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housing conditions on growth of young snapping of egg size and its effects on offspring perfor- turtles. Copeia 1993:475-482. mance. Evolution 44:279-294. PACKARD,G. C., AND M. J. PACKARD. 1988. Physio- , AND R. B. HUEY. 1990. Allometric engineer- logical ecology of reptilian eggs and embryos. In ing: an experimental test of the causes of inter- R. B. Huey and C. Gans (eds.), Biology of the Rep- populational differences in performance. Science tilia, Vol. 16, Ecology B, pp. 523-606. Alan R Liss, 248:1106-1109. New York. , AND P. LICHT. 1991a. Hormonal and physi- ROOSENBURG,W. M. 1991. The diamondback terra- ological control of clutch size, egg size, and egg pin: population dynamics, habitat requirements, shape in the side-blotched lizard (Uta stansbu- and opportunities for conservation. In J. A. Mi- riana): constraints on the evolution of lizard life hursky and A. Chaney (eds.), New Perspectives in histories. J. Exp. Zool. 257:252-264. the Chesapeake System: A Research and Manage- ,AND . 1991b. Proximate constraints on ment Partnership. Proceedings of a Conference, the evolution of egg size, number and total clutch pp. 227-234. Chesapeake Research Consortium mass in lizards. Science 252:1300-1302. Publication No. 137 Solomons, Maryland. , P. DOUGHTY,R. B. HUEY,AND K. ZAMUDIO. 1996. Maternal condition and nest site choice: 1992. Allometric engineering: a causal analysis of an alternative for the maintenance of environ- natural selection on offspring size. Science 258: mental sex determination. Amer. Zool. 36:157-168. 1927-1930. SAS INSTITUTEINC. 1988. SAS/STAT User's Guide SPOTILA,J. R., L. C. ZIMMERMAN,C. A. BINCKLEY,J. S. Release 6.03 Edition. SAS Institute Inc. Cary, North GRUMBLES,D. C. ROSTAL,E. C. BEYER,K. M. PHIL- Carolina. LIPS,AND S. J. KEMP. 1994. Effects of incubation SACHSSE,W. 1984. Long term studies of the repro- conditions on sex determination, hatching suc- duction of Malaclemys terrapincentrata. Acta. Path. cess, and growth of hatchling desert tortoises, Go- Antverp. 78:297-308. pherus agassizii. Herpetol. Monogr. 116-123. SEIGEL,R. A. 1984. Parameters of two populations YNTEMA,C. L. 1976. Effects of incubation tempera- of diamondback terrapins (Malaclemys terrapin)on tures on sexual differentiation in the turtle, Chel- the Atlantic coast of Florida. In R. A. Seigel, L. E. ydra serpentina.J. Morphol. 150:453-462. Hunt, J. L. Knight, L. Malaret, and N. L. Zuschlag, 1981. Characteristics of gonads and oviducts (eds.). Vertebrate Ecology and Systematics-A in hatchlings and young of Chelydraserpentina re- Tribute to Henry S. Fitch, pp. 77-87. Museum of sulting from three incubation temperatures. J. Natural History, University of Kansas, Lawrence. Morphol. 167:297-304. SINERVO,B. 1990. The evolution of maternal invest- ment: an experimental and comparative analysis Accepted: 23 January 1996.

Journalof Herpetology,Vol. 30, No. 2, pp. 204-210, 1996 Copyright 1996 Society for the Study of Amphibians and Reptiles

Dynamics of Range Expansion by Three IntroducedSpecies of Anolis Lizards on

JONATHANB. Losos

Departmentof Biology, CampusBox 1137, WashingtonUniversity, St. Louis,Missouri 63130, USA. E-mail:[email protected]

ABSTRACT.- Three species of Anolis lizards were introduced in this century to Bermuda, an archipelago formerly lacking anoles. A previous study conducted in the early 1960s indicated that A. grahami, the first species introduced, rapidly expanded over almost all of the archipelago. By contrast, the other two species had only attained limited ranges by 1963. I surveyed the extent of range expansion by all three species in 1991 and studied habitat use and behavioral interactions. All three species have been able to expand their ranges into areas occupied by other species, but the rate of range expansion has been relatively slow. The species are ecologically similar, but subtle differences in habitat use exist. Behavioral interactions indicate that A. grahami aggressively responds to conspecifics, displays less aggressively to A. extremus, and flees from the larger A. leachi.

Successful colonization requires not only namics is crucial to understanding how com- reaching a site, but being capable of coping suc- munities become more diverse, but study of nat- cessfully with environmental exigencies and ural colonization is difficult due to its haphaz- interacting with native predators, competitors, ard and unpredictable nature. The introduction and parasites. Knowledge of colonization dy- of non-native species through human agency, RANGE EXPANSION BY INTRODUCED ANOLES 205

St. George's Island /

IrelandIslands St. George's Parish

A. extremus A. absent in grahami 1963 N Smith's Parish

Devonshire Parish

NorthAtlantic Ocean

A. leachi

1 km Southampton Parish FIG.1. Distributionof Anolisspecies in Bermuda.Circles representlocalities at which only A. grahamiwas found; squaresare localities at which both A. grahamiand A. leachiwere found; trianglesare localitiesat which A. grahamiand A. extremuswere found; and the star denotes the locality (MangroveBay) at which all three species were found. Hatched areas represent the distribution of A. extremusand A. leachiin 1963 (Wingate, 1965).The stippled areaindicates the areanot occupied by A. grahamiin 1963.This areais also hatchedbecause A. extremuswas present in this area at that time. disastrous in case after case (e.g., Moyle et al., the geographic spread and habitat use of intro- 1986; Drake et al., 1989), does have one positive duced anole species are affected by the presence aspect: by studying the outcome of such intro- of congeners can provide an informative test of ductions, hypotheses concerning colonization hypotheses concerning Anolis community struc- and community diversification can be tested ture and evolution (Losos et al., 1993). (Moulton and Pimm, 1983; Moulton, 1986). The history of anole introductions to Ber- One well-documented example involves the muda has been well-chronicled by Wingate introduction of three species of the lizard genus (1965). Anolis grahami, native to Jamaica, was Anolis to Bermuda, an archipelago having no introduced to control insect pests (themselves native amphibians and only one native terres- introduced) in 1905 in . By 1963, it trial reptile species, the skink Eumeces longiros- had spread throughout the island with the ex- tris (Wingate, 1965). Interactions among intro- ception of most of the Ireland Islands at the duced species of anoles are particularly inter- northwestern tip of the Bermudian archipelago esting in the context of the extensive literature (Fig. 1). Anolis leachi, native to Antigua and Bar- on community ecology and evolutionary di- buda, appeared in central Bermuda around 1940 versification in this genus (reviewed in Losos, and had spread approximately 2 km to cover 1994). Interspecific competition is an important almost all of by 1963; in addi- determinant of habitat use and geographic dis- tion, a small disjunct colony in Pembroke Parish tribution among Caribbean anole species (e.g., also existed at that time. In 1953, A. extremus, Schoener, 1975; Pacala and Roughgarden, 1982; from Barbados, was discovered in the Royal Salzburg, 1984) and has been implicated as the Dockyards on Ireland Island North and had driving force behind evolutionary specializa- covered that entire island, as well as Ireland tion to particular microhabitats (Williams, 1972; Island South and Boaz island, by 1963. Losos, 1992, 1994). Thus, the extent to which On their native islands, all three species are 206 JONATHAN B. LOSOS

quite similar ecologically, being arboreal with leachi was found in approximately 7 hours]; a vertical distribution from eye-level to the Somerset Railway Trail, [ca. 1?/4 crowns of trees (Rand, 1967; Schoener, 1970; km from grahami only site]) and with A. leachi Schoener and Schoener, 1971; Lazell, 1972). at three sites (Belmont Golf Club, Warwick Par- Anolis leachi is considerably larger than the oth- ish; Riddell's Bay Golf Club, Warwick Parish; er two species, which are approximately the Bermuda Botanical Garden, Paget Parish). Each same size (mean snout-vent length of adult site was visited once beginning after 0900 h and males on Bermuda [Losos, unpubl.]: A. extremus ending by 1545 h (Belmont Golf Club was vis- 73.2 mm; A. grahami, 68.9 mm; A. leachi 102.3 ited twice due to low abundance of grahami). mm). Wingate (1965) noted that A. leachi,which Visits were not made on rainy or overcast days. dominates A. grahami and forces it to shift its The sites were chosen to attempt to cover areas habitat, had spread through areas occupied by with similar vegetation structure. Most of the the latter species. By contrast, A. grahamiand A. sites were mixed landscapes composed of areas extremus,which might be expected to compete containing either thick woods, isolated trees, more intensely because of their similarity in relatively abundant low vegetation or small size (Pacala and Roughgarden, 1985; Rummel buildings. However, the two sites along the and Roughgarden, 1985), were only sympatric railway trail in Sandys Parish were somewhat over a small area at the time of Wingate's study. different in that they were completely wooded, Wingate (1965) speculated that the failure of A. the trees were widely spaced so that one could grahami to colonize most of the Ireland Island walk easily amongst them, and low vegetation may have been due to the presence of A. extre- was relatively scarce. mus. Conversely, the limited range of A. extre- At each site, the following data were recorded mus might be a result of the presence of A. gra- for each adult male observed (Rand, 1967; hami (Wingate, 1965; Roughgarden and Pacala, Schoener and Schoener, 1971): species, height, 1989). diameter of perch (not assigned to animals on I conducted this study to document what the ground), and whether the individual was change in geographic distribution, if any, had in the sun or shade (lizards with 25-75% of their occurred in the 28 yr since Wingate's analysis. body in the sun and the rest in shade were In addition, I investigated whether the species, recorded as in filtered sunlight). To bolster sam- when sympatric, interacted aggressively or dif- ple sizes for the sun/shade analysis, localities fered in habitat use. were grouped and the filtered-sun and full-sun categories were combined. Sample sizes were MATERIALSAND METHODS lower for these analyses than for habitat anal- The current range of Bermudian anoles was yses because no data were recorded when the investigated from 26 June-19 July 1991. I visited sun was not out. Table 1 provides perch height a large number of localities throughout Ber- and diameter data for each species at each lo- muda at which I searched for 5-20 min, usually cality. continuing until 10 lizards had been discov- Behavioral trials were conducted in which ered. Any species not seen was considered ab- one lizard, attached by a dental floss noose sent from a site (in several places where lizards around the waist to a 2 m pole, was moved to were scarce, usually due to weather or lateness within 0.5-1.0 m of a resident male lizard. Be- of hour, searches were discontinued before 10 havior of the resident was observed from a dis- lizards were found). Many sites were visited tance of 2-5 m. Trials were conducted for 15 more than once, and in only one case was a min or until the resident either attacked the species missed in the first visit subsequently intruder or fled. Because for the most part A. discovered (the Mangrove Bay site, where one leachi and A. extremus expanded their ranges A. leachi was discovered at the end of a second into area previously occupied by A. grahami,A. 3+ hour visit). Sites were concentrated near the grahamiwas used as the resident in these trials. borders of the species' ranges to more accurately Some trials were conducted in areas in which delimit the range boundaries. Casual observa- A. grahami occurs alone, whereas others were tions of extremus and leachi at other localities held in areas in which the intruder also occurs. were also recorded. Because no obvious difference in the results were Habitat utilization data were recorded at eight observed, trials were lumped for data presen- sites. Anolisgrahami was present at all eight sites. tation. At three sites, A. grahamioccurred alone (south- Data were In-transformed prior to statistical ern end of Somerset Railway Trail, Sandys Par- analysis. ish [one extremus found in 2/2 hours of search- ing]; St. David's Island; Nonsuch Island), RESULTS whereas it was sympatric with A. extremus at Species Distributions.-Anolis grahami: A. gra- two sites (Mangrove Bay, Sandys Parish [one hami now occupies all of the contiguous Ber- RANGE EXPANSION BY INTRODUCED ANOLES 207 mudian islands and some outlying islands, of- TABLE1. Habitatuse (mean + 1 s.e.) by the three ten at high density (Fig. 1; Nonsuch Island was Anolisspecies on Bermuda.Localities are: 1. In and the only outlying island visited as part of this around the Belmont Golf Course grounds, Warwick study, but Wingate [1965] reported that A. gra- Parish; 2. Nonsuch Island, St. George's Parish; hami has reached others). No sites were visited 3. BermudaBotanical Garden grounds, Paget Parish; at which A. grahami could not be found. 4. Neighborhoods near the BermudaMarine Biolog- Anolis leachi: In the 28 yr since Wingate's cen- ical Station, St. George'sParish; 5. SomersetRailway sus (which was also conducted during summer Trail,north of FortScaur, Sandys Parish;6. Southern months), A. leachi has expanded into the par- end of SomersetRailway trail and FortScaur grounds, ishes of Smith's (7.75 km from the border of its SandysParish; 7. MangroveBay neighborhoods, San- range in 1963), Hamilton (10 km), Southampton dys Parish;8. In and aroundRiddell's Bay Golf Course (7.25 km) and Pembroke (minimally 1.25 km grounds, Warwick Parish. Sample size (N) refers to from the small Pembroke enclave reported by perch height; sample sizes are sometimes lower for Wingate). In addition, one A. leachi was discov- perch diameter. ered at the north end of Sandys Parish, 3 km from the nearest other A. leachi Perch Perch locality. Local- diameter Anolis extremus: Since A. height 1963, extremus has ity Species (m) (cm) N covered the southern third of Somerset Island 1 grahami 1.4 ? 0.2 8.4 + 1.9 22 and has crossed the Somerset Bridge into South- a extension of 1.25 km. 1 leachi 1.9 ? 0.2 13.3 ? 1.8 51 ampton, range Wingate 2 grahami 1.9 + 0.2 6.8 0.6 52 noted that A. extremus was distributed + (1965) 3 grahami 1.9 + 0.2 15.1 + 2.3 41 patchily on Somerset Island, a situation which 3 leachi 1.9 ? 0.3 20.1 + 6.2 12 still exists, as evidenced by the several localities 4 grahami 1.8 + 0.2 8.6 + 1.2 55 on that island at which only A. grahami was 5 grahami 2.2 + 0.3 12.4 + 2.0 55 found. 5 extremus 2.6 ? 0.3 12.2 + 1.7 30 The range extensions reported above for each 6 grahami 2.0 ? 0.2 5.3 + 0.6 41 7 grahami species occurred in areas already occupied by 2.2 + 0.3 10.2 + 1.9 27 7 extremus 1.6 + 0.2 13.7 ? 3.2 27 another Anolis species. With the exception of one site in northern Parish 8 grahami 1.7 + 0.2 8.4 ? 2.5 27 Sandys (discussed 8 leachi 1.9 + 0.2 11.6 ? 1.5 29 below), no localities were visited in which all three species were found. However, in north- ern Southampton Parish, A. leachi and A. extre- mus were found at sites separated by <0.25 km. trials. By contrast, when the intruder was the If I had sampled more intensively in this area, similar-sized A. extremus, the resident usually I might have discovered all three species oc- displayed (nine of 10 trials), but only attacked curring sympatrically. in two trials. When the intruder was A. leachi, Habitat Use.-The species generally are eco- A. grahami fled in all six cases. logically quite similar-they are arboreal liz- DISCUSSION ards usually found around eye level on tree trunks and, less frequently, on branches. Anolis Anolis grahami was introduced to Bermuda in grahamiand A. extremusdiffered in neither perch 1905. In less than 60 yr (by 1963), it had almost height nor perch diameter (Table 2), but A. ex- entirely covered the archipelago. Anolis leachi tremus used the shade more frequently than A. and A. extremushave now been on Bermuda for grahami (92.1% vs. 64.3%; X2= 11.79, 1 d.f., P < almost that long (minimally 56 and 43 yr, re- 0.005). Anolis leachi and A. grahami also did not spectively [Wingate, 1965]), but their expansion differ in perch height (Table 2) or use of shade has been considerably less rapid: A. leachi now (71.8% vs. 69.9%;x2 = 0.06, 1 d.f., P > 0.80), but covers approximately half of the archipelago they did differ in perch diameter, with A. leachi and A. extremus is still restricted to a relatively occurring on larger diameter surfaces (Table 2). small area in northwestern Bermuda. Compar- In the perch diameter analysis for these two ison of the rate of spread of the three species is species, there was also a significant locality ef- complicated by human agency. Wingate (1965, fect, which was not apparent in any of the other pp. 213) noted that "because Anolis [grahami]was analyses. In addition, use of shade by A. grahami a novelty in Bermuda, the dispersion was aided did not differ between sites at which it occurred by various people who caught lizards in the alone, co-occurred with A. extremus, or co-oc- central parishes for release in gardens at either curred with A. leachi (2 = 0.89, 2 d.f., P > 0.60). end of the island." Interspecific Behavioral Interactions.-The be- Similarly, A. leachi may have been transport- havior of resident A. grahami differed depend- ed around the island either intentionally, as ing on the identity of the intruder. Resident Wingate described for A. grahami, or uninten- Anolis grahami attacked conspecifics in 7 of 11 tionally by thriving Bermudian horticultural 208 JONATHAN B. LOSOS

TABLE2. Two-way analyses of variancefor differencesin habitatuse at sympatricspecies localities. Un- published multivariateanalyses of varianceprovided similar results.

Sumof squares d.f. Meansquare F-Ratio P a) A. grahami-A.extremus i) Perch Height Species 0.014 1 0.014 0.020 0.888 Locality 1.460 1 1.460 2.156 0.145 Species x Locality 2.275 1 2.275 3.359 0.069 Error 77.218 114 0.677 ii) Perch Diameter Species 0.770 1 0.770 1.034 0.312 Locality 0.906 1 0.906 1.216 0.273 Species x Locality 0.407 1 0.407 0.547 0.461 Error 78.199 105 0.745 b) A. grahami-A.leachi i) Perch Height Species 1.348 1 1.348 2.710 0.102 Locality 1.334 2 0.667 1.341 0.264 Species x Locality 0.710 2 0.355 0.714 0.491 Error 87.571 176 0.498 ii) Perch Diameter Species 4.433 1 4.433 4.922 0.028 Locality 6.695 2 3.347 3.717 0.026 Species x Locality 1.657 2 0.829 0.920 0.401 Error 139.585 155 0.901

businesses, as several Bermudians suggested to competitors, the two subsequently introduced me. In support of the former possibility, Mr. R. species were forced to expand into areas already Winchell of the Bermuda Aquarium informed occupied by a potentially competing species. me (pers. comm.) that A. leachi had been intro- Indeed, compelling evidence exists that inter- duced intentionally onto the aquarium grounds specific competition is an important factor in northern Smith's Parish. With regard to the structuring anole communities in general (Lo- possibility that nurseries were transporting liz- sos, 1994). Of course, other factors may have ards along with the plants they sell, one nursery contributed to the interspecific differences in operator I spoke with said she had never seen rate of range expansion, including the loss of lizards transported on nursery deliveries be- tree cover in the 1940s, after A. grahami was cause the lizards always abandoned the plants already widely distributed (Wingate, 1965), or as they were loaded onto vehicles; still, eggs differences in predation pressure, human trans- could easily be translocated in this manner. Cer- port (discussed above), or susceptibility to cold tainly, the isolated populations of A. leachi in weather (see Wingate, 1965). Pembroke Parish originally reported by Win- Second, colonizing species can become estab- gate (1965; but no longer isolated from the main lished and expand their range in the presence A. leachi population; Fig. 1) and in Sandy's Par- of ecologically similar resident species. This ish (this study) suggest that humans may have finding is important because theories of com- played a role in their dispersal. petition-induced coevolutionary change (e.g., Regardless of the mechanism by which these character displacement) require as their first species have expanded their range, these find- stage that similar species exist in sympatry. Some ings suggest two important conclusions con- theoretical treatments predict that two ecolog- cerning anole community structure. First, as ically similar species cannot coexist long enough Wingate (1965) noted, the presence of A. gra- for evolutionary change because one species is hami may have inhibited the spread of the two likely to become extinct (reviewed in Taper and subsequently introduced species. This result Case, 1992). However, the case of A. extremus would not be surprising given the similarity of and A. grahami indicates that species similar in the three species in habitat use (Wingate, 1965; both ecology and body size can not only coexist, Schoener, 1970; this study) and diet (Simmonds, but also can expand their ranges into areas oc- 1958; Wingate, 1965). Thus, whereas A. grahami cupied by the other species (A. grahamiinto the was able to expand into areas unoccupied by Ireland Islands, A. extremus into Sandys and RANGE EXPANSION BY INTRODUCED ANOLES 209

Southampton Parish). Knowledgeable Bermu- utilize distinctive microhabitats; (3) subsequent dian naturalists had informed me where to look evolutionary adaptation to these niches leads to find these species sympatrically; thus, these to the evolution of specialized morphologies records probably represent real range expan- and physiologies; and (4) repeated instances of sions rather than aberrant or seasonal occur- this specialization produce communities con- rences. taining a suite of specialist species (Williams, Although ecologically similar, the species are 1972, 1983; Losos, 1992, 1994). Anole introduc- not identical; ecological differences between the tions in Bermuda thus re-create the conditions species may be sufficient for coexistence. Anolis of the first stage of this hypothesis when eco- leachi is considerably larger than the other two logically similar species come into contact. The species and thus can take prey too large to be results reported here indicate that such species consumed by the other species (Wingate, 1965; can coexist and even expand their range. In- a relationship between body size and prey size vestigation of the next step in the hypothesis- is common in anoles [e.g., Schoener and Gor- adaptation to particular microhabitats-would man, 1968; Roughgarden, 1974]). In sympatry, provide a valuable test of the anole adaptive A. leachi is behaviorally dominant to A. grahami radiation hypothesis. and and forces it to use (Wingate [1965] above) to work on more that are too small for Acknowledgments.-For permission peripheral perches their I thank Mrs. Mr. A. leachi. differences property, Fay Watlington, Although vegetational pre- David Nonsuch Is- cluded of whether A. shifts Wingate (Superintendent, investigation grahami The Bermuda Marine its habitat use in the of A. Schoe- land), Biological Station, presence leachi, Bermuda Botanical Garden, Belmont Golf ner's which corrected for dif- Club, (1975) analysis, and Riddell's Golf Club. For assistance, ad- ferences in habitat sites, Bay availability among vice, information, and comments on found such a shift. the coexis- previous Consequently, versions of this I thank D. tence of these two result both from manuscript, Wingate, species may S. DeSilva, T. Schoener, R. L. Wil- differences in utilization and in the Henderson, prey ability son, R. Winchell, and an reviewer. of the subordinate A. to anonymous behaviorally grahami Field work was assisted C. J. Lo- use habitats unavailable to A. leachi. ably by Losos, D. and S. C. Baxter. Permission Anolis extremus and A. are sos, Silverman, grahami similarly- to conduct this research was sized and utilize similar kindly granted by prey (Wingate, 1965). N. of Fisher- differ in their use of thermal microhabitat: Burnie, Department Agriculture, They and Bermuda. This research was A. extremus cooler areas and is more of- ies, Parks, prefers funded a from the National ten found in the shade relative to the more by grant Geograph- ic Society and by the Center for Population Bi- heliophilic A. grahami (Wingate, 1965; Schoe- ology, University of California, Davis. ner, 1970; this study). These preferences are so extreme that the occupation of a particular perch LITERATURECrrED will from one to the other dur- change species A., H. A. F. DICASTRI, R. H. the course of the as the inso- DRAKE,J. MOONEY, GROVES, ing day perch's F. KRUGER,M. REJMANEK,AND M. WILLIAMSON. lation from sun-to-shade or vice-versa J. changes 1989. Biological Invasions: A Global Perspective. (Schoener, 1970; Losos, unpubl.). This study Scope 37. John Wiley & Sons: Chichester, U.K. failed to find a difference between the two spe- LAZELL,J. D., JR. 1972. The anoles (Sauria: Iguanidae) cies in perch height or diameter, but Schoener's of the LesserAntilles. Bull. Mus. Comp. Zool. 143: previous study (1970) found slight differences 1-115. B. 1992. The in perch diameter and height (A. grahami on Losos, J. evolution of convergentstruc- ture in CaribbeanAnolis communities. Biol. higher and thinner perches). Consequently, I Syst. conclude that A. and A. extremus are 41:403-420. grahami . 1994. studies of similar to Integrative evolutionary enough ecologically compete for re- Anolis lizards as a model Ann. and thus slow their ecology: system. sources, range expansions, Rev. Ecol. Syst. 25:467-493. but are not so similar as to preclude coexistence. , J. C. MARKS,AND T. W. SCHOENER.1993. Hab- A review of 23 anole introductions in the Ca- itat use and ecological interactions of an intro- ribbean indicates that this is a common outcome duced and a native species of Anolis lizard on Grand of anole introductions (Losos et al., 1993). Cayman, with a review of the outcomes of anole Conclusions.-The study of introduced species introductions. Oecologia (Berlin) 95:525-532. M. P. 1986. The extent of in can provide insight into the assembly of multi- MOULTON, competition communities. Anolis has in- shaping an introduced avifauna. In J. Diamond species experienced and T. Case 80- radiations on each of (eds.), Community Ecology, pp. dependent evolutionary 97. Harper and Row, Cambridge. the islands in the Greater Antilles (Williams, , AND S. L. PIMM. 1983. The introduced Ha- 1972). One model of this radiation posits that: waiian avifauna: biogeographic evidence for com- (1) ecologically similar species come into sym- petition. Amer. Natur. 121:669-690. patry; (2) competitive pressures force them to MOYLE,P. B., H. W. LI, ANDB. A. BARTON.1986. The 210 JONATHAN B. LOSOS

Frankenstein effect: impact of introduced fishes 1975. Presence and absence of habitat shift on native fishes in North America. In R. H. Stroud in some widespread lizard species. Ecol. Monogr. (ed.), Fish Culture in Fisheries Management, pp. 45:233-258. 415-426. Am. Fisheries Soc., Bethesda. , AND G. C. GORMAN.1968. Some niche dif- PACALA,S. W., AND J. ROUGHGARDEN. 1985. Popu- ferences in three Lesser-Antillean lizards of the lation experiments with the Anolis lizards of St. genus Anolis. Ecology 49:819-830. Maarten and St. Eustatius. Ecology 66:129-141. SCHOENER,T. W., ANDA. SCHOENER.1971. Structural RAND, A. S. 1967. The ecological distribution of an- habitats of West Indian Anolis lizards. I. Jamaican oline lizards around Kingston, Jamaica. Breviora lowlands. Breviora 368:1-53. 282:1-18. SIMMONDS, F. J. 1958. The effect of lizards on the ROUGHGARDEN,J. 1974. Niche width: biogeographic biological control of scale insects in Bermuda. Bull. patterns among Anolis lizard populations. Amer. Entomol. Res. 49:601-612. Natur. 108:429-442. TAPER,M. L., AND T. J. CASE.1992. Coevolution among , AND S. PACALA. 1989. Taxon cycle among competitors. Oxford Surv. Evol. Biol. 8:63-109. Anolis lizard populations: review of the evidence. WILLIAMS,E. E. 1972. The origin of faunas. Evolution In D. Otte and J. Endler (eds.), Speciation and Its of lizard congeners in a complex island fauna: a Consequences, pp. 403-432. Sinauer, Sunderland, trial analysis. Evol. Biol. 6:47-89. Massachusetts. . 1983. Ecomorphs, faunas, island size, and RUMMEL,J. D., ANDJ. D. ROUGHGARDEN.1985. Effects diverse end points in island radiations of Anolis. of reduced perch-height separation on competi- In R. B. Huey, E. R. Pianka, and T. W. Schoener tion between two Anolis lizards. Ecology 66:430- (eds.), Lizard Ecology: Studies of a Model Organ- 444. ism, pp. 326-370. Harvard University Press, Cam- SALZBURG,M. A. 1984. Anolis sagrei and Anolis cris- bridge, Massachusetts. tatellus in southern Florida: a case study in inter- WINGATE, D. B. 1965. Terrestrial herpetofauna of specific competition. Ecology 65:14-19. Bermuda. Herpetologica 21:199-219. SCHOENER,T. W. 1970. Nonsynchronous spatial overlap of lizards in patchy habitats. Ecology 51: Accepted: 23 January 1996. 408-418.