Sponge spawning

Sponge spawning

Coral spawning - sperm

Coral spawning - eggs

Coral spawning - eggs

Palolo worm (polychaete annelid)

Consist of anterior atoke and a posterior epitoke

On two or three nights, epitokes break free from the atokes and swim to the surface

Mass spawning of palolo worms

Palolo worms swarming

Palolo worms

Palolo worms

Uterine horns in some mammals

Acanthocephalans (spiny-headed worms

Acanthocephalan in situ

Acanthocephalan reproduction

Males have an eversible penis After mating with a female, the males

neatly cap the female gonopore with cement

Males will also attempt to cement shut the gonopores of other males!

Last male advantage

In a number of animals with internal fertilization, the last sperm to enter the female reproductive system have the advantage

Examples are birds and insects

Damselflies mating

Dragonflies mating

Dragonflies and damselflies Male curls his abdomen to transfer sperm

from the ninth abdominal segment to accessory genitalia on the second abdominal segment

The male and female adopt the wheel position to transfer sperm to the female

Before copulating, the male will scoop out any pre-existing sperm from the female’s reproductive tract

Males sometime hold on to the female while she oviposits

Other males hover around the female during oviposition

Onychophora

Onychophora reproduction

Male deposits a spermatophore (a protective structure enclosing sperm) on the forest floor

A female stumbles across a stomatophore and appresses her ventral side to the spermatophore

The spermatophore causes her ventral body wall to rupture (ouch!), providing a means for sperm to enter her body