Nicholas Mills, Professor

Closed (1) Does agricultural intensification affect South American insect diversity?

Applications for Spring 2018 are now closed for this project.

My research is focused on quantifying the cascading effects of land-use intensification on insect community structure both within agriculture systems and in adjacent non-agricultural ecosystems. Uruguay has increased its total land area under cultivation in the past ten years; the majority is under continuous cultivation. Mixed agriculture/livestock rotations are an alternative system with a long history in Uruguay. This type of land use is less intensive and more sustainable; understanding the effect on insect community structure and functional diversity is important but unknown. Agricultural land-use also has implications for mobile insect species in adjacent natural areas. The spillover from natural areas to agriculture has been studied, but there is far less research on spillover effects from agriculture to natural systems. I collected two years of insect trapping data from the summer months of 2016 and 2017 in sorghum and paired adjacent natural areas. Land-use and habitat are being categorized to include their effects. To quantify the cascading effects of local and landscape land-use intensity on biodiversity, new methodologies being adopted by landscape ecologists will be incorporated, namely Structural Equation Models. This research can help delineate the effects of land-use intensity at local and landscape scales on insect functional diversity which has broad implications for biodiversity and biological control as an ecosystem service.

The most pressing task this fall will be codifying the insect collection from my research in Uruguay so that the information can be analyzed. Students will work directly with pinned insects. There is potential for the right person to with prior knowledge of coding and/or statistics with a strong desire to learn more to work in R and begin working with data from this project under my supervision. There is also potential for someone to work with mapping polygons on landscapes and land-use analysis in R.

Day-to-day supervisor for this project: Sara Emery, Ph.D. candidate

Qualifications: 1. ATTENTION TO DETAIL (required): The pinned insect specimens are fragile and will eventually go to the Essig Museum of Entomology. Care with fragile specimens is paramount. Additionally, it is essential that the information from each specimen is digitized accurately. 2. PUNCTUALITY (required): This work can be done in a flexible time frame, but students must be willing to work on a consistent schedule so I can be available when questions arise. 3. TEAM WORK (required): Students must be willing to coordinate with others during this ongoing project. This requires communication both with me and with other students working on the project. You must respond to emails in a timely manner.

Weekly Hours: 6-9 hrs

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Closed (2) Can induced plant defenses limit the abundance of an invasive insect?

Applications for Spring 2018 are now closed for this project.

The Light Brown Apple Moth (LBAM) is an invasive leafrolling moth from Australia that was first found in California in 2007. Worries over the effects of this invasive species on California agriculture have prompted research into its potential geographic range and biological control factors, such as natural insect parasitism and diseases. Over the past 10 years, LBAM has experienced a decline that is unusual for an invasive species, a decline which is not fully explained by parasitism and disease. This project examines a new potential limiting factor for LBAM; induced plant defenses. Plants respond to insect herbivory by increasing defensive chemicals such as iridoid glycosides and tannins. To investigate the possible effects of induced plant defenses on the life history performance of LBAM, we are running cage experiments. These involve adding varying levels of inducing larvae to plants, allowing them to feed, then allowing a single bioassay larva to feed on leaves taken from the induced plants to determine if higher damage levels are associated with lower larval weight gain in the bioassay larvae. We are also doing field sampling of known LBAM populations around the Bay Area, which includes counts and collections for parasitism analysis.

Running an experiment requires maintaining a colony of LBAM. The colony must be maintained in a healthy state to provide experimental individuals for the fall and spring experimental season, as specific larval instars are necessary for accurate bioassay performance.

Colony maintenance tasks include:
1) Cutting eggs from oviposition cups
2) Picking LBAM pupae from diet cups
3) Making LBAM diet/honey
4) Maintaining various greenhouse plants for colonies/experiments

Other tasks include:
1)Data entry
2)Vial sanitizing

In addition, there may be some work recording emergences from field collected LBAM populations, depending on how many hours a week is needed for colony maintenance.

Day-to-day supervisor for this project: Katherine Patterson, Staff Researcher

Qualifications: Anyone interested in working in an insect biology lab is welcome to apply. The project involves working with insects, which are living organisms and therefore require timely maintenance. Punctuality, precision, and patience are essential.

Weekly Hours: to be negotiated

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