Ashy Gray Lady Beetle, Olla v-nigrum

June 23, 2010

This unusual ladybug is actually a completely different species from common red ladybugs. Although in the same family (Coccinellidae), it is one of many variations. Coccinellids range from typical red with black spots to spotless to yellow or black or even mottled brown. Some coccinellids are of the stereotypical ladybug shape, while others resemble more elogated beetles with long legs or tiny, “moving flower seeds.” Female ladybugs are generally larger than the males.

This beetle lays tiny, yellowish eggs on the underside of a leaf near a food source for the young, such as aphids. In 3 to 5 days, the young hatch in the form of tiny, fiercely spiky larvae that can consume up to 400 aphids in the two to three weeks before they pupate. They remain in cocoons attached to the bottom of a leaf for around a week before they hatch out as adults. If they hatch out near the end of the summer breeding season, they may never breed that year. However, most ladybugs live from one to two years, so they will have another chance. Many ladybug species overwinter in large groups on the south side of trees or houses.

This species manifests itself in two totally different forms: the more common ashy gray-blue seen here, as well as a jet black beetle with two distinctive red splotches, one on either side of its shell. This morph, as well as several similar species, are also called the “twice-stabbed lady beetle,” owing to the its “stabbed” coloration. However, one can distinguish Olla v-nigrum from the other species sharing its common name by looking for the distinctive white thoratic markings that set it apart from other “twice-stabbed” beetles.

Most coccinellids, although not this beetle in particular, are brightly colored to discourage predators. This adaptation, called aposematism, is useful because most brightly colored animals taste bad to predators, if they are not outright poisonous. The ladybug is no exception; being attacked automatically triggers a toxin which is exuded through its joints, making it undesirable to predators. Some species can even spray a venomous toxin when threatened.

Ashy gray lady beetles can be found across most of the US with their range ending in southernmost Canada, and south down to Argentina. This specimen was collected near the Brodie cabin.

Article by Hazel Galloway

Images of this organism can be viewed here, courtesy of Bugguide.net.

Sources:

  • everything-ladybug.com/ladybug-life-cycle.html
  • en.wikipedia.org/wiki/Coccinellidae
  • bugguide.net/node/ view/8874
  • Evans, Arthur and James Hogue. Field Guide to Beetles of California. 2006. University of California Press: Berkeley.