Great Basin Naturalist

Volume 57 Number 4 Article 10

10-31-1997

Reproduction in the western coral snake, Micruroides euryxanthus (Elapidae), from Arizona and Sonora, México

Stephen R. Goldberg Whittier College, Whittier, California

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Recommended Citation Goldberg, Stephen R. (1997) "Reproduction in the western coral snake, Micruroides euryxanthus (Elapidae), from Arizona and Sonora, México," Great Basin Naturalist: Vol. 57 : No. 4 , Article 10. Available at: https://scholarsarchive.byu.edu/gbn/vol57/iss4/10

This Note is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Great Basin Naturalist 57(4), © 1997, pp. 363-365

REPRODUCTION IN THE WESTERN CORAL SNAKE, MICRUROIDES EURYXANTHUS (ELAPIDAE), FROM ARIZONA AND SONORA, MEXICO

Stephen R. Goldberg!

Key words: reproduction, Micruroides euryxanthus, western coral snake, Arizona, Mexico.

The western coral snake, Micruroides eury­ cut into sections at 5 J..Lm. Slides were stained xanthWJ (Kennicott, 1860), ranges from central with Harris' hematoxylin followed by eosin Arizona and southwestern New Mexico to counterstain. Testes slides were examined to southern Sinaloa, Mexico, and occurs from sea determine the stage of the male cycle; epi­ level to 1770 m (Stebbins 1985). Information didymides and vasa deferentia were examined on the biology ofthis species is in Roze (1974). for sperm. Slides of kidney sexual segments There are only anecdotal accounts of repro­ were examined for secretory activity. Ovary duction in M. euryxanthWJ (Funk 1964, Behler slides were examined for the presence of yolk and King 1979, Stehbins 1985, Ernst 1992, deposition. Williamson et aI. 1994, Rossi and Rossi 1995, Data on the male Micruroides euryxanthWJ Degenhardt et aI. 1996). According to Lowe testicular cycle are presented in Table 1. Tes­ et aI. (1986), the M. euryxanthWJ reproductive ticular histology was similar to that reported cycle is tied to summer rains; egg laying occurs by Goldberg and Parker (1975) for the colu­ in July-August with hatchlings appearing in brid snakes Masticophis taeniatWJ and Pituophis summer. Shaw (1971) assnmed breeding melanoleUCW!. In the regressed testes seminif­ occurred in the spring, with egg deposition in erous tubules contained spermatogonia and late spring or early summer. Roze (1996) re­ Sertoli cells. In recrudescence there was re­ ported that in Sonora, Mexico, oviductal eggs newal of spermatogenic cells characterized by were found in M. euryxanthWJ in the 2nd half spermatogonial divisions; primary and sec­ of May and the end of July; egg laying ondary spermatocytes and spermatids may have stretched from the end of July to September. been present. In spermiogenesis metamor­ The purpose of this report is to provide infor­ phosing spermatids and mature sperm were mation on reproduction in M. euryxanthus. present. Males undergoing spermiogenesis I report on data from 56 Micruroides eury­ were found in all months examined (April- xanthWJ (35 males, mean snout-vent length . November; Table 1). Epididymides and vasa [SVL] = 382 mm + 41.9 s, range 320-493 mm; deferentia of spermiogenic males contained 21 females, mean SVL = 371 mm ± 49.7 s, sperm. The smallest spermiogenic male mea­ range 315-497 mm) from Arizona and Sonora, sured 320 mm SVL. Only 2 males with re­ Mexico, in the herpetology collections of the gressed testes were found, 1 each in June (493 University of Arizona (UAZ), Tucson, and the mm SVL) and August (330 mm SVL). No males Natural History Museum ofLos Angeles County with recrudescent testes were noted. The sex­ (LACM), Los Angeles (Appendix). Counts were ual segment of the kidney was enlarged and made of oviductal eggs or enlarged follicles contained densely staining secretory granules (>3 mm diameter). The left testis, epididymis, in spermiogenic males. Mating coincides with and vas deferens and part of the kidney were hypertrophy ofthe kidney sexual segment (Saint removed from males; the left ovary was re­ Girons 1982). moved from females for histological examioa­ The smallest reproductively active female tion. Tissues were embedded in paraffin and (enlarging eggs) measured 356 mm SVL. To

lDepartment ofBiology, Whittier College, Whittier, CA 00608,

363 364 CHEAT BASIN NATURALIST [Volume 57

TABLE 1. Monthly distribution of conditions in seasonal the time frame for egg laying snggested by testicular cycle of Micruroides euryxanthus. Values shown Lowe et a1. (1986) for Arizona (July-Augnst) arc the numbers of males with testes exhibiting each of the 2 conditions; none were in recrudescence. and Roze (1996) for Sonora, Mexico (end ofJuly to September). Qninn (1979) reported that a \1onth N Regressed Spermiogenesis few females of the Texas coral snake, l\licrurus April I 0 I Ittlvius tener, laid eggs in May but most were May 3 0 3 deposited in June. September newborn M. (3U1ij­ June 3 I 2 xanthus measured 190-200 mm (total length) July 2 0 2 August 11 1 10 and weighed 1.5 g (Lowe et al. 1986). September 9 0 9 Spermiogenesis occurred in all months in October 5 0 5 which testes of Micruroides euryxanthus were November 1 0 I examined (April-November). This may suggest that spermiogenesis is continuous and that males are capable of breeding throughont the avoid the possibility ofusing immature females, year; this would support Rossi and Rossi (1995), I included only Micruroides euryxanthus of who stated that mating may occur in the fall as this size or larger in my analysis of the female well as in spring. Qninn (1979) similarly re­ reproductive cycle. One female from 31 May ported an extended period of spermiogenesis (356 mm SVL) contained 3 enlarging eggs (4-5 (all months except May, June, and July) in Micrurusfulvius tener. The reproductive cycle mm diameter). One female (440 mm SVL) horn of -"'1. euryxanthus appears to fit into Saint 23 June contained 6 oviductal eggs (6-7 mm Cirons' ( 1982) category "spermatogenesis of diameter) which may represent the largest mixed type A," in which there is mating in fall published clutch size for this species. Two and spring with a long period ofspermiogenesis. females, 1 from 30 May (497 mm SVL) aud 1 from 13 July (357 mm SVL), contained folli­ ACKNOWLEDGMENTS cles in early vitellogenesis (yolk granules pre­ sent). The other females examined were not 1 tbank Charles H. Lowe (Department of reproductively active. This included 1 female Ecology and Evolutionary Biology, University from May (374 mm SVL), 1 from June (370 of Arizona) and Robert L. Bezy (Natural His­ mm SVL), 1 from July (386 mm SVL), 2 from tory Museum of Los Angeles County) for per­ September (SVLs 381 mm, 393 mm), 2 from mission to examine l\licruroides euryxanthus, October (SVLs 363 mm, 493 mm). Funk (1964) and Jeffrey Feng (Whittier College) for techni­ reported 2 oviductal eggs in a single M. eury­ cal assistance. Estella J. Hernandez assisted xanthus from Pima County, Arizona, collected with histology. 20 July. Stebbins (19&5), Williamson et aI. (1994), Rossi and Rossi (1995), and Degenhardt et al. LTTEHATURE CITED (1996) reported that clutches contained 2-3 eggs. My female sample size is too small to BEHLER, lL., AND F.w. KING. 1979. The Audubon Society speculate on what proportion of the female field guide to North American reptiles and amphib­ ians. Alfred A. Knopf, NY. 743 pp. population produces eggs each year. However, DEGE::-U-f,\RDT, we., C.\'\Z PAI."I'l'ER, AND A.H. PRICE. 1996. my finding of 1 May and 1 June females with Amphibians and reptiles of New Mexico. University inactive ovaries may suggest that not all females of New Mexico Press, Albuquerque. 431 PP. reproduce annually. The female from Jnly with ElINST, C.H. 1992. Venomous reptiles of North America. Smithsonian Institution Press, Washington DC. 236 inactive ovaries (no yolk deposition) may have pp. already deposited eggs. It will be necessary to FUNK, R.S. 1964. On the reproduction ofMicruruides eury­ examine more female 11,11. euryxanthus before a xanthus (Kennicott). Copeia 1964:219. conclusive statement can be made. Quinn (1979) COLDBEHG, S.R. 1995a. Reproduction in the western patch­ found oviductal eggs in only 2/74 (3%) female nose snake, Salvadora hexalepis, and the mountain patchnose snake, Salvadora grahamiae (Colubridae), Micrurus fulvius tener from Texas. Only a por­ from Arizona. Southwestern Naturalist 40:119-120. tion of the female population breeds in other . 1995b. Reproductiun in the lyre snake, Trirnor­ snakes from the North American desert (Gold­ --p'hodon bisctdatus (Coluhridae), from Arizona. South­ berg 1995a, 1995b, 1995c, 1996, 1997). western Naturalist 40:334-335. . lOOSe. Reproduction in the handed sand snake. My limited data on the Micruroides eury­ -~Chilomeniscus cinctus (Colubridac), from Arizona. xanthus ovarian cycle appear compatible with Great Basin Naturalist 55:372-373. 1997] NOTES 365

__;;,' 1996. Reproduction in the saddled leafnose snake. ico. Pages 157-172 in. W Bucherl and f.E. Buckley, Phyllorhynchus browni and the spotted leafnose editors, Venomous animals and their venoms. Volume snake, f'hyllorllyndw,s d€CUfiatw, from Arizona. Jour­ II. Venomous vertebrates. Academic Press, Y. nal ofHerpetology 30:28~282. STEBBINS, R.C. 1985. A field guide to western reptiles and . 1997. Reproduction in the western shovelnose amphibians. Houghton-Mimin, Boston. 336 pp. --"-lake, Chionacrn occipitalis (Colubridae). from Cali­ WrLLIAMsoN, M.A., P.w. HYDER, AND J.S. ApPLECARTH. fornia. Great Basin Naturalist 57:85-87. 1994. Snakes, lizards, turtles, frogs, toads and salaman­ COLDBERG, S.R, AND \Y.S. PARKEfl. 1975. Seasonal testicu­ ders of New Mell:ico. Sunstone Press, Santa Fe, NM. lar histology of the colubrid snakes, Masticaphi$ tae· 176pp. ntatus and Pituophis m.elanoleucus. Herpetologica 31; 317-322. Received 15 February 1997 loWE, C.H., C,R. SCHWALBE, ....ND T.B. JOHNSON. 1986. Accepted 2 Aptil1997 The venomous reptiles of Arizona. Arizona Game and Fish Department, Phoenix. 115 pp. Qun.-ri, H.R. 1979. Reproduction and growth of the Texas coral snake (Micrurus fult,;iw tenere). Copeta 1979: 453-463. ROSSI, j.Y., AND R. ROSSI. 1995. Snakes orthe United States ApPENDIX and Canada Keeping them healthy in captivity. Vol­ ume 2. Western area KriegeT Publishing Company, Specimens e;\:amined from herpetology collections at M.Jabar, FL. 325 pp. the Natural History Museum of Los Angeles Coun!}' ROZE, J.A. 1974. Micruroidu Schmidt Western coral snake. (LACM) and the University of Arizona (UAZ). Sonora, Catalogue of American Amphibians and Reptiles Mexico, LACM 16056, 104325. UAZ 9358, 27079, 35214, 163.1-163.4. 44875-76, 45202-203, 45904. Arizona, Cochise: UAZ --c;' 1996. Coral snakes of the Americas: biology. iden­ 1443,5, 14616, 39679, 39681, 45843, 46378. 46834, 50046. tification, and venoms. Krieger Publishing Company, Gila: 43287. Pima: UAZ 9360, 14429-3l, 14433, 14436, Malabar, FL. 328 pp. 14438-39, 14441-42, 1444.5-46. 14451, 14618-19,27075, SAIYr GIlIONS, H. 1982. Reproductive cycles of male snakes 29658, 34459, 35829, 36557, 37831. 40874, 42608, 45011, and their relationships with climate and female repro­ 46420, 47344, 47432, 47484. 48342, 48784. Pinal, UAZ ductive cycles. Herpetologica 38$-16. 14432, 14434, 14444. Santa Cruz: VAZ 39677. Yavapai: SHAW, c.E. 1971. The coral snakes, genera Micrurus and UAZ 14443. 39669, 4,5748. Micruroides, of the United States and northern Mex-