The group-size paradox: effects of learning and patch departure rules

Guy Beauchamp; Esteban Fernández-Juricic
March 2005
Behavioral Ecology;Mar2005, Vol. 16 Issue 2, p352
Academic Journal
In many species, foraging in groups can enhance individual fitness. However, groups are often predicted to be larger than the size that maximizes individual fitness. This is because individual foragers are expected to continue joining a group until the fitness in the group falls to the level experienced by solitary foragers. If such a process were pervasive, social foraging, paradoxically, would provide little evolutionary advantages. We propose a solution to the group-size paradox by allowing foragers to learn about habitat quality and leave food patches when their current intake rate falls below that expected for the whole habitat. By using a simulation model, we show that under a wide range of population sizes, foragers using such rules abandon under- and overcrowded patches, ensuring that group size remains close to the optimal value. The results hold in habitats with varying patch quality, but we note that the lack of food renewal in patches can disrupt the process of group formation. We conclude that groups of optimal sizes can occur frequently if fitness functions are peaked and resources patchily distributed, without the need to invoke relatedness between joiners and established group members, group defense against joiners, or other mechanisms that were proposed earlier to prevent groups from becoming too large.


Related Articles

  • OLD WORLD MONKEYS.  // Zoobooks;Apr2010, Vol. 27 Issue 6, p1 

    The article offers information on Old World monkeys. Similarities between monkeys and people include emotions, anatomy and movements. The total number of monkey species is 200. Both Old World and New World monkeys live in rain forests, grasslands and open savannas. One can distinguish Old and...

  • Settlement patterns, foraging behavior, and reproductive success of ospreys along a heterogeneous riverine corridor. Harmata, Peter J.; Restani, Marco; Harmata, Alan R. // Canadian Journal of Zoology;Jan2007, Vol. 85 Issue 1, p56 

    In 1998 and 1999, we determined the spatial distribution, foraging behavior, and reproductive success of ospreys (Pandion haliaetus (L., 1758)) nesting along the upper Missouri River, Montana. We combined our data with that collected in the same area in 1981–1982 and 1990–1991 to...

  • STAYING ALIVE AND FITTING IN.  // Amazing Mammals: Part I;2005, p35 

    This article offers a look at the foods different mammals eat, how mammals defend themselves and the ways mammals fit into their habitats. The way mammals, and all other animals, live has a lot to do with the kind of food they eat. Kangaroos and bison are examples of herbivores or animals that...

  • Presence of the Mediterranean Monk Seal (Monachus monachus) in the Croatian Part of the Adriatic Sea. Gomerčić, Tomislav; Huber, Đuro; Gomerčić, Martina Đuras; Gomerčić, Hrvoje // Aquatic Mammals;Sep2011, Vol. 37 Issue 3, p243 

    The article presents a study on the survival of Mediterranean Monk Seal in the Croatian Part of the Adriatic Sea. It provides description of the monk seal's behavior and physical appearance. It suggests on the protection of selected microlocalities of repeated sightings to aid the full return of...

  • Ontogenetic development during changeover from an endogenous to exogenous nutritional source in Laotian cyprinid Cirrhinus microlepis larvae. Morioka, Shinsuke; Cacot, Philippe; Moteki, Masato; Thipvantong, Vilakone; Philavong, Somphanh; Pounvisouk, Latsamy; Chantasone, Phonaphet; Thaphysy, Vienvily // Fisheries Science;Mar2012, Vol. 78 Issue 2, p221 

    The nutritional transition process from endogenous to exogenous feeding in larvae of the Laotian indigenous cyprinid Cirrhinus microlepis was investigated approximately 200 h after hatching. Although 17 characters were observed, emphasis was given to those associated with the onset of feeding...

  • As big as they get. Milewski, Antoni V. // Wildlife Australia;Winter2006, Vol. 43 Issue 2, p16 

    The article focuses on the effect of category 5 Cyclone Larry on the habitat of tree-living species in Australia. The cyclone, which hit the region on March 20, 2006, has damaged the trees, snapped off tree tops and has made large trees fall down. Animals such as the rainforest ringtail possum...

  • How Do Planktonic Larvae Know Where to Settle? Morse, Aileen N.C. // American Scientist;Mar/Apr91, Vol. 79 Issue 2, p154 

    Investigates into the survival behavior of planktonic larvae, such as the red abalone. Description and characteristics; Response to inducer molecules; Other marine invertebrates wherein the lessons learned from the red abalone can be applied.

  • Territoriality and survivorship of the Sierra Madre sparrow in La Cima, México. Oliveras de Ita, Adán; Gómez de Silva, H´ctor // Biodiversity & Conservation;Apr2007, Vol. 16 Issue 4, p1055 

    We studied the life-history of the Sierra Madre sparrow (Xenospiza baileyi) in a subalpine grassland-agriculture mosaic south of Mexico City. From March to early September 1999 we captured and color-banded 53 adults with mistnets and mapped the breeding territories of 21 males. We again mapped...

  • Use of multi-state models to explore relationships between changes in body condition, habitat and survival of grizzly bears Ursus arctos horribilis. Boulanger, John; Cattet, Marc; Nielsen, Scott E.; Stenhouse, Gord; Cranston, Jerome // Wildlife Biology;Sep2013, Vol. 19 Issue 3, p274 

    One of the principal goals of wildlife research and management is to understand and predict relationships between habitat quality, health of individuals and their ability to survive. Infrequent sampling, non-random loss of individuals due to mortality and variation in capture susceptibility...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics