lecture 10 studyguide - soical behaviours.pdf

1 2 3 Pros and Cons of Grouping: Grouping offers several advantages, including safety in numbers, as grouped individuals are less vigilant for predators compared to solitary conspecifics. This is due to the increased likelihood of predator detection and the ability for one individual to warn many ot...

1 2 3 Pros and Cons of Grouping: Grouping offers several advantages, including safety in numbers, as grouped individuals are less vigilant for predators compared to solitary conspecifics. This is due to the increased likelihood of predator detection and the ability for one individual to warn many others of danger (detection effect), as well as the dilution effect, where grouping makes it less likely for any given individual to be preyed upon. Additionally, group living provides protection from the elements, increases feeding efficiency by facilitating food finding, and offers easy access to potential mates. However, there are drawbacks to grouping, such as increased competition for resources like food, water, and shelter, as well as mate competition, the risk of cuckoldry, cannibalism of young, and the spread of diseases and parasites. Furthermore, animals in groups are more visible to predators, increasing the risk of predation. 4 5 6 The Selfish-Herd Effect: The selfish herd effect is a phenomenon where individuals reduce the risk of predation by moving to specific positions within a group. This involves adopting possible movement rules and modifying behavioral responses to impending attack based on one's position within the group. Understanding the attack strategy of predators is crucial in determining prey escape strategies within a selfish herd context. Individuals may position themselves at the center of a large group to avoid fly bites and potential subsequent infections via the selfish-herd effect. 7 8 Group living requires learning social structure and membership, including understanding interaction dynamics and hierarchies within the group. Different species exhibit diverse social structures and behaviors, ranging from solitary societies to permanent groups with complex structures. These social organizations evolve based on factors such as food availability, terrain, and predation pressure. 9 10 Various types of social groups have evolved in response to environmental factors. Solitary societies exist alongside polygynous groups (harem) and permanent groups with complex structures found in marsupials, ungulates, elephants, cetaceans, primates, and some carnivores. These groups may exhibit dominant pair structures or matrilineal societies where ancestry is traced through the mother's family. 11 In matrilineal societies, ancestral descent is traced through maternal lines, while in matriarchal societies, a female elder has absolute authority over the family group. Examples include lions, where matrilineal societies are observed, and elephants, which exhibit matriarchal social structures. 12 13 14 15 16 17 Eusocial animals exhibit complex social structures characterized by cooperative care of juveniles, reproductive division of labor, and overlap of generations. This phenomenon is observed in species like naked mole rats, where only one female (the queen) and a few males reproduce, while the rest of the colony functions as workers. 18 19 20 21 22 23 Territorial behavior involves the defense of physical space containing resources necessary for survival and reproduction. While territoriality provides benefits such as resource access and mating opportunities, it also requires energy expenditure and may involve conflicts with conspecifics. 24 25 26 27 28 29 30 31 32 33 34 Mating systems vary between species and are influenced by ecological factors and the needs of offspring. They can include promiscuous, monogamous, or polygamous arrangements, each with its own implications for social organization and behavior. These topics provide insights into the diverse ways in which animals organize themselves socially, adapt to their environments, and interact with conspecifics. Understanding social organization is crucial for comprehending animal behavior, ecology, and evolution. 35 36 37 38 39 40 Pros and Cons of Grouping: Pros: Safety in Numbers: Grouping offers protection from predators as individuals are less vigilant when in a group. This increases the likelihood of predator detection and allows for warning signals to be spread efficiently among group members. Increased Feeding Efficiency: Group living can enhance feeding efficiency by facilitating food finding. Individuals in a group can share information about food sources and cooperatively forage, leading to better resource acquisition. Protection from Elements: Group living provides warmth and shelter, especially in harsh environments. Animals can huddle together for warmth and protection against adverse weather conditions. Ease of Access to Mates: Living in groups offers individuals easier access to potential mates. Social interactions within the group can facilitate mate choice and reproductive opportunities. Cons: Competition for Resources: Group living often leads to increased competition for resources such as food, water, and shelter. This competition can result in conflicts and hierarchies within the group. Increased Risk of Disease Spread: Close proximity in group living environments can 41 facilitate the spread of diseases and parasites among individuals. This can pose health risks to group members and reduce overall fitness. Mate Competition: In groups, there may be heightened competition for mates, leading to conflicts and reproductive challenges. Dominant individuals may monopolize mating opportunities, leaving subordinate individuals with limited reproductive success. Predator Attraction: Larger groups may attract predators due to increased visibility and detectability. Predators may target group members more efficiently, posing a threat to individual safety. Diverse Social Groups and Social Behavior: Different species exhibit diverse social groups and behaviors, which evolve in response to various ecological factors. These social organizations range from solitary societies to complex group structures. Factors influencing social behavior include food availability, terrain characteristics, and predation pressure. Examples of social groups include solitary individuals, polygynous groups, and permanent groups with dominant pair structures or matrilineal societies. Eusociality: Eusociality is a complex form of social organization characterized by cooperative care of juveniles, reproductive division of labor, and overlap of generations. This phenomenon is observed in certain insect species such as ants, bees, and termites, as well as in some vertebrates like naked mole rats. Eusocial colonies typically have a reproductive queen or dominant individuals, with sterile workers performing specialized tasks to support the colony. Territoriality: Territoriality refers to the behavior of defending a physical space containing resources essential for survival and reproduction. Territories may include nesting sites, feeding areas, or mating grounds. Territorial behavior involves marking and defending boundaries through various means such as scent marking, vocalizations, and physical displays. Territoriality provides benefits such as resource access and exclusive mating opportunities but also requires energy expenditure and may lead to conflicts with conspecifics. The Lek Paradox: The lek paradox refers to the evolutionary puzzle surrounding the maintenance of genetic variation in traits associated with mate choice within lek mating systems. Leks are areas where males gather to perform elaborate courtship displays to attract mates. The paradox arises because if females consistently choose the same highly preferred traits in males, genetic diversity should decrease over time. However, strong selection for specific traits should lead to fixation rather than maintenance of genetic variation. Several hypotheses, such as fluctuating selection, genetic capture, and conflicting female preferences, attempt to explain this phenomenon. Mating System, Mate Choices, and Social Systems: Mating systems vary between species and are influenced by ecological factors, 41 reproductive strategies, and social dynamics. These systems can include promiscuity, monogamy, or polygamy, each with its own implications for mate choice and social organization. Mate choices often involve complex behaviors and interactions, such as courtship displays, mate guarding, and parental care. In primate societies, mating systems and social organization are driven by external ecological factors and the needs of offspring, leading to diverse mating strategies and social structures. 41