Rosemary Malfi

University of Massachusetts Amherst | UMass Amherst · Department of Biology

Community diversity can reduce the prevalence and spread of disease, but certain species may play a disproportionate role in diluting or amplifying pathogens. Flowers act as both sources of nutrition and sites of pathogen transmission, but the effects of specific plant species in shaping bee disease dynamics are not well understood. We evaluated wh...

Foraging preferences are known to differ among bee taxa, and can also differ between male and female bees of the same species. Similarly, bees can prefer a specific flower sex, particularly if only one sex provides pollen. Such variation in foraging preferences could lead to divergent bee communities visiting different flower sexes of a plant speci...

Landscapes can affect parasite epidemiology in wild and agricultural animals. Honey bees are threatened by loss of floral resources and by parasites, principally the mite Varroa destructor and the viruses it vectors. Existing mite control relies heavily on chemical treatments that can adversely affect bees. Alternative, pesticide-free control metho...

Sustainable agriculture relies on pollinators, and wild bees benefit yield of multiple crops. However, the combined exposure to pesticides and loss of flower resources, driven by agricultural intensification, contribute to declining diversity and abundance of many bee taxa. Flower plantings along the margins of agricultural fields offer diverse foo...

Conditions experienced early in development can affect the future performance of individuals and populations. Demographic theories predict persistent population impacts of past resources, but few studies have experimentally tested such carry‐over effects across generations or cohorts. We used bumble bees to test whether resource timing had persiste...

Anthropogenic landscape changes can affect parasite epidemiology in wild and agricultural animals. Honey bees are agricultural animals whose services are threatened by loss of floral resources and by parasites, most notably the invasive mite Varroa destructor . Existing mite control strategies rely heavily on chemical treatments that can adversely...

• Behavior and organization of social groups is thought to be vital to the functioning of societies, yet the contributions of various roles within social groups toward population growth and dynamics have been difficult to quantify. A common approach to quantifying these role‐based contributions is evaluating the number of individuals conducting cer...

1. Behavior and organization of social groups is thought to be vital to the functioning of societies, yet the contributions of various roles within social groups towards population growth and dynamics have been difficult to quantify. A common approach to quantifying these role-based contributions is evaluating the number of individuals conducting c...

Many pollinator species are declining due to a variety of interacting stressors including pathogens, sparking interest in understanding factors that could mitigate these outcomes. Diet can affect host-pathogen interactions by changing nutritional reserves or providing bioactive secondary chemicals. Recent work found that sunflower pollen (Helianthu...

1. Behavior and organization of social groups is thought to be vital to the functioning of societies, yet the contributions of various roles within social groups have been difficult to quantify. A common approach to quantifying these role-based contributions is evaluating the performance of individuals at conducting certain roles, these studies ign...

The temporal distribution of resources is an important aspect of habitat quality that can substantially impact population success. Although it is widely accepted that floral resources directly influence wild bee population sizes, we lack experimental data evaluating how resource availability affects colony growth via demographic mechanisms. To achi...

Floral resources and natural enemies are considered important drivers of wild bee population dynamics, yet there is little information on how these factors, either independently or in combination, influence the demographic performance of bees. Bumble bees (Bombus spp.), ecologically important social insects, have long colony cycles lasting many wee...

Endoparasitoids develop inside the body of a host organism and, if successful, eventually kill their host in order to reach maturity. Host species can vary in their suitability for a developing endoparasitoid; in particular, the host immune response, which can suppress egg hatching and larval development, has been hypothesized to be one of the most...

Some members of Conopidae and other families of flies require development within hymenopteran hosts. Rearing of parasitized Apoidea provides valuable life history and ecological data but is rarely documented. Greater emphasis on gathering and analyzing rearing data is required. Analysis of a new video record of Physocephala tibialis (Say) reared fr...

Background / Purpose: Parasitoid conopid flies are a common antagonist of bumble bees through much of their geographic range and can infect up to 70% of foragers. While conopids typically kill their host in 10-12 days, they can alter host behavior prior to death, thereby contributing sublethal effects as well as lethal effects to colony dynamics....

Background/Question/Methods Parasitoid conopid flies are a common antagonist of bumble bees through much of their geographic range and can infect up to 70% of foragers. While conopids typically kill their host in 10-12 days, they can alter host behavior prior to death, thereby contributing sublethal effects as well as lethal effects to colony dyna...

Background/Question/Methods Bumblebees (Bombus spp.) are social insects that play a vital role in the pollination of commercial and wild plants worldwide. Bumblebees demand high amounts of pollen and nectar to maintain and grow their colonies, and colony size is closely related to survival and reproduction. Trips to return required food resources...

Alterations of host behaviour in response to parasitism are widely documented. Modified host behaviour is considered an adaptive manipulation when it is induced by and provides a clear benefit to the parasite. Variability in the response of host organisms to parasitic manipulations can result in some hosts being more suitable than others if failure...

In recent decades, several N orth A merican bumble bee ( Bombus spp.) species have undergone precipitous declines. It is suspected that a parasite or pathogen may be responsible, yet few studies have examined the extent of parasitism and the ecology of host–parasite relationships in U.S . bumble bee populations. A season‐long survey of bumble bees...

Background/Question/Methods Many parasites and parasitoids manipulate the behavior of their hosts to maximize their own survival and/or reproductive fitness. Parasitoids are also known to selectively infect their hosts based on certain physical characteristics that optimize the fitness of the parasite or its offspring. Conopid flies (Conopidae) a...

Bumblebees (Bombus spp.) are important pollinators both ecologically and economically. Many bumblebee species have experienced significant declines in both North America and Europe. Habitat loss and fragmentation associated with agricultural intensification are purported causes in several cases. Studies also suggest that reduction of host plant abu...

Background/Question/Methods Within the last two decades, notable shifts have taken place within the bumble bee (Bombus spp.) communities of North America: some species have experienced substantial, rapid declines, while others appear to be stable or even experiencing range expansion. Studies conducted in the UK and Europe implicate the loss of na...

Bumble bees (Bombus spp.) are among the most important wild pollinators in temperate ecosystems in North America and Europe, and are believed to be vital to the functioning of the pollination networks in which they occur. Accordingly, evidence of their overall decline in Europe and more selective decline in the U.S. has raised concern about the lon...

Within the last two decades, notable shifts have taken place within the bumble bee (Bombus spp.) communities of North America: some species have experienced substantial, rapid declines, while others appear to be stable or even experiencing range expansion. Studies conducted in the UK and Europe implicate the loss of natural habitat and associated f...