Description

Amaurochrous cinctipes is a stink bug (family Pentatomidae) in the group collectively known as turtle bugs (subfamily Podopinae). Adults of this species range from 4 mm to 6 mm in length, with broad oval bodies that are brownish black in color. The legs are orange near the tips (tarsi) with additional orange bands on the middle segments (tibiae), and dark brown near the bases (femora). The eyes are large and bulging. The antennae are five-segmented. Turtle bugs differ from other stink bugs in possessing greatly enlarged scutellums, an oval shield at the rear of the thorax. This shield covers most of the fore and hind wings. The forewings are partially thickened, as typical for other members of this group of true bugs. The hindwings are membranous. Turtle bugs possess four-segmented beaks that are tucked under the body behind the head when not deployed for feeding. Adults are capable of flight. Immature stages have not been described in detail.

Amaurochrous cinctipes is one of three turtle bug species occurring Louisiana, based on specimens in the Louisiana State Arthropod Museum. Amaurochrous dubius is extremely similar to A. cinctipes, and doubt exists about whether the two species are sufficiently distinct to warrant separate species status. Amaurochrous magnus is substantially larger; 8 mm to 10 mm in length. All three species are widespread in southern United States but are rarely encountered or collected. More than 250 species of turtle bugs occur worldwide. The group is much more diverse in the Old World. North American species are all somber brown or black in color, but some Eurasian species, particularly in the genus Graphisoma, are strikingly marked with orange or red and black bands.

Life Cycle

Turtle bugs are hemimetabolous, as are all members of the order Hemiptera. Development involves three life stages: egg, nymph and adult. No published studies exist that describe the detailed biology of Amaurochrous species, but the life cycle is likely similar to that of other plant feeding stink bugs in the family Pentatomidae. Females lay eggs in clusters on the underside or surface of leaves. The egg stage lasts five to 14 days and is shorter during warm weather. Wingless nymphs hatch from the eggs and pass through five growth stages (instars), each separated by a molt. Upon reaching the final instar, nymphs molt into adults with functional flight wings. Nymphs and adults feed by piercing the epidermis of host plants with their beak. Salivary enzymes injected into the plant tissue begin the process of digestion and the partially liquified plant matter is sucked into the head by the action of powerful muscles inside the front of the head. Overwintering strategies of turtle bugs are not well documented.

Ecological Significance

Amaurochrous cinctipes and several related turtle bug species are found throughout the southeastern U.S. but are seldom collected. They occur in low lying habitats such as marshes, ponds, and lake shores with semiaquatic herbaceous vegetation, including various wetland grasses, sedges, and rushes. Host plants of various turtle bugs in related genera include nutsedges (Cyperus), rushes (Juncus), and various grasses (Poaceae). Host plants of Amaurochrous are not documented but likely include some combination of lowland monocots recorded for other genera. Many Eurasian turtle bugs in other genera feed on woody plants, but North American species appear limited to herbaceous monocots. Some species of Podopinae have been recorded on rice (Oryza sativa), but none are considered pests. Additional collecting and study of turtle bugs in Louisiana may reveal more about their mysterious life cycles and habits. Collecting using sweep nets in wet meadows, bogs and along edges of water bodies is likely the most productive method of obtaining specimens.