Urban Heat and Insect Emergence Timing

ISEF Category: Earth and Environmental Sciences

Subcategory: Environmental Effects on Ecosystems  ·  Difficulty: Intermediate  ·  Setup: Home Setup  ·  Time: 1 to 2 Months

The Hook

Cities stay warmer than nearby forests and fields, even at night. That extra heat can act like a clock for insects. If you can track when cicadas or fireflies appear across warm and cool neighborhoods, you can test whether urban heat speeds up their emergence. This project turns public sightings and satellite data into a real ecology study.

What Is It?

This project asks whether the urban heat island changes the timing of insect life events. A heat island is a city area that runs warmer than nearby rural land because of pavement, dark roofs, and less shade. For insects, temperature affects development speed. Think of it like an oven timer. When the environment warms up, the timer can move faster.

You can test that idea with public data. iNaturalist gives you observation timestamps for cicadas or fireflies, and Landsat gives you land surface temperature, or LST, which is a satellite estimate of how hot the ground is. A degree-day model turns accumulated heat into a prediction of when insects should emerge. You compare warm and cool locations, then see whether the model matches the sightings.

Why This Is a Good Topic

This is a strong science fair topic because you can ask a real ecological question with free data and clear numbers. The phenomenon is measurable, since you can compare observation dates, satellite temperature, and predicted emergence timing across places. It connects to urban ecology, climate adaptation, and insect behavior, all of which matter in real cities. You can learn data cleaning, mapping, and basic modeling without needing a lab bench.

Research Questions

• How does urban heat-island intensity affect the first observation date of cicadas in a city neighborhood?
• What is the effect of land surface temperature on the emergence timing of fireflies across urban, suburban, and rural sites?
• Does a degree-day phenology model predict cicada observations more accurately in warmer locations than in cooler ones?
• To what extent does the timing gap between urban and rural insect sightings change across years with hotter summers?
• Which urban land-cover features, such as tree cover or impervious surface, best explain differences in firefly emergence timing?
• How does the choice of temperature metric, land surface temperature versus air temperature, change the strength of the emergence model?

Basic Materials

• Laptop or desktop computer with internet access.
• iNaturalist account and access to observation records.
• USGS Landsat access through EarthExplorer or Google Earth Engine.
• Spreadsheet software such as Google Sheets or Excel.
• Free mapping tool such as QGIS.
• Digital notebook for recording filtering rules, dates, and site labels.
• Optional: NOAA climate data access for cross-checking local temperature patterns.

Advanced Materials

• Laptop or desktop computer with internet access.
• iNaturalist observation export files for your target species.
• Landsat surface temperature products or processed raster files.
• R or Python for cleaning data and fitting phenology models.
• QGIS or ArcGIS for spatial joins and map layers.
• NOAA or PRISM climate data for air temperature comparison.
• Land cover data from USGS, NOAA, or a city open-data portal.
• Statistical package for regression, mixed models, or model comparison.

Software & Tools

• iNaturalist: Finds public observation records with timestamps and locations for your target species.
• USGS EarthExplorer: Downloads Landsat imagery and temperature-related raster layers.
• QGIS: Maps sightings and extracts land surface temperature around each observation point.
• Google Sheets: Organizes records, filters out bad observations, and builds early plots.
• R: Fits degree-day phenology models and compares timing across site types.

Experiment Steps

1. Choose one insect group and define the emergence event you will measure, such as first adult sighting or first seasonal peak.
2. Build a site list that spans a clear urban-to-rural heat gradient, then decide how you will classify each location.
3. Collect iNaturalist observations and filter out records with uncertain dates, duplicate sightings, or poor location precision.
4. Match each sighting to a satellite temperature value and decide whether you will use a single date, a seasonal average, or accumulated heat.
5. Design your degree-day model, including the baseline temperature, the heat accumulation window, and the outcome you will predict.
6. Plan controls and comparisons that test whether temperature explains timing better than city size, year, or habitat cover.

Common Pitfalls

• Using all observations without filtering, which mixes true emergence records with stray sightings and repeated reports.
• Comparing city and rural sites with very different search effort, which can make people’s observation habits look like biology.
• Matching satellite temperature to the wrong date, which breaks the link between heat exposure and emergence timing.
• Ignoring location uncertainty in iNaturalist records, which can assign a sighting to the wrong neighborhood.
• Fitting a degree-day model without checking the baseline temperature, which can produce a nice-looking curve that has no biological meaning.

What Makes This Competitive

A stronger project will do more than compare warm and cool places. You can test multiple temperature metrics, compare model fits, and show that your result still holds after you control for sampling bias and land cover. A competitive entry also asks a sharper question, like whether fireflies and cicadas respond differently to urban heat. Clear maps, clean filtering rules, and careful statistics can turn a simple idea into a serious ecology study.

Project Variations

• Use firefly observations in one metro area and compare emergence timing across park, suburb, and downtown sites.
• Swap landsat surface temperature for NOAA or PRISM air temperature and test whether the model changes.
• Compare one species across two cities with different heat-island strength to see whether the timing shift scales with urban warming.

Learn More

• USGS Landsat Collection: Search the USGS site for Landsat surface temperature products and guidance on how to read them.
• iNaturalist Research Grade Observations: Use iNaturalist help pages to learn how to export observation data for analysis.
• NOAA Climate Data Online: Find local temperature records and climate normals for cross-checking satellite-based heat patterns.
• NASA Earthdata: Search for tutorials on land surface temperature and urban heat islands.
• Phenology journal: Search the journal for review articles on insect emergence timing and temperature-driven models.
• OpenStax Biology 2e: Use the ecology and climate sections for a free refresher on species responses to environment.