Saturday 28 April 2018

Cotesia nuellorum: A new species of Braconid Wasp from Texas.

Braconid Wasps are small parasitoid wasps (Wasps whose larvae grow inside the bodies of a living animal host) targeting a variety of Insect and Spider species. They are unusual in that they will lay multiple eggs within the same host (most parasitoid Wasps lay a single egg on each host), thereby allowing multiple larvae to mature within a large host, which is not necessarily killed in the process. Braconid Wasps are often fearsome in appearance, but are harmless, other than to targeted host species, as they lack stings. Members of the genus Cotesia target large Butterfly and Moth caterpillars, including many species considered to be significant agricultural pests, making them of considerable interest to entomologists.

In a paper published in the journal ZooKeys on 5 February 2018, James Whitfield of the Department of Entomology at the University of Illinois, Urbana, and Robert Nuelle Jr. and Robert Nuelle III, of the Sam Houston State Natural History Collections Huntsville, describe a new species of Cotesia from Texas.

The new species is named Cotesia nuellorum, in honour of Robert Nuelle Jr. and Robert Nuelle III, who discovered the first examples of the species, raised from an infected Hickory Horned Devil caterpillar, Citheronia regalis, found in the Sam Houston National Forest in Walker County, Texas, and subsequently from an infected Luna Moth, Actias luna, from the same location. 

Larva of Citheronia regalis with emerged larvae and cocoons of Cotesia nuellorum, in rearing container. Robert Nuelle Jr. in Whitfield et al. (2018).

The adult Wasps reach 2.0-2.2 mm in length, with males slightly smaller than the females, and are black in colour with dark brown markings and brown legs. The species was found in an area of managed woodland in Texas, but is likely to be more widely distributed, as both known host species are widespread in North America and known to be prone to Braconid infections across their range.

Cotesia nuellorum, adult female in lateral view. Whitfield et al. (2018).

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