Detection of seed DNA in regurgitates of granivorous carabid beetles.

Granivory can play a pivotal role in influencing regeneration, colonization as well as abundance and distribution of plants. Due to their high abundance, nutrient content and longevity, seeds are an important food source for many animals. Among insects, carabid beetles consume substantial numbers of seeds and are thought to be responsible for a significant amount of seed loss. However, the processes that govern which seeds are eaten and are therefore prevented from entering the seedbank are poorly understood. Here, we assess if DNA-based diet analysis allows tracking the consumption of seeds by carabids. Adult individuals of Harpalus rufipes were fed with seeds of Taraxacum officinale and Lolium perenne allowing them to digest for up to 3 days. Regurgitates were tested for the DNA of ingested seeds at eight different time points post-feeding using general and species-specific plant primers. The detection of seed DNA decreased with digestion time for both seed species, albeit in a species-specific manner. Significant differences in overall DNA detection rates were found with the general plant primers but not with the species-specific primers. This can have implications for the interpretation of trophic data derived from next-generation sequencing, which is based on the application of general primers. Our findings demonstrate that seed predation by carabids can be tracked, molecularly, on a species-specific level, providing a new way to unravel the mechanisms underlying in-field diet choice in granivores.

Stable isotope analysis reveals whether soil-living elaterid larvae move between agricultural crops.

Tracking the movement of soil-living herbivores is difficult, albeit important for understanding their spatial ecology as well as for pest management. In this study the movement of Agriotes obscurus larvae between plots harbouring isotopically different plants was examined. Neither between maize and wheat nor between maize and grassland movement could be detected. These data suggest that Agriotes larvae rarely disperse between crops as long as local food supply is sufficient. Moreover, the current approach provides a new means to study the dispersal of soil invertebrates in situ.

Learning to live with controlled ventricular tachycardia: utilizing the Johnson model.

In view of the multifaceted needs of both patients and families, the role of the nurse lies in assessing system instability and in prioritizing efforts for stabilization within the hospital. Since the problems are so complex, it may be impossible to resolve all of them before discharge. Therefore, follow-up referrals to counseling services and visiting nurse associations are helpful. Of added benefit is an ongoing, supportive relationship with a physician and/or a nurse specialist who is familiar with the needs of these special patients and their families. The use of a behavioral systems model such as Johnson's assists the nurse in organizing assessments of patient and family needs and in planning nursing strategies to meet those needs. The patient's very realistic fears of dying coupled with the frequently occurring loss of cardiac function present an enormous challenge to the nurses who work with them. The close professional relationships that result from this process are extremely rewarding.