Complementary sex determination, inbreeding depression and inbreeding avoidance in a gregarious sawfly.

Although most Hymenoptera reproduce via arrhenotokous haplodiploidy, the underlying genetic mechanisms vary. Of these, the most widespread mechanism appears to be single-locus complementary sex determination (sl-CSD), in which individuals that are diploid and heterozygous at a sex-determining locus are female, and individuals that are homozygous or hemizygous are male. Because inbreeding increases the probability of producing diploid males, which are often sterile or inviable, sl-CSD can generate substantial inbreeding depression. To counteract this, Hymenoptera with traits that promote inbreeding, such as gregariousness, may evolve one or more of the following: inbreeding avoidance, functional diploid males or alternative sex determination mechanisms. Here, we investigate sex determination, inbreeding depression and inbreeding avoidance in Neodiprion lecontei, a gregarious, pine-feeding sawfly in the family Diprionidae. First, via inbreeding experiments and flow cytometry, we demonstrate that this species has CSD. By modeling expected sex ratios under different conditions, we also show that our data are consistent with sl-CSD. Second, via tracking survival in inbred and outbred families, we demonstrate that inbred families have reduced larval survival and that this mortality is partly attributable to the death of diploid males. Third, using a no-choice mating assay, we demonstrate that females are less willing to mate with siblings than nonsiblings. Together, these results suggest that inbreeding depression stemming from CSD has shaped mating behavior in N. lecontei. These results also set the stage for future comparative work that will investigate the interplay between sex determination, ecology and behavior in additional diprionid species that vary in larval gregariousness.

Frey's syndrome.

Frey's syndrome is a form of gustatory hyperhidrosis that develops following surgery, trauma, or disease of the parotid gland area. Several theories have been proposed to explain the resulting symptomatology. Treatment often is difficult or ineffective. An unusual case is presented involving a patient with delayed onset of symptoms who responded well to topical application of 20% aluminum chloride in anhydrous ethyl alcohol.

Nevus comedonicus of the palm and wrist. Case report with review of five previously reported cases.

Nevus comedonicus (NC) is an uncommon condition consisting of grouped comedo-like papules. Rarely, NC is associated with other structural abnormalities and diseases. Lesions of the palms or soles are distinctly unusual. Histopathologic findings support the concept of a developmental abnormality of the dermal components of the pilosebaceous apparatus with subsequent imperfect differentiation of the epidermal components. Therapy is often unrewarding, although topical tretinoin may be of value.

GC-MS measurement of deuterium in succinic anhydride and TMS-succinate. An isotope memory effect with succinic anhydride.

Direct GC-MS of succinic and glutaric anhydrides has been investigated, and shown to be feasible. In the GC-MS determination of deuterium in succinic anhydride, an isotope memory effect was observed, shown to be due to strong adsorption of solute onto the column. This phenomenon was investigated, together with possible methods for its suppression. Succinate TMS ester also was found to be a suitable derivative for direct GC-MS of deutero-succinic acid.