Transient habitats limit development time for periodical cicadas.

Area of Science:

• * Ecology
• * Entomology
• * Evolutionary Biology

Background:

• * Periodical cicadas (Magicicada spp.) exhibit exceptionally long nymphal development periods of 13 or 17 years.
• * Prolonged development is potentially favored by low nymphal mortality and increased fecundity in longer-lived individuals.
• * The ecological factors limiting even longer development times remain largely unexplored.

Purpose of the Study:

• * To investigate the influence of habitat characteristics on periodical cicada adult mass.
• * To examine the impact of habitat quality and transience on cicada development duration.
• * To test the hypothesis that edge habitats yield heavier cicada adults and that habitat changes limit development time.

Main Methods:

• * Collection of newly eclosed, unfed female periodical cicadas from forest edges and interiors.
• * Measurement of adult female mass to compare edge vs. interior populations.
• * Assessment of emergence density as an indicator of habitat quality across multiple generations (1979, 1996, 2013).

Main Results:

• * Females of Magicicada septendecim emerging from forest edges were 4.9% heavier than those from forest interiors.
• * Significant variation in emergence densities was observed across sites and over time, with some sites experiencing population crashes and others explosive growth.
• * Habitat quality, indicated by emergence density, fluctuated considerably over the 17-year development cycle.

Conclusions:

• * Habitat characteristics, particularly edge effects, influence the physical condition of emerging periodical cicadas.
• * Habitat transience over the long developmental period may impose a limit on cicada life cycle duration.
• * Adult cicadas' ability to reassess and reposition offspring is crucial for tracking dynamic habitat conditions and optimizing population success.