BIOL3045 Study Guide - Final Guide: Cardiovascular Disease, Ketone, Gluconeogenesis
3 Jul 2018
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Part 3
You are in correspondence with an ecologist who asserts that the goal of animal foraging
is to maximize energy intake. Using examples, write a response to convince them that animal do
not regard all calories as equal, but regulate the balance of macronutrients.
Lab studies of cockroaches and locusts, and wild non-human primate studies of Borneo
orangutans and Chacma baboons, show strong target selection. This means that animal foraging
aims to regulate the balance of macronutrients when such targets can be reached. Thus, when
resources are available, animals do not regard all calories as equal, but regulate the balance of
macronutrients. It is only when such targets cannot be met that some species may aim to maximize
their energy intake, however this shows that it isn’t the goal of animal foraging to maximize energy
intake.
In a lab study of cockroaches, they were fed a diet of either high protein, low protein and
intermediate protein. They were then allowed free choice. The intake of the cockroaches was
determined and showed that all food groups converged to the same point, showing that they have
an intake target and balance their nutrition to get to this point. Similarly, a lab study of the migratory
locust used different dilutions of protein foods, followed by free choice, to show that they eat to a
nutrient balance. Thus, once again, the locusts have an intake target and balance their nutrition to
get to this point.
In wild non-human primate studies, Borneo orangutans eat fruit and leaves. They aim to
reach an intake target. However, the male intake target has a greater protein composition than the
female composition, due to the need for protein in their larger muscle mass. Pregnant females
sometimes don’t reach the target for the day, however they can compensate for this by overeating
the following day. Similarly, in a long and detailed study of an individual Chacma baboon, it is
possible to deduce that they select an intake target and aim to consume a combination of foods to
reach this target.
Thus, the aim of animal foraging is to regulate the balance of macronutrients. It is only when
resources are limited or these targets are not met, that individuals may use rules of compromise and
maximize their energy intake.
Rules of compromise:
Lab studies
Migratory locust: Seen as a specialist feeder. Will eat to ensure that the excess < deficit.
Desert locust: Seen as a generalist feeder. Will eat to ensure that excess = deficit.
Hybrid Migratory and Desert locust: Shows an intermediate result, combining the specialist and
generalist feeding behaviours.
Gregarious Desert locust: Generalist feeder. They are able to developmentally adapt to the
regulator pattern of their environment.
Solitary Desert locust: Specialist feeder. They are able to developmentally adapt to the regulator
pattern of their environment.
Wild non-human primate studies
Rhesus macaque: This recent study shows that this species eats to maintain maximum energy
intake. They do this by overeating the difference in protein or carbs. When lactating, females will eat
more so the total energy line is raised.
Sifaka lemur: This study explores fragmented and intact forests, at high and low seasons, to show
that they use complementary feeding on fruits and leaves to get as close as they can the target
intake. They eat as much of the fruit that is available, before moving onto leaves. If fruit is scarse
they will eat less overall, in order to stay as close to the target intake rail as possible.
Mountain Gorilla: An African study is used to show that they prioritize non-protein macronutrients
by over eating protein energy. They will eat fruit and leaves when fruit is available, however when
no fruit is available they will eat leaves.
Borneo orangutan: An Indonesian study shows that they prioritize protein intake. At high, low and
intermediate fruit availability the orangutans strongly prioritize their protein intake by under eating
or over eating carbohydrates.
Spider monkey: Strongly prioritize protein intake by over earing or under eating carbohydrates.
Document Summary
You are in correspondence with an ecologist who asserts that the goal of animal foraging is to maximize energy intake. Using examples, write a response to convince them that animal do not regard all calories as equal, but regulate the balance of macronutrients. Lab studies of cockroaches and locusts, and wild non-human primate studies of borneo orangutans and chacma baboons, show strong target selection. This means that animal foraging aims to regulate the balance of macronutrients when such targets can be reached. Thus, when resources are available, animals do not regard all calories as equal, but regulate the balance of macronutrients. It is only when such targets cannot be met that some species may aim to maximize their energy intake, however this shows that it is(cid:374)(cid:859)t the goal of animal foraging to maximize energy intake. In a lab study of cockroaches, they were fed a diet of either high protein, low protein and intermediate protein.
