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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Systematic Entomology Laboratory » Research » Publications at this Location » Publication #351159

Research Project: Systematics of Moths Significant to Biodiversity, Quarantine, and Control, with a Focus on Invasive Species

Location: Systematic Entomology Laboratory

Title: The role of herbivorous insects and pathogens in the regeneration dynamics of Guazuma ulmifolia in Panama

item SOLE, RAPHAELE - University Of Montpellier
item GRIPENBERG, SOFIA - University Of Oxford
item LEWIS, OWEN - University Of Oxford
item MARKESTEIJN, LARS - Bangor University
item BARRIOS, HECTOR - Universidad De Panama
item RATZ, TOM - University Of Edinburgh
item CTVRTECKA, RICHARD - University Of South Bohemia
item BUTTERILL, PHILIP - University Of South Bohemia
item SEGAR, SIMON - University Of South Bohemia
item Metz, Mark
item DAHL, CHRIS - University Of South Bohemia
item RIVERA, MARLENY - Universidad De Panama
item VIQUEZ, KARINA - Universidad De Panama
item FERGUSON, WESSLEY - Universidad De Panama
item GUEVARA, MAIKOL - Universidad De Panama
item BASSET, YVES - Universidad De Panama

Submitted to: Nature Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/19/2019
Publication Date: 3/6/2019
Citation: Sole, R., Gripenberg, S., Lewis, O.T., Markesteijn, L., Barrios, H., Ratz, T., Ctvrtecka, R., Butterill, P.T., Segar, S.T., Metz, M., Dahl, C., Rivera, M., Viquez, K., Ferguson, W., Guevara, M., Basset, Y. 2019. The role of herbivorous insects and pathogens in the regeneration dynamics of Guazuma ulmifolia in Panama. Nature Conservation. 32:81-101.

Interpretive Summary: The bay cedar tree is an important species in Central American agroforestry. This study investigated the impact of seed- and seedling-feeding insects on the regeneration of bay cedar communities. The findings suggest that early seeds are most susceptible to insect damage, but insect damage is less of a concern than inclement weather.

Technical Abstract: A significant proportion of the mortality of rainforest trees occurs during early life stages (seeds and seedlings), but mortality agents are often elusive. Our study investigated the role of herbivorous insects and pathogens in the early regeneration dynamics of Guazuma ulmifolia (Malvaceae), an important tree species in agroforestry in Central America. We reared predispersal insect seed predators from G. ulmifolia seeds in Panama. We also carried out an experiment, controlling insects and pathogens using insecticide and/or fungicide treatments, as well as seed density, and compared survivorship of G. ulmifolia seeds and seedlings among treatments and relative to untreated control plots. We observed (1) high pre-dispersal attack (92%) of the fruits of G. ulmifolia, mostly by anobiine and bruchine beetles; (2) negligible postdispersal attack of isolated seeds by insects and pathogens; (3) slow growth and high mortality (>95%) of seedlings after 14 weeks; (4) low insect damage on seedlings; and (5) a strong positive correlation between seedling mortality and rainfall. We conclude that for G. ulmifolia at our study site the pre-dispersal seed stage is by far the most sensitive stage to insects and that their influence on seedling mortality appears to be slight as compared to that of inclement weather. Thus, the regeneration of this important tree species may depend on effective primary dispersal of seeds by vertebrates (before most of the seed crop is lost to insects), conditioned by suitable conditions in which the seedlings can grow.