Society for the Study of Amphibians and Reptiles Biting in the Salamander Siren intermedia intermedia: Courtship Component or Agonistic Behavior? Author(s): John E. Fauth and William J. Resetarits, Jr. Source: Journal of Herpetology, Vol. 33, No. 3 (Sep., 1999), pp. 493-496 Published by: Society for the Study of Amphibians and Reptiles Stable URL: http://www.jstor.org/stable/1565651 . Accessed: 17/03/2014 14:32 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Society for the Study of Amphibians and Reptiles is collaborating with JSTOR to digitize, preserve and extend access to Journal of Herpetology. http://www.jstor.org This content downloaded from 137.187.180.221 on Mon, 17 Mar 2014 14:32:02 PM All use subject to JSTOR Terms and Conditions SHORTER COMMUNICATIONS 493 Journalof Herpetology,Vol. 33, No. 3, pp. 493-496, 1999 Copyright1999 Society for the Study of Amphibiansand Reptiles 25- I i I Biting in the Salamander 20- Siren intermedia intermedia: Courtship .......... A. .. .............. I~~~~~?r............... ? Component or Agonistic Behavior? ,j1 I JOHN E. FAUTH,1 AND WILLIAM J. RESETARITS,JR.,2'3 I 'Department of Biology, College of Charleston, 66 George Street, Charleston, South Carolina 29424-0001, USA, E- 15- mail: [email protected] 2Centerfor Aquatic Ecology, Il- 10- linois Natural History Survey, 607 East Peabody Drive, Champaign,Illinois 61820-6242, USA, E-mail: [email protected]. 5- I In salamanders, biting serves three potential pur- Absent Present poses: subduing prey (e.g., Reilly and Lauder, 1990), repelling competitors and predators (e.g., Jaeger, 1981; Brodie et al., 1989), and stimulating the opposite sex Bite scars? In Siren during courtship (Arnold, 1977). intermedia, FIG. 1. Quantile box plots of the snout-vent length was first Gehlbach nonpredatory biting reported by (cm) of 105 field-caught Siren intermedia intermedia and Walker (1970), who observed it while recording from Scotland and Richmond Counties, North Caro- underwater vocalizations. Bitten individuals often fled lina, USA, as a function of the presence or absence of while that could be submissive or emitting yelps bite scars. These epidermal injuries were inflicted by alarm calls, that was an suggesting biting agonistic the keratinized beak and/or vomerine dental array of behavior. Later, demonstrated with con- Godley (1983) conspecifics. Lower and upper ends of the quantile and illustrations that distinctive vincing photographs boxes are 25th and 75th percentiles, respectively; the epidermal marks on six female sirens matched the cor- solid horizontal bar within each box is the median. nified beaks and vomerine teeth of No conspecifics. The upper and lower hash marks denote the 10th and bite scars were observed on females outside the breed- 90th percentiles, respectively. The dotted horizontal season, nor on males in the 489 ing any specimens line indicates the overall sample mean. Solid squares him to that is a necropsied, leading suggest "biting are individual data points. vigorous and important component of courtship in this species." Additional indirect evidence supporting this view was the sexual dimorphism characteristic of in the mean SVL of individuals with and without bite some of S. intermediaand S. lacertina populations (Dav- scars, and a G-test of independence (Sokal and Rohlf, is and Gehlbach and Ken- Knapp, 1953; Martof, 1973; 1995) to determine if bite scars were equally prevalent 1978; Hanlin and the nedy, Mount, 1978), particularly during and after the November-March breeding sea- masseter muscles of which enlarged males, could be son (Collette and Gehlbach, 1961; Petranka, 1998; J. E. in social or behavior. Howev- important reproductive Fauth and W J. Resetarits, Jr., pers. obs.) in this field neither this evidence nor the small er, morphological sample. number of females with bite scars of the sam- (<1.5% Scarred individuals were significantly larger than demonstrate that is related or ple) conclusively biting those without bite marks, even after adjusting for une- restricted to we data from courtship. Here, present qual variances (Welch F, 5.3 = 6.04, P < 0.018; Fig. 1). field sampling and a field experiment that bear on this No sirens smaller than 128 mm SVL had bite scars. question. Frequency of bite scars varied with season (G2 = We 105 S. intermedia intermedia from two sampled 9.561, P < 0.002; Table 1). Individuals with bite scars Carolina in Scotland and Richmond bays Counties, were more prevalent than expected during the breed- North USA from 1987 Nov- Carolina, May through ing season (cell x2 = 4.20), but sirens also had fresh ember 1989. The sites are described elsewhere (Harris bite scars during the nonbreeding season. et Resetarits and Sirens were al., 1988; Fauth, 1998). We also observed bite scars in an experiment inves- on 14 dates and minnow captured using dipnets tigating competition between juvenile S. intermediain- then to the where traps, transported laboratory, they termedia and adult broken-striped newts, Notophthal- were anesthetized in 2% chloretone checked solution, mus viridescens dorsalis (Resetarits and Fauth, unpubl. for bite and measured scars, (snout-vent length [SVL] data). The subset of experimental treatments relevant and total before returned to their length [TL]) being to the issue of biting by sirens involved raising two natal We were unable to sex individuals because pond. juvenile S. i. intermediaeither alone, or with three male this lacked external population sexually dimorphic N. v. dorsalis. Densities of both S. i. intermedia (1.12 characters. We used a Welch ANOVA in version JMP yearlings/m2) and N. v dorsalis (1.6 adults/m2) were 3.2.2 to test for differences (SAS Institute, Inc., 1998) within the range of densities observed in natural po- pulations (Gehlbach and Kennedy, 1978; Sugg et al., 1988; Harris et al., 1988). We used only male N. v. dor- 3Present Address: Department of Biological Sci- salis to prevent newts from reproducing. Sirens could ences, Old Dominion University, Norfolk, Virginia not be sexed based on external characters, so the dis- 23529-0266, USA. E-mail: [email protected] tribution of males and females among ponds resulted This content downloaded from 137.187.180.221 on Mon, 17 Mar 2014 14:32:02 PM All use subject to JSTOR Terms and Conditions 494 SHORTER COMMUNICATIONS TABLE 1. Frequency of bite scars in 105 Siren inter- Inc., 1998) to determine whether scarred individuals were distributed of sex and media intermediasampled from two Carolina bays in independently experimen- tal treatment. Scotland and Richmond Counties, North Carolina, All 16 of the S. i. intermediasurvived USA, as a function of season. Entries are total number experimental until the end of the and dissection re- with without dur- experiment, of individuals observed and scars vealed that seven were male and nine were female. the or ing breeding (November-March) nonbreeding Most of the females fully matured during the experi- values. The fre- (April-October) season, plus expected ment; eight had at least some mature follicles, while quency of bite scars varied significantly with season one had only vitellogenic follicles. Seven of the 16 in- (G2 = 9.561, P < 0.002). dividuals (44%) bore distinctive scars inflicted by con- specifics on the trunk and tail. Bite scars were inde- # # pendent of the presence and absence of N. v dorsalis individuals individuals (G2 = 2.075, P > 0.10). The smallest individual with Season Condition observed expected bite scars in the experiment was 128 mm SVL, the same lower size limit as in the natural breeding no scars 30 36.4 population. More male of than female of sirens breeding scars 16 9.6 (4 7:57%) (3 9:33%) had bite but the difference was not nonbreeding no scars 53 46.6 scars, statistically = P > ex- nonbreeding scars 6 12.4 significant (G2 0.907, 0.34). However, every perimental pond that contained at least one male siren yielded at least one individual with scars, while the three female sirens had no in- from field-collected individuals ponds containing only randomly assigning dividuals with scars. The exact of this out- to the units. probability experimental come is = 0.053. the of males We conducted the in an of twelve (3/8)3 Thus, presence experiment array have been to elicit and six of artificial m 0.5 m at the may necessary biting, ponds (1.5 diameter, deep) the seven sirens that inflicted the bites were Duke Field Station, Durham, North Carolina (86%) Zoology males. from 1986. Our method of reconstruct- April-October Sirens in natural bite marks communities followed that of Morin ponds displayed ing pond closely the and data from our tanks were filled with 1000 L of water, throughout year, experiment (1983). Briefly, demonstrated that both male and female sirens re- and 1.0 kg of dried pond litter was added to provide ceive bites from outside the breeding sea- spatial complexity and nutrients. Two 1 L inoculations conspecifics son, that is not associated with of a pond water suspension on 28 and 29 April added indicating biting solely In encounters (A. J. phytoplankton, periphyton and microorganisms. Fifty courtship. videotaped laboratory of rabbit food were added to a burst Pappas and J. E. Fauth, unpubl. data), we observed grams provide more than 30 incidents without indication of nutrients, and ten stems of an biting any aquatic macrophyte of behavior. The bitten individual (Myriophyllumsp.) provided additional structure and courtship usually fled, often as realism.