A Case of Ocular Syphilis in an HIV-Positive Patient With Penicillin Allergy.

Ocular syphilis has a wide range of presentations; however, the most common findings are ophthalmalgia, blurry vision, and erythematous conjunctiva. This report presents a case of ocular syphilis in a human immunodeficiency virus-positive patient with an allergy to penicillin. On presentation, the patient was diagnosed using a fluorescent treponemal antibody absorption test, in addition to rapid plasma reagin. In this case, the patient received alternative treatment with doxycycline prior to penicillin desensitization, with marked improvement of his symptoms.

Aggression Is Induced by Resource Limitation in the Monarch Caterpillar.

Food represents a limiting resource for the growth and developmental progression of many animal species. As a consequence, competition over food, space, or other resources can trigger territoriality and aggressive behavior. In the monarch butterfly, Danaus plexippus, caterpillars feed predominantly on milkweed, raising the possibility that access to milkweed is critical for growth and survival. Here, we characterize the role of food availability on aggression in monarch caterpillars and find that monarch caterpillars display stereotyped aggressive lunges that increase during development, peaking during the fourth and fifth instar stages. The number of lunges toward a conspecific caterpillar was significantly increased under conditions of low food availability, suggesting resource defense may trigger aggression. These findings establish monarch caterpillars as a model for investigating interactions between resource availability and aggressive behavior under ecologically relevant conditions and set the stage for future investigations into the neuroethology of aggression in this system.