Sinea diadema
spined assassin bug

Sinea diadema is typically found in Southern North America, namely in the Southern United States and Northern Mexico. (Arnett, 1993)

Sinea diadema is generally found in grasslands, gardens, and fields. They are found living among flowers and in crops. ()

Sinea diadema has a long, narrow head that supports a short beak, formed by three segments. Also found on the head are slender antennae, each composed of four segments. The large size of the head is to support the beak that is so necessary for prey capture and consumption. Unlike other assassin bugs that are often bicolored, Sinea diadema is dark brown or a dull red. The eyes are reddish brown. The front legs are slightly swollen and covered with spines. The abdominal area is expanded, flat, and displays a pale spot on the rear margin of every segment. Because the middle of the abdomen is so wide, the wings cannot completely cover the entire body. (Lyon, 2002; Mahr, 1996)

After hatching from the egg, Sinea diadema develops into a nymph, resembling the adult form, but without wings. The nymph molts five times, and will hibernate just before the last molt to emerge in the summer season as a reproductive adult. (Mahr, 1996; Texas Cooperative Extension, 1999)

Although both vision and antennal olfaction are important to various life processes, no further information was available for specific mating systems of Sinea diadema.

The female Sinea diadema deposits large amounts of brown, cylindrical eggs in an upright position. These eggs are usually located on a leaf or within the soil, and are covered with a reddish brown secretion. (Arnett, 1993)

After laying the eggs, the female and male have no further parental contact with the young.

Antennal olfaction plays a large role in the finding of a habitat. Not only is this sensory input important for the habitat location, it is also important for locating areas of prey and individual prey organisms. Studies have shown that in some cases, olfaction is more important than vision for locating habitats. (Freund and Olmstead, 2000a; Freund and Olmstead, 2000b)

Antennal olfactions and vision are key to the lifestyle of Sinea diadema. The ability to sense vibrations is also important, especially when it comes to enemy avoidance. However, studies have shown that vision is the most important sense for avoiding enemies. (Freund and Olmstead, 2000a; Freund and Olmstead, 2000b; Taylor and Schmidt, 1996)

Sinea diadema preys on organism such as aphids, caterpillar eggs, leafhoppers, lady bugs, and asparagus beetle eggs and larvae. The sharp beak mouthpart on the head is used to stab into the prey, allowing Sinea diadema to pierce through the prey's outer covering and then to suck out the body fluids. (; Lyon, 2002; Mahr, 1996; Texas Cooperative Extension, 1999)

The dark brown and dark red coloring allows for cryptic coloration. Studies have shown that if Sinea diadema is in a state of starvation, it will resort to cannibalism, namely on the siblings that surround it. (Freund and Olmstead, 2000a)

Because Sinea diadema feeds on many pest insects that destroy valuable crops, they are a desired species. They contribute to the natural balance of their habitat and control insect populations in the process.

These bugs attack many agricultural and horticultural pests, so are beneficial to human interests. (Lyon, 2002; Mahr, 1996; Texas Cooperative Extension, 1999)

Although these bugs typically avoid humans, if roughly handled, Sinea diadema can bite. The bite may be painful, but not deadly. (Texas Cooperative Extension, 1999)

This species is not believed to need any special conservation.