Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Family: Pentatomoidea
Genus: Dictyotus
Species: D. caenosus
Scientific name: Dictyotus caenosus
Common names: Brown shield bug, Brown ground bug
Dictyotus caenosus is an insect in the family Pentatomoidea known as Terrestrial turtle bugs. The Pentatomoidea are often called stink bugs because when handled they emit a strong smell. The nymphs have prominent glands on the upper (dorsal) side of their abdomen, while adults have glands between the base of their legs. The chemicals may deter predators and cause other bugs to drop to the ground, but some of the chemicals produced may also act as aggregation pheromones.
Dictyotus caenosus is are a moderate pest and it is primarily a pod feeder with a preference for pods with well-developed seeds. They are known to feed on summer legumes, soybeans, mung beans, navy beans, cotton and azuki beans.
A Dictyotus caenosus adult has an 8 mm shield-shaped body that is a non-glossy, yellowish brown, rusty brown or pure brown in colour. There is a white outline on thorax and wing pads. There are alternately dark and pale markings along sides. The antennae are mostly brown to black (segments 1-2 often paler than 3-4). They are noticeably smaller than Nezara viridula (the green vegetable bug).
Dictyotus caenosus lays eggs in either small twin row or small irregular rafts containing 10-16 pale cream eggs. They are laid when the legumes are flowering.
The immature stink bugs or nymphs moult through five stages (instars) before becoming adults. Photo of the fifth stage is below.
The newly hatched nymphs are orange with black markings and are very similar to newly hatched nymphs of many other shield bugs. Larger nymphs have dark brown (sometimes almost black) heads and thoraxes, and a pale brown abdomen with transverse dark brown and pale markings at its centre. There is also a transverse pale band at the front of the abdomen.
An adult Dictyotus caenosus
Dictyotus caenosus's fifth stage or the last instar nymph.
Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0
