Portrait of a killer: Arilus cristatus, the wheel bug

Arilus cristatus, the wheel bug, is a truly impressive insect and one that I was fortunate enough to encounter today on my way into work. I came across this spectacular individual crossing the street outside our building this morning and collected it so I could take some photos later in the lab.

Wheel bugs are a a type of large assassin bug, a diverse group of true bugs in the family Reduviidae. As their name suggests, assassin bugs are deadly predators, feeding voraciously on other arthropods. Like all hemipterans, the mouthparts of assassin bugs consist of a long, segmented tube called a rostrum. Most hemipterans use this piercing apparatus to suck sap from the stems of plants, but the assassin bugs put it to a far more sinister use, empaling their prey and injecting lethal saliva packed with digestive enzymes which liquefy the unfortunate victim’s innards. The nutrient-rich soup is then sucked out with the rostrum acting rather like a straw.

Arilus cristatus and most of the other assassin bugs are beneficial insects, feeding on numerous arthropod pests. While the larger species like the wheel bug can inflict a painful bite when provoked, most reduviids are generally harmless to humans. However, members of the subfamily Triatominae are haematophagous and make a living drinking the blood of vertebrates, including humans. Indeed, triatomines are commonly called “kissing bugs” due to their habit of biting people on the face while they sleep. Unfortunately, they are potential vectors for the parasitic trypanosome that causes Chagas disease, a dangerous tropical illness.

Just published: A new fossil cricket of the genus Proanaxipha in Miocene amber from the Dominican Republic

The following paper was published today in the journal ZooKeys: Heads SW, Penney D, Green DI (2012) A new fossil cricket of the genus Proanaxipha in Miocene amber from the Dominican Republic (Orthoptera: Gryllidae: Pentacentrinae). ZooKeys 229: 111–118, doi: 10.3897/zookeys.229.3678. [pdf]

In the paper we describe Proanaxipha madgesuttonae, a new species of pentacentrine cricket from Early Miocene Dominican amber. The holotype (a male) is exceptionally well preserved, as is typical of inclusions in Dominican amber, and retains its original color pattern and fine setae on the pronotum, legs, cerci, etc. In addition, the apical parts of the phallic complex (the median epiphallic process and the distal lobes of the ectoparameres) can be seen in ventral view, protruding slightly from the genital capsule.

Morphologically, P. madgesuttonae and the type species P. latoca (described by Vickery & Poinar, 1994) share many features in common with some species currently placed in the extant genus Nemobiopsis and while the precise relationships of these taxa have yet to be fully investigated, it seems likely that Proanaxipha and Nemobiopsis are closely related. Nevertheless, the status of Nemobiopsis and Proanaxipha as separate, monophyletic genera is questionable (Nemobiopsis in particular is rather ill-defined) and a thorough revision of these and related genera is needed.

Additional references

Vickery VR, Poinar GO (1994) Crickets (Grylloptera: Grylloidea) in Dominican amber. Canadian Entomologist 126: 13–22, doi: 10.4039/Ent12613-1.