Presentation Title

Influence of density-dependent competition on the feeding behavior of burying beetles Nicrophorus marginatus

Advisor Information

Claudia Rauter

Location

Milo Bail Student Center Council Room

Presentation Type

Oral Presentation

Start Date

8-3-2013 2:15 PM

End Date

8-3-2013 2:30 PM

Abstract

At high population densities with intense competition for food has a strong impact on feeding behaviors. It has been observed in herbivorous, gregarious insect larvae and social vertebrates that there is a strong selection for increased feeding rates, at the cost of reduced efficiency in energy uptake when a single individual cannot monopolize the food source. The goal of this study was to examine the effect of density-dependent competition on feeding behavior and mass change in adult burying beetles Nicrophorus marginatus that feed on carrion. Newly emerged beetles were assigned at random to one of three density treatments: i) 1 male and 1 female, ii) 2 males and 2 females, and iii) 3 males and 3 females. Over 5-weeks, each group of beetles was observed once a week for 1 hour while feeding on an artificial food source. For all density treatments, time spent feeding and mass gain during feeding was highest in week 1 and decreased afterwards continuously. The loss of mass between feedings was largest between week 1 and 2 and decreased over the following weeks. In week 1, time spent feeding and mass gain increased with density, while loss of mass between week 1 and 2 decreased with increasing density. The differences between density treatments diminished with increasing duration of the experiment. These results suggest that beetles show the same behavior as herbivorous, gregarious insect larvae and social vertebrates; only at the beginning of the experiment. The disappearance of the density effect suggests habituation to stressful conditions.

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Mar 8th, 2:15 PM Mar 8th, 2:30 PM

Influence of density-dependent competition on the feeding behavior of burying beetles Nicrophorus marginatus

Milo Bail Student Center Council Room

At high population densities with intense competition for food has a strong impact on feeding behaviors. It has been observed in herbivorous, gregarious insect larvae and social vertebrates that there is a strong selection for increased feeding rates, at the cost of reduced efficiency in energy uptake when a single individual cannot monopolize the food source. The goal of this study was to examine the effect of density-dependent competition on feeding behavior and mass change in adult burying beetles Nicrophorus marginatus that feed on carrion. Newly emerged beetles were assigned at random to one of three density treatments: i) 1 male and 1 female, ii) 2 males and 2 females, and iii) 3 males and 3 females. Over 5-weeks, each group of beetles was observed once a week for 1 hour while feeding on an artificial food source. For all density treatments, time spent feeding and mass gain during feeding was highest in week 1 and decreased afterwards continuously. The loss of mass between feedings was largest between week 1 and 2 and decreased over the following weeks. In week 1, time spent feeding and mass gain increased with density, while loss of mass between week 1 and 2 decreased with increasing density. The differences between density treatments diminished with increasing duration of the experiment. These results suggest that beetles show the same behavior as herbivorous, gregarious insect larvae and social vertebrates; only at the beginning of the experiment. The disappearance of the density effect suggests habituation to stressful conditions.