Recent reports of insect decline have raised concerns regarding population responses of ecologically important groups, such as insect pollinators. Additionally, how population trends vary across pollinator taxonomic groups and degree of specialization is unclear. Here, we analyse 14 years of abundance data (2009-2022) for 38 species of native insect pollinators, including a range of Coleoptera, Lepidoptera and Hymenoptera specialists and generalists from the tropical rainforest of Barro Colorado Island, Panama. We estimated population trends across taxonomic groups to determine whether specialist species with a narrower range of interacting mutualistic partners are experiencing steeper population declines under environmental change. We also examined the relationship between climate variables and pollinator abundance over time to determine whether differences in sensitivity to climate predict differences in population trends among pollinator species. Our analyses indicated that most pollinator populations were stable or increasing, with few species showing evidence of decline, regardless of their degree of specialization. Differences in climate sensitivity varied among pollinator species but were not associated with population trends, suggesting other environmental factors at play for tropical insect pollinators. These results highlight the need for long-term population data from diverse tropical taxa to better assess the environmental determinants of insect pollinator trends.

• Keywords
• bee, beetle, butterfly, climate change, long-term monitoring, pollinator decline,
• MeSH
• Rainforest * MeSH
• Insecta * physiology   MeSH
• Climate Change MeSH
• Pollination * MeSH
• Population Dynamics MeSH
• Tropical Climate MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Panama MeSH

Climate change poses a severe threat to many taxa, with increased mean temperatures and frequency of extreme weather events predicted. Insects can respond to high temperatures using behaviour, such as angling their wings away from the sun or seeking cool local microclimates to thermoregulate or through physiological tolerance. In a butterfly community in Panama, we compared the ability of adult butterflies from 54 species to control their body temperature across a range of air temperatures (thermal buffering ability), as well as assessing the critical thermal maxima for a subset of 24 species. Thermal buffering ability and tolerance were influenced by family, wing length, and wing colour, with Pieridae, and butterflies that are large or darker in colour having the strongest thermal buffering ability, but Hesperiidae, small, and darker butterflies tolerating the highest temperatures. We identified an interaction between thermal buffering ability and physiological tolerance, where species with stronger thermal buffering abilities had lower thermal tolerance, and vice versa. This interaction implies that species with more stable body temperatures in the field may be more vulnerable to increases in ambient temperatures, for example heat waves associated with ongoing climate change. Our study demonstrates that tropical species employ diverse thermoregulatory strategies, which is also reflected in their sensitivity to temperature extremes.

El cambio climático representa una grave amenaza para muchos taxones, con un aumento de las temperaturas medias y la frecuencia de eventos climáticos extremos pronosticados. Los insectos pueden responder a las altas temperaturas mediante comportamientos, como inclinar sus alas fuera del alcance del sol o buscar microclimas frescos locales para termorregular, o a través de la tolerancia fisiológica. En una comunidad de mariposas en Panamá, comparamos la capacidad de las mariposas adultas de 54 especies para controlar su temperatura corporal en un rango de temperaturas del aire (capacidad de amortiguación térmica), así como evaluar el máximo térmico crítico para un subconjunto de 24 especies. La capacidad de amortiguación térmica y la tolerancia se influenciaron por la familia, la longitud del ala y el colour del ala; con Pieridae y mariposas grandes o de colour más oscuro teniendo la capacidad de amortiguación térmica más fuerte, pero Hesperiidae, mariposas pequeñas y de colour más oscuro tolerando las temperaturas más altas. Identificamos una relación entre la capacidad de amortiguación térmica y la tolerancia fisiológica, en la que las especies con mayores capacidades de amortiguación térmica tenían una menor tolerancia térmica, y viceversa. Esta interacción implica que las especies con temperaturas corporales más estables en el campo pueden ser más vulnerables a los aumentos en las temperaturas ambientales, por ejemplo, las olas de calor asociadas con el cambio climático actual. Nuestra investigación demuestra que las especies tropicales emplean diversas estrategias de termorregulación, las cuales también se reflejan en su sensibilidad a las temperaturas extremas.

• Keywords
• Lepidoptera, buffering ability, butterfly, critical thermal maximum, ectotherm, insect, thermal ecology, thermal limits,
• MeSH
• Climate Change MeSH
• Butterflies * physiology   MeSH
• Cold Temperature MeSH
• Temperature MeSH
• Body Temperature Regulation MeSH
• Hot Temperature MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH