Abstracts (first author)
Transcriptomics of a life history trade-off in the wing polymorphic cricket (Gryllus firmus)
The sand cricket Gryllus firmus is a model species in the study of the trade-off between (flight) dispersal and fecundity associated with wing-polymorphism in insects. G. firmus females exist as either a flight capable, long-winged (LW(f)) morph that delays egg production or as a flight-incapable, short-winged (SW) morph with substantially elevated egg production. In addition, some adult LW(f) individuals partially degenerate their flight musculature, thus giving rise to a third morph (LW(h)), that exhibits the substantially increased egg production seen in the SW morph. Here we present findings of a transcriptomics study that examined molecular mechanisms underlying plasticity in flight muscle and fat body function among the G. firmus morphs. Expression of genes encoding proteasome components was significantly enhanced in LW(h) flight muscle, however we observed a striking, nearly complete absence of differences in flight muscle sarcomere gene expression between LW(f) and LW(h) morphs. This indicates that flight muscle histolysis in the LW(h) morph is a highly controlled and selective process, and that maintenance of non-histolyzed fibers in LW(h) flight muscle is controlled through gene expression patterns similar to that in the LW(f) morph. In addition, LW(h) morph flight muscle displayed a significant reduction in expression of genes encoding aspects of mitochondrial structure and metabolism, supportive of earlier enzymological and metabolic rate work in this species. Genes involved in triglyceride biosynthesis were significantly upregulated in LW(f) fat body tissue, while SW fat body exhibited substantially elevated expression of an insulin-like peptide known to regulated egg production in locusts, as well as a number of lectin-related proteins that function in immunity. We will discuss our findings with respect to the physiological and molecular mechanisms underlying the flight-fecundity trade-off in G. firmus and other insect species.