of the reproductive period lead to comparable data for 13 species of iguanid lizards in a maximization of each clutch; a smaller clutch mass tropical America. We calculate from his data a strong (volume) seems not to be compensated for by the interspecificcorrel ation of clutch volume to body length production of more clutches. By the same token, in a (r = 0.94, P.<: 0.001), with a regression slope of 0.22, not lizard population reproducing biennially (e.g., Anguis significantly different from ours (Fig. 3). Calculation of fragilis - Patterson, 1983), a fe male would not be the diameters of the average specific clutches found by expected to carry a clutch mass double that which Rand (from total clutch masses conceived of as sphere­ accords with her survival. Thus when we deal with the shaped) yields a mean diameter of 25.0 1.7 percra, ± relationships between the number of eggs in a clutch again not significantly different from our result of 23.5 and the volume of each egg, each clutch may be ± 3.2 percra (t-test) (Fig. 4). Thus, clutch diameter regarded independently of others produced by the observes a fairly constant proportion of body length in lizard. these lizard groups. Interestingly, Vitt and Price (1982) too have found that the mean relative clutch mass of NUMBER VERSUS SIZE OF EGGS lizards of the families Agamidae, lguanidae, and Since parental investment (per clutch) in all lizards Lacertidae (also Scincidae) is of a uniform order of considered here is similar (proportional to maternal magnitude, about 25%. Lizard species apparently invest body size), selective forces on reproductive success a certain amount in each clutch, regardless of how many operate along one dimension - increasing either egg clutches are produced during the year. This conclusion volume or egg number, each at the expense of the other. accords with those of Vitt and Congdon (1978) and (This phenomenon is significant in our sample of Rand (1982). On the other hand, Barbault (1975) Acanthodactylus scutellatus, as shown in Table 3.) The suggested that lizards in a fairly stable but predation­ relative importance of each trend for offspring survival heavy environment are selected to increase fe cundity, determines the relationship between egg volume and with an increased clutch volume, even at the expense of number within a clutch. Optimization is reached by a parental survivorship. combination of maximizing both the number of eggs The reproductive investment per clutch seems to be and the probability of each offspring to survive to uniform (by one yardstick) for Mediterranean, desert, maturity, which is believed to significantly depend on subtropical and tropical lizards. A clutch diameter of egg size (Ferguson et al., 1982; Vitt and Price, 1982). about 25 percra represents a widespread value for Dunham and Miles (1985) reported a significant Agamidae, and Lacertidae, presumably as an interspecific correlation of clutch size to maternal body optimal compromise between retammg maternal length but did not consider egg size or clutch volume. survival and increasing reproductive success. In view of In tropical fo rests (and on islands - Fitch, 1985) the near-uniform relative clutch volume, the number of larger young are selected fo r. In other environments a clutches during a year seems to depend on the length of relatively greater nonselective mortality presses more the available reproductive season rather than on the strongly for large clutches (Tinkle, Wilbur and Tilley, investment already made by the lizard at a given time. 1970; Barbault, 1975; Rand, 1982). It is generally The longer the reproductive season, the more clutches contended, though not proven, that tropical forests are are produced. In tropical zones with faint seasonality, stable over time, and that this characteristic accounts for lizards produce numerous clutches during the year the particular apportionment of clutch mass in this (Barbault, 1975). environment. 16 ELIEZER FRANKENBERG AND YEHUDAH L. WERNER

We may summarize the ecological and reproductive Agama sinaita, which lives in extreme arid southern adaptations in the lizard species studied here. Whereas Israel (Hertz and Nevo, 1981) exhibits strong individual both Mediterranean and desert species mostly have territoriality (Arbel, 1981). In such a case of extreme relatively numerous eggs, most species which deviate environmental conditions and strong intraspecific and have large eggs live on sand. The only exception is competition, selection seems to be compromising, both Agama sinaita which has fe w, large eggs and lives on egg number and egg volume increasing with body size. rocks in extreme desert. Initially this seems hard to reconcile with the prevalent theory: Both the CONCLUSIONS Mediterranean and desert habitats in Israel are unstable and unpredictable, as may be seen in Ta ble and as I, The lizards treated here, as a group, basically tend to indicated by the extreme fl uctuations in rainfall and in maximize the number of eggs, presumably because the average temperatures of the warmest month between nonselective or random mortality favour an increased drought and wet years (Atlas of Israel, 1970). Such number of eggs. On the other hand, selection may environments, as suggested by Rand (1982), impose favour large eggs when the conditions for their nonselective mortality of eggs and young, with a development are stable and when a larger offspring has selection pressure towards increasing the number of a better chance to survive (Congdon, Vitt and Hadley eggs per clutch. 1978; Rand, 1982). Desert and Mediterranean Sands, however, seem to have a contrary effect on environments seem to be alike in being unpredictable eggs. The lizards which live on sands bury their eggs in and unstable, selecting for an increase in clutch size, the ground. Due to the special character of the soil, whereas extreme deserts and sandy environments arenicolous lizards are better able to dig, for oviposition, appear to be predictable, though harsh, habitats, down to a level of appropriate moisture. Thus they selecting for large eggs. secure for the eggs a stable environment (Ackerman, in press; Ratterman and Ackerman, 1989) conducive to ACKNOWLEDGEMENTS high hatching success, enabling the evolution of fewer and larger eggs. This project was enabled by the support of The Fund The large eggs of Agama sinaita may also be for Basic Research administered by The Israel Academy explicable by the predictable stability of the conditions of Sciences and Humanities (1980-82). We are also in which they develop. Of all the species investigated obliged to Prof. H. Mendelssohn and Dr. M. Goren for here, this rupicolous desert lizard is the one whose free use of the Te l Aviv University collection; to all occurrence is most strictly restricted to the extreme persons who brought specimens to the Hebrew desert. Conceivably the correct oviposition sites may be University and Te l Aviv University collections, and relatively dry, or rare and hard to locate, or both, but, especially to the late Dr. Hermann Zinner for material once located and employed, the conditions there remain collected in 1965/66 in Lebanon and Syria; to Orit stable. Greenbaum and Merav Frid for most of the measurements and radiography; to Miriam Chertkow EFFECT OF MATERNAL SIZE for graphic and A Niv for photographic assistance; to In three Australian agamids of the genus R.A. Ackerman for an enlightening discussion; and , both clutch size and the number of particularly to Y. Yo m-Tov and several anonymous clutches per year increase with the age of the female reviewers for comments on the manuscript. (Bradshaw, 1981). Certainly, lizard species which are. selected for a relatively large number of eggs in their REFERENCES clutch, would be expected to furtherincrease clutch size with increasing maternal body size; indeed so do six of Ackerman, RA (in press). Physical factors affecting the water the species described here. These include Agama stellio, exchange of buried eggs. In: Physical Influences on for which the same phenomenon has been verified in a Embryonic Development in Birds and Reptiles, ...... Deeming, Greek population (Loumbourdis, 1987). Acanthodactylus D.C. and Ferguson, M.W.J. (Eds.) Cambridge University boskianus is an exception: This species retains the Press. character of laying relatively numerous eggs in its Ackerman, RA, Seagrave, R.C., Dmi'el, R. and Ar, A (1985). 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HERPETOLOGICAL JOURNAL, Vol. 2, pp. 18-23 (1992)

SODIUM CHLORIDE AND POTASSIUM CHLORIDE TOLERANCE OF DIFFERENT STAGES OF THE FROG, MICROHYLA ORNATA

AD. PADHYE AND H.V. GHATE

Post-Graduate Research Centre, Department of Zoology, Modem College, Pune 411 005 India.

(A ccepted 18.6.90)

ABSTRACT

Short term effects of diffe rent concentrations of NaCl and KC! on embryos and tadpoles of the frog Microhyla omata were studied. Both NaCl and KC! caused significant reduction in swelling of the perivitelline space (PVS), an effect very similar to that reported foracidic pH. Tadpoles were observed to be somewhat more resistant to both NaCl as well as KC!, as compared to the embryos. KCl was found to be more toxic than NaCl. A typical teratogenic effect was observed in KC! treated embryos which showed swollen head coelom, whereas NaCl caused incomplete closure of the neural tube.

INTRODUCTION Some work has been done regarding the effects of salinity on breeding and development of a few Amphibian embryos may be exposed to different amphibians (Ely, 1944; Ruibal, 1959; Beebee, 1985). salinities during the period of their embryonic Considerable work has been done on salt tolerance of development. Later the tadpoles also have to face the embryos, tadpoles anp adults of the Indonesian frog varying environmental conditions. The reasons for Rana cancrivora (Gordan et al., 1961; Gordan and variation in salinity are many. Intermittent rainfall often Tucker, 1965; Dunson, 1977). This frog is known to leads to drying of temporary rain-water pools thereby tolerate high salt levels in the ambient medium. increasing the salinity (Munsey, 1972). It is also likely However, no information is available regarding any of that the breeding sites on the coastline may be affected the Indian species of frog. In this study we estimated by tidal inundation. Thus, the salinity of the medium is both the NaCl and the KC! tolerance limits at different an important factor in the developmental ecology of stages of development of the frogMicrohyla omata. amphibians.