Alurnus

Introduction

Alurnus Fabricius (Coleoptera: Chrysomelidae: Cassidinae) contains 22 species from Central and South America and was revised by Staines (2013). These are some of the largest chrysomelid beetles ranging from 20 mm to nearly 40 mm in length. Four species have been reported feeding on palms; the other species have not been associated with any plant species (Staines 2013).

Distribution

Alurnus bicolor Staines is found in Colombia and Panamá.

Alurnus humeralis is found in Bolivia, Colombia, Ecuador, and Peru.

Alurnus ornatus Baly is found in Colombia, Costa Rica, Nicaragua, and Panamá.

Alurnus salvini Baly is found in Colombia, Costa Rica, Panamá, and Venezuela.

Hosts

Alurnus bicolor Staines feeds on Chamaedorea sp. (Arecaceae) (Staines 2013).

Alurnus humeralis feeds on Cocos nucifera L., Elaeis guineensis Jacq. (Merino & Vasquez 1963) and Astrocaryum chonta Martius (Couturier & Kahn 1992) (Arecaceae).

Alurnus ornatus Baly feeds on Chamaedorea sp. (Arecaceae) (Staines 2011b).

Alurnus salvini Baly feeds on Chamaedorea sp. (Staines 2011); Bactris gasaeipes H.B.K. (Arecaceae) (Staines 2013).

 

Life history notes

The adults of A. humeralis are diurnal and rather sluggish in motion and may be easily captured on the lower fronds of palms. Eggs are oval and flattened, and are laid in short chains of 2-10 eggs on petioles and young fronds and near the growing tip. Individual eggs slightly overlap each other. Eggs hatch in 29-43 days into 7-8 mm cream-colored larvae. The larva has 8 instars, lasting 221-254 days and obtains a maximum length of 40 mm. The insect enters a prepupa stage for 3-17 days. It then pupates inside the last larval exuvium; the pupal stage lasts 26-37 days. Total life cycle from egg to adult is from 279-351 days. Adults live from 55 -181 days and females lay from 44-181 eggs (Merino & Varquez 1963; Santos 1968).

Bibliography

Couturier, G. & F. Kahn. 1992. Notes on the insect fauna on two species of Astrocaryum (Palmae, Cocoeae, Bactridinae) in Peruvian Amazonia, with emphasis on potential pests of cultivated palms. Bulletin de l’Institut Français d’Etudes Andines 21 (2): 715-725.

Merino, M. & A. Varquez. 1963. El "gusano cogollero", Alurnus humeralis (Rosenberg) como plaga de la palma africana de aceite y su combate químico en Ecuador. Turrialba 13: 6-13.

Santos, J. V. 1968. Algunas características biológicas y etológicas del Alurnus humeralis Rosenberg "gusano chato o cogollero" de la palma africana. Turrialba 18: 115-128.

Staines, C. L. 2011. Hispines (Chrysomelidae: Cassidinae) of La Selva Biological Station, Costa Rica. In: P. Jolivet, J. Santiago-Blay, & M. Schmitt (eds.). Research on Chrysomelidae 3. Zookeys 157: 45-65.

Staines, C. L. 2013. A review of the genus Alurnus Fabricius, 1775 (Coleoptera: Chrysomelidae: Cassidinae). Insecta Mundi 0291: 1-34.