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Can Cities Activate Sleeper Species and Predict Future Forest Pests? A Case Study of Scale Insects
Steven D Frank1, Michael G Just1
1Department of Entomology and Plant Pathology, Campus Box 7613, North Carolina State University, Raleigh, NC 27695, USA.
Insects
|February 29, 2020
Summary
Warming temperatures awaken "sleeper species," native insects that become pests. Urban heat islands reveal which species may become forest pests due to climate change, aiding in pest management strategies.
Area of Science:
- Ecology
- Entomology
- Climate Change Biology
Background:
- Sleeper species are native or naturalized organisms that become invasive pests under environmental change.
- Climate warming is predicted to increase arthropod damage in forests by activating sleeper species.
- Urban heat islands create warmer microclimates, simulating future climate conditions for urban trees and pests.
Purpose of the Study:
- To identify arthropod species that become pests of urban trees as potential sleeper species for forest monitoring.
- To investigate the impact of urban heat island effects on insect pest populations and their ecological interactions.
- To use urban ecosystems as model systems for studying climate warming effects on insect herbivores.
Main Methods:
- Case studies of two scale insect species, *Melanaspis tenebricosa* and *Parthenolecanium quercifex*, on urban trees in the US.
- Analysis of how urban heat island effects (temperature increases) influence insect survival, reproduction, and natural enemy interactions.
- Examination of phenological mismatches and drought stress impacts on insect pest densities.
Main Results:
- *Parthenolecanium quercifex* density increased up to 12-fold on urban willow oaks with 2°C warming, due to higher survival and adaptation.
- Phenological mismatch between *P. quercifex* and its parasitoids led to increased egg production in warmer urban conditions.
- *Melanaspis tenebricosa* density increased up to 300-fold on urban red maples with 2.5°C warming, driven by direct temperature effects and drought stress.
Conclusions:
- Urban trees infested by scale insects experiencing warming demonstrate the 'sleeper species' phenomenon.
- Species that thrive as pests in urban heat islands are candidates for future forest pests under climate change.
- Monitoring urban pest species offers a pragmatic approach to anticipate and prepare for climate-driven forest pest outbreaks.
