Understanding olfactory cues in host location and dispersal range of the filth fly parasitoid Spalangia cameroni (Hymenoptera:Pteromalidae) to improve the use as sustainable biological control agents for fly control on livestock operations

Understanding olfactory cues in host location and dispersal range of the filth fly parasitoid Spalangia cameroni (Hymenoptera:Pteromalidae) to improve the use as sustainable biological control agents for fly control on livestock operations

Summary

Pupal parasitoids are often used as sustainable biological control options for filth fly pests on livestock operations. Filth flies, such as stable flies (Stomoxys calcitrans) and house flies (Musca domestica), are mechanical vectors of disease and can cause pain and losses of condition to livestock. Conventional control of these pests has relied on high doses of various insecticides. Filth fly pests are becoming increasingly resistant to many licensed insecticides and the increase of chemical use is harmful to the environment. The purpose of this project is to improve the use of pupal parasitoids of filth flies as part of a sustainable biological control program on livestock operations. Impacts of this research include increasing the effectiveness of the parasitoids, reducing exposure of humans and animals to toxic insecticides, managing insecticide resistance by improving sustainable biological control options and ultimately reducing cost and increasing the use of these parasitoids to manage filth flies. Current work is focusing on experimental design and insect rearing to facilitate commencement of funded research.

Objectives/Performance Targets

The goal of this research is to (1) define the odor cues which influence host location by filth fly parasitoids, (2) assess dispersal to hosts sites from release locations in the field, and (3) increase the operator awareness of biological control of filth flies.

Goal (1): Define the odor cues which influence host location by filth fly parasitoids

1) Objective 1: To assess the attraction of S. cameroni to the larvae of house flies at different concentrations.

2) Objective 2: To assess the attraction of S. cameroni to manures of three different farm animals and the attraction to the interaction between developing larvae in the manure.

Goal (2): Assessment of dispersal to hosts sites from release locations in the field

3) Objective 3: To assess dispersal range of S. cameroni when hosts are immediately present at many distances and when hosts are not immediately available.

Goal (3): Outreach and extension activities to increase the operator awareness of biological control of filth flies.

4) Objective 4: Development of an extension publication to assist farmers in the use and selection of parasitic wasps for filth fly control.

Accomplishments/Milestones

Preparations for this project began January 2012. Thus far, the project has remained consistent with the suggested timeline in the proposal submission.

Field dispersal experiment protocols have been refined and field release sites have been identified. Site selection was difficult as the field site could not be in close proximity to livestock operations where natural levels of parasitism may confound the results. The site selected is the USDA, ARS-CMAVE location in Gainesville, Florida. This locale has sufficient space to run the dispersal experiments and will allow for consistent monitoring of substrates and releases. Upon further inspection of the dispersal methods, it has been determined that a linear release (substrate and hosts provided in a single straight line from a parasitoid release site) will be used instead of a circular array. This will limit the number of potential environmental variables (directionality, wind, light, etc.) that could significantly affect the results. Fluon has been tested on the substrate holding bins and will be sufficient to deter fire ants from predating on the house fly host pupae.

The 2010 colony of Spalangia cameroni and the USDA, ARS – CMAVE susceptible house fly colony have been increased to a sustainable level for field releases. Spalangia cameroni has a life cycle of about four weeks and requires a significant amount of time to increase in total colony numbers. The standard protocol for rearing this species includes providing parasitoids with free access to 5000 house fly pupae hosts killed by heat shock for one week. However, better parasitism levels are reached if live hosts are provided. This requires tri-weekly maintenance to ensure that hosts that are not parasitized do not emerge prior to the next servicing.

Impacts and Contributions/Outcomes

Results from this study will be communicated to farmers and extension agents through a single reference document created to assist livestock operators in selecting and implementing the use of parasitic wasps for filth fly control on their facilities. This information will be published through the EDIS system at the University of Florida, an online database.

Additionally, a booth at the Florida Small Farms Conference which annually hosts over 750 attendees will be reserved to distribute this information to stakeholders who will use it to improve their sustainable fly control programs.

It is expected that the results of this research will also be submitted for publication in a scientific journal (i.e., Journal of Economic Entomology).

Collaborators: