Aleiodes arbitrium (Townsend)









Mummified host caterpillar 









 Female lateral habitus




Metasomal terga 2+3, dorsal view



Diagnostic features of adult wasp

Body length 5.7 mm; antenna with 41 flagellomeres; head mostly black; malar space just slightly wider than basal width of mandible; ocelli small, ocell-ocular distance slightly wider than width of lateral ocellus; occipital carina complete but weak at vertex; mesosoma mostly light yellowish brown, except propodeum black; wings clear; mesopleuron granulate; apex of hind tibia with setae normal, not flattened; propodeum rugulose basally, granulate apically, with median propodeal carina present; tarsal claw simple; metasomal terga mostly black, except terga 2 and 3 often each with an oval-shaped off white marking; metasomal terga 1-3 costate, median carina complete to end of tergum 2; ovipositor about 0.7 x length of hind basitarsus.

Biology and rearing records

Aleiodes arbitrium has been reared from the mummified caterpillars of an unidentified Geometridae found on Diplazium costale (Dryopteridaceae), and from a Hypena species (Noctuidae) feeding on Phenax rugosus (Urticaceae). It is a solitary koinobiont endoparasitoid.


This species is known only from localities near the Yanayacu Biological Research Station, Napo Province, Ecuador, at 2163 meters elevation.

Similar species

Aleiodes arbitrium is assigned to the circumscriptus species-group but it is not likely to be confused with any other species because of its distinctive color patterns. Characteristics separating A. arbitrium from other Ecuadorian species are given by Townsend and Shaw (2009).


Aleiodes arbitrium is one of the more commonly encountered Aleiodes species at the Yanayacu Biological Research Station. In addition to having been reared from host mummies at least eight times, this species has also been sampled by Malaise trap and yellow bowl traps.


Townsend, A. and S.R. Shaw. 2009. Nine new species of Aleiodes reared from caterpillars in the northeastern Andes of Ecuador (Hymenoptera: Braconidae: Rogadinae). Journal of Insect Science 9, Article 33, pages 1-21. Available online: