Question

Mexican colonial web building spiders nest in colonies that range in size from 10 to thousands of individuals, with each individual occupying their own web within the colony. Colonies are frequently attacked by predatory wasps. Individuals in larger colonies suffer lower predation than those in smaller colonies. The data in the graph above are from a study performed by Uetz et al. (2002), where they measure the distance at which spiders responded to potential predators. Open bars are for spiders on the interior and colored bars are for spiders on the periphery of the colony. What type of grouping benefit is demonstrated here?

dilution
group defense
increased vigilance
cooperative foraging

Answer 1

Option 2). The type of grouping benefit demonstrated here is group defense. Individuals in larger colonies of Mexican colonial web building spiders have increased vigilance and respond to potential predators from a greater distance compared to individuals in smaller colonies.

Step-by-step explanation:

This example of a grouping benefit is group defense. According to the graph, individuals in larger colonies—both inside and outside—respond to possible predators by moving farther away than individuals in smaller colonies. The colony as a whole is better shielded from predator attacks thanks to this heightened awareness and reaction. Hence, Option 2) is the correct answer.