Reduced body sizes in climate-impacted Borneo moth assemblages are primarily explained by range shifts

Area of Science:

• Ecology
• Climate Change Biology
• Zoology

Background:

• Climate warming drives changes in species distribution and physiology.
• These changes can impact community body-size structures.
• Tropical ecosystems are particularly vulnerable to climate shifts.

Purpose of the Study:

• To assess the relative contribution of species redistribution and within-species size changes to community body-size restructuring.
• To investigate how climate warming affects tropical moth assemblages.
• To quantify the impact of range shifts versus physiological changes on body size.

Main Methods:

• Resurvey data from 1965 and 2007 for geometrid moth assemblages on Mt. Kinabalu, Borneo.
• Analysis of over 8000 individual moth wing lengths.
• Quantification of species range shifts and within-species size changes.

Main Results:

• Significant mean wing-length reduction observed across moth species (1.3% per species).
• Overall community mean forewing length decreased by approximately 5%.
• Species range boundary shifts were the dominant factor (3.9%), followed by within-boundary changes (0.5%) and within-species shrinkage (0.6%).

Conclusions:

• Range shifting of species is the predominant driver of body-size reorganization in tropical moth communities under warming.
• While species redistribution is key, physiological responses (within-species size changes) also contribute to community size shifts.
• Understanding both factors is crucial for predicting ecological responses to climate change.