Date of Award

Fall 12-2018

Degree Type


Degree Name


Degree Program

Biological Sciences


Biological Sciences

Major Professor

Howard, Jerome

Second Advisor

Lailvaux, Simon

Third Advisor

Atallah, Joel


Phenotypic plasticity is favored in heterogeneous environments in which alternative phenotypes can exploit alternative resources. However, it’s not clear whether phenotypic plasticity is useful in environments that become more homogenous over an organism’s life cycle. I studied a population of grasshopper Melanoplus differentialis that experiences high resource diversity as nymphs but low resource diversity as adults to determine if individuals can undergo diet-induced morphological plasticity in head shape to increase biting ability and ingestion of hard diets. Insects on a soft diet were larger and had greater bite force than those on a hard diet. Head structures related to chewing ability changed shape with mass, heads became taller and narrower. Scaling relationships among body parts suggested that there wasn’t evidence for tradeoff in allocation to chewing vs. locomotor performance. Results are consistent with the idea that essential adult feeding morphology constrains the advantage of plasticity in feeding structures among nymphs.


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