A small survey of introduced Zaprionus indianus (Diptera: Drosophilidae) in orchards of the eastern United States.

The African fig fly, Zaprionus indianus (Gupta), is a generalist fruit fly that typically breeds in decaying fruits from over 70 plant species. The species has spread globally from its native range in tropical Africa, becoming an invasive pest on ripening figs in Brazil. First reported in the United States in 2005 in Florida, Z. indianus has since been documented as far north as Canada and is hypothesized to recolonize northwards from southern refugia each year. We sampled drosophilid communities over the growing season at 2 orchards in Virginia from 2020 to 2022 and 11 orchards along the East Coast during the fall of 2022 to quantify the abundance of Z. indianus relative to other drosophilids across locations, seasons, and fruit crops. Massachusetts had the northernmost population, with no Z. indianus detected in Maine and no correlation between latitude and relative abundance. Variation in Z. indianus relative abundance was high between nearby orchards and abundance was higher on peaches relative to apples within orchards. Comparisons of seasonal abundance curves between 2 Virginia orchards showed similar dynamics across years with individuals first detected around July and becoming absent around December, with peaks in late summer and mid-fall. The variation in seasonal and latitudinal abundance shown here highlights a need for broader sampling to accurately characterize the range, spread, and environmental tolerances of Z. indianus in North America.

Spatial and temporal variation in abundance of introduced African fig fly (Zaprionus indianus) (Diptera: Drosophilidae) in the eastern United States.

The African fig fly, Zaprionus indianus (Gupta), has spread globally from its native range in tropical Africa, becoming an invasive crop pest in select areas such as Brazil. Z. indianus was first reported in the United States in 2005 and has since been documented as far north as Canada. As a tropical species, Z. indianus is expected to have low cold tolerance, likely limiting its ability to persist at northern latitudes. In North America, the geographic regions where Z. indianus can thrive and seasonal fluctuations in its abundance are not well understood. The purpose of this study was to characterize the temporal and spatial variation in Z. indianus abundance to better understand its invasion of the eastern United States. We sampled drosophilid communities over the growing season at two orchards in Virginia from 2020-2022 and several locations along the East Coast during the fall of 2022. Virginia abundance curves showed similar seasonal dynamics across years with individuals first detected around July and becoming absent around December. Massachusetts was the northernmost population and no Z. indianus were detected in Maine. Variation in Z. indianus relative abundance was high between nearby orchards and across different fruits within orchards but was not correlated with latitude. Fitness of wild-caught females decreased later in the season and at higher latitudes. The patterns of Z. indianus abundance shown here demonstrate an apparent susceptibility to cold and highlight a need for systematic sampling to accurately characterize the range and spread of Z. indianus.

A Milk-Fat Based Diet Increases Metastasis in the MMTV-PyMT Mouse Model of Breast Cancer.

A high-fat diet (HFD) and obesity are risk factors for many diseases including breast cancer. This is particularly important with close to 40% of the current adult population being overweight or obese. Previous studies have implicated that Mediterranean diets (MDs) partially protect against breast cancer. However, to date, the links between diet and breast cancer progression are not well defined. Therefore, to begin to define and assess this, we used an isocaloric control diet (CD) and two HFDs enriched with either olive oil (OOBD, high in oleate, and unsaturated fatty acid in MDs) or a milk fat-based diet (MFBD, high in palmitate and myristate, saturated fatty acids in Western diets) in a mammary polyomavirus middle T antigen mouse model (MMTV-PyMT) of breast cancer. Our data demonstrate that neither MFBD or OOBD altered the growth of primary tumors in the MMTV-PyMT mice. The examination of lung metastases revealed that OOBD mice exhibited fewer surface nodules and smaller metastases when compared to MFBD and CD mice. These data suggest that different fatty acids found in different sources of HFDs may alter breast cancer metastasis.