Behavioral ecologists investigate following aspects of animals:
- Orientation and navigation: How animals find their way?
- Habitat selection: How they find a place to live?
- Foraging behavior: What foods they select for eating?
- The ways in which behavior can influence population biology.
1. HABITAT SELECTION
The animal’s choice of a place to live is called habitat selection. Two types off. tors affect the habitat selection.
1. Physiological tolerance limits, of the animals: It is determined by the
evolutionary history of the species. It involves temperature, humidity, water salinity, and other environmental parameters.
choices of the animals: The choice of the animals is based on available food resources, nest sites, lack of predators and past experience.
Woodland deer mice cannot tolerate high temperatures in the field environment. Therefore, they live in forests rather than fields. It is physiological limit of these animals. But they prefer areas with larger trees within the West. These trees pro ide more food in the form of acorns and beechnuts. They also provide better shelter and more nest sites. It is their choices.
2. FORAGING BEHAVIOR
The process of locating food resources is called foraging behavior. All animals must consume food to survive. They spend most of their time in finding and consuming food. Animals face the following choices:
- What items are included in the diet?
- Food is not distributed evenly i.n the environment. It occurs in patches or clumps. What path should an animal take between patches? How should it locate new patches of food?
- The food is reduced in patches. Therefore, when should the animal depart from that location and seek another patch of food? Examples
- Hummingbirds and different species of bees visit clumps of flowers, They obtain nectar. They must make these decisions.
- Owls eat small rodents in different habitats. These rodents are present in fields and forests. They must make similar decisions.
The animals do not calculate their personal energy budgets. But there are energy costs and gains for finding and consuming food. The energy costs include energy needed to search for food. Energy is used to follow and handle the food. Energy is required to digest the food. The energy gain from digesting a particular set of food items must exceed the costs for survival of an animal. Thus, a praying mantis spends energy to locate a moth, to strike the moth, to remove the moth’s wings, to consume the moth’s body and to digest the meal. The mantis will survive if the energy derived from digesting the moth is greater than these costs. They also needed energy for searching a mate or laying eggs.
Specialists and Generalists
- Specialists: Some animals are specialists for diet and habitat selection.
Evolution has made them very efficient for using particular resource. Koala is an Australian marsupial mammal. It eats the leaves of certain species of eucalyptus trees. Its digestive system is adapted for deriving energy from the leaves of these trees. Thus it is a specialist. It can exploit a particular resource only. But it is very risky. Suppose plant disease kills trees of the eucalyptus species. The koalas will not be able to survive.
- Generalists: The animals that can eat variety of foods or living organism
,in a variety of habitats are called generalists. These animals can survive under a wide range of conditions. Humans are a good example of a generalist species. Some pest species, like European starlings were introduced into the United States a century ago. They are now living in almost every available type of habitat. The generalists have a disadvantage. They eat and live everywhere. Therefore, they face competition from other organisms. Such competition is not faced by specialists.