Animal Interactions Responses to the biotic environment

INTRASPECIFIC AGGRESSIVE Agonistic Territorial Hierarchies CO-OPERATIVE Group formation Courtship/pair bonds Parental care

Agonistic behaviour Any behaviour related to fighting – includes aggressive and submissive behaviours Due to – Competition for resource – Maintaining territory – Maintaining dominance hierarchy Involves – Attacks – Threat displays (ritual and appeasement)

Territories Marked / defended area within the home range Feeding, mating &/or rearing young

Territories Reduces competition for resources Reduce disease and parasites Most successful individuals hold best territories Losers spread out and look elsewhere Some individuals may fail to attract a mate Safe protected home Can become familiar with home range May only defend a territory at breeding times

Maintaining Territories Animals may mark using urine, faeces or scent gland Howler monkey has a loud morning call Birds sing at dawn and dusk Crabs wave their claws

Hierarchies Pecking order (hens) Dominance (alpha) Subordinate appeasement Reduces serious fighting

It would seem that grooming behaviour is very important in maintaining social order

INTRASPECIFIC AGGRESSIVE Agonistic Territorial Hierarchies CO-OPERATIVE Group formation Courtship/pair bonds Parental care

Group Living Animal society – stable group of individuals of the same species that have cooperative relationships outside of mating and raising young.

Aggressive baboon troupe

Communication Diverse modes vital to social interactions Eg smells, vocalisations, visual displays Honeybees communicate through “dancing”

Advantages of Group Life Defence against predators Increase feeding efficiency, eg hunting Protection from elements Easy access to potential mates Insect societies take co-operation to extremes Clumping to conserve moisture / heat etc Confusion – shoals can confuse predators

Disadvantages of group behaviour Crowding increases competition & conflict Disease and parasites spread easily

Altruism Helping another individual for no reward. Individual sacrifices Individual sacrifices reproductive potential for the benefit of others in the group – Honeybees (worker bees don’t mate*) – Turkeys (younger brother helps with courtship*) – Naked mole rats (only mammalian eusocial group*)

Advantages of Altruism Kin selection Kin selection – altruism may be advantageous if individual is helping “related genes” - Inclusive fitness accounts for most altruistic behavior (help related genes survive) Reciprocal altruism A wolf may offer food to an unrelated wolf. Can be adaptive if the aided individual returns the favor in the future. Commonly used to explain altruism in humans (“pay it forward”?).

Mating Behavior Costs Time & energy Display can attract predators so feathers often lost after mating season, huge investment Calling can attract predators Benefits – improved mating, better offspring survival

Mating Behavior Promiscuous Promiscuous: no strong pair-bonds – many random mates Monogamous Monogamous: one male, one female (usually monomorphic species – sexes look similar) Polygamous Polygamous: one with many (usually dimorphic species) – Polyandry – Polyandry: one female, many males (females more ornate) – Polygyny – Polygyny: one male, many females (males more ornate)

Monogamous species such as these trumpeter swans are often monomorphic and difficult to distinguish from each other

Polygyny Male needs to attract females Male is more ornate

The queen bee mates with a number of drones – she is usually much larger than the males

Polyandrous Wilson’s phalaropes - the female is more ornate

Influences on Mating Behavior Rearing young  if young requires lots of food and care, then both parents tend to stay;  if young independent, males tend to leave Certainty of paternity  Males often guard females to prevent other males from copulating;  internal fertilization means an amount of uncertainty  more likely to stay if certain the offspring are theirs