Red-sided garter snake

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Red-sided garter snake
Parietalis.JPG
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Colubridae
Genus: Thamnophis
Species:
Subspecies:
T. s. parietalis
Trinomial name
Thamnophis sirtalis parietalis
(Say, 1823)
Synonyms

Coluber parietalisSay, 1823

The red-sided garter snake (Thamnophis sirtalis parietalis) is a subspecies of the common garter snake, in the subfamily Natricinae of the family Colubridae. [1] This slender subspecies of natricine snake is indigenous to North America and is one of the recognized subspecies of Thamnophis sirtalis. [2] [3] This subspecies is widely spread across northern United States and southern Canada. [4] [5]

Contents

Appearance

The red-sided garter snakes have an upper row of well-defined red spots, and lower row with patches of red color that smear on the dark area on either side of their back. [6] These snakes have multiple yellow stripes present on their body. Thamnophis sirtalis parietalis is sexually dimorphic, where females are usually larger than males. [4] The females can range from 18 to 24 inches in length, whereas males can grow up to 12 to 18 inches. [4] The snakes of this subspecies are mainly non-venomous. [7]

Phenology and habitat use

Winter temperatures near their habitat are very harsh and sometimes even drop below zero. [8] During low temperatures in fall and winter, tens of thousands of male and female red-sided garter snakes hibernate together, in a shared underground communal den, for about eight months each year to protect themselves from cold weather and predators. [9] [10] [11] When the temperature rises around 25 °C, it leads to the emergence of these snakes from their dens and triggers mating behavior. [4] [12] Since food or water is not available close to dens, the snakes migrate to feeding grounds after mating. [4] In summer, the snakes move to mossy or marshy areas where they look for food. [8] Adult snakes feed only for 2 to 3 months during summer, whereas the young ones feed till the start of winter. [6] The adult primarily feed on ranid and wood frogs, and occasionally on mice and voles. [8] [6] The young snakes mostly feed on earthworms. [6] Soon after feeding, close to the end of summer, the adult snakes return to their dens for winter hibernation. [4] The young snakes, around one-year-old, spend more time in marshy areas to find food before the winter temperatures arrive and hibernate there as their small size makes them unnoticeable to predators. [8] During hibernation, the energy stored from summer feeding is used for body growth and maintenance to survive in subzero temperatures for months. [13]

Reproduction

In red-sided garter snakes, the breeding season usually begins in early spring and lasts for about a month. [9] These snakes exhibit a polygynous mating system, which means that males mate with multiple females each season. [14] During the mating season, male snakes form a mating ball near the dens and court females as they emerge. [4] Each female is courted by hundreds of males upon emergence. [15] [4] After mating, males and females move to mossy summer grounds where they find food and water and birth the offspring. [8] These snakes are viviparous and can birth about 30 young ones in one mating season. [4] Gestation period is about 3 to 4 months, and the young ones reach sexual maturity at 1.5 or 2 years of life. [8] In this species, the offspring are usually born before the adults re-enter winter dormancy, and immediately after birth, adult male and female snakes migrate back to their dens and re-enter hibernation in early fall before the temperature falls. [4] [8]

The reproductive system of male snakes includes testicles, epididymis, vas deferens, hemipenes, and renal sex segment. [4] Testes produce sperm that are transported by epididymis to the vas deferens, which then transfer the sperm to hemipenes. These snakes have a double penis with one testis supplying seminal fluid to each hemipenis. [4] Hemipenes are saclike organs that facilitate sperm transfer to the female. During winter, the segment of the vas deferens is used for sperm storage. [4] The function of the renal sex segment is to produce copulatory pheromones and the granules for formation of a copulatory plug. [16] [4] The female reproductive system consists of ovaries, an oviduct, and cloaca. The ovaries and oviducts are long due to the streamlined body of the snake. Multiple follicles (eggs) are present on the elongated ovaries. After mating, it takes up to 6 weeks for sperm to travel through the oviduct and reach the developing follicles in the ovaries. [4]

Pre-copulatory behavior

The behavior and physiology of red-sided garter snakes is heavily influenced by seasonal changes in the environment. [15] Temperature is one of the most crucial factors in regulating the life cycle of this species. [10] During mating season, males emerge first, all together in big groups, whereas females emerge singly or in small groups around 1 to 3 weeks after the emergence of males. [10] [15] When females start to emerge, males begin to form mating balls where they gather around at the opening of the communal dens and start courting the females as soon as they emerge from dormancy. [4] The courtship from males can continue from minutes to hours, but due to vigorous courting from males, females typically mate within 30 minutes after emerging. [14] [4]

Mate selection and courtship

In T. s. parietalis, mating is largely based on the courtship tactics of males. [11] Males prefer to mate with females who are unmated so they check females for any evidence of previous mating by studying their pheromonal trails for presence of copulatory pheromones or a copulatory plug by tongue-flicking in female cloaca and chin-rubbing to transfer pheromones from skin or cloaca to vomeronasal organ to determine her mating status. [15] [4] [17] Males also display a preference for larger females with longer snout-vent length than smaller females. [15] [18] Increased female body length indirectly correlates to higher sexual receptivity as longer females have higher follicular development, which indicates increased receptivity. [18]

When a male finds a female attractive, male shows increased frequency of tongue-flicking, chin pressing, tail searching, body contractions, caudocephalic waving, and attempts to align his body and cloaca to that of females to increase his mating possibility. [15] [11] However, as the sex ratio during emergence is highly male-biased, it is possible that multiple males court the same females together. [4] This raises intrasexual competition between males and results in male-male combat to secure the mate where males try to keep other males away from the females by ‘tail wrestling’ in which they insert their tails between the female and other courting males to force them off. [19] [11] Larger males with uninjured basal spine are benefited in such combats as they have longer tails which help them push off smaller males easily. [11] Male who manages to keep his cloaca aligned with female the longest, reaches intromission. [15]

However, female snakes exhibit no preference while choosing a mate. Females do not play active role in courtship or compete for mates, however they do play an important role during intromission and copulation. [15] [18] After the male red-sided garter snake performs courtship behavior, if the female is sexually receptive, she remains steady, breathes rapidly, lifts her tail and gapes her cloacal opening. [15] However, if she is unreceptive, she will reject the advances by strongly vibrating her tail and moving away from the courting males. [15]

Mating

During intromission, the male attempts to roll up the female's tail with his tail, aligning his cloaca with the female, and widens her cloaca by attaching the hooks at the base of hemipenes to cloacal scales for locking their cloacas together. [15] [4] Then males insert one of their hemipenis bases into the female cloaca and start sperm transfer. [19] After sperm transfer, males deposit a thick translucent gelatinous copulatory plug in the female cloaca that seals the cloaca by attaching the jelly-like substance to the cloacal wall. [14] [15] [16] Average copulation lasts about 15 to 17 minutes, of which eight or more minutes are dedicated for sperm transfer and 2 to 5 minutes for the transfer of plug granules from the renal sex segment that aids in formation of mating plugs. [16]

Post-copulatory behavior

Sperm competition among males is induced due to copulatory plug, as the primary function of the plug is to prevent re-mating in females by maintaining a reproductive barrier that blocks the female cloacal opening for about 72 hours after mating. [14] [16] [7] Around that time, most females either become unreceptive or start migrating to feeding grounds immediately after mating to avoid any injury or suffocation due to the mass gathering of males, who stay at dens till the end of breeding season. [4] [20] [16] Along with mate-guarding the females, mating plugs also play an important role in initiating transfer of recently deposited sperm, evacuating stored sperm in the oviduct from previous matings, preventing sperm leakage, and acting as antiaphrodisiac in females. [7] [14] After copulation, female attractiveness reduces due to seminal fluid and plug granules ejaculated in the female oviduct, which alters female pheromones that determine their attractiveness and receptivity [16] Fewer males court these females to minimize the time spent on courting females who are not receptive as these changes can be determined by the female's pheromonal trails from miles away. [17] [16] Female attractiveness decreases due to the presence of copulatory pheromones rather than changes in sex-attractiveness pheromones. The duration of release of copulatory pheromones coincides with the duration of a copulatory plug. [17]

Sexual conflict

In T. s. parietalis, males prefer to have a longer copulatory duration for maximal sperm transfer and formation of a copulatory plug which aids in mate-guarding the female. If copulation lasts longer, males can produce larger plugs to reduce re-mating in females. [19] However, if the quality or quantity of sperm transfer and copulatory plug is not adequate, the frequency of re-mating increases. [21] [7] Copulatory plug mass is also influenced by male body size, female body size, and the number of prior mating in that season. [16] However, females prefer shorter copulation to prevent injury to their reproductive tract, suffocation, exhaustion, and risk of predation. [19] [20] [7] Female genitalia often bleeds during and after copulation as penetration of the basal spine harms cloacal tissues while locking genitals. [19] To shorten the copulatory period, female snakes perform axial rotation and roll their body to disturb cloacal alignment with males. They also use vaginal muscles and cloacal tissues to force males away. [19] Females also avoid large mating aggregations and prefer dens with fewer male pheromones to avoid distress or death due to exhaustion or forcible insemination. [20] [7] Females also display post-copulatory sexual selection by re-mating or using sperm stored from the prior mating season, which increases sperm competition. It is common in red-sided garter snakes to have multiple paternity of offspring mainly by using stored sperm. [21]

Related Research Articles

<span class="mw-page-title-main">Garter snake</span> Common name for North American snakes of the genus Thamnophis

Garter snake is the common name for small to medium-sized snakes belonging to the genus Thamnophis in the family Colubridae. Native to North and Central America, species in the genus Thamnophis can be found in all of the lower 48 United States, and nearly all of the Canadian provinces south of the Northwest Territories and Nunavut—with the exception of Newfoundland and Labrador. They are found from the subarctic plains of west-central Canada east through Ontario and Quebec; from the Maritime Provinces and south to Florida, across the southern and central U.S. into the arid regions of the southwest and Mexico, Guatemala and south to the neotropics and Costa Rica.

<span class="mw-page-title-main">Common garter snake</span> Species of snake

The common garter snake is a species of snake in the subfamily Natricinae of the family Colubridae. The species is indigenous to North America and found widely across the continent. There are several recognized subspecies. Most common garter snakes have a pattern of yellow stripes on a black, brown or green background, and their average total length is about 55 cm (22 in), with a maximum total length of about 137 cm (54 in). The average body mass is 150 g (5.3 oz). The common garter snake is the state reptile of Massachusetts.

<span class="mw-page-title-main">Sperm competition</span> Reproductive process

Sperm competition is the competitive process between spermatozoa of two or more different males to fertilize the same egg during sexual reproduction. Competition can occur when females have multiple potential mating partners. Greater choice and variety of mates increases a female's chance to produce more viable offspring. However, multiple mates for a female means each individual male has decreased chances of producing offspring. Sperm competition is an evolutionary pressure on males, and has led to the development of adaptations to increase male's chance of reproductive success. Sperm competition results in a sexual conflict between males and females. Males have evolved several defensive tactics including: mate-guarding, mating plugs, and releasing toxic seminal substances to reduce female re-mating tendencies to cope with sperm competition. Offensive tactics of sperm competition involve direct interference by one male on the reproductive success of another male, for instance by physically removing another male's sperm prior to mating with a female. For an example, see Gryllus bimaculatus.

<span class="mw-page-title-main">Internal fertilization</span> Union of an egg and sperm to form a zygote within the female body

Internal fertilization is the union of an egg and sperm cell during sexual reproduction inside the female body. Internal fertilization, unlike its counterpart, external fertilization, brings more control to the female with reproduction. For internal fertilization to happen there needs to be a method for the male to introduce the sperm into the female's reproductive tract.

<span class="mw-page-title-main">Hemipenis</span> Male sex organ in squamate reptiles

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<span class="mw-page-title-main">Narcisse Snake Dens</span> Wildlife management area in Manitoba, Canada

The Narcisse Snake Dens is a provincial wildlife management area located in the Rural Municipality of Armstrong about 6 km (3.7 mi) north of Narcisse, Manitoba. The dens are the winter home of tens of thousands of red-sided garter snakes. These pits are the largest known concentration in the world of this particular type of snake. Their winter dens are caverns formed by the area's water-worn limestone bedrock. In the spring, they come up from their dens to the snake pits, where they mate, then they disperse into the nearby marshes for the summer.

<span class="mw-page-title-main">Sexual conflict</span> Term in evolutionary biology

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The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system. Unlike most organ systems, the sexes of differentiated species often have significant differences. These differences allow for a combination of genetic material between two individuals, which allows for the possibility of greater genetic fitness of the offspring.

<span class="mw-page-title-main">Mating plug</span> Gelatinous secretion used in the mating of some species

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Sexual antagonistic co-evolution is the relationship between males and females where sexual morphology changes over time to counteract the opposite's sex traits to achieve the maximum reproductive success. This has been compared to an arms race between sexes. In many cases, male mating behavior is detrimental to the female's fitness. For example, when insects reproduce by means of traumatic insemination, it is very disadvantageous to the female's health. During mating, males will try to inseminate as many females as possible, however, the more times a female's abdomen is punctured, the less likely she is to survive. Females that possess traits to avoid multiple matings will be more likely to survive, resulting in a change in morphology. In males, genitalia is relatively simple and more likely to vary among generations compared to female genitalia. This results in a new trait that females have to avoid in order to survive.

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Cryptic female choice is a form of mate choice which occurs both in pre and post copulatory circumstances when females in certain species use physical or chemical mechanisms to control a male's success of fertilizing their ova or ovum; i.e. by selecting whether sperm are successful in fertilizing their eggs or not. It occurs in internally-fertilizing species and involves differential use of sperm by females when sperm are available in the reproductive tract.

<span class="mw-page-title-main">Copulation (zoology)</span> Animal sexual reproductive act in which a male introduces sperm into the females body

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References

  1. "Red-sided Gartersnake". Canadian Herpetological Society . Retrieved June 15, 2023.
  2. Rossman, Douglas Athon (1996). The Garter Snakes: Evolution and Ecology. University of Oklahoma Press. ISBN   978-0806128207.
  3. Thamnophis sirtalis at the Reptarium.cz Reptile Database
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Crews, David; William R. Garstka (1982). "The Ecological Physiology of a Garter Snake". Scientific American. 247 (5): 158–171. Bibcode:1982SciAm.247e.158C. doi:10.1038/scientificamerican1182-158. JSTOR   24966731.
  5. "NatureServe Explorer 2.0".
  6. 1 2 3 4 Rossman, Douglas Athon (1996). The Garter Snakes: Evolution and Ecology. University of Oklahoma Press.
  7. 1 2 3 4 5 6 Friesen, C. R. (2012). Patterns and mechanisms: Postcopulatory sexual selection and sexual conflict in a novel mating system (PhD thesis). Oregon State University.
  8. 1 2 3 4 5 6 7 Thinesen, Pamela Kay (1989). Seasonal trailing behavior and corticosterone levels in male red-sided garter snakes (Thamnophis sirtalis parietalis) (MSc thesis). Dissertations and Theses. Vol. 3916. Portland State University. doi: 10.15760/etd.5800 .
  9. 1 2 Lincoln, Julianna M., Megan L. Barlowe, Holly R. Rucker, M. Rockwell Parker. (2023). "Reconsidering Reproductive Patterns in a Model Dissociated Species, the Red-Sided Garter Snake: Sex-Specific and Seasonal Changes in Gonadal Steroidogenic Gene Expression". Frontiers in Endocrinology. 14: 1135535. doi: 10.3389/fendo.2023.1135535 . PMC   10040831 . PMID   36992803.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. 1 2 3 Lutterschmidt, Deborah I. (2012). "Chronobiology of reproduction in garter snakes: Neuroendocrine mechanisms and geographic variation". General and Comparative Endocrinology. 176 (3): 448–455. doi:10.1016/j.ygcen.2011.12.015. ISSN   0016-6480. PMID   22210163.
  11. 1 2 3 4 5 Mason, Robert T., Richard Shine, Tracy Langkilde. (2004). "Courtship Tactics in Garter Snakes: How Do a Male's Morphology and behavior Influence his mating success". Animal Behaviour. 67 (3): 477–483. doi:10.1016/j.anbehav.2003.05.007. S2CID   4830666.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  12. Lutterschmidt, Deborah I., Robert T. Mason (1 October 2009). "Endocrine mechanisms mediating temperature-induced reproductive behavior in red-sided garter snakes (Thamnophis sirtalis parietalis)". Journal of Experimental Biology. 212 (19): 3108–3118. doi:10.1242/jeb.033100. PMID   19749103. S2CID   35337853.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. Whittier, Joan M.; David Crews (1990). "Body Mass and Reproduction in Female Red-Sided Garter Snakes (Thamnophis sirtalis parietalis)". Herpetologica. JSTOR. 46 (2): 219–226. JSTOR   3892907.
  14. 1 2 3 4 5 Whittier, Joan M., Robert T. Mason, David Crews. (1985). "Mating in the Red-Sided Garter Snake, Thamnophis sirtalis parietalis: Differential Effects on Male and Female Sexual Behavior". Behavioral Ecology and Sociobiology. 16 (3): 257–261. doi:10.1007/BF00310989. JSTOR   4599775. S2CID   33478759.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  15. 1 2 3 4 5 6 7 8 9 10 11 12 Garstka, William R.; Brian Camazine; David Crews (1982). "Interactions of Behavior and Physiology during the Annual Reproductive Cycle of the Red-Sided Garter Snake (Thamnophis sirtalis parietalis)". Herpetologica. 38 (1): 104–123. JSTOR   3892366.
  16. 1 2 3 4 5 6 7 8 Shine, Richard; M. M. Olsson; R. T. Mason (July 2000). "Chastity belts in gartersnakes: the functional significance of mating plugs". Biological Journal of the Linnean Society. 70 (3): 377–390. doi: 10.1111/j.1095-8312.2000.tb01229.x . S2CID   4843692.
  17. 1 2 3 O'Donnell, Ryan P.; Neil B. Ford; Richard Shine; Robert T. Mason (October 2004). "Male Red-Sided Garter Snakes, Thamnophis sirtalis parietalis, Determine female mating status from pheromone trails". Animal Behaviour. 68 (4): 677–683. doi:10.1016/j.anbehav.2003.09.020. S2CID   28192328.
  18. 1 2 3 Hawley, Alexander W. L.; Michael Aleksiuk (1976). "Sexual Receptivity in the Female Red-Sided Garter Snake (Thamnophis sirtalis parietalis)". Copeia. 1976 (2): 401–404. doi:10.2307/1443979. JSTOR   1443979.
  19. 1 2 3 4 5 6 Friesen, Christopher R.; Emily J. Uhrig; Mattie Squire; Robert T. Mason; Patricia L. R. Brennan (2014). "Sexual Conflict over Mating in Red-Sided Garter Snakes (Thamnophis sirtalis) as Indicated by Experimental Manipulation of Genitalia". Proceedings of the Royal Society B: Biological Sciences. 281 (1774): 20132694. doi:10.1098/rspb.2013.2694. PMC   3843848 . PMID   24225467.
  20. 1 2 3 Shine, Richard; Ben Phillips; Tracy Langkilde; Deborah I. Lutterschmidt; Heather Waye; Robert T. Mason (July 2004). "Mechanisms and consequences of sexual conflict in garter snakes (Thamnophis sirtalis, Colubridae)". Behavioral Ecology. 15 (4): 654–660. doi: 10.1093/beheco/arh058 .
  21. 1 2 Friesen, C.R.; Kerns, A.R.; Mason, R.T. (2014). "Factors influencing paternity in multiply mated female red-sided garter snakes and the persistent use of sperm stored over winter". Behavioral Ecology and Sociobiology. 68 (9): 1419–1430. doi:10.1007/s00265-014-1749-0. S2CID   253819264.