Understanding speciation relies critically on the identification of mechanisms responsible for maintaining species integrity (i.e., reproductive isolation) especially when closely related species are sympatric in nature. Studies of reproductive isolation in Drosophila often involve laboratory mating experiments that assume that patterns of mate choice in the laboratory are similar to those in t...

The abnormal abdomen (aa) syndrome in Drosophila mercatorum depends on the presence of R1 inserts in a third or more of the X-linked 28S rDNA genes and the absence of selective underreplication of inserted repeats in polytene tissues that is controlled by an X-linked locus (ur) half a map unit from the rDNA complex. This syndrome affects both life history and morphology in the laboratory. Becau...

We prove two generalizations of the matrix-tree theorem. The first one, a result essentially due to Moon for which we provide a new proof, extends the “all minors” matrix-tree theorem to the “massive” case where no condition on row or column sums is imposed. The second generalization, which is new, extends the recently discovered Pfaffian-tree theorem of Masbaum and Vaintrob into a “Hyperpfaffi...

Characterizing traits critical for adaptation to a given environment is an important first step in understanding how phenotypes evolve. How animals adapt to the extreme heat and aridity commonplace to deserts is an exceptionally interesting example of these processes, and has been the focus of study for decades. In contrast to those studies, where experiments are conducted on either wild animal...