Dissertation

Innate immunity, developmental speed and their trade-offs in two hexapod models

This thesis focuses on important life history traits and their trade-offs using two hexapod models. Particularly, the trade-off between immune defense and embryonic developmental speed is a central theme of this study.

Author: S. Cheng
Date: 28 November 2023
Links: Thesis in Leiden Repository

In short, I study the details of immune defenses during embryonic development of basal hexapods in Chapter 2, the trade-off with developmental speed in Chapter 3, and the genetic basis of developmental speed in Chapter 4, using selection lines of the red flour beetle Tribolium castaneum.
I demonstrate that 1) springtail eggs do show an immune response, despite absence of a serosa that provides immune protection to insect eggs; 2) a strong trade-off is present between developmental speed and fecundity in the selection lines of the beetle T. castaneum; and 3) a life-history allele of large effect shortens developmental time in this wild insect population. I suggest that such alleles of large effect play a crucial role when insects have to adapt their developmental speed to current climate change.