Wk13 Reptile repro Flashcards
Oviparous breeding in reptiles
- Laying an egg
- Shell is there but its a soft and rubbery shell - bite their way out most of the time
Eggs laid by the female then incubated in nest/burrow by ground temperature for a couple of months before hatching
Viviparous breeding in reptiles
- Live bearing
Delivered as live young, eyes open and can eat on its own since born
Oviviparous
- Reptiles that produce egg inside of the body and embryos continue to develop
Can be delivered as live young with amniotic sack around them after developing inside
Anatomy of females- reptiles
- Paired ovaries and paired oviducts
- Follicles of the ovary caudal to the gallbladder
- Wall of uterus is very thin (glad wrap)
Cesarian - walls will heal on their own (don’t have to suture them)
Anatomy of reptiles - males
Paired testicles - caudal to the gall bladder as well
Anatomy - female: the oviducts- what is the role
- Role
- Egg transport
- Albumin, protein and calcium for the egg formation
- Viviparous reptiles
Uterine section is thickened and muscular
Male anatomy- the hemepenes
What is a phallus
- All snakes and lizards have the hemepenes
- Mating organ - if its long (about 4 scales) will be male
○ This is a general rule - females can have long hemepenes too…
The males will invert this and pop the hemepenes out and ejaculate into the female cloaca and into the vagina - female vagina holds it in there for ejaculation
- Mating organ - if its long (about 4 scales) will be male
- In turtles:
They have a phallus (similar to a penis) instead of a hemepenes
Physiology of breeding: the 2 types of breeding patterns
2 broad patterns of reproductive behaviour
** - Associated breeding pattern**
○ Correlated with gonadal steroid concentrations and in females, is associated with ovulation
** - Dissociated pattern: not mediated by gonadal steroid** concentration but by environmental factors e.g. Temperature
○ Males - mating occur at time when gonadal activity it low and hence stored gametes produced in previous breeding season are used
○ Females - mating occurs early in the breeding season and sperm are stored for fertilisation of ova that subsequently develop
Some cases will store from several years ago
Energy allocation in females during reproduction
- Processes:
- Folliculogenesis
- Vitellogenesis
- Egg/foetus storage
- Massive energy expenditure - up to 40% body mass devoted to it
- Reduced energy input = reduced appetite/fairly quite
Therefore activity often reduced
Breeding season of reptiles:
- tropical species
Temperate species
- Tropical: Continuous or influenced by other environmental factors such as rainfall or season variation
- Temperate: reliant on ambient temperature for embryogenesis
- Thus seasonal
Day length, temperature changes (particularly extreme changes) and social interactions all effect it
- Thus seasonal
Parthenogenesis - what is this
- Asexual reproduction in which an egg develops without fertilisation by spermatozoa
Is it asexual reproduction or due to sperm storage?
Captive breeding in reptiles
What do we need for successful captive breeding requirements
- Complicated by dissociated breeding behaviour
- When do we mate?
- When male is producing fresh sperm?
- When female is about to ovulate?
- Successful breeding requirements
- Healthy animals
- Environmental cues
- Depends on:
Species, aggression, experience of people keeping the reptiles
Clutch size of reptiles:
- Huge amount of variation
Bearded dragons - lay about 20-30 eggs in a hit
Gestation of reptiles
- Difficult to determine in reptiles
- Lots of variation in species
- Environment (especially temperature)
- 50-65 days for egg laying species
- 100-160 days for live-bearing species
- But when laying the eggs, the eggs won’t hatch for another 2 months or so
Need suitable substrate to lay their eggs in (sand/nest etc.)
