Small Milkweed Bug - Spilostethus sp.
Family Lygaeidae
This page contains pictures and information about Small Milkweed Bugs that we found in the Brisbane area, Queensland, Australia.
- Body length 12mm
- The Small Milkweed Bug adults are orange-red in colour, with black wings. Their antennae and legs are black in colour. They have relatively large eyes and narrow body. The nymphs are black in colour with blood red abdomen. The adults and nymphs found shelter in large numbers on and around the Milkweed seed pockets.
- We found two different red bugs on the Milkweed plant. The Large Milkweed bugs, with black patterns on orange colour, larger in size. And this Small Milkweed Bugs, with no patterns on wings and thorax, a bit smaller in size. They just stayed together peacefully sucking the juice from the Milkweed plants.
- Their nymph life style is not much different from the aphids. The famous Wanderer Butterflies are not eatable since their caterpillars eat the milkweed plants and store the toxic in body. It is logical to assume that they those bugs are not eatable too. This is no wonder that both the Milkweed Bugs have the warning colour patterns.
- Notice their sucking mouths, the adults and nymph suck juice from the Milkweed plants. The Milkweed plants is supposed to evolved the toxic juice to against the plant-eater. However, once the insects evolved the mechanisms to overcome the toxic and store the toxic in their own body, the bugs themselves become not eatable too. The toxic host plants become their paradise. They feed freely and openly on the plants, without fear of predators. The only thing they have to do to to further evolve the warning colour to warn-off the predators.
- At night, the Milkweed Bugs family hiding inside the milkweed seed pocket. When disturbed, they come out and run away. Some of them quickly drop to the ground.
- Reference:
- 1. Spilostethus sp. - Insects of Townsville, Australia - Graeme Cocks, 2004.
