EGG LAYING IN SMOOTH NEWTS 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 newt (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 Animal 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 Reptiles. 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 LIZARDS: INTRA- AND INTERSPECIFIC RELATIONS IN NEAR-EASTERN AGAMIDAE AND LACERTIDAE 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 habitat: fossorial (burrowing) Fig. I. A typical small deser1 lacer1id lizard, Mesalina 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 Desert 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 snakes 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 taxonomy 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).