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Pleiotropy (multiple phenotypic effects of single genes) and epistasis (gene interaction) play key roles in the development of complex phenotypes and might be especially important in polymorphic taxa. The development of discrete and heritable sympatric phenotypic polymorphisms often emerges from major-effect genes that interact with other loci and have pleiotropic effects on multiple traits and physiological functions. We quantified gene expression changes during ontogenetic colour development in an insect (damselfly: Ischnura elegans ) with three heritable female colour morphs, one which is a male mimic. Using transcriptome sequencing and de novo assembly, we demonstrate that all morphs show extensive downregulation of gene expression during early colour development. Morphs then become increasingly differentiated during sexual maturation and when developing adult colouration. These different ontogenetic trajectories arise because of the heterochronic development of the male-mimicking females, compared to other two female morphs. Many loci with regulatory functions in reproductive development are uniquely regulated in male-mimicking females, including upstream and downstream regulators of ecdysone signalling and transcription factors that influence insect sexual differentiation. Our study reveals extensive epistasis in the genomic architecture of I. elegans and suggest a central role for pleiotropy in shaping the developmental trajectories of the different morphs.

A subsample of 332, 0.06-hectare plots measured during 2001–2002 in Houston, TX, U.S., were relocated and measured in 2008 following Hurricane Ike. These 37 re-measured plots provide a unique opportunity to explore the effects of urbanization and hurricanes on the forest structure of coastal urban forests. Statistical analyses of growth, mortality, and in-growth were conducted using plot- and tree-level factors. In total, 305 trees were re-measured, of which 195 (63.9%) still remained on-site and 110 (36.1%) had been removed. Ninety-seven (31.8%) of these trees were determined to be removed due to urbanization and 13 trees (4.3%) were removed due to hurricane impacts. Results show an overall annual net loss in tree numbers and an increase in tree density during the analysis period. Average annual mortality and in-growth rates were 3.9% and 5.3%, respectively. Growth rates were significantly influenced by land cover type, tree stem diameter, crown width, and percent dieback (P < 0.05). Overall, Hurricane Ike resulted in the removal of 4.3% of all trees measured, with removal occurring on six (16%) of the 37 re-measured plots. These initial findings could be used to understand changes in forest structure in coastal urban areas, improve estimates of carbon sequestration, and develop management goals.