Stigmus
Panzer, 1804
Species Guides
1- Stigmus americanus(aphid wasp)
Stigmus is a of aphid wasps containing over 20 described . These small predatory are distributed across four major zoogeographic regions, with highest diversity in the Nearctic and Palearctic. They are specialized of aphids and nest in wood cavities. The genus is characterized by distinctive wing venation including a large stigma and elongate marginal .
Pronunciation
How to pronounce Stigmus: //ˈstɪɡməs//
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Identification
Distinguished from similar Carinostigmus by: vertex with micropore field; normal hindwing submedian ; usually incomplete occipital carina; degenerative interantennal ; and petiole with carinae. Forewing has two or fewer discoidal cells, one recurrent , large stigma, and elongate marginal cell closed apically. Petiole length significantly longer than width in view.
Images
Habitat
Nests in wood including twigs, dead trees, and structural lumber. Uses abandoned borings made by other insects (principally larvae), self-made borings in pith of twigs or stems, and abandoned galls of other insects.
Distribution
Worldwide across Nearctic, Palearctic, Oriental, and Neotropical regions. Majority of in Nearctic (10 species, 2 ) and Palearctic (10 species); Oriental region (6 species, 2 subspecies); Neotropical region (2 species). One species spans both Palearctic and Oriental regions; one species spans both Nearctic and Neotropical regions. China: Yunnan and Shaanxi provinces.
Diet
Predatory towards aphids found on woody plants. Some have been observed preying on Rhopalosiphum and Aphis on herbaceous plants.
Host Associations
- aphids on woody plants - prey
- Rhopalosiphum on herbaceous plants - prey
- Aphis on herbaceous plants - prey
Life Cycle
Nests consist of linear series of separated by partitions of small pieces of pith from the wood substrate.
Ecological Role
of aphids; nests in pre-existing cavities or self-made borings in plant material.
Similar Taxa
- CarinostigmusBoth in subtribe Stigmina; distinguished by vertex without micropore field, different petiole structure, and other morphological characters as detailed in identification.