Primate Ecology: Habitats, Niches and Diet

Primate Ecology

• Primate ecology explores the interactions of primates with their environment, including other organisms
• Most primates inhabit tropical environments
• A diverse set of primate habitats are in tropics
• Gallery forests exist alongside rivers
• Primary rainforests have high rainfall, while savannahs have less
• Habitat variables include altitude, seasonality, and soil

Fundamental Concepts of Primate Ecology

• A niche is an organism's ecological role in its environment
• Niche describes how species live in an ecosystem
• Niche involves conditions for a species' persistence and its environmental impact
• Niche descriptions are multidimensional, covering diet, locomotion, activity, ranging patterns, and predators
• Niche axes partly describe how species avoid direct competition

Diet

• All primates need protein, carbohydrates, fat, vitamins, and water
• Diet refers to the combination of foods that satisfy nutritional needs
• Main dietary categories include:
  • Faunivore/Insectivore (animals/insects)
  • Gummivore (gum and saps)
  • Frugivore (fruit)
  • Folivore (leaves)
• "Omnivore" is not meaningful, because all primates eat fruit except tarsiers
• Tarsiers' diet is 100% animals

Ranging Patterns

• Home range is, where a primate or group lives
• Home ranges are consistent over time
• Animals return to resources like food and sleeping sites
• Home ranges may overlap
• Most primates, except humans are nomadic
• Territory is a defended boundary of a home range
• Territory excludes conspecifics and provides exclusive access
• Only some primates are territorial
• Maintaining a territory is costly
• Habitat influences ranging patterns

Locomotion and Activity

• Efficient locomotion shapes ranging behavior
• Substrate use influences locomotion
• Time is divided in three ways:
  • Diurnal (active during the day)
  • Nocturnal (active during the night)
  • Cathemeral (active during day and night)

Predation Risk Reduction

• Two strategies to reduce predation risk exist
• Crypsis is the ability to conceal through camouflage
• Camouflage associates with nocturnal, solitary, or small-group primates
• Group living reduces predation risk for these three reasons:
  • Easier detection with more eyes and ears
  • Deterrence by mobbing predators
  • Dilution of risk, lowering individual probability of being eaten

Interspecies Interactions & Competition

• Primates often share habitats
• Space and resources become divided
• The Competitive Exclusion Principle states no two organisms have identical ecological niches
• Requirements may substantially overlap
• One species will eventually outcompete another
• Coexisting species differ in their niche
• Interspecies competition can result in the following:
  • Niche overlap area incorporation into a niche
  • Local extinction of one species.
  • Division occurs between the two species.
• Realized niche shift happens and may lead to character displacement, enabling sympatric coexistence

Ecological and Community Dynamics

• Ecological release, a form of competitive release, involves niche expansion upon removal of a constraining variable
• Community ecology studies interspecies interactions in communities across spatial and temporal scales
• It includes distributions, structure, demography, abundance and coexisting population interactions
• Communities are assemblages of interacting species populations within a habitat
• Disease ecology studies host behavior and ecology interactions, with pathogen biology
• Infectious disease transmission involves environment, parasite, and host
• Microbiome refers to microbial taxa associated with a primate host

Primate Socioecology Framework

• Sociobiology examines behavior in an evolutionary context, including social evolution
• Socioecology examines how ecology affects behavior

Benefit of Group Living

• Reduced predation risk evolves as way to reduce risk

Group Size & Competition

• Predation risk decreases as group size increases
• Resource competition increases as group size increases
• Predation risk and resource competition intersection determines group size
• Variation found in group size is explained by resource competition and predation risk
• Competition type varies by resource distribution:

Competition: Contest vs. Scramble

• Contest competition includes when monopolizing patches benefits some more than others
  • Resulting in unevenly distributed costs and hierarchies
• Scramble competition occurs when food is evenly distributed, negating the benefits of monopolization
  • "Early bird catches the worm"; Abundance influences competition amount, not type
• Group living costs rises equally with group size

Costs of Group Living

• Costs include direct competition, time spent searching for food, travel, coordinating activities, and disease transmission
• Gregarious animals have adapted ways to live in close proximity

Other Benefits to Group Living

• Defense of resources benefits by larger groups

Socioecology & Resource Distribution

• Distribution of resources and risks shapes social relationships

Sociobiology & Reproduction

• Reproduction is limited by resources
• Female reproductive success is most limited by food
• Male reproductive success is most limited by females
• Reproductive success relies on females in estrus, heat and heightened sexual activity around ovulation

Socioecology Model

• Distribution of Resources influences on Distribution of Females influences on Distribution of Males influencing Social System
• Ecology influences social system through group size

Social Systems

• Five Categories -Solitary is rate in Primate -Pair (family) -Single male -Multi-male single female -Multi-male multi-female
• Cohesive groups feed, travel, sleep together
• Dispersed individuals forage separately, but sleep together, for efficiency
• Fission-fusion dynamics

Mating systems

• Mating system reflects individual sexual partners -Monogamy: one male and one female which is often paired -Polygyny: one male with multiple females often single-male -Polyandry: one female with multiple males or multi-male single-female -Polygynandry: multiple partners for both male and females usually multi-male multi-female

Defining Sex in Biology

• Sex in vertebrates relies on genes and environmental influences
• This diversity varies among closely related species
• Sex definition relies on -Chromosomes (XX for female or XY for male) -Anatomy (external genitalia) -Pregnancy and Parental care -Behavior -Gamete Size
• Some species change sex to fit the need

Sexual Selection & Competition

• Sexual selection is natural selection due to competition for mates or mate attraction

Limits & Reproductive Success

• Limits on offspring numbers exist with males
• Most mammals, most females can mate and imbalance can lead to male competition
• Female primates maximize RS through increasing offspring survival rather than mating numbers

Sexual Selection Factors

• The most limiting factor of reproductive success differs between sexes
• Mate distribution defines competition type

Types of Sexual Selection

• Intrasexual includes competition within a sex -It also includes traits of fighting ability, endurance and sperm competition -Intrasexual selection commonly results in sexual dimorphism
• Mate Choice involves being chosen by the opposite sex -It includes ornamentation, courtship, service and friendship
• Sexuaul Conflict means competition for mating and reproduction control -It also includes vaginal tract, estrus synchrony and sexual coercion traits

Male Strategies in Evolution

• Male reproductive lifespan is short
• Infanticide gives killer reproductive advantage if the infant is unrelated -Also by weaning leading to chances of mating with the mother
• Female counterstrategy = confusing paternity

Natural Selection

• Variation, heredity, differential reproduction is also called sexual selection
• Mating competition causes differences

Sexual Selection - Old vs New

• Old view was males fight, females chose and reversed marmoset roles
• Now know females compete for access including benefits
• "Promiscuity" is a non discriminating reproductive strategy

Alternative Tactics

• Also includes behavioral, morphologies and/or gender differences

Altruism

• Altruism is when animals increase each other's fitness at their own expense
• The altruistic interaction is between two or more, lowering one but beneficiary increases
• Altruists not forced by aggression with exmaples in praire dogs

Models of Altruistic Behavior

• Group Selection
  • Members of a altruistic group have higher fitness than others
  • There are criticisms of cheaters prospering in Altruists
• Kin Selection
  • Inclusive fitness or Selective interaction among kin to promote evolution of traits
  • Hamilton's rule (br>c) and benefits must be discounted

Gene Sharing

• Genes are shared two individuals through descent

Cooperative Nature

• Reciprocal altruism allows long term relationships
  • Prairie dogs alternate alarm calling

Group Cooperation

• Grooming including Ectoparasite removal and negotiating cooperation is diverse

Access and Advantage

• Grooming allows access to young infants
• Newborn source of attention and Commodity affects by infant availability during durations
• Defense, tolerance and predators

Alliances and Morality

• Coalitions are temporary with grooming linked to support
• Primates tolerate theft
• Cooperation in hunting of colobus chimpanzees

Humans

• Group Selection for humans causes
  • Kin Selection & Mismatch -Indirect Reciprocity and Status facilitation plus cooperation
• Punishment and Shame leads to altruistic human
• Alliances and hunting cooperation common

Communications

• Primate Vocals
  • Primate Intelligence is found in their brains Primate vocal and calls are used to communicate

Evolutionary History

• Evolution
  • Primate calls refer external references Primate language is linked in its ancestors

Early Primates

• Primates were driven by earth change
• Primates survived mass extinction
  • Eocene epoch warmer climate

Theories

-Mammal Adaptive theories -Primate Evolutionary Theories

The Rise of Species

• Primates rose again after being gone
  • Climate change - Rise of hominoids in afro and abria

Human traits

• Primates grew larger and developed larger intelligence

Cooperation

Chimpanzees assist for tasks - Primates pass these skills down to generations