Great ranging associated with greater reproductive investment in mammals

Abstract

Most animals must travel to find food, incurring an unavoidable energy and time cost. Economic theory predicts, and experimental work confirms, that within species, increasing the distance traveled each day to find food has negative fitness consequences, decreasing the amount of energy invested in maintenance, repair, and reproduction. Here, we show that this relationship between daily distance traveled and reproductive success is fundamentally different between species and over evolutionary time in many lineages. Phylogenetically controlled analyses of 161 eutherian mammals indicate that, after controlling for body mass, evolutionary increases in the daily distance traveled are associated with corresponding increases in both total fertility (number of offspring per lifetime) and total offspring mass (grams of offspring per lifetime). This suggests that over evolutionary time, increasing travel distance is often part of a strategy for procuring more food energy and not necessarily a response to decreased food availability. These results have important implications for ecological comparisons among species, including assessments of habitat quality based on locomotor behavior.ecology ͉ energetics ͉ reproduction ͉ life history ͉ foraging economics H ow far will an animal travel each day? A broad range of ecological pressures influence ranging decisions (1-7), making this seemingly straightforward question exceedingly difficult to answer definitively. In the simplest case, in which an animal requiring a net energy intake of E net (J/day) acquires food energy at a constant rate B (J/m) and spends energy on travel at some rate C (J/m), it must travel sufficient distance, D (m/day), so thatPerhaps surprisingly, despite considerable variation and complexity in foraging and ranging behaviors, this simple relationship between daily movement distance, food availability, and energy requirements is generally supported by behavioral observation in a broad range of species. While ecological constraints cannot always be linked to foraging behavior (7) and physiological constraints may limit ranging ability (8), large interspecific comparisons of foraging behavior indicate that daily movement distance, D, is primarily determined by the need to acquire sufficient food energy (2, 3, 6). For example, daily movement distance increases with body size and diet quality, reflecting both size-related increases energy requirements and the relative scarcity of high-quality, energy-dense foods on the landscape (2, 6). Further, decreases in an individual's rate of food acquisition, B, whether through experimental manipulation in the laboratory (9-14), increased foraging group size (1, 4, 6, 15) or through seasonal changes in food availability in the wild (16-19) typically leads to increases in the daily distance traveled.In principle, one might expect longer daily movement distances to be energetically beneficial, since greater D will lead to greater E net as long as B Ͼ C (10, 20). In practice, however, while some species may increase foragi...

Metabolic adaptation for low energy throughput in orangutans

“…An accelerated metabolic rate in the hominin lineage would be consistent with humans' high rate of reproduction (7) and large brains (9,11) relative to other apes. If increased throughput is linked to decreased variance in food availability as proposed previously (4,6), the adoption of provisioning behaviors may ultimately explain why human reproductive rates diverged from those of other hominoids. Direct measures of daily energy use in other apes, as well as human foragers, are needed to test these evolutionary hypotheses.…”

“…Both within (2) and among (3) species, increased energy throughput (i.e., calories consumed and expended per day) is associated with increased reproductive output (i.e., grams of offspring produced per year). In habitats in which food resources are abundant, organisms may benefit from adopting higher energy throughput, increasing their food requirements but providing more energy for reproduction (4)(5)(6). Conversely, if food availability is highly variable or if foraging incurs the risk of predation, it may be advantageous to decrease DEE, even at the cost of decreased reproductive rates, to avoid starvation or predation (5,6).…”

“…In habitats in which food resources are abundant, organisms may benefit from adopting higher energy throughput, increasing their food requirements but providing more energy for reproduction (4)(5)(6). Conversely, if food availability is highly variable or if foraging incurs the risk of predation, it may be advantageous to decrease DEE, even at the cost of decreased reproductive rates, to avoid starvation or predation (5,6). Indeed, several comparative studies have suggested a continuum of energyuse strategies among mammals, from high-energy throughput to low, with each species' strategy contingent upon the particular dynamics of food availability and mortality risk it faces (1,(4)(5)(6).…”

Pliocene hominin biogeography and ecology

“…Similarly, calculating the energetic requirements of a hominin continues to be a subject of debate (Steudel-Numbers, 2006;Pontzer, 2012b). As a simplification, it is considered appropriate here to assume the daily energy expenditure (DEE) to fall between 2 and 4 times the BMR (Pontzer and Kamilar, 2009), where BMR ¼ 354 W 0.75 per day (Altmann, 1998).…”

KELIMPAHAN DAN SEBARAN POPULASI PESUT MAHAKAM (Orcaella brevirostris Gray, 1866) DI SUNGAI MAHAKAM KALIMANTAN TIMUR

“…Wujud dari upaya tersebut adalah berjalan/bergerak lebih jauh untuk mencari dan mendapatkan makanan (Chapman & Teichroeb, 2012). Persaingan juga menyebabkan laju perolehan pakan individu menurun sehingga hal itu berdampak pada peningkatan jarak jelajah harian (Pontzer & Kamilar, 2009). Teori itu bersesuaian dengan fakta yang ada sekarang (Tabel 2).…”