Behaviour withRespect to Hormonesv Animal behaviour is closely associated with stimuli aswell as hormones.Hormone:o A chemical substance whichis released from endocrine gland and travels by blood to the target pointcalled as hormone.v In 1992, Nyby Et Al. manipulate testosterone in malemouse. He studies the effect of testosterone on social and sexual behaviour ofmouse.v For this purpose, surgery, hormonereplacement, manipulationof hormonesand concentration of hormones,these tools was used.
v Because stimuli transfer the message to the CNS to perform differentactivities and CNS send the message to the target cell by nerves orhormones.Hormones are secreted by endocrine glands and are mostly liquid innature,travel by blood to the finel point.Effects of these horrmonel responsewe can see in the form ofspecific animal behaviour.
v E.g. Sexual attraction by release of pheromones.
v The hormones may be used to generate social behaviour,reproductive behaviour and aggressive behaviour,etc.v When we talk abouthormones we should keep in mind that the CNS is directly involved in therelease of any hormone and ultimatefate of the hormone like afterits function it will be degraded or recycled.v All types of informationabout hormone is transcribed by brain or CNS, as it affects the target cells ortissue,the resulting pattern of action will be occur and we named this patternof actions as Animalbehaviour.v When we say that an animalis foraging then I would like to clear that it is an animal behaviour,pattern of actions. Becausedifferent hormones produce the sensation of hunger.so, it is cleared from thisdiscussion that animal behaviour is a combination of stimuli hormones andeffectors.
Certain other factors may also be involved like environment andnervous system.Hormones have different effects and levels in different stagesof the life of an animal.v EXAMPLE; The level of sex hormones is higher at puberty of animaland animal have maximum mating capability.vThere are different behavioursaffected by hormones some of which are given below;v 1.Hormones andreproductive behaviour.v 2.Hormones and sexdifferenciation.v 3.
Hormones andmaternal behaviour v 4.Hormones andaggressive behaviourHormones and reproductive behaviourv This type of behaviour isseasonal based,during breeding season the level of sex hormones will beincreased.As melatoninsecreted by pineal gland will inhibit the growth of sex organs during breedingseason.The pituitary hormones like FSH, LHand Prolactinhormone effects the growth of ovary in female.These hormones are alsoresponsible for ovulationduring menstrual cycle.v The egg laying capability of female is due to the effect of LH hormone and after egglaying the incubationbehaviour of female is also affected by Prolactin hormone.
As a result of the effects ofthese hormones the female perform all the reproductive behaviour like mating,egglaying, incubation andfertilization.After fertilization the development of embryo is also controlledor affected by a set of hormones.v During pregnancy the food demand of female animal becomes higher dueto feeding of young one and in many cases female mostly rests during these daysand male provide food to his female partner.
So, ultimately during breedingseason the foraging behaviour is also affected by hormones.The sexdetermination is also controlled by hormones, as given below; Hormonesand sex determinationv The behaviour for mating of male and female is helped out byhormones.During breeding season the female releases different pheromones which attractthe male to herself for mating.Anddue to increased level of testosterone hormone inmale animals they also perform different actions to attract female formating. E.g. male birds singing ordancing.
v Hormones produce different changes in body stature of female or male likeduring menstrual cycle, the changes in uterine wall or change in male or femalegenital tract.v Next we see how the motherand father have specific behaviour;v Hormones and maternal behaviour;v Inmost vertebratesthe mother has specific behaviour tocare her young ones.The mother feeds her young one and also care his youngone. In case of feedingwith milk pituitary hormone is directly involved because prolactin is involvedinthe formation of mammaryglands,which produce milk.v If the prolactin is stopped the feeding behaviour ofmother will also be stopped.In case of mice the LH and progesterone also produces the nest building behaviour forprotection of her young one.vFrom all above discussion it iscleared that the animal behaviour is designed by specific hormones.Molecularlevelof hormones and animal behaviour;vThe hormones are commonly protein innture and each hormone is coded by a specific gene.Gene is a specific sequence ofnucleotides present at specific part of DNA.When the hormone is producedthe CNS i.e hypothalamus gives destiny to this hormone.vThese animal behaviours controlled byhormones helpan animal in its survival and increase its reproductive rate.v Ultimately the successful behaviourcontrolled by hormones helps animal to gain such features that give it successin evolution.Due to having these fruitful pattern of actions,nature selectsit.So indirectly hormones helps innatural selection.