Defining the Insect Pollinator Community Found in Iowa Corn and Soybean Fields: Implications for Pollinator Conservation.

Although corn (Zea mays L.) and soybeans (Glycine max L.) do not require pollination, they offer floral resources used by insect pollinators. We asked if a similar community of insect pollinators visits these crops in central Iowa, a landscape dominated by corn and soybean production. We used modified pan traps (i.e., bee bowls) in both corn and soybean fields during anthesis and used nonmetric multidimensional scaling (NMS) to compare the communities found in the two crops. Summed across both crops, 6,704 individual insects were captured representing at least 60 species, morphospecies, or higher-level taxa. Thirty-four species were collected in both crops, 19 collected only in corn and seven were collected only in soybean. The most abundant taxa were Lasioglossum [Dialictus] spp., Agapostemon virescens Cresson, Melissodes bimaculata (Lepeletier), and Toxomerus marginatus (Say), which accounted for 65% of the insect pollinators collected from both crops. Although social bees (Apis mellifera L. and Bombus spp.) were found in both crops, they accounted for only 0.5% of all insects captured. The NMS analysis revealed a shared community of pollinators composed of mostly solitary, ground nesting bees. Many of these species have been found in other crop fields throughout North America. Although corn and soybean are grown in landscapes that are often highly disturbed, these data suggest that a community of pollinators can persist within them. We suggest approaches to conserving this community based on partnering with activities that aim to lessen the environmental impact of annual crop production.

Monotherapy with piperacillin/tazobactam versus combination therapy with ceftazidime plus amikacin as an empiric therapy for fever in neutropenic cancer patients.

Between July 1993 and September 1996, 107 consecutive febrile episodes in 83 neutropenic cancer patients with a median age of 41 years were randomized to treatment either with piperacillin/tazobactam 4.5 g every 8 h i.v. or ceftazidime 2 g every 8 h plus amikacin 15 mg/kg i.v. per day. In the case of fever > 38 degrees C 48 h after initiation of the antibiotic therapy, vancomycin 500 mg every 6 h i.v. was added. The study population was at serious risk of a poor outcome, since 67% of the patients had leukemia or lymphoma, 19% of the febrile events occurred after autologous bone marrow or blood stem cell transplantation, the median total duration of neutropenia was 16 days, and the median neutrophil count at study inclusion was 0.09 x 10(9)/1. The two patient groups were comparable in terms of risk factors. Bacteremia was found in 37%, other microscopically documented infections in 16%, and clinically documented infections in 26% of the febrile episodes. Most (96) febrile episodes were evaluable for response. No significant difference was found between piperacillin/ tazobactam and ceftazidime plus amikacin in terms of success rate (81% versus 83%), empirical addition of vancomycin (42% versus 38%), median time to fever defervescence (3.3 versus 2.9 days) or median duration of antibiotic therapy (7.2 versus 7.4 days). No patient died from the infection. Both antibiotic regimens were well tolerated, the study treatment being stopped only in 1 patient because of toxicity (cutaneous allergy to piperacillin/tazobactam). On the basis of the 107 febrile events encountered, we conclude that piperacillin/tazobactam is a safe and effective monotherapy. To define the definitive value of piperacillin/ tazobactam as a monotherapy for febrile neutropenic patients a large randomized trial is warranted.