Master's Theses

Date of Award

2018

Document Type

Thesis

Department

Biology

First Advisor

Amy Berkov

Second Advisor

David Lohman

Third Advisor

Ana Carnaval

Keywords

longhorn beetles, ecology, dry season, wood traits, early colonists, insect-plant interactions

Abstract

Tree life history strategies are correlated with functional plant traits, such as wood density (WD), moisture content (MC), bark thickness (BT), and nitrogen content (N); these traits affect the nutrients available to xylophagous insects. Cerambycid beetles feed on substrates that vary in these traits, but little is known about how they affect community composition. The goal of this project is to document the abundance of two cerambycid subfamilies (Cerambycinae and Lamiinae) and the WD, MC, BT, and N content in the wood they eat. In a salvage project conducted adjacent to the Panama Canal, trees were felled and exposed to Cerambycidae for oviposition. Disks from branches of differing thickness from the same plant individuals were used to calculate WD, MC, and BT in the field; nitrogen content was determined using mass spectrometry. Thick and thin branches tended to differ in wood trait values; therefore, data were analyzed separately in subsequent analyses. In thin branches, cerambycid abundance and species richness were higher in samples with less dense, moister wood, and thicker bark. Thick branches showed similar trends, but the wood traits accounted for little variability in beetle abundance or species richness. There were no significant correlations between beetle data and nitrogen. Cerambycines emerged more slowly, and from denser, drier wood, than lamiines. Cerambycines might be more drought-tolerant than lamiines, and therefore more resistant to the longer, more severe dry seasons that are predicted to occur due to climate change.

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