Tolerance for nutrient imbalance in an intermittently feeding herbivorous cricket, the Wellington tree weta

PLoS One. 2013 Dec 17;8(12):e84641. doi: 10.1371/journal.pone.0084641. eCollection 2013.

Abstract

Organisms that regulate nutrient intake have an advantage over those that do not, given that the nutrient composition of any one resource rarely matches optimal nutrient requirements. We used nutritional geometry to model protein and carbohydrate intake and identify an intake target for a sexually dimorphic species, the Wellington tree weta (Hemideina crassidens). Despite pronounced sexual dimorphism in this large generalist herbivorous insect, intake targets did not differ by sex. In a series of laboratory experiments, we then investigated whether tree weta demonstrate compensatory responses for enforced periods of imbalanced nutrient intake. Weta pre-fed high or low carbohydrate: protein diets showed large variation in compensatory nutrient intake over short (<48 h) time periods when provided with a choice. Individuals did not strongly defend nutrient targets, although there was some evidence for weak regulation. Many weta tended to select high and low protein foods in a ratio similar to their previously identified nutrient optimum. These results suggest that weta have a wide tolerance to nutritional imbalance, and that the time scale of weta nutrient balancing could lie outside of the short time span tested here. A wide tolerance to imbalance is consistent with the intermittent feeding displayed in the wild by weta and may be important in understanding weta foraging patterns in New Zealand forests.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Energy Intake
  • Female
  • Gryllidae*
  • Herbivory*
  • Male
  • New Zealand
  • Trees*

Grants and funding

PMW was supported by FRST postdoctoral fellowship MAUX0905. MMR had Massey University Research Funding MURF_11/0039. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.