In
zoology, copulation is
animal sexual behavior in which a male introduces
sperm into the female's body, especially directly into her reproductive tract.
This is an aspect of
mating
In biology, mating is the pairing of either opposite- sex or hermaphroditic organisms for the purposes of sexual reproduction. ''Fertilization'' is the fusion of two gametes. ''Copulation'' is the union of the sex organs of two sexually reprod ...
. Many animals that live in water use
external fertilization
External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body.
It is contrasted with internal fertilization, in which sperm are introduced via insemination and then ...
, whereas
internal fertilization
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 inte ...
may have developed from a need to maintain
gamete
A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...
s in a liquid medium in the
Late Ordovician epoch. Internal fertilization with many vertebrates (such as all
reptiles, some
fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...
, and most
birds) occurs via
cloacal copulation, known as cloacal kiss (see also
hemipenis
A hemipenis (plural hemipenes) is one of a pair of intromittent organs of male squamates (snakes, lizards and worm lizards). Hemipenes are usually held inverted within the body, and are everted for reproduction via erectile tissue, much like ...
), while
mammals copulate
vagina
In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...
lly, and many
basal vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...
s reproduce sexually with external fertilization.
In spiders and insects
Spider
Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...
s are often confused with
insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...
s, but they are not insects; instead, they are
arachnid
Arachnida () is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and vinegar ...
s.
Spiders have separate male and female sexes. Before mating and copulation, the male spider spins a small web and ejaculates on to it. He then stores the sperm in reservoirs on his large
pedipalp
Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") an ...
s, from which he transfers sperm to the female's genitals. The females can
store sperm indefinitely.
For primitive insects, the male deposits
spermatozoa on the substrate, sometimes stored within a special structure;
courtship involves inducing the female to take up the sperm package into her genital opening, but there is no actual copulation.
In groups that have reproduction similar to spiders, such as
dragonflies
A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threa ...
, males extrude sperm into secondary copulatory structures removed from their genital opening, which are then used to inseminate the female. In dragonflies, it is a set of modified
sternites
The sternum (pl. "sterna") is the ventral portion of a segment of an arthropod thorax or abdomen.
In insects, the sterna are usually single, large sclerites, and external. However, they can sometimes be divided in two or more, in which case the ...
on the second abdominal segment.
In advanced groups of insects, the male uses its
aedeagus, a structure formed from the terminal segments of the abdomen, to deposit sperm directly (though sometimes in a capsule called a ''
spermatophore'') into the female's reproductive tract.
In mammals
Sexual behavior can be classified into behavioral states associated with
reward motivation ("
wanting"), reward consummation aka pleasure ("liking"), and
satiety ("inhibition");
these behavioral states are regulated in mammals by reward-based sexual learning, fluctuations in various neurochemicals (i.e.,
dopamine −
sexual desire
Sexual desire is an emotion and motivational state characterized by an interest in sexual objects or activities, or by a drive to seek out sexual objects or to engage in sexual activities. It is an aspect of sexuality, which varies significantly f ...
aka "wanting";
norepinephrine −
sexual arousal;
oxytocin and
melanocortins −
sexual attraction), and gonadal hormone cycles and further influenced by
sex pheromone
Sex pheromones are pheromones released by an organism to attract an individual of the same species, encourage them to mate with them, or perform some other function closely related with sexual reproduction.
Sex pheromones specifically focus on ind ...
s and
motor reflex
Tendon reflex (or T-reflex) may refer to:
*The stretch reflex or muscle stretch reflex (MSR), when the stretch is created by a blow upon a muscle tendon. This is the commonly used definition of the term. Albeit a misnomer, in this sense a common ...
es (i.e.,
lordosis behaviour) in some mammals.
These behavioral states correlate with the phases of the
human sexual response cycle: motivation − excitement; consummation − plateau and orgasm; satiety − refraction.
Sexual learning (a form of
associative learning
Learning is the process of acquiring new understanding, knowledge, behaviors, skills, values, attitudes, and preferences. The ability to learn is possessed by humans, animals, and some machines; there is also evidence for some kind of l ...
) occurs when an animal starts to associate bodily features, personality, contextual cues, and other stimuli with genitally-induced sexual pleasure.
Once formed, these associations in turn impinge upon both sexual wanting and sexual liking.
In most female mammals, the act of copulation is controlled by several innate neurobiological processes, including the motor sexual reflex of
lordosis
Lordosis is historically defined as an ''abnormal'' inward curvature of the lumbar spine. However, the terms ''lordosis'' and ''lordotic'' are also used to refer to the normal inward curvature of the lumbar and cervical regions of the human spin ...
.
[PFAFF Donald W. , SCHWARTZ-GIBLIN Susan, MACCARTHY Margareth M. , KOW Lee-Ming : Cellular and molecular mechanisms of female reproductive behaviors, in KNOBIL Ernest, NEILL Jimmy D. : The physiology of reproduction, Raven Press, 2nd edition, 1994] In males, the act of copulation is more complex, because some learning is necessary, but the innate processes (retrocontrol of penis intromission in the vagina, rhythmic movement of the pelvis, detection of female pheromones) are specific to copulation. These innate processes direct heterosexual copulation.
[MEISEL Robert L. , SACHS Benjamin D. : The physiology of male sexual behavior. in KNOBIL Ernest, NEILL Jimmy D. The physiology of reproduction, Raven Press, 2nd edition, 1994] Female lordosis behaviour became secondary in
hominidae and is non-functional in humans.
[Dixson A.F]
Primate sexuality: Comparative studies of the Prosimians, Monkeys, Apes, and Human Beings
Oxford University Press, 2nd edition, 2012. Mammals usually copulate in a dorso-ventral posture, though there are some primate species that copulate in a ventro-vental posture.
Most mammals possess a
vomeronasal organ that is involved in pheromone detection, including
sex pheromone
Sex pheromones are pheromones released by an organism to attract an individual of the same species, encourage them to mate with them, or perform some other function closely related with sexual reproduction.
Sex pheromones specifically focus on ind ...
s.
Despite the fact that humans do not possess this organ, adult humans appear to be sensitive to certain mammalian pheromones that putative
pheromone receptor proteins in the
olfactory epithelium
The olfactory epithelium is a specialized epithelial tissue inside the nasal cavity that is involved in smell. In humans, it measures
9 cm2 and lies on the roof of the nasal cavity about 7 cm above and behind the nostrils. The olfactory ...
are capable of detecting.
While sex pheromones clearly play a role in modifying sexual behavior in some mammals, the capacity for general pheromone detection and the involvement of pheromones in regulating human sexual behavior has not yet been determined.
The duration of copulation varies significantly between mammal species, and may be correlated with body mass, lasting longer in small mammals than in large mammals.
[Stallmann, Robert R., and A. H. Harcourt.]
Size matters: the (negative) allometry of copulatory duration in mammals
" Biological Journal of the Linnean Society 87.2 (2006): 185-193.
See also
*
Pelvic thrust
The pelvic thrust is the thrusting motion of the pelvic region, which is used for a variety of activities, such as dance or sexual activity.
Sexual activity
The pelvic thrust is used during copulation by many species of mammals, including hum ...
Notes
References
Bibliography
*
* Møller, A. P., and T. R. Birkhead.
Copulation behaviour in mammals: evidence that sperm competition is widespread" Biological Journal of the Linnean Society 38.2 (1989): 119–131.
* Birkhead, Timothy R., L. Atkin, and A. P. Møller.
Copulation behaviour of birds" Behaviour 101.1 (1987): 101–138.
*
*
*
*
*
*Carlson, Debra A
Reproductive biology of the coyote (Canis latrans): integration of behavior and physiology Utah State University, 2008.
*Castro, Ana Mafalda Lopes Sardica Velez
Mexican gray wolf courtship and mating: behavior & basic endocrinology during breeding season Diss. Universidade de Lisboa. Faculdade de Medicina Veterinária, 2016.
* Szykman, Micaela, et al.
Courtship and mating in free-living spotted hyenas. Behaviour 144.7 (2007): 815–846.
* Dixson, Alan F.
Baculum length and copulatory behavior in primates. American Journal of Primatology 13.1 (1987): 51–60.
{{Animal sexual behavior
Animal sexuality
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